1. A complete ACL tear cannot be repaired. It has to be replaced or reconstructed (with one exception).
When the ACL tears, you can't repair it just by stitching it up. It would be like trying to sew up the ends of two mops together. The only exception is in pediatric patients. Sometimes their ligament doesn't tear, but pulls a chip of bone off of the tibia instead. In that case, the ligament itself is intact, and sometimes the surgeon can go repair the bone chip back to where it was. This can restore the proper tension of the ligament without replacing it.
2. I've completely torn my ACL. Do I need surgery?
The ACL is critical in allowing the knee to do cutting, pivoting, twisting activities and sports. It is not as crucial for walking in a straight line and sitting at a desk. A successful ACL reconstruction gives you not necessarily a "normal" knee, but a "stable" knee. Remember, each time the knee gives out, there is a risk of further damage to the meniscus and cartilage. With further injury to the joint, you can develop early arthritis. Because of this, just about every young (<35) person should have surgery. Older folks who are still physically active or who experience knee instability will probably want to have surgery as well. However, some elderly people, who lead a more sedentary lifestyle and don't have "giving out" symptoms, may choose to forego surgery.
3. What does the surgery involve?
Surgery is performed arthroscopically and is usually outpatient (same day) surgery. The goal is to provide a way for your body's cells to grow a new ACL from the femur to the tibia, but they can't jump the gap by themselves. The graft acts as a sidewalk or scaffold for the new blood vessels and cells to grow onto. The process of forming a new ligament, or ligamentization, continues probably beyond the first year. Through small skin incisions, the ACL graft is brought into the knee and placed into position, under the proper tension. There are many ways to secure the graft, including screws, pins, sutures, washers or buttons. You are usually on crutches with a knee brace for a variable amount of time. The surgeon may opt to place you on a continuous passive motion (CPM) machine. This may help you gain some early motion, but studies have not shown any long-term difference.
4. What are my graft options?
There are many graft choices. The main options are autografts (own tissue) versus allografts (cadaver tissue). The main autografts used are either a strip of your patellar tendon (between your kneecap and shin bone) or your hamstring tendons (back of your thigh). Allografts are becoming more popular as sterilization techniques and availability have improved. There is a small risk of disease transmission and delayed graft healing, but some studies have shown equivalent results of autografts and allografts at the five-year mark.
5. When can I play again?
Usually, it takes six to twelve months to return to sports. Generally, you will want to have full motion and full strength back before returning to high-level activities. Physical therapy is very important after surgery to help reactivate and rebuild the muscles and to put you through sports-specific drills before going back to the real thing.
