Most sports enthusiasts have heard of the ACL (anterior cruciate ligament). ACL injuries by big name athletes, like NFL quarterback Robert Griffin III and NBA point guard Derrick Rose, keep the ligament in the news, but even with increased exposure and advancements in medical knowledge, not all is completely understood about the human body. Believe it or not, ligaments are still being discovered and studied.
A research article released in October 2013 by two Belgium surgeons described a new ligament of the knee, known as the anterior lateral ligament (ALL). This article better clarified the anatomy of the ligament, which was first described by a French surgeon in 1879.
What Is the ALL?
The ALL runs from the thigh bone to the shin bone, located on the outside of the knee joint. The ligament’s function is believed to prevent the knee from rotating inward with flexion of the knee.
What Is the Significance of the Discovery of the ALL?
The discovery of the ALL will have the largest impact on patients following ACL injuries and total knee replacements. It has been estimated that in about 80 percent of ACL injuries the ALL also is injured.
During knee replacements, surgical exposure while inserting the knee prosthesis also may damage the ligament. Following surgery, many patients describe their knee “giving way” while walking, running or stair climbing, which is speculated to be caused by an ALL injury.
Research is ongoing for surgical and medical management of injuries to this ligament.
How Will the Discovery of the ALL Impact Rehab?
Following ACL reconstruction or knee replacement surgery, a physical therapist  will evaluate the patient for strength, balance, flexibility and range of motion impairments. The evaluation will encompass the entire lower extremity and not just the knee. It is important to strengthen the hips as well as the knee in order to better control rotational movements while walking or participating in sports.
As a result of the discovery of the ALL, more emphasis should be placed on regaining proper rotational movement at the knee joint and strengthening the muscles that control this motion in order to prevent re-injury. A physical therapist will prescribe exercises and perform manual therapy techniques to correct these impairments in order to return the patient to his or her prior level of function.