Figure 1. Sagittal STIR magnetic resonance imaging (MRI) image of the distal biceps tendon.
Figure 2. Coronal STIR MRI view of the distal bicep tendon.
A 29-year-old man presents with left arm pain after lifting a lawn tractor at work. He felt a sharp pain in his elbow when he lifted the tractor and now the arm feels weak. On physical examination of the elbow, the patient has full range of motion. He has no bruising or deformity to the arm. His distal biceps can be felt with a hook test and he has tenderness to palpation over the radial tuberosity at the attachment of the distal biceps tendon. Radiographs are unremarkable for fractures or abnormal findings. Sagittal and coronal STIR magnetic resonance imaging (MRI) images show a partial tear (<50%) of the distal biceps tendon (Figures 1 and 2).
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Distal biceps injuries can be a challenge to diagnose and treat. The distal biceps tendon attaches to the radial tuberosity at the antecubital fossa. The function of the distal biceps is to flex the elbow and supinate the wrist. Partial or complete tears generally occur at the attachment site of the radial tuberosity after a sudden flexion of the elbow while lifting with the arm. Partial tears may have mild symptoms with full range of motion of the elbow and mild pain.
Elbow flexion and supination of the forearm commonly show varying degrees of weakness. Complete tears present with more swelling, ecchymosis, and a positive hook test. The hook test involves the examiner using his/her index finger to hook the intact distal biceps at the antecubital fossa.1
MRI is the diagnostic study of choice to identify partial vs complete tears of the distal biceps tendon. Partial tears through less than 50% of the tendon are usually treated nonoperatively whereas tears greater than 50% may require surgical repair.2,3
The recommended nonoperative treatment varies widely in the literature but in general a period of 2 to 3 weeks of elbow immobilization is recommended, followed by 2 to 3 weeks of full motion without lifting, then another 4 to 8 weeks of lifting restrictions based on the patient’s symptoms. If a patient still has symptoms after 3 to 6 months of nonoperative treatment, surgical detachment and re-attachment of the tendon is the recommended treatment option.2,3
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopaedics for Physician Assistants.
1. Hsu D, Anand P, Mabrouk A, Chang KV. Biceps tendon rupture. In: StatPearls. StatPearls Publishing; 2022 Feb 7. Accessed April 4, 2022. https://www.ncbi.nlm.nih.gov/books/NBK513235/
2. Bain GI, Johnson LJ, Turner PC. Treatment of partial distal biceps tendon tears. Sports Med Arthrosc Rev. 2008;16(3):154-161. doi:10.1097/JSA.0b013e318183eb60
3. Dürr HR, Stäbler A, Pfahler M, Matzko M, Refior HJ. Partial rupture of the distal biceps tendon. Clin Orthop Relat Res. 2000;(374):195-200. doi:10.1097/00003086-200005000-00018