Transient Osteoporosis of the Hip and Ankylosing Spondylitis: A Case Report

Transient osteoporosis of the hip (THO) is a rare, self-limiting disease of unknown etiology. THO, a primary bone marrow edema syndrome, can cause severe pain, antalgic gait, limited range of motion, and difficulty with weight bearing. Avascular necrosis, stress fractures, and infection are included in the differential diagnosis. The coexistence of THO and ankylosing spondylitis can present diagnostic challenges because the clinical presentation and various causes associated with spondyloarthropathy, such as bone marrow edema, enthesitis, early arthritis, osteonecrosis, or sterile osteomyelitis, can be attributed to the underlying cause. This case report aims to present the association of THO and spondyloarthropathy.