Two orthopedic surgeons have told me that I need ACL surgery. The general feeling I get is that the sooner I have the operation, the more likely I’ll have a good result. But they tell me there’s no guarantee the surgery will be 100 per cent successful. Why not? Why shouldn’t I expect a good result?

You didn’t mention your age or athletic/sports participation. Most anterior cruciate ligament (ACL) tears occur in young athletes. Early repair is often suggested for ACL injuries, especially full-thickness tears in athletes. Surgery is also advised when there are other injuries in the area as well.

Mild injuries can often be successfully restored with a three to six month rehab program. Athletes must be very consistent in following their program. Compliance will help them avoid surgery and return to sports participation on time.

Many patients report satisfactory, good, or even excellent results after this surgery. There can be a few problems. For example, many patients who receive a bone-patellar tendon-bone graft have persistent knee pain when kneeling.

Degenerative joint changes are seen on X-ray in over one-third of the cases. Changes such as narrowing of the joint space and bone spurs around the joints may be more likely in older patients who are overweight.

Researchers are still trying to find out which patients are most likely to have an excellent result and who might have a poor result. If they can identify factors that point to a less than satisfactory result, patients can be given other treatment options. Or surgeons can begin to look for ways to improve the results of surgery.

Since no one can predict results with 100 per cent accuracy, no guarantees are made.