multiple drilling combined with simvastatin versus multiple drilling alone for the treatment of avascular osteonecrosis of the femoral head 3year followup study background multiple small drilling for core decompression is widely used to preserve the femoral head in patients with avascular necrosis of the femoral head anfh nevertheless the clinical outcome remains controversial simvastatin has been demonstrated to promote bone formation and reduce bone adsorption the purpose of this study was to determine whether simvastatin enhanced the effect of multiple decompressions in preventing progression of anfh and to identify independent risk factors associated with poor resultsmethods we retrospectively analyzed 58 hips in 36 patients with a followup of 36 months 20 patients 32 hips underwent multiple drilling combined with simvastatin treatment sim group 16 patients 26 hips underwent multiple drilling alone md group we defined clinical failure as a requirement for subsequent hip surgery or harris hip score2 mm on plain radiographs was defined as radiological failureresults successful clinical results were achieved in 27 of 32 hips 84 in the sim group compared with 15 of 26 hips 58 in the md group or02 ci 01 06 p0032 successful radiological results were achieved in 27 of 32 hips 84 in the sim group and in 16 of 26 hips 615 in the md group p0048 body mass index disease stage and location of lesion were independent prognostic factors for overall survivalconclusions we believe that simvastatin could enhance the effects of multiple decompressions in preventing progression of anfh and reducing the risk of femoral head collapse