Finite element analysis of medial meniscus tears and related surgical techniques with biomechanical validation.

Introduction: This study established finite element models of the knee incorporating radial and longitudinal meniscal tears and simulated corresponding surgical techniques to investigate the influence of different tear types, lengths, locations on stress distribution in the knee joint and evaluate the restorative effects of different surgical techniques on the biomechanical performance of the meniscus. Methods: A three-dimensional finite element model of the right knee including bone and soft tissues was developed. Stable and unstable radial and longitudinal tear models were created in the posterior horn of the meniscus across three zones (white-white, red-white, and red-red zones), together with the corresponding surgical technique models (suture repair and partial meniscectomy). Finite element analysis was performed under static loading. A cadaveric knee biomechanical experiment was also conducted to validate the finite element model. Results: Under static loading, the discrepancy in medial compartment contact area between the finite element model and the cadaveric experiment under intact meniscus conditions was 5.72%. The peak contact pressure was highest in the unstable radial tear model, reaching 14.88 MPa, representing an 181.82% increase compared with 5.28 MPa measured in the intact meniscus. Both repair and partial meniscectomy significantly reduced the peak contact pressure in the medial meniscus and tibial cartilage for radial tears. Repair reduced the peak pressure by 35.35% for stable radial tears, while partial meniscectomy reduced it by 49.60% for unstable radial tears. Meniscal repair reduced the peak contact pressure by 4.55% and 3.85% for stable longitudinal tears located in the red and white zones, respectively, and restored hoop stress transmission. Partial meniscectomy reduced the peak contact pressure by 7.90% (0.67 MPa) for unstable longitudinal tears located in the white zone. Conclusion: Stress distribution in the meniscus and its components is influenced by tear types, locations, lengths, and surgical technique. Surgical outcomes significantly depend on tear types, lengths, and locations. The extent of biomechanical restoration varies considerably among different surgical techniques, suggesting that clinical procedure selection should be based on personalized consideration of injury characteristics.