The effects of popliteus tendon and popliteofibular ligament reconstruction in an external rotation injury model of the knee

Abstract

Objective To investigate the effects of the popliteofibular ligament (PFL) and/or the popliteus tendon (POP) reconstruction in an external rotation injury model of the knee.Methods Six nonpaired cadaveric knees were tested under the following POP and PFL states:intact,sectioned,and reconstructed using 3 different techniques.Each knee was subjected to 5 N·m external rotation torque at flexion angles of 0°,30°,45°,60°,90°,and 120°.A navigation system was used to measure the motion changes of the tibia with respect to the femur.Results The external rotation increased 2.1°±0.7° (2.0°-2.3°) after sectioning only PFL while flexing the knee from 30° to 120°,and increased 1.3°±1.2° (0.5°-2.0°) after sectioning only POP while flexing the knee from 30° to 120°.There was no significant difference between two groups.There was significant increase in external rotation as 4.1°±1.6° (2.8°-5.0°) after sectioning both POP and PFL.Comparing the POP and POP+PFL reconstruction techniques to the intact state,there were significant differences.The external tibial rotation in POP or POP+PFL reconstruction group was significant different from that in intact or PFL reconstruction group while flexing the knee from 30° to 90°.Conclusion In a LCL-intact PLC injury model,the POP and PFL function as a unit in resisting external rotation.All surgical procedures we described and tested are able to reduce the increased external rotational laxity found in the sectioned state.The PFL reconstruction is able to restore external rotation to near normal.However the techniques involving POP reconstruction over constrained external rotation during laxity testing. Key words: Knee joint; Joint instability; Biomechanics; Reconstructive surgical procedures