The Effectiveness of footwear, orthoses

and casted devices in redistributing plantar pressure: a systematic review of

the literature

Sharon Andrews

A dissertation submitted in partial requirement for the Bachelor of Science Degree (with Honours)

In podiatry 2004

Division of Podiatry Centre for Healthcare studies Faculty of Applied Sciences

University College, Northampton Word count: 11 618

Structured Abstract

Background

The need for the study

Podiatrists see patients with systemic and painful foot conditions and

provide preventative care and palliative relief. A range of materials, shoe

inserts, off-loading devices, therapeutic footwear and footwear adaptations

are available. To make the most effective choice appropriate measures of

effectiveness are required. Reducing plantar pressures is often the

objective. This review will consider pressure studies in two areas relevant

to podiatric practice: diabetes and painful foot conditions.

Diabetes

It is estimated that 2% of the UK population have Type I diabetes

(Hutchinson 2000). Studies from Australia, Finland, the UK and the USA

report the incidence of ulceration among people with diabetes as 2.5 –

10.7% and amputation rates as 1.8 -2.23%(Hunt and Gerstein 2003).

Footwear, orthoses and casts are important in the prevention and

treatment of diabetic foot problems.

The painful foot

10% of people may experience plantar heel pain (Crawford and Thomson

2004). Postema et al (1998) states that 83% of 459 subjects over the age

of 60 years of age had foot pain. A study of foot-shoe problems in the

2

Netherlands found that 60% of women and 30% of men suffered from

forefoot problems. Rheumatoid arthritis (RA)has a prevalence of 0.5-

1.5% in industrialized nations and in the UK of 36/100 000 in women and

14/100 000 in men (Suarez-Almazor and Foster 2001). Chalmers et al

(1999) reported that 90% of RA patients have foot problems.

Holmes and Timmerman (1990) refer to the 1989 AOFAS President’s

Symposium on The use and abuse of orthotics (sic)(no reference given)

which “concluded that the medical community lacked the objective data to

support the rational use of most orthotics (sic) prescribed to

patients”(p.144)

Objective

To assess research evidence that footwear, orthoses and casted devices

redistribute plantar pressures in the foot in a predictable fashion to allow

informed clinical prescription for foot pressure related problems

Search strategy

Searches of 24 databases, hand-searching of journals, interest groups,

manufacturers and following-up citations

Selection criteria

Types of study included: randomised controlled trials (RCTs) investigating

the quantitative effects of footwear, orthoses and casts in redistributing

plantar pressures at the foot-shoe interface during gait, in adults with

specific health problems. Qualitative measures will be included in studies

where the main focus is pressure measurement.

3

Data collection and analysis

Titles and abstracts were assessed for relevance against objectives,

inclusion and exclusion criteria. Full articles were checked again. Data

was extracted on the following:

1. how subjects were selected for inclusion/exclusion

2. the organisational setting(s) in which the trial took place

3. baseline sample population variables

4. description of the intervention(s) and numbers assigned to each

group

5. period/intervals of follow-up

6. methods/techniques of measurement

7. outcomes

8. findings/conclusions (based on Spencer 2000)

Parallel trials were assessed against quality standards for reporting

parallel randomised control trials (Moher 2001). Most of the included

studies were cross-over trials and were assessed against standards for

critical appraisal of quantitative studies (Griffiths, 2004)

Main Results

Seven RCT’s of mixed quality were identified. The included studies

demonstrated clinical, methodological and effects heterogeneity (Deeks et

al 2001). Pooling of results was, therefore, not possible and a qualitative

synthesis was undertaken.

4

Five studies considered the effectiveness of insoles/orthoses (one good,

two moderate, two poor). All concluded that insoles/orthoses were

effective at redistributing pressure, reducing pressure time integrals and

increasing contact areas. This was found in a variety of populations. The

case for custom-moulding over “off-the-shelf” shoe inserts was not

conclusive. Simple insoles had significant impact on pressure variables.

Moulded insoles were positively perceived by users compared with flat

inserts.

The evidence for footwear is too limited to draw conclusions. The quality

of the two studies was poor.

The DH pressure relief walker performed well in two studies compared

with total contact casts (TCC’s) but the areas examined differed ( forefoot

ulceration or heel pressure). The methodological quality of both papers

was poor.

A single study on the effect of a rocker bar on 42 individuals with primary

metatarsalgia found a reduction in force impulse and peak plantar

pressure over the metatarsals. The addition of insoles (ready-made and

custom-made) produced further off-loading. The quality of the study was

moderate but too limited to be conclusive.

5

Reviewer’s conclusions

Implications for practice

• There is evidence from a single centre RCT that simple cleron

insoles are an effective intervention for pressure reduction in low

risk diabetic patients and moulded inserts are appropriate for higher

risk patients without foot deformity. The insoles deteriorated

significantly over 6 months and should be replaced regularly.

• There is limited evidence from a small unique trial that rocker soles

reduce plantar pressure over the central metatarsals in women with

primary metatarsalgia.

• There is very limited evidence that visco-elastic heel pads reduce

heel pressure in a small unique trial of patients with treated heel

pain.

Implications for research

• Further multi-centre large scale RCTs are required to evaluate the

effectiveness and cost-effectiveness of therapeutic footwear,

orthoses and casted devices for the prevention and treatment of the

insensate and painful foot.

• the development of standard measures and research protocols is

urgently required to improve comparison of outcomes.

• Further research is needed to identify significant pressure variables

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Acknowledgements

I would like to thank the following people for their assistance:

Mike Curran, Senior Lecturer ,Podiatry, UCN Dissertation supervisor, for

on-going help, enthusiasm and direction

Prof.Jackie Campbell, UCN , for her invaluable help with the statistics

Sue Griffiths, UCN for insight into the review process and help with the

quality assessment process

Alan Roslin and the library staff at the Park Campus Library, UCN for

excellent service and assistance in accessing the literature

Sarah Sutton Clinical librarian, University Hospitals Leicester for guidance

on the clinical application of EBM and getting started with on-line medical

literature searching

Sue Barnett, Foot pressure Interest Group (FIG) for the International

Protocol guidelines for Plantar Pressure Measurement

Ann Walsh, Ewan Kinnear and Rheema Draper for kindly proof-reading

and commenting on the text

Most of all, thank you to my husband, John, for coping with the last three

years with humour and equanimity.

Thanks also to Esther and Tom for successfully being very nice people

and my children at the same time

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ABBREVIATIONS

AFO Ankle foot orthoses

ANOVA Analysis of variance

BMI Body Mass Index (weight in kilo/height in metres2)

DM Diabetes mellitus

FO Foot orthoses

FTI Force time integral

kPa kilopascal = 1000 pascals = 1 Newton per sq metre

MTPJ Metatarsal-phalangeal joint

N Newton

PCT Primary care trust

PPP Peak plantar pressure

PTI Pressure time integral

PWB Prefabricated walking boot

RA Rheumatoid arthritis

RCT Randomized controlled trial

RCW Removable cast walker

s seconds

RCB Removable cast walker

RRB Rigid rocker bottom

TCC Total contact cast

VAS Visual Analogue Scale

VPT Vibration perception threshold

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Table of Contents

Page

Abstract 1 Acknowledgements 7 Abbreviations 8 Background 10

Review of the literature 12

Search strategy 35

Inclusion and exclusion criteria 36

Methodology 41

Data extraction 42

Characteristics of included studies 43

Ranking of studies 54

Results 61

Discussion 66

Reviewer’s conclusions 69

References 71

Bibliography 79

Appendices 92

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Background

Mechanical therapy and footwear advice are central to the podiatrist’s

workload. For successful treatment, it is important to make the most

effective choice from the options available and to know what measures

are appropriate to assess effectiveness. Off-loading is the aim of

mechanical therapy in diabetes and for painful foot conditions.

Diabetes

It is estimated that 2% of the UK population have Type I diabetes

(Hutchinson 2000). Studies from Australia, Finland, the UK and the USA

report the incidence of ulceration among diabetics as 2.5 – 10.7% and

amputation rates as 1.8 -2.23%(Hunt and Gerstein 2003). Lavery et al

(2003), in a two year study of 1666 individuals with diabetes, found that

15.8% presented with or developed an ulcer.

Clinical guidelines (NICE 2004) on the prevention and management of foot

problems in Type 2 diabetes made five research recommendations, three

of which are relevant to this study:

4.1 therapeutic footwear should be evaluated for effectiveness and

cost effectiveness in patients at higher risk of ulceration

4.3 further research is required to identify the appropriate level and

combination of risk factors at which patients should be categorised

as at high risk for ulceration

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4.5 the use of standardised measures … in research studies would

greatly enhance the ability of reviewers to undertake better

analysis, including comparison of outcomes of interventions (NICE,

2004 p.12)

Foot ulceration is preceded by peripheral vascular disease, neuropathy

and repetitive trauma (Kastenbauer et al 1998). Loss of protective pain

perception and proprioception produces abnormal foot loading, followed

by tissue damage and ulceration (Spencer 2003

Footwear adaptations and pressure-relieving devices are recommended

throughout the National Guideline for diabetic foot care (Hutchinson 2000,

NICE 2004) and the National Service Framework for diabetes

(Department of Health 2002. Research has suggested a threshold

pressure level predictive of ulceration. This review considers the evidence

that interventions off-load vulnerable areas.

The painful foot

Mechanical therapy is used to redistribute pressure away from painful

joints, to stabilise, to provide shock absorption or to accommodate foot

abnormalities (Pratt and Tollafield 1995). Corrective insoles are provided

which appear to correct foot position and improve patient comfort. Mueller

(1997) states that high pressures from orthoses, prosthetics or footwear

cause pain. Indirect measures are frequently used to assess whether

pressure redistribution is occurring (e.g. visual analogue (VAS) pain

11

scores or patient compliance). This approach relies on assumptions about

pathogenesis and treatment which may be incorrect. This review

considers the quantitative research available to support the underlying

principle that orthoses “work “ by redistributing dynamic pressure

An overview of research is offered below.

Review of the literature

Systematic Reviews

A systematic review of off-loading devices for diabetic foot problems found

limited evidence that orthoses were more effective than callus removal in

preventing ulcers. Limited evidence existed regarding the effectiveness of

two types of orthotic devices. The evidence for therapeutic shoes was

very limited. There was very limited evidence for TCCs as effective

treatments for diabetic foot ulcers. Quantitative measures used for

assessment were indirect i.e. actual plantar pressure is not measured.

