Patellar Apprehension Test
The patellar apprehension test is used to evaluate for patellofemoral instability. To perform this test, have the patient lie supine and relax her quadriceps muscle. With the knee slightly flexed, attempt to slide the patella laterally or medially with your thumb. The test is positive if the patient experiences a sensation that her knee is going to give out or is unstable. Laxity alone is not sufficient for a positive test.