correlation of radio graphic changes after tibial tuberosity

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Correlation of Radiographic Changes after Tibial Tuberosity

Advancement in Dogs with Cranial Cruciate-Deficient Stifles

with Functional Outcome

Joe P. Morgan1, DVM, Diplomate ACVR, Katja Voss2, Dr med vet, Diplomate ECVS,

Daniel M. Damur3, Dr med vet, FVH, Diplomate ECVS, Tom as Guerrero2, Dr med vet, Diplomate ECVS,

Michael Haessig4, Prof. Dr med vet, and Pierre M. Montavon2, Prof. Dr med vet

1Section of Diagnostic Imaging and Radio-Oncology, Vetsuisse Faculty University of Zurich, Zurich, Switzerland, 2Clinic for Small Animal Surgery

Vetsuisse Faculty University of Zurich, Zurich, Switzerland, 3Tierklinik Masans, Chur, Switzerland and 4Department for Farm Animals, Vetsuisse

Faculty University of Zurich, Zurich, Switzerland

Corresponding Author

Katja Voss, Dr med vet, Diplomate ECVS,

University Veterinary Teaching Hospital

Sydney, 65 Parramatta Road, Camperdown

2006 NSW, Australia

E-mail: [email protected]

Submitted April 2009

Accepted January 2010

DOI:10.1111/j.1532-950X.2010.00669.x

Objective: To (1) evaluate radiographic changes associated with osteoarthrosis

(OA) before and after tibial tuberosity advancement (TTA) and (2) determine if

these changes are indicative of limb function as determined by kinetic gait

analysis.

Study Design: Prospective clinical study.Animals: Dogs (n=35) with cranial cruciate ligament (CCL) deficient stifles (38).

Methods: Variables recorded were: complete or partial CCL rupture, meniscal

lesions, arthroscopically graded cartilage lesions, complications, and revision

surgeries. Radiographic evaluation and kinetic gait analysis (vertical ground

reaction forces [GRFs]) were conducted pre- and 416 months postoperatively

(mean, 5.9 months). Radiographs were evaluated without knowledge of operative

findings and functional outcome. A score (03) based on new bone production at

11 specific sites was used to grade OA. Soft tissue changes were classified

separately as normal or excessive. Preoperative scores were correlated with clinical

variables. Postoperative scores and progression of OA scores were correlated with

clinical variables and GRFs.

Results: OA remained unchanged in 17 joints and progressed in 21 (55%). Dogs

with meniscal lesions had higher OA scores preoperatively, but not at follow-up.Dogs with severe cartilage lesions at surgery had more progression of OA. GRFs

improved after surgery and were not correlated with any of the radiographic OA

scores.

Conclusion: Progression of OA was greater in the presence of severe cartilage

lesions at surgery. OA scores were not correlated with GRFs.

Clinical Relevance: Progression of OA is generally expected to occur after TTA

despite improvement of limb function.

Partial and complete rupture of the cranial cruciate liga-ment (CCL) occurs frequently in dogs and results in insta-bility and secondary osteoarthritis (OA).18 Presence andprogression of radiographic changes of OA in the stiflejoint of the CCL-deficient dog has been reported after con-servative treatment 4,9 and after extracapsular or intracap-sular substitution techniques7,1015; tibial plateau levelingosteotomy (TPLO)1519; and tibial tuberosity advancement(TTA).20 Radiographic soft tissue changes include jointeffusion/capsular thickening, lateral and medial soft tissuethickening, intraarticular osseous fragments, and meniscalmineralization.14,18 Bony changes include osteophytosisand enthesiophytosis, subchondral sclerosis, subchondral

cyst formation, and joint space narrowing,7,14,15,18,21 gener-ally placing emphasis on presence and growth of marginalosteophytes. Patellar ligament thickening and patellar ten-dinosis have also been evaluated after TPLO.19,22,23

Surgical techniques that change the geometry of theproximal aspect of the tibia, such as TPLO and TTA weredeveloped to restore functional stability of the stifle, pre-vent deterioration of the medial meniscus, and reduce thedegree of secondary OA in the stifle joint with CCL rup-ture.24 The initial hope that progression of OA could beminimized using these techniques has not been realized.Whereas progression of OA is less in dogs after TPLO thanafter extracapsular stabilization,15 in general, progression

Veterinary Surgery 39 (2010) 425432 c Copyright 2010 by The American College of Veterinary Surgeons 425
mailto:[email protected]:[email protected]


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of OA has been observed after both TPLO and TTA.1620

Radiographic progression of OA after TTA has not been

reported in detail, nor is it known whether certain clinicalfactors correlate with development of degenerativechanges.

