The anterior cruciate ligament is a frequently injured structure. This ligament can be injured during activities of daily living or more often during sporting or work type events. Injury can result from either contact or non-contact type injuries. Often the injured person will have felt a pop in his or her knee and will have developed swelling either immediately or later that day. Occasionally the injured person will have been able to continue his activities immediately after the injury prior to the onset of swelling.
Ligaments are like ropes that hold the bones together. When a ligament is torn it allows one bone to slide abnormally on another. There are generally considered to be four major ligaments in the knee. They are the anterior cruciate ligament (ACL), the posterior cruciate ligament (PCL), the medial collateral ligament (MCL), and the lateral collateral ligament (LCL). When more than one ligament is torn at one time it increases the amount of abnormal movement between the bones.
When an individual has an increased amount of movement between the bones (due to a torn ligament or ligaments) he or she can experience sudden and unpredictable giving way of the knee or primarily knee pain. When a knee is abnormally loose there also is an increased incidence of torn cartilage (menisci). The meniscus acts like a spacer in between the tibia (shin bone) and the femur (thigh bone). The purpose of the meniscus is to act both as a shock absorber and as a secondary stabilizer in the presence of a knee with anterior cruciate ligament deficiency. Preservation of healthy menisci is very important to minimize the chance of developing degenerative arthritis in the injured knee.
Unfortunately it's not rare to also injure menisci or other ligaments at the time of anterior cruciate ligament injury. Some ligaments such as the MCL and LCL usually heal well without surgical treatment. Other structures such as the menisci heal less predictably. When meniscal tears occur in association with anterior cruciate ligament tears they may be either of a repairable or a non-repairable type depending on the size and type of tear present. At times meniscal tears may heal spontaneously over a period of three to four months. Signs of meniscal tears include pain along the medial or lateral joint lines, persistent swelling more than two weeks after injury and the sensation of a catching or clicking in the knee which may be associated with the inability to straighten the knee completely. In a knee with an anterior cruciate ligament tear arthroscopic surgery may be necessary to evaluate and treat associated meniscal tears if the swelling and motion does not steadily improve over the first several weeks to a month after injury.
At the time of arthroscopic examination of the knee if a repairable meniscal tear is discovered I believe it should be repaired. The rate of successful meniscal repair is approximately 80-90%. In most cases this repair may be accomplished arthroscopically with only a very small incision necessary. In a knee with a torn ACL, reconstruction of the anterior cruciate ligament significantly improves the success of meniscal repair and does not significantly delay return to full function more than it would be delayed by the meniscal repair itself. Therefore, if a repairable meniscus tear is found I also recommend concomitant anterior cruciate ligament reconstruction. If a large portion of the meniscus is torn is such a way that repair is not possible or if most of the meniscus has already been removed, meniscus transplantation may be considered but this is rarely necessary. This may be done at the time of ACL reconstruction or later depending on the clinical situation.
Why Repair or Reconstruct the Anterior Cruciate Ligament?
Many individuals can function very well with an anterior cruciate ligament deficient knee. Studies suggest that at least 60% of individuals with such an injury can function quite well for their normal activities of daily living with no or minimal symptoms of pain or giving way. Some individuals can return to athletics after a period of appropriate rehabilitation. At times knee braces can be beneficial to patients who have anterior cruciate deficient knees. Braces are not however necessary in all instances for patients to return to athletic activities with ACL deficient knees.
Activities that are most limited in patients with ACL deficient knees include running, jumping and cutting sports. If an individual wishes to return to these sports with an anterior cruciate deficient knee there is increased risk of knee injury possibly including meniscal damage. It is suspected but not proven that anterior cruciate deficient knees may have a higher rate of degenerative arthritis many years later. This is perhaps even more likely if an anterior cruciate deficient knee sustains meniscal tears that require removal of part or all of the meniscus.
Who Should Have ACL Reconstruction?
