Female Basketball Players Hindered by ACL Injury

How Does This Injury Occur?

That all depends. Unlike Ralph's experience, Sue Bird (a teammate of Ralph's at the time) tore her ACL while performing a routine basketball move.

"We were doing a 3-on-2 drill in practice. I just jump-stopped to take a shot and my knee kind of gave out. My calf went to the left and my quad went to the right. It felt like it split. I didn't hear the legendary pop that you're supposed to hear. I felt a little pain but nothing excruciating. I got up and walked off the court. I thought I would be fine, but the MRI showed I had torn my ACL."

Ralph's and Bird's ACL tears represent the two most common instances of the injury involving female athletes: violent planting of the foot during a high-speed, high-impact stop/change of direction, and a routine jump-stop that players do dozens of times in a game or practice. Most ACL injuries occur when landing from a jump, cutting, pivoting, or with sudden deceleration, essential movements in the game of basketball.

Anatomy and Function of the ACL

The ACL is the ligament in the middle of the knee that connects the thighbone (femur) to the shinbone (tibia). It is a broad, thick cord the size of a person's index finger. Along with the posterior cruciate ligament (PCL), the ACL provides the axis for knee rotation, helping keep the knee stable and protecting the thighbone from sliding forwards and backwards on the shinbone.

Rebuilding the Ruptured ACL

Ralph and Bird had the same surgical procedure to reconstruct their ACLs. A graft was taken from the patellar tendon in the injured knee and used as the new ACL. Although, in Ralph's case, since she had had her ACL repaired once before, the tendon graft was taken from the other, healthy, knee.

Both players reported stiffness immediately after surgery and spent two weeks in an immobilizer that keeps the injured leg straight. Rehab began immediately.

"You work on your range of motion a lot," said Bird. "I could straighten my leg easily, but bending was hard at first. I could get to ninety degrees, but past that, they would have to push and then it was pretty painful." Bird also works on muscle building and balance, because the muscles around the knee have wasted.

At seven weeks into her rehab, Bird had progressed very well but was at a particularly difficult point in the rehabilitation process.

"They say that between five and eight weeks the knee is at its weakest point. The graft has to build its strength, because when they first put it in, it is a tendon and now it is in the process of turning into a ligament."

Protecting the ACL

Ralph has made some adjustments to try to prevent another ACL injury such as distributing her weight more evenly on both feet when jump-stopping. Because of her body type she has taken even more precautions.

"I worked on turning my feet outward and being conscious of it," she explains. "I also worked on keeping my knees faced out, how to jump and land, how to collapse if I fall, how to position my leg if people are about to fall on it."

The importance of the ACL to an athlete's knee stability is undeniable. So, what is it about women that makes them more prone to injure their ACL? At this point we don't know for certain. But here's what the sports medicine experts are thinking:

• Women have looser joints than men. Estrogens (natural and in birth control pills) contribute to this looseness.
• Women tend to have smaller ACLs than do men, and this may make tearing more likely as the intensity of women’s play rises to equal that of men’s.
• Women at risk for ACL injury tend to perform sports-specific movements such as planting and crouching in ways (back flexion, hips straight or extended, knees turned inwards) that make subsequent ACL injury more likely.
• Women may have less effective “core stability” control because of relatively less well-developed abdominal and lower back muscles.

Applying the Theories to Ralph and Bird

Female hormones affect the ligamentous tissue. A study by the University of Michigan and the Cincinnati Sports Medicine Clinic found that female athletes are more prone to ACL tears during the ovulatory phase of the menstrual cycle (typically days 10-14) when their levels of estrogen and relaxin (another hormone) are highest. Researchers hypothesize that these hormones may significantly affect tendons and ligaments.

Wider pelvic structure of women puts added pressure on the ACL. Ralph would appear to be a strong case for this widely held theory. Because the hips of women are wider than in men, their anatomical alignment is different. The angle at which the femur meets the tibia is sharper in women. At this point, researchers have not established a conclusive relationship between this angle and ACL injuries.

Women's looser joints may be the problem. Studies have suggested that since women overall have looser joints than men, they are more prone to ACL tears. Sue Bird's tight joints and several other studies suggest that joint laxity and ACL injury may not be related.

Women run too upright. This intriguing idea will have to be followed more closely. A University of North Carolina School of Medicine study concluded female athletes perform running, crosscutting, and side-cutting maneuvers in a more upright posture. They were less likely to bend at the knee and hips than their male counterparts.

Though further research is needed, Dr. Robert Leach, editor of the American Journal of Sports Medicine, explains what is known to date.

"The muscle strength around the knee and the limb response to the new demands of the women's game are making this injury more evident among females."