Outcome after surgery for CCL disease can be assessedbased on the radiographic progression of stifle joint OA

and by evaluating functional outcome, which is probablythe clinically more relevant outcome measure. Whereas ra-diographic changes have been used as a standard clinicaltool to evaluate progression of degenerative disease,7,18,25

their identification does not necessarily relate directly toclinical functional outcome.10,17 Several studies have re-ported or suggested a lack of significant correlation be-tween the radiographic appearance of OA and clinicalevaluation of limb function.5,7,9,18,26 Postoperative clinicalstatus has been judged using lameness evaluation by a cli-nician or by an owner assessment at various intervals aftersurgery.18,20,27,28 This type of assessment is subjective andmay not necessarily reflect the effective functional out-

come. Force plate gait analysis is a more objective methodto classify gait, and has been used to demonstrate clinicaleffectiveness of several treatment techniques in dogs withCCL disease.2932

Our purpose was to record the presence and progres-sion of both bony and soft tissue radiographic changes oc-curring after TTA, and to evaluate potential risk factors forOA progression after surgery. The influence of the leveland progression of radiographic OA on functionaloutcome was determined by force plate gait analysis. Wehypothesized that severity and progression of stifle OA

would not be an indicator for functional outcome as deter-mined by vertical ground reaction forces.

MATERIALS AND METHODS

Dogs

Dogs (n = 35; weighing Z20 kg) with a partial or completeCCL rupture that had TTA (n = 38) between May 2003and December 2004 were studied. These dogs were part ofthe population of an earlier study of consecutive patientswith CCL disease that had been treated with TTA.32 Twoof the original 37 dogs were excluded because of incom-plete radiographic studies.

Clinical Evaluation

All dogs had arthroscopic stifle examination before TTA.Synovial membrane biopsies were taken at the beginning of

the arthroscopy from the medial aspect of the joint capsuleusing 2.7 mm arthroscopic spoon forceps (Dr. Fritz Instru-ments, Tuttlingen, Germany). Samples were stained with

hematoxylin and eosin and examined by light microscopy.The retropatellar fat pad was partially removed to increasevisibility. The intraarticular structures were explored forpartial or complete CCL tears, meniscal lesions, and to

classify femoropatellar joint cartilage lesions by a modifiedOuterbridge grading scale.33 Dogs with meniscal lesionshad a medial parapatellar arthrotomy for partial meniscec-tomy. TTA was then performed as described.32,34

Table 1 Summary of Radiographic Results for New Bone Production and Soft Tissue Changes in 35 Dogs with 38 CCL-Deficient Stifles that had TTA

New Bone Production Soft Tissue Changes

Preoperative

Follow-Up

(Mean, 5.9 months) Progression

Primary

Localization Progression

Global scores

03 13 7

410 18 16

1133 7 15

OA progression

None 17

14 9

510 11

410 1

11 joint involved

Femoropatellar 11

Femoropatellar and femorotibial 16

Femorotibial 3

Soft tissue changes

None 5

None preoperatively, present on follow-up 4

Present preoperatively unchanged on follow-up 19

Present preoperatively, worse on follow-up 6

Present preoperatively, decreased on follow-up 4

Numbers = Stifle Joints.

CCL, cranial cruciate ligament; TTA, tibial tuberosity advancement; OA, osteoarthritis.

426 Veterinary Surgery 39 (2010) 425432 c Copyright 2010 by The American College of Veterinary Surgeons

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Radiographic Evaluation

Mediolateral and caudocranial radiographic projectionswere evaluated presurgically, immediately postoperatively,and at a final follow-up study planned 46 months afterTTA. Mediolateral views were obtained with the stifle jointin 1201351 extension, Caudocranial radiographs were

made with the central X-ray beam at 151 proximal/distalangle. Pre- and postoperative radiographs were taken withdogs anesthetized and for follow-up studies, dogs were se-dated. Radiographic exposure was controlled by of use of adigital system and hard copies were made of each exposurefor examination. Evaluations of the degree and progressionof OA and soft tissue changes were made by a board cer-tified radiologist (J.P.M.), aware of signalment of the dogsand the time of follow-up, but unaware of the intraopera-tive findings and the functional outcome of the dogs.

