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IMPAIRMENT AND DISABILITY ASSOCIATED WITH EPIPHYSEAL DYSPLASIA IN CHILDREN
A thesis in conformity witb the requirements for the degree of Masten of Science
Graduate Department of Rehabilitation Science University of Toronto
@Copyright by Rita Damigiani, 2001
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IMPAIRMENT AND DISABILITY ASSOCIATED WITH EPIPKYSEAL DYSPLASIA IN CHILDREN
Rita Damignani Masters of Science
Graduate Department of Rehabilitation Science University of Toronto
200 1
ABSTRACT
The objectives of this study were to (i) develop an impairmeiit and disability profile
of children and adolescents with epiphyseal dysplasia and (ii) identify possible relationships
amongst the domains of impairment and disability.
A cross-sectifinal study of 28 subjects with epiphyseal dysplasia included evaluation
of i mpai ment and disabi lity measures. Impairment measures included anthropometric
indices, joint range of motion (ROM) and alignment, muscle strength and reports of pain.
Disability was measured using the Activities Scale for Kids (ASK).
Subjects presented with moderate to severe physical impairments yet with mild
physical disability. ED subjects were significantly overweight for their height and presented
with marked muscle weakness, findings not previously described in the literature. Few
relationships were identified between the domains of impairment and disability apart from
pain and physical disability.
Impairment findings indicate the need for a multi-disciplinary approach to the
comprehensive management of these patients. The relationship between impainnent and
disability is more complex than our present understanding.
ACKNOWLEDGEMENTS
1 was most fortunate to have the expertise of Dr. Elizabeth Badley, Dr. Nancy Young
and Dr. William Cole as members of my Program Advisory committee. Their involvement
and expert guidance will always be appreciated and remembered.
1 would also like to acknowledge Dr. Chantal Graveline and my colleagues in the
Department of Rehabilitation Services for their encouragement and support throughout my
studies.
1 am indebted to the patients with epiphyseal dysplasia and their farnilies who gave
their time to participate in this study. Acknowledgement is also given to Alison Anthony for
her expert role in perfonning the musculoskeletal assessments.
1 am forever grateful to my husband Shawn for his unyielding patience, support and
confidence in me throughout the course of my research.
TABLE OF CONTENTS
ABSTRACT ........................~.........................................................................e.......m.............................................. ii
... ACKNOWLEDCEMENTS .......................~....................................................................................................... 111
LIST OF TABLES .............. .. .............................................m...m....................e..........................~..........~.............. vi
..................................................................................................................... LIST OF FIGURES ............ .... vii
LIST OF APPENDICES ................... ,... .......e..m...................................................................................... viii
LIST OF ABBREWATIONS ............................................................................................................................. Lr
INTRODUCTION ........................................................................................................................m...................... 1
BACKGROUND .................................................................................................................................................. 2
EPIPHYSEAL DYSPLASIA (ED) ................... .. .......................................................................................... 2 hfultiple ëpiphysed Dysplnsicl (MEDI ....................................................................................................... 3 Sportdyloepipii), seal Dysplnsia (SED) ....................................................................................................... 6
THE EMERGENCE OF DISABLEMENT MODELS IN REHABILITATION RESEARCH .............. .... 7 fmpairmoat .................................................................................................................................................... 9 Disa bility/Activi@ Lirnitntions .................................. .. .............................................................................. IO Haridicap/Participnrion Resaicrion ............................................................................................................. 12
APPLICATION OF THESE MODELS iN REHABILITATION RESEARCH ............................................ 12 RELEVANCE OF DISABLEMENT RESEARCH iN REHABILITATION ................................................. 13
OBJECTIVES OF THE STUDY ... ............................. .................................................................................... 15
HYPOTHESIS ........................................................................................................................................... 16
.................................................................................................................................... S T W Y OVERVTEW 17 ETHICAL APPROVAL ................................................................................................................................. 18 SAMPLE SELECTION .................................................................................................................................. 19
........................................................................................................................................ Inclusion Criterin 19
..................................................................................................................................... Erclusion Criteria 19 Confirmation of the Diagnosis .................................................................................................................... 20
................................................................................................................................................ Stirdy Serthg 20 MEASURES OF PHYSICAL IMPAiRMENT .............................................................................................. 21
............................................................................. Anritroponte fric Indices: Nutritional Stattrs and Grorvrh 21 Joint Motion and Alignmerrr ........................................................................................................................ 22
........................................................................................................................................ hfuscle Strength 24 Pain ............................................................................................................................................................. 28
MEASURE OF DISABILITY ......................................................................................................................... 29 Activities Scale for Kids- ASK .............................................................................................................. 29
DATA ANALSMS..... ........................................................................................................................................ 32
........................................................................................................................ ....... RESULTS .................... 34
RESPONSE SUMMARY ................................................................................................................................ 34 .............................. ETROSPECTIVE DATA SUMMARY ; ......................................................................... 37
IMPAIRMENT MEASURES .......................................................................................................................... 39 A~itliroponretric Indices: Evaltration of Heigltt and Weight .................. .. ............................................. 39 Range of Motion .......................................................................................................................................... 44 Joint alignment and motion (JAM) Scores ................................................................................................ 48 Strength ........................................................................................................................................................ 50 Pain ............................................................................................................................................................. 55
................................................................................................................................................... DISABILITY 57 ASKp Scores .............................................................................................................................................. 57
RELATIONSHIPS BETWEEN THE DOMAINS OF IMPAIRMENT AND DISABILITY ......................... 62
DISCUSSION .................e............................................................................................................................. 6 4
PATIENT CHARACTERISTICS ................................................................................................................ 65 IMPAIRMENT PROFILE ............................................................................................................................... 67
Growth ........................................................................................................................................................ 67 Mctririon ...................................................................................................................................................... 71 Joint ROM and Alignnient ......................................................................................................................... 72 Strengrh .......... ., .................................................................................................................................. 73 Pain ................... .. ... .. ........................................................................................................................... 76
DISABILITY PROFILE ............................................................................................................................... 78 ........................................................................................................................................... ASKp Scores 78
ANALYSIS OF RELATIONSHIPS BETWEEN IMPAIRMENT AND DISABILITY ................................. 80 METMODOLOGICAL ISSUES AND LIMITATIONS ................................................................................. 82
Sample Selectiort/Resportse .. ................................................................................................................ 82 Impairment and Disability Tools ................................................................................................................. 84
CONCLUSION .................................................................................................................................................. 86
FUTURE mSEARCH ...................................................................................................................................... 87
REFERENCES .................................................................................................................................................. 89
LIST OF TABLES TABLE PAGE
Table 1. Distribution of respondents and non-respondents. 34
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Table 1 1.
Table 12.
Table 13.
Table 14.
Table 1 5.
Table 16.
Table 17.
Mean age and standard deviation (SD) for respondents and non- respondents. Gender distribution between respondent and non-respondents.
Gender distribution for MED and SED respondents.
Mean length of time since last visit to orthopaedic clinic for respondents and non-respondents.
Summary of patient characteristics derived fiom the medical record.
Summary statistics of Weight for age, Height for age and Weight for height 2-scores for ED (Total), MED and SED.
Sitting-height index (SHI) 2-score summary for ED (Total), MED and SED.
Sununary of median and interquartile ranges of motion (ROM) for ED (Total), MED and SED.
Summary statistics of Joint Alignment and Motion Scale (JAM) scores,
Summary statistics for overall, upper extremity and lower extremity mean strength z-scores.
Strength z-score surnmary for 10 upper and lower extremity muscle groups.
Right and left grip strength 2-score summary statistics.
Sumrnary of subjects' report of pain at rest and pain with activity
Sumrnary of VAS scores for pain at rest and pain with activity.
Summary statistics of ASKp, including individual domain scores.
Correlation matrix of impairment and disability outcomes.
vii
LIST OF FIGURE3S PAGE
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Height for age 2-score (HM) distributions for MED and SED 39 subjects (n = 1 1 and n = 17, respectively) compared to NCHS reference population according to Frisancho's (1 990) classification for the evaluation of growth status.
Weight for age Z-score (WAZ) distributions for MED and SED 40 subjects (n = 1 1 and n = 17, respectively) compared to NCHS reference population according to Fisancho's (1 990) classifications for the evaluation of growth status.
Weight for height 2-score (WHZ) distributions for MED and SED 40 subjects (n = 1 1 and n = 17, respectively) cornpared to NCHS reference population according to Frisancho's (1990) classifications for the evaluation of growth status.
Scatterplot demonstrating increasing J A M scores (indicating wone 50 outcomes) after t 2 years of age.
Boxplot figures showing the ASKc and ASKp scores for the ED 58 population.
Boxplots of ASKp scores for MED and SED subjects. 59
LIST OF APPENDICES
APPENDIX PAGE
Appendix 1. Ethics Approval 1 O0
Appendix 2. Information Letter to Parents Clinical Information Letter for Parents Consent Forms for 16 Years and Older Consent Foms for 4 6 Years Old Assent Foms
Appendix 3. Modified Joint Alignment and Motion (JAM) Scale 1 1 1
Appendix 4, Pain Assessrnent Form 112
LIST OF ABBREVIATIONS
ACH
ANOVA
ASK
ASKc
ASKp
CDC
CHAQ
CHCTD
COMP
cv ED
GHD
H M
HSC
ICIDH
JAM
JR4
LPD
MCP
MED
MMT
NCHS
Achondrodysplasia
Analysis of Variance
Activities Scale for Kids
Activities Scale for Kids (capability version)
Activities Scale for Kids (performance version)
Centre for Disease Control
Child Health Assessrnent Questionnaire
Centre for Heritable Connective Tissue Disorders
Cartilage Olignrnetric Matrix Protein
Co-efficient Variation
Epiphyseal Dysplasia
Growth Hormone De ficiency
Height for Age 2-score
Hospital for Sick Children
International Classification of Impairments, Disabilities and Handicaps
Joint AIignment and Motion
Juvenile Rhuematoid Arthritis
Legg-Perthes Disease
Metacarpal Phalangeal
Multiple Epiphyseal D ysplasia
Manual Muscle Tester
National Centre for Health Statistics
01
PSACH
ROM
SD
SED
SHI
VAS
WAZ
WHO
WH2
Osteogenesis hperfecta
Pseudoachondroplasia
Range of Motion
Standard Deviation
S pondyloepiphyseal Dysplasia
Sitting Height Index
Visual Analogue Scale
Weight for Age 2-score
World Health Organization
Weight for Height Z-score
INTRODUCTION
Epiphyseal dysplasias (ED) are a rare form of heritable connective tissue disorders
within the chondrodysplasia farnily. They are primarily autosomal dominant conditions
characterized by abnormal growth and development of the cartilage, ofien producing
complex musculoskeletal abnormalities and disproportionate short status. The majority of
the literature focuses primarily on the inheritance, aetiology, histologic and radiographie
features of this disorder. This information however, does not always address important
questions and concems raised by patients and farnilies regarding the impact of this chronic
disorder, particularly with respect to physical function. These questions raise important
issues that are central to rehabilitation research and practice.
This study sets out to identify the health experiences of children and adolescents with
epiphyseal dysplasia (ED) fiom a functional perspective. Disablement models exist to guide
our understanding of the consequences of chronic disorders at the level of the individual.
The overall goal of this research, therefore, is to develop a physical impairment and disability
profile of the ED population based on the International Classification of Impairments,
Disabilities and Handicaps (ICIDH) developed by the World Health Organization (WHO,
1980; WHO, 1993). This information will allow us to explore the relationship behveen
impairment and disability, potentially identimng additional factors influencing impairment
and disability. Integration of these results may assist in the determination of intervention and
the measurement of clinical outcornes for these patients.
BACKGROUND
EPlPHVSEAL DYSPLASIA (ED)
Classification and diagnosis of ED is based on the mode of inheritance as well as
clinical, histologic and/or radiographie features (Gershwin & Robbins, 1983; Silverman,
1996). Included within this classification are the multiple epiphyseal dysplasias (MED) and
the spondy loepiphyseal dysplasias (S ED). In both forms of the condition, the epiphyseal
ossification centres of several developing epiphyses are disturbed and disorganized. This
results in abnormal calcification processes, delayed appearance of ossification centres, a
decrease in epiphyseal growth as well as epiphyseal centre defonnities (Silverman, 1996;
Spranger, Langer & Weidmann, 1974; Wynne-Davies, Hall & Apley, 1985). In a study by
Schlesinger, Poznanski, Pudlowski & Millar (1986) establishing noms for standard height of
the distal femoral epiphysis, patients with bone dysplasias measured two or more standard
deviations below the mean for healthy children.
This irregularity of the epiphyses usually involves the joints symmetrically, oAen
Ieading to premature degenerative changes. Comrnonly pain is the primary finding,
particularly in the weight-bearing joints such as hips and knees and in the low back
(Andersen, Schantz, Bollerslev & Justensen, 1988; Cole, 1993; Ingram, 1992; Spranger et ai.,
1974; Wynne-Davies et al., 1985). In light o f these clinical characteristics, one would
assume that muscle strength is also affected. There appears to be little, if any published
articles descnbing muscle strength or potential pattems of strength imbalances among this
population. Strength impairments could potentially be related to early arthritic changes in the
joint, muscle atrophy around the involved joint due to pain and associated muscle inhibition,
and/or general inactivity.
M~iltipl e Epiplr vseal D vsplasia (MEDI
Multiple epiphyseal dysplasias (MED) are autosomal dominant conditions that are
pnmarily defined radiographically (Spranger et al., 1974; Wynne-Davies et al., 1 985).
Genetic research has descnbed MED as genetically heterogeneous with a wide range of
seventy (Deere, Blanton, Scott, Langer, Pauli & Hecht, 1995). Dietz and Matthews (1 996)
descnbe two distinct types of MED based on genetic and histologie studies: Type 1 which
involves a mutation of the gene responsible for cartilage oligometric matrix protein (COMP)
and type II which is caused by a mutation of the type IX gene. Mutations of the sulfate
transporting genes have also been reported (Dietz & Matthews, 1996; Deere et al., 1995;
Superti-Furga, 19991.
MED is the most comrnon of the epiphyseal dysplasias, although prevalence of MED
and SED are both relatively low. MED is reported to be 11 cases per index million (Wynne-
Davies et al., 1985) with diagnosis ofien made between the ages of 5 and 14 yean of age
(Bhowick & Kaste, 199 1).
Radiographie features include the late appearance of ossification centres with
irregularity of the epiphyses and later of the articular surfaces of the tubular bones. In middle
and late childhood the epiphyses are Bat as in the milder (Ribbing) form of MED, or small as
in the more severe and extensive (Fairbanks) form of the disease (Spranger et al., 1974;
Wynne-Davies et al., 1985). These dysplastic changes can lead to early and progressive,
degenerative processes, bilaterally, in large penpheral joints such as the hips and knees,
resulting in clinical findings of joint deformity and pain.
There may be some shortness of stature, primarily of the limbs (referred to as short-
limbed dwarfism) with relatively normal body proportions. Short-limbed dwarfism c m be
further subdivided into generai long bone shortening or shortening of the proximal, middle,
or distal segments of the extremities (Mahoney, 1987). Brachydactyly (generalized
shortening of the fingers) rnay be the result of cone-shaped epiphyses in one or more areas,
associated with premature fusion of the epiphyseal plates. This results in shortening of the
metacarpals or phalanges. Unlike the SED family, spinal involvement in MED is confined to
mild platyspondyly (vertebral flattening) and vertebral end-plate irregularity in the lower
thoracic spine (Andersen et al., 1988; Spranger et al., 1974; Treble, Jensen, Bankier, Rogers
& Cole, 1990; Wynne-Davies et al., 1985).
