Q: I tore my ACL. Is surgery inevitable?

A: The anterior cruciate ligament (ACL) is a band of tissue that runs through the middle of the knee joint and keeps the shinbone from sliding forward past the thighbone. The ACL can tear during a sudden or awkward twist, turn or stop. More often than not, it's these noncontact injuries that injure an ACL.

Women are more vulnerable to ACL injuries than men, but it's not clear why. The anatomy of a woman's knee is different from a man's. When a woman pivots or stops suddenly while running, her knee is bent more inward than a man's. This puts more strain on the ACL.

Obesity and weakness of the hamstring muscles in the back of the thigh also appear to be associated with ACL injury.

For elite athletes, the treatment is fairly clear: reconstructive surgery to replace the ACL, plus intense physical therapy. The sports that most often are associated with ACL injuries are skiing, football and gymnastics.

I'm assuming that you're a recreational athlete. If so, the answer is often different. If your ACL is only partially torn, then forgoing surgery in favor of rehabilitation through physical therapy is worth considering. Surgery could still be an option down the road.

Physical therapy can strengthen the muscles around your knee enough so they compensate for the nonworking ACL. A knee brace could protect your ACL during an occasional tennis or soccer game.

Without surgery, you should recover enough to be active again within two or three months. That's compared with about six months for surgery patients. On the flip side, surgery will make your joint more stable than physical therapy rehab alone.

Once your ACL has healed, these exercises can help prevent re-injury:

-âStrengthen the muscles around the knee. Keeping your quadriceps (front of the thigh) and hamstring muscles strong and flexible will make the knee more stable. One exercise that strengthens the quads and hamstrings is a walking lunge. This involves taking a large step forward and dropping the back knee down toward the floor, keeping your front knee over your ankle.

-âKeep your hip muscles strong. One-legged squats - knee bends done while standing on one leg - are a great way to strengthen the hips, quadriceps and hamstrings and to improve your balance. When you do a one-legged squat, bend your knee slowly so it ends up just over your toes.

(I've put an illustration of the correct way to perform a walking lunge and one-legged squat on my website.)

You and your doctor will need to carefully consider the extent of your injury, your age, your activities and other factors when determining the best treatment for your ACL injury.
