INSUFFICIENCY FRACTURES OF THE SACRUM IN ELDERLY SUBJECTS

Elderly patients who develop insufficiency fractures of the sacrum usu ally have generalized bone loss and/or lesions of the pelvic bones (du e to radiation therapy or previous fractures). The sacral fracture occ urs either spontaneously or after a trivial traumatic episode. We comp ared patients admitted for sacral fractures (n=12) or vertebral crush fractures(n=56) in an effort to identify risk factors for sacral fract ures. We conducted a retrospective review of the medical records of th e 12 patients older than 70 years who were admitted to the rheumatolog y department of the Morvan Hospital between January 1, 1985 and Decemb er 31, 1994 for evaluation of a sacral fracture. The onset of symptoms ,vas 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 fracture s (58% versus 9%, p=0.0005). In contrast, levels of calcium, phosphoru s, 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, popu lations 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.