MED is sometimes misdiagnosed as bilateral Legg-Perthes disease (LPD) (Andersen
et al., 1988; Ingram, 1992; Treble et al., 1990). Legg-Perthes disease, however, affects only
the capital femoral epiphyses, and ofien exhibits patches of increased density in the
epiphyses with marked metaphyseal involvement with cyst-like changes (Ingram, 1992).
Perthes is also cbaracterized by an active phase of worseniag, followed by improvement.
This is unlike the course of bone dysplasias in which patients tend to have more difficulty
with increasing age (Andersen et al., 1988; Wynne-Davies et al., 1985).
Pseudoachondroplasia (PSACH), an autosomal dominant condition, is a form of
epiphyseal dysplasia that is characterized by short stature and early onset osteoarthritis much
like MED. The short stature and disproportionately short limbs are often not apparent until
2-3 years of age. The epiphyses of the long bones are grossly abnomal and as a result the
epiphyses are ofien delayed in time of appearance, small, irregular and fragmented. These
changes are most obvious in the hands and feet as well as more proximally. Joint deforinities
may occur secondary to osteoarthritis. Some patients may have a gross degree ofjoint laxity
with either genu valgum or varum (Tachdjian, 1997).
Similarities of morphologie and biochemical abnormalities strongly suggest that
MED and PSACH belong to the same dysplasia family (Stanescu, Stanescu, Muriel &
Maroteaux, 1993). The gene for PSACH has been mapped to a region of chromosome 19,
similar to MED (Deere, 1995; Online Mendelian Inhentance in Man [OMIM], 2000) .
Severe cases of MED and mild cases of PSACH, may resemble each other closely,
particularly with respect to the presence of small femoral epiphyses. Usually, there is more
severe involvement of the vertebral bodies in children with PSACH. Marked hyperlaxity of
the joints also favors a diagnosis of PSACH (Spranger et al., 1974). Differential diagnosis
fiom the severe form of MED is made mostly from a pelvic radiograph. In PSACH,
development of the pelvis is disorganized and delayed, with poor formation of the
acetabulum and widening of the tri-radiate cartilage (Wynne-Davies et al., 1985).
Spondyloepiphyseal dysplasias are a form of chondrodysplasia which involve
phenotypical abnomalities associated with the COL 2A1 gene which code for Type II
collagen (Cole, 1993; Dietz & Matthews, 1996). The incidence is reported to be 3 to 4 cases
per index million with marked heterogeneity existing (Wynne-Davies et al., 1985).
There is progressive involvement of the epiphyses of the long bones, particularly
those of the proximal and distal femur and proximal tibia. Dysplastic epiphyses result in
joint defonnities, restncted joint mobility and early onset osteoarthritis, particularly of the
hip and knee. Radiographically, al1 SED patients present with platyspondyly (congenital
flattening of the vertebral bodies) with varying degrees of short stature involving the spine.
(Tachdjian, 1 997; Wynne-Davies et al., 1 985).
SED is often identifiable at birth or early in childhood due to short stature ancilor to
the development of a waddling gait. SED patients cm present with coxa vara of varying
degrees with high-nding femoral trochanters and normally located, small, deformed femoral
heads (Spranger, 1974). There may be associated anomalies such as myopia with subsequent
retinal detachment, sensorineural hearing loss, and cleft palate. Odontoid hypoplasia and
delayed ossification of the odontoid process is common and may lead to atlantosccipital
dislocation with cervical cord and root compression. In addition to platyspondyly, spinal
involvement can include the development of scoliosis during childhood or adolescence or an
exaggerated donal kyphosis. Marked lurnbar lordosis, often with genu valgum or varus,
leads to a waddling gait (OMM, 2000; Tachdjian, 1997; Wynne-Davies et al., 1985).
In skeletal dysplasia, stature can often reflect the severity of the disease. SED
patients with very short stature usually have severe coxa vara and frequently have associated
anomalies; those with mild short stature usually have mild coxa vara and lower fiequency of
associated anomalies (Haga, Nakamura, Takikawa, Manabe, Idegawa & Kimizuka, 1998).
An associated member of the SED family includes the Kneist-type SED. In this
autosomal dominant condition there is marked delay in ossification at the hips, platyspondyly
with marked short-trunk dwarfism, progressive kyphoscoliosis, and progressive joint
limitations. The joint deformity and limitation are most marked at the knee and small joints
of the hands, making it difficult to make a tight fist. Kneist-type SED patients also present
with associated anomalies such as myopia with progressive retinal detachment, hearing loss
and clefl palate (Dietz & Matthews, 1996; OMM, 2000).
THE EMERGEME OF DISABLEMENT MODELS INREUABILITATION RESEARCH
The majority of existing research on chronic disorders, including the
chondrodysplasias, is predominantly based on the medical mode1 of disease:
A limitation of this model, however, is the lack of sensitivity in reflecting the effect
of disease at the level of the individual (Martini, Polatajko & Wilcox, 1995). The emergence
of chronic disease as a significant health and social problem has identified the need for a
conceptual model that goes beyond the limitations of the medical model (Granger, 1984;
Badley, 1993; Jette, 1994). A variety of disablement models exist to better describe the
impact a d o r consequences of chronic disease or illness in terms of Funciional outcomes.
The major goal of these models is to delineate the major pathways fiom disease activity or
pathology to various types of fiinctional consequences (Badley, 1993; Duckworth, 1984;
Jette, 1994; Verbrugge & Jette, 1994; Wagstaff, 1982). The terni "disablement" was
originally developed by Phillip Wood in 1980 to collectively describe the health expenences
of individuals as the consequence of disease, injury or congenital anomolies. In the past 25
years, two important schemes have guided disability research in rehabilitation. The first was
a model developed by sociologist, Saad Nagi (1965). The four central concepts of Nagi's
model include:
The second model, the International Classification of Impairments, Disabilities and
Handicaps (ICIDH) was developed in 1980 by the World Health Organization based on the
work of Philip Wood and Elizabeth Badley (Wood, 1980; Wood & Badley, 1981). The tem
"disablement" was used as a collective descnptor of the health experiences related to:
This classification was developed to offer a theoretical framework with which to interrelate
impairment, disability and handicap (Badley, 1993). In a continuing effort to provide a more
sensitive appraisal and better understanding of the consequences of diseases and disorders at
the level of the individual, the mode1 continues to be revised. This has resulted in the
development of the World Health Organization's ICIDH-2 (WHO, 1999) which is presently
in the stages of testing and revisions. The terminology of the ICIDH-2 has been changed to
include the terrns:
BODY FUNCTIONS >ACTIVITY LIMITATION>PARTICIPATION RESTRICTION
Today, the term "disablement" refers to the vanous impacts of chronic conditions on
the functioning of (i) speci fic body systems, (ii) basic human performance and (iii) expected
societal roles. The central focus of the Nagi and ICDH schemes was to delineate a pathway
for the consequences of disease or pathology and serve as the 'bbasic architecture" for
disablement research (Jette, 1994). For purposes of clarity, a detailed description of the
components inherent to each of these conceptual models will be discussed.
Both Nagi and Wood agreed upon the deution of "impaixment"(DuckWorth, 1984;
Granger, 1984; Jette, 1994) which has been defined as "any loss or abnormality of
psychological, physiological or anatomical structure or function" (WHO, 1980; WHO, 1993).
Impairment is further defined by the ICiDH as "exteriorizing" a pathologic state, reflecting
disturbances at the "level of the organ" (WHO, 1980).
The more recent work of the ICIDH-2 describes impainents with respect to body
functions- the physiological or psychological fùnctions of body systems and body structures,
as well as anatomical parts of the body such as organs, limbs and their components. Here,
impaiments are descnbed as problems in body function or structure. For medical users of
this classification system, the ICIDH-2 reinforces that impairments are not the same as the
underlying pathology, but are the manifestations of that pathology (WHO, 1999).
Disabiliîv/Activitw Limitations
Differences in disablement models begin to emerge when defining "disability". Nagi
used the term "functional limitations'*, linking "impairments" as the cause of "functional
limitations" and "functional limitations" as the cause of "disability". Here, the term
"disability" represents the final state of the pathway, equivalent to "handicap" in the ICIDH
model. The term "disability*' was used to mean inability or limitations in performing social
roles or activities (Granger, 1984; Nagi, 1965).
Within the ICIDH framework, disability is defined as "any restriction or lack of
ability to perform an activity (due to impairment) in the manner or within the range
considered normal for a human being" (WHO, 1980; WHO, 1993). This is similar to the
term "functional limitation" used by Nagi (1965). Measures of disability, as descnbed by the
WHO, look beyond "impairment" rneasures and are recognized for their relevance to daily
life activities. "Disability" is concemed with abilities that are generally accepted as essential
components of everyday life (WHO, 1993).
A commonly used term in the literature on outcome measures and the consequences
of disease is "functional limitation". Although the terni "functional limitation" is not defined
iii the ICIDH, Badley (1 993) describes the term as a bridge between impairment and
disability. An example is given where impairment in the strength and range of motion of the
a m could lead to functional limitations in grasping or reaching. These in tum give nse to
disabilities, such as reaching for high objects or dressing.
More recently, the ICDH-2 has substituied the term "activity limitation" for the term
disability. "Activity is limited when the individual, in the context of a health condition,
either has difficulty performing the activity in an expected manner, or cannot perfonn it ai
all" (WHO, 1999).
Consistent with the terminology descnbed in the ICIDH mode1 (WHO, 1980),
disability scales exist based on physical activity performance. These scales provide useful
information that can be used to identiQ and assess the impact of disease or illness on
physical function. They may also be used to more appropnately assess health care
interventions (Young, 1994; Young & Wright, 1995b).
HandicaII&Particwa!ion Restriction
The final dimension of disablement models is referred to as "handicap" within the
ICIDH framework. Here "handicap" is defined as a "disadvantage for a given individual,
resulting from an impairment or a disability, that limits or prevents the filfilment of a role
that is normal [depending on age, sex, and social and cultural factors] for that individual"
(WHO, 1980; WHO, 1993).
The ICiDH-2 refers to this third dimension as "participation restriction" as opposed to
"handicap" (WHO, 1999). These are defined as 'bproblems an individual may have in the
manner or extent of involvement in life situations". The term "handicap" and "participation
restriction", therefore, can be seen as interchangeable in their application.
APPLICA TION OF THESE M W S IN REHABILITA TION RESEARCH
A review of the literature has identified application of these conceptual fiameworks to
specific disease processes. Badley, Wagstaff & Wood (1984) first explored the use of the
ICIDH mode1 in a study of arthritis-related disability in relation to impairment of range of
joint movement. The authon were able to demonstrate that groupings of disabilities were
reflected in problems with particular joints or groups ofjoints. Bostrom, Hanns-Ringdhal &
Nordemar (1995) investigated the relationship between measurements of impaiment,
disability, pain and disease activity in rheumatoid arthritis patients with shoulder problems
utlilizing the fiamework of the ICIDH. Fowler et al. (1995) recently applied this similar
framework to a paediatnc population in an attempt to develop comprehensive impainnent
and disability profiles of the clinical characteristics of a group of seven neuromuscular
diseases. Recently, there has been considerable interest in the area of paediatric impairment
and disability as demonstrated in the Scandinavian literature. Van der Net et al. (1996; 1997)
studied the impact of polyarticular juvenile chronic arthritis and systemic onset juvenile
chronic arthritis on functional outcorne. Recently, Engelbert, van der Graf, van Empelen,
Beemer & Helders' (1997) work fiom the Wilhelmina Children's Hospital in Utrecht, The
Netherlands speaks directly to the impairment and disability associated with osteogenesis
imperfecta. The consistent locus of the above-mentioned research is to assess the
relationship between impainnent and disability charactenstics, recognizing that disability is
"one of modem society's geaiest public health problems, affecting individuals, families, and
society" (van der Net, 1997, p. 188).
RELE VANCE OF DISABLEMENT RESEARCH IN REHABILITA TION
Understanding the complex process of disablement is essential in rehabilitation
research. A functional perspective of chronic disease and illness equips health practitioners
with a conceptual framework for planning treatrnent when the emphasis is no longer on cure,
but on living with an ongoing disorder (Badley, 1993). Development of a functional
perspective in analyzing consequences of a health problem requires understanding of the
concepts and relationships between impairment and disability. tn his chapter entitled, "A
Conceptual Mode1 for Functional Assessment", Car1 Granger (1984) suggests that although
interrelationships exist behueen impairment, disability and handicap, impairment by itself
should not be considered "a necessary and sufficient cause for disability" (p. 19).
Granger (1984) and Badley (1993) describe the practical application of this approach
for medical and rehabilitation professionals. Interventions can be based on the systematic
development of problem lists that include limitations in function. Additionally, treatment
effectiveness and efficiency can be established by assessing impairment and disability after
treatment interventions, thus detennining the benefits of clinical care. In addition,
appropriate treatment resources can be identified and developed based on the needs of a
defined population when samples of individuals representative of that population have been
studied. Such an approach to the study of chronic conditions can potentially assist with
program evaluations aimed at ultimately improving resources to the population under study
(Granger, 1984).
OBJECTIVES OF THE STUDY
Based on out present understanding of disablement, this study sets out to determine
an irnpairment and disability profile of a population of children and adolescents with
epiphyseal dysplasia. This information will contribute to an existing gap in knowledge in
this specific population of patients. The conceptual h e w o r k and the terminology of the
ICIDH (impairment and disability) (WHO, 1980) will be used because of its wide acceptance
and Familiarity within disability research. The terms of the ICIDH-2 (body functions and
activity limitations) (WHO, 1999) could, however, be easily substituted.
Physical impairments are evaluated by measures of growth and nutritional status,
joint motion and alignment, strength and pain. Physical disability is evaluated using an
activity scale- the Activities Scale for Kids (ASK) (Young, 1994). Multiple epiphyseal
dysplasia (MED) and SED are both described individually with respect to clinical
characteristics of impairment and disability and are compared with respect to disease
severity. The relationships among impairment findings are descnbed. In an effort to explore
the impact of this disease on functional outcome, the relationship between impairment and
physical disability outcomes are also described. The specific objectives of the study are
summarized:
1. To measure and describe patterns of impairment and disability associated with ED in
children and adolescents, including descriptions of each of the 2 subgroups - MED and
SED.
2. To compare the extent and severiéy of impairnent and disability patterns amongst the
MED and SED subgroups.
3. To identify possible relationships among impairment items and between impairnent and
disability items.
H YPO THESIS
Although this is largely a descriptive study on a population of subjects with ED, the
existing disease and disablement literature does allow for some hypothesis testing. The
following hypotheses will be tested:
1. SED subjects will present with greater impairment than MED subjects.
2. SED subjects will present with greater disability than MED subjects.
3. There is a relationship between impairment findings and disability outcomes.
METHODS
STUDY OVERVIEW
This study was a cross-sectional analysis of consenting children and adolescents with
a diagnosis of epiphyseal dysplasia confinned at the Hospital for Sick Children (HSC), an
acute tertiary care hospital within a large urban centre in Ontario, over a period of one year.
Eligible children were identified for the study and information was made available from the
HSC's Centre for Heritable Connective Tissue Disorders (CHCTD) database. The database is
onc of the largest of its kind in Canada, with patients referred from al1 areas of Ontario.
