What is an anterior cruciate ligament (ACL) tear?

An ACL tear is one of the most common sports injuries to the knee but can also result from a fall, collision, or accident.

Athletes who participate in sports such as football, skiing, basketball, volleyball, handball, and generally any contact sports or sports involving sudden changes of direction are prone to ACL injuries.

What are the injury mechanisms?

The anterior cruciate ligament (ACL), along with the posterior cruciate ligament, collateral ligaments, and thigh muscles, are the main stabilizers of the knee. The ACL helps control joint movement, protects the knee from hyperextension, and prevents the tibia from sliding forward relative to the femur.

An ACL tear can occur through the following mechanisms:

• During sudden changes in direction
• When abruptly stopping or decelerating
• With improper landing after a jump or fall
• Due to direct impact, often during a collision with another player

Several studies have shown that female athletes are more likely to suffer ACL tears than male athletes in the same sport. Possible contributing factors include anatomical differences in the pelvis and lower limb alignment, differences in muscle strength and neuromuscular control, greater ligament laxity, and the effect of female hormones (estrogens) on the ligaments.

Can ACL tears be prevented?

ACL tears can be largely prevented, especially in amateur athletes. Special training programs have been developed for ACL injury prevention, focusing on proper neuromuscular control of the knee. These programs include plyometric exercises, balance, strength, and stability training, and should be implemented consistently, not just during the athlete’s pre-season training.

What are the clinical symptoms of an ACL tear?

When an ACL tear occurs, the patient may feel or even hear a “pop” in the knee, followed by the sensation that the knee gives way or is unstable. This is usually accompanied by pain and swelling (hemarthrosis – blood in the joint), which becomes noticeable within the first 24 hours. A reduction in the range of motion may also occur.

Gradually, within a few weeks, the swelling usually subsides, pain decreases, and if the patient is not an athlete, they may return to daily activities without major discomfort.

However, knee instability often persists. For an athlete wishing to return to sports after the acute phase, this instability increases the risk of further injuries to the knee, such as damage to the articular cartilage or meniscal tears.

How is an ACL tear diagnosed?

Diagnosis is based on:

• A detailed history of the injury
• The mechanism of trauma
• Symptoms
• Clinical examination

The orthopedic surgeon will assess knee stability using special clinical tests.

While X-rays do not show soft tissue damage, they can reveal any associated fractures.
Definitive diagnosis is made with MRI, which can also detect any accompanying injuries.
In about half the cases of ACL tears, there are additional injuries to other knee structures such as the menisci, cartilage, or other ligaments.

What is the treatment for an ACL tear?

ΤTreatment – either conservative or surgical – depends on the individual needs of the patient, such as:

• Age
• Daily activity level
• Type of work
• Sports involvement
• Presence of associated injuries
• Degree of knee instability

An active individual or young athlete wishing to continue sports is more likely to require surgical treatment compared to someone less active (often older and not engaged in sports), who may return to normal daily life without discomfort by following a conservative treatment plan.

How is it managed conservatively?

In the acute phase, conservative treatment includes:

• Rest and partial weight-bearing using crutches
• Ice therapy
• Compression (bandaging)
• Elevation of the leg

After the acute phase, conservative management initially involves physiotherapy modalities to reduce pain and swelling. This is followed by a comprehensive rehabilitation program with strengthening and proprioception (balance) exercises, under the guidance of a specialized physiotherapist.

If the patient continues to experience a sense of instability or sustains a new injury despite completing a full rehabilitation program, then surgical intervention is recommended.

According to clinical studies, individuals with an untreated anterior cruciate ligament (ACL) rupture tend to develop knee osteoarthritis much earlier than those who have not experienced such an injury.

How is it treated surgically?

The goal of surgical reconstruction is to stabilize the knee and prevent secondary damage (meniscal tears and cartilage damage in the knee) that can be caused by ongoing instability. Furthermore, the ACL has very limited healing capacity compared to other ligaments in the knee, and once injured, it does not heal on its own.

ACL reconstruction with graft

Surgical treatment involves reconstruction (replacement), or ligamentoplasty, of the torn ACL, typically using a graft from the patient’s own body (autologous biological graft). The procedure is performed arthroscopically, without opening the knee joint, through small incisions only a few millimeters wide.

The grafts commonly used include hamstring tendons, part of the patellar tendon, or less commonly, a portion of the quadriceps tendon. In special cases, and when multiple ligament injuries are present, synthetic grafts may be used. Each graft type has its advantages and disadvantages. A thorough discussion between the patient and the orthopedic specialist will help determine the best option for each individual.

In recent years, ACL reconstruction techniques have evolved significantly.

The advanced All-Inside arthroscopic technique offers superior functional and aesthetic outcomes in ACL rupture repair.

Additionally, there are different ligamentoplasty techniques, such as single-bundle or double-bundle reconstruction, as well as various graft fixation methods.

During the procedure, the surgeon may also repair other associated injuries identified during the operation, such as a torn meniscus or cartilage damage.

Arthroscopy is performed using a combination of regional and light general anesthesia, depending on the patient’s medical history. A few hours after surgery, the patient can stand up with the help of a functional brace or crutches and return home.

Biological therapies with stem cells can follow the surgery to support and accelerate graft healing and integration.

Is ACL suturing effective?

Older studies involving suturing of the torn ligament did not yield good results.

However, in the past five years, a new technique called Dynamic Intraligamentary Stabilization (DIS) using the Ligamys system has been applied in selected cases of ACL rupture with specific indications. This method allows for preservation of the native ACL, but requires surgical removal of the fixation materials after 6 months.

However, related studies are still ongoing.

What is recovery like after ACL surgery?

Postoperative rehabilitation is a crucial and integral part of the patient’s return to daily and athletic activities. Physiotherapy initially focuses on restoring the full range of motion in the knee joint and preventing further muscle loss. It then progresses to strengthening exercises, specifically designed to protect the new ligament. In the final stage, the program includes sport-specific exercises aimed at reintegrating the patient back into their athletic activity.

Although returning to everyday activities is relatively quick, full return to intense sports activities usually occurs after about six months.