By Dr. Michael Gruber
Is it the ACL? That's the question on everyone's mind as we evaluate a college bound athlete with a knee injury. The story is all too common: a noncontact injury after a leap or quick stop, a "pop" and a giving way, followed by pain and swelling in the knee and inability to return to play. The questions continue. What is the ACL? How can you be sure it's torn? What do we do now? Is surgery required to repair it? How do you fix it? When do we fix it? More and more often, the parents are asking, "Why did this happen to her?"
In my practice, the athlete with an ACL (anterior cruciate ligament) injury is more likely to be a 17 year old female soccer player than a 250 pound football player. In fact, among basketball and soccer players, women are 5 to 8 times more likely to sustain an ACL tear than a male player. There are several factors that create this disparity, including a difference in the anatomy of the male and female knee, strength and flexibility differences, and hormonal issues. In general, women are more "knock-kneed", and they tend to have stronger quadriceps muscles in relation to their hamstrings. There are also the obvious hormonal differences and the cyclic variation, differences in tissue strength and flexibility, and functional differences in technique and muscle function between the sexes in activities such as jumping and landing. "OK, so there are some of the reasons it happens," says her father," but, are you sure?"
The diagnosis is made based on patient history, physical exam, and diagnostic imaging. The ACL is one of the four major ligaments of the knee; it is in the middle of the knee and prevents the tibia (leg bone) from moving forward in relation to femur (thigh bone). When the anterior cruciate ligament tears, it allows excessive motion in the knee that can usually be detected on physical exam. Often, an MRI will be obtained to confirm the diagnosis and to look for additional injury such as meniscal (soft cartilage cushion) tears.
If a complete ACL tear is found in a young athlete, it requires surgery to repair it. The ligament cannot heal itself. It is helpful to think of the ACL as a rope under tension. If it snaps in the middle, you are left with torn ends of rope that cannot be repaired and must be replaced with a new rope. Like the rope, the ACL is replaced, not repaired. In the young athlete, a hamstring tendon or a patellar tendon graft is used to replace the torn ACL. Surgical repair is scheduled when the injury has "quieted down" and good motion has returned. The surgery is done with minimally invasive arthroscopic techniques as an outpatient or with a one night stay in the hospital. Most patients are walking with crutches the next day and are back to school or work within a few days.
Full recovery, however, takes time. The body must heal and strengthen the newly created ligament. Physical therapy is essential in returning strength and function. Return to play usually occurs in 5 or 6 months if all the goals of therapy have been met. I tell my patients that I do the installation, but they have to "get the motor running".
Another obvious question is how do we keep this from happening? There has been some success with programs developed in the hope of preventing ACL tears. Most of the research is aimed at women and addresses the issues with strength and technique previously mentioned. The PEP program, developed in Division I women's soccer, is excellent and should be embraced by club and high school soccer teams.