Consistent with the HSC's Research Ethics Board protocol, eligible children and their
families were mailed an information letter from the CHCTD descnbing the research study.
Families interested in participating in the study were provided with a contact number andlor
postage-paid response card to indicate their interest to the primary investigator. These
responses were then followed-up by the primary investigator. Newly diagnosed patients
were also identified at the HSC's orthopaedic c h i c by nursing staff and physicians.
Families were given the appropriate research information at the time of diagnosis and the
narnes of families that were interested in the siudy were then forwarded to the primary
investigator for follow-up. It was made clear to the farnilies and children that participation
was voluntary and that their decision would in no way effect the quality of care that they
would receive at the HSC.
The HSC medical record was reviewed by the p n m v investigator following consent
from al1 eligible subjects and their families. Relevant data were collected using a
standardized protocol. Data collection included: demographic data, diagnosis, description of
orthopaedic surgical procedures and dates, description of skeletal deforrnities and related
management, presence of myopia or visual disturbances, neurosensory hearing loss as well as
cleWlip or palate .
A physical assessment was completed by a single, licensed physical therapist with
several yean of experience in paediatric orthoapedic assessments. At the time of assessment,
patients were asked to complete responses to questions regarding pain and were asked to fill
out a pain scale if pain was reported. Subjects wcre also asked to fill out a 2-part
questionnaire assessing thcir overall physical ability (Activities Scale for Kids-ASK).
E THICAL APPRO VAL
Prior to the start of data collection, ethical approval for this study was obtained from
the HSC's Research Ethics Board (Appendix 1). Inforrned assent was obtained from al1
participating children and infomed written consent was obtained fiom their parents or
guardians prior to participation in the study (Appendix 2). A Trainee's Start-up Grant fiom
the Hospital for Sick Children and a gant fkom the Bloorview Children's Foundation
provided Funding for this thesis.
SAMPLE SELECTIOlV
Inclrrsion Criteria
Al1 patients 5 to 20 yean of age with a diagnosis of MED (including PSACH) oï SED
(including SEDC and Kneist Syndrome) confinned at the Hospital for Sick Children (HSC)
were considered eligible for the study. The minimum age of 5 years was chosen to irnprove
the accuracy of performing clinical measures such as muscle strength testing. Eighteen is the
maximum age of patients seen at this paediatric centre, however patients 19-20 years of age
who continued to have contact with the centre were included in the study to maximize the
number of subjects. Patients were identified as eligible for the study during the period
between July 1999 and August 2000.
Children who had undergone surgical procedures were included in the protocol;
relevant information regarding the type and date of surgery was collected ftom the medical
record because of the possible influence on pnmary outcomes (impairments and disabilities).
Children younger than 5 years of age, with a diagnosis of MED or SED were not
considered eligible for the study (as previously explained). Eligible children with identified
cognitive impairments were excluded fiom the study because of the anticipated difficulty in
complying with the assessrnent form and study protocol. Additionally, families who did not
have sufficient command of the English lenguage to complete the questionnaire were also
excluded fiom the study.
Cori firnntion of the Dinpriosis
Classification of subjects (MED or SED) was determined by the degree of spinal
involvement. An experienced orthopaedic surgeon (WC) with expertise in the field of
skeletal dysplasias reviewed existing spinal x-rays to ensure appropriate classification of
patients. The presence of vertebral end-plate irregularity, particularly at the thoracolumbar
junction, was accepted as a feature of MED, however the presence of platyspondyly was
regarded as signi fying SED and was therefore classified as such.
Eligible children and their families were initially contacted by mail and then followed
up by the pnmary investigator by phone once a response was received indicating interest in
the study. Data was collected over the period of one year (July 1999- August 2000).
Assessments were ofien perforined at the time of a patient's scheduled follow-up visit to
orthopaedic clhic at the HSC. Patients not scheduled for follow-up in orthopaedics during
the year timeframe of the study were asked to attend an appointment at the HSC's
Rehabilitation Services Department (Division of Physiotherapy) at a mutually convenient
time in order to complete the study protocol.
A n tli r o ~ o m etric In dices: Nid tritiort al Statu s and Gro wtli
The nutritional status of children with epiphyseal dysplasia has not been well
described in the literature. For this study, weight measures in kilograms were taken for al1
subjects and were reported to the nearest 100 gram using a consistent, platforni-beam scale
with moveable weights. The subjects were asked to stand still over the centre of the
platforni with body weight evenly distributed between both feet.
Relevant indices for growth in this population are the measurernent of standing height
and sitting-height. Both were measured at the time of the physical assessrnent according to
Gibson's description (1990). Standing height was assessed using a standiometer which
consisted of a metric tape affixed to a vertical surface, with a moveable headpiece attached
that could be brought down to the crown of the head. Patients were asked to stand with their
heels, buttocks and shoulders and head touching the wall, with the examiner applying a
gentle pressure under the mastoid process. The moveable headpiece was brought down until
it touched the head.
A useful indice of body proportions are the upper to lower segment (UtL) ratio. The
mean body UR. ratio is about 1.7 at birth, 1.3 at 3 years, and 1 .O after 7 years of age (Hall,
1992; Mahoney, 1987). Sitting height was taken with the child sitting on a table with hisher
feet hanging down unsupported over the edge and hisher head, shoulden, and buttocks
touching the vertical surface of the meauring âevice. The child's back was then stretched up
straight with a gentle pressure under the mandible. The moveable headpiece was then moved
down to the child's head, at which time the patient was asked to sit tall. Sitting height was
measured to the last .1 centimetre. The upper to lower segment ratio is often referred to as
the sitting height index (%). This was derived by computation as the ratio of sitting height to
stature times 100 (Gibson, 1990):
Sitting Height Index (%) = [sitting height (cm)/stature (cm)] x 100
Joint Motion and Alihment
In-egularity and defonnity of the joints are part of the dysplastic changes that result in
restricted joint mobility, joint defonnities and early degenerative arthritic changes arnong
patients with epiphyseal dysplasia. In order to assess joint mobility and alignment, 18 ROM
measures in 9 joints bilaterally were obtained with a standard two-legged goniometer.
Previous studies on reliability of goniometric measurements have been shown to Vary
considerably (Barr, et al., 1991; Boone et al., 1978; Rothstein, Millar & Roettger, 1983;
Watkins, Riddle, Lamb & Personius, 199 1). Pandya et al. (1 985) completed a study to
determine the intratester and intertester reliability of goniometric measurement of seven
common upper and lower extremity joint limitations in children with Duchenne muscular
dystrophy. The results of this study suggest greater intrarater reliability (ICC = .81 to -94)
than interrater reliability (ICC = .25 to .91). Most studies indicate the need to use the same
examiner when evaluating joint ROM using a standardized goniometer, as was done in this
study.
Based on these standardized goniometric measures, a modified Joint A l i m e n t and
Motion (SAM) scale developed by Parker, Harrell & Alarcon (1988) was used to evaluate
bilateral upper and lower extremity ROM and alignment ). The JAM is a 5-point scale that
assesses the percentages of arc of motion lost and the amount of joint instability or
rnalalignment present (Parker et al., 1988; Spiegel, Spicgel& Paulus, 1987). The JAM scale
was initially developed by Spiegel et al. (1987) to examine the impact ofjoint defomity on
functional status in rheurnatoid arthritis patients. When tested among adult patients with
rheumatoid arthritis, the JAM score demonstrated good interobserver reliability (F 0.72),
was stable over time and was strongly cczelated with self-reported functional measurement,
walk time and grip strength (Spiegel et al., 1987).
According to the JAM scale, a joint with a normal ROM or alignment is assigned a
score of O. If the examiner feels that either ROM or alignment is possibly decreased, a score
of 1 is given. When ROM is mildly decreased (6.25% of normal) or where there is mild
rnalalignment, the JAM score is 2. JAM scores of 3 (26% -75% decreased ROM or joint
subluxation) and 4 (76- L 00% decreased ROM, joint fusion or dislocation) represent more
severe and oAen quite obvious defomity. The JAM score for an individual joint is the most
severe or limiting aspect of either alignment or motion.
After each joint is assigned an individual score, a global JAM summary score with a
possible range of 0-72 can be established. Global upper extremity J A M scores (0-40) and
lower extremity SAM scores (0-32) can also be established.
Muscle StcenPtIa
In an effort to establish a more accurate and clinically meaninghil quantitative
measure of strength, isometric force measurements were taken with a portable electronic
dynamometer- the Nicholas Manual Muscle Tester (MMT) manufactured by Lafayette
Instruments. The Nicholas MMT is a hand held device, which quantifies the breaking force
necessary to depress a limb held in a specific position by the subject. This method is
described as a more objective and quantitative categorization of muscle strength than the
MMT described by Daniels and Worthingham (1986) which is subject to individual tester
bias of interpretation with regard to age and sex of the patient (Schwartz, Cohen, Herbison &
Shah, 1992)
Several studies have tested the intrarater reliability of the portable dynarnometer
(Agre et al., 1987; Backman, Odenrick, Henri ksson & Ledin, 1989; Bohannan, 1986).
Bohannon's (1 986) retrospective study compared three consecutive dynamometer strength
scores recorded for 18 muscle groups in a sample of 30 neurologically involved patients.
Retests of specific muscle groups were perfomed 10 to 30 seconds apart after the initial test.
When using the Pearson product moment correlation to calculate correlation for pairs of
strength scores (Le. first and second, second and third, and first and third scores), al1
correlations were significant @<.01). Median and modal correlations were all.97 or .98. A
one-way analysis of variance (ANOVA) for repeated measures was perfomed within the
study to identify systematic differences in scores; significant differences in repeated
dynarnometer test scores were only revealed for hip and shoulder abduction. The results of
this study suggest that hand-held dynamometry can be a reliable assessrnent technique when
used by a single, experienced therapist.
Agre et al. (1987) also found that intrarater reliability was reasonably good (r = 0.88
to 0.97) when upper extremity testing was performed using a hand-held dynamometer. The
coefficient variation (CV), which provides an indication of the percentage of variation from
trial to trial, varied from 5.1% to 8.3%. Intrarater correlation CO-efficients for lower
extremity testing were much lower than for upper extremity testing, ranging from 0.44 to
0.96 with CV's ranging fiom 11.3% for knee flexion to 15.9% for ankle dorsiflexion.
Backrnan et al. (1 989) also studied the portable electronic dynamometer method for
measuring muscle force in children, identifying that this method was simple to use and
dcmonstrated reproducible results under standardized conditions. The Swedish study tested
muscle force for 10 different muscle groups in 219 healthy children between the ages of 3.5 -
1 5 years. To assess the reproducibility of the method within a single investigator, a class of
24 children aged 13- 13.5 years was tested twice within an interval of 3 months. The
estimated coefficient of variation of measurement error varied in the ten rnu:;cle groups from
6% of the muscle force (elbow flexors) to 16% (hip flexors). When ten 6-year-old children
were tested iwice by the same investigator within an interval of 3-14 days, the coefficient of
variation of measurement error was estimated to be 6% for the ankie dorsiflexors and 12%
for the elbow flexors. The study concluded that the standard error of a single determination
made by the same observer was roughly 9% of the force, suggesting that this was an
acceptable method to be used in clinical practice. Subsequently, reference values for gender
and age (3.5 io 15 years of age) were established for muscle force in heaiîhy children for 10
di fferent muscle groups.
In summary, a review of the literature revealed few available strength reference
values for children related to gender and age. Although not ideal, this study was limited to
the results published by Backman et al. (1989). As a result, al1 strength measurements, the
muscle groups examined, the procedure, and the test positions were chosen to match the
existing reference values as described by Backman et al. (1989). Isometnc muscle force was
measured for shoulder abductors, elbow flexors and extensors, wrist extensors, hip flexors,
abductors, and extensors, knee extensors and flexors, and ankle dorsi flexors. The instrument
consisted of a hand-held force transducer, an electronic display and an amplifier unit. The
peak force is expressed in kg with an operating range of 0-35 kg with accuracy up to +/- 0.5
percent of full scale (Lafayette Instrument Instruction Manual).
A standardized protocol that indicates sites of fixation and application of resistance,
as well as the posture of the child in the test position, was used (Backman et al., 1989). The
1 O muscle groups on each side were measured 3 times within an interval of 1- 3 minutes.
The breaking force technique was used with an isometric contraction of at least 2-3 seconds.
The peak force value of the three repetitions was the documented strength measure for each
of the 10 movements. The process took approximately 30-35 minutes to complete for each
subject dependent on age and cornpliance.
Bilateral g i p strength was assessed in dl patients using the JAMAR grip
dynamometer, developed by Asimow Engineering. Mathiowetz, Weber, Volland &
Kashman (1 984) studied the validity and reliability of the JAMAR dynamometer arnongst 27
college women ranging from 20-39 years of age. Standard positioning and instructions (as
recommended by the American Society of Hand Therapists) were used to establish grip
strength measures. Standard positioning and instructions were used. This standardized
procedure demonstrated high intrarater reliability when correlations of two separate
observations of hand strength tests were assessed a week or less apart (r = .85). Inter-rater
reliability was high with a correlation CO-efficient of .97 or above for al1 tests. Calibration
accuracy of the JAMAR dynamometer was 2 3% suggesting that this tool is a valid measure
of grip strength (Mathiowetz et al., 1984).
Gnp strength measures of al1 ED subjects were perfonned. For each test of hand
strength, the subjects were seated with their shoulder adducted and neutrally rotated, elbow
flexed ai 90 degrees, forearm in neutral position, and wrist between O degrees and 30 degrees
dorsiflexion and between O degrees and 1 5 degrees of ulnar deviation. The standard,
adjustable-handle was set ai the second position for al1 subjects. It was held lightly around
the readout dia1 by the examiner to prevent inadvertent dropping and specific verbal
instructions were given to subjects. The same instruction was given for three successive
trials; the mean of the three trials was used as the measure of grip strength. The protocol
used was identical to that described by Mathiowetz, Wiemer & Feldertnan (1 986) when
developing grip strength noms for children 6-19 years of age.
Results were then compared with the scores of healthy individuals of the same age
and sex as established by Mathiowetz et al. (1986). In Mathiowetz et ale's study, eight
trained testers used standardized positioning and inshuctions to test a sample of 23 1 males
and 240 females ranging Rom 6 to 19 years of age. This resulted in the establishment of grip
strength noms for children 6- 19 years of age.
Pain has been described in epiphyseal dysplasia in general ternis as a primas, finding
in childhood or early adolescence, particularly in the weight-bearing joints such as hips and
knees and in the low back (Ingrarn, 1992; Wynne-Davies et al., 1985; Spranger et al., 1974).
In Our study, two separate Visual Analogue Scales (VAS) were used to measure both pain ai
rest (within the last 24 hours) and pain with activity. The latter referred to the overall
experience of pain with activity. Subjects were instructed to mark the line to indicate the
overall severity of their pain. The scrle was anchored at O cm ("no pain") and 10 cm (worst
pain possible), producing a 10-point scale. The distance of the mark from the end of the
scale was then taken to represent the severity of the pain, to the nearest millimetre.
The VAS has been described as a simple technique of measuring subjective
experience of pain that allows for the use of nurnencal values suitable for statistical analysis
(McComack, Home & Sheather, 1988). Children as young as 5 and 6 years of age have
been reported as successfully completing the scale for assessing arthntic pain intensity
(Huskisson, 1983; Varni, Thompson & Hanson, 1987). The measurement properties of the
VAS have been investigated with both children and adults ( G a 1989; McComack et ai.,
1988; Price, McGrath, Rafi & Buckingham, 1973). The VAS, "although deceptively simple,
has demonstrated the reliability, validity, minimum inherent bias, and versatility necessary
for an objective pain measure in a variety of experimental and clinical pain studies" (Vami et
al., 1987, p. 148). In both children and adults, the VAS has demonstrated excellent construct
validity in chronic musculoskeletal pain, demonstrating the expected increase in perceived
pain intensity with greater rheumatic disease activity (Vami et al., 1987).
