Torn anterior cruciate ligament (ACL)

Ruptured anterior cruciate ligament is the most common type of traumatic injury of the soft tissues in the knee.


Next to the knee joint alone , which is made out of thigh bone, and calf bone and meniscus, structures of the soft tissues of the knee are very important part of the knee joint, among which are:

  • Joint capsule, which is generally strengthening the knee joint
  • The sideways ligaments restricting the knee from backsliding, and sliding to the sides
  • Inner cruciate ligaments securing the stability of the knee joint in the ventrodorsal direction - anterior cruciatum ligamentum (ACL), posterior cruciatum ligamentum (PCL)
  • Menisci (cartilage plates elevating the pressure burden)

Traumatic injury of the knee joint leads very often to damaged structures of the soft tissues of the knee, usually it is the anterior cruciate ligament (ACL), which is essential for stability of the knee joint, because it restricts the calf bone from moving forwards against the thigh bone.

Next to the anterior cruciate ligament is often getting injured also meniscus. Bigger trauma leads to a complete injury of the anterior cruciate ligament, meniscus and inner sideways ligament. This injury - also called „unhappy triad” - which is very painful and it basically disrupts the stability of the knee.


CLCoTrapiFotbalistyInjury of the soft tissues of the knee occurs usually during sport, especially during football, skiing, volleyball, rugby, handball, floorball, basketball etc… That means during sport, when you need fast change in the directions or stop abruptly. Injury occurs often through indirect violence on the knee in the form of outer rotation of the calf bone and its outwardly deflection.

Clients often describe during the injury a feeling of non-painful pop in the joint, sometimes they feel their knee jumping forward and inwardly, furthermore it is accompanied by a sharp pain with a subsequent inability to step on the affected leg, and the knee is also reflexively blocked in a slight bend.

Painfulness of the injured joint is depending on the severity of the knee injury. During an isolated rupture of the anterior cruciate ligament, the primary pain would subside usually after fourteen days, however during combined injury („unhappy triad”) the pain often remains for longer period of time, especially because of the injured meniscus, which is with its disrupted part irritating the structures inside the knee.

After the attenuation of the acute pain, clients often describe an unpleasant pain from the inner side of the knee. Among other problems relating to this injury is also significant swelling of the knee joint, lowered range of mobility and general stiffness of the knee joint. Quick application of the lymphatic drainage can lower the swelling and also the painfulness and thanks to that increases the range of mobility.

Another complication is lowered muscle strength, feeling of instability and convulsive painfulness of the surrounding muscles, which are reflexively trying to contract and form protective splint. That is for the injured joint basically positive, however if the client has very unpleasant or even spastic pains, it is necessary to relieve these muscles. Radial shock wave can be used, it brings instant relief to the painful muscles and the tension fades away.

Instability of the knee is manifesting by sudden drop of the knee joint during walking.

Injury of the soft tissues of the knee disrupts the even transfer of the burden from the thigh bone to the calf bone. That leads to overloading of the undamaged structures of the knee joint. If the therapy is not started in time, there is a risk of further damage to the structures of the knee and development of degenerative process which can result in very painful arthrosis of the knee joint.


Injury of the soft tissues of the knee is diagnosed usually on orthopedy thanks to clinical examination. For explanation of the injury are used imaging methods - especially magnetic resonance, on which are soft tissue structures very well visible.

In therapy we have two options of treatment - conservative and surgical. When choosing therapy, individual approach to every client is very important - we have to take in mind the burdening involved on the knee joint, sport activity of the client, age, motivation and especially associated injuries.

Methods of modern physiotherapy to inhibit the acute post-injury problems with damaged soft tissues of the knee (well led physiotherapy, use of mechanical lymphatic drainage and application of shock wave) are described in the article Torn anterior cruciate ligament - what to do directly after the injury.

Exercise tutorials:

More articles about the topic:

Author: Mgr. Iva Bílková, FYZIOklinika fyzioterapie Ltd, Prague, Czech Republic

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