Biomechanical impact of lateral meniscus pathology on anterior cruciate ligament stress: a finite element analysis

Horizontal cleavage tears (HCTs) of the lateral meniscus are common injuries that can significantly affect knee biomechanics and increase stress on the anterior cruciate ligament (ACL). Understanding these changes is crucial for effective clinical management, as they can lead to joint instability and an increased risk of further injury. Finite element analysis (FEA) enables a detailed and non-invasive examination of these complex interactions.

The purpose of this study is to assess how partial HCTs of the lateral meniscus influence ACL stress. Using a validated finite element model, we aim to compare the mechanical implications of intact knees, knees with partial tears, knees with complete tears, and post-meniscus transplantation. We hypothesize that HCTs will increase contact pressures and decrease knee joint stability, thereby increasing stress on the ACL.

A detailed three-dimensional FEA model of the knee was developed, based on cadaveric CT anatomy. We analyzed four scenarios: intact knees, partial HCTs, complete tears, and meniscus transplantation under various axial loads (200 N, 400 N, 600N, 800 N) at both 0° and 30° of knee flexion. Key metrics evaluated included lateral meniscus contact pressures and von Mises stress in both the ACL and menisci, with careful extraction and analysis of stress distributions.

Our findings indicated that complete lateral meniscus tears resulted in increased stress on the lateral meniscus and decreased contact pressure at the ACL, particularly under the highest load (800 N). While meniscus transplantation reduced some of the stress compared to the torn state, it did not fully restore biomechanical function to baseline levels. Notably, stress increases were more significant and pronounced with lateral tears than with cruciate injuries, highlighting the unique implications of lateral pathology.

This study confirms that lateral meniscus HCTs alter ACL stress, highlighting the importance of clinical awareness of these biomechanical implications in injury management. The results suggest that treatment strategies for lateral HCTs should prioritize preserving meniscal integrity to maintain knee joint function and stability.