Individuals who wish to return to the highest levels of athletic activity after an injury to the anterior cruciate ligament may wish to consider ACL reconstruction. Unfortunately, even in the immediate post an anterior cruciate ligament effectively. This was tried for many years but results were disappointing. At the present time the ligament may be repaired only if it is torn directly from either the femoral or tibial attachment sites. These injuries are rare and can often be detected on initial post-injury x-rays.
We commonly use quadriceps and hamstring tendons for ACL reconstruction. We and many other surgeons have found that patients have less pain and a quicker recovery with these types of ACL reconstructions. The quadriceps tendon is a very strong graft, avoids pain and complications related to patellar tendon graft use and also avoids possibly weakening the hamstrings which help protect the ACL. Long-term results of quadriceps tendon for ACL reconstruction have been generally equivalent or better than other techniques. Other graft types such as patellar tendon, hamstring or allograft (cadaver) tissues are used less commonly but also have excellent results. When tissue is "borrowed" from another part of the knee, over a period of time the borrowed tendon does not generally result in any major loss of strength or knee function assuming a dedicated rehabilitation program. Overall the most important thing is not the where the graft came from but rather where it is placed (precisely), how it is fixed (securely) and how rehabilitation is done (diligently).
The results of reconstruction are generally very good and restore stability and excellent function in approximately of 90% of patients. Possible complications include chronic knee pain, limited motion, recurrent instability or even the need for further surgery. Each of these complications is unusual and we will work with you closely both in the preoperative and postoperative periods to avoid each of these complications should you elect to have an anterior cruciate ligament reconstruction. Very often there is an area on the front of the knee that remains numb adjacent to the incision. This numbness can be permanent. After ligament reconstruction most patients are able to return to their full desired sporting activities without need for knee bracing and with good confidence in their reconstructed knee.
What Exactly is Involved with ACL Surgery?
If you continue to have pain, swelling and limited motion in your knee several weeks to a month after your injury arthroscopic surgery to evaluate possible meniscal damage or torn fragments caught in your knee may be suggested. If a torn fragment of the ACL or a non-repairable meniscal tear is found and if you prefer to proceed without early anterior cruciate ligament reconstruction surgery can be performed on an outpatient basis to remove the torn tissue (meniscus or ligament) and to evaluate the rest of your joint. This often allows return to work or school activities within several days. (If you choose such a treatment plan and develop symptoms from your knee instability, reconstruction can be performed at a later date with results similar to those knees that are reconstructed in the first four to six weeks after injury.) After arthroscopic removal of torn tissue you will generally be allowed to walk on your injured leg as tolerated after surgery. The length of time until you return to full activities depends on the extent of your associated injuries and your dedication to postoperative rehabilitation.
Most ACL reconstructions are done as outpatient surgery. You will have a knee brace holding your knee straight after surgery and will use crutches for approximately two to four weeks. You will also generally use an ice/compression device immediately after your surgery. We will carefully instruct you in an exercise program beginning the day after surgery. This program will stress maintaining full extension of your knee and in beginning to recover the strength immediately after surgery. Generally patients are walking comfortably for activities of daily living within four to six weeks after surgery without crutches. The healing process for an ACL-reconstructed knee requires careful compliance and excellent motivation from the patient. The tendon graft tissue which is placed during the ACL reconstruction requires one year or more to fully mature and to be able to handle the loads that full return to activity may impose. Prior to this time the knee often feels nearly normal and it is very important for the patient to consciously avoid activities which might put the knee at risk. Some surgeons allow return to vigorous activity by 3-4 months. If this is considered, the patient may have increased risk of failure. However, sometimes early return to sport and work is possible.
Each time we see you after surgery we will instruct you in the progression of your exercises. If necessary, referral to a physical therapist may be suggested. In most cases such therapists are available in a location convenient to each patients home. Full return of strength to a leg after such surgery may take four to six months. After ACL reconstruction surgery patients will usually be able to return to office type jobs or to class within one week after surgery.
If you have any questions regarding your injury and/or the treatment options you face please do not hesitate to discuss this with me. This is a very important decision for you and I urge you to understand both the facts regarding your condition and the impact it will have on your life after your treatment. If you do elect to have me do your surgery, we will work closely with you to achieve the best results possible.