Understanding A DISTAL Biceps tendon Rupture
In general, a distal biceps tendon rupture is a dramatic and serious injury. The distal biceps tendon attaches to the proximal radius bone in the forearm. The biceps muscle is primarily responsible for flexion (bending) of the elbow and supination. Most commonly, the injury occurs when an athlete has a sustained contraction of the biceps with the palms facing upwards, such as when doing a biceps curl or lifting a heavy object. A rupture can be classified as partial or complete and typical occurs in a few possible locations. The injury can occur within the muscle belly, within the tendon or the bony attachment site of the distal biceps. Of note, biceps tendon ruptures typically occur in males in their dominant arm.
Evaluation OF Distal Biceps Tendon
Athletes will usually note a painful and audible pop followed by notable swelling and bruising within the bend of the elbow. Additionally, there may be a palpable mass just above the elbow, which represents the retracted muscle and tendon after the rupture. This exam finding is typically referred to as a "Popeye deformity" as it resembles the bicep of the cartoon character Popeye. A hook test can be performed to check the integrity of the distal biceps tendon (pictured below). Weakness will also be reported with flexion and supination of the elbow. Tip: The biceps plays a large role in supination and less so flexion of the elbow, which is done by the brachialis muscle. Therefore testing flexion alone may not give the full extent of the injury. The diagnosis can be confirmed with an MRI or ultrasound of the affected area.
Hook Test
With elbow flexed to 90 degrees the finger is hooked around the distal biceps tendon to check its integrity.
Treatment and Return to Play
In general, a distal biceps tendon rupture is a dramatic and serious injury. Nonoperative treatment is not typically a reasonable option for athletes to return back to sports at their pre-injury levels. Research has shown that nonoperative treatment may lead to significant loss of strength with supination, flexion and grip. On the other hand, patients with partial tears can be treated with physical therapy to improve strength and regain full range of motion. Operative management is focused on reattaching the distal biceps tendon back to the bone, which can be done through several different methods. Post-surgical care may consist of splinting the arm at 90 degrees and supinated for about a week and progressing back to gentle range of motion. Progressive strengthening usually will occur 6-8 weeks after surgery and return at 4-6 months based on strength and ROM.
Reference:
Thomas JR, Lawton JN, Biceps and Triceps Ruptures in Athletes. Hand Clin. 2017 Feb;33(1):35-46. doi: 10.1016/j.hcl.2016.08.019.
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