ObjectiveTo study the clinical efficacy of core decompression and allogeneic nonvascularized fibular grafting on patients with different femoral head necrotic area. MethodsBetween January 2010 and December 2011, 59 hips in 59 patients with Ficat stage Ⅱ osteonecrosis of femoral head were treated with core decompression and allogeneic nonvascularized fibular grafting. Fifty-four patients (54 hips) were followed up. According to the necrotic area of femoral head, patients were divided into three groups: 6 hips in type A, 37 hips in type B and 11 hips in type C. We analyzed the outcomes by changes in radiographic images, Harris hip scores, hip activity and visual analogue scale (VAS) pain scores. The mean follow-up time was 40.1 months. ResultsThe postoperative X-ray images were good with no fibula prolapse, fracture or infection. Six femoral heads collapsed in patients of type C group. No head collapsed in patients grouped into type A or type B. The three groups' Harris hip scores were better than those before surgery (P<0.05). But the Harris hip score of patients with femoral head collapse was as bad as that before surgery (P>0.05). The Harris score of group C was significantly lower than group A and B (P<0.01). The joint movements of type A and type B patients were similar with those before surgery, and the VAS pain score was lower. But patients of type C suffered worse joint movement and the pain was not relieved. ConclusionThe clinical efficacy of femoral head necrotic patients treated with core decompression and allogeneic nonvascularized fibular grafting is generally good. But the risk of femoral head collapse in type C patients is high, and the clinic outcome is worse than patients of type A and B. Therefore this type of surgery is more suitable for patients with type A and B femoral head necrotic area.