Objective To study the effect of the femoral tunnel position on the knee function recovery after medial patellofemoral ligament (MPFL) reconstruction. Methods A retrospective analysis was made on the clinical date of 43 cases (43 knees) of recurrent patellar dislocation undergoing MPFL reconstruction and patellofemoral lateral retinaculum lysis between August 2013 and March 2014. There were 12 males and 31 females, aged 19.4 years on average (range, 9-35 years). All patients had trauma history and recurrent dislocations. The results of apprehesion test and J syndrom were positive. The patellar tilt test showed patellofemoral lateral retinaculum was tension. The effectiveness was evaluated using Lysholm knee functional score after operation. The distance from the center of the femoral tunnel to the femoral isometric point was measured on CT three dimensional reconstruction image. Whether the femoral tunnel position was isometric was evaluated. The correlation was analyzed between the distance from the center of the femoral tunnel to the femoral isometric point and Lysholm score. Results Primary healing of incision was obtained in all patients. The patients were followed up 13-18 months (mean, 15 months). No patellar dislocation or subluxation occurred. The result of apprehensive test was negative. At last follow-up, the average Lysholm score was 93.8 (range, 83-100). The average distance from the center of the femoral tunnel to the femoral isometric point was 5.61 mm (range, 2-16 mm). The femoral tunnel position was isometric in 30 cases (69.8%) and non-isometric in 13 cases (30.2%). The distance from the center of the femoral tunnel to the femoral isometric point was negatively correlated with postoperative Lysholm score (r=-0.851, P=0.000). The postoperative Lysholm score was 95.7±2.3 in patients with isometric tunnel and was 89.4±3.5 in patients with non-isometric tunnel, showing significant difference (t=6.951, P=0.000). Conclusion For patellofemoral joint instability, preparing the femoral isometric tunnel can establish a good foundation for the recovery of the knee function in MPFL reconstruction.

Citation： A Yiding·XIA Hatai, ZHANGKeyuan, LIUYang. EFFECTS OF FEMORAL TUNNEL POSITION ON KNEE FUNCTION AFTER MEDIAL PATELLOFEMORAL LIGAMENT RECONSTRUCTION. Chinese Journal of Reparative and Reconstructive Surgery, 2015, 29(8): 951-954. doi: 10.7507/1002-1892.20150205 Copy