In addition to the VAS, children were asked to verbally describe their pain, including
the location and duration of pain. This information was documented on the standardized pain
assessrnent form (Appendix 4).
MEASCrRE OF DISABILITY
Acriviries Scale for Kids- ASK
The Activities Scale for Kids (ASK) developed by Young (1994) was chosen to
measure physical disability in the subjects participating in the study. The ASK is a unique,
thirty-item, self-report measw of physical disability in children with neuromuscular and
musculoskeletal conditions between the ages of 5 and 15 years. It has been used in a
previous study to evaluate physical disability in individuals up to 20 years of age (Graveline,
Young & Hwang, 1998). The ASK provides a standardized as well as reliable, valid and
responsive measure of disability in children (Young, 1994; Young, Williams, Yoshida &
Wright, 2000). The tool is a unique disability scale that identifies the important role of
children as cornpetent respondents in physical disability measurement. The ASK has high
test-retest reliability (intraclass correlation coefficient [ICC]= 0.97) (Young, Yoshida,
Williams, Bombardier & Wright, 1995a). Content validity was established by a significant
correlation of the Child Health Assessrnent Questionnaire and the clinician reported ASK
scores (Pearson's correlation CO-efficient +0.83 and 0.90 respectively) (Young, 1997; Young
et al., 2000).
The ASK has both a capability version (ASKc) and a performance version (ASKp)
which allows for the cornparison of what the children are capable of and what they actually
do in their regular activities (Young, Williams, Yoshida, Bombardier & Wright, 1996). The
performance version of the tool yields lower scores with wider distribution than the
capability version (Young, 1994).
The ASK allows for identification of specific domains of ability in al1 children.
These include personal care, dressing, eating and dnnking, misceIlaneous, play, locomotion,
standing skills, stairs, and transfers. Each physical activity has a potential score of O- 4.
Scores are expressed in percentages. A perfect score (100%) indicates complete
independence in a particular task without any difficulty. Global scores are calculated as
averages of the individual items.
Al1 subjects were asked to complete both the ASK capability (ASKc) and ASK
performance (ASKp) questionnaire ai the time of their physical assessrnent according to
standardized administration guidelines (Young, 1997). Although children are the preferred
reporters when using the scale, the assistance of parents was necessary for some of the
younger children in the study. Previous work by Young et al. (1995a) identified the
concordance of parent and children scores (ICC= 0.96) for physical disability, thus
supporting the role of parents as surrogate respondents. In some cases, the questionnaires
were completed at home (due to reasons of time constraints) and were mailed back to the
primary investigator.
DATA ANALSYIS
The data were entered onto an Excel spreadsheet and then imported into Minitab
Release 12 statistical software programme. Data used in the analysis was double-entered to
identiS, potential data entry errors. Data was checked against raw data sheets and corrected
where necessary. Missing values were coded as such.
Descriptive statistics were calculated to characterize the population. Because the
number of children who chose not to participate w3s high, the respondents and non-
respondents were compared for gender, age and diagnosis. A t-test was used to establish if
the groups differed in age. A 2 X 2 chi-square analysis was used to identify differences of
gender and diagnosis (MED vs. SED) within respondent groups and between respondent and
non-respondent groups.
Height and weight values were transfonned into 2-scores using EpiInfo 2000, a
package of public domain cornputer programs for handling epidemiologic data. 2-scores
have been described as the preferred method for evaluating anthropometric data because of
their ability to accurately classi@ individuals with indices below the extreme percentiles of
the reference data (Gibson, 1990). The Nutstat module in EpiInfo, a nutritional
anthropometry program for recording and evaluating measurements of stature and weight,
calculates numben of standard deviations fiom the mean (2-scores) using 1 977/1985 U.S.
growth charts from the Centre for Disease Control and Prevention (CDC) and the World
Health Organization (WHO). These revised growth charts have been recognized for their
improved statistical smoothing procedures and their expanded data, thus producing an
enhanced instrument to evaluate the growth of infants and children (NCHS, 2000).
Strength values (including grip strength) were also transformed into 2-scores using
strength references based on age and gender (Bachan et al., 1989; Mathiowetz et al., 1986).
A one-sarnple t-test was performed to test for significant differences From the reference
populations. Z-score differences in strength between the MED and SED subgroups were
analyzed using a 2-sample t-test.
Range of motion values are more cornmonly descnbed as median values and
interquartile ranges therefore a median test (Mann-Whitney test) was used to compare
differences in median ROM values between MED and SED subgroups.
Frequency distributions of pain at rest and pain with activity were summarized and
chi-square analysis was usrd to identib any relationship to diagnosis (MED vs. SED).
Summary statistics for pain intensity (VAS) for both pain at rest and pain with activity were
performed and subgroups were compared with a 2-sample t-test.
Relationships between the outcornes from impairment and disability domains were
studied with Pearson correlations ( r ).
RESPONSE S U M M R Y
Fi@-three subjects with epiphyseal dysplasia were identified from the HSC's Centre
for Heritable Connective Tissue Disorders database as eligible to participate in the study
within the one-year time frame. Twenty-eight of these subjects (53%) had a diagnosis of
MED; the remaining 25 subjects (47%) had a diagnosis of SED. A total of 28 subjects
participated in the study, representing a response rate of 53%. No subjects were excluded
from the study. Eleven of the 28 respondents (39%) were patients with MED. The
remaining 17 subjects (61%) were subjects with SED (Table 1).
Table 1. Distribution of respondents and non-respondents.
1 Renpoodents ( Non-responden ts
I SED l 17 I 8 l 25 l
Total
MED
Mean age of the respondents (n=28) at the time of examination was 12.9 years of age
(SD 4.9, with a range of 5.1 to 19.7 years of age. There was a mildly significant difference
in age between the MED and SED respondents (p = 0.05) with the SED subjects presenting
as slightly older (approximately 1 SD) (Table 2).
11 17 28
Table 2. Mean age and standard deviation (SD) for respondents and non- respondents.
Respondents 1 Non-respondents
When tested for significant differences between the respondent and non-respondent
groups, no statistical differences emerged wiih respect to age (p = 0.8 1) (Table 2) or gender
(xZ= 0.08, p = 0.80) (Table 3), suggesting that the sample was largely representative of the
population in terms of these characteristics.
Table 3. Cender distribution between respondent and non-respondent groups.
MED (Il)
SED (17)
The ratio of males to females was higher for the overall ED sample (1.8: 1 .O). In
particular, there was a higher male to female ratio for the MED sample (4.5: 1 .O) in
cornparison to the SED sample (1.1 : 1). When a chi-square test was performed between the 2
subgroups, this was not statistically significant (X= 2.4, p = 0.12) (Table 4).
10.9
(SD 4.1)
14.2
(SD 4.3)
Mate
Fernale
13.1
(SD 3.9)
13.5
(SD 5.0)
Respondents
18
10
Non-respondents
17
18
p Value
0.80
A chi-square analysis, however did dernonstrate a larger number of MED subjects in
the non-respondent group (A?= 4.4, p = 0.04) suggesting MED patients were less likely to
participate in the study than SED patients (Table 1). The mean non-respondent length of
Table 4. Gender distribution for MED and SED respondents.
time since attending orthopaedic clinic was 3.1 years for the ED group collectively (3.6 years
and 1.9 years respectively for patients with MED and SED). There was a statistically
significant difference in time since last visit to orthopaedic clinic between the respondent and
non-respondent groups (Table 5).
MED
SED
Table 5. Mean length of time since last visit to orthopaedic c h i c for respondents and non-responden ts.
p Value
p value Male
9
9
Res pondents
(mean length of time)
Female
2
8
Non-respondents
(mean length of time)
MED
SED
0.9
1.4
3.6
1.9
*O.OOO 1
0.52
RETROSPECTIVE DATA SUMMARY
The patient characteristics for the cohort are surnmarized in Table 6. Fifty percent of
the ED population (14128) had undergone orthopaedic surgery by the time of their physical
assessment in the study. All surgeries occurred more than one year prior to the time of the
assessment, with the exception of one patient whose surgery was more than 6 months but less
than 1 year fiom the time of'assessrnent. A chi-square test did not indicate a relationship
between diagnosis (MED or SED) and the likelihood of surgery (x* =1.35, p = 0.25).
The most common surgery for the ED population was an innominate osteotomy
(36%). There was a similar distribution of this surgical procedure amongst the 2 subgroups
when analyzed with a chi-square test (x2 = 0.003, p = 0.95). SED subjects were more likely
to have additional surgeries such as foot surgery (x2 = 3.02, p= 0.08) which included
procedures such as clubfoot repair and calcaneal osteotomies. One SED subject had
undergone a bilateral tibia1 osteotomy, while 2 other SED patients had undergone hip
replacements. Associated anomalies (myopia, odontoid hypoplasia, cleft palate,
sensonneural hearing loss) were limited to the SED population. Only 18% of the ED
population presented with scoliosis, none of which required bracing or surgery.
Table 6. Summary of patient characteristics derived from the medical record.
VARIABLE ED (TOTAL)
MED SED
I - - - -
Surgical Procedure 1 l4
1 Innominate Osteotorny 1 I Foot Deformity ( 1 )* 1 I Foo t Surgery 1 I Tibial Osteotomy 1
I Tibial Valgus (1). 1 24
I Bi-partite Patella 1 Cervical Stenosis (1)'
I Scoliosis I I Spinal Fusion l I Myopia (1)* 1
1 Cervical Myopathy (4). 1 2
I CleR Palate (1)' 1 1 Sensorineurnl Hearing Loss (1). 1 4
Ambulation Aid (1)' 2
*Misshg Values
IMPAlXMENT IiMEAsURES
A titlt ro~ometric Indices: Evaluution o f Hekht and Weipht
MED and SED 2-score distributions of height for age (HA), weight for age (WA) and
weight for height (WH), according to Frisancho's (1990) classifications for the evaluation of
growth status are presented in figures 1 through 3.
Figure 1. Height for age 2-score (HM) distributions of MED and SED subjects (n=ll and n=17, respectively) compared to NCHS reference population according to Frisancbo9s (1990) classifications for the evaluation of growth status.
Below Awrage Aw mg e Abow Awrage
Note that the MED subjects were only somewhat shorter tban average @ = 0.07) while SED subjects were markedly shorter tban average @ = 0.00001).
Fipure 2. Weight for age 2-score (WAZ) distributions of MED and SED subjects (n=ll and n=17, respectively) compared to NCHS reference population according to Frisancho's (1990) classifications for the evaluation of growth status.
- - - -- - - -
Below Awrage Awrage
36.4 1
S E O
O NCHS - - - - - -. --!
No significant differences between WAZ distributions for MED (p = 0.22) and SED (p = 0.97) when compared to the reference population.
Figure 3. Weight for height 2-score (WHZ) distributions for MED and SED subjects (n=ll and n=17, respectively) compared to NCHS reference population according to Frisancho's (1990) classifications for the evaluation of growth status.
Below Average Awrag e
Significant differences @ = 0.008 andp = 0.0001) between WH2 distributions of MED and SED subjects respectively, and NCBS reference standards.
Sixty-eight percent of the ED population fell within the below average (Z< - 1.040)
and short (2%-1.650) classification for height for age, differing significantly from the
reference population @= 0.0001). The mean height-for-age 2-score (HM) for the ED
population was -2.1 1 (SD 1.8). Summary statistics for HA, WA and WH 2-scores for ED,
MED and SED are provided in Table 7.
The MED subgroup had a mean HAZ of -0.92 (SD 1.5) suggesting average to below
average height for age at the lower end of the distribution which neared statistical
significance (p=0.07) (Table 1). The mean HAZ of the SED population -2.87(SD 1.5)
suggests significant short stature, which differs significantly fiom the reference population
(p=0.00001) (Table 1). There is a statistically significant difference @=0.002) between the
MED and SED subgroups when a 2 sample t-test is performed, indicating a greater degree of
short stature in children with SED.
Weight for age 2-score (WAZ) distributions for the ED population did not differ
significantly from the reference population @= 0.41). Given the identified short stature of
this group, a more appropnate index of nutritional status is the weight-for-height 2-score
(WHZ). In fact, seventy-five percent of the ED sample presented as above average
(+1 .036>Z<+l.640) and heavy weight (2-1.645) according to Fnsancho's (1 990)
classification. The mean WHZ score for the ED group collectively was 2.33 (SD 2.06) which
was statistically significant @ = 0.0001) when compared to the NCHS reference population.
Mean WHZ for MED was 1.77 (SD1.78; p = 0.008) and 2.69 (SD 2.21; p = 0.0001)
for SED. When comparing the 2 subgroups, there was no significant difference @= 0.25)
between MED and SED with respect to weight-for-height 2-scores.
Weight for height Z-score indices are more relevant to prepubescent children because
weight for stature is nearly independent of age only between 1 year and puberty. AAer 1 1.5
years of age, the variable timing of onset of puberty complicates the weight for height
relationship (Gibson, 1990). In order to address this issue, a separate statistical analysis of
WH2 was performed for subjects equal to or less thün 1 1 .S yean of age. Results indicate a
mean WH2 score of 2.73 (SD 1.8 1, range 1.24 to 6.5 1, median 1.69) for the ED sample,
reaffirming that this population of patients present as ovenveight for their height (p =0.0005)
when compared with the re ference population 5 1 1.5 years of age.
ED subjects presented with disproportionate stature when "sitting height-to-height"
indices were calculated and 2-scores were compared to references reported by Frisancho
(1990). Descriptive statistics of 2-score results are provided in Table 8. The mean 2-score
for the ED group for sitting height index (SHI) was 0.76 (SD 1.67) which differed from the
reference population (p = 0.023). This mean 2-score indicates that ED subjects typically
presented with a longer upper body segment compared with the lower body segment. The
mean SHI 2-score value for the MED population 0.24 (SD 1.67) did not differ significantly
from the reference population (p= 0.48) suggesting minimal disproportion among the MED
group. The SED population, however did differ significantly nom the reference population
(p=0.03). The SED subjects presented with greater disproportionate stature (longer trunks),
although due to the small sample size this was not refiected in a statistical cornparison
between subgroups (p = 0.14).
Table 7. Surnmary statistics of WAZ, HAZ and WH2 for ED(Total), MED and SED .
Anthropornetric 2-score summary
3rd Quartile
Level of Signifieance
(~50.05) Frisancho's (1!
Weigh t forAge WAZ)
Heigb t for Age ( H m
Weigh t for Height 1 WHz)
JO) classification of the evaluation of growth status: 4 . 6 5 0 (short) +; < - 1 .O40 (below average); -1 .O36 to 1 .O30 (average); > 1.036 (above average) t *Significant at p= .O5 level.
Table 8. Sitting-height-index (SHI) Z-score summary for ED (Total), MED and SED.
SHI 3 Sumniary 21c0re 1
Range of Motion
Range of motion measures were compared between the right and left sides to
establish if a difference between sides existed. A paired t-test indicated no signifiant
difference between the right and lefi side for 18 of the 19 ROM measures taken @ 2 0.05).
