Uncovering the Mechanisms of Soft Tissue Injuries Associated with ACL Tear

Abstract

An anterior cruciate ligament (ACL) tear is a common and painful injury that occurs 250,000 times annually in the U.S. Articular cartilage and meniscal injuries are associated with ACL injuries. ACL injuries, and the associated injuries, lead to degenerative osteoarthritis. An epidemiology study of athletic injuries by Majewski et al. determined that out of 19,530 sports injuries, 20% were ACL injuries and 8% were medial collateral ligament injuries. æPrevious research studies offer explanations of the ACL injury mechanism. These studies concluded that ACL injury occurs during landing with the knee near full extension, in valgus, and the femur externally rotated. These studies make the assumption that ACL injury occurs only in certain loading combinations. Despite ACL injury prevention strategies, the rate of injury occurrence is unchanged. This proves a lack of knowledge regarding knee ligament injury mechanisms. Our previous studies have shown that ACL injury occurs in a multitude of motion schemes. æThis study uses a 3D finite element knee joint model to highlight which of the previously deemed unfavorable motion schemes our research found for ACL injury, are likely to cause cartilage and meniscal injury. The study will provide a spectrum of injury propensity for these soft tissues, showing which injury mechanisms are likely to cause osteoarthritis in the long term. æIt is hypothesized that cartilage and meniscal injury will be more likely in valgus scenarios compared to varus scenarios. This is because the lateral compartment is smaller than the varus compartment, which could cause higher stress concentrations.