The purpose of the Dial Test is to diagnose Posterolateral Knee Instability,
Dial Test Differentiates between isolated Postero-lateral corner (PLC) injury and combination of PLC and Posterior Cruciate Ligament injury (PCL)
How it's Performed?
The goal of Dial test is to inspect the external rotation (foot-thigh angle, best measured in a clinical setting)at the knee joint while the knees are in 30° and 90° of flexion .
Patient in prone position :
The clinician flexs the patient knees to 30° and places both hands on the feet of the patient, cupping his heels.
A maximal external rotation force is then applied, and the foot-thigh angle is measured and compared with the other side.
The knees are then flexed to 90°, and again an external rotation force is applied and the foot-thigh angle is measured again
Patient in supine position, there are two possible positions:
Same as in prone position – the knees are held together and bent to 30°, the clinician turns the lower legs and feet outwards and compares the amount of external rotation using the tibial tubercle as point of reference. Repeat the test with the knees at 90°.
The knee is flexed over the side of the bed. The clinician stabilized the thigh and apply an external rotation force through the foot and ankle. Then, the clinician looks for the amount of external rotation of the tibial tubercle, and compare it with the other knee
What does a positive Dial Test mean?
The Dial test is positive when there is more than 10° of external rotation in the injured knee compared to the uninjured knee.
There are two types of different injuries :
An isolated injury to the PLC – more than 10° of external rotation in the injured knee is present at 30° of flexion, but not at 90° of flexion.
Instability of the PCL: more than 10° of external rotation in the injured knee is present at 90° of flexion, but not at 30° of flexion.
A combined injury: more than 10° of external rotation in the injured knee is present at 30° and 90° of flexion. This is an injury of the PCL and the PLC.