Complete distal biceps tendon ruptures require prompt surgical management for optimal functional and aesthetic outcome. The
need exists for a valid and reliable diagnostic tool to expedite surgical referral. We hypothesized complete distal biceps
tendon ruptures result in an objectively measurable anatomic landmark (the distance between the antecubital crease of the
elbow and the cusp of distal descent of the biceps muscle, or the biceps crease interval), as a result of proximal retraction
of the musculotendinous complex. We established normal biceps crease interval values and biceps crease ratios between dominant
and nondominant arms in 80 men with no history of biceps injury (average age, 43 years). The mean (± standard deviation) biceps
crease interval for dominant and nondominant arms was 4.8 ± 0.6 cm. The mean biceps crease ratio was 1.0 ± 0.1. We measured
the biceps crease interval and biceps crease ratio on 29 consecutive patients presenting with a possible complete distal biceps
tendon rupture. Using a diagnostic threshold of a biceps crease interval greater than 6.0 cm or biceps crease ratio greater
than 1.2, the biceps crease interval test had a sensitivity of 96% and a diagnostic accuracy of 93% for identifying complete
distal biceps tendon ruptures, making it a valid and reliable tool for clinicians to identify cases requiring urgent surgical
referral.
Level of Evidence: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.
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patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations
were conducted in conformity with ethical principles of research, and that informed consent for participation in the study
was obtained.