ACL Reconstruction and the Development of Early Arthrosis
The anterior cruciate ligament (ACL) conveys substantial stability to the knee joint, predominantly in the prevention of excessive anterior tibial translation and internal rotation [1]. Without a functional ACL, the literature suggests a significant risk of progression to degenerative changes within the knee joint and subsequent development of osteoarthritis (OA). However, quantifying an incidence for this progression to osteoarthritis is difficult for a multitude of reasons including the numerous potential confounding variables and the length of time required to conduct an appropriate natural history study. One known contributing factor for early arthrosis is the high incidence of concomitant soft tissue and chondral injuries that often accompany an ACL tear, including meniscal and other ligamentous structures. Injuries to these structures further destabilize the joint and can expedite the progression of degenerative changes in an additive manner, particularly when those injuries cannot be repaired themselves. The activity level of patients post injury also likely plays a significant role in progression as highly active individuals will put a different level of stress on the knee joint over subsequent years than sedentary individuals, leading to advanced degenerative changes. Conversely, there is some literature to suggest that return to activities after ACL reconstruction (ACLR) may lead to lower rates of OA [2]. Perhaps most difficult for incidence tracking is the inherent issues in performing long-term studies to track OA progression based on the ability to physically track patients over a number of years as they change locations and providers. There is also debate as to whether ACLR with or without additional interventions can reduce the risk of OA progression after ACL rupture. This chapter focuses on the progression of OA after ACL injury, covering the basic science and biomechanical foundations as well as the surgical considerations that may impact the trajectory of OA progression in the injured knee.
