Trochlear Ridge Prosthetic Replacement Surgery in 20 Dogs with Medial Patellar Luxation: Clinical and Radiographic Findings

Objective: This study aimed to describe a population of dogs that had undergone trochlear ridge prosthetic replacement with the RidgeStop surgical procedure for the correction of medial patellar luxation (MPL), and to describe clinical outcomes, owner satisfaction and radiographic changes. Study Design: Retrospective, observational review of 20 client-owned dogs. Data, including MPL and lameness grades, implant use, complications and concurrent surgical procedures, were recorded. Radiographic review was performed. A client survey gathered data on clinical signs, perceived disability and recovery time. Results: Medial patellar luxation was eliminated clinically in 24/25 limbs and radiographically in 24/25 limbs. No intraoperative complications occurred, and there was no evidence of implant movement, failure or infection. One dog with clinical and radiographic evidence of grade 4/4 MPL preoperatively subsequently experienced recurrent luxation. Owners perceived postoperative improvement in 10/14, worsening in 2/14 and no change in 2/14. Stifle effusion and osteoarthritis, particularly at the trochlear ridges and patella, were common in preoperative radiographs. Proximal patellar ligament thickening and stifle effusion were common in follow-up radiographs. Conclusion: The RidgeStop implant prevented MPL in most patients with a low complication rate. Recurrent luxation was an uncommon complication and may be associated with a higher preoperative grade. Proximal patellar ligament thickening and stifle effusion were common short-to-medium term radiographic findings.