The patellar apprehension test is performed to confirm the doctor's suspicion that a patient has experienced previous patellar instability, such as patellar subluxation or dislocation.
How to perform the patellar apprehension test
The patient lies face up on an examination couch, with the surgeon perced on the lower end, holding the patient's ankle with the foot off the couch and the knee flexed to 45 degrees. With the other hand the surgeon holds the patella between finger and thumb and, using moderate force, tries to push it laterally out of the groove of the underlying femur. A positive test is when the patient puts out a hand to stop this movement.
Examination of the patellofemoral joint. Manske RC. Int J Sports Phys Ther. 2016 Dec; 11(6): 831–853.
The moving patellar apprehension test for lateral patellar instability. Ahmad CS, McCarthy M, Gomez JA and Shubin Stein BE. Am J Sports Med. 2009 Apr;37(4):791-6. doi: 10.1177/0363546508328113. Epub 2009 Feb 3.