• Diagnosis
  • Treatment
  • Rehabilitation

Knee Ligament Injuries

Also known as: Anterior cruciate ligament injury, posterior cruciate ligament injury, medial collateral ligament, lateral collateral ligament injury, multi-ligament injuries.

Knee ligaments are strong bands of tissue that are rope-like structures connecting the thigh bone to the shin bone. There are four main ligaments in the knee connecting the femur, (thigh bone) to the tibia (shin bone) or fibula. There are the two cruciate ligaments; the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). These two ligaments prevent the shin bone sliding forward and backwards on the thigh bone. There are two collateral ligaments, one on the inside of the knee, called the medial collateral ligament (MCL) and the other one on the outside of the knee called the lateral collateral ligament (LCL). These act as side-to-side stabilisers within the knee. Injury to knee ligaments causes the joint to be slacker than it would normally be. Ligaments can either be partially torn (sprained) or completely torn (ruptured).

The anterior cruciate ligament (ACL) is one of the most important ligaments within the knee and is often torn when running or twisting, particularly in female athletes, when landing while the body is still twisting. Often the knee joint, during injury, is put at an angle, which is a great force through the knee, rupturing the ligament. One of the most famous ACL injuries was to England footballer Michael Owen.

Posterior cruciate ligament (PCL) injuries are less common than anterior cruciate ligament injuries and commonly occur when landing on the point of the knee, (e.g. falling whilst playing rugby) or when hitting the knee directly onto an object such as motorcycle riders hitting cars or dashboard injuries during road traffic accidents.

Ligament injuries can occur in a wide variety of individuals through sporting injuries, skiing injuries, road traffic accidents or falls.


Following an acute injury, patients will often recall the exact moment they tore their ligament and often associate it with a loud pop or noise. There is usually immediate knee swelling and because of pain and wobbliness within the knee, patients are unable to continue the activity they were doing at the time of the injury.

If these injuries occur to then the patient should rest, apply ice, use compressive bandages, elevate the knee (RICE) and seek expert advice from either a physiotherapist or a doctor

Patients with anterior cruciate ligament injuries usually present symptoms of instability within their knee, which are usually described as “wobbliness” and lack of confidence, particularly when turning corners, or that their knee feels “a bit like jelly.” The knee will collapse underneath them if they turn quickly and will sometimes collapse when walking in a straight line.


On being seen, a careful history should be taken from the patient to try and identify what injury was sustained. The knee will be examined and assessed for laxity. The treating doctor or physiotherapist may request an x-ray, but most ligament injuries are diagnosed by an MRI scan.

Knee Ligament Injuries

Treatment will depend on the nature of the injury and the ligament or ligaments affected.

Anterior Cruciate Ligament

The first route for treatment following anterior cruciate ligament injury is to have physiotherapy to help rehabilitate the acute injury. Torn anterior cruciate ligaments do not heal themselves. However, physiotherapy helps to train the muscles around the knee to produce secondary stability. Patients who do not participate in contact sports, or sports which require turning, often respond well with conservative treatment with physiotherapy. However, in those patients where the knee remains unstable, ligament reconstruction surgery is advised.

Anterior Cruciate Ligament Reconstruction (ACL Surgery)

Anterior cruciate ligament reconstruction is performed through keyhole surgery where either the hamstring tendons of the patient or a piece of tissue taken from the patellar tendon are used to replace the injured ACL. The surgery is usually performed as a day-case procedure or an overnight stay. Patients will tend to be in a knee brace and on crutches for between two and six weeks. Following a successful course of physiotherapy they will often return to contact sports within six to nine months.

Posterior Cruciate Ligament Injuries (PCL Injuries)

Posterior cruciate ligament injuries are uncommon in isolation, but are often successfully treated with physiotherapy. If a patient’s knee feels unstable, then ligament reconstruction surgery is required, which is performed through keyhole surgery.

Lateral Collateral Ligament Injuries (LCL Injuries)

Lateral collateral ligament injuries are serious injuries to the knee which rarely occur in isolation. Usually they cannot be treated conservatively and require surgical exploration. It is essential that any associated injuries are identified prior to procedures being performed.

Medial Collateral Ligament Injury Treatment (MCL)

An isolated medial collateral ligament injury, (i.e. there is no associated injury) will usually be successfully treated with physiotherapy, taking from three to six months to improve. A very small group of patients require surgery.

Knee Ligament Injuries

There are many different types of knee ligament injury as shown, not all requiring surgery. For non surgical ligament injuries the physiotherapy management will involve assisting the healing of the soft tissue of the ligament. The main techniques involve manual therapy (hands on tissue stretches) as well as inflammatory response management. Following the resolution of the soft tissue then strengthening and proprioception (joint balance and control) exercises will return the knee to full function.

For the post operative reconstructed exercises, the rehabilitation can take several months. The main aim of recovery is to improve strength of the quadriceps, gluteals and hamstrings muscles as well as improve proprioception of the operated knee joint. There is intensive exercises to rebuild this strength involving home regimes and gym based programs.