Insufficiency fractures of the sacrum in elderly subjects

Elderly patients who develop insufficiency fractures of the sacrum usually have generalized bone loss and/or lesions of the pelvic bones (due to radiation therapy or previous fractures). The sacral fracture occurs either spontaneously or after a trivial traumatic episode. We compared patients admitted for sacral fractures (n = 12) or vertebral crush fractures (n = 56) in an effort to identify risk factors for sacral fractures. We conducted a retrospective review of the medical records of the 12 patients older than 70 years who were admitted to the rheumatology department of the Morvan Hospital between January 1, 1985 and December 31, 1994 for evaluation of a sacral fracture. The onset of symptoms was abrupt in 11 patients and occurred after an unremarkable fall in three. Patients admitted for sacral fractures were significantly more likely to have a positive history for a fracture, femoral surgery, or pelvic radiation therapy than patients admitted for vertebral fractures (58% versus 9%, p = 0.0005). In contrast, levels of calcium, phosphorus, 25-OH vitamin D and 1,25(OH)2 vitamin D were comparable in the two groups after exclusion of those patients with endocrine disorders or a history of calcium and vitamin D supplementation. In conclusion, populations of elderly patients with sacral fractures and crush fractures are comparable and the occurrence of a sacral fracture is dependent on the presence of pelvic and/or femoral osseous abnormalities.