New bone production, including enthesiophytes andosteophytes, was noted at 11 specific anatomic locations:apical patella, basilar patella, trochlear groove just proxi-mal to the patella, lateral femoral trochlear groove, medial

femoral trochlear groove, medial femoral condyle and ep-icondyle, lateral femoral condyle and epicondyle, inter-condyloid fossa, medial tibial plateau, lateral tibial plateau,

and caudal tibial plateau. New bone production at a spe-cific site was graded 0 when not identified, and 13 whenpresent, based on the amount of new bone, as indicated bybone density in addition to bone thickness. A total score of

0 indicated no evidence of new bone production within the joint, whereas 33 indicated extensive new bone at all 11sites. Three groups were formed based on scoring intervals:

03, 410, and 4 10 (Table 1).For evaluation, preoperative scores were compared

with final scores. For statistical analysis, data were treated

individually as well as being divided in a manner that sep-arated those with no progression, minimal progression (in-crease in score of 14), those with moderate progression(increase in score of 4 510), and those with marked pro-gression in the new bone production during the study (in-crease in score of 4 10; Table 1).

Soft tissue changes included joint effusion/capsular

thickening, lateral and medial soft tissue thickening, intra-

articular osseous fragments, and meniscal mineralization.

Changes were scored as normal or excessive. Detection of

joint capsule distention and joint effusion was based on

caudal distention of the joint capsule as evident on the lat-

eral view or displacement of the collateral ligaments on the

caudocranial view. Detection of joint capsule distention

and joint effusion was also determined as excessive if theretropatellar fat pad was o 1 cm in width, when measured

at its widest site on a mediolateral view. For statistical

analysis 5 groups were formed (Table 1). In group 1, find-

ings were negative on pre- and postoperative studies; in

group 2, findings were negative on preoperative studies and

positive on postoperative studies; in group 3, findings were

positive on preoperative studies and positive unchanged on

postoperative studies; in group 4, findings were positive

on preoperative studies and positive and progressive on

postoperative studies; and group 5, findings were positiveon preoperative studies and positive but regressive on post-

operative studies.

Force Plate Gait Analysis

Force plate gait analysis (Force plate OR6-7 from Ad-

vanced Medical Technologies Inc., Watertown, MA) wasconducted preoperatively and at final follow-up examina-tion at trotting velocity, as reported earlier.32 Trial velocitywas within 1.852.15 m/s, with an acceleration/decelera-tion o 0.5 m/s2. Peak vertical forces (PVF) and verticalimpulses (VI) of 5 valid trials were recorded for each pelviclimb and were expressed in percent of bodyweight (%BWfor PVF; %BW s for VI). PVF and VI were defined to bezero in dogs not using the affected leg at a trotting gait.

Statistical Analysis

Results from descriptive statistics are reported as meanSEM.Data were analyzed using statistical software (StatView5.1, SAS Inc., Wangen bei Dubendorf, Switzerland).Normality test (StatView 5.1) was applied before paramet-ric test if used. Preoperative radiographic scores were com-pared between dogs with partial and complete CCLrupture, between dogs with and without meniscal lesions,and between the different grades of cartilage lesions seenduring arthroscopy using factorial ANOVA.

The influence of partial or complete CCL rupture,presence of meniscal lesions, grade of cartilage lesions atthe time of surgery, and presence of complications and re-vision surgery on progression of OA was examined usingANOVA for the absolute bony radiographic scores, andw2-test for the progression categories of both bony and soft

tissue lesions. Linear regression analysis was used to de-scribe the relationship between body weight and progres-sion of OA.

Radiographic OA scores were compared with func-

tional outcome represented by PVF and VI at follow-up.Linear regression analysis evaluated the relationship be-tween the bony OA scores determined on both the preop-

erative and follow-up radiographs, and PVF and VI atfollow-up. Linear regression analysis was also used to eval-uate the relationship between progression of bony OAchanges and PVF and VI at follow-up. Additionally,

ANOVA was sued for evaluation of bony progression cat-egories and PVF and VI at follow-up, and for soft tissuechange categories and PVF and VI at follow-up. A post

hoc Bonferroni Dunn test was used for further evaluation ifsignificant differences were found between group means.Significance was set at P .05.

