ACL RECONSTRUCTION

The Anterior Cruciate Ligament (ACL) is one of the most important ligaments in the knee. It runs from the lower leg bone (tibia) to the thigh bone (femur) at the knee. It acts to prevent excessive forward movement of the tibia in relation to the femur and is also essential in controlling rotation of these two bones.

The ACL is often injured by non-contact means such as indirect movements like cutting, landing, twisting or even landing motions. For instance an athlete who suddenly begins to slow down whilst running and then initiates a sharp cutting motion or when a skier catches their ski in the snow causing a rotational force at the knee.

When the injury occurs the individual will feel sudden, sharp and severe knee pain. They may possibly hear or feel a “popping” sensation in their knee. Patients will have a difficult time bearing weight on the injured leg because of an unstable “giving out” sensation in the knee. Usually within the first few hours after the injury, the knee will become significantly swollen and the range of motion will typically decrease due to the limiting effects of pain and swelling. ACL injuries are not always sports related and often a vehicle collision will cause disruption to the ACL.

Will an ACL injury require surgery?

This will depend upon the extent of the injury. An accurate diagnosis is key to initiating a treatment plan and will involve a scan (usually MRI) to achieve this. The diagnosis will classify the injury into one of three grades (see below).

A completely torn ACL will never heal back to it pre-injury “normal” state even after nonsurgical treatment such as rehabilitation and physical therapy. It is very difficult for the ligament to resume a normal length and function when it is completely torn. In addition, even with a partially torn ligament, the mechanical function of the knee may be altered after an ACL tear such that the normal mechanics of motion of the knee are altered.

Types

ACL injuries can be classified by the amount of damage to the ligament (partial or complete disruption). Injury to the ACL is usually a complete disruption, classifying it as a Grade III complete tear.

Grade I Sprain - There is some stretching and micro-tearing of the ligament. The ligament is intact. The joint remains stable. These injuries rarely require surgery.

Grade II Sprain (Partial Disruption) - There is some tearing and separation of the ligament fibers. The ligament is partially disrupted. The joint is moderately unstable. Depending on the activity level of the patient and the degree of instability, these tears may or may not require surgery.

Grade III Sprain (Complete Disruption) - There is total rupture of the ligament fibers. The ligament is completely disrupted. The joint is unstable. Surgery is usually recommended in young or athletic persons who engage in cutting or pivoting sports.

Additional Injury

Additionally, injury can be classified by the presence or absence of associated damage to other structures in the knee (isolated or combined). Combined injuries may involve damage to the menisci, stabilizing collateral ligaments, or other knee structures.

Meniscus - The medial and lateral menisci are “cushions” between the tibia and femur that act as a shock absorber and distribute stresses placed on the knee joint. Additionally, this structure helps stabilize the knee. A meniscus tear typically occurs with twisting motions such as pivoting.

PCL - The posterior cruciate ligament “crosses” behind the ACL and restrains the tibia from moving backwards (posterior) on the femur. Traumatically, this ligament is commonly injured by striking the upper tibia, causing the tibia to move backwards, thereby stretching or tearing the PCL. An example of this would be striking the upper tibia on the dashboard during an automobile accident. In athletics, a PCL will tear during a hyperextension or extreme hyperflexion injury.

MCL - The medial collateral ligament provides stability to the inside aspect of the knee. This ligament is commonly injured when a medially (inward) directed force is applied to the outside of the knee, forcing the knee to twist in and the foot to twist out. Injury to this structure is common, but if it is an isolated partial disruption injury then it can typically be treated with physical therapy and bracing.

LCL - The lateral collateral ligament imparts stability to the outside aspect of the knee. Isolated LCL injuries are infrequent, but when injured it is commonly due a lateral (outside) force applied to the inside of the knee.

It is not uncommon to hear the term “unhappy triad” associated with an ACL injury. This describes an ACL injury associated with a concomitant MCL injury and medial meniscus tear. This triad usually occurs when the ACL has been torn for a long time (‘chronic tear’). It is more common to tear the lateral (outside) meniscus after an ‘acute’ ACL tear.

Diagnosis

The diagnosis of ACL injuries can usually be accurately diagnosed by clinical examination of the knee. A skilled examiner can usually evaluate the knee joint in a painless manner and discern if the ACL has been injured. Magnetic resonance imaging (MRI) is a painless study that will give an extraordinary amount of information in regards to the degree of injury to the ACL (partial versus complete), the location of the tear within the ligament, and if there are any associated injuries in the joint (isolated versus complex).

