To evaluate the effectiveness of core decompression with impaction bone graft in regard to the stage of the disease.

Forty-two cases in 32 patients were classified using ARCO (Association Research Circulation Osseous, 1992) classification and twenty-five cases were compared with postoperative follow-up MRI evaluation. There were 26 male and 6 female patients. Ten patients among 32 were bilatellally involved.

There were 9 hips of stage 1 (A,O; B,1; C,8), 29 hips of stage 2 (A,1; B,6; C,22) and 4 hips of stage 3 (only C). Radiological progression was seen in 21 of 42 hips (50%); 22% of stage 1 (2/9), 59% of stage 2 (16/29) and 75% of stage 3 (3/4). Clinical failure with total hip arthroplasty conversion was seen in 11 of 42 hips (26%); 28% of stage 2 (8/29) and 75% of 3 (3/4). Forty-three percents of lateral lesions (11/26 cases) and all cases with femoral head involvement more than 30% showed clinical failure and radiologic progression.

When the outcome of core decompression with impaction bone graft was evaluated according to ARCO classification, the progression of the stage or conversion to total hip arthroplasty was more common in the larger lesion and lateral location of necrosis. So, we could predict that core decompression with impaction bone graft was ineffective in preventing the progression of disease in the case of large extent and/or lateral location of necrosis.