RESULTS

Clinical Results

Mean body weight of the 35 dogs (38 TTA) enrolled in thestudy was 33.7 kg 1.19kg (range, 21.453.3 kg). Complete


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CCL rupture was identified in 28 of 38 stifles, and partialrupture in 10 stifles. Meniscal lesions found in 21 stifleswere treated by partial meniscectomy. Femoropatellar car-tilage lesions were seen in 32 stifles and were graded33

as chondromalacia in 20 stifles (grade 1), fibrillation in 8stifles (grade 2), and fissuring in 4 stifles (grade 3). Postop-erative complications occurred in 10 joints. Revisionsurgery was performed in 5, including second lookarthroscopy or arthrotomy in 3, and revision of implants

in 2 stifles. Thirty-three synovial membrane biopsies wereconsidered suitable for histologic examination. A predom-inance of lymphoplasmacellular infiltrates was found in20 biopsies (60.6%), and unspecific synovitis with villoushypertrophy and/or hyperemia in 10 (30.3%). Threebiopsies (9.1%) had normal synovial tissue. The follow-up radiographic study and force plate analysis were con-ducted between 4 and 16 months (mean, 5.9 months) afterTTA.

Figure1 Immediate postoperative (A and B) and 5-month follow-up (C and D) radiographs of a 9-year-old mixed-breed dog with a unilateral completecranial cruciate ligament rupture and medial meniscal lesion. This dog was classified to have no progression of new bone production.

Figure2 Immediate postoperative (A and B) and 4-month follow-up (C and D) radiographs of a 5-year-old Boxer with a complete cranial cruciate

ligament rupture without meniscal lesion. This dog had a 10-point progression of radiographic scores indicating new bone production.




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Radiographic Findings

Preoperative bony changes were scored between 0 and 3 in13 joints, between 4 and 10 in 18 joints, and 4 10 in 7joints (mean, 6.16 0.93). Bony changes on follow-up werescored between 0 and 3 in 7 joints, between 4 and 10 in 16joints, and4 10 in 15 joints (mean, 9.63 1.06). There was

no progression of new bone noted in 17 joints (Fig 1), pro-gression between 1 and 4 points in 9 joints, progression be-tween 5 and 10 points in 11 joints (Fig 2), and progression410 points in 1 joint. Mean progression of new bone pro-duction was 3.34 0.73 (Table 1).

The radiographic patterns noted on the final studywere: (1) new bone production around the femoropatellarjoint, in particular, the abaxial surfaces of the trochlea, thefemur just proximal to the trochlea, and the distal apex ofthe patella; (2) enthesiophytes at the attachment of the col-lateral ligaments on the femoral epicondyles and the periar-ticular area of the tibia plateau; (3) new bone from theepicondylar region extending toward the abaxial surfaces ofthe trochlear notch; and (4) minimal new bone at the inter-

condylar fossa. Distribution by principal joint involvementwas: femoropatellar joint (11), femoropatellar and femoro-tibial joints (16) and femorotibial joint (3). In 8 joints, OA

changes were not sufficiently prominent to place the jointinto a distinct pattern (total score, 3).

Soft tissue changes, in particular joint effusion or cap-sular thickening was less evident than bony change, but

was considered present in 29 joints before, and in 33 jointsafter, surgery. Progressive soft tissue change occurred in 10 joints, while 19 had similar scores before and after TTA

(Table 1).

Force Plate Results

Preoperative PVF ranged from 0% to 64.6% BW (mean,31.5 3.67% BW) and preoperative VI from 0% to 9.4%

BW (mean, 4.2 0.49% BW). PVF at follow-up were be-tween 49.4% and 85.2% BW (mean, 65.0 1.27% BW)

and VI ranged from 6.4% to 10.9%BW (mean,8.4 0.18% BW). One-way ANOVA revealed no differ-ence in ground reaction forces of 27 limbs that had a fol-

low-up between 4 and 6 months, and 11 limbs that had afollow-up between 6 and 16 months.

Statistical Results

Preoperative bony radiographic OA scores were signifi-cantly greater in dogs with meniscal lesions compared withdogs without (P = .04), but did not differ between dogswith partial or complete CCL ruptures, and between differ-ent cartilage lesion grades.

Bony radiographic OA scores at follow-up and pro-gression of bony radiographic scores did not depend onpresence of partial or complete CCL rupture, presence orabsence of meniscal lesion, presence or absence of surgicalcomplications, or revision surgery. The grade of cartilagelesion at time of surgery was statistically associated with

progression of bony OA scores (Po .01; Fig 3). Dogs withgrade III cartilage lesion had a significantly higher progres-sion of OA scores compared with dogs with grade I(P = .001), and dogs with grade II (P = .0013) cartilage le-sions (Bonferroni/Dunn test, significance at Po .0083).None of the variables tested was statistically associatedwith presence and progression of radiographic soft tissuechanges.

