Biomechanical Study Of The Three Different Reconstruction Of Superficial MCL (sMCL) And Posterior Oblique Ligament(POL)

Purpose:The postermedial structure of knee is an important part for the medial stability structure of knee. superficial MCL(s MCL) and Posterior Oblique Ligament(POL) are the important parts of the postermedial structure of knee,both to maintain valgus and rotational stability of the knee.At present, we choose anatomic reconstruct the s MCL and POL to treat the damaged postermedial structure.But postoperative results are still differences compared with the intact knee.The purpose of this study was to evaluate and compare the resulting knee kinematics and stability of superficial MCL(s MCL) and Posterior Oblique Ligament(POL) long-arm triangular reconstruction and short-arm triangular reconstruction and a new combinative reconstruction.Methods:In a cadaveric model, normal knee stability and kinematics were compared with s MCL and POL deficient knees and with three experimental s MCL and POL reconstructions. The first reconstruction attempted to long-arm triangular reconstruct the s MCL and POL. The second reconstruction attempted to short-arm triangular reconstruct the s MCL and POL;The third reconstruction attempted to combinative triangular reconstruct the s MCL and POL. Changes in position of the femur with respect to the tibia(0°,30°,60°,90°)were measured with an CSS-44020 biomechanics torsion testing instrument during passive knee stability testing in the s MCL and POL intact knee, the s MCL and POL deficient knee, and the three experimental reconstructions.Results: A significant increase was found in valgus angulation,external rotation after sectioning the medial knee structures at all tested knee flexion angles. valgus angulation range(5.5°~8.6°);external rotation range(3.9°~10.0°).A significant increase was found in internal rotation at tested knee flexion angles in the 30°,60°.Additionally, passive stability testing demonstrated a significant increase in external tibial rotation of Short-arm reconstruction compared to intact knee at 60° and 90°of knee flexion,but a significant increase in tibial valgus of Long-arm compared to intact knee at 0°. combinative s MCL and POL reconstruction would provide a better result at all tested knee flexion angles.Conclusion:The three reconstruction of the s MCL and POL effectively restored knee kinematics and stability in the s MCL and POL deficient knee. Altering the operation method resulted in measurable changes in knee kinematics and stability. This study suggests that in cases of s MCL and POL injury, the combinative s MCL and POL reconstruction would provide a better result.