Outcome measures included re-ulceration rates, healing rates and healing

times (Spencer 2000).

TTCs, pneumatic and removable cast walkers (RCWs) were

recommended to off-load ulcers in a cost-effectiveness review (Sinacore

1996). Reviewers critiquing this study noted that the choice of

comparators was not justified, the definitions of a healed ulcer varied

between studies and the included studies were equally weighted despite

differences in quality (NHS CRD 1998).

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A systematic review of interventions for treating plantar heel pain included

heel pads and orthoses. Outcome measures tended to be VAS pain

scales. Due to the small scale of the included studies and poor

methodological quality, there was little evidence to support treatment over

no treatment in any intervention. (Crawford and Thomson 2003)

No current systematic review of the literature considers the effect of

footwear and orthoses on dynamic in-shoe plantar pressures.

Literature reviews

Landorf and Keenan(1998) evaluated foot orthoses (FO’s) by outcomes

such as patient satisfaction, pain and deformity, and plantar pressure.

They noted that “most reasoning for their (FO’s) use is anecdotal, with a

lack of scientific evidence to support the claims many practitioners make”

(p105). Footwear is not included in their review. Inclusion criteria and

quality assessment is not provided.

A critical review by Pratt (2000) quality assessed published articles about

FOs. Accepted trials treated foot and shoe as “a basic functional unit”

(p399). The search strategy was not described. Only 40 references of low

quality were identified and these were not critiqued.

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Choice of in-shoe pressure measurement devices

A number of systems are available to measure foot function (Landorf and

Keenan 1998). Some measure static rather than dynamic pressures or

measure barefoot forces. Cavanagh and Ulbrecht (1994) provide an

overview of the rationale and methodology of clinical plantar pressure

measurement. Those systems requiring individuals to strike a pressure

sensitive plate present difficulties for people with mobility problems and/or

poor eyesight. Gait may be altered as subjects target the force plate.

(Rose et al, 1992). The value of a single barefoot footfall is questionable

when considering the effect of shoes or FO’s or the influence of shoe wear

on pressure distribution (Alexander et al 1990). Dynamic pressure

distribution demonstrates “at risk” areas for plantar ulceration in diabetic

individuals better than static ones. (Alexander et al 1990)

Pressure readings from floor-mounted transducers cannot be directly

compared with in-shoe transducers because of differences in sampling

speed and sensor resolution.

Pressure is derived from force. Transducers estimate force by “measuring

the deformation caused by an unknown force on a material with known

force/deformation properties” (Cavanagh and Ulbrecht 1994 p.125). The

dynamic forces occurring during walking have three components: vertical,

anterio-posterior shear and medio-lateral shear. No commercially

available in-shoe systems measures shear forces.

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Measurement systems should be assessed for suitability. (Roy 1988,

Rosenbaum and Becker 1997; Barnett 1998) Sampling rate and sensor

resolution are more important in dynamic than in static systems.

Measurement technology should provide data that is accurate,

reproducible and repeatable with a high degree of reliability and durability,

minimum variability and at an affordable cost. Specific technical

problems include hysteresis, creep and linearity. These can be adjusted

for if a consistent pattern can be identified. Environmental factors, such

as temperature and humidity, are a particular problem in the shoe (Finch

1999). The quality of calibration by the manufacturer and carried out in

the research or clinical environment is essential to good quality recording.

(Nicolopoulis et al 2000). Resch et al (1997) describe the problems found

by frail elderly patients, standing on one leg to calibrate a sensor.

Measurement technology

In-shoe systems dominating the literature are matrix systems: F-scan

(Tekscan,Inc. South Boston, MA) and the EMED system (Novel GMBH,

Munich, Germany). No study using F-Scan met inclusion criteria for this

review. One included study used the Parotec system ( Paramed,

Germany ).

Emed

EMED (Novel GMBH, Munich, Germany) is a range of instruments for

recording and evaluating static and dynamic pressure distribution on flat

and curved surfaces. EMED Pedar is an in-shoe pressure analysis tool

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based on capacitance. Finch (1999) describes capacitance technology as

two conducting wires, separated by an insulating layer, which vary in

distance according to pressure. Emed Mikro (or Micro) is a portable

version. Pedarmobile dispenses with the cable linking subject to data

collection computer, removing the need for gait-altering turns.

According to Graf (1993) capacitance measurements allow shear forces to

be compensated for without changing sensor characteristics. Emed Pedar

enables bi-lateral in-shoe pressure analysis, recording static and dynamic

real time measurement. Described by Graf as “highly accurate”, the

flexible 2mm insoles have around 85 sensors with a resolution of one

sensor/cm2. Adult versions come in standard shoe sizes which are not cut

to fit. Sampling frequency is variable. Data is collected in an infinite loop

and the last 1000 pictures stored. This equates to about 17 seconds (s)

walking time. Kernozek, La Mott and Dancisak (1996), Rozema et al

(1996) and Barnett (2002) demonstrated reasonable reliability in bench

and dynamic tests.

Finch (1999) notes that insole systems may affect the coefficient of friction

between the foot and the shoe, but Lavery et al (1997b) states that EMED

insoles do not affect gait. Sampling frequencies can be increased to

100Hz but as frequencies increase the proportion of sensors sampled

decreases to maintain a sampling rate of 990 sensors per second. Thus,

high frequencies result in low resolution. The flexibility of the insoles

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allows good conformity but on curved surfaces vertical forces (which are

converted to pressure readings) become vector forces(non-perpendicular).

EMED has a lower threshold of 20kPa to reduce noise during recording

but loads of less than this magnitude occur during parts of the gait cycle.

In a comparison of Emed Pedar with a Kistler Force plate, pressures were

consistently 3% lower on Emed for this reason. (Barnett 2002)

Kernozek , La Mott and Dancizak (1996) state that the key to

measurement with sensors is the ability to calibrate each sensor. This is

possible with the Pedar and Parotec systems. Calibration is via a

patented air bladder pressure device.

Parotec

Parotec (Paromed, Munich) is an insole system based on 24 conductive

transducers embedded in 2.5 mm PVC. Each transducer is embedded in

a hydrocell with a resolution of 2.5kPa and a range of 600kPa. The

transducer consists of a membrane on a mounting ring, which bends a

silicone beam when deflected by applied pressure. The deflected beam

alters resistance in the transducer producing a measurable deviation in

the current. Each sensor is positioned at a point of peak pressure as

identified from 350 subjects. The insoles are calibrated by the

manufacturer and are reported to have a measurement error of less than

+/- 2.5%. (House et al 2002)

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The sensors cover 46% of the insole surface. The software stores

pressure data at a rate of 250Hz for five complete gait cycles, ignoring the

first steps. (Hsi, Lai, Yang 1999). As with Pedarmobile, there are no

cables connecting the insole to the data-collecting computer. A rapid

sampling rate improves the system’s suitability for measuring pressures

during running. Bauer, Cauraugh and Tillman (1997) found that Parotec

provided stable and consistent values across six postural variables.

Chesnin, Besser and Selby-Silverstein (n.d.) found no discernable drift,

negligible hysteresis, temperature drift, humidity drift or non-linearity over

a range of bench tests. In a study supported by the manufacturer, they

compared output from Parotec with a force system and found correlation

coefficients in the good to excellent range. Different insole sizes are

available with the sensors placed in the correct relative position for each

size.

The system requires an acceptance of pre-determined points of peak

pressure, which may not be appropriate for subjects with deformity or

abnormality. When assessing the effect of FOs, the relative position of the

sensors may also be changed.

Comparing results from different studies

Inter- and intra- sensor variability, differences in calibration, sensor

resolution and sampling speeds make quantitative comparisons between

pressure studies inadvisable and results should be used qualitatively.

Shear stress cannot be measured and this is significant in many

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pathologies. The system chosen should be appropriate to the study design

and population (Dhalla, Johnson and Engsberg 2003, Hartsell, Fellner and

Saltzmann 2001, Lavery, 1997a).

The Foot Pressure Interest Group (FIG) produced draft protocol guidelines

for plantar pressure measurement (Barnett 1998) to encourage

comparability between studies. Regarding in-shoe systems,

recommendations were made in a variety of areas (See appendix 1). As

the protocol follows recommendations in the wider literature it has been

referred to when assessing methodological quality.

Measurement variables

In-shoe devices measure magnitudinal, temporal and spatial variable in all

or part of the foot (Harrison and Hillard n.d.). Force is mass x acceleration

and is measured in Newtons (N). Pressure is the distribution of force over

an area. The SI unit is kilo Pascals (kPa) but Nm-2 is frequently used in

the literature. (Rosenbaum and Becker 1997) Applied force is composed

of vertical force (the effect of gravity or ground reaction force) and shear

forces (friction). Vertical forces are usually the larger component. Forces

are individual but consistent if measured on consecutive days or after

several months. Time parameters are more consistent than force

parameters (Roy 1988).

More research is required to identify the most useful variable in research

or clinical practice.(Hodge et al 1997, Lavery et al 2003, Pitei et al 2000,

19

Barnett 1998). Definitions/formulae are not consistent (Harrison and

Hillard n.d.). Mean peak plantar pressure (PPP) is the maximum pressure

detected by each sensor during the stance phase of gait and is described

in kPa or N/cm2 (Stess, Jensen and Mirmiran 1997).

Pressure-time integral (PTI) is peak pressure multiplied by duration of

weight-bearing in seconds. (Stess, Jensen and Mirmiran 1997). This

variable includes loading time and is a better indicator of the pressure

sustained during each gait cycle.

Walking speed data is important in trials where subjects self-select a

comfortable pace. Zhu, H. et al (1995) demonstrated that gait speed has

significant effects on plantar pressures. A self-selected pace better

reflects normal walking style (Barnett 1998) but walking speed data

should be collected and measurements rejected when velocity deviates by

more than 10% from the average.

Pressure variables and the diabetic foot

PPP became significant when linked with ulceration in the diabetic foot

(Boulton et al 1983, Boulton et al 1985, Veves et al 1992, Lavery et al

1998). The possibility of a threshold for ulceration was investigated

(Stess, Jensen and Mirmiran 1997, Frykberg et al 1998, Mueller 1999,

Lavery et al 2003) but it is now recognized that ulceration is the result of

the interplay between pressure, time and contact area and the permissive

effects of neuropathy (Masson et al 1989). A case control study of 225

20

age-matched patients evaluated risk factors for ulceration (Lavery et al

1998). PPP>65N/cm2, history of amputation, foot deformities and

neuropathy were significantly associated with ulceration. Stacpoole-Shea,

Shea and Lavery (1999) in a study of 36 subjects found a combination of

PPP and PTI were predictive of ulceration. Sensitivity was 83% and

specificity was 69%. A prospective study over 3.5 years of 187 type 2

diabetic patients with a history of ulceration analysed risk factors (

Kastenbauer et al 2001). Elevated vibration perception threshold (VPT),

increased PPP and daily alcohol intake were significant predictors.

