A patient met with Road Traffic Accident and developed knee pain. Dial test was positive. Structure injured is- (AIIMS May 2012)
|A||Medial Collateral Ligament Injury|
|B||Medial Meniscal Injury|
|C||Lateral Meniscus Tear|
|D||Posterolateral Corner Injury|
Posterolateral Corner Injury
a. When an injured knee is tested for posterolateral instability, external rotation of the tibia on the femur is measured at both 30 and 90 degrees of knee flexion. The test can be done with the patient supine or prone
b. The medial border of the foot in its neutral position is used as a reference point for external rotation. At the chosen knee flexion angle, the foot is externally rotated with force.
c. The degree of external rotation of the foot is measured relative to the axis of the femur and is compared with the opposite leg.
d. External rotation is measured by noting the foot-thigh angle . In addition, the tibial plateaus are palpated to determine their relative positions compared with the femoral condyles.
e. This determines whether the external rotation is caused by the lateral tibial plateau moving posteriorly (posterolateral instability) or by the medial plateau moving anteriorly (anteromedial instability).
f. A 10-degree difference between knees in the amount of external rotation is considered pathological. More than a 10-degree increase in external rotation compared with that of the contralateral side at 30 degrees of knee flexion, but not at 90 degrees, indicates an isolated injury to the posterolateral corner.
g. An increase in external rotation of more than 10 degrees compared with that on the contralateral side at both 30 and 90 degrees of knee flexion indicates injury of both the posterior cruciate ligament and the posterolateral corner.