Total Hip Arthroplasty for Giant Hip Synovial Chondromatosis With Acetabular Involvement Complicated by Osteoarthritis: A 12-Year Follow-Up of a Case and Literature Review.

Synovial chondromatosis (SC) is a rare benign synovial disorder. Giant hip SC with acetabular involvement in the setting of end-stage osteoarthritis remains exceptionally uncommon, with limited long-term evidence available. We report a 50-year-old woman with giant SC of the left hip and acetabular invasion (Kellgren-Lawrence grade IV osteoarthritis), treated with cementless total hip arthroplasty via the Moore posterior approach combined with lesion resection and synovectomy. At 12-year follow-up, the patient achieved a Harris Hip Score of 98, with complete pain relief, stable prosthesis fixation, and no recurrence or malignant transformation. In addition, a literature review of 203 reported hip SC cases (2018-2024) demonstrated recurrence and revision rates of 10.34% and 22.58%, respectively, following total hip arthroplasty. No previously reported cases described giant SC with acetabular involvement.