A patient met with Road Traffic Accident with injury to the left knee. Dial test was positive. What could be the cause ?
Dial test or Tibial External Rotation Test: 

This is the test for posterolateral instability.
The tibia is externally rotated on femur first at 30° flexion and then at 90° flexion. Comparison is made with the normal side.
An increase in external rotation of greater than 10°


At 30° of flexion but not at 90° indicates an isolated posterolateral corner injury.
At both 30° and 90° of flexion indicates injury of both posterior cruciate ligament and posterolateral corner.


The posterolateral corner (PLC) is a complex that includes the lateral collateral ligament (LCL), popliteus tendon, fabellofibular ligament, arcuate ligament, popliteofibular ligament, and the short lateral ligament.
Medial Collateral Ligament Injury
Posterolateral Corner Injury
Lateral Meniscus Tear
Medial Meniscal Injury