Neither preoperative radiographic bony OA scores,bony OA scores at follow-up, progression of bony scoresthroughout the study, nor categories of soft tissue changeswere associated with functional outcome represented byPVF and VI at final follow-up examination.

DISCUSSION

We found that 55% of treated stifles had progressive OA

within 416 months of TTA, which is similar to other re-ports where approximately half of the treated dogs devel-oped progressive OA after TPLO16,18 or TTA.20

Preoperative radiographic OA scores were significantlygreater in dogs with meniscal lesion than in dogs with intactmenisci in our study. Higher radiographic scores usually in-dicate chronic disease and it is possible that meniscal lesionswere more common in chronic cases because they had moretime to develop. It is also possible that meniscal lesions re-sulted in faster progression of OA. Preoperative radio-graphic scores did not differ between dogs with partial andcomplete CCL rupture. This is somewhat surprising, be-cause when assuming that CCL disease in large-breed dogsis degenerative in origin one would expect a higher degree ofOA in dogs with complete CCL rupture. However, somedogs with complete CCL rupture had no, or only minimal,signs of OA on admission, which suggests an acute, andpossibly traumatic CCL rupture in these dogs.

Meniscal release and caudal pole hemimeniscectomyresult in changes of pressure distribution and in increased

Figure3 Diagram showing the relation between progression of bony

osteoarthritis (OA) scores and grades of cartilage lesions as determined

during arthroscopy. Dogs with grade III cartilage lesions (4 dogs) had

significantly greater progression of OA scores (Po .01) compared with

dogs with grade I (20 dogs), grade II (8 dogs), and no cartilage lesions

(6 dogs).




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stresses within the medial compartment of the stifle joint,35

and this has been suggested as a potential risk factor for

development of OA in affected stifle joints. We did not ob-serve statistically significant differences in degree of OAprogression between dogs with meniscal lesions that were

treated by partial meniscectomy and dogs with intact men-isci. There was also no difference in OA progression

between dogs with partial or complete CCL rupture. Thesefindings could of course change with longer follow-up times.

Radiographic scoring systems may not necessarily re-flect the true severity of OA. The radiographic featuresidentified in OA have classically included new bone pro-duction, bone lysis, bone sclerosis, and soft tissuechanges.7,14,15,36,37 Thus, scoring systems have been usedin various ways. Usually each determinant within the sys-tem has been assigned an equal value with the score depen-dent upon the severity of the change. Scores were thentotaled for a cumulative global score. This was carried outwithout consideration of the ease in detection of the deter-minant in OA or whether the determinants should in fact

have equal value. An unexpected decrease in score for ex-ample could be the result of remodeling or maturation ofosteophytes that gave the impression of decreased level ofosteophytosis14 or the result of the use of soft tissue vari-ables that were more evident postoperatively than later inthe study.14,15 In addition, radiographic studies are com-promised by morphologic distortion, geometric magnifica-tion, and superimposition of bony changes.

We made no attempt to produce a global score for softtissue changes and bony changes to indicate the level of OAbecause of the lack of knowledge of appropriate weighting

of individual features. Rather, we chose to use a combina-tion of scoring systems.7,14,15,36,37 We acknowledge that thescore indicating the level of OA was biased toward features

that were more prominent on radiographs. For stifle OA,this was radiodense osteophytosis. Subchondral sclerosis inthe tibial plateau was not evaluated in our study becausethis evaluation has been shown to have a large intra- or in-

terobserver variability.14 Changes in the fabellae were alsonot included because of the assumption that these changeswere age dependent and their association with stifle OA

was questionable.2 Notch stenosis has been described as animportant feature of stifle OA7 but we did not observe this,possibly because of a younger dog age or a more acutepresentation.

Soft tissue changes were recorded separately frombony changes. Statistical evaluation showed no correlationwith clinical outcome or with other variables. Joint effu-sion/capsular thickening were usually present at surgeryand often failed to resolve. TTA, as well as TPLO, onlyprovides functional stability of the stifle joint during weightbearing, and capsular thickening is probably an attemptof the body to stabilize the joint. In addition, synovialinflammation and/or proliferation may add to theradiographically visible soft tissue silhouette. Synovialmembrane biopsies could not be taken at follow-up in ourclinical patients, so the degree of synovial inflammationduring the course of the disease remains unknown. How-

ever, lymphoplasmacellular synovitis as observed in 60.6%of the preoperative synovial membrane biopsies indicates a

chronic inflammatory process that may not resolve aftertreatment. A similar incidence of lymphoplasmacellularsynovitis (47%) has been described38 and type and degree

of synovial membrane pathology were not associated withdegree of CCL degeneration.38

The type of surgery also can have an effect on radio-graphic appearance of effusion, for example when place-ment of an intraarticular fascial graft disrupts the anatomyof the infrapatellar fat pad and the cranial femorotibialjoint space.14 The advancement of the tibial tuberosity dur-ing TTA may create more intracapsular volume, whichcould add to the radiographic signs of cranial joint effu-sion/capsular thickening. Additionally, removal of the in-frapatellar fat pad during arthroscopy decreases the size ofthe fat pad, and may also create a radiographic appearanceof joint effusion/capsular thickening.

