Failure after core decompression in osteonecrosis of the femoral head.

In a retrospective study of 39 hips with osteonecrosis of the femoral head treated with core decompression we evaluated the extent of the necrotic area, the Ficat stage and the location of the lesion. The extent of the necrotic lesion was classified into three categories: mild, less than 15%; moderate, 15-30%; and severe, more than 30%. In 14 mild cases core decompression failed in 2, whereas there were 4 failures out of 7 moderate cases and 16 failures out of 19 severe cases. The extent and location of the necrotic portion as well as the Ficat stage can be used as predictors for the result of core decompression in osteonecrosis of the femoral head.