Wrist extension was the only ROM measure which varied fkom right to left side (p = 0.006),
indicating lower ROM values for the right wrist. Because of the overall minimal differences
between the right and lefi side, ROM values for the right side only are presented in Table 9.
In the last column of Table 9, the results of a Mann-Whitney test are presented
identiming ROM measures that Vary significantly amongst the 2 subgroups. This statistical
cornparison of subgroups is an attempt to explore the distribution of joint mobility
restrictions for further hypothesis generation.
The SED population demonstrated decreased ROM values for 6 of the 10 upper
extremity joints including shoulder flexion, shoulder abduction, shoulder intemal rotation,
elbow extension, wrist extension, and MCP flexion (ps 0.05) when compared to the MED
subgroup. ROM values for 5 of the 9 joints in the lower extremity were also significantly
reduced in the SED subgroup (ps 0.05) including hip flexion, hip extension, hip abduction,
knee flexion and ankle plantarflexion when compared with the MED group.
Table 9 (coat9d). Summary of median and interquartile joint ranges of motion (ROM) for ED (Total), MED and SED.
Joint ROM t (Refetence Values)
ED (Tot al)
Hipl Extemal Rotation (50) 28 I 40 30-5 1
Hip Abduction (50)
Hipl lntemal Rotation (40) I '" 30 1240
2 8 22 5-30
Knee Flexion (135) 1 28 135 127-143
Knee Extension 1 28
2 0-5 ( 0-10)
Ankle Dotsiflexion (20) 1 28 10 5-14
Ankle Plantarflexion (50) I '" 60 5 1-65
MED SED Mann- Whitney Test
t No significant difference between left and right ROM values when a paired t-test was performed (apan from wrist extension), therefore al1 values are of the right side only. Level of significance, **pl 0.01 ; *p< 0.05
Joint ali~nment and motion (JAM) Scores
These 20 ROM vatues were then used to establish a JAM score for each of the 9
joints: shoulder flexion, shoulder intemayextemal rotation, elbow flexion1 extension, wrist
flexiodextension, 2" MCP flexiodextension, hip fiexion/extension, hip intemaVextema1
rotation, knee flexion/extension, and ankle dorsiflexion/plantarflexion. Overall JAM scores
for each of the 9 bilateral joint movements range Born 0-72 while upper extremity JAM
scores range fiom 0-40 and lower extremity JAM scores range from 0-32. Higher scores
indicate wone outcome. Summary statistics for JAM scores are presented in Table 10.
Table 10.
JAM Summary Stntistics
Maximum Score
Median
lSt Quartile
3'd Quartile
Mean +SD - p Value
Summary statistics of Joint Alignment and Motion (JAM) Scores.
Overall JAM Summed Score U/E JAM Summed Score L E JAM Summed Score
ED patients presented with a moderate degree of joint ROM impairment with a global
JAM score of 28/72 (higher scores suggest woae outcome). The MED subgroup
demonstrated a milder degree of impairment (1 5/72) when compared with the SED subgroup
(36172), a statisticaily signi ficant difference @ = 0.000 1).
ED subjects presented with more favourable upper extremity JAM scores (12/40)
than lower extremity scores (16132) in general, suggesting greater impairment of the lower
extremities with respect to ROM and alignment. When the 2 subgroups were compared
there was a significant difference @ = 0.0001) with respect to upper extremity impairment.
The MED population appeared to have minimal upper extremity impairment (5140) whereas
the SED population demonstrated moderate upper extremity ROM impairments (16140).
Lower extremity JAM scores for the SED subgroup (20132) were significantly higher
@ = 0.00 1) than the MED subgroup (10/32) indicating severe ROM and alignment
impairments in the lower extremities for the SED subgroup.
A correlation was found between JAM scores and age (r= 0.44, p= 0.021 ). A scatter
plot revealed that JAM scores increased (suggesting worse outcornes) at approximateiy the
age of 12 for subjects. in order to control for the older distribution of children in the SED
group (rnean age 14.2, SD 4.3), a 2-sample t-test was perfonned to detect differences in mean
JAM scores between MED and SED subjects greater than 12 years of age. SED subjects
continued to present with higher JAM scores than the MED group when the two groups were
compared with subjects greater than 12 years of age @ = 0.02).
Figure 4. Scatterplot demoastratieg isereasing JAM scores (iodieatiog worse outcornes) after 12 years of age.
AGE
Surnmary statistics for (i)overall, (ii)upper extremity and (iii) lower extremity
strength Z-scores are presented in Table 1 1. When muscle strength was tested in 10 upper
and lower extrernity muscle groups, ED subjects demonstrated significant strength
impairments @ = 0.0001) when compared to the reference population (Backman, 1989).
SED subjects were significantly weaker @ = 0.02) than the MED subjects with a global
mean 2-score of -2.09 (SD 0.76) compared to -1.36 (SD 0.78). When MED and SED upper
extremity 2-scores were compared, a p value of 0.07 suggested near statistical significance,
with the SED group presenting with greater upper extremity strength impairments. A more
statistically significant finding (p = 0.02) emerged when lower extremity 2-scores were
compared between groups, indicating greater lower extremity weakness arnong SED
subjects. Both upper and lower extremity strength were significantly decreased (p = 0.0001)
when compared with the reference population (Backman et al., 1989).
Table 12 includes summary statistics of Z-scores for each of the 10 muscle groups
tested. When individual muscle groups were analyzed for differences between the 2
diagnostic groups, the SED population appeared weaker with respect to shoulder abduction
@ = 0.035), hip extension @ = 0.004), hip abduction ( p = 0.009) and knee extension @ =
0.045) with a level of significance of ps 0.05.
Table 11. Summary statistics for overall, upper extremity and lower extremity mean strength z-scores.
Strength Z-score
Summary
Median
lSt Quartile
3rd Quartile
Mean + SD -
P Value
Overall Mean Score U/E Mean Score ED I MED 1 SED 1
L/E Merin Score
Grip strength was also weak in al1 subjects testai. The mean z-score for right gr@
strength among the ED population was -2.57 (SD 1.37) and -2.05 (SD 1.46) for left grip
strength. When the subgroups were analyzed for differences using a student's t-test, there
was no significant difference in either right or lefi grip strength (p= 0.60 and p= 0.49
respectively). Both nght and left grip strength were significantly weaker (p = 0.00001)
compared with the reference population (Mathiowetz et al., 1986). Grip strength 2-scores
are summarized in Table 1 3.
Table 12.
Strength Zscore
Summary Part 1
Dysplasia
la Quartile
3d Quartile
p value
Strength z-score summary for 10 upper and lower extremity muscle groups.
Elbow Flexion Elbow Extension Shoulder ABDuction Wrist Extension Hip Extension
Table 121cont9d) Strength z-score summary for 10 upper and lower extremity muscle groups.
Strength z- score
Summary Part ll
Dysplasia (0)
Median
1" Quactile
p value
Hip Flexion Hip Abduction Knee Flexion Knee Ex tension
Table 13. Right end left grip stnagtb z-scorcsumanry statisties.
Grip Strength 2-score
Summary
Dysplasia (n)
Median
lSt Quartile
3"' Quartile
a Value
(RI G r i ~ Streneth a) Grip Streneth
Pain
When subjects were asked to report on pain, 32% (n= 9) of the combined ED group
reported pain at rest. A greater proportion of subjects with SED (35%) reported pain at rest
than MED subjects (27%). A small Chi-square value (x2= 0.2, p= 0.657) however, did not
indicate a significant difference between the 2 subgroups with respect to reports of pain at
rest.
Eighty-two percent of the combined ED group (A= 23) reported pain wiih activity,
with 94% of SED subjects (n= 16) reporting pain with activity as compared with 63% of
MED subjects (n= 7). Chi-square analysis resulted in significant findings (x2 = 4.2 ; p =
0.04) suggesting a greater proportion of SED subjects reporting pain with activity. Table 14
surnmarizes this information.
Table 14. Summary of subjects' report of pain nt rest and pain with activity.
n Pain
Summary Pain a l Rest Pain wfth Activity
Dysplasia ED SED ED SED
*Chi-square significant at p s 0.05.
Visual analogue scales for pain at rest were completed by 8 of the 9 ED subjects
reporting pain at rest. The mean score reported was 4.1 (SD 1.5) of a maximum score of IO.
MED subjects (n= 3) reported a slightly higher mean score (4.9, SD 1 .O) than the 5 SED
subjects (3.7, SD 1.7), however this was not statistically significant (p= 0.3 1) when a
student's t-test was performed.
Twenty-one of the 23 ED subjects reporting pain with activity completed a VAS.
The mean score reported was 4.8 (SD 2.5). Once again, MED subjects (n= 7) reported a
slightly higher VAS score (5.7, SD 1.8) tban the 14 SED subjects (4.4 1, SD 2.Q however
this was not statistically significant (p = 0.28).
Table 15.
VAS Score (0-1 01
Dysplasia (n)
Mcdian
1" Quartile
3" Quartilc
Minimum
Maximum
p value
Summary of VAS scores for pain at rest and pain with activity.
VAS with ACTIVITY
DlSABILITY
ASKD Scores
AI1 28 subjects completed the ASKp questionnaire while 27 subjects completed the
ASKc. In 4 cases children (under the age of 6) had difficulty completing the questionnaire.
Parents, therefore, served as proxy reporters in these cases. The distributions of the ASKp
and ASKc scores are shown graphicaily in Figure 5. Cornparison of medians by paired
Wilcoxan signed rank test showed that capability and performance medians were not
significantly different @ = 0.064), therefore only the results of the ASKp are presented.
Fipure 5. Boxplot figures showing the ASKc and ASKp scores for the ED population. The limits of the boxes represent the ~ 5 ' ~ and 7sth percentile values while the line ncross the box is the median value. Means are represented by the solid circles; outliers are represented by *.
Summary scores had potential ranges of 0-100 (the latter indicating full physical
function). The median performance summary score for the cornbined group was 95 (SD
18.83, range 21 - 100, mean 87.7)). MED subjects reported a median performance summary
score of 93 (SD 19.6, range 36- 100, rnean 84.9) while SED subjects reported a median
performance sumrnary score of 96 (SD 18.7, range 2 1-100, mean 89.5). This was not
statistically significant when the medians were analyzed with the Mann-Whitney test
(p = 0.572). These scores indicate mild reported disability within this population. The
descriptive statistics for each of the 9 domains of the ASKp are included in Table 16.
Comparison of medians for each of the 9 domains did not indicate significant differences
between the MED and SED subgroups @ 2 0.05).
Fieure 6. Boxplots of ASKp scores for MED and SED. The limits of the boxes represent the 2sth and 7sth percentile values whlle the Iiie across the box is the median. Means are represented by the circles; outliers are represented by *.
MED SED
Table 16: Summary statidics of ASKp, including individual domain scores.
ASKp Scores Part 1
Dysplasia (n)
Median
lfl Quartile
3d Quartile
Mean (SD)
p Value
Overall ASKp I Persona1 Care (p) I Dressing (p) l Eating and Drinking (p) Miscellaneous (p)
No significant difference in median scores between the ASKc and ihe ASKp (0.064), therefore only the results of the ASKp are presented.
RELA TIONSHIPS BETWEEN THE DOMAINS OF IMPAIXMENT AND DISABILITY
Four of the 19 Pearson correlations between outcomes of impainnent and disability
domains were significant @ 5 0.05). Table 17 is a correlation matrix summarizing this
information. The highest correlation was between the two measures of impainnent: i) height
for age and ii) strength (r = -50; p = 0.007)), indicating a maximal level of 25% shared
variance. Ten percent of the variance (R*) explained by the independent variable has been
suggested as the lower boundary in regards to that variable having an important impact on
the outcome (Bumand, Keman & Feinstein, 1990). There was also a moderate relationship
between strength and JAM scores (r = .35) indicating 12% share variance. Due to the small
sample size, this correlation only neared statistical significance (p = 0.069).
There were 2 significant correlations between the domains of impairment and
disability. These included pain at rest and disability (r = -0.44; p = 0.02) and pain with
activity and disability (r = -0.50; p = 0.02) indicating 19% and 25% shared variance
respective1 y.
Table 17. Correhtion mat& of impairment and diPPbility outcornes.
F Pearson Correlation Coefficient; Level of significance @ 5 0.05)
The pnmary goal of this study was to develop an impairment and disability profile of
children and adolescents with epiphyseal dysplasia, utilizing the conceptual h e w o r k of the
ICIDH (WHO, 1980). This study developed an impairment and disability profile of 28
children and adolescents; 17 with SED and 1 1 with MED. Clinical charactenstics of a
population of ED subjects have not been described in the past, particularly with respect to
joint mobility, strength, and pain and their impact on functional outcorne. This study was
able to identi fy and describe in detai 1 the degree and pattern of joint impairment and
malalignment, growth disturbance as well as subjective reports of pain at rest and pain with
activity. Two dramatic findings were identified in this study that have not been previously
described in the literature. Subjects with ED presented as extremely overweight (both
subgroups) and presented with marked muscle weakness. Overall, subjects presented with
moderate to severe physical impairments with surpnsingly minimal physical disability.
Despite identifying greater impairments in the SED group (including stature, joint
motion, strength and pain with activity) our findings were not supportive of the hypothesis
that children with SED present with greater disability. In fact, in some situations the opposite
was true. Subjects with mild impairment (MED subjects) occasionally reported greater
disability than SED subjects with greater impairment.
Contrary to our expectations and notwithstanding the small sample size, there were
few relationships between impairment and disability items. Four important relationships,
however, were identified. Muscle strength was related to height of subjects and joint motion
and alignment. Physical disability was related to pain both at rest and pain with activity in
ED subjects.
The following discussion comrnents on the observed results (impairment and
disability findings) and compares these findings with previous impairment and disability
research. Because no comparable studies exist to describe functional outcomes of children
with ED, results of this study are often compared to those involving the oligo and
polyarticular IRA populations. This population of patients has been chosen for cornparisons
because of their similarities with respect to early degenerative joint changes in the absence of
significant systemic manifestations and because of the increasing interest in functional
outcomes arnong this population.
Finally, there will be a discussion of the limitations and general implications of these
research findings and how they may potentially influence future research aimed at
understanding the long-term consequences of epiphyseal dysplasia. The implications of
these findings on rehabilitation practice, theory and research will also be discussed.
Retrospective review of 28 medical records indicated that 50% of ED subjects had
undergone some forxn of orthopaedic surgery by the time of their involvement in the study.
This is a slightly higher percentage of patients than reported by Hunter (1999) in a study
describing the subjective impressions of patients (or parents) regarding the results of a
variety of surgical interventions camied out among patients with varying forms of skeletal
dysplasias. In Hunter's study, 74 patients out of a total of 197 patients with
chondrodysplasia (37.6%) had undergone orthopaedic surgery related to their
chondrodysplasias. The results of Hunter's study suggested that overall, patients perceived a
high level of post-surgical improvement.
Likelihood of surgery was not influenced by a diagnosis of SED venus MED. It was
important to note that al1 subjects, with the exception of one, had surgery prior to 1 year from
the time of the assessment. The one other subject had surgery prior to 6 months from the
time of surgety but less than one year. The results of impairment measures (ie. ROM,
strength) were therefore, not reflective of an acute (ie. post-surgical) stage in their condition.
The most cornmon procedure arnongst both the MED and SED subgroups was the
innominate osteotomy. SED subjects were more likely to have additional surgeries such as
foot surgery (ie. club foot repair). Two SED subjects had undergone hip replacements
indicating seventy of hip involvement in these subjects. Interestingly, only 1 SED subject
underwent tibia1 osteotomy despite the high incidence of valgus knee deformities in both
groups. Only 2 ED subjects in the study (both patients with SED) required ambulation aids.