Raised VPT was the strongest predictor (relative risk = 25.4). A 2-year

study of 1 666 diabetic patients evaluated dynamic PPP as a screen for

ulceration (Lavery et al 2003). PPP alone was insufficient as a diagnostic

tool for high-risk. Strong correlations were found between elevated

pressure and foot deformity and with callus. Stess, Jensen and Mirmiran

(1997) measured PPP, PTI and force-time integral (FTI) over three areas

of the forefoot in 97 diabetic patients. All pressure variables were raised

but individual variables were not discussed. Barnett (2002) found that PTI

was most influenced by diabetes and could be the most important variable

to alter with footwear and orthotic interventions.

Research has identified strong links between plantar callus, raised PPP

and ulceration. Wrobel et al (2003) in a cross-sectional study of 152 men

with diabetes found that callus increased PPP by up to 29%. In a small

group study, callus removal was found to reduce PPP by 25-32% (Pitei,

21

Foster and Edmonds 1999). Callus should be removed before assessing

the affect of interventions on PPP (Barnett 1998)

Pressure variables and the painful foot

Metatarsalgia in rheumatoid arthritis is presumed to be due to excessive

pressure to the metatarsal heads (Hodge, Bach and Carter 1999). In a

study of 12 people with RA and a history of forefoot pain, PPP were

assessed and patients asked to complete a VAS pain score whilst wearing

prefabricated or custom-made EVA insoles (with/without metatarsal

dome). Standing and walking pain were highly correlated suggesting that

repetitive pressures were less significant than in the insensate foot.

Pressure was distributed more uniformly with orthoses and both types

significantly reduced average pressure. Custom-moulding with dome

significantly reduced walking and standing pain and was preferred by most

subjects. Pain and peak pressure were not correlated but pain and

average pressure were. This correlation accounted for only 32% of the

variance. It should be noted that the authors pooled the results from 20

out of 24 feet and the sample size was small. Postema et al (1998)

similarly found no correlation between pain scores and peak pressures in

a study of 42 patients with primary metatarsalgia.

Types of intervention

Total Contact Cast (TCC)

A TCC is a close-fitting, below knee cast which protects neuropathic lower

limbs and promotes healing of ulcers whilst allowing the patient to remain

22

mobile. (Sinacore1996). TCC’s had a 91% healing rate and led to

substantial improvements in healing times compared with in-hospital care

and daily wound dressing. Casting requires highly skilled people to make,

renew and replace on a regular basis. Complications include superficial

abrasions (27%) and fungal infections (15%). With undiagnosed

osteomyelitis, casting can lead to more serious complications (Sinacore

1996). A Cochrane review of pressure-relieving interventions for diabetic

foot ulcers found a single poor quality RCT testing TCC’s (Spencer 2000).

This does not mean that they are not effective but that more and better

research is required.

Beiser et al (1991) investigated pressure variations in different cast

designs and subjects were asked about comfort and ease of walking.

Short leg casts (with/ without cast shoe) had greatest overall performance.

Short leg casts with walking heel were most efficient at reducing peak

pressures but awkward to wear. Pressures decreased as immobilization

moved up the leg. PPP at the first metatarsophalangeal joint (MTPJ) in 20

asymptotic subjects was compared in athletic shoes (baseline condition),

two types of post-operative shoes (one with a 1st MTPJ cut-out) and a

fibre-glass short-leg walking cast. The cast and shoe with cut-out

significantly reduced pressure (Corbett et al 1993). Zhu et al (1995)

postulated that TCC’s decelerate gait. TCC’s have little padding,

reducing compression, preventing shear within the cast.

23

Rubber bottom cast boots, conventional short leg casts and TCC’s were

assessed for PPP in 10 healthy volunteers (Conti et al 1996). A significant

reduction in forefoot pressure was found in both types of cast. Average

weight-bearing area was significantly increased in the TCC, reducing

forefoot pressures. Normal gait patterns are bi-phasic with pressure

peaks at heel strike and toe-off. With casts, the force curves were bell-

shaped due to a flat-footed gait and restricted ankle movement. Subjects

were not tested in normal footwear. In normal subjects, casts reduce

forefoot and rearfoot loading, redistributing them to the mid-foot.

Total contact casts with terminal devices

Cast boots and heels were added to TCCs and compared with therapeutic

shoes (Lavery et al 1997a). For hallux and 1st MTPJ ulcers the devices

were equally effective. TCC plus cast heel was more effective for 2nd-5th

MTPJ ulcers. Casts were superior to therapeutic shoes and baseline

footwear. Dhalla, Johnson and Engsbert (2003) added cast shoes and

heels to TCCs. 28 healthy volunteers were assessed with six

interventions: athletic shoe (control), TCC and TCC with four different

terminal devices. For the forefoot, TCC with conventional cast or rigid

rockers were best and would be indicated for fore-foot ulcers. All devices

reduced midfoot pressure by at least 40%. In the rear-foot, PPP was

significantly reduced in all configurations excluding the rigid rocker heel.

This suggests that TCCs can be augmented.

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Removable cast walkers compared with TCCs

1. Asymptotic subjects

The advantages of prefabricated walking boots (PWB) are: time of

application, lightweight construction, relative low cost, provision of

consistent and continuous pressure to off-load and minimize shear forces,

ease of wound monitoring and hygiene (Hartsell, Fellner and Saltzman

2001). It was hypothesized that TCC and PWB would significantly and

similarly reduce PPP compared with running shoes. 9 healthy volunteers

were assessed. A 3/8” open-cell urethane foam insole was added to the

PWB. Compared with running shoes, TCC’s and the modified PWB

significantly reduced pressure across the forefoot with an insignificant

increase at the mid-foot. The impact of shear stresses, patient

compliance, differences between healthy and symptomatic patients and

activity levels were not addressed.

Aircast pneumatic walkers were equally good or better at reducing PPP

than TCC’s in a small sample of 12 healthy volunteers(Baumhauer 1997).

In 18 healthy subjects, the Bledsoe Diabetic Conformer Boot was found to

reduce PPP as well as a fibre-glass TCC( Pollo et al 2003)

2. In diabetes

In a study of 25 diabetic neuropathic subjects, the effectiveness of TCC’s,

therapeutic shoes and removable walking casts (DH pressure relief

walker, Aircast pneumatic walkers, Three D dura-steppers and CAM

walkers were compared. The DH pressure relief walker which did not

25

vary significantly from the TCC in reducing PPP over forefoot ulcers.

Lavery et al (1996)

Boulton and Armstrong (2004) suggest that the failure of RCWs in clinical

practice is because patients remove them. “Instant” TCC’s made from a

RCW made unremovable with the application of plaster or cohesive

bandage are proposed as a solution.

Footwear

1.In diabetes

Perry et al (1995) compared plantar pressures in 39 subjects barefoot,

wearing leather-soled oxford-style shoes and in inexpensive running

shoes. (Diabetes and neuropathy n= 13, diabeties without neuropathy n=

13, healthy controls, n=13). The oxford style shoes did not reduce

pressures from barefoot levels. Running shoes reduced pressure

significantly at the heel and forefoot. It was concluded that individuals with

insensate feet should not wear leather-soled shoes and the running shoes

are a useful alternative for individuals with sensory loss and without foot

deformity.

Pitei et al (1996) (abstract only available) measured in-shoe pressures for

22 diabetic patients in three types of footwear – patients’ own shoes,

surgical shoes with an EVA-moulded insole and standard trainers. When

newly fitted, the insoles significantly reduced plantar pressures compared

26

with patients’ own shoes. When worn in (duration not given) pressures

were further reduced. Trainers were less effective at pressure reduction.

Plantar pressures were assessed in 49 diabetic neuropathic patients (no

existing or previous ulceration, n=19; existing or previous ulcers, n=30)

(Resch et al 1997). PPP and PTI were assessed in patients’ own

comfortable walking shoes, own shoe with Frelens custom-moulded semi-

rigid insoles, jogging shoe with and without insoles and an orthopaedic

shoe with metatarsal bar and insole. The high degree of variability of the

F-Scan device (25-30% accuracy) made it impossible to draw any

conclusions. The orthopaedic shoes tended to increase pressures and

were found uncomfortable and awkward by patients. This study did not

claim significant improvements from the interventions, possibly because

the baseline was a good quality walking shoe.

Kastenbauer et al (1998) compared specially designed running shoes with

a custom-made insole in an “in-depth” shoe. Running shoes were as

effective in reducing pressures at the central metatarsals in a sample of 13

diabetic patients

2. Diabetes and amputation

30 patients with diabetes and trans-metatarsal amputations had PPP

measured at the distal residuum and the contra-lateral forefoot in six types

of footwear; full-length shoe with toe-filler (baseline) and combinations of

27

total contact insert, ankle foot orthoses (AFO), rigid rocker bottom sole

(RRB) or short shoe. All conditions except the short shoe reduced PPP

on the residuum. The full shoe with insert and RRB had few complaints

from patients. The addition of an AFO reduced pressure but patients had

functional problems. (Mueller, Strube and Allen1997)

Insoles/Orthoses

1.Asymptotic subjects

Windle, Gregory and Dixon (1999) used Parotec to assess the shock

attenuation characteristics of visco-elastic, polymetric foam, Saran

(military issue) and Sorbothane insoles in military boots during running

and marching compared to a “no insole” baseline. 11 military recruits

were trialled. All insoles significantly reduced PPP at heel strike and

forefoot loading. The Sorbothane insole was significantly more effective

than the other insoles. House et al (2002) demonstrated that 100 – 130

km of running on visco-elastic or polyurethane insoles did not reduce

shock absorption. Foam insoles were more effective than visco-elastic

and did not degrade. The most effective version reduced heel PPP by

37% and forefoot PPP by 24%.

