Two Belgium orthopedic surgeons have discovered a previously unknown ligament they believe could be responsible for many common knee injuries. The new ligament was not discovered with the assistance of high resolution scanners or subatomic lasers, but rather, the doctors took their cues from an article published in 1879 by a French surgeon who theorized the existence of an additional ligament located on the front part of the knee. 

Dr. Steven Claes and Dr. Johan Bellemans  began dissecting numerous cadavers until their search uncovered a tiny band of connective tissue they’ve named the anterolateral ligament, or ALL for short.

The doctors wrote in the Journal of Anatomy that they believe the ALL is found in 97 percent of all human knees and it appears to give way during anterior cruciate ligament tears:  a common sports injury that usually occurs when someone stops short or makes a sudden sharp turn.


In an email to the National Post, Dr. Bellemans said that the practical medical applications of the discovery are still taking shape. The implications for athletes are obvious. The discovery of the ALL may be a key breakthrough for older patients who’ve gone through knee replacements. 

 “We know today that a number of patients continue to experience discomfort and instability after knee replacement even despite successful surgery, which may be related to (previously unrealized) damage of the anterolateral ligament during surgical exposure for prosthetic insertion. We are currently looking into this, hoping to help our patients by improving the way we operate on them while preserving the structures that are vital for maintaining their knee joint.”

The Anatomical Society, which published the article in their journal, praised the research as “very refreshing” and commended the researchers for reminding the medical world that, despite the emergence of advanced technology, there is more to learn about the human body.