Doctors Discover A New Knee Ligament

ABCNews.com—November 6, 2013

How did doctors miss this one for so long? Two Belgium orthopedic surgeons have discovered the existence of a previously unknown ligament that may be responsible for many common knee injuries.

Starting with an 1879 article by a French surgeon that theorized the existence of an additional ligament located on the front part of the knee, the doctors began dissecting numerous cadavers to track it down. Their search uncovered a tiny band of connective tissue they’ve named the anterolateral ligament, or ALL for short.

Despite having surgery and rehabilitation, a small percentage of patients with ACL-repaired knees continue to experience so-called “pivot shift,” or incidences when their knee “gives way” during activity. When ACL surgery is unsuccessful, patients sometimes endure chronic joint pain and knee instability. Fixing the ALL could solve the problem.

Dr. Scott Rodeo, co-chief of the Sports Medicine Service at Hospital for Special Surgery, in New York City, and associate team physician for the NY Giants, said he’d like to think the ALL is more of a rediscovery than an outright new discovery.

“We’ve known for years that a thickening around the area where the ALL is located has a role in knee stability,” he said. “While I don’t think this is necessarily a breakthrough, I think it’s a good reminder that we need to refocus some attention on ACLs that don’t respond well to surgery.”

This story originally appeared at abcnews.go.com.

NPR.org—November 7, 2013

There is an overlooked ligament in the knee. And it might be important for keeping your knee from twisting and turning, especially after an injury to the anterior cruciate ligament, or ACL.

Dr. Johan Bellemans and his team at the University Hospital Leuven described the ligament a few months ago in the Journal of Anatomy. They named it the anterolateral ligament, or ALL, and they offered the first clear data on what it's function is.

"It's eye-opening and provocative work," says Scott Rodeo, MD, co-chief of the Sports Medicine Service at Hospital for Special Surgery in New York City. He wasn't involved in the study, but he saw Bellemans' team present the work at a conference.

"We've known for years that there was a hardened, fibrous tissue in this location," he tells Shots. "And that this area of tissue plays some role. So it's not such a dramatic discovery but kind of a rediscovery — or a refocusing of attention."

Damage to the ALL may be one reason why some people don't bounce back after ACL surgery. About 9 in 10 people who have their ACL repaired can return to sports with no problems at all, Rodeo says. But for some, the knee still isn't quite right. It buckles abnormally or gives way during sports.

"The ALL may have a role in a small percentage of patients with persistent problems after the reconstruction of their ACL," Rodeo says. "We need to learn more about its function and pay more attention to it."

Read the full story at NPR.org.