Histological Changes in Ruptured Anterior Cruciate Ligament: A Comparative, Prospective, Observational Study in Different Age Groups and Time of Presentation Since Injury

Anterior cruciate ligament (ACL) injury is one of the most common sports-related injuries. Because of its intra-capsular location, it has very little chance of healing following injury. The causes of poor healing of ACL tears are mostly due to poor vascularity, disorganized collagen bundles, insufficient myofibroblast proliferation, etc. The healing potential is also varied in different age groups like any other tissue. Here, we studied the histological changes in ACL remnants that occur after ACL injury in different age groups and with varied times of presentation since injury. It was a prospective observational study comparing the histopathology of ACL remnants in 12 subgroups of cases. Healthy synovial lining, presence of inflammatory cells, neo-vascularization, and myofibroblasts are needed for natural healing of ACL. We found a favorable environment for the healing of ACL in younger patients with an injury period of one to three months. We suggest cases with a partial tear of ACL in a young individual presented within one to three months duration may be encouraged for conservative treatment or ACL repair surgery rather than ACL reconstruction. Our initial study on the histopathology of torn ACL has added insight into the existing literature and further studies are needed to substantiate its further application.