Total Knee Arthroplasty Without Reduction of the Patella for Genu Valgum With Permanent Dislocation of the Patella: A Case of Nail Patella Syndrome

A 75-year-old woman presented with progressive bilateral knee pain and severe genu valgum. She could walk utilizing braces and T-canes, with a 20 degrees flexion contracture and 150 degrees of maximum flexion. During knee flexion, the patella laterally dislocated. Radiographs demonstrated severe bilateral lateral tibiofe-moral osteoarthritis and patellar dislocation. She underwent posterior-stabilized total knee arthroplasty without patellar reduction. After implantation, the knee range of motion was 0 degrees-120 degrees. Intraoperative findings revealed that the affected patella was too small, low articular cartilage volume resulted in the diagnosis of nail patella syndrome with the tetrad of nail dysplasia, patella dysplasia, elbow dysplasia, and iliac horn. At the 5-year follow-up visit, she could walk without a brace and had a knee range of motion (10 degrees-135 degrees) with clinically favorable results.(c) 2023 The Authors. Published by Elsevier Inc. on behalf of The American Association of Hip and Knee Surgeons. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).