Long-term outcome of distal femoral osteotomy for treatment of combined distal femoral varus and medial patellar luxation: 12 cases (1999-2004)

Objective-To determine long-term outcome of distal femoral osteotomy as a component of treatment for distal femoral varus and medial patellar luxation in large-breed dogs. Design-Retrospective case series. Animals-12 dogs (16 stifle joints). Procedures-Medical records and radiographs were reviewed to identify large-breed dogs with medial patellar luxation (grade > 2) and femoral varus angle > 12(l treated with distal femoral osteotomy, with a minimum follow-up (by a veterinarians of 18 months. Signalment, weight, medial patellar luxation and lameness grade, pre- and postoperative femoral varus angle, surgical technique, time to radiographic bone union, and complications were recorded. Follow-up with owners via questionnaire was performed > '18 months after surgery. Results-16 corrective distal femoral osteotomies were performed with ancillary medial patellar luxation procedures in 12 dogs-, 4 dogs had staged bilateral procedures. Mean +/- SD preoperative and postoperative femoral varus angles were 16.3 +/- 4.3 degrees and 3.9 +/- 2.5 degrees, respectively. Mean SD time to radiographic union of the distal femoral osteotomy was 52.6 13 days. One dog had Kirschner wire migration from the tibial tuberosity. Patellar luxation was not detected after surgery in any dog. Mean +/- SD follow-up by a veterinarian was 1,335 410 days and by use of an owner questionnaire was 1,497 464 days. All 10 variables of 6wner-observed patient comfort and function were significantly improved. Conclusions and Clinical Relevance-Distal femoral osteotomy in combination with traditional treatment provided predictable osteotomy healing, patellar stabilization, an long-term improvement in patient comfort and function when used to treat combined-distal femoral varus and medial patellar luxation in large-breed dogs. Q Am Vet Med Assoc 2007;231:1070-1075)