Attention, physical therapists: Two orthopedic surgeons at the University Hospitals in Belgium recently discovered a new knee ligament now known as the anterolateral ligament (ALL). The New York Times reported that Dr. Steven Claes and Dr. Johann Bellemans found that the fifth ligament located on the anterior portion of the knee connects the femur to the tibia and helps to control its rotation. As early as 1879, a French surgeon suspected that this additional knee part – a “pearly, resistant fibrous band” – may exist, and the Belgian physicians confirmed existence of the ALL by examining the knees of 41 human cadavers.

The newly discovered ligament may provide insight into why some patients continue to experience knee problems even after anterior cruciate ligament (ACL) surgery. According to NBC News Health, some people with torn anterior cruciate ligaments (ACLs) suffer what is known as “pivot shift,” where the knee gives way when it is moved a certain way. Researchers began to suspect that the knee might have an additional ligament when some of their patients who had undergone ACL surgery experienced this pivot shift, even though the ACL appeared to be healing properly.

“We thought, something is still not right,” said Dr. Claes in the New York Times article. The researchers now believe that the pivot shift may be caused by an injury to the ALL.

Dr. Claes and Dr. Bellemans believe it is very likely that many people with torn ACLs also have torn ALLs and that if the ALL is left untreated, joints could remain unstable. Although they are currently investigating potential surgical treatments for torn ALLs, they admit that there are still many unanswered questions, including whether or not the ALL can heal without surgery.

The findings of this study were published in the Journal of Anatomy, Volume 223, Issue 4.

By Kindred Hospital Rehabilitation Services