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.