The Effect of Partial Rostral Hemimandibulectomy on Mandibular Mobility and Temporomandibular Joint Morphology in the Dog

Partial rostral hemimandibulectomy was performed in 10 adult dogs. The temporomandibular joints (TMJs) were examined radiographically and tomographically before surgery, and mandibular stability was evaluated before and immediately after surgery. Radiographic, tomographic, and hemimandibular mobility assessments were made again at months 3 and 6. The TMJs were examined grossly and histologically in five dogs euthanatized at month 3 and in five dogs euthanatized at month 6. Statistically significant hemimandibular instability (p less than 0.05) persisted in all subjects throughout the study. The radiographic appearance of the joints remained unaltered; however, space asymmetry was identified in postoperative tomograms of three dogs at month 3 and four dogs at month 6. The TMJs were grossly normal at necropsy. Histologically, there were degenerative changes in articular cartilage and subchondral bone in all of the joints. The authors conclude that partial rostral hemimandibulectomy causes TMJ degeneration, as a consequence of hemimandibular instability or abnormal loading, or both.     

RADIOGRAPHIC EVALUATION OF FELINE APPENDICULAR DEGENERATIVE JOINT DISEASE VS. MACROSCOPIC APPEARANCE OF ARTICULAR CARTILAGE

Degenerative joint disease (DJD) is common in domesticated cats. Our purpose was to describe how radiographic findings thought to indicate feline DJD relate to macroscopic cartilage degeneration in appendicular joints. Thirty adult cats euthanized for reasons unrelated to this study were evaluated. Orthogonal digital radiographs of the elbow, tarsus, stifle, and coxofemoral joints were evaluated for the presence of DJD. The same joints were dissected for visual inspection of changes indicative of DJD and macroscopic cartilage damage was graded using a Total Cartilage Damage Score. When considering all joints, there was statistically significant fair correlation between cartilage damage and the presence of osteophytes and joint‐associated mineralizations, and the subjective radiographic DJD score. Most correlations were statistically significant when looking at the different joints individually, but only the correlation between the presence of osteophytes and the subjective radiographic DJD score with the presence of cartilage damage in the elbow and coxofemoral joints had a value above 0.4 (moderate correlation). The joints most likely to have cartilage damage without radiographic evidence of DJD are the stifle (71% of radiographically normal joints) followed by the coxofemoral joint (57%), elbow (57%), and tarsal joint (46%). Our data support radiographic findings not relating well to cartilage degeneration, and that other modalities should be evaluated to aid in making a diagnosis of feline DJD.     

The pathogenesis of canine hip dysplasia.

Dogs with CHD are born with normal hips that subsequently undergo varying degrees of subluxation of the coxofemoral joint. Although the etiology of CHD is multifactorial, the pathogenesis or stages of change within the affected coxofemoral joint(s) are similar regardless of cause. With the onset of the disease, there are progressive structural changes including joint laxity and femoral head subluxation; swelling, stretching, fraying, and eventual rupture of the teres ligament; a shallow, flattened acetabulum, deformity of the head; erosion of articular cartilage, eburnation of subchondral bone, DJD; and periarticular osteophyte formation.     

Brachygnathia superior and degenerative joint disease: a new lethal syndrome in Angus calves

Brachygnathia superior and generalized diarthrodial degenerative joint disease were seen in 17 related, purebred Angus calves ranging in age from 2 days to 4 months. Craniometrical studies revealed decreased maxillary and palatine bone lengths and increased cranial, skull, and facial indices. Radiological evaluation of major appendicular joints demonstrated lipping of the joint margins with osteophyte formation, sclerosis of subchondral bone, and narrowing of joint spaces. Synovial fluid evaluation indicated joint degeneration but no etiologic agent. Rheumatoid factor analysis of plasma was negative. Grossly, all major appendicular joints were defective including the atlanto-occipital articulation. Lesions ranged from loss of surface luster to erosions and deep ulcers with eburnation of the subchondral bone and secondary proliferative synovitis. Histological changes were degeneration of the articular cartilage matrix, chondrocyte necrosis, flaking and fibrillation, chondrone formation, erosions and ulcers of the articular cartilage with subchondral bone sclerosis, vascular invasion with fibrosis, and chronic, nonsuppurative, proliferative synovitis. Growth plates had defective chondrocyte proliferation and hypertrophy with aberrant ossification of calcified cartilaginous matrix. Histochemical analysis of cartilage and bone failed to incriminate which component was defective, glycosaminoglycan or collagen, but indicated different distribution or absence of one or the other. Genealogic studies revealed a genetic basis for the new defect.     

