Unhealed Anterolateral Ligament of the Knee is Associated with Residual Pivot-Shift Following Anterior Cruciate Ligament Reconstructions

Purpose:The association between the healing of an injured anterolateral ligament (ALL) and residual pivot-shift following anterior cruciate ligament (ACL) reconstructions is rarely reported.This study analyzed the relationship between unhealed ALL and residual pivot-shift after an ACL reconstruction.Materials and Methods: The inclusion criteria were patients who underwent autologous hamstring ACL reconstructions within 6 weeks after injury from January 2008 to March 2021.Preoperative ALL injuries and postoperative ALL healing were graded according to the magnetic resonance imaging classification, with postoperative magnetic resonance imaging performed 7.8 months after surgery on average.The patients were categorized based on postoperative ALL healing, and the clinical scores (Lysholm score and Tegner activity scale) and knee stability (Lachman test and pivot-shift test) were assessed at the 1-year postoperative follow-up.Results: One hundred and forty-five patients were enrolled in this study.One hundred and twenty-eight (88.3%) patients had a concomitant ALL injury.Among 86 patients with preoperative grade B, 16 (18.6%)patients showed grade 1 (good), and 70 (81.4%)showed grade 2 (partial) ALL postoperatively.Among the 42 patients with preoperative grade C (complete tear), 1 (2.4%) patient showed grade 1 (good), 21 (50.0%)showed grade 2 (partial), and 20 (47.6%) showed grade 3 (non-visualized) ALL.Preoperative grade C was significantly associated with a higher incidence of grade 3 (non-visualized) postoperatively than the other groups (p<0.001).Postoperatively, the Lachman test, KT-1000 (MEDmetric Corp.) arthrometer (side-to-side difference), Lysholm score, and Tegner activity scales did not show a significant difference among the intact, grade 1, grade 2, and grade 3 ALL groups.The pivot-shift test showed a significant difference between the ALL grades (p=0.001).Grade 3 ALL group showed a higher incidence of pivot-shift than the intact, grade 1, and grade 2 ALL groups.Conclusion: Patients with preoperative grade C had a higher rate of grade 3 postoperatively compared to the other groups.In addition, the grade 3 group had a significantly higher incidence of a pivot-shift.Therefore, in cases of ACL injuries with concomitant complete ALL tears, ALL reconstruction should be considered during ACL reconstruction.