[Occult fractures of the sacrum in aged osteoporotic patients].

We are reporting 4 cases of unnoticed sacral fractures in osteoporotic women. Their mean age was 73 years. Only in one case the fracture was seen on a standard X-Ray. On the other hand, hyperfixation with isotopes on the sacrum formed a very characteristic H-shaped image. In two of these patients, the sacral fracture was confirmed by tomodensitometry, but this examination was unavailing in the third patient. In the 4th case, hyperfixation of the isotope was not significant. Only a guided bone biopsy and the favorable evolution of the disease enabled the diagnosis of sacral fracture.