Arthroscopy of the Knee
Anterior Cruciate Ligament Reconstruction
One of the ligaments in the center of your knee, the anterior cruciate ligament (ACL), is prone to injury. The damage often occurs from a twist–losing control while skiing, falling off a ladder, contact sports–all can lead to an ACL injury. Damage to the ACL occurs when the knee is twisted beyond its normal range of motion. Patients commonly report hearing or feeling a “pop.” You may have pain, swelling, or too much “play” in the knee-or you may have none of these symptoms. You may have locking or difficulty rising from a chair or walking down stairs.
A complete tear in the ACL means that there is no remaining undamaged ligament. A partial tear may also occur and is similar to the unraveling of a rope. It is common to injure other parts of your knee when you damage your ACL (medial collateral ligament, medial meniscal tear, etc.).
The first thing you know when you injure your knee is that something is wrong. You may even be able to walk fairly well without a lot of pain, but something is still wrong. Your medical history (how the injury occurred, what your symptoms were then and what they are now) is important to figure out how the knee may have been injured. Your surgeon will evaluate the knee with several standard clinical tests to try and determine the extent of the injury. X-rays will be taken to rule out a bony problem or fracture. A magnetic resonance imaging (MRI) scan may be ordered to confirm what the examination shows.
It is not always necessary to repair the ACL when torn or partially torn. Ice and elevation controls swelling. Crutches and/or bracing rest the joint and protects from further injury. Your surgeon may then recommend physical therapy to strengthen muscles to make up for a weakened or torn ACL.
The most common treatment for ACL tears is reconstruction. This is done with the arthroscope and involves replacing the torn ACL with healthy tissue from the kneecap (ACL graft). Other injuries, such as a torn meniscus may be repaired or removed at the same time (see knee arthroscopy). In reconstruction, a piece of the kneecap, the center section of the patellar tendon, and a piece of the tibia are removed to be used as the ACL graft. This graft is placed in the knee through holes drilled with special guides to insure correct alignment. The graft is secured in the knee with metal or bio-absorbable screws that hold the graft in place until it heals (6-8 weeks). This is done while viewed through the arthroscope to minimize the size of the incisions.
ACL reconstruction can be done as an outpatient, but frequently requires an overnight stay in the hospital. Your surgeon or family doctor will check to see if you are healthy enough to have surgery and spinal block is generally recommended. You should NOT eat or drink anything after midnight the night before your procedure. When you arrive at the outpatient surgery area, you will meet the anesthesiologist who will do your block. The spinal block is a very safe and effective procedure that can be done on most patients. Advise the anesthesiologist if you have had spinal surgery, any problems with a previous block, are on blood thinners, or have any bleeding problems.
Once your block is in you will be taken to the operating room where all of the arthroscopic equipment is set up. You will be put on a special table and a pressure cuff placed on your thigh. This cuff decreases bleeding and enables your surgeon to better see inside you knee joint. Your surgeon will then test your knee to make sure you cannot feel any pain and then will make two small incisions and insert the arthroscope into the knee. If you would like, you can watch the TV screen and see what the surgeon sees or you can take a nap until the procedure is over.
After surgery your knee will be bandaged and in a brace that protect the knee and limits the motion. You will be instructed on walking with crutches and will begin light exercises to get the knee moving slowly. A continuous passive motion machine (CPM) may be used to assist in this task. The knee will remain swollen for up to 2 weeks. Your surgeon will schedule a date and time for your after surgery office visit. You will require pain medication for 3-5 days after surgery. You will need to keep your bandage and brace dry at all times.
After ACL reconstruction, your surgeon will start you on a 6-month course of supervised physical therapy. You and your therapist will be given a copy of our ACL exercise protocol (schedule). It is very important that the schedule is followed precisely to avoid overworking the ACL graft before it is ready. Wearing the ACL braces (long IROM brace first, then the low-profile DonJoy) is also very important in the protection of a healing ACL graft.
When less than 50% of your ACL is torn, your surgeon has another option for treatment. The ACL can be heated with a probe that causes the fibers to shrink and thereby get tighter and stronger. When a partial ACL tear of this type is suspected, your surgeon will recommend to inspect the ACL with the arthroscope and decide, at that time, whether shrinkage or reconstruction is the best treatment. It is difficult to be sure, from examination and scans; just how much of the ACL is torn. Recovery from shrinkage is much shorter and requires bracing for less time. Return to activity is much quicker, as well.