Custom total knee replacement in a dog with femoral condylar bone loss.

OBJECTIVE To report surgical planning, technique, and outcome of custom total knee replacement (TKR) performed to manage a medial femoral condylar nonunion in a dog. STUDY DESIGN Clinical case report. ANIMAL A 3-year-old, 20 kg Karelian Bear Hound. METHODS Computed tomographic scan of the left pelvic limb was used to build a stereolithography model of the distal portion of the femur. The model was used to create a custom augment to replace the missing medial femoral condyle and a custom stem for intramedullary condylar cemented fixation. The augment and stem were adapted to femoral and tibial components already available. The model was used to rehearse the surgery and then the custom prosthesis was implanted. RESULTS Weight bearing returned 8 hours after surgery and improved thereafter. Joint alignment was normal and prosthetic joint motion was 60-165 degrees postoperatively. The dog resumed moose hunting 3 months after surgery. Peak vertical force and impulse of the operated limb measured 17 months after surgery were 65% and 47% of the normal, contralateral limb. CONCLUSION Based on short-term follow-up, cemented canine TKR was successfully achieved for management of a severely abnormal stifle joint. CLINICAL RELEVANCE With further refinement and development of commercially available prostheses, TKR should be possible for canine patients.