Which exam test is used to evaluate patellar stability and subluxation risk?

• A. Patellar Apprehension Test
• B. J Sign
• C. Patellar Grind Test
• D. Posterior Drawer Test

Answer: (A)

Evaluating patellar stability and subluxation risk is best done with a test that directly provokes the feeling of potential dislocation and watches the patient’s reaction. The Patellar Apprehension Test does this by gently pushing the patella laterally (often with the knee at 0 to about 20–30 degrees of flexion). A positive finding is when the patient shows apprehension, guards, or attempts to contract the quadriceps to prevent dislocation. This response reflects laxity or insufficiency of the soft-tissue restraints around the patella, signaling a higher risk of lateral subluxation or recurrent dislocation.

The J Sign is a related observation of maltracking seen during knee flexion, where the patella shifts laterally, but it’s more about documenting a tracking abnormality rather than a targeted provocative test for stability. The Patellar Grind Test compresses the patellofemoral joint to assess cartilage wear and pain, not stability. The Posterior Drawer Test evaluates the posterior cruciate ligament, not the patellofemoral stability.