Medial Patellofemoral Ligament Reconstruction: Fixation Technique Biomechanics.

Abstract

Introduction The medial patellofemoral ligament (MPFL) is the primary soft-tissue stabilizer of the patella and it is often reconstructed in patients with recurrent patella instability. This biomechanical analysis evaluates the integrity of four methods of MPFL reconstruction subjected to cyclic loading using a porcine model. Methods Four techniques of MPFL reconstruction were analyzed using a 4 mm flexor tendon graft, all with two points of patellar fixation to best recreate the native MPFL anatomy. The four techniques were: (1) interference screw technique, (2) suture anchor technique, (3) converging tunnel technique, and (4) two bone tunnel technique. Maximum load, yield load, and stiffness of the graft fixation/bone complex were analyzed, and statistics were performed with SPSS and significance set at a p-value of < 0.05. Results The converging tunnel technique demonstrated the highest maximum load and yield load, significantly higher than the interference screw or suture anchor groups (p = 0.007). In addition, the converging tunnel technique demonstrated the greatest stiffness with significantly greater stiffness than the two bone tunnel techniques (p = 0.016). Conclusion The combination of strength and stiffness, the avoidance of patella implants, and the creation of a single transosseous tunnel make the converging tunnel technique a desirable technique for MPFL reconstructions.