The Flexion Initiation Test and an Evidence-Based Diagnostic Algorithm for Distal Biceps Tendon Tears

PURPOSE: The purpose of this study was (1) to assess the flexion initiation test’s (FIT) ability to detect distal biceps tendon tears (DBTT) in a cohort of consecutive patients presenting with elbow pain and (2) to generate a reliable evidence-based diagnostic algorithm using a combination of both the FIT and hook tests. METHODS: We performed a retrospective review of 125 consecutive patients who presented with elbow pain, all of which had the FIT and hook test performed prior to imaging/further intervention. The integrity of the tendon was determined during surgery or by magnetic resonance imaging. Sensitivity, specificity, positive predictive value, and negative predictive value were determined for the FIT and hook test. RESULTS: Our evidence-based diagnostic algorithm showed that when both test results are in agreement, there is a 100% diagnostic accuracy for detecting what prior authors have termed surgically indicated tears (complete ruptures and high-grade partial tears) and biceps pathology that can be treated with nonoperative management. The FIT demonstrated 100% sensitivity for surgically indicated tears. The hook test demonstrated 100% sensitivity for complete ruptures, but 18% sensitivity for diagnosing partial tears. CONCLUSIONS: The FIT, which is aimed at improving diagnostic acuity of high-grade partial thickness tears, demonstrated a 93% sensitivity and 96% specificity overall and a 100% sensitivity for complete ruptures and high-grade partial tears. The evidence-based diagnostic algorithm using the combination of the FIT and hook test demonstrates high accuracy for the diagnosis of both complete and high-grade partial DBTTs. The methodology may help to prevent diagnosis delays, improve patient education, and preserve the option for timely primary surgical repair in the treatment of DBTTs. LEVEL OF EVIDENCE: Level IV, diagnostic.