Knee ligament discovery could bring new twist to ACL treatment

For sports professionals, a torn anterior cruciate ligament - or ACL - can mean the end of a career.

 

Even after surgery and lengthy rehabilition, there are no guarantees of recovery, although knee specialist Professor Johan Bellemans has always believed there is room for improvement.

 

"When somebody tears his ACL and he undergoes surgery we know that there are 10 percent to 20 percent of patients who continue to have some form of instability. That is unlogical because we fixed what was broken, therefore we were convinced there had to be another structure which was damaged also but which remained unrepaired so far," Bellemans said.

 

Now, Bellamans and University of Leuven colleague Dr Steven Claes say they've identified that structure, based on detailed examinations of more than forty donor knees.

 

It's a previously unknown fibrous band among the four ligaments linking the femur and tibia.

 

They've named it the anterolateral ligement - ALL for short, and say understanding it could alter treatment of knee ligament injuries.

 

Dr Claes says that while the ACL is located deep inside the knee's centre, the ALL runs along its outer side.

 

"While the ACL is controlling AP instability meaning from front to back, this ligament is controlling rotation of the knee, this movement. What we noticed is that in many ACL injured subjects, that both ligaments seemed to be disrupted. So you can expect that if you only treat one of this injuries that some laxity and some instability, especially this rotational laxity will persist after an operation for instance," Claes said.

 

Athletes suffer knee ligament injuries when changing direction or stopping abruptly. They range from mild to severe tears and ruptures that can cause lasting instability.

 

Claes believes the newly-discovered ligament could play an important protective role in restraining excessive knee rotation as athletes pivot.

 

But some experts, like leading soccer surgeon Marc Martens believe the findings, although interesting, have been overblown.

 

"It's more than just this ALL, it's more than just this little fibre band. We should realise that it's more. All these structures on the lateral side, including the ALL are damaged and stretched," Martens said.

 

Claes and Bellemans published their research in the Journal of Anatomy.

 

The pair say that despite advanced surgical techniques, up to half of athletes cannot perform at the same level as before their injury.

 

They're convinced that the ALL ligament holds the key to improving outcomes - and extending careers - for athletes world-wide.  — Reuters