Review Question - QID 212062

This vignette is describing a distal biceps tendon rupture. The most sensitive test for diagnosis of this is the Hook test, which Answer 5 is describing.

Distal biceps ruptures are common injuries amongst middle-aged men. Patients may describe an acute event with a "pop" felt, or may relay more subtle symptoms and present in a delayed fashion. The hook test was initially described by O'Driscoll and colleagues as a simple exam maneuver to either rule-in or rule-out distal biceps rupture. The examiner's finger is brought across the antecubital fossa from lateral to medial, and a cord-like biceps tendon should be palpated if intact (Illustration B). If the examiner's finger is brought from medial to lateral, the robust lacertus fibrosis can be felt and may lead to a false-negative hook test. This simple test maneuver has been shown to be both sensitive and specific for ruptures and thus has appeared on numerous standardized tests.

Miyamoto et al. reviewed distal biceps ruptures repair techniques. They state that the single-incision technique carries a higher rate of nerve injuries, which are mostly lateral antebrachial cutaneous neurapraxias that resolve. The dual-incision technique leads to higher rates of heterotopic ossification, though this rate is low and can be lessened by avoiding dissection through the ulnar periosteum. Both techniques are highly effective and surgeons should use whichever one allows the most anatomic and secure repair.

O'Driscoll et al. performed a cohort study evaluating the hook test's diagnostic utility for complete distal biceps ruptures. Hook test was performed by one clinician in individuals with distal biceps ruptures and compared to the contralateral, intact arm, and to MRI findings. The hook test showed 100% sensitivity and specificity compared to MRI findings which demonstrated 92% and 85%, respectively.

Figure A is a sagittal T1 MR sequence showing complete rupture of the distal biceps tendon with retraction.
Illustration A depicts the insertion of the biceps tendon and the lacerates fibrosis onto the antebrachial fascia. Illustration B depicts the hook test maneuver, bringing the examiner's finger from lateral to medial across the antecubital fossa.

Incorrect Answers:
Answer 1- The long head of the biceps inserts more proximally while the short head inserts distally at the tuberosity.
Answer 2- The biceps received sole innervation from the musculocutaneous nerve.
Answer 3- The biceps is the primary supinator of the elbow, with lesser contributions to elbow flexion. The brachialis is the primary flexor of the elbow.
Answer 4- Anatomic repairs have shown a high rate of success, regardless of the technique employed.