Cruciate Ligament Rupture

The cruciate ligaments (anterior and posterior) together with the collateral ligaments hold the knee joint together. They limit extension of the shin, guide the joint during the movement and thereby give it the necessary stability.

The anterior cruciate ligament ruptures ten times more often than the posterior cruciate ligament, and these injuries have increased significantly in the last few decades.


The knee joint has a complex structure and is therefore very easily injured. As the most strained joint in the body, it bears nearly the entire body weight. Stability and mobility are provided by an inner and outer ligament as well as a front and rear cruciate ligament. Two cartilaginous disks, the menisci, function as shock absorbers. Sports usually cause tears in the anterior cruciate ligament when the knee is overstretched or twisted too far with a fixed lower leg. A rupture of the posterior cruciate ligament is often caused by a direct impact from the front against the lower leg or unintentional overextension of the knee joint.


In case of a cruciate ligament rupture, the injured knee joint is severely swollen, painful and cannot be fully extended or flexed. Once the acute complaints have abated, a more or less severe instability may remain. This results in "buckling" of the knee joint during certain movements. These may be everyday movements such as climbing stairs, or the complaints may be limited to strenuous physical activity during sports. Over time, instability in the knee joint can cause damage to the menisci and cartilage, and even premature joint wear.


Cruciate ligament rupture can be diagnosed by a doctor externally based on the existing knee complaints. Various load tests can show whether (which is typical for cruciate ligament rupture) the gait is uncertain, the joints buckle and the knee is unstable. What is known as the drawer test (drawer sign) can be used to determine the location of the cruciate ligament rupture: If it is possible to shift the shin back compared to the thigh bone (= posterior drawer sign), the posterior cruciate ligament is frequently ruptured; if on the other hand the shin can be shifted significantly forward (= anterior drawer sign), the anterior cruciate ligament may be ruptured.

Knee X-rays are used primarily to exclude fractures (broken bones). However, they are not suitable to show the ligament rupture. Magnetic resonance tomography (MRT) is suitable for this purpose. The doctor can also diagnose possible accompanying injuries in the course of this examination.


Cruciate ligament ruptures are usually corrected with cruciate ligament replacement surgery. This means that the damaged cruciate ligament is replaced with a piece of the body’s own tendons, for example the semitendinosus tendon. Since the replacement material has to grow into the bony canal for 10 to 12 weeks, stabilising orthoses are recommended after the operation. Ottobock offers a selection of high-quality products here.

Not every ruptured cruciate ligament has to be operated. Every case is decided individually depending on age, activity, the ability to participate in sports, motivation and the everyday abilities of the patient. Alternatively, the thigh musculature can be trained to provide sufficient stability for everyday movements. However, it must be considered that when the cruciate ligament is torn, cartilage damage can occur early on without treatment. In the case of recreational and professional athletes, it is also possible that further accidents cause additional injuries to the cartilage and meniscus.

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