Polk’s test is an easy to learn, easy to perform and simple to interpret test that can help the clinician differentiate between Lateral Epicondylitis and Medial Epicondylitis.
It aids the clinician in establishing a working diagnosis and also serves as an educational tool for the patient in helping them to better understand their condition and avoid the specific activities that aggravate the injury.
Clinically Relevant Anatomy
Wrist extensor group
- M. extensor digitorum
- M. extensor digiti minimi
- M. extensor carpi ulnaris
All these muscles have the same origin: the lateral epicondyle.
Wrist flexor group
- M. pronator teres
- M. flexor digitorum superficialis
- M. flexor carpi radialis
- M. flexor carpi ulnaris
- M. palmaris longus
All these muscles have the same origin: the medial epicondyle.
The use of Polk’s test may help the clinician to diagnostically differentiate between Lateral Epicondylitis en Medial Epicondylitis, 2 of the most common causes of elbow pain.
Polk’s test also helps to definitively indentify the method of lifting that is best to be avoided by the patient .
The mechanism of the Polk’s test is very straightforward. When the hand grasps an object, tension is placed on both the flexors and the extensors of the wrist. The motion of lifting an object, aggravates the tension on the primary affected muscle group with resulting mechanical strain at the inflamed musculotendinous attachment site .
With the patient seated and the elbow flexed, the patient is instructed to lift an object of approximately 2.5 kg. An appropriately weighted sand bag, hand weight, heavy purse or thick book will usually suffice for the purpose of the test.
The test is performed in 2 separate phases;
Phase 1: diagnosis of lateral epicondylitis
The patient grasps the object with the palm facing the floor (pronation of the forearm) and is instructed to attempt to lift it up the object. Pain produced in the elbow, typically in the region of the lateral epicondyle, upon this manoeuvre is suggestive of Lateral Epicondylitis.
In the absence of lateral epicondylitis however, the patient usually performs this manoeuvre quite easy and without pain.
Phase 2: diagnosis of medial epicondylitis
This phase involves the seated patient , with a flexed elbow. The patient is instructed to grasp the object with the palm up (supination of the forearm) and attempt to lift the object. Elbow pain, usually in the region of the medial epicondyle, produced with this manoeuvre is suggestive of Medial Epicondylitis.
In the absence of medial epicondyilits, the patient performs this manoeuvre quite comfortably.
Other special tests
As there is a lack of strong evidence supporting the use of Polk's test to differentiate between Lateral Epicondylitis and Medial Epicondylitis, a clinician may wish to perform the following special tests to help confirm their diagnosis;
- Medial Epicondylitis test (Golfer's elbow test)
- POLKINGHORN B.S., A novel method for assessing elbow pain resulting from epicondylitis, Journal of chiropractic medicine, 2002, vol. 1 n° 3, pag. 117 – 121, level of quality D