Proximal Biceps Ruptures

Proximal biceps tendon rupture predominantly involves the long head of the biceps (LHB). It is frequently a degenerative process associated with chronic shoulder impingement and rotator cuff disease.

Pathophysiology:

• The LHB tendon intra-articular portion is vascularly compromised and subject to shear forces.
• Usually occurs at the proximal bicipital groove entrance or near the supraglenoid tubercle.
• "Autotenotomy": Spontaneous rupture often relieves the deep anterior shoulder pain of chronic biceps tendinitis.

Risk Factors:

• Age over 40 (degenerative changes)
• History of rotator cuff tears (supraspinatus/subscapularis)
• Smoking
• Corticosteroid injections (weakens collagen)
• Overuse (overhead sports like tennis, swimming, baseball)
• Anabolic steroid use (in younger weightlifters)

Natural History: The long head of the biceps often undergoes a process of inflammation (tendinitis) followed by degeneration (tendinosis) and eventual rupture. This "autotenotomy" can be the final stage of a painful process. Once ruptured, the irritating intra-articular portion of the tendon is no longer under tension, often leading to significant pain relief. However, the resulting weakness and deformity must be weighed against the risks of surgical reconstruction. The cosmetic deformity ("Popeye" sign) does not improve with time and is permanent unless surgically addressed.

The long head of biceps (LHB) tendon fails through a predictable degenerative cascade rather than a single traumatic event in most patients.

• Mechanical environment: The intra-articular LHB makes a near 90-degree turn at the rotator interval to enter the bicipital groove. This turn is a chronic shear and friction point ("pulley" zone).
• Vascular factors: The proximal intra-articular segment lies in a relative hypovascular watershed zone, limiting healing and predisposing to attritional degeneration.
• Degenerative sequence: Tenosynovitis (tendinitis) progresses to tendinosis with collagen disorganisation, then partial and finally complete rupture - typically near the supraglenoid tubercle or groove entrance.
• Impingement linkage: Subacromial impingement and rotator cuff disease accelerate LHB degeneration, which is why proximal rupture is a sentinel sign of cuff pathology over the age of 40.
• Instability mechanism: Because the transverse humeral ligament is reinforced by subscapularis fibres, a subscapularis tear allows the LHB to sublux/dislocate medially before it ruptures.
• "Autotenotomy": Once the tendon ruptures, the inflamed intra-articular pain generator is unloaded, which is why chronic anterior shoulder pain often improves after the rupture event.

Key Structures:

• Origin: Supraglenoid tubercle (40-60% from superior labrum).
• Transverse Humeral Ligament: Holds tendon in groove (continuation of subscapularis tendon).
• Bicipital Groove: Between greater and lesser tuberosities.
• Short Head: Originates from coracoid process (remains intact in LHB rupture).
• Insertion: Radial tuberosity (common tendon).

Blood Supply:

• Anterior circumflex humeral artery branches.
• Proximal intra-articular zone is relatively hypovascular ("watershed zone").

Function:

• Elbow Flexion: Secondary to brachialis.
• Forearm Supination: Primary supinator (with supinator muscle).
• Shoulder Stability: Depresses humeral head (minor role), anterior stabilizer.

Special Tests (Pre-rupture / Contralateral): Tests are often negative AFTER complete rupture.

1. Speed's Test: Pain with forward flexion against resistance (elbow extended, supinated).
2. Yergason's Test: Pain with supination against resistance (elbow 90 deg). Specific for groove pathology.
3. Ludington's Test: Hands on head, flex biceps. Palpate for absence of tendon (specific for rupture).

Note for Tenotomy: Immediate active ROM is allowed as tolerated. No specific restrictions other than pain.

Evidence summary (consolidated from Level I RCTs and meta-analyses):

• Functional scores equivalent — ASES, WORC and Constant-Murley scores do not differ between tenotomy and tenodesis in pooled Level I data.
• Popeye deformity is the one reproducible difference — roughly 23-33% after tenotomy vs 7-10% after tenodesis.
• Strength — most RCTs show no difference in elbow flexion or supination strength; only isolated trials show marginally higher supination strength after tenodesis (clinical relevance debated).
• Cramping — historically attributed to tenotomy, but high-level RCTs found cramping rates similar between groups.
• Trade-offs — tenotomy is faster with simpler rehab; tenodesis better preserves cosmesis at the cost of operative time, implant cost and the specific risks below.

The "Popeye" arm and acute anterior shoulder pain have a short but exam-relevant differential. The single most important distinction is proximal vs distal biceps rupture, because their management algorithms are opposite.

Global epidemiology

• Long head of biceps (LHB) pathology is found in a high proportion of rotator cuff tears at surgery; isolated LHB rupture in patients over 40 is widely regarded as a sentinel sign of cuff disease.
• Peak incidence is the 5th-6th decade, predominantly in men and manual or overhead workers.
• Distal ruptures are far rarer than proximal and occur in younger, often muscular men with sudden eccentric load.

Side-by-side guidance

Practice variation by resource setting

• High-resource settings: ready MRI access, arthroscopic suprapectoral or open subpectoral tenodesis with implants, formal physiotherapy pathways.
• Limited-resource settings: ultrasound or clinical diagnosis predominate; non-operative management and, when surgery is indicated, arthroscopic tenotomy (no implant cost, immediate rehab) are favoured. The functional equivalence shown in RCTs makes tenotomy a defensible, cost-effective default where implants are scarce.