Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association | 2021
Anterolateral Structure Reconstruction Similarly Improves the Stability and Causes Less Over-constraint in ACL-Reconstructed Knees Compared with Modified Lemaire Lateral Extra-articular Tenodesis: A Biomechanical Study.
Abstract
PURPOSE\nTo compare the kinematics of anterolateral structure (ALS) reconstruction (ALSR) and lateral extra-articular tenodesis (LET) in ACL-ALS-deficient knees with anterior cruciate ligament (ACL) reconstruction.\n\n\nMETHODS\nTen fresh-frozen cadaveric knees with the following conditions were tested: (1) intact, (2) ACL-ALS deficiency, (3) ACL reconstruction (ACLR), (4) ACLR combined with ALSR (ACL-ALSR) or LET (ACLR+LET). Anterior translation and tibial internal rotation were measured with 90-N anterior load and 5 N·m internal torque at 0°, 30°, 60°, and 90°. The anterolateral translation and internal rotation were also measured during a simulated pivot-shift test at 0°, 15°, 30°, and 45°. The knee kinematic changes in all reconstructions were compared with each other, with intact knees as the baseline.\n\n\nRESULTS\nIsolated ACLR failed to restore native knee kinematics in ACL-ALS-deficient knees. Both ACL-ALSR and ACLR+LET procedures decreased the anterior instability of the ACLR. However, ACLR+LET caused over-constraints in internal rotation at 30° (-3.73°±2.60°, P=0.023), 60° (-4.96°±2.22°, P=0.001) and 90° (-6.14°±1.60°, P <0.001). ACL-ALSR also over-constrained the knee at 60° (-3.65°±1.90°, P <0.001) and 90° (-3.18°±2.53°, P <0.001). For a simulated pivot-shift test, both combined procedures significantly reduced the ACLR instability, with anterolateral translation and internal rotation being over-constrained in ACLR+LET at 30° (-3.32mm±3.89mm, P =0.005; -2.58°±1.61°, P <0.001) and 45° (-3.02mm±3.95mm, P =0.012; -3.44°±2.86°, P <0.001). However, the ACL-ALSR over-constrained only the anterolateral translation at 30° (-1.51mm±2.39mm, P=0.046) and internal rotation at 45° (-2.09°±1.70°, P <0.001). There were no significant differences between the two combined procedures at most testing degrees in each testing state, except for the internal rotation at 30° (P =0.007) and 90° (P=0.032) in internal rotation torque.\n\n\nCONCLUSION\nACL reconstruction alone did not restore intact knee kinematics in knees with concurrent ACL tears and severe ALS injury (ACL-ALS-deficient status). Both ACL-ALSR and ACLR+LET procedures restored knee stability at some flexion degrees, with less over-constraints in internal rotation resulting from ACL-ALSR.