Novick et al (1993) studied the effect of three types of rigid orthoses on

PPP in 10 subjects to identify whether FO’s were effective for off-loading

sites of ulceration in diabetic individuals. Interventions were 1/8” Spenco,

two rigid Sorbotholen custom-made insoles, one with 3/8” relief under the

1st MTPJ, the other without. Least pressure at the 1st MTPJ was recorded

28

with the relief orthoses, the greatest with the plain rigid version, followed

by simple Spenco insoles. Mid-foot and heel pressures were minimised

with the Spenco insole, but increased with both rigid orthoses.

Brown, Rudicel and Esquenazi (1996) tested PPP in 10 subjects wearing

off-the-shelf and customized orthoses in standard extra depth shoes.

Plastizote, cork and plastic insoles reduced pressures at the forefoot, heel

and 2nd-5th MTPJ, but increased pressures at the mid-foot.

2.In diabetes

A small-scale study investigated the impact of flat and moulded

customized inserts on PPP under the MTPJ’s of 12 diabetic patients,

some with neuropathy. (Lord and Hosein (994) Testing the hypothesis that

moulded inserts would be more effective than flat, the authors suggested

that this occurred by redistributing load to the midfoot and by cushioning.

Results were treated with caution because of problems with the pressure

measurement system (F-Scan). Ashry et al (1997) considered the

effectiveness of three different insoles in reducing plantar pressure in a

sample of 11 diabetics with amputation of the hallux. A base-line reading

in standard extra-depth shoes was compared with the same shoes with

customized 6 mm plastizote insoles with and without the addition of a

metatarsal pad, arch pad or both on the amputated and non-amputated

foot. Mean peak pressure was significantly reduced across the forefoot,

lesser toes and heel in both groups but there was no significant difference

between interventions.

29

Lobmann et al (2001) compared the effects of a mixed materials moulded

orthosis (14 mm thick) on plantar pressure in 81 type 2 diabetics with no

history of ulceration. 18 subjects were considered at risk of ulceration

because of high plantar pressures and these received insoles. 63

subjects acted as the control group and wore conventional footwear.

Using pedobarograph, a reduction of 30% was found in maximum peak

pressure of the whole foot in the “at risk” group. Pressures gradually

increased during the following 12 months sush that a 13% improvement

over baseline measures remained after one year. The control group

increased pressures over the year and there was no significant difference

between the two groups at the end of the study. This demonstrates the

importance of considering insole degradation.

Frykeberg et al (2002) considered the effect of a rocker insole on forefoot

pressures on 25 subjects (with and without diabetes) wearing their own

footwear, standard post-surgical boots and the boot with a rocker insole.

The insole produced a reduction in PPP of greater than 40% over the

baseline or the surgical boot alone.

3. The painful foot

McLauchlan et al (1994) used a discrete sensor system (GaitScan) to

compare treatments for metatarsalgia: a felt U-shaped pad and metatarsal

dome. 30 asymptotic patients were investigated. The dome produced a

significant reduction in pressure over 1st – 4th MTPJs compared with

30

baseline values. Poon and Love (1997) study of a metatarsal dome on

plantar pressures and pain in 14 patients with metatarsalgia found that

mean pressure was reduced by 13% at the forefoot. The VAS revealed a

71% reduction in pain scores and 11 subjects found some or marked

improvement of symptoms.

Kelly and Winson’s (1998) assessment of commercially available insoles

compared Viscoped with Langer in 33 patients with primary lesser

metatarsalgia. Langer performed better objectively and subjectively.

Hodge, Bach and Carter (1999) completed a repeated measures pressure

assessment of a variety of orthoses in a group of 12 subjects with

rheumatoid arthritis with foot involvement and pain at the 2nd MTPJ. A

“shoe only” baseline, pre-fabricated and custom-made orthoses of similar

materials, density and size were assessed. The custom-made orthoses

were also tested with the addition of pre-formed metatarsal bars and

domes. Qualitative assessment was made by asking subjects to complete

a VAS Pain Scale, and express a preference for one of the interventions.

All orthoses significantly reduced pressure under the 1st and 2nd MTPJ but

the custom-moulded orthoses with metatarsal dome was the intervention

of choice. A correlation was found between average pressure and pain

but this only accounted for 32% of the variation leading the authors to

conclude that other factors were implicated in pain than PPP. Li et al

(2000) investigated the effect of orthoses on PPP in subjects with

rheumatoid arthritis (n=12) and an age-matched group of healthy subjects

31

(n=8). Moulded polyethylene orthoses reduced PPP and peak force

significantly for both groups, with greater pressure relief and redistribution

in RA patients.

External devices

Schaff and Cavanagh (1990) hypothesized that rocker-bottom shoes

might redistribute PPP in insensate feet. Healthy volunteers were tested

(all US men size 9, n=8)) wearing extra-depth shoes (control) with/without

rocker sole attached. PPP was reduced over the medial and middle MTPJ

(-30%) but increased at the heel, mid-foot and lateral forefoot (+20%).

Force impulse was significantly reduced at the metatarsals (53% medial,

35% control). It is difficult to generalize results as there is such diversity in

rocker bottom shoe modifications (Brown et al 2004) and diabetic patients

may respond differently.

Fuller, Schroeder and Edwards (2001) added rigid rocker bottoms to post-

operative shoes to assess the effect on pressures over the forefoot in 16

healthy females. PPP and FTI were significantly reduced compared with

the post-operative shoe alone.

Three types of rocker soles (toe-only, negative heel and double) were

studied for their effect on PPP in 40 healthy subjects (Brown et al 2004).

PPP, PTI and sensor contact time were compared with a baseline shoe. A

significant reduction was found at the forefoot in all versions. Pressure

was shifted to the mid-foot with the negative heel and toe-only rockers.

32

Summary of the literature

Plantar pressure studies are typified by small sample sizes and short-term

cross-over studies. Very few studies were randomised and the use of

asymptotic volunteers to test interventions for diabetic conditions is

common. Recruitment information is rarely given and ethical and informed

consent only occasionally reported. The general opinion of the research is

that footwear interventions and casts do reduce plantar pressure.

Study design and Statistical Considerations

Cross-over studies

Pressure measurement studies frequently use cross-over studies. This

refers to trials where each subject acts as their own physiological control

by being tested in all interventions. Sample size can be reduced, but

there are potential carry-over effects i.e. one intervention affects the

results of the next intervention. Williams designs account for carry-over

effects but these were not mentioned in trials reviewed above or in

included trials. (Qu, 2003)

Repeated measures

Repeated measures refer to the number of trial runs each subject has with

each intervention and the number of steps nested to find mean values.

Repeated measures reduce intra-patient variability and increase statistical

power. The degree of improvement is marginal and decreasing, therefore

the aim is to find the number of repeats which maximise power but

minimise data over-load. Increasing the number of follow-ups and/or

33

baseline measures from one to three or four, can reduce sample size by

35-70%, but there is little value in more the six or seven measures

(Kernozek, LaMott and Dancisak, 1996; Vickers 2003).

Sample size and data analysis choices

Sample size calculations were rarely offered in the literature. To calculate

sample size, the researcher needs to know (i) the effect size, (ii)

population standard deviation for continuous data (iii) desired power of the

experiment (β) (iv) significance level (α) . The last two are fixed by

convention (usually α = 0.05 and β = 0.8) but the former are unique to the

experiment. Effect size is determined by the investigator. The population

standard deviation is estimated by a pilot study. There was little evidence

of this kind of calculation. For parametric studies, a minimum sample size

of 30 is usually accepted (Pett, 1997)

An underlying normal variation is often assumed and statistical tests

chosen accordingly – particularly analysis of variance. Many are

underpowered and non-parametric tests would be more appropriate (Pett,

1997).

One subject, two feet

A further consideration is raised by Menz (2004) and relates to the use of

data from an individual subject or as two individual feet. Statistical

sampling has an underlying assumption that each observation is

independent (Pett 1997, Polgar and Thomas 2000). This does not apply

34

to a pair of feet. Including both feet doubles the sample size, which might

appear to make the evidence more powerful. The outcome of statistical

analysis is distorted, however, because the observations are not

independent. Menz (2003) recommends that the unit of analysis should

be people, not feet.

Search strategy

The following databases were searched:

1.Cochrane Library including databases of systematic reviews, abstracts

of effects (DARE), central register of controlled trials (CENTRAL),

methodology, health technology and NHS economic evaluation.

2. Clinical effectiveness databases: NICE (National Institute for Clinical

Effectiveness) technology appraisals and clinical guidelines, Research

findings register

3. General health sites: British Nursing Index, AMED, Medline, Embase,

Recal, CINAHL,PRODIGY

4. General databases: British Humanities Index, PsychInfo

5. Full-text electronic journals: Bandolier, BIOMED central, Clinical

Effectiveness, Infotrac, Emerald Fulltext, Highwire, ASSIAnet, Science

Direct, Swetswise, Web of Knowledge

6. ZETOC for tables of contents and conference proceedings

7. Index to theses

8. COPAC

9. Relevant journals were hand-searched.

10.Citations were followed up from relevant articles.

35

Inclusion and Exclusion criteria

Inclusion criteria

Study design

• Randomized control trials

Justification: Systematic reviews of non-RCT’s can compound the

problems of individually misleading trials and produce a lower quality of

evidence. Sackett et al (2000) advises avoiding systematic reviews which

include both levels of evidence unless these are analysed separately.

Types of participants

• Studies of patients with specific conditions where clear

inclusion criteria stated

• Adults

Justification: considering literature on effectiveness of interventions in a

broad spectrum as appropriate to podiatric clinical practice. Eligibility

criteria are necessary to establish where findings can be applied.

Findings with healthy individuals may not be transferable to the target

group. (Barnett 2002)

Outcome measures

• Quantitative plantar pressure measures

36

• Dynamic in-shoe measures.

• An appropriate base-line for comparison as required by study

design

• Adequate sample size

Justification: to test the hypotheses that footwear and orthoses are

effective because they redistribute pressure in real-life situations i.e.

dynamic, in-shoe. Cross-over studies require a smaller sample size than

parallel trials. Of the crossover trials only Hsi, Lai and Yang (1999) offered

a calculation of 22 subjects. For this reason, a minimum sample size of

20 was accepted for inclusion. The only parallel trial (Barnett, 2002) used

a power calculation and found a minimum sample of 47 was required for

the control and intervention groups. Type 1errors are more likely with

small samples. (Pett 1997)

Interventions

• Footwear

o Orthopaedic shoes

o Footwear adaptations for purposes of pressure

redistribution

o Specific types of shoe e.g. running shoes

• Orthoses

o Rigid

o Flexible

37

o Customized

o “Off-the-shelf”

• total contact casts

• surgical shoes/post-operative shoes

• walkers

• ankle-foot orthoses

Justification: these represent the range of interventions for redistributing

pressure regularly available in clinical practice. Combinations of

interventions were also accepted

Measuring devices

• systems which measure in-shoe dynamic plantar pressures

• systems which had been independently tested and

demonstrated to be reliable, accurate, repeatable.