Consistent with what is descnbed in the dysplasia literature, associated anomalies such as
myopia, sensorheural hearing loss and cleft palate were limited to the SED subjects. The
impact of these associated anomolies on physical function (as measured by the ASK) were
considered minimal due to the infiuence of interventions (Le. visual and hearing aids) and
were, therefore, not assessed in this study.
IMPAIRMENT PROFILE
Subjects with ED presented with moderate to severe physical impairments that
included growth disturbance, decreased joint motion and a l i m e n t , muscle weakness and
pain.
SED subjects were markedly shorter and more disproportionate in their appearance
when compared to children of similar age and gender. Growth was not as significantly
disturbed in MED subjects, nor was there evidence of upper and lower body disproportion
when compared to the reference population. This is consistent with our knowledge of
multiple centres of epiphyseal involvement and subsequent growth disturbances in both the
spine and limbs among SED patients and primarily the limbs among MED patients.
Surprisingly, SED subjects presented with disproportionately long tmnks. This is not
consistent with the literature's clinical description of bbshort-trunk" dwarfism associated with
SED (Spranger et al., 1974; Wynne-Davies et al., 1985). lnterpretation of this result however
can be explained by the varying contribution of growth plates to overall growth. The distal
femoral epiphyses and proximal tibial epiphyses are most often affected in SED. The distal
femoral epiphysis contributes 40% and the proximal tibial epiphysis contnbutes 27% to the
total length of the lower extremity (Pritchett, 1993). Involvement of these epiphyses,
therefore, c m result in a greater proportion of growth disturbance in the lower extremities
resulting in our observation of disproportionately long tninks among SED subjects wiih short
stature.
Growth can have a significant influence on the health experiences o f children with
chronic conditions. The majority of the literature describing growth disturbances in the ED
population is anecdotal, although recently Haga et al. (1 998) empirically studied the
relatiotiship between stature and disease seventy in 15 Japanese adult subjects with MED.
Subjects were classified as either normal stature (near the standard value or < i SD below the
mean value when compared to the normal Japanese adult) or short (below that value). None
of Haga's MED subjects (including the short stature group) were more than 2 SD below the
mean and, similar to Our findings, were not abnomally short. Stature was not related to the
involvement of the spine or epiphyses of the long bones or wrist and hand when assessed
radiographically, suggesting that stature is not a sufficient cntena to differentiate between the
mild and more severe foms of MED (Haga et al., 1998).
Research studying the impact of short stature on normal development and
psychosocial consequences has been a popular, if not controversial topic. Previous studies
have reported a variety of educational, psychological, and social problems associated with
short stature, thus recommending the benefits of psychosocial intervention prograrns for
children with short stature and their farnilies (Finley, Croutharnel & Richman, 198 1 ; Rieser,
1992). More recently, there has been criticism regarding the methodological approach in
earlier research with short stature children (Stratford, Mulligan, Downie & Voss, 1999; Voss,
1995). Recent studies employing systematic evaluation of psychosocial functioning in short
stature children do not support the contention that short stature is generally associated with
psychosocial maladjustment in adulthood (Downie, Mulligan, Stratford, Betts & Voss, 1997;
Haverkamp & Noeker, 1998; Voss, 1995; Zimet, Owens, Dahms, Cutler, Litvene & Cuttler,
1997). These studies, however, do preclude the possibility of stature-associated
psychological stress or the need for support for short-statured children.
The majonty of the dysplasia literature dealing with the impact of short stature is
centred on the achondroplastic population. Achondroplasia (ACH) is a forrn of skeletal
dysplasia resultinp in significant disproportionate short stature. An interesting study by
Haverkamp and Noekcr (1 998) compared the ACH population to subjects with growth
hormone deficiency (GHD) when evaluating a new growth-disorder speci fic questionnaire
for parents of short-statured children. The ACH group represented a more severe
presentation of short stature with a more disproportionate appearance than the GHD group.
For ACH patients, "short stature-related daily problems and their general experiences of
being physically handicapped" were stated as the major stress factors (Haverkarnp & Noeker,
1998, p.45 1). The ACH patients were more concemed with physical restrictions in their
everyday life than the GHD patients. The study suggests that being small is more a
"psychological and social problem" for GHD patients due to the associated stigma from
peers of 'just' being short (Haverkanip & Noeker, 1998, p. 452). In contrast, ACH patients,
with their extremely disproportionate appearance as well as extremely short stature "may
provoke the stigma of being disabled, thus offering a chance of more supportive reactions"
from othea (Haverkamp & Noeker, 1998, p. 452). Interestingly, ACH patients demonstrated
increased coping efforts and strong social support in this study.
Similar cornparisons could be drawn behveen the MED and SED subgroups. Like the
ACH subjects, SED patients presented with a greater degree of short stature and greater
disproportionate appearance. The MED subjects could be compared to the GHD group with
respect to their milder degree of short stature and minimal disproportion. Like the GHD
group, the mild short stature of the MED group could potentially result in greater risk of
stigmatization in ternis of "just being short" by their peen. MED subjects may potentially
experience more social problems that differ from the experiences of SED subjects who rnay
present as more disabled and may therefore experience more supportive reactions from
others.
Despite the physical and psychological concems sumunding short statue, treatment
for subjects with skeletal dysplasia is limited. Growth hormone therapy is not a reasonable
option in skeletal dysplasia (Burren & Werther, 1996). With limited treatment options,
psychosocial intervention from a social work perspective may be valuable in helping children
and adolescents with ED develop healthy coping mechanisms, a positive self image and
realistic vocational goals (Finley et al., 1981; Rieser, 1992). This however, continues to be a
challenging area of research that requires improved designs that would include sensitive and
speci fic techniques for anal yzing and comparing quality of li fe in short-stature children and
adolescents with ED (Stratford et al., 1999; Haverkarnp & Noeker, 1998).
Measures of weight in relation to height allowed for a better understanding of the
nutritional status of ED subjects utilizing anthropometric indices. A dramatic finding (not
described in the literature) was how overweight these individuals were for their height.
These findings were compared to nutritionai studies involving patients with oligo and
polyarticular JRA. Unlike the ED group, the oligo and polyarticular JRA subjects had
normal nutritional status (Knops, Wulffiaat, Lodder, Houwen & de Meer, 1999). The
absence of significant weight gain among the JRA population may related to the
inflammatory nature of the disease, wbich is not characteristic of ED.
Excessive weight gain is a concern for ED patients in light of the early degenerative
joint changes that occur in subjects with chondrodysplasia. The resultant effect is additional
loading of joints predisposed to early degenerative changes and arthritis. The reason for the
overweight presentation of ED patients is not likely associated with the disease itself and is
therefore not readily explained. Weight gain could potentially be attributed to a sedentary
li festyle. The presence of pain with activity or joint restriction could account for limited
physical activity in ED patients, although Our study did not identify a relationship between
weight and joint motion and alignment. Although our study did not investigate physical
fimess levels in children with ED, similar studies in children with polyarticular juvenile
rheumatoid arthritis have been reported (Klepper, 1992). The results showed that children
with pol yarticular IRA were less physically fit than nomally active (noncompetitivel y
athletic) children of the same sex, age, and size. However, the study also f o n d that there
was no statistically significant relationship between increased disease severity and physical
fitness levels. Multiple factors (ie. limitations imposed by parents, schools) may possibly
account for low fitness levels seen in children with chronic arthritic disorders such as ED and
RA. This can potentially compromise the functional status of these children and in the case
of the ED population, could possibly contribute to increased weight gain.
In light of this information, ED subjects may benefit from nutrition counselling and
formalized physical conditioning regimes that could be part of a standardized medical
protocol aimed at improving levels of physical fitness and promoting weight control.
Joint ROM and Alhment
Although the literature describes irregularity of the joint surfaces and premature
degenerative joint changes as a clinical feature of ED, no studies describe in detail the pattern
or degree of upper and lower extremity joint impairment. The results of JAM scores in this
study indicate moderate to severe impairments of joint ROM and alignment in ED subjects,
predominantly of the lower extremities with increasing severity with age. The MED and SED
subgroups differed in their presentation; subjects with SED appear to be more severe,
particularly with respect to upper extremity joint motion and alignment. MED subjects liad
minimal upper extremity joint impaiments and milder lower extremity impaiments.
The degree of joint restriction and malalignrnent in the ED subjects appears to be
more severe when compared to the joint findings in a study involving polyarticular JRA
subjects. Van der Net et al. (1996) used the JAM scale to assess joint ROM and alignment
abnormalities of 23 subjects with polyarticular JRA (van der Net et al., 1996). The median
JAM score was 15% of the worse maximal score, indicating mild to moderate joint
impairment. Median JAM score for the ED subjects demonstrated moderate to severe joint
impairment (median JAM score representing 38% of the worse maximal score). The MED
group faired slightly worse (19%) with respect to JAM scores when compared to the
polyarticular JRA subjects described by van der Net (1996). The SED group was more
severely impaired with respect to joint motion and alignrnent (54% of the wone maximal
score).
ED subjects presented with marked upper and lower extremity muscle weakness,
which is consistent with other research findings where children present with degenerative
joint disease (Fan, Crouthamel & Richman, 1998; Lindeharnmar & Backman, 1995).
Lindehammar and Backrnann (1 995) studied muscle strength in children with juvenile
chronic arthntis and found that muscle weakness was more pronounced in muscles near an
inflarned joint, however there also seemed to be a smaller generalized muscle weakness as
well.
Once again, SED subjects demonstrated a greater seventy of upper and lower
extremity impairments when compared to MED subjects with respect to strength. Specific
muscle groups that were identified as weaker in the SED subgroup included shoulder
abducton, hip extensors, hip abductors and knee extensors. There are probably many factors
that reduce strength among patients with ED. Although it is not possible to draw conclusions
about the causes of muscle weakness From Our study because of the limited sarnple size, one
can postulate several potential causes. They include (i) reflex inhibition due to painhl joints,
(ii) reduced physical activity resulting in generalized weûkness a d o r (iii) joint restriction or
malalignment interfering with muscle activity. Consistent with this last point, Our study
identified a moderate correlation between joint motion and alignment and strength (although
due to the small sample size this was not statistically significant). These results suggest that
as joint ROM and alignment deteriorate, so does strength. Previous research quantifying
muscle strength in children has also identified the important contribution of height in
determining muscle strength (Molnar & Alexander, 1973) as well as previous level of
activity (Alexander & Molnar, 1973). Therefore, we would expect that children with ED
(particularly children with SED) would have a biomechanical disadvantage in strength due to
their short limbs. In fact, this was reflected in our study with a statistically significant large
correlation between height and strength in ED subjects. Although this was not assessed in
this study, deceased levels of activity may further compromise strength in these subjects.
Subjects with ED presented with very weak grip strength with consistently low 2-
score distributions similar to upper extremity strength values already described. Grip
strength impairments are consistent with clinical descriptions of epiphyseal involvement of
the small bones of the hand (brachydactyly) in ED patients. Both MED and SED subgroups
presented with marked differences in grip strength compared to the reference population
(Mathiowetz et al., 1986).
Muscle w e h e s s has not been described in the ED literature, nor has the
consequences of muscle weakness on physical disability. When the literature was reviewed,
the oligo and polyarticular JRA populations were shown to demonstrate a moderate
relationship between muscle strength and functional performance (Fan et al., 1998). Fan et
al. (1998). reported a moderate correlation (r = -0.48, p = 0.03) between strength
(standardized quadriceps torque) and function (CHAQ) in a sample of 20 polyarticular JRA
females between the ages of 6 to 16. Surprisingly, upper and lower extremity strength and
grip strength did not correlate with physical finctioning in Our study. Despite the extent of
muscle weakness in ED subjects, disability was very mild. In Fan et al.'s (1998) study of the
relationship between strength and function in fernales with JIU, subjects demonstrated good
functional ability as measured on the CHAQ, but poor performance on a 50 m run.
Surprisingly, over 60% of the girls who scored normal (O) on the Disability Index of the
CHAQ scored in the lowest category on the 50 m run. Poor performance on the 50 m mn,
even in girls who showed no disability on the CHAQ, suggests that children with JRA may
have difficulties in physical education, recreational activities, and organized sports even
when they do not report any difficulty with activities ofdaily living. Fan et al. (1998)
discussed the limitations of using the CHAQ alone, suggesting that the CHAQ may not
adequately measure disability in recreational sports. The same may be me for the ED
subjects within Our study. Similarly, the ASK alone may not adequately rneasure the impact
of the disorder in recreational sports and more strenuous activities. A srnall ceiling effect has
been described by the author of the ASK (Young, 1997). Subsequently, an observational
functional performance test may have been more informative on the impact of muscle
weakness on physical function in this study than the ASK questionnaire alone.
Patients with ED may be predisposed to muscle weakness due to the many factors
described above. Although information regarding the efficacy of strengthening prograrns is
limited, they are widely accepted as necessary approxhes in rehabilitation programs for
children with chronic diseases such as JRA (Klepper, Darbee, Effgen & Singsen, 1992;
Klepper, 1999; Oberg, Karsznia, Andersson & Lagerstand, 1994). Little information
presently exists on the rehabilitation of patients diagnosed with chondrodysplasia. Results
from our study indicate the need for a physical conditioning program that would include
appropriate upper and lower extremity strengthening exercises for patients diagnosed with
ED.
Pain has been described in general t ems within the ED literature, with presentation
described as localized to weighi-beanng joints such as the hips, h e e s and low back
(Andersen et al., 1988; Cole, 1 993; Ingram, 1 992; Spranger et al., 1974; Wynne-Davies et al.,
1985). In our study, ED subjects reported moderate to severe pain, with pain more ofien
reported in the lower extremities. Pain with activity was more common among the collective
ED group than pain at rest, which was reported by a small nurnber of individuals (n = 9).
Pain at rest was primarily described as pain with prolonged sitting or standing or moming
stiffbess. There were similar proportions of MED and SED subjects reporting pain at rest,
however there was a significantly greater proportion of SED subjects reporting pain with
activity. Pain was usually descnbed in the hips, knees and ankles lasting for several hours
afler the acîivity. There were no sigdicant Merences with respect to intemity of pain when
a VAS was used to measure pain at rest and pain with activity. Unlike other patterns of
impairment, the SED subjects did not report greater intensities of pain at rest or pain with
activity. This could possibly be attributed to SED subjects accommodating their activities
(ie. sports and recreational activities) due to their impairments and adapting to their
experiences ofjoint pain fiom an early age.
The subjective report of pain is oRen the predisposing reason for subjects to attend
the orthopaedic clinic at the HSC and may therefore be more severe among this sample of
subjects. When attempting to compare the extent and severity of pain reports in the ED
population to the polyarticular JRA population, difficulties arise. Unlike the ED population,
pain in the J I U population has primarily been associated with joint inflammation, although
problems with the systematic evaluation of pain in the IRA population have also been
identi fied (Ilowite, 1992). In a study by Ilowite, Walco & Pochaczevsky (1 992), the degree
of joint inflammation was only one factor of several contributing to the amount of pain
experienced by children with juvenile rheumatoid arthritis. The results of the study
suggested that correlations of patient pain intensity ratings and joint temperahire (indicating
joint inflammation) were only significant in younger children. The study highlights the need
for future research that can identify the psychologic and socioenvironmental variables that
influence pain in IRA. This information may also be of assistance in understanding
additional variables that may similarly influence pain in ED subjects. Identification of these
variables was not undertaken in this study.
