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External Rotation of Knee Joint

- See: Internal Rotation

- Discussion:
    - external-rotation laxity increases w/ knee flexion, w/ largest amount (20 degrees) being seen in the 30-40-deg range of flexion;
    - external rotation is not directly limited by cruciate ligaments;
    - only PCL, which becomes taut at 90 deg of flexion, would be expected to provide restraint should posterolateral structures be injured;
    - external-rotation laxity is markedly increased only when posterolateral structures or LCL, or both, are cut;
    - concomitant loss of PCL results in greater increases in rotation laxity