There’s plenty of proof that rupture of the anterior cruciate ligament (ACL) or injury to the meniscus of the knee eventually leads to osteoarthritis (OA). To quote the authors of this report, pain and loss of function in middle-age results in a young patient with an old knee.
What can be done about this? There’s not enough evidence to support the idea that surgery to repair the damage prevents OA. Better understanding of the process of OA after injury might help direct future treatment.
This article gives a review of the literature on the long-term effects of knee injuries. Surgeons from Boston University School of Medicine and Lund University in Sweden discuss the reasons for wide ranging results after treatment.
Trauma resulting in ACL tear is usually very forceful. In fact, it is often enough to also cause injury of the meniscus, joint cartilage, and other ligaments. This may be the number one reason why OA is so common after ACL injury.
Other risk factors for the development of OA after knee injury have been found. These include age, family history, and joint shape. Work and leisure activities, obesity, and muscle weakness also increase the risk. The findings of many studies suggest that OA is the result of a combination of genetic and environmental factors.
Long-term outcomes after knee injury include signs of OA seen on X-rays and MRIs. Painful symptoms and loss of function are typical in over half of all patients with an ACL rupture and/or meniscus tears. This is true whether or not surgery was done to repair the damage.
The authors review in detail the pathologic processes that occur with knee injuries. Changes in the joint cartilage make the joint less able to handle loading.
The injured joint may never return to a normal rate of metabolism, which also affects load and function. In some cases, ligament injury occurs with minor or no apparent trauma and may actually be a part of the OA disease process.
The authors suggest that before changes can be made in the management of knee injuries, better studies are needed. Good quality, long-term trials that evaluate and compare treatment, costs, and report on outcomes are needed in this area.