Fast Five Quiz: Are You Prepared to Confront Knee Dislocations?

Richard H. Sinert, DO


November 09, 2015

Anterior dislocation often is caused by severe knee hyperextension. Cadaver research has shown that approximately 30° of hyperextension is required before dislocation will occur.

Posterior dislocation occurs with anterior-to-posterior force to the proximal tibia, such as a dashboard type of injury or a high-energy fall on a flexed knee. The image below shows a radiograph of a posterior dislocation. More than one half of all dislocations are anterior or posterior, and both of these have a high incidence of popliteal artery injury.

Medial, lateral, and rotatory dislocations require varus, valgus, or rotatory components of applied force.

For more on the presentation of knee dislocation, read here.


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