COMPARISON OF THE ULTRASONOGRAPHIC APPEARANCE OF OSTEOCHONDROSIS LESIONS IN THE CANINE SHOULDER WITH RADIOGRAPHY, ARTHROGRAPHY, AND ARTHROSCOPY

Osteochondrosis lesions in 29 shoulder joints (from 20 dogs) were evaluated with ultrasound (US) and the results were compared with survey radiography, arthrography, and arthroscopy. US was performed with a 7-12 MHz linear matrix transducer which was placed in cranio-caudal direction just distally to the acromion while the joint was adducted and maximally endorotated to visualize the caudal aspect of the humeral head. With US, the subchondral defect was completely visible in 21 joints and partially visible in 8 joints. The length of the subchondral defect measured on US was comparable with the length measured on survey radiographs. In two joints, the cartilage flap was mineralized and thus already visible on survey radiographs. The mineralized flap was visible on US as a straight hyperechoic line above the subchondral defect. In the other joints, survey radiographs could not assess the status of the articular cartilage. In 17 joints, the presence of a cartilage flap or cartilage fissuring was suspected based on the presence of a second hyperechoic line at the base of the subchondral defect, and this suspicion was confirmed by arthroscopic examination in 16 joints and also by arthrographic examination in 15 joints. One joint that was suspected of having a cartilage flap on US was normal on arthroscopy and arthrography. When US revealed only focal thickening of the anechoic cartilage layer (5 joints), the joints appeared normal on arthroscopic and arthrographic examination. Of the four joints where the subchondral defect was irregular and covered by heteroechogeneous material on US, arthroseopy revealed the presence of a lesion resembling chondromalacia in two joints, the presence of a small cartilage flap in one joint and the presence of scar tissue underneath the flap at the level of the subchondral defect in one joint. In conclusion, US is a helpful imaging modality in the identification of osteochondritic lesions in the canine shoulder joint. US also appears to be a satisfactory imaging tool for identifying lesions such as joint mice, joint effusion, and distinct new bone formation.     

Spectrum of computed tomographic findings in 58 canine elbows with fragmentation of the medial coronoid process

O bjective : To describe in detail the computed tomographic findings in elbows of dogs with fragmentation of the medial coronoid process of the ulna.
M ethods : Retrospective review of computed tomographic images of 58 elbows that had displaced medial coronoid process fragment(s), non-displaced medial coronoid process fragment or a stable fissure in the articular cartilage of the medial coronoid process at arthroscopy.
R esults : Bone fragments were observed in 85 per cent elbows with a displaced fragment at arthroscopy, in 18 per cent elbows with a non-displaced fragment and in 29 per cent elbows with a stable fissure. Fissures in the subchondral bone were observed in computed tomographic images of 43 per cent elbows that had a stable fissure at arthroscopy. Abnormal shape, sclerosis and lucency affecting the medial coronoid process, subchondral sclerosis of the ulna and humerus, irregular radial incisure of the ulna and periarticular osteophytes were observed in a similar proportion in dogs regardless of the arthroscopic findings. Kissing lesions affecting the medial aspect of the humeral condyle were mainly associated with displaced fragments. Signs of joint incongruity were observed in dorsal and sagittal reconstructed computed tomographic images in 24 per cent elbows.
C linical S ignificance : A wide range of abnormalities may be observed in computed tomographic images of dogs with fragmented medial coronoid process. Computed tomographic is moderately sensitive for detection of fragments.     

