Anterior cruciate ligament (ACL) injury


Anterior cruciate ligament (ACL) injury


Injuries of the ACL are much more common than posterior cruciate ligament injuries. One of the strongest ligaments in the knee is the anterior cruciate ligament. It connects the femur to the tibia and is located in the center of the knee; this is why it forms what is called the central pivot of the knee.

The ACL has an essential role in the rotational movement of the knee because it keeps the tibia and the femur stable when the knee twists. Its rupture results from a major sprain

Sever knee sprain

The rupture is often due to the practice of so-called “pivot” sports such as football, volleyball, handball, skiing, tennis, rugby or hockey.


The main symptomatology of an ACL rupture is the rotational instability of the injured knee.

There are two options to treat a ruptured anterior cruciate ligament:

– Conservative treatment consists of rehabilitation aimed at maintaining a certain stability of the knee. This is the least invasive option and still allows for future surgery if symptoms fail to improve.

However, the lack of a true repair of the ligament could prevent a return to certain sports and potentially restrict activities of daily living

– Surgical treatment treatment consists of reconstruction of the anterior cruciate ligament, or ligamentoplasty, using a graft.

The surgical approach has a success rate of 80-90% and allows for repair of the ligament and a return to sporting activities.

Risks of surgery including infection, DVT and failure of the repair which would require surgical revision.


Post-operative rehabilitation:


Initial physical therapy consists of range of motion (ROM) exercises, often with the guidance of a physical therapist. Range of motion exercises are used to regain the flexibility of the ligament, prevent or break down scar tissue from forming and reduce loss of muscle tone.

Range of motion exercise examples include: quadriceps contractions and straight leg raises. In some cases, a continuous passive motion device is used immediately after surgery to help with flexibility. The preferred method of preventing muscle loss is isometric exercises that put zero strain on the knee. Knee extension within two weeks is important with many rehab guidelines.

Approximately six weeks is required for the bone to attach to the graft. However, the patient can typically walk on their own and perform simple physical tasks prior to this with caution, relying on the surgical fixation of the graft until true healing (graft attachment to bone) has taken place. At this stage the first round of physical therapy can begin. This usually consists of careful exercises to regain flexibility and small amounts of strength. One of the more important benchmarks in recovery is the twelve weeks post-surgery period. After this, the patient can typically begin a more aggressive regimen of exercises involving stress on the knee, and increasing resistance. Jogging may be incorporated as well.

After four months, more intense activities such as running are possible without risk. After five months, light ball work may commence as the ligament is nearly regenerated. After six months, the reconstructed ACL is generally at full strength (ligament tissue has fully regrown), and the patient may return to activities involving cutting and twisting. Recovery varies highly from case to case, and sometimes resumption of stressful activities may take a year or longer.