BACKGROUND: Synovial chondromatosis (SC) is a rare disease involving cartilaginous metaplasia of synovial tissue. Treatment via synovectomy and loose body removal alone results in elevated recurrence rates, with up to 1 in 5 patients requiring conversion to a hip arthroplasty. The purpose of this study is to investigate outcomes of hip arthroplasty in the setting of SC, focusing on (1) disease-specific survival, (2) implant survivorship and complications, and (3) clinical outcomes. METHODS: We identified 26 patients with histologically confirmed SC who underwent hip arthroplasty between 1970 and 2015. Mean follow-up and patient age were 10 years (range 2-35) and 55 years (range 26-82), respectively. At the time of arthroplasty, 21 (81%) patients had "active" disease and underwent synovectomy. No constrained acetabular components were used. Six patients (23%) had a preoperative flexion contracture. RESULTS: The 15-year disease-free survival was 89%. Recurrence occurred in 3 patients at a mean of 0.8 years (range 0.03-1.2) postoperatively. Thirteen patients (50%) sustained a complication [most commonly aseptic loosening (n = 3, 12%)] and 7 required revision surgery. The 10-year and 15-year revision-free survival was 82% and 64%, respectively. Mean Harris Hip Score improved significantly from 50 (range 23-85) preoperatively to 82 (range 44-100) postoperatively (P < .001). CONCLUSION: Arthroplasty with simultaneous synovectomy provides reliable pain relief and excellent disease-specific survival at long-term follow-up; however, revision and complication rates were high.
BACKGROUND: Synovial chondromatosis (SC) is a rare disease involving cartilaginous metaplasia of synovial tissue. Treatment via synovectomy and loose body removal alone results in elevated recurrence rates, with up to 1 in 5 patients requiring conversion to a hip arthroplasty. The purpose of this study is to investigate outcomes of hip arthroplasty in the setting of SC, focusing on (1) disease-specific survival, (2) implant survivorship and complications, and (3) clinical outcomes. METHODS: We identified 26 patients with histologically confirmed SC who underwent hip arthroplasty between 1970 and 2015. Mean follow-up and patient age were 10 years (range 2-35) and 55 years (range 26-82), respectively. At the time of arthroplasty, 21 (81%) patients had "active" disease and underwent synovectomy. No constrained acetabular components were used. Six patients (23%) had a preoperative flexion contracture. RESULTS: The 15-year disease-free survival was 89%. Recurrence occurred in 3 patients at a mean of 0.8 years (range 0.03-1.2) postoperatively. Thirteen patients (50%) sustained a complication [most commonly aseptic loosening (n = 3, 12%)] and 7 required revision surgery. The 10-year and 15-year revision-free survival was 82% and 64%, respectively. Mean Harris Hip Score improved significantly from 50 (range 23-85) preoperatively to 82 (range 44-100) postoperatively (P < .001). CONCLUSION: Arthroplasty with simultaneous synovectomy provides reliable pain relief and excellent disease-specific survival at long-term follow-up; however, revision and complication rates were high.