Knee Ligaments
Functions, ruptures and reconstructive surgery
A knee injury can compromise both stability and movement, making even walking difficult. If you heard a “crack” during physical activity or feel your knee is swollen and unstable, you may have suffered a ligament injury. Knowing how to recognize it and what treatment options are available can help you recover effectively.
What are knee ligaments for?
Knee ligaments are essential for joint stability and proper movement. They are strong bands of connective tissue that link bones together, enabling controlled motion and protecting the knee from excessive strain.
Four major ligaments work together to provide balance and support: the Anterior Cruciate Ligament (ACL) and the Posterior Cruciate Ligament (PCL), located inside the joint, and the Medial Collateral Ligament (MCL) and Lateral Collateral Ligament (LCL), positioned on the outer sides.
Each ligament has a specific function in preventing abnormal movements and maintaining joint stability—both in daily life and during sports.
Which ligament is most prone to rupture?
Among the four ligaments, the ACL is the most commonly torn, particularly in athletes.
Its role as a stabilizer of the tibia in relation to the femur makes it vulnerable to twists and sudden movements, such as quick changes in direction, abrupt stops, or landing from a jump with the knee in valgus.
Sports such as football, skiing, basketball, and rugby increase the risk due to high joint stress and potential direct impacts on the knee.
Symptoms of an ACL rupture
An ACL tear usually presents clear symptoms from the moment of injury.
Often, a “crack” sound is heard, followed by immediate pain and increasing swelling within hours.
The knee loses stability, with a sensation of giving way—especially during lateral movements or when going downhill. Walking becomes difficult and joint control is compromised.
Diagnosis is confirmed through clinical tests and MRI imaging, which assesses the severity of the injury.
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Arthroscopic surgery for ACL reconstruction
When the rupture is complete and instability affects daily life or sports activity, arthroscopic ACL reconstruction is the most effective solution. The process begins with a preparatory phase, reducing swelling and stiffness through pre-surgical physiotherapy.
During surgery, the most suitable graft is selected to replace the torn ligament. Grafts can be harvested from the semitendinosus and gracilis tendons, the patellar tendon, or the quadriceps tendon. In some cases, a donor graft (allograft) may be used.
Arthroscopic surgery is a minimally invasive approach.
Through small incisions, a microcamera and surgical tools are inserted to remove the damaged ligament, prepare bone tunnels in the tibia and femur, and fix the new ligament using screws or cortical buttons. The procedure takes about 60 to 90 minutes and usually requires a short hospital stay.
Recovery and return to sport
Rehabilitation is crucial for effective recovery. During the first few weeks, the focus is on reducing swelling and regaining mobility with the aid of crutches and targeted physiotherapy.
After the first month, the goal shifts to muscle strengthening and gradual recovery of functional movements. Around the fourth month, running can be resumed, although quick direction changes are still to be avoided.
Full recovery of muscle strength and proprioception typically requires 6–9 months, while return to contact sports or competition happens between the ninth and twelfth month, depending on individual progress during rehab. An ACL rupture is a serious injury, but with timely intervention and a structured rehabilitation protocol, full recovery is possible, even for athletes aiming to return to high-level performance.
If you've suffered a knee trauma and suspect a ligament injury, a specialist consultation is the first step in defining the most appropriate treatment path.
F.A.Q.
1. After ACL reconstruction, can I return to my previous sports level
Yes, but recovery takes time and requires a strict rehabilitation protocol. With proper rehab, many athletes return to high-level competition within 9–12 months post-surgery.
2. Can I avoid surgery if my ACL is torn?
In some cases, people with low physical activity levels may compensate for the lack of a ligament with muscle strengthening and targeted physiotherapy. However, for those with active lifestyles or athletic needs, surgery is often necessary to restore full joint stability.
3. How can I prevent another ACL injury?
Improving neuromuscular control, strengthening the knee stabilizers, and using proper landing techniques can reduce the risk. Additionally, using specific braces during early phases of return to sport may offer added protection.