A phalangeal fusion defect and osteochondrosis dissecans with subluxation of the distal interphalangeal joints in a foal

A fusion defect of the proximal and middle phalanges of both hindlimbs, osteochondrosis dissecans of the distal interphalangeal joints of the forelimbs, and subluxation of all 4 distal interphalangeal joints occurred in a Standardbred filly. Lameness was the first abnormality noted and was observed at one week of age in the left forelimb and progressed until all 4 limbs were affected by 5 weeks of age. On radiographs of both forelimbs, the distal interphalangeal joints were subluxated with irregularity and lucency of subchondral bone. On radiographs of the distal hindlimbs, there was a subluxation of both distal interphalangeal joints and loss of the proximal interphalangeal joint spaces with fusion of the proximal and middle phalanges. The foal was euthanised. On necropsy, there were focal areas of erosion of articular cartilage in the distal interphalangeal joint of both forelimbs. The proximal and middle phalanges of both hindlimbs were fused. Histopathological examination of the distal interphalangeal joint of the right foreleg showed loss of articular cartilage and degenerative changes in the exposed subchondral bone.     

Clinical evaluation of dogs after surgical and nonsurgical management of osteochondritis dissecans of the talus

Osteochondritis dissecans of the medial aspect of the talus was diagnosed in 17 joints in 11 dogs. In 10 of the 11 dogs, intermittent lameness had persisted after initial diagnosis and therapy. Radiographs made during the initial examination showed a widening of the medial tarsocrural joint space, with osteophyte formation involving the medial and caudal tarsocrural joint. The follow-up radiographs showed greatest change in the increase in reactive bone formation, especially involving the medial and caudal aspects of the tarsocrural joint and the medial aspect of the talus. Arthrotomy for flap removal and curettage was performed on 11 joints; 6 joints did not receive surgery. After a mean period of 34 months following diagnosis, the dogs were examined clinically and the affected joints were radiographed. The degree of lameness, range of motion, and stability of the tarsocrural joint were graded for each limb. Radiographic determinants that were assessed included: width of the medial tarsocrural joint space, medial tarsocrural osteophyte formation, lateral tarsocrural osteophyte formation, caudal tarsocrural osteophyte formation, medial talus osteophyte formation, lateral talus osteophyte formation, intertarsal osteophyte formation, subchondral sclerosis of the distal end of the tibia, presence of joint bodies, and periarticular soft-tissue thickness. On the basis of clinical and radiographic evaluations, the surgical procedures described in this report did not modify progression of osteoarthritic changes.     

Radiographic assessment of the progression of osteoarthrosis in the contralateral stifle joint of dogs with a ruptured cranial cruciate ligament

The formation and progression of osteoarthrosis in the unaffected contralateral stifle joints of 14 dogs with a unilateral cranial cruciate ligament rupture were monitored radiographically in terms of a global score and the scores for 10 parameters specific for the stifle joint. The dogs were examined initially and six and 12 months later by three observers, and the variability between the observers' scores was also assessed. The score for osteophytes at the tibial attachment site of the ligament was the most reliable parameter, and that for the increase in femoropatellar joint space was the least reliable. In the contralateral stifle joints there were significant increases after six and 12 months in osteophyte formation caudal to the tibial plateau, and in subchondral sclerosis of the tibial plateau and of the long digital extensor muscle groove. These three parameters progressed more regularly during the disease process than the other parameters. The global osteoarthrosis score of the contralateral stifle joint was an important risk factor for sustaining a rupture of the cranial cruciate ligament in that joint during the next six months.     