• Thin, flexible, individually calibrated pressure sensors where

used

• systems based on array/matrices rather than a few discrete

sensors

Justification: Most individuals are ambulatory and wear footwear.

Systems should measure actual pressures between the foot and the

shoe/cast. Discrete systems have been shown to alter gait and identified

points of pressure may alter when orthoses/footwear are changed for

38

testing. The thickness of the transducers can cause alterations in gait.

Some insole measurement systems are thick and change the position and

movement of the foot. They can fill the shoe, leaving too little space for

the foot. Thick insoles do not mould to the foot or the orthoses being

assessed. Thin, flexible pressure sensitive insoles overcome many of

these problems. (Nicolopoulis 2002).

Exclusion criteria

Types of participants

• Healthy, asymptotic subjects

• Children

• Non-ambulatory

• Those using walking aids such as walking sticks or frames

Justification: walking aids alter pressures on the foot, change gait and

make dynamic testing difficult (Resch et al 1997). Subjects with systemic

conditions such as diabetes or with biomechanical abnormalities do not

have the same plantar pressure distributions and responses as asymptotic

subjects (Barnett 2002). Children have different plantar pressure

distributions from adults (Rosenbaum and Becker 1997)

Interventions

• Dressings

• Hosiery

39

• Strapping

Justification: These are included if one of a range of interventions. As

temporary interventions, it was decided to exclude them from the study.

Outcome measures

• Qualitative studies unless findings linked within studies with

a primarily quantitative focus e.g. pain questionnaire,

expressing a preference between interventions

• Pressures other than plantar pressures.

• Studies of other gait parameters e.g. timing, sequences,

stance pressure distributions, postural sway

• Studies which focus on barefoot or stance pressure

distributions

• centre of pressure, centre of force studies

Justification: this study is investigating the case that footwear and

orthoses redistribute pressure. Qualitative studies look at indirect

measures. Variables implicated in ulceration, pain and healing relate to

amount and length of pressure and contact area over which it is

distributed. Other variables are not directly related. Barefoot and stance

measures are excluded for reasons explained above. Centre of pressure

and force do not have consistent formulae for calculation and there is

some question of their value in clinical practice. (McPoil and Cornwall

1998; Barnett1998)

40

Measuring devices

• systems which measure barefoot pressures only

• static pressure measurement systems

• discrete sensor systems

• systems for which independent test data could not be found

• early prototypes which were demonstrably unreliable

Language/Date

• English language only

• Post-1990

Justification: The researcher did not have access to translation services

and is aware that this may introduce bias into the selection of data (Khan

and Kleijnen 2001.The technology required was developed from the early

1990’s onwards.

Methodology

Searching was undertaken between August 2003 – April 2004. The

search strategycwas constructed around the inclusion critieria. By

referring to indexed terms a large number of possible search terms were

collated and used to test the available literature (See Appendix 2). A

highly specific search strategy could not be devised. Searches were

sensitive, producing many references. For this reason a list of excluded

41

articles has not been provided although recommended by the Centre for

Disseminations and Reviews. (Glanville, 2001)

Titles and abstracts were assessed for relevance against the objectives of

the review, inclusion and exclusion criteria. Full articles were checked

again. Ideally, this process would be carried out by more than one

reviewer and conducted “blind” – i.e. unaware of authors’ identities. (Khan

and Kleijnen 2001) Because of the nature of this research, this has not

been possible and selection bias may be introduced as a result.

Data extraction

Data extraction is potentially subjective and open to bias. It would ideally

be completed with the reviewer “blinded”, that is, unaware of authorship.

A panel of reviewers to independently assess studies is an alternative

solution. Both options are unavailable in a single-authored dissertation. A

number of extraction protocols are available (Khan and Kleijnen 2001) but

relate to double blind parallel RCTs. In this study data was extracted on:

• how subjects were selected for inclusion/exclusion

• the organisational setting(s) in which the trial took place

• baseline population variables such as age and gender

• description of the intervention(s) and numbers assigned to

each group

• period and intervals of follow-up

• methods and techniques of measurement

• Outcomes

42

• findings and conclusions (based on Spencer 2000)

Characteristics of included studies

Study Armstrong (1999)

Methods Repeat measures, crossover design single centre RCT

Method of randomisation of treatments not described

Participants 25 consecutive diabetic patients with grade 1A (University of

Texas)((Oyibo et al n.d.) plantar forefoot ulcerations: existing

or recently healed single ulcers, peripheral neuropathy and a

diagnosis of DM.

Neuropathy established as loss of protection to 10g

monofiliament and biothesiometer

Interventions

Baseline: Reebok canvas sneaker

Total contact cast: method of Kominsky without plywood sole

Aircast pneumatic walker

DH pressure relief walker

Prescription-depth inlay shoes with PW Minor stock inlays

Outcomes PPP (N/cm2)

PTI (N.s/cm2)

43

Measured over heel

Measurement system

Emed pedar

Five trials, mid-gait steps, 40 steps per subject per modality

Allocation concealment

No

Notes High percentage of male participants (92%) Type I/ type II

not described. Treatment of participants not described. No

a priori sample size calculation. No discussion of informed

consent or ethical approval. Suitability of modalities for

patients with active ulceration not discussed. No review after

trial or follow-up to ensure no adverse effect. Did not appear

to be supported by industry. Masking not described.

Full citation

Armstrong, DG and Stacpoole-Shea, S (1999) Total contact

casts and removable cast walkers: mitigation of plantar heel

pressure Journal of the American Podiatric Medical

Association 89 (1) pp 50-53

Study Barnett (2002)

Method Prospective randomised clinical control trial

Single centre

44

Method of randomisation described

Baseline, three month and six month follow-up

Mixed methods

Participants 103 Type I and Type II diabetic individuals without major

vascular disease, foot deformity, mobility problems, existing

or previous ulceration

Control and intervention group matched demographically

and health characteristics except for age

Interventions

Control: 3 mm unadapted Cleron shoe inserts (n=52)

Intervention: polyurethane gel and EVA orthoses (off-the-

shelf)

(n=51)

Pressures measured in standard extra-depth orthopaedic

shoes. Inserts transferred to patients’ own footwear

between follow-ups

Outcomes PPP (kPa/cm2)

PTI (kPa.s/cm2)

Contact area

Pressure variables measured over 9 described masks and

the whole foot

Bristol Foot Health Questionnaire

45

Diary of wear

Measurement system

Emed pedarmobile

Allocation concealment

No

Notes Participants with DM recruited from City PCT podiatry

database. Intention to treat analysis included. Does not

appear to be supported by industry.

Full citation Barnett, S, (2002) The clinical effectiveness of orthoses

prescribed to control and reduce diabetic foot pathology

Ph.D Thesis, University of the West of England

Study Fleischli (1997)

Method Repeated measures crossover study

Single centre RCT

Method of randomisation of treatments not described

Participants 26 patients with existing or recently healed diabetic

neuropathic plantar forefoot ulcers. Analysed in two groups;

46

Forefoot (metatarsals) ulcers (n=19), Hallux ulcers

(n=7). Groups not matched. VPT assessed with

biothesiometer. Some participants do not meet generally

accepted criteria for neuropathy (VPT > 25)

Baseline demographic and health data given

Interventions

Baseline: rubber soled canvas sneaker

Total contact cast: method of Coleman, without plywood sole

DH pressure relief walker

Darco ortho-wedge shoe (also described as Darco half-

shoe)

Darco rigid-soled post-operative shoe

Accomodative felt and foam dressings

Outcomes PPP (Ncm-2)

Percentage change from baseline

Measured over sites of ulceration

Measurement system

Emed pedar

Allocation concealment

47

No

Notes Recruited from clinics at University health systems of an

American city. No sample size calculation. Ethical issues

not addressed. Masking not explained. No support from

industry reported.

Full citation Fleischli, JG et al (1997Comparison of strategies for

reducing pressure at the site of neuropathic ulcers Journal of

the American Podiatric Medical Association 87 (10) pp.466-

472

Study Hsi (1999)

Method Single centre RCT.

Method of randomisation of treatment order not described

Two-factor analysis of variance with interactions between

orthosis and subject. Repeated measures, cross-over

design

Participants 22 consecutive patients with treated unilateral heel pain

Interventions

Baseline: patients’ own shoes and hosiery

48

Visco-elastic heel orthoses

Outcomes PPP (kPa/cm2)

PTI

Foot to sensor contact time

Measured over whole foot

Measuring system

Parotec

Allocation concealment

No

Notes Did not appear to be supported by industry

Full citation Hsi, WL; Lai, JS and Yang, PY (1999) In-shoe pressure

measurements with a visco-elastic heel orthosis Archives of

physical medicine and rehabilitation 80 (7) pp 805-810

Study Lavery (1997b)

Method Repeated measures crossover study

Single centre RCT

Method of randomisation of treatment order not described

49

Participants 32 consecutive patients with DN and existing or recently

healted plantar forefoot ulcers. Method of establishing DM

or neuropathy not described

Stratified into three sub-groups: 1st MTPJ ulcers (n=10), 2nd

– 5th MTPJ ulcers (n=12), ulcers of hallux (n=12)

Interventions

Baseline: thin rubber-soled canvas oxford sneaker

Extra-depth shoes in men and women’s styles

New Balance cross-trainers in men and women’s styles

SAS Timeout (men) and Free-time (women) comfort shoes

Each assessed with and without plastazote/urethane insoles

Outcomes PPP (N/cm2) and percentage change from baseline over the

three sites of ulceration

Measurement system

Emed pedar

Allocation concealment

Yes

Notes Recruited from clinics at an American city university hospital.

No a priori sample size calculation. Patient characteristics of

50

sub-groups not given. Ethical issues not addressed.

Masking over ulcers not described. Does not appear to be

supported by industry.