One of the few reiationships between impairments and disability identified within our
study occurred with pain as the impairment outcome. Pain at rest and pain with activity
appear to have a large impact on physical fùnction in subjects with ED. This is consistent
with a previous study that identified pain as the best predictor of fhnctional performance
(CHAQ scores) in females with JRA when strength, pain and joint count were assessed for
their relationship with function (Fan et al., 1 998). These relationships between pain and
physical fùnction highlight the importance of pain assessrnent and pain management among
patients with ED.
DISABILITY PROFILE
ASKP Scores
Children and adolescents with ED reported mild physical disability. Contrary to our
expectations and notwithstanding the small sample size, there were few relationships
between impairment and disability items. Interestingly, some subjects with milder forms of
MED (minimal impairments) reported greater disability than SED subjects with more severe
foms of dysplasia. This does not converge with the original hypothesis (based on the
disablement model) that SED subjects would have greater impairments and consequently
greater disability than MED subjects. As descnbed earlier in this paper, these were MED
subjects who were ofien asymptomatic in their early yeam and were, therefore, not diagnosed
until 5 years of age or later. As a result, they were more likely to have participated in
unlimited physical activity and were suddenly experiencing new symptoms, which limited
their ability to perfonn in these activities. Their perception of disability mey have been
greater due to the context of their previous expenences. For example, one very active 5-year
old child with MED was an avid soccer player who suddenly began experiencing severe pain
in his hip, limiting his ability to participate in soccer. In this situation, the mother semed as a
proxy reporter for her child. In filling out the questionnaire, she reported that her son was
experiencing greater difficulty keeping up with friends and participating in his regular level
of activity, therefore reporting increased disability on the questionnaire.
Children with SED, on the other hand, are oflen diagnosed at a younger age due to
early musculoskeletal symptoms including pain and altered gait patterns as well as short
stature. These children may have always been limited in their ability to participate in
physical activities and may therefore have accommodated their activities to suit their
impairments. Their expectations, therefore, may differ based on these experiences. SED
subjects, therefore, may report similar or less disability than described in the example of the
MED subject, even though they are unable to participate in sports and regular peer activities.
Van der Net et al. (1996) found similar results when studying the relationship
between impairment and disability in children with polyarticular SRA (van der Net et al.,
1996). Despite moderate impairment findings (JAM scores), children with polyarticular JRA
showed minimal functional limitations (CHAQ scores). M e n attempting to account for this
finding, the authors questioned whether the CHAQ was the best instrument to use in the
developing child. In our study, the ASK (like the CHAQ) may not account for motor
development as well as psychosocial development in the younger children (i.e. 5-7 years of
age). Also, the poor correlation between impairment and disability may be partly explained
by the capacity of children to compensate for their impairments. Again, the SED subjects in
this study who may have had to compensate and adapt to their physical impairments fiom an
early age might have demonstrated this. Interestingly, an additional finding From paediatric
studies in the JRA population is that behavioural adaptation is above average in these patients
(van der Net, 1995). Similar results were found in a study of impairment and disability in
children with osteogenesis imperfecta (01) (Engelbert et al., 1991). In Englebert et al.'s
study (1 999, social function was better developed in younger children (5 7.5 years of age)
with more severe types of 01, possibly to compensate for their disability. Whether this is
also true amongst other chronic conditions, such as ED, has yet to be studied.
ANAL YSIS OF RELA TIONSHIPS BETWEEN IMPAIRMENT AND DISABILITY
The focus of this study was on musculoskeletal impairments and physical disability.
Consistent with our knowledge of impaiments, some relationships did exist among
impaiments (ie. ROM and strength); however, disability outcornes did not correlate well
with more serious impairments (ie. the relationship between JAM scores or strength and the
ASKp). The small numbers of significant correlations are certainly influenced by the small
simple size in this study.
This lack of relationship between the domains of impairment and disability may be
fùrther explained by the influence of what is referred to as "extemal factors" in the disability
literature. Badley (1995) addresses concems raised by the representation of the ICIDH
model as a simple linear model. Badley (1 999, Verbrugge & Jette (1 994) discuss the
classification of external factors within the disablement process. Verbrugge & Jette (1 994)
describes these external factors as "interventions" which are sub-divided into intra-individual
interventions (psychosocial attributes which may include motivation, self-perception, coping,
activity accommodations) and extra-individual interventions (medical care and rehabilitation,
external supports).
Recently, Wai (1999) described similar results where no relationship was found
between spinal deformity (impairment) and overall physical disability in children with spina
bifida and scoliosis. The study was able to identify many extemal factors referred to as
"intermediate steps" that may have explained why a specific impairment was not directly
related to the latter steps of the ICIDH pathway. In spina bifida subjects, sitting imbalance,
altered hand function, psychological factors (ie. motivation and self-image) and
physiotherapy were al1 examples of intermediate factors which may have altered the outcome
of disability along the ICIDH pathway. Analysis of these extemal factors led to the
conclusion that spinal deformity was not related to physical disability in children with spina
bifida and scoliosis (Wai, 1999).
Our study of the relationship between physical impairment and disability in chi ldren
and adolescents with ED did not include measures of extemal factors for analysis. The
inclusion of these extemal factors in future research may be necessary to increase our
understanding of the consequences of ED on physical function. Psychosocial evaluation
utlilizing instruments that assess important issues such as scholastic competence, social
acceptance, athletic competence, physical appearance and general self-worth may be
worthwhile. Infornation gained from these evaluations may be helpful in developing a more
comprehensive understanding of the consequences of physical impairment on functional
outcome.
METHODOLOGICAL ISSUES AND LIMITATIONS
Although efforts were taken to ensure a sound scientific research project, some
methodological limitations exist. These methodological issues and limitations will be
discussed in further detail.
Because epiphyseal dysplasia is a rare hentable comective tissue disorder, the
number of subjects available to participate in the study was small. At the onset of the study,
a response rate of 75% was anticipated based on i) previous subject willingness to participate
in genetic research within the CHCTD ii) efforts to make study participation convenient for
subjects by collecting the data during scheduled orthopaedic c h i c visits iii) the absence of
invasive procedures or harmful effects iv) the assumption that the study addressed relevant
and meaningfûl issues to families and patients with ED. The number ofrespondents,
however, was unexpectedly low, with a response rate of 53%. Although the small numbers
limit the power of this study, the value of identiS?ng trends in a 'bpopulation" study such as
this cannot be overlooked. Relatively speaking, a cross-sectionai study of 28 subjects with
ED is large when considering the likelihood of this condition.
A sample of convenience of al1 eligible subjects with MED and SED from the HSC's
CHCTD database between the ages of 5 and 20 years of age was used for sample selection to
maximize the number of subjects for the study. The nature of our tertiary care centre would
suggest a bias with respect to disease seventy, since this centre would typically see the more
severe cases of ED. When non-respondents were reviewed, subjects with MED were under
represented in this sample. Non-respondents, particularly MED subjects, had less contact
with the orthopaedic clinic in Our tertiary health care centre. This would imply that subjects
were less involved with respect to disease severity and therefore, may have had less incentive
to participate in the study. The subjects in this study are, therefore, more representative of
ED chi ldren with severe disease activity.
SED subjects who participated in the study were older (approximately 1 SD) than the
MED subjects. This age difference has implications for outcomes. Because arthritic changes
are progressive in nature, age can be a confounding factor when interpreting JAM score
results. In fact, a significant correlation was identified between age and JAM scores. Efforts
were therefore made to control for this confounding factor; SED subjects continued to
present with worse outcomes with respect to their JAM score, even when subjects 12 years
and older were compared. This suggests that type of diagnosis (SED) has an important
impact on joint limitation in addition to age.
Impairment and Disdilitv Tools
Due to the limited availability of nom-referenced strength values for children, this
study was limited to the results published by Backrnan et al. (1989) when companng strength
of study subjects with noms. This was not an ideal situation since these noms are reflective
of a relatively small sample size of Scandinavian children (n = 2 19), between the ages of 3.5
to 15 in which strength noms are presented within 6 age-related cut-off points (3.5-5,557,
7.5-9,9511, I 1.5-1 3 and 13.5 to 15). This may not be an accurate reflection of strength
noms for our population under study. In response to this concem, 10 healthy subjects with
no history of musculoskeletal complications were tested using the NMMT. When these
subjects were compared to Backman's reference values, strength values were more likely to
be consistent when the healthy subjects fell at the high end of the age cut-off point.
(Example: A 9.2 year old female would demonstrate similar strength scores to the reference
values for her age category, however a 7.5 year old healthy female would have lower
strength values when compared to the reference values.) The reference values descnbed by
Backrnann (1 989) might be considered high when compared to North Amencan children,
although this would not account for the significant differences in strength demonstrated in
the ED population. Interestingly, the grip strength z-scores for the ED population were also
significantly lower when compared with the reference values descnbed by Mathiowetz et al.
(1986). The alternative option of manual muscle testing (MMT) described by Daniels and
Worthingham (1 986) did not present as a better alternative. We are, therefore, left with the
conclusion that ED subjects are mily weak.
The diubiliiy tool used in this study, the ASKp, provided a subjective report of
physical function. Although the scale was developed for children 5 to 15 years of age, the 5-
year old subjects often required proxy reporting by their parents. Two such cases were MED
subjects who presented with minimal to moderate impairments, yet their ASKp was low
(indicating greater disability) when compared to other subjects. This discrepancy could be
explained by a difference in perception of the impact of the disease by children and parents,
with parents possibly reporting greater disability.
The effect of growth and developrnent on the scores of the ASK has not yet been
established. Comments fiom parents of younger children suggested that it was difficult to
accurately answer al1 the questions because of the age of the child. The concem of age-
appropriate items in the questionnaire (ie. persona1 hygiene and dressing) was raised for
some of the younger children.
CONCLUSION
This study is the first of its kind to apply the framework of a disablement mode1 to a
population of children and adolescents with epiphyseal dysplasia (ED), in an effort to better
understand the impact of the associated musculoskeletal disorders on physical function. As a
result, we have developed an impairment and disability profile for 28 children and
adolescents with a more severe form of epiphyseal dysplasia, identifjhg significant
differences amongst the 2 subgroups- MED and SED. Our findings suggest that despite
moderate to severe physical impairments, these subjects demonstrated surpnsingly minimal
physical disability. There were few relationships between impairment and disability items.
Although these results should be interpreted with care, realizing their limited generalizability,
the information can be viewed from the perspective of a pilot study identiQing potential
issues and treatment resources required by this population. This study identified several
physical impairments mong the ED group that could potentially be addressed from a
multidisciplinary perspective when considering the comprehensive care of these patients.
Issues of short stature and altered physical appearance have been identified in the literature as
potential sources of psychosocial stressors, requiring psychosocial intervention aimed ai
teaching coping mechanisrns. Ovemutrition is a concem for this population suggesting
potential bene fits of nutritional counselling. Physical rehabilitation would address
musculoskeletal issues (joint mobility, strength and pain) ensuring appropriate exercise
prescription and education regarding the benefits of appropnate physical activity to prevent
possible longterm health problems (ie. obesity) due to poor physical fitness. Despite the poor
correlation between impairment and disability, these impairments remain significant thus
warranthg interventions geared at minimizing the consequences of this chronic disorder. At
present, patients with ED are seen pt=imarily in an orthopaedic c h i c setting, oflen oniy when
musculoskeletal problems arise. The physical impaiments identified in this study would
suggest important benefits o f a regular, comprehensive care clinic for children and
adolescents with epiphyseal dysplasia.
FUTURE RESEARCH
This study was able to identiQ an impairment and disability profile for children and
adolescents with more severe forms of ED. It may not be representative of al1 foms of ED
due to the variability of expression of the disease, as is often the case in autosomal dominant
conditions. Future research with a larger, more comprehensive sampie size based on familial
history and including ED subjects who may not be familiar to an acute tertiary hospital
setting would provide a profile with improved generalizability.
A cross-sectional study such as this is limited in that it provides a snapshot in time
and thus does not indicate causality (Streiner, Norman & Munroe-Blume, 1989). Ageing has
an important impact on disability. Although there was minimal physical disability in this
sarnpie, we are not able to predict disability among patients with ED as they age. A study by
Treble et al. (1990), detemining the natural history of the hip in MED patients illustrates this
point. Despite the establishment of hip incongruity in childhood as a primary predictor of
premature osteoarthritis, even congruous hips were prone to premature osteoarthritis by 30
years of age (Treble, 1990). In the future, a longitudinal study would, therefore, provide
important information regardhg impairment and disability outcomes among ageing patients
with ED. The result of this knowledge will provide patients, families and health care
providers with a better understanding of the long-term impact of ED on physical function.
As we have seen in this study, disablement research in rehabilitation provides a
unique and valuable perspective in understanding the consequences of chronic disease at the
level of the i ndividual. This study, however, recognizes the limitations of existing
disablement models such as the ICIDH (WHO, 1980) and identifies the challenges inherent
in disability research. The relationship between impairment and disability is more complex
than our present undentanding of it. There is increasing evidence to suggest that treatment
of impairments may not specifically lead to improved or meaningful physical function
(suggesting decreased disability), ofien challenging medical and rehabilitation professionals
to identi fy at what level intervention should in fact be directed. Refinement of disablement
models will require the development of more sensitive tools to evaluate the complex
relationship between impairment, disability and handicap. Subsequently, we will have an
improved understanding of the needs of patients with chronic disorders, such as ED, and be
able to provide the necessary intervention, the appropriate resources as well as improve our
ability to evaluate treatment effectiveness and efficiency.
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APPENDUC 1: ETHICS APPROVAL
APPLICANTS: Ms. R. Damignani, Drs. E. Badley, N. Young, W. Cole
PROJECT TITLE: Impairment and Disability Associattd with Epiphyd Dyspiasia in Chrldren
FILE NUMBER: 981192
MEMBERS OF THE BOARD*: Dr.A. Moore, Chair Dr. B. Sicvcns Dr. M. Rossi Dr. A. Taddio Dr. D. Bagli Ms. S. Serena Dr. B. McCRndle Dr. M. Crawford Ms. S. Doyle
Ir. M. Deanis Hs. f. Clarbon &S. B. Benoliel ils. M. Rowell Ir, C* Fmdin*, Mli Ir. S. Banichel Ir. A.Feigenbaum Ir. L. Komar
*Meeting may not have k t n iutcndcd by ail mcmbcrs.
I agrec to cany out the proposrd research inoolving huma~ subjects in accordance with the protocot approved by the Research Ethics Board usàng the approoed-. oonsent formls, f shall no t i i the dtpartmentldittision chief and the Research Ethics Board prior to implmentirig any modifications in the protocol and of atry adverse or unerpected mmts as soo
SIGNATURE (INVEsTxGAToR) DATE H? , o f .
I agrec to moniior the protocol on an ongolng bas&, and to nollfL the Resrarch Ethics Board as approprtrrte.
SIGNATURE A. f . ~ +7 te, mr
(DEPARTMENTIDMSI0iWEA.D) -S&,&** DATE !o. tqa*
The Research Ethics Board of the Hospital for Sick Children has reviewed and approved the above-named project.
