[Reconstruction of medial patellofemoral ligament for recurrent patellar dislocation]

To investigate the procedure and effectiveness of medial patellofemoral ligament (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 tibialis tendon. There were 6 males and 23 females with an average age of 20.3 years (range, 13-45 years). The patients suffered from 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 Elmslie-Trillat osteotomy was performed to correct the distal alignment of patella. The arthroscopic examination was also performed for loose body and lateral retinacular release.

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 degrees and 30 degrees 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 < 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, TT-TG 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).

The technique of MPFL reconstruction is an effective surgical procedure for the treatment of recurrent patellar dislocation, which can improve the patella stability and knee function.