Abstract
Two osteoarthritis patients had osteochondromatosis in the iliopectineal bursa which communicated with the hip joint space. They received surgical resection of the cystic mass and total hip arthroplasty and had good clinical outcomes. The authors consider that these patients' osteochondromatosis was a secondary development on the synovium of the iliopectineal bursa due to chronic inflammation caused by osteoarthritis.