Although it is uncommon, the distal biceps tendon can rupture, typically as the result of mechanical overload during eccentric muscle contraction of a flexed elbow with the forearm in full supination.
Classic history and presentation: Patients typically experience sudden anterior elbow pain at the antecubital fossa and may hear an audible pop or snap. Subsequently, patients may demonstrate weakness on flexion of the elbow or supination of the forearm against resistance. Bruising or ecchymosis at the medial arm or in the location of the antecubital fossa, with an associated reverse "Popeye" deformity of the arm / muscle, may be seen.
Prevalence: Although incidence is classically estimated at about 1.2 per 100 000 persons each year, more recent literature suggests the incidence of distal biceps tendon ruptures to be 2.55 of 100 000 persons per year.
- Age – Typically occurs in the fourth to sixth decades of life.
- Sex / gender – This complication occurs vastly more often in men, up to 96% of the time.
Pathophysiology: The pathophysiology of distal biceps rupture is likely the combination of two leading theories: impingement and hypovascularity. Mechanical impingement on the biceps tendon between the radioulnar joint during forearm rotation leads to microtrauma of the tendon. Furthermore, a watershed zone of vascularity within the tendon receiving its blood supply from the brachial artery and posterior interosseous recurrent artery is susceptible to hypovascularity. These two chronic, repetitive factors can leave the tendon weakened and susceptible to injury or rupture when an eccentric load is applied.
