Factors Influencing the Amount of ACL Remnant Available for Preservation at the Time of ACL Surgery: An Analysis of 5725 Knees From the SANTI Study Group Database.

Background: The preservation of the anterior cruciate ligament (ACL) remnant during reconstruction or repair could offer advantages such as enhanced vascularity, proprioception, and biomechanical properties. However, research on the clinical factors influencing ACL remnant preservation at the time of surgery is limited. Purpose/Hypothesis: The purpose was to identify clinical factors influencing the amount of ACL remnant during surgery. It was hypothesized that not solely the delay from injury to surgery influences the amount of ACL remnant present at the time of surgery, but also other patient characteristics such as sex and age, as well as intraoperative findings. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective analysis of prospectively collected data was performed on patients who underwent arthroscopic ACL reconstruction between January 2013 and December 2022. ACL remnants were categorized based on their location into tibial attachment, midsubstance, and femoral attachment, accounting for 20%, 60%, and 20% of the total ACL length, respectively. A multivariate logistic regression was performed to identify factors predictive of the amount of ACL remnant. Results: In a cohort of 5725 patients, different variables were associated with an ACL remnant <20% at the time of surgery. Patients aged ≤20 years had an odds ratio of 1.748 (95% CI, 1.473-2.075; Conclusion: Increased age at surgery was positively associated with a remnant size ≥20% of the ACL. Female sex, longer delay between accident and surgery, and associated injuries of intra-articular structures were risk factors for a remnant size <20%.