ObjectiveTo investigate the effectiveness of the modified Urbaniak operation to treat avascular necrosis of the femoral head (ANFH). MethodsA retrospective analysis was made on the clinical data of 38 patients (41 hips) with ANFH treated between February 2010 and October 2012 with the modified Urbaniak operation (to add lateral femoral incision based on femoral greater trochanter incision, to preserve the original fibula flap drilling, decompression and filling through trochanteric outer cortex, and to select the descending branch of lateral circumflex femoral artery as the supply vessel). Of 38 cases, 25 were male (28 hips), 13 were female (13 hips), aged 16-52 years (mean, 34 years); there were 19 cases (21 hips) of alcoholic ANFH, 9 cases (9 hips) of traumatic ANFH, 5 cases (6 hips) of hormone ANFH, and 5 cases (5 hips) of idiopathic ANFH. The disease duration ranged from 10 months to 6 years (mean, 3.7 years). According to Ficat staging criteria, 24 hips were rated as stages II and 17 hips as stage III. The preoperative Harris hip scores were 80.63±5.02 and 77.06±6.77 in patients at stage II and III respectively. The related complications were recorded after operation. According to the findings of postoperative X-ray films, 4 grades were improvement, stabilization, deterioration, and failure; improvement or stabilization was determined to radiological success. According to the Harris score to evaluate the function of hips, more than 80 was determined to clinical success. ResultsHealing by first intention was achieved in all patients after operation. Three cases had numbness and hypoaesthesia of the lateral femoral skin, 1 case had abnormal sensation of the dorsal foot, which had no effect on daily life. Thirty-eight cases (41 hips) were followed up 1 year to 3 years and 3 months (mean, 2 years and 3 months). There was no complication such as hip joint stiffness, hip or groin persistent pain, hip joint infection, or ankle instability. At last follow-up, the X-ray films showed improvement in 23 hips (56.1%), stabilization in 17 hips (41.5%), and deterioration in 1 hip (2.4%); 40 hips obtained the radiological success. According to the Harris score, the results were excellent in 17 hips, good in 20 hips, fair in 3 hips, and poor in 1 hip with an excellent and good rate of 90.2%; 37 hips achieved the clinical success. The Harris scores were 89.92±4.12 and 86.53±5.70 in patients at stage II and III respectively at last follow-up, showing significant differences when compared with preoperative ones (t=7.011, P=0.000;t=4.412, P=0.000). ConclusionThe modified Urbaniak operation has the advantages of more convenient operation, less complications, higher safety, and better hip functional recovery. It is an effective method to treat ANFH.