Anterior Cruciate Ligament Injury

ACL Reconstruction

The knee is one of the most commonly injured joints in the body. It plays a part in balance, strength, speed, and agility. The knee is composed of multiple ligaments, cartilage, and bones. One of the ligaments responsible for stabilizing the knee, the anterior cruciate ligament, is also the most commonly injured ligament. Orthopedic surgeons can offer multiple treatment options based on the patient’s goals.

The Anterior Cruciate Ligament and the Knee

The knee is a joint where different bones meet, the thigh bone, the femur, meets the two shin bones, the tibia, and the fibula. The patella is a small bone that sits on the front of the knee. The ends of the thigh and shin bones are covered in cartilage, which helps the bones glide smoothly while walking.

There are several ligaments that provide the entire joint with stability. The anterior cruciate ligament, otherwise known as the ACL, is the most well-known. It prevents the shin bones from sliding forward. There is also a posterior cruciate ligament, the medial collateral ligament, and the lateral collateral ligament. They provide stability for different parts of the knee.

Causes of ACL Injury

Most people have heard of an ACL injury, often in a sports context. While it is true that most ACL injuries occur in athletic events, there are multiple mechanisms of injury. In an athlete, an ACL injury most commonly occurs while running or jumping and changing direction or pivoting that involves rotation and lateral bending of the knee. ACL injuries may also occur when the patient suffers a blow to the side of the knee. Lastly, ACL injuries can occur through high-energy impacts, like motor vehicle collisions.

People who have an ACL injury often feel a “pop”, have immediate swelling, and experience the sensation of an unstable knee. While they can often still walk, they have difficulty with other movements, like squatting or pivoting, that require more stability in the joint.

Diagnosis

When you come into the clinic, Dr. Morton will obtain an x-ray of your knee. This is to look for any other causes or injuries you may have sustained at the same time. After examination, he will evaluate if your knee feels unstable. Based on the clinical exam, we will discuss whether you need to have an MRI performed to evaluate your injury. An MRI would also be able to look for other causes of your knee pain such as another ligament injury, cartilage injury, or meniscus tear.

Treatment

Immediately after the injury, the first priority is rest, ice, compression, and elevation of the injured knee. Surgery need not happen immediately, and in fact, often occurs a few weeks to months afterward if the patient chooses surgery at all.

There are some patients who may be better suited for non-operative treatment. Choosing whether to operate depends on the extent of the injury and the patient’s activities and goals. For example, if a patient is older, less active, and still retains a reasonable amount of function with their injury, non-operative management may be the best option. Often, this involves physical rehabilitation.

Surgery involves reconstructing the ligament itself. The surgeon does this through the use of grafts, meaning that they take another tendon and fashion it into a ligament. There are a variety of graft choices. Surgeons can take a tendon from the patient or from a donor. The two most common tendon grafts are either the patellar tendon or a tendon from the hamstring. The patellar tendon has the advantages of increased strength and better fixation to the bone. However, it may cause some more knee pain if taken from the patient.

Using the hamstring causes less knee pain, can be very strong, but theoretically has slower fixation than the patellar tendon. Lastly, the surgeon can use a tendon from a donor. The advantage of the donor's tendon is simply that using a donor avoids taking a tendon from the patient. The patient then does not experience the pain associated with using their own tendon. However, a donor tendon may integrate slower than a tendon taken from a patient. There is also the risk of infections from the donor.

Often there will be other co-existing injuries. Any injury to the meniscus, cartilage or other ligaments will be addressed at the time of surgery.

All-inside ACL Reconstruction

There are multiple techniques used in ACL reconstruction. The anatomic all-inside technique is a newer technique. By placing the ACL in an anatomic position, it is less likely to fail. The all-inside technique involves using specialized instruments that only drill on the “inside of the knee” and does not drill into the hard outer shell of the bone. The all-inside technique involves less bone removal and can be done with smaller skin incisions.

Studies have shown that patients who undergo the all-inside technique have less knee pain compared to those who undergo the traditional technique. This is true as far out as 2 years postoperatively. Studies also show that the knee function scores and the joint anatomy outcomes are the same as the traditional method. After surgery, patients have to undergo a significant period of physical rehabilitation. The rehab emphasizes joint mobility and strength. In patients who are hoping to return to sports, rehab may last as long as 9 months.

Summary

The anterior cruciate ligament (ACL) is a commonly injured ligament in a joint that is vital for movement. There are nonoperative treatment options and surgical management options available. Surgery is tailored to each patient’s needs. There are multiple grafts a patient could choose from and multiple techniques a surgeon uses. The all-inside technique results in the least amount of pain while preserving the technical successes of the traditional approach. Ask Dr. Morton about your options in regards to having an ACL reconstruction surgery.

Works Cited

Connaughton, Alexander J., et al. “All-inside ACL Reconstruction: How Does It Compare to Standard ACL Reconstruction Techniques?” Journal of Orthopaedics, vol. 14, no. 2, 2017, pp. 241–246., doi:10.1016/j.jor.2017.03.002.

Grinsven, S. Van, et al. “Evidence-Based Rehabilitation Following Anterior Cruciate Ligament Reconstruction.” Knee Surgery, Sports Traumatology, Arthroscopy, vol. 18, no. 8, 2010, pp. 1128–1144., doi:10.1007/s00167-009-1027-2.

Paterno, Mark V. “Non-Operative Care of the Patient with an ACL-Deficient Knee.” Current Reviews in Musculoskeletal Medicine, vol. 10, no. 3, 2017, pp. 322–327., doi:10.1007/s12178-017-9431-6.

UpToDate, www.uptodate.com/contents/physical-examination-of-the-knee?sectionName=ANATOMY&search=acl tear&topicRef=243&anchor=H133527526&source=see_link#H133527526.

UpToDate, www.uptodate.com/contents/anterior-cruciate-ligament-injury?search=acl tear&source=search_result&selectedTitle=1~39&usage_type=default&display_rank=1#H3050020832.