A Comprehensive Meta-analysis of Clinical and Biomechanical Outcomes Comparing Double-Bundle and Single-Bundle Posterior Cruciate Ligament Reconstruction Techniques

Abstract

Background: Posterior cruciate ligament (PCL) reconstruction techniques have historically focused on single-bundle (SB) reconstruction of the larger anterolateral bundle without addressing the codominant posteromedial bundle. The SB technique has been associated with residual laxity and instability, leading to the development of double-bundle (DB) reconstruction techniques. Purpose: To perform a meta-analysis of comparative clinical and biomechanical studies to differentiate the pooled outcomes of SB and DB PCL reconstruction cohorts. Study Design: Meta-analysis and systematic review: Level of evidence, 3. Methods: Six databases were queried in February 2022 for literature directly comparing clinical and biomechanical outcomes for patients or cadaveric specimens undergoing DB PCL reconstruction against SB PCL reconstruction. Biomechanical outcomes included posterior tibial translational laxity, external rotational laxity, and varus laxity at 30° and 90° of knee flexion. Clinical outcomes included the side-to-side difference in posterior tibial translation during postoperative stress radiographs, risk of a major complication, and the following postoperative patient-reported outcome measures: Lysholm, Tegner, and International Knee Documentation Committee (IKDC) subjective and objective scores. A random-effects model was used to compare pooled clinical and biomechanical outcomes between the cohorts. Results: Fifteen biomechanical studies and 13 clinical studies were included in this meta-analysis. The DB group demonstrated significantly less posterior tibial translation at 30° and 90° of knee flexion ( P < .00001). Additionally, the DB group demonstrated significantly less external rotation laxity at 90° of knee flexion ( P = .0002) but not at 30° of knee flexion ( P = .33). There was no difference in varus laxity between the groups at 30° ( P = .56) or 90° ( P = .24) of knee flexion. There was significantly less translation on stress radiographs in the DB group ( P = .02). Clinically, there was no significant difference between the groups for the Lysholm score ( P = .95), Tegner score ( P = .14), or risk of a major complication ( P = .93). DB PCL reconstruction led to significantly higher odds of achieving “normal” or “near normal” objective IKDC outcomes for the included prospective studies ( P = .04) and higher subjective IKDC scores ( P = .01). Conclusion: DB PCL reconstruction leads to superior biomechanical outcomes and clinical outcomes relative to SB PCL reconstruction. Re-creating native anatomy during PCL reconstruction maximizes biomechanical stability and clinical outcomes.