DATE OF APPROVAL
EXPIRY DATE MAY - - #n#
APPENDIX 2: INFORMATION LETTER TO PARENTS
Date
Name of Family Address
Dear Mr. and Mrs. ,
Borie dysplasias are fairly uncornmon, inherited conditions that affect bone growth and development. Children with these conditions may develop problems in muscles and joints that could possibly affect their ahility to perform physical activities. Unfortunately, there is little information about this. In an effort to increase our understanding of these conditions and improve the health care of children, a study is currently taking place at the Hospital for Sick Children. From this study, we hope to identify what some of these problems are and how they may affect the performance of day-to day physical activities.
The study will include children between the ages of 5 and 19 years of age, with multiple epiphyseal dysplasia or spondyloepiphyseal dysplasia. The participants will undergo one physical assessment and will fil1 out a 2-part questionnaire. The cost of HSC underground parking or public transportation will be provided for participants from a research gant. More detailed information about the study is provided in the attached "Clinical Information Form". Once the study is complete, results may be made available to interested participants.
If you would like to participate in the study or would like more information about the study, please feel free to contact our office at 41 6- 8 13- 4902.
Thank you for taking the time to read this information.
Sincerely,
Ola Ostrowski, secretary to Dr. W.G. Cole, MBBS, MSc,PhD,FRAC,FRCSC Centre For Heritable Comective Tissue Disorders Hospital for Sick Children
CLINlCAL INFORMATION FOR PARENTS
Title of Research Proiect: Impairment and disability associated with epiphyseal dysplasia in children
Primaw investieator: Rita Damignani, BScPT, MSc(candidate); (4 16) 8 13-6755 (7) Co-investinatorls): Dr. Elizabeth Badley, Dr. Nancy Young, Dr.W.G. Cole
PURPOSE: Bone dysplasias are fairly uncommon conditions that result in abnormal bone growth and development. Children with these conditions rnay develop problems in their muscles and joints that could possibly affect their ability to perform physical activities. Unfortunately there is very little information about this. The purpose of this research, therefore, is to increase Our understanding of these conditions arnong patients 5 to 18 years of age. This will assist us in providing greater information and the best care for patients and their families.
WHAT WILL HAPPEN: If you and your child agree to be part of the study, your child will undergo an assessment that will occur at the time of your scheduled visit to orthopaedic clinic. If your child does not have an appointment in clinic, an appointment will be set up at a time that is convenient for you. A physical therapist will be measuring movement of several joints of the body and strength of several muscles. Measures of height and weight will also be taken. Your child will be asked to describe any pain he/she rnay have at rest a d o r any pain with activity. At the end of the assessment you and/or your child will be asked to complete a 2-part questionnaire, which describe how he/she performs various physical activities.
BENEFITS: You and your child will help contribute to and expand the current information regarding bone dysplasias. This will help to improve Our understanding of the impact of this condition, particutarly with respect to physical activities. This information rnay provide patients and their families with answers to questions commonly asked regarding the impact of this condition on children. The results rnay lead to the development of impmved treamiemts, but there will be no immediate benefit to your child's health.
RISKS: There are no known h m s associated with this study. Some individuals rnay tire
during the physical assessment of range of movement or muscle strength. You or your child rnay request rest periods at any time dunng the study. You or your child c m decide not to participate in the study at any time. This will not affect your treatrnent at the Hospital for Sick Children,
103
CONSENT FORM FOR PARTICIPANTS 16 YEARS AND OLDER
Name:
Date of Sirth:
HSC #:
Title of Research Proiect: Impairment and disability associated with epiphyseal dysplasia in children
Investipator(s): Primary Investigator: Rita Darnignani, MSc(candidate), BScPT Rehabilitation Services Hospital for Sick Children 4 16-8 13-6755
Co-Investigators: Dr. Elizabeth Badley, D.Phil., MScJ3Sc
Associate Professor, Faculty of Medicine, Dept. of Rehabilitation Science University of Toronto 4 1 6-946-2902
Dr. Nancy Young, PhD, MSc, BScPT P.O.R.T. Programme, Paediatric Medicine Hospital for Sick Children 4 16-8 13-5446
Dr. W. Cole, MBBS,MSc, PhD, FRACS, FRCSC Chief of Orthopaedics Hospital for Sick Children
Pur~ose of the Research: Bone dysplasias are fairly uncornmon conditions that result in abnormal bone growth. Children with this condition may develop problems that could possibly affect their ability to perform activities. There is very little information describing the impact of this condition on people. The purpose of this research, therefore, is to increase our understanding of these 2 conditions among patients 5 to 18 years of age. This will assist us in providing the best care for patients.
Descri~tion of the Research:
If you agree to be part of the study, you will undergo an assessment that will occur at the time of your scheduled visit to orthopaedic clinic. If you do not have an appointment in clinic, an appointment will be set up at a time that is convenient for you. The physiotherapist will be measuring motion of several joints of the body and strength of several muscles. Measures of height and weight will also be taken. You will be asked to describe any pain you may have at rest and/or any pain with activity. At the end of the assessment you will be asked to complete 2 versions of a questionnaire, which describe how you perform various physical activities.
Potential Harms Iniuries, Discornforts or Inconvenience:
There are no known harms associated with this study. By taking part in the study, you will undergo an assessment that will take approximately one hour. The physical therapist will try to make use of the usual waiting tirne in c h i c to complete the assessment. Some individuals may expenence mild discornfort or may tire during the physical assessment of range of movement or muscle strength. You may request rest periods at any time during the study. You c m decide not to participate in the study ai any time. This will not affect your treatment at the Hospital for Sick Children.
Potential Benefits:
You will not benefit directly fiom participating in this study. You will help to contribute to and expand the current information regarding bone dysplasias. This will help to improve Our understanding of the impact of this condition, particularly with respect to physical activities. This information may help health professionals answer many of the questions patients and fmilies have regarding the impact of this disorder on the person. This will also assist in deciding the most appropriate treatment for patients and evaluating these treatments.
Con fiden tialitv:
Confidentiality will be respected and no information that discloses your identity will be released or published without consent unless required by law. For your information, the research consent form will be inserted in your health record.
Participation in research is voluntary. If you choose not to participate, you will continue to have access to quality care at HSC.
If you would like to know the source of fùnding, please discuss this with the investigator.
Consent :
"I acknowledge that the research procedures described above have been expkrined to me and thut ony questions that I have asked have been arîswered to my satisfaction. I have been informed of the alternatives to participotion in this study, including the right not to participcrte and the rigltt to withdraw without compromising the qualiw of nedical care ut The Hospital for Sick Children for me and for otlier members of my family. As well. the potential harms and discomforts have been et-plainecl to nie and I a h understand the benefirs (f any) of participatirg in the research strtdy. 1 Iiow d o t I may ask now. or in the future, any questions I have abottt the stttdy or the research procedttres. f have been assureci that records relating to nie and ny cure will be kept conjidential and that no information will be released or printed tliat wortld disclose personal ide11 tity witholtt my permission unless reqtt ired by law. "
I hereby consent to participa te.
The Person who may be contacted Nome of Patient and Age about the researcli is:
who may be reached at telephone #: Sigrrat ure
(416) 813-6755 (#7)
Name of person ivho obtained consent
Signature
Date
CONSENT FORM FOR PARTICIPANTS 4 6 YEARS OLD
Date of Birth:
HSC #:
Title of Research Project: Impairment and disability associated with epiphyseal dysplasia in children
Primary Investigator: Rita Damignani, MSc(candidate), BScPT Rehabilitation Services Hospital for Sick Children 416-813-6755 (#7)
Co-Investigators: Dr. Elizabeth Badley, D.Phil., MSc,BSc Associate Professor, Faculty of Medicine, Dept. of Rehabilitation Science University of Toronto 4 1 6-946-2902
Dr. Nancy Young, PhD, MSc, BScPT P.O.R.T. Programme. Paediatric Medicine Hospital for Sick Children 4 16-8 13-5446
Dr. W. Cote, MBBS,MSc, PhD, FRACS, FRCSC Head, Orthopaedic Surgery Hospital for Sick Children
Pur~ose of the Research:
Bone dysplasias are fairly uncommon conditions that result in abnormal bone growth. Children with this condition may develop problems that could possibly affect their ability to perform activities. There is very little information describing the impact of this condition on people. The purpose of this research, there fore, is to increase our understanding of these 2 conditions among patients 5 to 18 years of age. This will assist in providing the best care for patients.
Descriation of the Research:
If your child agrees to participate in the study, he/she will undergo an assessment that will be CO-ordinated with your scheduled retum visit to orthopaedic clinic. If your child does not have a scheduled appointment to retum to clinic, a convenient assessment time will be arranged at the HSC. The physiotherapist will be rneasuring motion of several joints of the body and strength of several muscles. Measures of height and weight will also be taken. Your child will be asked to describe any pain they may have at rest and/or any pain with activity. At the end of the assessrnent your child will be asked to complete 2 versions of a questionnaire, which describe how they perform various physical activities.
Potential Benefits:
Your child will not benefit directly from participating in this study. Your child will help to contribute to and expand the current information regarding bone dysplasias. This will help to improve our understanding of the impact of this condition, piuticularly with respect to physical activities. This information may help health professionals answer many questions patients and families have regarding the impact of this disorder on individuals. This will also assist in deciding the most appropriate treatment for patients and evaluating these treatments.
Con fidentialitv:
Conlidentiality will be respected and no information that discloses the identity of the subject will be released or published without consent unless required by law. For your information, the research consent form will be inserted in your child's health record.
Participation in research is voluntary. If you choose not to participate, you and your farnily will continue to have access to quality care at HSC. If' you choose on behalf of your child to participate in this study you can withdraw your child from the study at any time. Again, you and your farnily will continue to have access to quality care at HSC.
If you would like to know the source of funding, please discuss this with the investigator.
Consent:
I acknowledge that the research procedures described above have been explained to me and that any questions that I have asked have been answered to my satisfaction. I have been informed of the alternatives to participatio~i iri this study. including the right not ro participate and the ri& to withdraw withotit compromisiiig the qmlity of medical care at The Hospital for Sick Children for my child and for other members of my family. As well, the potential liarms and discornforts have beeri explained to me and I also understand the beiiefirs (gany) of participting in the researcli study. 1 know that I niay ask now. or in the futttre. any questions I have about the study or the researcli procedtires. I have bee~i assured that records relating to my child and my child's care will be kept conjidential and that tio information will be released or printed that woitld disclose personal identity withortt niy permission itnless required by la W.
I hereby consent for my child to participate.
The Person who may be contacted about the research is:
Rita Damignani who may be reached at telephone #: 416-8 13-6755 (#7)
Nanie of person who obtairied consent.
Signature
ASSENT FORM
1 Date of Birth:
1 HSC #:
Title: Impairment and disability associated with epipbyseal dysplasia in children
Primary Investigator: Rita Damignani, MSc(candidate), BScPT Rehabili tation Services Hospital for Sick Children 416-81 3-6755 (#7)
Co-Investigators: Dr. Elizabeth Badley, D.Phil., MSc,BSc Associate Professor, Faculty of' Medicine, Dept. of Rehabilitation Science University of Toronto 4 16-946-2902
Dr. Nancy Young, PhD, MSc, BScPT P.O.R.T. Programme, Paediatric Medicine Hospital for Sick Children 4 16-8 1 3-5446
Dr. W. Cole, MBBS, MSc, PhD, FRACS, FRCSC Chief of Orthopaedics Hospital for Sick Children
Whv are we doina this studv? Children with bone dysplasias have abnormal growth of their bones. As a result, children with this condition may have problems moving joints in their body (such as a knee joint or hip joint) or may have some weakness of muscles in their arms or legs. Because of abnormal bone growth, individuals may also be shoiter in height for their age. Some children may cornplain of pain at rest or pain with activity.
This study will look at these things and will try to understand how these problems affect a child's ability to perform activities. This will help us understand what problems children may have and will help us to determine the best care for patients.
What will hamen durine: the studv? If you participate in the study, you will be seen by a physical therapist for one physical examination. Dunng the usual waiting t h e in clinic, the physical therapist will measure the movement of certain joints in your arms and legs. He/she will also measure the strength of some of the muscles in your arms and legs as well as measure your standing height and sitting height and weight. If you have pain at rest or pain with activity, your therapist will ask you to score this pain. This assessrnent will take approxirnately one hour to do. Following this, the physical therapist will provide you with instructions on how to fil1 out a two-part questionnaire that asks you questions about how you perform physical activities throughout the day.
Are there good things and bad things about the study? There are no bad things that we know about that will happen to you if you do this study. Sometimes, kids get a little tired when someone is testing their strength, however you c m ask to rest if you feel tired. You may have to stay in clinic a little longer to do this study, however the physical therapist will try to use the time that you are usually waiting in clinic to do this study.
Who will know about what 1 did in the study? Your name or address will not be givcn to anyone. Only the people doing the study will know how you did.
Can 1 decide if l want to be in the studv? If you do not want to be part of this study, that's OK, no one will be upset with you. You will still have your regular appointment with the doctor if you are here for an appointment at the orthopaedic clinic. You can ask the therapist any questions that you have. He/she will try to answer your
questions and help you to understand. If you Say yes now but change your mind later, that is OK. If you say no, it will not change the way you are treated at the Hospital for Sick Children.
Assen t:
"1 was present when read this form and gave hidher verbal assent."
Narne of person who obtained assent
Signature
Date
APPENDIX 3: Modified Joint Alignment and Motion (JAM) Scale
JAM- Upper Extremity Patient Narne: History #: Date:
Diagnosis:
Joint: LelVRight Motion Alignmnt
O I 2 3 4 2 3 4
JAM- Lowcr Extremity
Joint LctURight
Shouldcr Flexion 180
[nt. Rot 70 Ext.Rot 90
Elbow Flcxion 1 50 Extcnsion O
Wrist Flexion 80 Extension 70
2" MC Flcxion 100 Extension 35
Motion Alignment O 1 2 3 4 2 3 4
180
160
150
150
135
cl80270
<160250
c I 5 0 ~ 0
<ISO?l45
~135>130
tfip Flexion Extcnsion
Int Rot Ext Rot
<170>135
<150=20
<140~115
C14S2115
<1302100
Knee F1c.t
Cl35245
<12@40
c I15~40
4 1 5 ~ 3 0
<IO0235
o*Modificd from Parker et al.. 1988. The Value of the Joint Alignment and Motion Scale in Rheumtoid Arthtitis. The Journal of Rheunutology 15 (8). 12 12-121 5.
Ett O
Ankle Dorsitlex 20 Plant;irflexion 50
Fusion, GIH joint
Fusion/ Resorption
Fusion/ Resorption
Fusion/ 0isloc;ition
Dislocationl Fusion
Sup. C45 Migntion
Ligament 4 0 Stribility
Ligament 4 0 Instability
135
70
4 0
4 5
<135~130
<70-5
Radial Dcviation
Ulnar Deviation
Palmar Subluxationl Dcviation
>25
Palmat Sublux Ation, Ulnar Deviation
>25
C130~120
C65>55
~ 1 2 0 ~ 1 0 0
~5-20
400
<20
Valgus; c5 Instability
5-10 lnswbility
Subluxation
Dislocation/ Fusion
Dislocation/ Fusion
APPENDK 4: Pain Assessrnent Form
Date: Nam: HSCU:
PAIN ASSESSMENT VISUAL ANALOGUE SCALE (VAS)
1. Do you have pain ot rcst ? Ycs - No I f so, indicatc pain ai nst (wiihin the 1st 24 houn):
No pain
Worst pain possible
I
Wherc is your p in? How long docs it l u t for?
2. Do you have pain wiih activitv ? Ycs - No - Ifso, indicatc pain wiih acdvity:
No pain
Worst pain possible
Wherc is your pain? How long does it last for'?