Knee Orthopaedic Test: Patellar Apprehension Sign

The Patellar Apprehension Sign Test is a clinical examination technique used to assess the stability of the patella (kneecap) and to diagnose patellar instability. During the test, the examiner gently pushes the patella laterally to assess for any signs of apprehension or discomfort in the patient.

Here are the step-by-step instructions to perform the Patellar Apprehension Sign Test:

1. Position the patient in a supine (lying on their back) position on an examination table with their legs extended.
2. Place one hand on the patient's thigh above the knee and the other hand on the lower leg below the knee.
3. Use the hand on the lower leg to push the patella laterally (toward the outer aspect of the knee) while observing the patient's reaction.
4. Look for any signs of apprehension or discomfort in the patient, such as tightening of the quadriceps muscle or a grimace of pain.
5. If the patient shows signs of apprehension or discomfort, hold the patella in that position for a few seconds while observing any further reactions.
6. Release the patella and ask the patient if they experienced any pain during the test.
7. Repeat the test on the other knee if necessary.

It's important to note that the Patellar Apprehension Sign Test should be performed by a trained healthcare professional and should not be attempted by individuals without proper training. Additionally, the test may not be appropriate for all patients, and alternative examination techniques may be necessary in some cases.

In a normal Patellar Apprehension Sign Test, the patient should not experience any pain or discomfort when the patella is pushed laterally. However, if the patient experiences apprehension or pain, it may indicate patellar instability.

References:

1. Kujala UM, Jaakkola LH, Koskinen SK, Taimela S, Hurme M, Nelimarkka O. Scoring of patellofemoral disorders. Arthroscopy. 1993;9(2):159-163. doi: 10.1016/s0749-8063(05)80387-7
2. Colvin AC, West RV. Patellar instability. J Bone Joint Surg Am. 2008;90(12):2751-2762. doi: 10.2106/JBJS.H.00143
3. Fulkerson JP. Diagnosis and treatment of patients with patellofemoral pain. Am J Sports Med. 2002;30(3):447-456. doi: 10.1177/03635465020300032201
4. Smith TO, Donell ST, Clark A, et al. The development, validation and internal consistency of the Norwich Patellar Instability (NPI) score. Knee Surg Sports Traumatol Arthrosc. 2014;22(12):3246-3255. doi: 10.1007/s00167-014-3125-x