Why is complete dislocation of the knee rare

A dislocated knee occurs when the position of the thighbone relative to the shinbone becomes disrupted at the knee joint. It can happen through trauma to your leg, like from falls, sports injuries, and car accidents. A dislocated knee is different than a dislocated kneecap. That occurs when the kneecap bone slips out of place. It can happen when a sudden change of direction or blow occurs while your foot is planted on the ground.

A dislocated knee is a rare but serious injury. Dislocation can damage several important ligaments, blood vessels, and nerves. The health and integrity of the joint and leg may be at risk. The symptoms of a dislocated knee usually occur immediately and worsen over time. Sometimes, the knee may slip back into place following a dislocation.

However, it will be painful, swollen, and most likely unstable. Reduction, or repositioning of the injured joint, is crucial in order to reduce any pressure on the skin, blood vessels, and nerves in the affected area. These tests typically involve determining the stability and range of movement of specific parts of the knee. Since a dislocated knee can cause potentially serious disruption to the blood vessels and nerves of the joint, your doctor will perform an examination to assess if injury to these structures has occurred.

This exam may include:. Additionally, a technique called arteriogram may be used to assess blood vessel damage. It combines an injected dye and X-rays so your doctor can see how your blood flows through the arteries in your legs. CKD is a rare condition in which the knee joint is dislocated at birth. Many factors have been suggested as causes.

It may occur by itself or along with other developmental conditions, such as clubfoot. Doctors diagnose CKD after birth. Four patients had injuries to the peroneal nerve; three of the four also had tears of the popliteal tendon. On MR imaging, the integrity of the anterior cruciate and lateral collateral ligaments was correctly depicted in all 17 patients; evaluation of the posterior cruciate ligament resulted in one false-positive and one false-negative diagnosis of a tear; evaluation of the medial collateral ligament resulted in one false-positive diagnosis of a tear; and one false-positive diagnosis of a tear occurred with evaluation of the popliteal tendon.

Conclusion: Knee dislocations cause extensive disruption of the ligaments that stabilize the knee and the surrounding soft-tissue structures, including the popliteal artery.

Nearly all will result in disruption of the cruciate ligments and, often, injury of the collateral ligaments. An injury to the popliteal tendon denotes a more severe injury. The mechanism of injury that results in a popliteal tendon tear may also increase the possibility of a peroneal nerve injury. Recognition of this pattern of injuries on MR imaging enables precautionary observation for ischemic changes of the foot to be instituted in patients that otherwise may not be considered at risk for acute vascular compromise.

Introduction Traumatic dislocation of the knee is both a rare and severe injury. Case Report A year-old manual labourer presented to the outpatient department with complaints of pain and deformity of his right knee and inability to weight-bear on the right leg. Figure 1. Figure 2. Figure 3. References J. View at: Google Scholar J. View at: Google Scholar P. Vicente-Guillen, J. Henshaw, M. Shapiro, and W. View at: Google Scholar G. Scuderi, R.

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