RESUMO
BACKGROUND: Partial tears of the distal biceps tendon can be difficult to diagnose based on clinical examination and magnetic resonance imaging (MRI). METHODS: Patients from a single surgeon's practice from 2000 to 2018 with a partial distal biceps tendon tear were retrospectively reviewed to determine the utility of the distal biceps palpation-rotation test in the detection of partial tears. This test is performed by palpating the bicipital tuberosity at the lateral forearm while ranging the forearm from supination to pronation with the arm adducted at the patient's side and the elbow flexed to 90°. A positive test elicits tenderness at the tuberosity with the arm in pronation but not in supination. Examination findings were correlated with MRI reports confirming a partial tear. Twelve cadaveric arms were dissected to determine overall pronosupination range of motion, the degree of pronation at which the bicipital tuberosity is maximally palpable, and anatomic measurements of the bicipital tuberosity to guide the optimal technique when carrying out the maneuver. RESULTS: Ninety-nine patients were diagnosed with a partial distal biceps tendon, of whom 34 had available MRI reports and complete physical examination documentation. Thirty-three of 34 patients (97%) had partial tears on MRI. The hook test was negative in all cases. All patients had tenderness with resisted supination. In those with MRI-confirmed partial tears, the palpation-rotation test was positive in all patients (100% sensitivity). The bicipital tuberosity was maximally palpated at the dorsolateral forearm at a mean 20° of pronation, and the proximal and distal boundaries of the radial tuberosity were 2.5 cm and 5.3 cm, on average, distal to the radial head, respectively. CONCLUSION: A positive palpation-rotation test was seen in 33 of 33 patients (100% sensitivity), as correlated with MRI. The combination of an intact distal biceps tendon within the antecubital fossa, tenderness on resisted supination, and a positive palpation-rotation test are highly suggestive of a partial distal biceps tendon tear.