COMPARISON OF RADIOGRAPHIC SUBCHONDRAL BONE CHANGES WITH ARTHROSCOPIC FINDINGS IN THE EQUINE FEMOROPATELLAR AND FEMOROTIBIAL JOINTS: A RETROSPECTIVE STUDY OF 72 JOINTS (50 HORSES)

Radiographs of 72 femoropatellar and femorotibial joints from 50 horses were evaluated. Ninety four arthroscopically evaluated areas were graded according to a predetermined system. The radiographic grade was then compared to arthroscopic findings in the same location. Statistical analysis was performed to determine the association between the radiographic subchondral bone changes and arthroscopic findings. Radiographically normal areas in the femoropatellar joint were arthroscopically positive for cartilaginous changes in 40% of the femoropatellar joints. Areas of mild subchondral bone flattening (grade I) in the lateral trochlear ridge were arthroscopically positive for cartilage changes 78% of the time. Ninety six percent of moderate to severe subchondral bone changes (grades II-V) were arthroscopically positive for cartilage damage. This research demonstrates that (1) a significant number of radiographically normal joints will have cartilage changes, (2) areas of mild subchondral bone flattening have cartilage changes present in the majority of cases and (3) areas of moderate to severe subchondral bone changes have arthroscopically detectable cartilage changes present.     

Pulsed Carbon Dioxide Laser for Cartilage Vaporization and Subchondral Bone Perforation in Horses Part I: Technique and Clinical Results

A carbon dioxide laser, used in a rapidly pulsed mode, was evaluated for intra-articular use in horses. Under arthroscopic guidance, a lensed 5 mm laser probe attached directly to a hand-held carbon dioxide laser was inserted into one intercarpal joint of eight horses. In four horses, a cartilage crater 1 cm in diameter was created to the level of the subchondral bone of the articular surface of the third carpal bone. In four horses, the laser was directed perpendicular to the articular surface of the third carpal bone and activated to penetrate the cartilage and subchondral bone. The intercarpal joint of the opposite carpus in each horse was subjected to arthroscopic examination and insertion of the laser probe for an equivalent time. The laser was not activated and these joints served as sham operated controls. The horses were evaluated clinically for 8 weeks, then euthanatized, and the joints were examined radiographically, grossly, and histologically. Pulsed carbon dioxide laser vaporized cartilage readily but penetrated bone poorly. Cartilage vaporization resulted in no greater swelling, heat, pain on flexion, lameness, or synovial fluid reaction than the sham procedure. Laser drilling resulted in a shallow, charred hole with a tenacious carbon residue, and in combination with the thermal damage to deeper bone, resulted in increased swelling, mild lameness and a low-grade, but persistent synovitis. The carbon dioxide laser is a useful intra-articular instrument for removal of cartilage and has potential application in inaccessible regions of diarthrodial joints. It does not penetrate bone sufficiently to have application in subchondral drilling.     

Pulsed Carbon Dioxide Laser for Cartilage Vaporization and Subchondral Bone Perforation in Horses Part II: Morphologic and Histochemical Reactions

A pulsed carbon dioxide laser was used to vaporize articular cartilage in four horses, and perforate the cartilage and subchondral bone in four horses. Both intercarpal joints were examined arthroscopically and either a 1 cm cartilage crater or a series of holes was created in the third carpal bone of one joint. The contralateral carpus served as a control. After euthanasia at week 8, the treated and control joints were examined for gross changes, and samples of cartilage and subchondral bone, synovial membrane, and peripheral lymph nodes were examined histologically. Depletion of cartilage matrix glycosaminoglycan was assessed by safranin-O histochemical staining of the laser site and adjacent cartilage. Cartilage removal by laser vaporization resulted in rapid regrowth, with fibrous and fibrovascular tissue and occasional regions of fibrocartilage at week 8. The subchondral bone, synovial membrane, and draining lymph nodes appeared essentially unaffected by the laser cartilage vaporization procedure. Conversely, carbon dioxide laser drilling of subchondral bone resulted in poor penetration, extensive areas of thermal necrosis of bone, and significant secondary damage to the apposing articular surface of the radial carpal bone.     

