Belgian physicists have discovered a new ligament in the human knee, a finding that could revolutionize treatment of anterior cruciate ligament injuries, TIME reported via Science Daily.

After four years of research, Dr. Steven Claes and Professor Dr. Johan Bellemans located the ligament while trying to solve a medical mystery: Why did patients with repaired ACLs still experience "pivot shifts" in the knee?

The two scientists based their research on an 1879 article from a French surgeon, who theorized that another ligament might exist in the human knee. Claes and Bellemans used macroscopic dissection techniques on a variety of cadavers to confirm the French surgeon's hypothesis.

Their findings revealed that 97 percent of humans have an anterolateral ligament in addition to the ACL. Pivot shifts, where the joint gives during physical activity, stem from an injury to this body part, which doctors didn't even realize existed.

The ALL discovery could mean better treatment for ACL injuries in the next few years. These injuries are common in sports like basketball, football and soccer, where players frequently pivot.

The Belgian scientists are now working to find surgical techniques to remedy injury to the ALL, but the report says the results are still "several years" away.

Some of Claes and Bellemans' conclusions were recently published in the Journal of Anatomy, Science Daily reported.

The Anatomical Society called the findings "very refreshing" and "commended the researchers for reminding the medical world that, despite the emergence of advanced technology, our knowledge of the basic anatomy of the human body is not yet exhaustive."

Knee replacements are one of the most common surgeries for older people, the National Post reported. The outlet also noted that anatomy and physiotherapy textbooks will need to be written now.

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