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Published on: October 20, 2023
Lateral Meniscus Posterior Root Repair with Lateral Extra-articular Tenodesis Significantly Decreased Internal
Wybren A van der Wal1, Luke V Tollefson2, Roy A G Hoogeslag3
1Sports Valley, Department of Orthopedic Surgery, Gelderse Vallei Hospital, Ede, The Netherlands.
Purpose:
To determine the biomechanical effects of lateral meniscus posterior root- (LMPR) and Kaplan fiber tears in anterior cruciate ligament-(ACL) deficient knees and assess the impact of LMPR repair, modified Lemaire lateral extra-articular tenodesis, or both, after ACL reconstruction (ACLR).
Methods:
Ten paired cadaveric knees were randomized into four groups and mounted in a six degrees of freedom robotic system. The ACL, LMPR, and Kaplan fibers were sequentially sectioned in random order. After ACLR, LMPR repair and Lemaire were performed in random order. Tibial displacements and rotations were measured under internal rotation (IR) torque and a simulated pivot shift at 0°-90° knee flexion.
Results:
ACLR alone did not fully restore stability, with significant residual increases in isolated IR between 15° and 90° (all P < .001), coupled IR at all flexion angles (all P < .01), coupled anterior tibial translation (ATT) between 0° and 45° (all P < .05), and coupled valgus rotation between 15° and 90° (all P < .003) during pivot shift. Adding Lemaire to ACLR, without or with LMPR repair, restored stability comparable to the intact knee for isolated IR (without, all P > .086; with, all P > .132), coupled IR (without, all P > .102; with, all P > .172), and coupled ATT (without, all P > .537; with, P > .872) during pivot shift. LMPR repair in ACLR with Kaplan fiber injury restored valgus rotation stability at most flexion angles (all P > .053).
Conclusions:
Both the LMPR and Kaplan fibers act as secondary stabilizers to IR and pivot shift loading in the ACL deficient knee, with an additive biomechanical effect of the Kaplan fibers to the ACL with LMPR deficient knee for isolated IR and for coupled IR and ATT during pivot shift. Furthermore, the most important reconstruction state which best restored stability comparable to the ACL intact state was the addition of lateral extra-articular tenodesis to either the ACLR alone or ACLR with LMPR repair state, except for valgus rotation during pivot shift, where LMPR repair contributes most.
Clinical Relevance:
Both LMPR repair and anterolateral corner reconstruction are necessary to restore stability in knees with ACL, Kaplan fiber, and LMPR injuries.
