ACL surgeries are one of the more common procedures performed by sports medicine surgeons. It is estimated that between 100,000 and 175,000 ACL reconstructions are performed in the United States each year. It is an especially common injury in sports that involve cutting and pivoting maneuvers, landing from jumps, and tackling.
Most athletes have a straightforward goal after suffering an ACL injury – to return to sports. Many athletes would experience rotational instability of the knee and feel their knees buckle or give way with turning or landing, which would prevent playing effectively. Surgery to make a new ligament aims to restore stability.

One of the common questions I receive from weekend warriors and others who suffer these injuries centers around the development of osteoarthritis. But does ACL reconstruction actually prevent degenerative changes in the knee?

A study in the December 2011 issue of The American Journal of Sports Medicine actually suggests the opposite might be true. Ryan T. Li et al. looked at 249 patients who had undergone ACL reconstruction at an average of 7.8 years after surgery and found that 39% had developed radiographic evidence of osteoarthritis. They then looked at some of the underlying risk factors to attempt to determine which subgroups of patients were at increased risk of arthritis after undergoing these surgeries.

Among their findings, the authors found that the strongest predictors for its development included increased body mass index (BMI), having had or currently undergoing partial meniscectomy (trimming part of a meniscus tear out), presence of articular cartilage damage in the medial compartment (side of the knee closest to the midline), and increased time from injury to surgery.

Arthritis changes in the knee
Note the diffuse fraying of the articular cartilage, significant of early arthritis changes.

While this study might be discouraging to those of you who have suffered ACL injuries, keep in mind that you aren’t necessarily going to develop osteoarthritis. Yes, it is somewhat out of your hands in the sense that you have no control over whether you tear a meniscus or damage the articular cartilageat the time of injury. But you do have control over the length of time that elapses before treatment. Therefore, if you suffer an injury to the knee, especially one which involves a significant amount of swelling, pain, stiffness, or difficulty bearing weight, it seems worthwhile to see a sports medicine surgeon and determine the extent of injury. And while definitive conclusions are impossible, you could at least make an argument that an active patient, especially one who plays sports, should undergo surgery sooner rather than later to avoid secondary damage to the meniscus or cartilage.

The biggest factor that predisposed for osteoarthritis in this study was a high BMI. This essentially means that larger or overweight patients were more at risk. This fact makes sense in that these patients place more stress not only on the ACL grafts but also the menisci and articular cartilage. While it isn’t possible to affect changes to BMI after injury, it might be one of a number of reasons to try to keep weight optimal for sports.

Lastly, athletes love to play sports. Regardless of whether osteoarthritis develops in the years after injury, they still mostly want to get back on the field or court. For these athletes, and people who love exercise or physical activity, ACL reconstruction can be a good idea to allow them to do what they love. Is there a risk of developing degenerative changes in the knee? Yes, but even so, they likely have a good chance of returning to play – even if that means they could need further knee treatments in the future.