Anterior Cruciate Ligament (ACL) Injury

The anterior cruciate ligament (ACL) is one of the main stabilizers of the knee joint and is especially vulnerable to injury during sports that involve sudden changes of direction, pivoting, cutting, and jumping. Once torn, the ACL does not heal on its own. In most active patients, surgical reconstruction is required to restore knee stability, protect the meniscus and cartilage, and reduce the risk of future osteoarthritis.

If an ACL tear is left untreated, recurrent episodes of the knee “giving way” can lead over time to meniscal tears and cartilage damage, resulting in chronic pain and limitation of movement.

What Are the Symptoms of an ACL Tear?

• A popping or snapping sensation at the time of injury
• Sudden, severe pain in the knee
• Rapid swelling of the knee due to bleeding inside the joint
• Inability to continue the game or training session
• Later on: a feeling of instability or “giving way”, lack of confidence when going down stairs, difficulty with sudden direction changes and landing from a jump

In the chronic stage, instability episodes may occur without significant pain. If pain and swelling keep recurring, a concomitant meniscal tear or cartilage injury should be suspected.

How Is an ACL Tear Diagnosed?

In the first days after injury, pain and swelling may limit a full physical examination. For this reason, a repeat assessment 7–10 days after trauma is often helpful.

The main diagnostic tools are:

• Physical examination: Lachman test, pivot-shift test, anterior drawer test
• MRI: Provides detailed assessment of the ACL, menisci and cartilage surfaces
• X-ray: Performed in the early phase to rule out associated fractures

How Is ACL Reconstruction Surgery Performed?

ACL reconstruction is performed using a fully arthroscopic (keyhole) technique. Through small incisions, a camera and fine instruments are introduced into the joint, which minimizes soft tissue damage and supports faster recovery.

1) Arthroscopic Evaluation of the Knee

The surgeon systematically evaluates the entire joint, including the menisci, cartilage surfaces and ligament structures. If there is a meniscal tear or cartilage lesion, it can usually be treated in the same session.

2) Graft Preparation

In most cases, the new ligament is created from the patient’s own tissue:

• Hamstring tendon graft
• Patellar tendon graft
• Quadriceps tendon graft

The harvested tendon is prepared to the appropriate thickness and strength to function as the new ACL.

3) Tunnel Creation and Graft Placement

Precise bone tunnels are created in the femur and tibia at the anatomical insertion sites of the ACL. The graft is then passed through these tunnels and positioned inside the joint along the natural course of the ligament.

4) Graft Fixation

The graft is secured within the tunnels using special implants (such as interference screws or suspension devices). The knee is taken through a full range of motion to confirm that graft tension and stability are appropriate.

Postoperative Period

• Hospital stay: usually 1–3 days
• Early assisted walking with crutches after the effect of anesthesia wears off
• A personalized rehabilitation program is planned according to the graft type and any additional procedures (such as meniscal repair)
• In the long term, the graft harvest site does not limit daily activities or sports performance
• Return to sports: approximately 6–9 months for recreational athletes, 9–12 months for professional athletes

For a more detailed description of the rehabilitation process, you can refer to our article on recovery after ACL reconstruction.

Frequently Asked Questions (FAQ)

Can a torn ACL heal on its own?

No. Due to its limited blood supply, a completely torn ACL does not heal spontaneously and cannot regain its stabilizing function without reconstruction.

Is surgery necessary for every ACL tear?

Surgery is usually recommended for active patients, athletes and those who experience instability or giving-way episodes. In less active patients without instability, non-operative treatment may be considered in selected cases.

Which graft is better?

Both hamstring and patellar tendon grafts have specific advantages. The choice depends on the patient’s activity level, anatomy and individual needs, as well as the surgeon’s experience and preference.

When can I start walking after surgery?

Most patients begin controlled walking with crutches on the first day after surgery.

When can I return to sports?

Return to sports typically occurs between 6 and 12 months, depending on the type of sport and adherence to the rehabilitation program.

Does the presence of a meniscal tear change the treatment plan?

Yes. Meniscal tears are often treated during the same operation, and the postoperative rehabilitation protocol is adjusted accordingly.