Full citation Lavery, LA et al (1997b) Reducing plantar pressure in the

neuropathic foot: a comparison of footwear Diabetes Care

20 (11) pp 1706-1710

Study Postema (1998)

Method Repeated measures, cross-over design

Multi-centre double-blind RCT

Method of randomisation of treatment order described but

not justified

Mixed methods

Participants 42 patients with a history of primary metatarsalgia

41 female

Clear inclusion and exclusion criteria

Interventions

Baseline: same brand of extra depth shoe

51

Standard insole and custom-made insole of the same

materials. Standard insole not a commercial product but

made to standard pattern rather than customized.

Rocker bar

Pain questionnaire and patient preference

Outcomes PPP (N/cm2)

Force impulse (N s)

Pain scores from patients with pain

Preference ratings

Measurement system

Emed pedar

Allocation concealment

Yes

Notes Recruited from three areas of the Netherlands. No a priori

sample size calculation. Does not appear to be supported

by industry

Full citation

Postema, K et al (1998) Primary metatarsalgia: the influence

of a custom moulded insole and a rockerbar on plantar

52

pressure Prosthetics and orthotics international 22 (1) pp.35-

44

Study Redmond (2000)

Method Repeated measures crossover study

RCT – probably single centre

Treatment order randomised but method not described

Participants 22 subjects with excessive pronation (criteria given)

Interventions

Baseline: Dunlop Volley athletic shoe

Non-cast insole made of card with a 60 high density EVA

varus rear-foot post

Modified Root orthosis: 4mm high density polypropylene

shell, PVC cover, 60 extrinsic EVA varus rear-foot post

Outcomes Maximum force (N)

FTI (N.s)

PPP (kPa)

Maximum PPP(kPa/cm2)

PTI (kPa.s/cm2)

Contact area (cm2)

53

Measurement system

Emed pedar

Allocation concealment

No

Notes No subject demographic information. No recruitment

information. Ethical approval form University of Sydney. No

a priori sample size calculation. Non-casted orthosis is not

an appropriate treatment for abnormal pronation. Does not

appear supported by industry.

Full citation Redmond, A; Lumb, PS and Landorf, K. (2000) Effect of cast

and non-cast foot orthoses on plantar pressure and force

during gait Journal of the American Podiatric Medical

Association 90 (9) pp.441-449

Ranking of studies

Seven RCTs met inclusion criteria. Heterogeneity in every aspect of study

design prevents any pooling of data. Six cross-over studies were quality

assessed against standards produced by Griffiths(2004) (Appendix 3).

One parallel trial was assessed against the Consort standards (Moher,

Schulz and Altman 2001) for reporting of RCTs (Appendix 4). Trials were

ranked on the following:

54

1. How participants were allocated to interventions

2. provision of scientific background and rationale for the study

3. method should include how participants were chosen, settings

where data collected, precise details of the interventions, specific

aims and objectives, primary and secondary outcome measures,

how sample size was determined

4. randomisation: technique for allocation and blinding

5. statistical methods used for primary outcome comparisons

6. results: participant flow, protocol deviations, recruitment and follow-

up, baseline demographic data, numbers analysed, outcomes and

estimation, adverse events.

7. Discussion: should include interpretation of results considering

hypotheses, sources of bias or lack of precision, statistical

problems. Should also consider generalizability. (Moher, Schulz

and Altmann 2001; Griffiths 2004)

Study design of included trials

Methodological quality was generally poor particularly regarding sample

calculations and sizes, ethical considerations, data analysis and study

design. (See appendices 3,5 and 6). All except Barnett (2002) were

crossover studies. Barnett’s study took baseline measures with follow-ups

at three and six months. Postema et al (1998) allowed subjects to wear

each intervention for a month before in-shoe pressure measures were

taken and a new intervention fitted

55

Participants of included studies

Four studies involved diabetic patients involving 200 participants

(Armstrong 1999; Barnett 2002; Fleischli 1997; Lavery 1997b).

Barnett(2002) included patients with types I and II diabetes with no history

or existing ulceration or significant pathology. Armstrong (1999), Fleischli

(1997) and Lavery (1997) studied patients with existing or recently healed

single plantar diabetic ulcers but did not specify if patients were Type I or

Type II diabetes (DM).

Hsi (1999) selected patients with treated unilateral heel pain (n=22).

Postema (1998) chose patients with primary metatarsalgia. (n=42)

Redmond (2000) included asymptotic individuals with abnormal pronation

(n=22).

Interventions studied in included trials (Appendix 7)

Eighteen different interventions were tested, excluding baseline footwear.

TCCs, the DH pressure relief walker and the PW Minor extra depth shoe

were covered by more than one paper. The quality of the papers

examining these interventions (Fleischli 1999, Armstrong 1997 and

Lavery 1997) were poor. The methods of cast construction differed.

The Four subgroups of intervention were identified: TCC’s and RCW’s,

footwear, insoles/orthoses and external shoe adaptations.

56

Outcome measures (Appendices 8 and 9)

All included trials collected mean PPP. Trials used different sampling

speeds (50 – 100hz) and different “masks” i.e. areas of the foot. Studies

examining pressure over healed ulcers sites did not explain how this was

done. PTIs were collected by four studies

Mean contact area was collected in two studies (Barnett 2002 and

Redmond 2000). This data is relevant as pressure is dependent on the

available surface area for dispersion. Only Barnett (2002) and Hsi(1999)

collected walking speed data whilst all studies asked subjects to walk at

their own pace.

Two studies used a mixed methods approach. Barnett asked subjects to

complete a Foot Health questionnaire and to keep a diary of

orthoses/insole use. Postema et al asked subjects to complete a pain

questionnaire and asked for their preference between interventions

Methodological quality

Objectives of study

Study design, in some trials, did not match objectives. Armstrong (1999)

selected patients with fore-foot ulcers to consider the impact of off-loading

devices on heel pressures. Armstrong (1999) and Fleischli (1997)

considered ulcer treatment. The inclusion of patients with healed ulcers

57

was not jusitified. Walking speeds were not collected although speed has

a bearing on repetitive stresses which delay healing and on the validity of

the study (Zhu et al 1995). Lavery (1997b) considers ulcer prevention but

includes patients with existing ulcers in the sample population. Barnett

(2002) also studies interventions to prevent ulcers and, therefore,

excludes subjects with existing or previous u

ulceration.

Two studies examine the relationship between pain and plantar pressure

distribution. (Postema 1998; Hsi 1999). Hsi (1999) does not justify

recruiting subjects who do not have heel pain and have had treatments

which might affect results. One study investigated the use of functional

orthoses to change forces acting on abnormally pronated feet. (Redmond

2000)

Quality of studies

All the cross-over trials randomised their treatment order but did not

describe how this was done. Ethical considerations were poor. Some

papers did not mention informed consent, right to withdraw or consider the

advisability of testing ulcerated individuals in sneakers. Callus reduction

was only carried out by one researcher although callus increased plantar

pressures by up to 30%. Appendix 5 assesses trials against the foot

pressure measurement protocol. (Barnett 1998)

58

Statistical considerations (Appendix 6)

Sample sizes tended to be small (Armstrong, n=25; Fleischli, n=26; Hsi,

n=22; Redmond, n=22). Sample sizes were calculated in two studies (Hsi

1999 and Barnett 2002), but no justification given for assumptions

required for the calculations. Most studies presumed an underlying

parametric distribution apart from Barnett (2002)and Redmond (2000),

who tested their data. Redmond (2000) found that some data could not

be transformed to a normal distribution and used non-parametric tests

instead. High order crossovers studies require particular procedures to

calculate sample size and power determination to take into account

potential carry-over effects from different treatments (Qu, 2003). There

was no evidence of this in the affected studies.

Six studies used repeated measures. The number of steps per subject

per modality varied from 5 – 40. (Appendix 9). These are within guidelines

(Kernozec, La Mott and Dancisak 1996)

Four studies had less than thirty subjects in their sample. An adequate

sample is required to guard against type I errors i.e. optimistically

concluding a significant difference between intervention and control. Only

Barnett (2002) stated a clear hypothesis. All studies found significant

improvements on their chosen baseline, reflecting the findings of the

literature review. This may be evidence of a publication bias in English.

Only three studies offered a power calculation (Barnett, Hsi and

59

Redmond) to assess the risk of a type II error i.e. falsely accepting the null

hypothesis.

Non-parametric tests should be used for non-normal distributions. Most

included studies did not discuss data distribution. All studies used mean

and standard deviations as descriptive statistics without justification.

Medians and ranges should be used with non-parametric data (Pett,

1997). Two studies (Fleischli 1999 and Lavery 1997) sub-divide their

sample into small, uneven groups. Pett (1997) considers that unequal cell

sizes cause serious problems for the repeated measures designs and

multivariate ANOVA’s that these studies use.

Treatment of data from right and left feet (Menz 2003) varies betweem

included studies (Appendix 10). Fleischli and Lavery investigated

pressure over single ulcer sites. Postema selected the most painful foot.

If neither foot was more painful, the choice was randomised, but the

method was not given. Barnett collected readings from ten left and ten

right steps, but later figures appear pooled as do those of Hsi. Redmond

pools data after statistical testing and justifies this, doubling of the sample

size. Armstrong does not give any figures.

Results

Total contact casts and removable cast walkers

1.Fleischli (1997) studied the effect of pressure off-loading devices

over ulcer sites of 26 neuropathic diabetics, sub-divided into

60

subjects with ulcers under the metatarsals (n=19) and those under

the hallux (n=7). The DH pressure relief walker was equivalent to

the TCC at off-loading the hallucal ulcers (79%, 85% respectively)

and more effective for metatarsal ulcers (85%, 76%). Both devices

were significantly better than the Darco OrthoWedge shoe (66%

forefoot group, 64% hallux group) , accomodative felt and foam

dressings (48% forefoot group, 34% hallux group) and the Darco

rigid post-operative shoe (36%, 7% respectively). The authors

concluded that if pressure reduction is strongly correlated with

healing, the DH pressure relief walker is an acceptable alternative

to the TCC.

2.Armstrong (1999) investigated the impact of TCCs, Aircast

pneumatic walker, the DH pressure relief walker and extra-depth

therapeutic shoes on heel pressure in 25 diabetic neuropathic

subjects with plantar forefoot ulcers. The TCC was found to be

significantly better at reducing PPP. There was no significant

difference between removable casts. Extra-depth shoes offered the

least protection. Considering PTIs, the DH walker was significantly

better than other modalities. All interventions, including the

baseline sneakers, reduced PTI significantly more than therapeutic

shoes.

The DH pressure relief walker performed well compared with TCC’s but

the areas examined differed (area of forefoot ulceration or heel pressure).

