- Discussion:
- this sign is positive in pts with acute or chronic posterolateral instability of the knee;
- knee begins in flexion while an external rotation and valgus stress are applied;
- supine
- valgus stress
- foot in ER
- bring knee from 90 deg flexion to full extension
- feel for palpable “shift” of lateral tibial plateau as it moves anteriorly from a posteriorly subluxed position
- lateral tibial plateau shifts from position of posterior subluxation to a position of reduction as the flexed knee isextended under valgus
stress and w/ foot in external rotation; (w/ the true pivot shift the tibia is internally rotated);
- clunk is appreciatted as the knee is extended;
- plateau subluxates again as knee is flexed in the opposite manner;
- since it describes shift of lateral tibial plateau in opposite direction from true joint shift, its called reverse pivot shift;
- significantly positive reverse pivot shift suggest that PCL, arcuate complex, and the LCL are all torn;
- in the position of tibial inernal rotation, the sign disappears
Observations on rotatory instability of the lateral compartment of the knee: Experimental studies on the functional anatomy and pathomechanism of the true and reversed pivot shift sign.