The grade of cartilage lesion seen at surgery was the onlyfactor having an influence on progression of bony OA

changes in this study. Dogs with severe cartilage changes atsurgery seem to have a higher probability of progression ofOA as indicated by bony changes. Cartilage injury is not ev-ident on radiographs precluding prognostic information fromthe preoperative radiographs. In people, weight-bearing ra-diographs show a decrease of the joint space caused by thin-ning of the cartilage layer, but these are difficult to performand to evaluate accurately in dogs, and are not used regularlyin small animal surgery. Meniscectomy could also cause vari-ability in the width of the medial aspect of the joint space.

Much emphasis is placed on presence and degree of

osteophytosis in evaluation of the clinical status of caninejoints.5,7,9,10,16,17,36,39 Presence and progression of OA hasbeen suggested as a true test of the value of the treatment of

injured CCL,7 and thus, control of OA has been listed asone of the primary surgical goals of repair of CCL injury.9

However, achieving this goal remains elusive and many re-ports note progression of OA after stabilization despite an

acceptable clinical outcome.5,7,8,10,11,13,18,27 The value oftreatment on clinical status of patients has usually beenjudged from a lameness evaluation by a clinician or by a

client questionnaire or owners assessment at various timesafter surgery.1921,28 Force plate analysis is a more objec-tive method to evaluate limb function, and has been used inevaluation of treatment in cruciate ligament deficiencydogs.2932 The marked increase in PVF and VI at follow-up compared with preoperative values demonstrated theclinical effectiveness of TTA in our study. The comparisonof force plate with presence and progression of patterns ofnew bone formation and soft tissue changes all failed toshow significance. Thus, our results continue to support thecontention that presence or progression of OA as deter-mined on radiographs has little influence on the clinicalstatus of the joint.

Comparison of progression of OA in the stifle jointbetween studies is difficult because of differences in age,size, athletic activity, level of meniscal injury, whetherthe injury to the CCL was partial or complete or whether




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there was experimental complete section of the CCL. Thenature of the surgical or nonsurgical treatment, type of

arthrotomy,17 resulting joint stability, and experience ofthe surgeon also influence the appearance and progressionof OA in dogs with CCL disease.2 Further, placement of

dogs within groups for comparing treatment modalities hasoften not been in a random manner. Additionally, the as-

sumption that the radiographic progression of OA may notbe linear in presentation,14,15 makes comparison betweenmost clinical studies appear impossible and questions thevalue of the use of OA as a measurement of the assumedvalue of a treatment. One study suggested that progressionof OA was greater from study entry to 7 months postoper-atively than from 7 months to 13 months.14

Magnetic resonance imaging as a technique for evalu-ation of OA has the advantages of tomographic sectioningthat facilitates detection of new bone production particu-larly in the center of the joint including the femoral inter-condylar fossa, the central tibial plateau and intraaxialmargin of the femoral condyle. Cartilage thickness, joint

effusion, synovitis, subchondral sclerosis, meniscal disease,and ligament disease can be more accurately evaluated.37

Knowing that 72% of men and 67% of women with nor-mal radiographic evaluation of the knee have osteophyto-sis when examined by MR certainly highlights theincreased value of MR imaging but also questionsosteophytosis as an indicator of OA if it is found in such ahigh percentage of patients.40

Complications were encountered in 10 dogs and 5 re-quired revision surgery, which is high in comparison withother reports on TTA.20,41 Our study was conducted dur-

ing a time when implants were still under development, butthey have been improved since. The occurrence of compli-cations or the necessity of revision surgery was not associ-

ated statistically with a higher progression of OA, althougha trend (P = .08) for greater progression of OA was presentfor dogs undergoing revision surgery. A second arthros-copy or arthrotomy causes an inflammatory process in the

stifle joint and may activate degenerative joint changes.Summarily, we found that limb function characterized

by force plate analysis, improved markedly after TTA. Ev-

idence of OA characterized by bony changes progressed in55% of the treated stifles. The degree of radiographicallyvisible OA, and the progression of bone and soft tissueschanges after TTA did not correlate with functional out-come assessed by ground reaction forces. Progression ofnew bone formation was higher in dogs with severe carti-lage lesions at time of surgery, but other risk factors forprogression of stifle OA could not be determined.

