Understanding the Dial Test (Posterolateral Corner Test) Assessment
To detect **Posterolateral Corner (PLC) instability** and differentiate between PCL-only injury and combined PCL/PLC injury.
Watch How It's Done
How do I start?
Patient is prone with the knees flexed to **30°** and then **90°**.
What happens?
The examiner stabilizes the thigh and applies a **maximal external rotation force** to the foot/ankle at both the 30° and 90° knee flexion positions. The degree of external rotation is measured.
In Plain English
What Does a Positive Result Mean?
An increase of **>10° of external rotation** compared to the unaffected side. **30° only:** PLC injury. **90° only:** Isolated PCL tear. **Both 30° and 90°:** Combined PLC and PCL injury.
Helpful Tip:
A positive test at 30° indicates PLC involvement, as the collateral ligaments are relatively slack at this angle.
Safety First
This guide is to help you understand what happens in a clinic. Do not try to diagnose yourself. If you have severe pain, swelling, or cannot put weight on your leg, please visit an urgent care center or your doctor immediately.
Other Knee Tests
Pivot Shift Test
To dynamically assess for **anterolateral rotatory instability** of the knee, which is highly indicative of a **complete ACL tear**.
Posterior Drawer Test of the Knee
To assess the integrity of the **Posterior Cruciate Ligament (PCL)**.
Posterior Sag Sign (Gravity Drawer Test)
To detect a rupture of the **Posterior Cruciate Ligament (PCL)** by observing the effect of gravity.
Slocum Test (Anterolateral Rotatory Instability)
To assess for **anterolateral rotatory instability** and the function of the **Anterolateral Ligament** (a dynamic variant of the Anterior Drawer).