Insufficiency fractures in patients with chronic inflammatory joint diseases.

OBJECTIVE To describe the typical sites of stress fractures in the lower extremities and pelvis in rheumatoid patients (rheumatoid arthritis, juvenile chronic arthritis, psoriatic arthritis, ankylosing spondylitis). METHODS Thirty-three patients with 52 stress fractures [mean age 44 years (range 11-73)] were studied at the authors' institution when they were being treated for their rheumatic diseases. Fourteen patients had RA, 9 JCA, 5 PsoA, and 5 SPA. Stress fractures were detected from patient documents and from series radiographs in suspected cases. In some cases magnetic resonance imaging was also performed. RESULTS One patient presented with 5 fractures, 2 patients with 4 and 3 fractures, and 7 patients with 2 fractures each. Other patients (n = 19) had only one fracture each. The metatarsal (MT) bones were the most common site of involvement. Twenty-five of the 52 fractures were located on MT I-V. The second and third most common sites were thefibula (n = 13) and tibia (n = 6). All fractures of the lower tibia or fibula were associated with valgus malalignment of the ankle. CONCLUSION If a patient with rheumatic disease experiences sudden and unexplained pain localised in the forefoot, above the ankle, below the knee, or in the pelvis, a stress fracture should be suspected. Patients with severe osteoporosis, high-load corticosteroid or methotrexate therapy, or marked joint deformity are at high risk of developing stress fracture.