Assessment of bone mineral density of the femoral head in dogs with early osteoarthritis

OBJECTIVE: To compare the bone mineral density (BMD) of the proximal portion of the femur in dogs with and without early osteoarthritis secondary to hip dysplasia. ANIMALS: 24 dogs (3 Greyhounds, 6 Labrador-Greyhound crossbreeds, and 15 Labrador Retrievers). PROCEDURE: Computed tomography (CT) of the pelvis, including a bone-density phantom, was performed for each dog. Centrally located transverse CT slices and a computer workstation were used to identify 16 regions of interest (ROIs) in the proximal portion of the femur. For each ROI, the mean Hounsfield unit value was recorded; by use of the bone-density phantom and linear regression analysis, those values were converted to equivalent BMD (eBMD). Mean eBMD values for the subchondral and nonsubchondral ROIs in dogs with and without osteoarthritis (determined at necropsy) were compared. A mixed-model ANOVA and post hoc linear contrasts were used to evaluate the effects of osteoarthritis, breed, and sex on the BMD value. RESULTS: At necropsy, osteoarthritis was detected in 14 hip joints in 9 dogs; all lesions included early cartilage fibrillation. After adjusting for breed and sex, eBMD in subchondral ROIs 8 and 12 (adjacent to the fovea) were 8% and 6% higher, respectively, in osteoarthritis-affected dogs, compared with unaffected dogs; in the nonsubchondral ROIs, eBMD was 10% higher in osteoarthritis-affected dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with findings in unaffected dogs, increased eBMD in hip joints of dogs with early osteoarthritis supports a strong relationship between the subchondral and epiphyseal regions and articular cartilage in the pathogenesis and progression of osteoarthritis.     

Distribution of beta-endorphin and substance P in the shoulder joint of the dog before and after a low impact exercise programme

Beta-endorphin and substance P were immunolocalized in the articular cartilage, synovial membrane and fibrous joint capsule of dogs. Twelve adult greyhounds were randomly assigned to one of three groups: control, limited exercise, or regimented exercise. On day 0, biopsies of articular cartilage and joint capsule were obtained from the left shoulder joints of dogs receiving limited and regimented exercise. On day 72, biopsies of joint capsule from right and left shoulders and articular cartilage from the right shoulder joint were analysed for the presence of glycosaminoglycans (GAG) and for immunolocalization of substance P and beta-endorphin. Regimented exercise increased the presence of GAGs and immunolocalization of substance P and beta-endorphin in articular cartilage and synovial membrane compared to day 0 biopsies and untreated controls. Localization of beta-endorphin became prominent in and around the chondrocytes. Substance P was increased in chondrocytes and extracellular matrix. Concomitant changes in localization of beta-endorphin and substance P may have a role in the modulation of the microphysiological environment, metabolism, or function of joint tissues in response to low-impact exercise.     

Feline chronic progressive polyarthritis

Twenty cats with a chronic progressive polyarthritis were studied. The disorder occurred exclusively in male cats, and all but six of the cats were between 1.5 and 5.0 years of age. There were two forms of the disease as determined by radiographic changes: joint instability and deformity, and clinical course. The most prevalent form of the disease was characterized by osteopenia and periosteal new bone formation surrounding affected joints. Marginal periarticular erosions and collapse of the joint spaces with fibrous ankylosis occurred with time, but joint instability and deformities were not seen. The second form of the disease was characterized by severe subchondral marginal erosions, joint instability, and deformities. The periosteal proliferative form resembled Reiter's arthritis of man, and the deforming type resembled human rheumatoid arthritis. The disease began as tenosynovitis and synovitis, with subsequent changes in the articular cartilage and periosteal bone. Histopathologic changes in these cats were similar to those occurring in both chronic Reiter's and rheumatoid arthritis of man. Chronic progressive polyarthritis of cats was not caused by identifiable bacteria or mycoplasma, but was etiologically linked to feline leukemia virus (FeLV) and feline syncytia-forming virus (FeSFV) infections. The FeSFV was isolated from the blood or was detected by a serologic test in all of the cats with the disease, whereas FeLV was isolated or identified by immunofluorescence technique in 60% of the cats. The arthritis could not be reproduced by inoculation of cell-free cynovial tissue from diseased cats or with tissue culture fluid containing FeSFV and FeLV isolates. It was postulated that arthritis was an uncommon manifestation of FeSFV infection that occurred in predisposed male cats. Feline leukemia virus may not have been directly involved in the disease, but may have acted in some way to potentiate the pathogenic effects of FeSFV.     

