Osteoporosis and fracture patterns. A study of split-compression fractures of the lateral tibial condyle.

The initial radiographs of 42 split-compression fractures of the lateral tibial condyle were studied. The breadth of the wedge-shaped fragments, measured at the level of the articular surface, was found to decrease with increasing severity of osteoporosis. Ranks were assigned to the breadths and average ranks to the grades (low ranks for normals). Spearman's rank correlation co-efficient was -0.507, which is significant at the 1% level. The length of the fragments showed a similar decrease with advancing bone loss. Rank correlation with the degree of osteoporosis was -0.393, which is significant at the 5% level. These results support the hypothesis that the fracture pattern depends on the changes in bony architecture which results from osteoporosis.