The bicep muscle has two tendons that attach proximally to the scapula (supraglenoid tubercle and coracoid process of the shoulder) and one tendon that attaches distally to the radius at the elbow (radial tuberosity). Proximal bicep tendon tears are more common than distal bicep tendon tears.
Bicep tendon tears are caused by a sudden forceful event (eg, lifting a heavy object) or forceful extension or twisting of the elbow. These tears typically occur when the tendon is already weakened by overuse (eg, as occurs with weightlifting), which can cause tendinitis and sometimes fraying of the tendon. In elderly patients, degenerative tendinosis, which weakens the biceps tendons, increases the risk of a tear. Other factors that can weaken a tendon may increase risk of tendon tears, but their contribution to bicep tendon tears has not been well-studied.
The injury that tore the bicep tendon may also damage other structures in the shoulder (eg, rotator cuff).
Bicep tendon tears may be partial or complete.
Symptoms and Signs
Bicep tendon tears cause sudden, severe pain either at the upper arm and shoulder or near the elbow, depending on the location of the tear. Pain is worsened by lifting or pulling. Other symptoms include bruising, swelling, and weakness. Also, the detached muscle may form a bulge in the arm (Popeye deformity).
Diagnosis
Bicep tendon tears can often be diagnosed based on the history and a physical examination. The examination and special tests (eg, hook test) can suggest which tendon is injured and whether the tendon is torn. For the hook test, the flexed elbow is supinated, and examiners attempt to hook their index finger under the intact biceps tendon from the lateral side. If the biceps tendon is torn (distal avulsion), there is no cordlike structure to palpate or hook.
Musculoskeletal ultrasonography is often used to examine the shoulder and is accurate for diagnosis of complete proximal bicep tendon tears. Ultrasonography is less useful for partial tears and distal bicep tendon tears.
MRI may confirm the diagnosis but is usually not needed.
Treatment
Treatment of distal bicep tendon tear is usually surgical repair as soon as possible.
Proximal bicep tendon tears are sometimes managed conservatively because if one of the two bicep tendons at the shoulder is intact, that tendon can maintain function.
However, surgery is often needed for repair of proximal tendon tears, especially when there are other shoulder injuries.