Functional, radiographic, and histologic assessment of healing of autogenous osteochondral grafts and full-thickness cartilage defects in the talus of dogs.

A circular (5.5 mm diameter) full-thickness cartilage defect was created on the medial ridge of the talus in 12 skeletally mature dogs. In 6 dogs, the articular surface of the lesion was repaired, using an osteochondral graft obtained from the ipsilateral manus. The graft (digit I, first phalanx, distal articular surface and diaphysis) was contoured to obtain a press fit in the drilled talar recipient site. In 6 dogs, the lesion was not treated and healed by fibrous tissue replacement. Functional assessment (lameness, hock range of motion, joint stability, joint crepitus, and mid-femoral muscle circumference) was completed before surgery and at postoperative weeks 2 through 20. Radiographic assessment (periarticular soft tissue width, joint space width, osteophyte formation, and graft incorporation) was completed before surgery and at postoperative weeks 0, 6, 12, and 20. To facilitate histologic assessment, tissues were stained with toluidine blue and H&E. Histologic assessment of the articular surface on the surgically treated talus, ipsilateral tibia, and contralateral talus was completed, using a modification of the Mankin grading system. Subchondral bone was examined to assess graft viability and incorporation. Analysis of the ordinal data was completed, using a Mann-Whitney rank sum test. All dogs were fully weight bearing by postoperative week 7. Dogs without grafts had significantly (P = 0.036) better clinical function at postoperative week 6. Significant difference in functional assessment was not evident at postoperative week 20. Immediate postoperative radiographic assessment revealed significant (P = 0.005) difference between nongrafted and grafted groups. Significant difference was not observed at postoperative week 6, 12, or 20. All grafts appeared radiographically incorporated by postoperative week 12. All grafts restored joint surface congruity, whereas 3 of 6 nongrafted lesions had poor articular congruity. Of 6 grafts, 4 partially retained normal hyaline cartilage, resulting in significantly (P = 0.014) lower Mankin grades. Significant histologic differences between groups were not apparent when the apposing tibia and control talus were examined. Talar reconstruction by use of a phalangeal osteochondral graft is a viable surgical procedure. These data indicate that normal articular and subchondral architecture are more closely approximated by osteochondral reconstruction than by fibrous tissue repair.     

Diagnostic findings and prognosis following arthroscopic treatment of subtle osteochondral lesions in the shoulder joint of horses: 15 cases (1996-1999)

OBJECTIVE: To determine clinical, scintigraphic, radiographic, and arthroscopic findings and results of treatment in horses with lameness attributable to subtle osteochondral lesions of the shoulder joint. DESIGN: Retrospective study. ANIMALS: 15 horses. PROCEDURE: Medical records were reviewed, and results of physical examination, scintigraphy, radiography, arthroscopy, and treatment were recorded. RESULTS: Severity of lameness ranged from grade 1 to 4. Response to shoulder flexion or extension was variable. Twelve horses had a narrow upright foot. Intra-articular anesthesia of the shoulder joint localized the cause of the lameness to the shoulder joint in 9 of 10 horses. Scintigraphic abnormalities were detected in 4 of 6 horses. Radiographic lesions were subtle and included glenoid sclerosis, focal glenoid lysis, small glenoid cysts, and alterations in the humeral head contour. Arthroscopic evaluation confirmed clefts in the glenoid cartilage, glenoid cysts, a humeral head cyst, fibrillation of the humeral head cartilage, cartilage fragmentation, or a nondisplaced fracture of the humeral head. After treatment, 12 horses returned to their previous level of performance, 1 was sound for light riding, 1 remained lame, and 1 was euthanatized because of chronic lameness. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a combination of physical examination, scintigraphy, and radiography is necessary to diagnose subtle osteochondral lesions of the shoulder joint in horses. Arthroscopy can be used to confirm the diagnosis and treat cartilage and subchondral bone lesions. Young and middle-aged horses with subtle osteochondral lesions of the shoulder joints have a good prognosis for return to performance following arthroscopic treatment.     

