CASE STUDY 3: Rapid Progressive Osteoarthritis Type 2
Rapid progressive osteoarthritis (RPOA) type 2 in an 81-year-old woman with right hip pain who was referred for right hip intra-articular corticosteroid injection.
(a) Anteroposterior right hip radiograph shows no definite osteoarthritis.
(b) Within 3 months after receiving the injection, this patient presented with worsening right hip pain. Repeat anteroposterior right hip radiograph shows subchondral insufficiency fracture, with collapse of the superior femoral head articular surface (arrows).
(c) Pain increased markedly over the following month, and this repeat anteroposterior right hip radiograph shows bone loss and destruction of the femoral head with severe joint space loss, consistent with RPOA type 2 (arrows). In addition, there are extensive cystic changes at the acetabulum (arrowheads).
Images and case study from the Radiological Society of North America; used with permission