Hook test is performed by asking the patient to actively flex the elbow to 90° and to fully supinate the forearm.
The examiner then uses index finger to hook the lateral edge of the biceps tendon.
What does a positive Hook Test mean?
The examiner should be able to “hook” an index finger under the cordlike structure in the antecubital fossa if the biceps tendon is intact.
If the distal biceps tendon is completely ruptured, the examiner won’t feel the cord-like structure under which the he hooks the finger.
Some conditions give a false positive results:
Intact lacertus fibrosis.
Underlying brachialis tendon.
Sensitivity & Specificity
Shawn W O’Driscoll1 found that the hook test is a highly sensitive and specific test for assessment of distal biceps tendon avulsions:
Sensitivity: 100 %
Specificity: 100 %
The examiner must be sure to hook the lateral edge of the biceps tendon, not the medial edge, because the lacertus fibrosus might be mistaken for an intact biceps tendon.
Shawn W O’Driscoll, Lucas B J Goncalves, Patricio Dietz: The hook test for distal biceps tendon avulsion. Am J Sports Med. 2007 Nov;35(11):1865-9. doi: 10.1177/0363546507305016. Epub 2007 Aug 8. PMID: 17687121.