Double-Bundle Anterior Cruciate Ligament Reconstruction With Lateral Extra-Articular Tenodesis Is Effective in Restoring Knee Stability in a Chronic, Complex Anterior Cruciate Ligament-Injured Knee Model: A Cadaveric Biomechanical Study

Purpose: To compare knee stability after intra-articular isolated double-bundle (DB) anterior cruciate ligament reconstruction (ACLR) and single-bundle (SB) and DB ACLR combined with lateral extra-articular tenodesis (LET) in a chronic, complex anterior cruciate ligament (ACL)–injured knee model. Methods: In 10 fresh-frozen cadaveric knees, we measured knee laxity in the following order: (1) intact knee; (2) ACL-sectioned knee; (3) complex ACL-injured knee model with additional sectioning of the anterolateral complex and the posterior horns of the medial and lateral menisci; (4) SB ACLR plus LET; (5) DB ACLR; and (6) DB ACLR plus LET. Results: In comparison with the intact knee, significantly increased internal rotation (IR) laxity persisted at 60° and 90° after DB ACLR (P =.002 and P =.003, respectively). SB ACLR plus LET and DB ACLR plus LET resulted in significant reductions in IR laxity at 90° (P =.003 and P =.037, respectively), representing overconstraint in IR. SB ACLR plus LET resulted in persistently increased external rotation (ER) laxity at 30°, 60°, and 90° (P =.001, P <.001, and P <.001, respectively). The DB ACLR condition persistently showed significant increases in anterior tibial translation laxity at 60° and 90° (P =.037 and P =.024, respectively). A greater increase in ER laxity was seen after SB ACLR plus LET versus DB ACLR plus LET at 30°, 60°, and 90° (P <.001, P <.001, and P <.001, respectively). Conclusions: DB ACLR plus LET restored intact knee stability in IR, ER, and anterior tibial translation laxity at 0°, 30°, 60°, and 90° of knee flexion except for overconstraint in IR at 90° in a chronic, complex ACL-injured knee model. Clinical Relevance: This cadaveric study provides some biomechanical evidence to support performing DB ACLR combined with LET to restore knee stability after a complex, chronic knee injury involving an ACL tear combined with anterolateral complex injury and irreparable tears of the posterior horns of the medial and lateral menisci.