Total knee arthroplasty conversion for patients with ankylosed knees

Introduction: The purpose of this study was to evaluate the results of total knee arthroplasty for patients with ankylosed knees. Methods: We evaluated seven patients (10 knees) who underwent total knee arthroplasties for ankylosed knees from 1995 to 2008. There were two men and five women, with a mean age of 44.1 years (42-48 years). The mean followup period was 10.2 years (1-19.5 years). A rectus snip was performed in all cases, and V-Y quadricepsplasty was used in one case of severe quadriceps contracture. In all cases, we used the PFC Sigma PS fixed model (DePuy Orthopaedics Inc., Warsaw, Indiana, USA). The goal was more than 90° of flexion. Clinical evaluation was performed using range of motion (ROM), Knee Society (KS) Knee Score, KS Function Score, and complications. Radiographs were used to evaluate loosening or osteolysis. Results: The ROF was improved from 9.5° (0-30°) to 78.5 (15-115°), The Knee Score improved from 42.6 (25-70) to 68.6 (41-97), and the Function Score improved from 39 (0-60) to 66 (40-90). A radiolucent line was detected in two cases (one patient) around the tibial component, and one case had a necrosis of skin edge. Only one case had no improvement of motion. Conclusion: Total knee arthroplasty conversion for patients with ankylosed knees can achieve good results for motion and function without osteotomy of the tibial tuberosity when there is good quality soft tissue of the thigh.