Subperiosteal juxta-articular osteoid osteoma

Subperiosteal osteoid osteoma in a juxta-articular site presents a diagnostic challenge. The clinical features of joint stiffness, synovitis, muscle atrophy and local warmth may suggest arthritis rather than osteoid osteoma, while radiographs, bone scans and angiograms may not be diagnostic. We describe four cases of this rare condition.