Distal Biceps Tendon Avulsions
Rupture of the distal tendon of the biceps brachii may result in functional deficits of forearm supination, strength, and endurance, as well as elbow flexion power. Traditional repair methods use two incisions to avoid injury to the posterior interosseous nerve (PIN) and to facilitate placement of sutures through bone drill holes. Radioulnar synostosis is a potentially serious complication of this technique, especially if the ulnar periosteum is exposed (Fig. 52–1). Repair via a single anterior incision has been reported but placement of bone drill holes is technically challenging and risks injury to the PIN.
Distal biceps tendon rupture that detaches the insertion of both heads of the biceps brachii and frequently tears the lacertous fibrosus, thereby completely eliminating the function of the muscle.
Distal biceps tendon rupture in the elderly and in less active people for whom conservative treatment may be preferred.
Mechanism of Injury
The history typically includes a sudden extension of the actively flexed and supinated elbow, usually during a heavy lifting episode. The patient reports a sharp pain with an associated tearing or popping sensation.
1. May note a proximal retraction of the biceps muscle.
2. Active elbow flexion should be tested and compared with the opposite side: asymmetry is evident with biceps rupture.
3. The biceps muscle belly may be displaced proximally and the tendon may be palpable under the skin.
4. Biceps tendon will no longer be taut and prominent in the antecubital fossa and may be palpable under the skin more proximally.
5. Intact lacertus fibrosis may become more prominent when the biceps is ruptured because of its altered function of transmitting the power of the biceps (Fig. 52–2).
6. Pain dissipates but patient notes persistent weakness and early endurance fatigue with supination (turning screwdrivers, doorknobs).
7. Lack of proximal-distal biceps movement on pronation-supination.
8. Supination and flexion strength are decreased when compared to the other side, and in the acute setting may be limited by guarding secondary to pain.
1. Magnetic resonance imaging (MRI) is generally not necessary for the diagnosis of a complete rupture; rather, the diagnosis will be apparent from the history and physical examination. MRI, however, has been shown to provide a precise diagnosis and may be useful in cases of partial biceps tendon rupture.
2. Radiographs may reveal a rare avulsion fracture of the bicipital tuberosity, but are typically normal.
Differential Diagnoses and Concomitant Injuries
1. Distal fracture—coronoid (ulna)
Preoperative Planning and Timing of Surgery
Early repair, within 2 to 3 weeks of the initial injury, is preferred. Repair is easiest at this time because there is diminished scarring that can obliterate the normally smooth intramuscular tunnel for the biceps tendon toward the tuberosity. Further delay allows muscular contracture, which increases the difficulty of primary reattachment without excessive tension and flexion of the elbow. Delay often requires free tendon grafts to permit attachment of the biceps tendon to the radius at the preferred 45 degrees of elbow flexion.
1. Statak 2.5 mm suture anchors
2. Power drill
3. Deep knee retractors