Knee injuries are very common and are in the top three diagnoses that are seen in a sports medicine practice. The anterior cruciate ligament is one of the main stabilizers of the knee. It can be injured in sports which involve starting, stopping, cutting such as football, soccer and basketball. However, it also occurs on the job from stepping into a hole or jumping down from a height.
When the ACL is injured most patients will feel a "pop" in the knee and 75% will encounter immediate swelling. Patients will have very limited range of motion of the knee, difficulty putting weight on the leg and pain. Examination of the knee is difficult since the patient cannot move the knee due to swelling. X-rays are not very helpful unless there is a fracture or avulsion of a bone in the knee. MRI is the best study to determine the extent of the injury as well as to determine if there are other soft tissue or bone injuries.
The treatment for an ACL injury is either conservative or operative. Conservative care may include bracing, crutches and physical therapy. Operative treatment involves reconstructing the anterior cruciate ligament. Unless the ligament is torn with an attached piece of bone it cannot be sewn back together.
I determine whether or not to recommend conservative versus operative treatment based on the patient's activity level as well as their complaints. Over the years I have seen a few patients with a torn ACL have little to no complaints of knee instability. If their activity demands are low then I would recommend a course of physical therapy and bracing. Follow up is essential to check and see if the patient is experiencing any problems. Recent studies have shown that over the lifetime a patient who has undergone ACL surgery has a much better outcome then those who have not.
For the majority of patients I see I recommend ACL reconstruction. Over the years this surgery has become routine and often takes less than one hour. Since the ligament almost always needs to be reconstructed we have to use a substitute tissue. This is called a graft. The graft can come from the patient and is called an autograft or it can come from a cadaver which we call an allograft. Ultimately the decision is based on discussion with the surgeon and the patient. The benefit of allografts is that the patient is not using any of their own tissue which makes the surgery less invasive and debilitating. For the teenager undergoing ACL surgery autografts are preferred and provide a more reliable outcome. Those patients older I recommend an allograft, usually a tibialis anterior tendon which is from a donor's ankle. The tendon is thick and I fold it over to double it. ACL reconstruction is done arthroscopically and the patient is able to leave the hospital the same day.
Postoperatively the patient is placed in a hinged knee brace for six weeks. This is worn when the patient is ambulating. I send my patients to physical therapy right away and their activity is advanced based on their progress. Most patients can start light jogging at three months and can return to full sports in six to nine months.