Scapulohumeral osteoarthritis in 20 Shetland ponies, miniature horses and falabella ponies

This paper describes the clinical and diagnostic features of 20 cases of scapulohumeral osteoarthritis in Shetland ponies, miniature horses and falabella ponies. The history and clinical signs were similar in all the cases Radiographically they all had consistent changes which consisted predominantly of articular osteophytes and periarticular enthesiophytes. Six of the cases had radiographic evidence of dysplasia of the scapulohumeral joint, although it was uncertain whether this was a primary or a secondary finding. No specific treatment appeared to be advantageous. At follow up, six of the ponies had to be euthanased owing to continuing severe lameness; the other 14 ponies remained lame, but were maintained at pasture by the occasional use of oral non-steroidal anti-inflammatory drugs. No definitive aetiology for the condition was identified, but it is proposed that an underlying dysplasia, or lack of collateral support may predispose the scapulohumeral joint of miniature horse breeds to the disease.     

Evaluation of the prognostic value of positive-contrast shoulder arthrography for bilateral osteochondrosis lesions in dogs

To investigate whether arthrographic findings had any prognostic value with respect to treatment and outcome of bilateral osteochondrosis, shoulder arthrograms (n = 80) from 40 dogs with bilateral lesions were evaluated. Arthrography was performed, using 1.5 to 4 ml of a 25% solution of meglumine-sodium diatrizoate, with admixture of 0.2 mg of epinephrine. A shoulder with signs of pain and lameness was surgically treated. The contralateral shoulder was treated conservatively, and the final outcome was compared with the arthrographic findings. In 37 dogs, signs of lameness and pain were associated with a loose cartilage flap and, in 3, with a detached cartilage flap. In 2 dogs, admitted with bilateral lameness, a loose cartilage flap was detected in both shoulders. Of 12 dogs with a detectable loose cartilage flap in the contralateral shoulder joint, 6 became lame 2 to 4 months after initial surgical intervention and needed bilateral surgery. In the contralateral joint, development of thick articular cartilage over the subchondral defect or a detached cartilage flap lodged in the caudal pouch of the shoulder joint was a favorable prognostic sign. Such dogs had no signs of lameness on the contralateral side during a follow-up period that ranged from 1 to 7 years.     

Comparison of the effects of caudal pole hemi-meniscectomy and complete medial meniscectomy in the canine stifle joint

OBJECTIVE: To compare the effects of caudal pole hemi-meniscectomy (CPHM) and complete medial meniscectomy (MM), specifically with respect to development of secondary osteoarthritis, in the stifle joints of clinically normal dogs. ANIMALS: 14 large-breed dogs. PROCEDURE: Unilateral CPHM (7 dogs) or MM (7) was performed, and the left stifle joints served as untreated control joints. Gait was assessed in all dogs before surgery and at 4, 8, 12, and 16 weeks postoperatively. After euthanasia, joints were evaluated grossly; Mankin cartilage scores, subchondral bone density assessment, and articular cartilage proteoglycan extraction and western blot analyses of 3B3(-) and 7D4 epitopes were performed. RESULTS: Weight distribution on control limbs exceeded that of treated limbs at 4 and 16 weeks after surgery in the CPHM group and at 4 and 8 weeks after surgery in the MM group; weight distribution was not significantly different between the 2 groups. After 16 weeks, incomplete meniscal regeneration and cartilage fibrillation on the medial aspect of the tibial plateau and medial femoral condyle were detected in treated joints in both groups. Mankin cartilage scores, subchondral bone density, and immunoexpression of 3B3(-) or 7D4 in articular cartilage in CPHM- or MM-treated joints were similar; 7D4 epitope concentration in synovial fluid was significantly greater in the MM-treated joints than in CPHM-treated joints. CONCLUSIONS AND CLINICAL RELEVANCE: Overall severity of secondary osteoarthritis induced by CPHM and MM was similar. Investigation of 7D4 epitope concentration in synovial fluid suggested that CPHM was associated with less disruption of chondrocyte metabolism.