61

The methodological quality of both papers is poor. Currently debate about

patient compliance (Boulton and Armstrong 2004) suggests that patients

remove walkers, impairing clinical outcomes. TCC’s may, therefore,

remain the intervention of choice.

Shoes

1. Lavery (1997b) considered three kinds of therapeutic footwear. For

individuals with metatarsal ulcers (n=22), comfort shoes were more

effective than cross-trainers and therapeutic shoes. For those with

hallucal ulcers (n=10), extra depth shoes were equivalent to

comfort shoes and significantly better than cross-trainers.

2. Armstrong (1999) examined heel pressures (PPP, PTI and foot

contact areas) in 25 diabetic patients with forefoot ulcers whilst

wearing TTCs, RCWs and extra-depth shoes. The latter were the

least effective intervention as PTI exceeded the baseline sneaker.

The evidence for footwear from these studies is insufficient to draw

conclusions regarding effectiveness. The quality of both studies was poor.

Insoles/orthoses

Terminology was not consistent – some authors described a moulded

device as an insole, others as an orthoses.

1. Hsi (1999) studied the effect of visco-elastic heel orthoses in 22

patients with treated heel pain whilst wearing their own shoes.

62

This intervention reduced mechanical load in the posterior heel

and midfoot and increased load over the first metatarsal and

hallux during gait.

2. Postema (1998) considered the effect of two types of insole and

a rocker bar on forefoot pressures in 42 patients from several

centres across The Netherlands with a history of primary

metatarsalgia. The custom-moulded insole reduced force

impulse by 10.1% and peak pressure by 18.25% over the

central forefoot. Lower pain scores were found in patients

experiencing pain whilst wearing the customized insole and

more users expressed a preference for this intervention.

3. Redmond (2000) tested the effect of a modified Root orthosis

and a flat, non-cast insole (both with 60 varus posting) on a

sample of 22 individuals with abnormal pronation. The Root

orthosis reduced pressures and forces at the heel and

increased heel surface area. Midfoot forces remained

unchanged as an increased load was offset by increased

contact area. Forefoot pressures were also reduced leading the

authors to conclude that foot function was altered profoundly

with the Root orthosis in healthy young adults with abnormal

pronation. The choice of non-Root comparator was

questionable: a card base with EVA varus rear-foot post. This is

not a typical alternative treatment for pronation and therefore a

poor indication of the relative benefits of the modified Root

intervention. Study quality was poor.

63

4. Barnett (2002) recruited 103 neuropathic diabetic patients who

were randomised to receive 3mm unadapted Cleron insoles or

off-the-shelf polyurethane and EVA moulded orthoses for six

months in their own footwear. Plantar pressures were assessed

at baseline, three and six months. Orthoses reduced PPP by

22%, PTI by 16% and increased mean contact areas by 11%.

The Cleron insoles (designed as a “blind” and for control

purposes) also reduced PPP (16%),and PTI (10%). Mean

contact area was increased by 2%. The author concluded that

Cleron insoles were successful at reducing pressure in

individuals with diabetes and neuropathy but without substantial

foot deformity. Pre-formed orthoses were suitable for patients

with higher planter pressure and increased risk of ulceration.

Foot health questionnaires suggested that orthoses improved

subjects’ perception of foot health. Compliance appeared to be

good. Gait speed increased significantly in both sub-groups.

5. Lavery (1997) investigated the effect of footwear with and

without an unmodified 4 mm plastazote/urethane insole on

mean peak pressure in a sample of 32 subjects with existing or

recently healed diabetic, neuropathic plantar ulcers. The

insoles reduced mean peak pressures at ulcer sites by an

additional 5.4 – 20.1% from baseline and a similar trend was

observed at non-ulcerated areas of the foot. Study quality was

poor.

64

Included studies concluded that one or more insoles/orthoses were

effective at redistributing PPP, reducing PTI (where collected) and

increasing contact areas in a variety of populations. The case for custom-

moulding over “off-the-shelf” shoe inserts was very limited. Simple insoles

had significant impact on pressure variables. Moulded insoles were well-

received.

Visco-elastic heel orthoses appear to distribute pressure away from the

heel to the 1st MTPJ and hallux in a small group of subjects with treated

heel pain.

External shoe adaptations

1. Postema et al (1998) tested rocker soles with 42 patients with

primary metatarsalgia. Force impulse was reduced over the lateral

and central metatarsal heads by 10.5% and 15.1%. PPP was

reduced by 7.6% and 15.7% over the same areas. The addition of

insoles produced further off-loading which was independent of the

rocker sole. The sample composed of 41 women out of 42

subjects. The authors do not describe metatarsalgia as confined

exclusively to women. This sample is, therefore, biased.

There is limited evidence from a moderate quality multi-centre RCT that

rocker soles reduce forefoot pressure in a sample of women with primary

metarsalgia.

65

Discussion

Heterogeneity of studies made pooling results impossible. Methodological

quality was generally poor. Qualitative synthesis provides reasonable

evidence from one RCT that insoles/orthoses are effective in redistributing

plantar pressure. Evidence for TTCs, RCW and footwear is very limited

because of small sample sizes, unique studies and poor quality. There is

limited evidence that a version of the rocker sole reduces loading over the

metatarsals. Visco-elastic heel pads redistribute pressure away from the

heel in one small study.

Comparing the results for the diabetic studies with those of Spencer

(2000) on preventing and healing diabetic ulcers, some similarities

emerge. In preventative studies, orthotic devices appeared effective in

preventing ulcers and treating callus. There was limited evidence that

TCC’s are effective in treating ulcers. No trials of RCWs were identified.

Preventative studies were underpowered.

Crawford and Thomson’s (2003) review of interventions for treating plantar

heel pain found little evidence for treatment (including heel pads and

orthoses) over no treatment.

Both reviews mention small sample sizes and the need for multi-centred

RCT’s to reduce the risk of Type I errors. Similarly, in this review, study

groups were generally small and only one (Postema 1998) was multi-

centred. Poor methodological quality was typical of included studies.

66

The objective of the review was to consider whether footwear, orthoses

and casts redistributed plantar pressure. Reviewed literature generally

supports this. This suggests either an overwhelming case has been

made, many Type I errors or a publication bias in English language

literature towards releasing only positive results. Better quality research is

required to clarify this.

Work started by the Foot Pressure Interest Group in providing protocol

guidelines based on research and best practice goes some way towards

providing consistency between studies and should be more widely

adopted. Three trials (Armstrong 1997; Fleischli 1999 and Lavery 1997)

were by the same team of researchers and showed many similarities.

Fleischli (1999), in particular, cites heavily from the team’s output (14 from

28 cited papers). There are potential benefits in developing consistent,

good quality protocols but there are dangers if the template devised is

poor (all three studies scored low) and if poor research is then repeatedly

repackaged.

Most studies did not evaluate the long term effects on subjects and

interventions. Barnett (2002) noted quite rapid degradation of

interventions over 6 months. A synergy was noted between insole and

shoe as the insert moulded to the individual foot and shoe shape and

walking speed increased in subjects with moulded orthoses. These

67

outcomes are worth investigating further. A general weakness of ethical

considerations in some studies was a concern.

A mixed methods approach demonstrated benefits in the two studies

using it, suggesting the weakness of the link between pressure and pain

(Postema 1998) and to identify factors affecting patient compliance.

(Barnett 2002) Qualitative research can be a valuable adjunct to

quantitative studies.

Shear stress may be important in understanding the limited correlations

found between pressure and pain or pressure and ulceration. It is a

weakness of current in-shoe technology that shear stress cannot be

measured.

The evidence suggests that footwear and orthoses redistribute plantar

pressure but the value of this to clinical practice is unclear as there is no

conclusive evidence that the pressure variables measured are the most

significant in treating the insensate or painful foot.

Weaknesses in the study

The review is weakened by being single-authored. This may have

introduced bias into the search, selection and review of the literature. A

lack of specificity during searching may have resulted in relevant studies

being missed. Limiting the review to research in English may have

68

introduced a publications bias. The use of unpublished literature is also

weak.

Reviewer’s conclusions

Implications for practice

There is evidence from a single centre RCT that simple cleron insoles are

an effective intervention for pressure reduction in low risk diabetic patients

and moulded inserts are appropriate for higher risk patients without foot

deformity. The insoles deteriorated significantly over 6 months and

should be replaced regularly. Research is required to assess the most

effective and efficient time scale.

Visco-elastic heel orthoses appear to distribute pressure away from the

heel to the 1st MTPJ and hallux in a small group of subjects with treated

heel pain

There is limited evidence from a small unique trial that rocker soles reduce

plantar pressure over the central metatarsals in women with primary

metatarsalgia.

Implications for research

.

• Multi-centre large scale RCTs are required to evaluate the

effectiveness of footwear, orthoses and casted devices for the

treatment of the insensate and painful foot.

69

• development of standard measures and research protocols is

urgently required to improve comparison of outcomes.

• Further research is needed to identify significant pressure

variables.

70

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Appendix 1:Draft protocol guidelines: in-shoe measurement

(Barnett 1998)

Standardisation of Report

• system specifications (thresholds) should be standardised

• floor surface

• data collection run

• socks

• velocity

Manufacturers’ protocols

• should be acknowledged and understood

• usually require acclimatization, bedding in and in-shoe calibration

• should be stated in reporting

Floor and walkway

• should be non-slip, flat, level and stable

• a figure of eight if possible

• protocols should excluded acceleration and deceleration data

• data should be recorded mid-cycle

• PC and wires should not distract

Footwear

• For longitudinal studies, standardised, manufacturer supplied

footwear should be used, depending on research question

92

• For intervention studies, patient’s own comfortable shoes should be

used. Should be classified and the degree of wear noted.

• Should reflect real-life footwear

Socks

• Pop socks (thin nylons)

• Dressings removed and film dressings used to cover wounds

Callus

• State whether callus has been removed and why. Should apply to

all subjects

Walking speed

• Self-selected at comfortable pace decided by subject

• Velocity noted and reported

Inserting and removing insoles

• Controlled by researcher

• Allow for bedding in

Calibration

• Reflect real-life, not rely on bench testing

• Follow manufacturers’ guidelines and publish these.

