This study followed the clinical outcome of 6 dogs with severe end-stage osteoarthritis that underwent total knee replacement (TKR). This procedure is more traditional in human medicine, and TKR surgery in dogs has been used only for the past few decades. No reports describe the technique or clinical results of TKR in dogs with severe osteoarthritis of the stifle joint, but a successful TKR in a dog with femoral condyle bone loss has been reported.

Dogs were included in the study if (1) their owners had observed lameness, (2) they had less than 80% ground-reaction forces in the contralateral limb, and (3) their prognosis for successful outcome after reconstructive surgery, based on the opinion of 3 board-certified veterinary surgeons, was so poor that arthrodesis or amputation was the only other surgical option. Three dogs had previously undergone surgery (repair of anterior cruciate ligament, repair of medial patellar luxation, and osteochondral autogenous transfer for osteochondritis dissecans of the lateral femoral condyle on the affected stifle).

The authors describe the surgical technique in detail. Five dogs had a cemented prosthesis and 1 dog had a cementless tibial prosthesis. Radiographs taken 1 year after surgery did not show evidence of bone-cement or implant loosening. Two dogs could not bear weight consistently before surgery and therefore did not have presurgical force-plate analyses; however, postoperative force-plate measurements in all dogs showed steady improvement on the affected limbs. Of note, 1 dog with contralateral osteoarthritis had an improved impulse reading on the TKR side compared with the contralateral side after surgery. Overall, stifle extension and excursion angles were significantly improved 3 months after surgery and mean peak vertical force and impulse were significantly improved by 6 months. The authors conclude that TKR is an option when treating dogs with severe nonseptic stifle osteoarthritis.

COMMENTARY: These exciting data suggest that even dogs with non–weight-bearing osteoarthritis can benefit from TKR. Future studies should include more objective data on functional improvement in dogs with different levels of severity of osteoarthritis and determine whether an improved quality of life beyond a year can be expected with surgery. It will be a welcome development when the technique becomes both affordable and widely available for referring general practitioners.

Canine total knee replacement: Surgical technique and one-year outcome. Liska WD, Doyle ND. VET SURG 38: 568-582, 2009.