The treatment of osteonecrosis of the femoral head (ONFH) remains controversial. A recently proposed treatment is multiple drilling core decompression combined with systemic alendronate as a femoral head-preserving procedure for ONFH. However, it is not known whether alendronate enhances the risk of collapse. We wondered whether the combined procedure could delay or prevent progression of ONFH compared to multiple drilling alone.

Patients with early-stage ONFH were randomly assigned to be treated with either multiple drilling combined with alendronate (47 patients, 67 hips) or multiple drilling alone (46 patients, 60 hips). We defined failure as the need for THA or a Harris score less than 70. The minimum follow-up was 48months for the 77 patients completing the protocol.

After a minimum 4-year follow-up, 91% (40/44) of patients with Stage II disease and 62% (8/13) of patients with Stage III disease had not required THA in alendronate group, compared to 79% (31/39) of patients with Stage II disease and 46% (6/13) of patients with Stage III disease had not required THA in control group (P=0.12, P=0.047, respectively). Small or medium and central lesions had a better successful rate in both groups. Risk factors did not seem to affect the clinical successful rate of this procedure.

Multiple small-diameter drilling core decompression combined with systemic alendronate administration can reduce pain and delay progression of early-stage ONFH. Even in Ficat IIA and III hips, some benefit was obtained from this approach at least delay in the need for THA.