Outcome Differences of Remnant- Preserving versus Non-Preserving Methods in Arthroscopic Anterior Cruciate Ligament Reconstruction: A Meta-analysis with Subgroup analysis

PURPOSE: To analyze differences in clinical outcomes of arthroscopic anterior cruciate ligament reconstruction between remnant-preserving and non-preserving methods. METHODS: International electronical databases PubMed, Embase, and the Cochrane central database from January 1966 to December 2017 were searched for randomized controlled trials (RCTs) and observational studies that compared differences of clinical outcomes of ACL reconstruction with and without remnant preservation. A meta-analysis of these studies was performed to compare clinical outcomes. Subgroup analyses were conducted to evaluate the role of methodological quality in primary meta-analysis estimates. RESULTS: Five RCTs and six observational studies were included in this meta-analysis and subgroup analysis. The remnant-preserving method in arthroscopic ACL reconstruction showed a statistically significant difference compared to the non-preserving method regarding arthrometric evaluation (side-to-side difference). Lachman test, Lysholm scores, and IKDC subjective scores showed statistically minor difference in meta-analysis, but showed no significant difference in subgroup analysis. Remained parameters including pivot shift test, IKDC grades, incidence of cyclops lesion showed no statistically differences in meta-analysis or subgroup analysis. CONCLUSIONS: This meta-analysis with subgroup analysis showed that arthroscopic remnant-preserving ACL reconstruction provided statistically significant but limited clinical relevance in terms of arthrometric evaluation. Results of Lachman test, Lysholm scores, and IKDC subjective scores demonstrated statistically minor differences.