REFERENCES

1. Marshall JL: Periarticular osteophytes. Initiation and

formation in the knee of the dog. Clin Orthop 1969;62:3747

2. Morgan JP: Radiology, pathology and diagnosis of

degenerative joint disease in the stifle joint of the dog. J Small

Anim Pract 1969;10:541544

3. Marshall JL, Olsson SE: Instability of the knee. J Bone Jt

Surg 1971;55A:15611570

4. Tirgari M: Changes in the canine stifle joint following rupture

of the anterior cruciate ligament. J Small Anim Pract 1977;

19:1726

5. Heffron LE, Campbell JR: Osteophyte formation in the

canine stifle joint following treatment for rupture of the

cranial cruciate ligament. J Small Anim Pract 1979;20:

603611

6. Vasseur PB, Pool RR, Arnoczky SP, et al: Correlative

biomechanical and histologic study of the cranial cruciate

ligament in dogs. Am J Vet Res 1985;46:18421854

7. Vasseur PB, Berry CR: Progression of stifle osteoarthrosis

following reconstruction of the cranial cruciate ligament in 21

dogs. J Am Anim Hosp Assoc 1992;28:129136

8. Chauvet AE, Johnson AL, Pijanowski GJ: Evaluation of

fibular head transposition, lateral fabellar suture, and

conservative treatment of cranial cruciate rupture in large

dogs: a retrospective study. J Am Anim Hosp Assoc 1996;

32:247255

9. Vasseur PB: Clinical results following nonoperativemanagement for rupture of the cranial cruciate ligament in

dogs. Vet Surg 1984;13:243246

10. Gambardella PC, Wallace LJ, Cassidy F: Lateral suture

technique for management of anterior cruciate ligament

rupture in dogs: a retrospective study. J Am Anim Hosp Assoc

1981;17:3338

11. Bennett D, Tennant B, Lewis DG, et al: A reappraisal of

anterior cruciate ligament disease in the dog. J Small Anim

Pract 1988;29:275297

12. Elkins AD, Pechman R, Kearney MT, et al: A retrospective

study evaluating the degree of degenerative joint disease in the

stifle joint of dogs following surgical repair of anterior

cruciate ligament rupture. J Am Anim Hosp Assoc 1991;27:533540

13. Geels JJ, Roush JK, Hoskinson JJ, et al: Evaluation of an

intracapsular technique for the treatment of cranial cruciate

ligament rupture. Vet Comp Orthop Traumatol2000;13:

197203

14. Innes JF, Costello M, Barr FJ, et al: Radiographic

progression of osteoarthritis of the canine stifle joint: a

prospective study. Vet Rad Ultrasound2004;45:143148

15. Lazar TP, Berry CR, deHaan JJ, et al: Long-term

radiographic comparison of tibia plateau leveling osteotomy

versus extracapsular stabilization for cranial cruciate

ligament rupture in the dog. Vet Surg 2005;34:133141

16. Rayward RM, Thomson DG, Davies JV, et al: Progression of

osteoarthritis following TPLO surgery: a prospective

radiographic study of 40 dogs. J Small Anim Prac 2004;45:

9297

17. Lineberger JA, Allen DA, Wilson ER, et al: Comparison of

radiographic arthritic changes associated with two variations

of tibia plateau leveling osteotomy. A retrospective clinical

study. Vet Comp Orthop Traumatol2005;18:1337

18. Boyd DJ, Miller CW, Etue SM, et al: Radiographic and

functional evaluation of dogs at least l year after tibia plateau

leveling osteotomy. Can Vet J2007;48:392396




8/8

19. Hurley CR, Hammer DL, Shott S: Progression of

radiographic evidence of osteoarthritis following tibial

plateau leveling osteotomy in dogs with cranial cruciate

ligament rupture: 295 cases (20012005). J Am Vet Med Assoc

2007;11:16741679

20. Hoffmann DE, Miller JM, Ober CP, et al: Tibial tuberosity

advancement in 65 canine stifles. Vet Comp Orthop Traumatol

2006;19:21922721. Innes JF, Barr ARS: Can owners assess outcome following

treatment of canine cruciate ligament deficiency? J Small

Anim Pract 1998;39:373378

22. Carey K, Aiken SW, DiResta GR, et al: Radiographic and

clinical changes of the patellar tendon after tibia plateau

leveling osteotomy. Vet Comp Orthop Traumatol2005;18:

