Stress fractures in rheumatological practice: clinical significance and localizations

The objective of this study was to analyze the clinical characteristics, associated disorders, and the most common sites of stress fractures in rheumatological patients. Over a 3-year period, 35 patients with 44 stress fractures were prospectively recruited from an outpatient rheumatological department (32 postmenopausal women and three men aged 47 to 86 years, mean 70+/-10.6 years). Clinical diagnosis was established by compatible clinical and radiological data. In addition, previous skeletal fractures were recorded in all patients. Bone mass assessment was performed in 23 patients and spinal X-ray in 21. The diagnosis of osteoporosis was defined by the presence of atraumatic vertebral fractures and/or densitometric criteria (lumbar or femoral bone mass <-2.5 T score). The most frequent stress fractures were: pelvic ring (13 sacrum and eight pubic) and metatarsal (11 fractures), followed by tibia (seven fractures), calcaneus (three fractures), femur (one), and tarsal (one). Nine patients (26%) presented simultaneous stress fractures. Twenty-four patients (69%) suffered previous osteoporotic fractures, vertebral and Colles' fractures being the most frequent. Most of the evaluated patients (25 out of 30) had osteoporosis (83%). Six patients had associated disorders (glucocorticoids use in three patients, neurologic disorders in two, and rheumatoid arthritis in one). Except for the patient with a femur fracture which required internal fixation, no other clinical complications were observed after conservative treatment. In conclusion, fractures of the pelvic ring, especially sacrum, and metatarsal are the most frequent stress fractures in rheumatological practice. The association with osteoporosis and the history of prior low-trauma fractures are common in these patients.