Posterior Cruciate Ligament Reconstruction With Transtibial or Tibial Inlay Techniques: A Meta-analysis of Biomechanical and Clinical Outcomes

Background: Transtibial (TT) or tibial inlay (TI) techniques are commonly used for posterior cruciate ligament reconstruction (PCLR). However, the optimum method for PCLR after PCL injury remains debatable. Hypothesis/Purpose: The hypothesis was that TT and TI techniques would not show significant differences for all outcome measures. The purpose was to determine the biomechanical and clinical outcomes of TT and TI surgical techniques for PCLR. Study Design: Meta-analysis; Level of evidence, 3. Methods: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and SCOPUS electronic databases for articles published up until August 2016 were searched to find relevant articles comparing outcomes of TT versus TI techniques for PCLR. Data searching, extraction, analysis, and quality assessment were performed according to Cochrane Collaboration guidelines. Biomechanical outcomes and clinical outcomes of both techniques were compared. Results are presented as risk ratio (RR) for binary outcomes and weighted mean difference (WMD) for continuous outcomes with 95% confidence intervals (CI). Results: Five biomechanical and 5 clinical studies were included. No significant biomechanical differences were found regarding posterior tibial translation (PTT) at a knee flexion angle of 90° or PTT after cyclic loading between the 2 groups. However, a stronger in situ force in the graft was detected in the TT group (WMD = 15.58; 95% CI, 0.22-30.95; I² = 10%). Although no significant differences were found in clinical outcomes such as Lysholm knee function score, Tegner activity score, side-to-side difference, or posterior drawer test at final follow-up between the 2 groups, the TT technique tended to entail fewer perioperative complications than the TI technique (RR = 0.60; 95% CI, 0.35-1.00; I² = 0%). Conclusion: TT and TI techniques for PCLR can both restore normal knee kinematics and improve knee function. However, the issue of which yields better improvement in stability and functional recovery of the knee remains unclear. More high-quality trials and randomized controlled trials are needed. Although PCLR via the TT technique resulted in higher graft forces, determining whether this is clinically significant will require further studies. When performing the TI technique, surgeons should inform patients of the risk of complications.