235242

23. Mattern KL, Berry CR, Peck JN, et al: Radiographic and

ultrasonographic evaluation of the patellar ligament

following tibial plateau leveling osteotomy. Vet Radiol

Ultrasound 2006;47:185191

24. Slocum B, Slocum-Devine T: Tibia plateau leveling

osteotomy for repair of cranial cruciate ligament rupture in

the canine. Vet Clin North Am Small Anim Pract 1993;23:777795

25. Morgan JP: Radiographic diagnosis of bone and joint

diseases in the horse. Cornell Vet 1968;58(Suppl): 2846

26. Gordon WJ, Conzemius MG, Riedesel E, et al: The

relationship between limb function and radiographic

osteoarthrosis in dogs with stifle osteoarthritis. Vet Surg

2003;32:451454

27. Innes JF, Barr ARS: Clinical natural history of the

postsurgical cruciate deficient canine stifle joint: year 1.

J Small Anim Pract 1998;39:325332

28. Lafaver S, Miller NA, Stubbs WP, et al: Tibia tuberosity

advancement for stabilization of the canine cranial cruciate

ligament-deficient stifle joint: surgical technique, early results,

and complications in 101 dogs. Vet Surg 2007;36:573586

29. Budsberg SC, Verstraete MC, Soutas-Little RW, et al: Force

plate analyses before and after stabilization of canine stifles

for cruciate surgery. Am J Vet Res 1988;49:15221524

30. Jevens DJ, DeCamp CE, Hauptman J, et al: Use of force-

plate analysis of gait to compare two surgical techniques for

treatment of cranial cruciate ligament rupture in dogs. Am J

Vet Res 1996;57:389393

31. Conzemius MG, Evans RB, Besancon MF, et al: Effect of

surgical technique on limb function after surgery for rupture

of the cranial cruciate ligament in dogs. J Am Vet Med Assoc

2005;226:232236

32. Voss K, Damur DM, Guerrero T, et al: Force plate gait

analysis to assess limb function after tibial tuberosity

advancement in dogs with cranial cruciate ligament disease.

Vet Comp Orthop Traumatol2008;21:24324933. Ayral X, Altman R: Arthroscopic evaluation of knee articular

cartilage, in Brandt KD, et al: (eds): Osteoarthritis. Oxford,

Oxford University Press, 1998, pp 494505

34. Montavon PM, Damur DM, Tepic S Advancement of the

tibial tuberosity for treatment of the cranial cruciate deficient

stifle. 1st World Orthopedic Veterinary Congress, Munich,

Germany, September 58, 2002, pp 152

35. Pozzi A, Litsky AS, Field J, et al: Pressure distributions on the

medial tibial plateau after medial meniscal surgery and tibial

plateau leveling osteotomy. Vet Comp Orthop Traumatol

2008;21:814

36. Widmer WR, Buckwalter KA, Braunstein EM, et al:

Radiographic and magnetic-resonance-imaging of the stifle

joint in experimental osteoarthritis of dogs. Vet RadiolUltrasound 1994;35:371383

37. DAnjou M, Moreau M, Troncy E, et al: Osteophytosis,

subchondral bone sclerosis, joint effusion and soft tissue

thickening in canine experimental stifle osteoarthritis:

comparison between 1.5 T magnetic resonance imaging and

computed radiography. Vet Surg 2008;37:166177

38. Danielsson F, Ekman S, Andersson M: Inflammatory

response in dogs with spontaneous cranial cruciate ligament

rupture. Vet Comp Orthop Traumatol2004;17:237240

39. Park RD: Radiographic evaluation of the canine stifle joint.

Compend Contin Educ Pract Vet 1979;1:833842

40. Taouli B, Guermazi A, Lynch JA, et al: Prevalence of

meniscus and ligament tears and their correlation withcartilage morphology and other MRI features in knee

osteoarthritis (OA) in the elderly. The Health ABC study.

Arthritis Rheum 2002;46(Suppl):S148.

41. Lafaver S, Miller NA, Stubbs WP, et al: Tibial tuberosity

advancement for stabilization of the canine cranial cruciate

ligament-deficient stifle joint: surgical technique, early results,

and complications in 101 dogs. Vet Surg 2007;36:573586



correlation of radio graphic changes after tibial tuberosity

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