Clinical Effect of Posterior Obliqueligament Repair in Anterior Cruciate Ligament Reconstruction Combined With Medial Collateral Ligament Repair: A Retrospective Comparative Study

Abstract

The stability of the knee joint following anterior cruciate ligament (ACL) restoration combined with medial collateral ligament (MCL) injury repair is crucial. It is yet unknown how posterior oblique ligament (POL) suturing functions in these procedures. This study aimed to assess the impact of POL repair on knee joint stability in patients undergoing ACL reconstruction with MCL repair. We hypothesised that POL repair would further enhance knee joint stability compared to conservative treatment in patients with combined ACL and MCL injuries. A total of 104 patients with ACL and grade III MCL injuries were enrolled and divided into the experimental group (n = 53, POL repair) and the control group (n = 51, conservative treatment for POL injury). Knee stability was assessed using Ligs Digital Arthrometer (measuring tibial displacement and medial separation) and the Dial test (measuring external tibial rotation). Knee function was evaluated with IKDC, Lysholm, VAS and ROM scores at baseline and 12-month follow-up. Both groups showed significant improvements in tibial displacement (ACL SSD) and medial separation (MCL SSD) after surgery compared to baseline (p < 0.05). However, intergroup comparisons indicated no statistically significant changes in knee stability metrics (p > 0.05). Functional scores (IKDC, Lysholm, ROM and VAS) improved considerably in both groups from baseline, with no significant differences between groups (p > 0.05). The Dial test revealed a substantial decrease of external tibial rotation in both groups postoperatively, with no intergroup variations. While ACL reconstruction and MCL repair significantly improved knee joint stability, POL suturing did not have a significant impact on the overall knee stability in patients with ACL and MCL injuries.