Understanding ACL Tears, Repairs and Injury Prevention

When the anterior cruciate ligament in my left knee tore while playing soccer, I knew it was an injury like none I had had before. The entire knee joint seemed to disassemble. I went down in a heap on an indoor soccer field. I was 45 years old. I've played sports all my life and had my share of ankle and knee sprains, but this was different.

I'd gotten home that evening with much difficulty, driving with one foot, crying in fear and grief over what I knew to be a major injury. After hobbling in from the garage, I lay crookedly on the couch and told my wife, "Well, I really did it this time."

It took a week for the swelling to go down. Then a visit to the orthopedist told me the ugly truth. I'd torn the ACL. That meant my knee would not function well in sports that required any sort of ballistic (sideways and stopping) movement.

Six months later I decided to have surgery. I tried living without the ACL but decided I still wanted to play sports I loved like tennis, basketball and soccer. Once I elected to have ACL surgery, the orthopedist had me enroll in a "pre-physical therapy" program to strengthen the knee joint, especially the quadriceps, as much as possible. That way you have some semblance of holdover strength when you come out of surgical recovery.

The surgery went smoothly. I chose to have a cadaver part installed to replace my broken ACL because recovery time was quicker. The other, more involved option was to have a slice of my patellar tendon (the long tendon under the front side of the kneecap) used as a new ACL. Using your own tendons, it turns out, is considered to be a generally superior option in many cases. First, the tissue is live and healthy. Second, your own tissue is less likely to cause a reaction in your body. There is also some risk of infection from the cadaver option.

The first week after the surgery is generally a difficult time. I spent it hooked up to a machine that very slowly bends the knee and lets it relax. This is to combat the tendency of the joint to go stiff after surgery, and to fight the inevitable swelling. Even with arthroscopic techniques, ACL repairs are traumatic to the joint. Orthopedic surgeons balloon the knee with fluid, then make three arthroscopic (holes) insertions to access the inner knee where the replacement tendon material is stapled onto bones inside the knee. For weeks after my surgery it was necessary to wear a compression sock on my left leg and still my foot swelled from the rigors of daily life at a desk and commuting. The wounds "wept" considerably (which was gross) and my foot stung like a thousand bees had gotten inside my shoes. So the recovery process was not a piece of cake. But in retrospect it did not last that long.

You can read more about the surgery and recovery process on a number of web sites about ACL reconstruction. Many such sites include helpful diagrams of how your ACL attaches within the knee. It can be helpful for any person to study these images to better understand ACL repair and maintenance. One particularly helpful site, http://www.arthroscopy.com/sp05018.htm, offers complete diagrams of how the knee stability system works. Having a mental image of the structure of the knee and role of the ACL can help you visualize the purpose and benefit of the work required to rehabilitate your knee.

Once the swelling from surgery goes down, you begin immediate work to develop and maintain range of motion in the joint. Physical therapy often begins a week or two after surgery. The physical therapist will determine what level of strength you have sustained and begin building up muscle tone in muscles on the front and back of your knee. Through supervised rehabilitation, some athletes have been able to return to competitive sports in three months or so. The most notable success story is Shannon McMillan, a women's national team soccer player who tore her ACL yet made it back to play in the World Cup that same year.

She is the exception rather than the rule, however. Most athletes require a year or more to get back to playing the sport of their choice.

I was determined to get back to competitive shape, yet after two full months of physical therapy the knee was far from stable. The first whole month I was required to wear a stabilizing brace even while walking. This was inconvenient and I dumbly shed the brace while attending a soccer tournament with my daughter. I did not hurt my knee, but I did strain my achilles tendon on the opposing foot in trying to compensate for weakness in the knee. You should always follow the doctors orders.

For the next six months I went to the gym to work out three days a week on my own. I followed the instructions of the physical therapists and did knee exercises that included weightlifting, bounding and lateral floor workouts to rebuild stability. The same workouts designed to rehabilitate a repaired ACL are useful to athletes seeking to prevent an ACL injury. Strengthening the knee is a worthwhile investment of time for any athlete. Many sports medicine clinics now offer ACL injury prevention clinics. These are helpful particularly to young women who suffer a much greater percentage of ACL tears than any other athlete. Clinical studies suggest this high incidence of injury is due to a variety of factors including the pelvic structure and thigh bone angle in young women. These angles contribute to torque on the knee that can result in strain on the ACL.

I heard football commentator and 1985 Super Bowl Champion Chicago Bears player Tom Thayer say that he believes ACL tears are a "fatigue" injury. By that he means that a knee joint that is being supported by tired muscles is more likely to collapse under impact or ballistic pressure.

But having seen players like soccer star Chris Armas tear their ACL just by pivoting on the field, the fatigue theory of ACL injury may be only partially correct.

The truly inexplicable fact about ACL tears is that they can occur in athletes suddenly and with no apparent explanation at all. An athlete may play for years and make thousands of turns and cuts on the field with no risk to the ACL. Then one day, the wrong cut or turn causes the wrong kind of strain and "pop!" it goes.

That's why it supposedly pays for an athlete to engage in consistent strength training to cut the odds for tearing the ACL or other ligaments. Even with that work, bad fortune can enter the picture. The top scholars in the field of orthopedics still cannot effectively predict who is at the most risk for an ACL injury or tear.

After a full year of rehabilitation I returned, gingerly, to kicking a soccer ball around the indoor field. It felt risky, but it also felt good to know the hard work I'd put in was paying off. I'd returned to running about six months into recovery. I started riding a road bike as well. After 14 months I did return to playing soccer as planned. That comeback lasted about two years when circumstances combined to put me at risk all over again. I had missed a couple weeks of strength training due to the grossly combined effects of a tick bite and poison ivy I'd picked up during a May bird census. When my outdoor soccer team called saying they need players desperately I agreed to join them and wound up playing on a rain-slicked field on a hot day in May. I had just received the ball in scoring position toward the end of a tiring second half when an opposing player rammed into the side of my left knee in an attempt to stop the shot on goal. I felt a click and fell to the ground. "It happens," the physical therapist at the gym told me. "About 30% of athletes who have an ACL repair tear it again."

I was too depressed to repair the ACL a second time around. Fixing a torn ACL the second time is called a "revision." I call it a pain in the neck, so I haven't done it. You can do many things in life without your ACL! I even know a physical therapist who still plays all his favorite sports without an ACL. He just wears his brace. I figure he knows his absolute risks better than me. But maybe not. Maybe he's just got more guts...

I've moved on from ballistic sports and increased my commitment to cycling to get that competitive jazz I miss from playing soccer and basketball.

Maybe I'll do the "revision" thing some day. For now, I do my physical therapy routine and enjoy the running and activities I can do. It's a great triumph to make a comeback from a torn ACL. I would recommend it to anyone. Just make sure you stick with the "good work" required to keep it from tearing again.