CASE

A 37-year-old bodybuilder presents to the ED endorsing right upper arm pain. He is visiting from Virginia, and earlier in the day, he was lifting a suitcase from the baggage claim belt at the local international airport. He heard a “snap” accompanied with sudden sharp pain in his right upper arm. He also notes significant swelling along the middle of his arm compared to the contralateral side. The swelling was not present prior to the injury. He took Tylenol for the pain prior to arrival. His vital signs are within normal limits. Physical examination reveals weakness with supination and flexion at the elbow joint. There is mild pain with both passive and active motion.

DIAGNOSIS

distal biceps tendon rupture

DISCUSSION

Biceps tendon ruptures can occur at either the proximal or distal end of the bicep tendon at the origin or insertion of the tendon, respectively [1]. Distal biceps tendon rupture is rare, and the proximal tendon is more often ruptured [2]. In proximal rupture, the long head of the biceps brachii is more likely to rupture than the short head [3]. In distal rupture, the most common mechanism is sudden biceps muscle contraction against a heavy load in a partially flexed position, often with the elbow extended and partially supinated [4]. Prior shoulder injury, fluoroquinolones, chronic anabolic steroid use, tobacco use disorder, age-related tendon degeneration, and, more rarely, dialysis-associated amyloidosis put patients at risk of tendon rupture [5].

On visual examination, the patient may present with Popeye’s deformity, or an over-exaggerated bicep secondary to the retraction of the bicep muscle belly anteriorly along the middle of the upper arm [6]. Physical exam maneuvers, such as the biceps provocation and hook test, can be performed to evaluate biceps tendon rupture. For the biceps provocation test, the patient abducts their arm while flexing about 70 degrees at the elbow joint. Supination in this position should move the muscle belly of the bicep proximally whereas pronation should move the bicep distally towards the elbow. Abnormal or absent movement indicates a positive test, indicating rupture of the biceps tendon [7].

Similarly, the hook test can investigate the integrity of the biceps tendon by directly palpating it just proximal to its insertion on the radial tuberosity near the antecubital fossa. To perform the hook test, the patient abducts the shoulder with the elbow flexed at 90 degrees. The examiner attempts to hook the tendon under their index finger by placing it laterally in the space between the distal humerus and tendon itself. The examiner can then attempt to test the structure of the tendon by advancing it forward. Excessive laxity of the tendon at this point indicates a positive test [7]. An additional, less utilized test is the biceps crease interval (BCI), which measures the distance between the elbow crease in a flexed position and the biceps curve. Distances greater than 6 cm in this position may indicate a complete biceps tendon rupture [8]. In one study, a combination of the hook test and BCI physical exams was shown to have the most diagnostic yield [9].

While often not necessary, imaging can further aid in diagnosis of biceps tendon rupture [10]. Ultrasound is a cost effective and simple test that can be used to assess for rupture easily at bedside. Operators can visualize the tendon using the anterior, posterior, lateral, or medial approaches for thorough examination of the tendon from every angle [11,12]. MRI conducted in the flexion abduction supination (FABS) view can also be useful to distinguish between partial versus complete rupture, as well as tendinosis or bursitis [7].

Management of proximal tendon rupture is usually conservative, with rest, ice, and physical therapy. However, distal biceps tendon rupture often requires surgical repair [3]. Among young athletes, prognosis is good, with most returning to close to full function post-operatively [13]. Patients who present to the emergency department with biceps tendon rupture can be discharged with a sling, pain control, and orthopedic follow-up in one week for re-evaluation and possible non-emergent surgery [2].

CASE RESOLUTION

This patient was discharged from the hospital in a sling. He followed up with orthopedic surgery four days later, and was scheduled for surgery for definitive treatment of distal biceps tendon rupture. He was further advised to no longer use steroids for recreational use.

TAKE-AWAYS

• Biceps tendon rupture is a rare upper arm injury, often as a consequence of sudden force resulting in a snap, and presents with pathognomonic physical exam findings, such as Popeye’s deformity.

• Ultrasound and MRI can aid in diagnosis.

• Management is conservative at first, though non-emergent operative repair may be considered for definitive treatment.

AUTHOR: Ambuj Suri, MD, is a second year emergency medicine resident at Brown Emergency Medicine

FACULTY REVIEWER: Kristina McAteer, MD, is an attending physician and Rhode Island Hospital and Newport Hospital

REFERENCES

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