Comparing Clinical Outcomes and Knee Stability in Remnant-Preserving ACL Reconstruction Versus Standard ACL Reconstruction: A Systematic Review and Meta-analysis

Background: Anterior cruciate ligament reconstruction (ACLR) is one of the most frequently performed procedures in sports medicine, and undesirable outcomes still may range from 3-18%. One technique that has been explored to improve outcomes is preservation of the ACL remnant tibial stump, as opposed to stump debridement, at the time of reconstruction. Purpose: To review current high-level evidence and compare remnant-preserving anterior cruciate ligament reconstruction (ACLR) versus standard ACLR in terms of clinical outcomes and measures of knee stability. Hypothesis: ACLR with remnant preservation would result in improved clinical outcomes and knee stability measures. Study Design: Systematic review; Level of evidence, 2. Methods: A systematic review of randomized controlled trials (RCTs) and cohort studies comparing remnant-preserving ACLR with standard ACLR with a minimum level of evidence of 2 was performed. Extracted data were summarized as general information, surgical characteristics, postoperative clinical outcomes, knee stability, graft evaluation, tunnel assessment, and postoperative complications. When feasible, a meta-analysis was performed. Results: Seven RCTs and 5 cohort studies met the inclusion criteria. In total, 518 patients underwent remnant-preserving ACLR and 604 patients underwent standard ACLR. Ten studies performed the reconstruction with hamstring tendon (HT) autografts, 1 study with HT and bone–patellar tendon–bone autografts, and 1 study with HT and tibialis anterior allografts. On meta-analysis, remnant-preserving ACLR provided comparable outcomes with respect to International Knee Documentation Committee grades or Tegner scores. Even though there was a significant improvement in Lysholm scores (mean difference, −1.9; 95% CI, −2.89 to −0.91; P = .0002) with the remnant-preserving technique, this did not exceed previously reported minimal clinically important difference values. Remnant-preserving ACLR demonstrated superior knee stability in terms of patients achieving negative pivot shift when compared with the control group (88.89% vs 79.92%; P = .006). Although there was a significant improvement in the side-to-side difference in anterior tibial translation favoring remnant preservation (P = .004), the mean difference was 0.51 mm. Conclusion: Remnant-preserving ACLR, primarily with HT autografts, results in comparable clinical outcome scores and significantly improved knee stability relative to standard ACLR without remnant