Objective To investigate the procedure and effectiveness of medial patellofemoral l igament (MPFL) reconstruction for the treatment of recurrent patellar dislocation. Methods Between June 2005 and September 2007, 29 patients with recurrent patellar dislocation underwent MPFL reconstruction with allograft semitendinosus or allograft anterior tibial is tendon. There were 6 males and 23 females with an average age of 20.3 years (range, 13-45 years). The patients sufferedfrom 2-10 times patellar dislocation preoperatively. The average time between last dislocation and surgery was 43.9 months (range, 1-144 months). CT scan was performed to measure the tibial tuberosity-trochlear groove distance (TT-TG). The femoral tunnel was made at the origin of MPFL insertion, just inferior to the medial epicondyle. The double L-shape patellar tunnels were made on the medial rim of patella with 4.5 mm in diameter. The loop side of the graft was fixed with a bioabsorbable interference screw in the femoral tunnel both ends of the graft. For the TT-TG was more than 20 mm, a modified Elmsl ie-Trillat osteotomy was performed to correct the distal al ignment of patella. The arthroscopic examination was also performed for loosebody and lateral retinacular release. Results Twenty-seven patients were followed up 45.5 months on average (range, 40-67 months). No recurrent dislocation or subdislocation occurred. All the patients showed negative apprehension test at 0° and 30° flexions of knee. The range of motion of knee restored normal 1 year after operation. The Kujala score was improved from 72.03 ± 17.38 preoperatively to 94.10 ± 7.59 postoperatively, and Lysholm score was improved from 72.65 ± 14.70 to 95.44 ± 6.25, both showing significant differences (P lt; 0.05). The Tegner score was decreased from 5.25 ± 1.83 preoperatively to 4.33 ± 1.00 postoperatively, showing no significant difference (t=1.302, P=0.213). In patients whose TT-TG was more than 20 mm, TTTG was decreased from (23.38 ± 3.70) mm to (16.88 ± 5.92) mm at last follow-up, showing significant difference (t=2.822,P=0.026). Conclusion The technique of MPFL reconstruction is an effective surgical procedure for the treatment of recurrent patellar dislocation, which can improve the patella stabil ity and knee function.