Quantifying the current impact of listing ACL reconstructions as low priority on subsequent meniscal pathology

Anterior cruciate ligament (ACL) ruptures can cause knee instability, potentially leading to meniscal and chondral injury if left untreated. Recent guidance suggests listing ACL reconstruction as lower priority without meniscal pathology. This study examines the risk of subsequent meniscal tears with delayed surgery.

We conducted a retrospective cohort study (January 2018-March 2024) of consecutive patients who underwent ACL reconstruction. Patients were categorised by preoperative magnetic resonance imaging (MRI) findings of meniscal tears, and time from listing to surgery. Intraoperative findings of meniscal tears were recorded. Nonparametric testing and binary logistic regression determined risk factors for meniscal pathology with delayed surgery.

Among 272 patients, 15.1% had new meniscal tears identified intraoperatively that were absent on initial MRI scan, with a male-to-female ratio of 3:1. Additionally, 5% had MRI-detected pathology not confirmed surgically. Median time to diagnosis was 21 days, and median time to surgery was 140 days. Age and time to diagnosis did not affect outcomes (p>0.05). Body mass index (BMI) differences were not significant overall but became significant when outliers (BMI>43) were excluded (p=0.038). Logistic regression, adjusting for sex and BMI, showed a 0.3% increase in meniscal tear risk per waiting day (p=0.013).

This study highlights the risk factors and progression of meniscal tears following delayed ACL reconstruction. Patient BMI and waiting list duration are important factors for risk reduction. With a delay of a month to surgery, the likelihood of developing a meniscal tear increases by nearly 10%. These findings emphasise the importance of early intervention, and potential re-evaluation of the current guidance.