What is your suspected diagnosis?

Distal biceps tendon rupture

What physical exam maneuver(s) can help you confirm your diagnosis?

Hook Test: With the patient at rest, you should be able to hook your finger around the patient’s distal biceps tendon near insertion at the antecubital fossa. If not, a tear should be suspected.

Yergason’s Test: Resisted elbow flexion and supination to evaluate strength of biceps tendon/muscle and for reproduction of pain.

What is your initial workup in the ED?

A complete distal biceps rupture is largely a clinical diagnosis based on the mechanism of injury (strong, mechanical overload during eccentric muscle contraction of the biceps) as well as a positive hook test and Yergason’s test. However, X-ray of the elbow can help rule out fracture, especially given an atypical mechanism of injury, such as in our patient. 

• Pearl: Bedside ultrasound is also helpful in the hands of a skilled operator, as imaging of the distal biceps with other modalities can be difficult. See below for example images for further guidance.

Image A (top left): Ultrasound Distal Biceps (Tendon Rupture) [1]; Image B (top right): Ultrasound Distal Biceps (Normal, [1]); Image C (bottom image): Probe placement for evaluation distal biceps in long-axis view (Peter Martin’s Image)

What imaging confirms the diagnosis?

Imaging is not necessary to confirm a distal biceps rupture. If needed however, such as in preoperative evaluation, this can be performed by diagnostic ultrasound or MRI (see image below). MRI is usually obtained on an outpatient basis. When performed, it should be done soon after discharge from the ED as best surgical outcomes are obtained when surgery is performed within 2-3 weeks of injury occurrence [2,3].

Image D: Axial PF FS Sequence at the level of the Radial Tuberosity (Insertion point of the conjoint distal biceps tendon shows hemorrhage and edema at the insertion, and lack of visualization of the tendon. There is also edema and hemorrhage between the fascial planes of the Brachioradialis and Pronator Teres, and edema within the superficial soft tissues (Case Image, supplied by Peter Martin).

What is your management and disposition?

While proximal biceps injuries and tears may be managed conservatively initially, complete distal biceps tears warrant timely surgical intervention for most patients (except for the most low demand and sedentary patients). These injuries need to be operated on within 2-3 weeks of the injury for best outcomes with regards to strength and appreciable muscle deformity [4]. Therefore, patients should have urgent follow up with Orthopedic surgery. No bracing or casting is needed.