Biceps Tendon Rupture

Biceps tendon rupture occurs at the proximal end (long head, about 90 to 96%) or the distal end (at the radial tuberosity, about 3 to 10%). The two behave very differently.

Proximal rupture happens in people over 50 with chronic tendinopathy or rotator cuff disease, often with minor load. The short head and brachialis preserve elbow flexion, so loss of strength is about 10 to 20% in elbow flexion and 20% in supination.

Distal rupture has an incidence of about 1.2 in 100,000 a year, with a strong male predominance, ages 40 to 60, in the dominant arm. The mechanism is a sudden eccentric extension force on a flexed elbow. Risks are smoking, anabolic steroid use, fluoroquinolone exposure and chronic tendinopathy. Untreated, it loses up to 30 to 40% of flexion strength and 40 to 50% of supination strength, and endurance falls further.

Tears are partial or complete. Delay beyond 4 to 6 weeks causes tendon retraction and scarring, which turns direct repair into reconstruction.

• A sudden pop with pain, then bruising along the arm
• Proximal: a Popeye bulge in the distal biceps, minor weakness, and cramping with use
• Distal: pain and a gap in the antecubital fossa, bruising, a muscle belly that has migrated proximally, and weak supination (more than flexion)
• Hook test: with the elbow flexed to 90 degrees and the forearm supinated, the examiner cannot hook an index finger under the lateral edge of the intact distal tendon. Sensitivity and specificity near 100%.
• Red flags: numbness over the lateral forearm (lateral antebrachial cutaneous nerve), a pulsatile mass or ischemia (brachial artery), tense swelling, open injury, and bilateral rupture with systemic disease

• Clinical diagnosis (the hook test for distal rupture).
• Ultrasound: an empty groove (proximal) or a retracted stump and a missing distal insertion, with dynamic assessment in supination and pronation.
• MRI (elbow flexed, shoulder abducted, forearm supinated) for partial distal tears, bursitis and for cuff tears in proximal rupture.
• Radiographs of the elbow for avulsion and bicipital tuberosity changes. Shoulder films for associated degeneration.

Differentials: partial tear, biceps tendinopathy, bicipital bursitis, brachialis tear, cuff tear, pronator teres strain.

Proximal rupture:

• Non-operative for most: sling for 1 to 2 weeks, ice, paracetamol 1 g orally every 6 hours, ibuprofen 400 mg orally every 8 hours with food for up to 7 days, then physiotherapy.
• Surgery (tenodesis) for young manual workers, athletes, patients concerned about appearance or cramping, and when a cuff repair is planned. Techniques: subpectoral tenodesis with an 8 mm interference screw or suture anchors.

Distal rupture, complete:

• Acute repair within 2 to 3 weeks (up to 6 weeks) in active patients.
• Single incision repair with a cortical button or suture anchors, or two incision repair with transosseous fixation. Pass the tendon in the correct position to preserve supination.
• Chronic ruptures: reconstruction with Achilles allograft or semitendinosus autograft.
• Non-operative care only for elderly, low demand patients or those unfit for surgery.
• Cefazolin 2 g IV before incision (3 g if over 120 kg).
• Postoperative: posterior splint at 90 degrees for 1 to 2 weeks, hinged brace with progressive extension over 6 weeks, active motion from week 2 to 6, strengthening from week 8 to 12, unrestricted use at 4 to 6 months.

Partial distal tear: rest, splint for 2 to 4 weeks and graded strengthening. Repair when symptoms persist for 3 to 6 months. Avoid corticosteroid injection.

Complications: lateral antebrachial cutaneous neuropraxia (up to 20 to 40% with single incision), posterior interosseous nerve injury (2 to 5%), heterotopic ossification and radioulnar synostosis (higher with two incisions), re-rupture (2 to 5%) and stiffness.

Follow up at 2 and 6 weeks, 3 and 6 months. Counsel on smoking cessation and avoidance of heavy lifting until the repair has healed.