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Appendix 2: Indexed terms from papers checked against inclusion

and exclusion criteria

Participants: adults; human; military personnel; diabetic foot [prevention

and control]; diabetic foot[therapy]; foot[physiology]; gait[physiology],

aged; metatarsalgia; cumulative trauma disorders[prevention]; foot

disease[complications]; obesity[complications]; pain[physiopathology];

pain[therapy]; diabetes mellitus; foot deformities [acquired]]; foot disease

[complications]; plantar fasciitis

Interventions: Orthoses; foot: sport shoes; casts: casting: device; shoe;

foot orthoses; orthotic devices; shoes; shoes [adverse effects]; cast,

surgical; metatarsophalangeal joint; foot sole; forefoot [human]; metatarsal

bone; polyurethanes; silicones; metatarsus; heel

Outcomes: Pressure measurement; pressure; transducers; pressure

sense; weight-bearing; piezoelectricity; sensor; force; stress, mechanical;

running; risk factors; patient satisfaction; risk assessment; walking; body

weight; gait; activities of daily living; ankle pressure; physical stress.

Study Design: controlled study; quantitative diagram; analysis of

variance; crossover studies; double-blind method; multivariate analysis;

clinical trials; conference paper; major clinical study; cohort studies

94

Appendix 3: Crossover trials assessed against quality criteria

(Griffiths 2004)

Armstrong Fleischli Hsi Lavery Postema Redmond

Is the research question

clearly focussed?

0 2 2 2 2 0

Is the study grounded on an

adequate knowledge base?

1 0 2 2 2 2

Was the research

methodology appropriate

for the research issue?

1 2 1 2 2 2

Was the study design

appropriate to the issue?

1 2 2 0 2 0

Were ethical issues

recognised and addressed?

0 0 2 0 0 0

Was the sampling strategy

appropriate and clearly

explained?

1 0 2 2 1 0

Were all of the participants

accounted for at its

conclusion?

2 2 2 0 2 2

Were there clear inclusion/

exclusion criteria?

1 0 2 0 1 0

Were measures taken to

reduce bias?

0

Sampling procedures 0 0 2 0 1 1

Intervention Protocol 1 1 1 0 2 2

Was the data collection

method sound?

1 0 1 0 1 0

95

Was the data analysis:

Appropriate 0 0 1 0 1 0

Clearly described 0 0 1 0 1 2

Justified 0 0 1 0 1 2

Is there sufficient detail to

assess the credibility of the

findings?

0 0 1 0 1 0

Can the findings be applied

to your situation?

0 0 1 0 2 0

Were all clinically important

outcomes considered?

0 0 1 2 1 1

Are the benefits worth the

harms and costs?

0 0 1 0 2 0

9 9 26 10 22 14

Coding: 0= not met Quality < 20 = poor

1= partly met 20-30= moderate

2= well met > 30= good

Possible total =36

96

Appendix 4 Parallel trial (Barnett 2002) assessed against Consort

Statement (Moher, Schulz, and Altman (2001)

1. title and abstract: prospective randomised clinical control trial.

Participants randomly assigned to EVA orthoses or 3 mm Cleron

insoles. Qualitative research on patient perception of foot health

and diary of wear. Longitudinal study (6 months)

2. Introduction/background: thorough

3. Participants: clear inclusion and exclusion criteria. Location of data

collection unclear

4. Interventions: control: 3mm cleron insole, intervention: non-

customized, pre-formed, TEC urethane orthoses with EVA cover.

Used in patients’ own shoes between readings. Measures taken at

baseline, 3 months and 6 months in standardized shoes

5. Objectives: specific hypothesis, clear objectives

6. Outcomes: peak plantar pressure and pressure time integral (whole

foot and 9 masks). Foot contact area, walking speed. Bristol Foot

health questionnaire, diary of use. Measures taken from 10 right

steps and 10 left steps. Calibration and acclimatization reported.

Callus debrided, standard nylon socks, lesions covered with Opsite.

Thickness of insoles/orthoses recorded at baseline and follow-ups

to assess degradation. All assessments by lead researcher.

7. Sample size: a priori power calculation of 47 subjects per group.

103 participants recruited.

97

8. Randomization: letters in envelope in box. Subjects assigned as

recruited.

9. Allocation concealment

10. Implementation: see 8.

11. Blinding: control group also an intervention. Both groups told

contributing to research. Not double-blinded

12. Statistical methods: normal distribution assessed, used ANOVA for

multivariate analysis

13. Participant flow: described, including drop-out from each group with

reasons. No diagrammatic representation of flow

14. Recruitment: dates not given. Intervals of follow-up given

15. Baseline data: provided in detail for both groups. Cleron group

significantly older than intervention group.

16. Numbers analysed: 117 recruited, 14 left study before completion –

reasons explored. Data analysed on “intention to treat” basis

17. Outcomes and estimation: results summary provided for each

group, by mask areas and whole, by foot type, for participants with

above average pressures for group. P= 0.01

18. ancillary analyses: developed, trialled and used Bristol Foot Health

Quesionnaire. Results reported. Diary of use information

assessed for patient compliance and patient comments on ease of

use, comfort, etc.

19. Adverse events: causes of drop-out. Discomfort with Cleron

explored. Increased walking speeds in both groups, particularly

98

with orthoses. Possible causes discussed: confidence with testing,

improved foot functionality

20. Interpretation: would like more time to consider increased walking

speeds. Changes to interventions over time not adequately

predicted by thickness. Problems with sensor resolution over digits

with Emed Pedar. Differences between actual and expected

outcomes discussed. Similarities/difference with earlier literature

explored. Statistics used appropriately.

21. generalizability: good. Inclusion criteria sufficiently broad to allow

clinical application to the majority of DM patients without major

complications or deformity

22. overall evidence. Good. Only longitudinal study.

Appendix 5:Trials assessed against Protocol for foot pressure

measurement

Armstrong Barnett Fleischli Hsi Lavery Postema Redmond

Manufacturer'sProtocols no yes no yes no no no

Floor/walkway no yes no no no yes yes

Footwear no yes no yes no yes no

Socks no yes no no no no no

Dressings no yes no n/a no n/a n/a

Callus no yes no no no no no

Mid-gait steps yes yes yes yes yes no yes

self-set speed yes yes yes yes yes yes yes

Walking speed no yes no yes no no no

insert/remove insoles no yes no yes no no no

Calibration no yes no yes no no no

99

Appendix 6: Statistics

sample size calc Power calc Stats test

Armstrong No Yes

ANOVA and tukey’s post hoc

studentized range test

Barnett Yes Yes

t-tests for matched pairs,regression

analysis

Fleischli No No

Univariate and multivariate ANOVA and

tukey’s

Hsi Yes Yes

two-factor ANOVA, F-test for

significance, coeffs of reliability and

variability

Lavery No No

Univariate and multivariate ANOVA.

Tukey and Paired T-Tests

Postema No No

Paired T-Test for repeated measures.

Multivariate ANOVA. One –sided

Fisher exact tes

Redmond No Yes

Checied distribution for normalality.

ANOVA Friedman and Wilcoxon for

non-ratio data

100

Appendix 7: Interventions studied in included trials

Armstrong Barnett Fleischli Hsi Lavery Postema RedmondViscoelastic Heel orthoses

X

Standard insoles (6.5 mm polymeric foam flat inserts

X

Custom-made Insoles (6.5 polymeric foam)

X

Rocker Bar X TCC X X Darco orthowedge/half shoe

X

Darco rigid post-op. shoe

X

DH pressure relief walker

X X

Accomodative foam and felt dressing

X

Card insole with 60 EVA varus rearfoot post

X

Modi Root orthosis polypropylene shell with PVC cover and 60 EVA varus rearfoot post

X

Cleron insole: 3mm flat insert

X

EVA (off the shelf” moulded orthoses

X

Aircast pneumatic walker

X

Extra depth shoes with PW Minor inlays men/ women

X

SAS comfort shoes for men and women

X

New Balance cross-trainers for men and women

X

Plastazote/urethane insole, preformed

X

Baseline Footwear Reebok sneaker X Standard orthopaedic shoe

X

Rubber soled canvas oxford

X X

Own shoesx X Dunlop athletic shoes

X

Socks unknown Thin nylons

No socks

Own socks

Unknown unknown unknown

101

Appendix 8: Variables collected in included studies

Armstrong Barnett Fleischli Hsi Lavery Postema RedmondPeak Pressure N cm2 kPa cm2 N cm2 kPa cm2 Ncm2 Ncm2 kPa cm2

Pressure time integral N.s/cm2 Kpa.s/cm kPa.s/cm2 kPa.s/cm2

Mean contact area Cm2 Cm2

Average step length x Average step time x Walking speed x x Foot to sensor contact time x Force impulse x Force time integral x Maximum force x Bristol foot health questionnaire x Diary of wear x Pain questionnaire x Patient preference x

102

Appendix 9: Masking and sampling speed data

Armstrong

Heel pressures collected. Masking not specified. Sampling

speed not specified

Barnett 9 regions of foot masked and whole foot. Sampling speed 99 Hz

Fleischli

Pressure over existing or former ulcers: masking not described.

Sampling speed 50 Hz

Hsi Parotec. Over whole foot. Sampling speed 100 Hz

Lavery

Pressure at ulcer sites and hallux, 1st met and 2nd-5th met

Masking not described

Sampling speed 50 Hz

Postema

Pressure over four regions of forefoot, established using Emed

platform. Sampling speed 70 Hz with Emed Mikro

Redmond

Six masks over whole foot – lateral digits discarded. Sampling

speed 50 Hz

Appendix 10: Use of data from Right/Left feet (Menz 2003)

Armstrong (1999)

Does not specify if pressures are taken for both feet and pooled or

only the ulcerated foot.

Barnett (2002)

Tests 10 right steps and 10 left steps for each participant at

baseline and each follow-up but appear to pool data.

Fleischli (1997)

103

104

Mean peak pressures over the site of ulceration. Sample size

implies one ulcer per subject and therefore assume only ulcerated

foot is included in study but not specified.

Hsi(1999)

Studies 22 consecutive patients with unilateral heel pain. Assume

that only data from painful heel is used but not specified.

Lavery(1997)

32 consecutive patients with diabetes and recent or existing

neuropathic ulcer. Pressure measured over ulcer. Presume one

ulcer per patient but not specified.

Postema (1998)

42 primary metatarsalgia patients. Specified use of the most

painful foot or – if no pain – a random choice is made (method not

specified). Explicit states that this is to avoid dependency of

measurement.

Redmond(2000)

Tested 22 patients with abnormal pronation. Tested results from

right and left, found no statistical difference and therefore pooled.