A 4-degree tibial external rotation difference between knees during posterolateral corner assessment corresponds to which grade?

A 4-degree tibial external rotation difference between knees during posterolateral corner assessment corresponds to which grade?

• A. grade 1
• B. grade 2
• C. grade 3
• D. grade 4

Answer: (A)

In posterolateral corner assessment, the grade reflects how much the tibia can externally rotate compared to the opposite knee. A small amount of laxity indicates only mild involvement. A 4-degree external rotation difference is within that mild range, which corresponds to Grade I. Practically, this means there’s minimal PLC laxity, not a severe instability. Measurement is typically done with the knee around 30 degrees of flexion to isolate the PLC, using a goniometer or inclinometer to compare sides. Higher degrees of deformity would indicate higher grades, but 4 degrees sits in the mild category.

In posterolateral corner assessment, the grade reflects how much the tibia can externally rotate compared to the opposite knee. A small amount of laxity indicates only mild involvement. A 4-degree external rotation difference is within that mild range, which corresponds to Grade I. Practically, this means there’s minimal PLC laxity, not a severe instability. Measurement is typically done with the knee around 30 degrees of flexion to isolate the PLC, using a goniometer or inclinometer to compare sides. Higher degrees of deformity would indicate higher grades, but 4 degrees sits in the mild category.