Osteoarthritis following meniscus and ligament injury: insights from translational studies and animal models

Purpose of review The interaction between joint injuries and posttraumatic osteoarthritis (PTOA) is generally thought to be mechanical in nature, however, surgical intervention has little effect on the development of PTOA. Little is known about the biological underpinning of how meniscus and anterior cruciate ligament (ACL) tears lead to cartilage degeneration. This review summarizes the latest findings regarding biological factors that influence how the knee responds to meniscus and ligament injuries, how meniscus and/or ACL tears turn the joint in the direction of PTOA and whether patient risk for PTOA after meniscus/ACL injury can be predicted. Recent findings Literature indicates that numerous intrinsic and extrinsic factors are associated with the biological response of the knee to injuries associated with PTOA. Gene/protein biomarkers provide insight into the biologic response of the knee to meniscus/ACL tears and the relationship to osteoarthritis in at-risk patients. Animal studies detail the time-course of disease pathogenesis and inform about the molecules that potentially alter the course of disease. Summary The molecular metabolic state of the meniscus/ACL after injury is associated with several biological factors. The limited studies to date provide initial evidence on the early molecular manifestations of injury, suggesting possible mechanisms for further study.