Carpometacarpal Osteoarthritis in Thirty‐Three Horses

Objective— To describe signalment, clinical, and radiographic changes associated with carpometacarpal osteoarthritis (CMC‐OA) and to report long‐term outcome. Study Design— Case series. Animals— Horses (n=33) with CMC‐OA. Methods— Medical records (1992–2007) of horses diagnosed with CMC‐OA were reviewed and signalment, clinical, and radiographic findings retrieved. Owners were contacted for information on the impact of lameness on intended use, response to treatment, progression of lameness, outcome, and owner satisfaction with response to treatment. Results— CMC‐OA identified in 39 limbs, occurred predominantly in middle‐aged and older Quarter Horses and Arabians, and caused severe lameness that prevented normal use. Characteristic swelling was centered over the 2nd metacarpal bone/2nd carpal bone articulation. Radiographic changes consisted of proliferative new bone, narrowed joint space, and subchondral lysis. Of 20 horses with follow‐up, 7 of 14 treated horses were euthanatized within 4 years and 4 of 5 nontreated horses within 3 years. Response to treatment was short lived and considered very poor by most owners. Conclusion— CMC‐OA seemingly occurs primarily in Quarter Horses and Arabians in our region. Response to conservative treatment is very poor and short‐lived with most horses being euthanatized. Clinical Relevance— Conventional treatment methods are unsuccessful for treating CMC‐OA.     

INTERMITTENT CRANIAL LUNG HERNIATION IN TWO DOGS

Two aged dogs with chronic obstructive airway disease were evaluated because of intermittent swelling of the ventral cervical region. Radiographs made at expiration and caudal positioning of the forelimbs allowed identification of intermittent cervical lung herniation of the left and right cranial lung lobe in both dogs. Pulmonary hyperinflation, increased expiratory effort, and chronic coughing were considered responsible for the lung herniation. Cervical lung hernia should be included in the differential diagnoses of intermittent cervical swelling in dogs with chronic respiratory disorders associated with increased expiratory effort and chronic coughing.     

Treatment of Carpometacarpal Osteoarthritis by Arthrodesis in 12 Horses

Objective— To evaluate arthrodesis as a treatment for carpometacarpal joint osteoarthritis (CMC‐OA). Study Design— Case series. Animals— Horses (n=12) with CMC‐OA. Methods— Arthrodesis was facilitated by insertion and fanning of a drill bit into the CMC joint at several (3–5) locations in 15 limbs. Follow‐up radiographs were obtained for 7 horses (9 limbs). Outcome was determined by telephone survey of owners based on postoperative pain, return to use, appearance of the limb, and success of treatment. Results— Postoperative pain was slight or moderate in 10 of 12 (83%) horses during the first 30 days, and 11 of 12 (92%) horses were markedly improved by 6 months and capable of returning to work. Radiographically 6 CMC joints had a bony ankylosis at follow‐up whereas 3 did not (mean 8.7 months). On long‐term follow‐up (mean 28.6 months) all horses had reduced severity of lameness, 10 of 12 (83%) were considered “sound,” 8 (67%) returned to their original activity, and all owners considered arthrodesis highly successful as a treatment. Conclusion— A drilling technique that produced CMC arthrodesis, allowed most horses to return to their original activity and was considered successful by all clients. Clinical Relevance— Arthrodesis of the CMC joint should be considered a treatment option for CMC‐OA.     

Comparison of Three Drilling Techniques for Carpometacarpal Joint Arthrodesis in Horses

Objective: To evaluate 3 drilling techniques for arthrodesis of the equine carpometacarpal (CMC) joint. Study Design: Experimental study. Sample Population: Cadaveric equine forelimbs (n=15). Methods: Limbs were divided into 3 groups (5 limbs each) to evaluate 3 drilling techniques: (1) use of a 4.5 mm drill bit inserted into the joint through 4 entry points and moved in a fanning motion; (2) a 5.5 mm drill bit inserted through 2 entry points to create 3 nonfanned drill tracts (3 drill technique); and (3) a 4.5 mm drill bit used in a 3 drill technique. The CMC joint was disarticulated after drilling, and cartilage and subchondral bone damage evaluated visually and by gross and microradiographic examination using planimetry. Results: Technique 1 produced significantly more damage of the proximal surface, but significantly less to the subchondral bone of the distal surface. Technique 1 produced the most damage to both the articular cartilage and subchondral bone of the total CMC joint than either of the 3 drill tract techniques; however, the difference between techniques 1 and 2 was not significant. Damage from technique 3 was significantly less than that with techniques 1 or 2. Conclusions: Techniques 1 and 2 produced the most cartilage and subchondral bone damage with technique 2 changes more equally distributed between proximal and distal joint surfaces. Clinical Relevance: Technique 1 (fanning) and 2 (5.5 mm 3 drill tracts) may be preferable to achieve arthrodesis of the CMC joint. Morbidity and efficacy of these arthrodesis techniques need to be evaluated in vivo.     

Fragmented Coronoid Process and Incomplete Ossification of the Humeral Condyle in a Rottweiler

Objective —To describe incomplete ossification of the humeral condyle and fragmentation of the medial coronoid process in a Rottweiler.
Study Design —Clinical report.
Animal Population —A 4-year-old sexually intact male Rottweiler.
Methods —Physical examination, radiography, and computed tomography of both elbow joints were performed initially. Drill holes were made across the humeral condyle to promote ossification. Radiography and computed tomography were repeated 14 weeks later. Radiography was repeated 15 months later. A mild, intermittent lameness remained.
Results —Preoperatively a radiolucent line was present across the right humeral condyle. This radiolucent line remained unchanged 14 weeks after drill holes were made across the condyle.
Conclusions —Incomplete ossification of the humeral condyle is present in Rottweilers.
Clinical Relevance —Incomplete ossification of the humeral condyle is present in Rottweilers and may coexist with fragmentation of the medial coronoid process in that breed. The radiographic diagnosis may be difficult because precise positioning is required to see the area of incomplete ossification. Computed tomography may be required to confirm the presence of incomplete ossification of the humeral condyle. Drilling holes across the humeral condyle does not appear to lead to union of the area of incomplete ossification.