The radiological appearance of appositional new bone on the medial part of the neck of the femur in coxarthrosis.

The X-rays of 448 hip joints with coxarthrosis (representing 304 patients) were examined. The majority (87.5%) showed appositional new bone formation on the medial part of the femoral neck in antero-posterior X-rays. Further studies showed that the extent of new bone formation on the posterior surface of the femoral neck was usually much greater than that found on the medial margin. Well trabeculated cancellous bone lay between the new bone cortex and the persisting cortex of the femoral neck. The new bone formation is considered to be a response to abnormal forces caused by limping. The radiological appearance was clearly defined into four major groups and it is suggested that the pattern observed may be related to the type of limp, the presence of a flexion deformity or anteversion of the femoral neck.