Clinical effects of different remnant‐preserving versus standard nonpreserving techniques in anterior cruciate ligament reconstruction: A systematic review and meta‐analysis

Abstract Purpose In anterior cruciate ligament reconstruction (ACLR), the clinical benefits and limitations of nonpreserving versus different remnant‐preserving ACLR are not well defined. There is also a lack of systematic analysis of ACL remnant length. Methods Database searches were performed in PubMed, Embase, Web of Science and Cochrane CENTRAL from inception to 25 April 2025. Risk of bias was assessed using the Cochrane Collaboration's tool and the Newcastle‐Ottawa scale (NOS) critical appraisal tools. Certainty of evidence was evaluated using the grading of recommendations assessment, development and evaluation (GRADE) framework. The reported outcomes used for analysis included stability‐related indicators, functional scores, synovial coverage and complications. Subgroup analyses were performed across three remnant‐preserving surgical approaches: Augmentation, tension and sparing. Meta‐regression and network meta‐analyses were performed to investigate whether improved outcomes were associated with remnant length. Sensitivity analysis was used to assess the robustness of the results. Results Our analysis included 36 articles. For stability, the remnant‐preserving (R) group showed improved outcomes compared to the nonremnant (NR) group in the Lachman test (weighted mean difference [WMD] = 1.61, p = 0.0003), Side‐to‐side anterior laxity (SSD, WMD = −0.27, p = 0.03) and Pivot shift test (WMD = 1.34, p = 0.03), with the highest improvement observed in the Sparing subgroup. For functional scoring, the R group exhibited significantly higher Lysholm knee scoring scale scores (WMD = 1.52, p = 0.01), Tegner athletic ability evaluation score (WMD = 0.40, p < 0.00001), and International Knee Documentation Committee (IKDC) subjective scores (WMD = 1.00, p = 0.001), with the Tension subgroup showing the highest overall improvement. The R group also achieved better synovial coverage (odds ratio [OR] = 2.00, p = 0.0004) and lower failure (OR = 0.48, p = 0.002), particularly in the augmentation subgroup. Meta‐regression indicated a correlation between increased graft length and reduced SSD ( β = −1.33, p = 0.01), improved IKDC scores ( β = 20.03, p = 0.01), and fewer complications ( β = −2.61, p = 0.01). Network meta‐analysis indicated a 75% remnant preservation ratio minimised SSD alongside enhanced functional scores. Conclusion Remnant‐preserving ACLR showed improvements in stability and synovial coverage. However, in terms of clinical outcomes, the improvement in functional recovery has not reached a significant level. Sparing exceled in improving stability, while augmentation effectively reduced failure and tension favoured function. Increasing remnant preservation length significantly improved stability and function concomitantly reducing complications. Clinical Trials CRD42024550746. Level of Evidence Level III.