Osteoid osteoma of the hip stimulating an early onset of osteoarthritis.

Thirty-six patients with osteoid osteomas in the hip were retrospectively studied, including 30 with intraarticular nidi and six with extracapsular nidi. Osteoarthritis developed in 50% of those patients with intraarticular lesions; none of the patients with extracapsular lesions had joint changes. Rheumatologic studies were conducted with eight of the patients with osteoarthritis. The cause of the degenerative joint disease is open to speculation. However, as five of the eight patients had major histocompatibility (HLA) markers for rheumatoid arthritis, the presence of this HLA factor may indicate the patients at risk for inflammatory changes in the joint.