Surgical Options

Patients should be aware that there are principally two different grafts available for use when reconstructing the ACL. Due to the uniqueness of each knee and injury from person to person Mr Leonard will make a clinical decision on what is most appropriate for you.

Hamstring Tendon Autograft

Of the five hamstring tendons which help to flex the knee it is possible to use one or two of these tendons, from the inner part of the knee to reconstruct the ACL. Hamstring autograft has also been in use for a long time and have good clinical results.

There is no bone harvested with the hamstring tendons, and therefore the harvest is easier for the patient with respect to pain. While the hamstring tendons used are technically stronger than the BPTB construct, the methods to fix the soft tissue graft into the sockets is generally less stiff.

Patellar Tendon Autograft

The ‘bone-patellar tendon-bone’ autograft, is a widely used source for ACL reconstruction. In general, the surgeon takes the middle 1/3 of the patellar ligament that runs from the bottom of the kneecap (patella) to the front of the tibia.

This graft is ‘harvested’ with bone blocks from the patella and tibia respectively. The body heals the bony portions of the graft to bone, and the ligament between serves as the substitute ACL. Advantages of this graft include its stiffness, strength, and low re-tear rate. It is also rapidly incorporated into the patient.

How long will the surgery take?

The procedure takes approximately 1 to 2 hours to complete. After the procedure, the patient can expect to spend 1 or 2 hours in the recovery room and anticipate going home on the same day of surgery.

Pain Management

The recovery of comfort and function following an arthroscopic ACL reconstruction continues over a few months. Initially, the knee must be protected with a postoperative brace, to prevent overuse or stressing the repair while the knee heals.

Additionally, a very strict rehabilitation program will be initiated to provide the most favourable opportunity to heal without complications. Ironically, many patients who undergo this procedure will feel very comfortable long before the definitive healing has taken place, so strict adherence to the postoperative activity restrictions is critical.

Immediately postoperatively, the patient is given strong medications to help with the discomfort of swelling and the work of the surgery. Patients are discharged home with a prescription for oral pain medications.

Hospital stay

Most patients do not require an overnight stay at the hospital after an ACL reconstruction. Generally, a person will spend one to two hours in the recovery room until the anesthetic medication has worn off.

Post-Surgery

ACL reconstruction is usually very effective at eliminating instability and restoring comfort and function to the knee of a well-motivated patient. The greatest benefits are often the ability to perform the usual activities of daily living and participating in sports or demanding activities without the fear of giving way, locking, or pain.

As long as the knee is cared for properly and subsequent traumatic injuries are avoided, the benefits of the surgery should be permanent.

Recovery and rehabilitation in the hospital

The first two weeks after an arthroscopic ACL reconstruction are dedicated to controlling pain and inflammation, and resting. The knee is frequently swollen for a few days following surgery. Also, the incisions will “weep” fluid for a couple of days postoperatively, and the dressing can become damp.

In order to control pain and inflammation it is advised to use a Cryocuff or ice pack for 20 minutes every hour until your first post-operative visit, then as needed for pain relief. In addition, compression with an ace wrap that is not wrapped too tightly or thickly will provide relief. Finally, elevating the operative leg above the patient’s heart as much as possible for the first 3 to 4 days will help with swelling. It is strongly advised to elevate the leg with a pillow under the calf or foot, NOT under the knee.

For the first 2 weeks, a home program of rest and gentle range of motion and muscle control exercises are recommended. Typically at 14 days postoperatively a prescription for outpatient physical therapy will be provided and the progressive return to normal function will begin.

Showering

Generally, the patient can shower a day or two postoperative day as long as the incisions are no longer draining. The area should be protected with plastic wrap and tape and should not be soaked in water.

The patient should keep the incisions as dry as possible at all times until the sutures are removed.

Returning to ordinary daily activities

In general, patients are able to perform gentle activities of daily living starting 2 or 3 weeks after surgery. Most persons who work at a desk job can return to work during this time. The patient is strongly encouraged to continue wearing the functional knee brace.

The patient should be able to drive a vehicle when they are no longer taking pain medications, and when they can perform the necessary functions required for driving comfortably and confidently. In general it may take longer for a person to drive if the right knee was operated on because of the increased demands of pushing the accelerator and brake pedal.

Enquire

ACL Reconstruction: About