Biceps pathologies

Biceps lesion

Definition

• An inflammatory tenosynovitis, most commonly affecting the tendinous portion of the long head of the biceps as it travels within the bicipital groove of in the proximal humerus¹
• The continuum of clinical pathology ranges from acute inflammatory tendinitis to degenerative tendinopathy
• Both the biceps and brachialis are the strongest flexors of the elbow, so a positive resistance tests implicates these two in particular (although many other muscles perform the same function but in a weaker sense)
  • Pain in shoulder indicates the biceps and not the brachialis
  • Resisted supination with elbow flexed is added to the consideration, if positive this also indicates the biceps is at fault

Causes

• Sports with overhead arm throwing functions such as ²
  • Baseball
  • Softball
  • Volleyball
  • Gymnastics
  • Swimming
• Occupational work with manual labor
• Can be seen in association with subscapularis injuries and tears
• Injury to shoulder and or neck is important, and any relevant surgical history

Localization

• Long head of biceps - intra-articular
  • If at this location, this will impinge the tendon during arm elevation giving a painful arc
• Long head of the biceps – sulcus/bicipital groove

Development

• Biceps tendinopathy begins with the early stages of tenosynovitis and inflammation secondary to ³
  • Repetetive traction
  • Friction
  • Shoulder rotation
• Inflammation develops early in the tendinous portion in the bicipital groove
• The tendon expands in diameter secondary to swelling and/or associated hemorrhage, further compromising the tendon as it becomes mechanically irritated in its confined space
• Preexisting rotator cuff pathology can directly compromise the biceps long head itself as it is a direct extension of the synovial lining of the glenohumeral joint
• As the injury develops, structures are affected in the following ways
  • Sheath thickening
  • Fibrosis
  • Vascular compromise
• The tendon undergoes degenerative changes, and associated scarring, fibrosis and adhesions eventually compromise the tendons mobility
• As a result, the tendon becomes “locked” in the groove, further exacerbating the potential points of traction and overall increases shear forces experienced by the tendon along its course
• In the end, the biceps long head tendon can eventually rupture at its origin near the superior glenoid tubercle, or as it exits the bicipital groove near its musculotendinous junction

Indications

• Gradual onset of anterior shoulder pain experienced usually at the mid-arm
  • The pain is usually at the anterior aspect of the shoulder ^{4 5 6}
• Overhead activities provoke symptoms
• Pain radiating from shoulder down the anterior arm
• Pain at rest
• Pain at night
• Snapping tendon
  • During certain shoulder movements a palpable snap is present, typically in throwing athletes

Examination

• Resisted flexion of elbow – painful
• Resisted flexion of the shoulder with the elbow slightly flexed and forearm supinated is painful (Speed test)
• Supination of elbow – painful
• Resisted adduction – painful
  • Becomes painless if performed with elbow flexed due to less stretch on muscle and tendon
  • Only painful if intra-articular lesion
• Painful arc
  • Indicates the lesion is at the intra-articular part of the tendon becoming impinged under the acromion
  • Only present in intra-articular lesion
• Palpation
  • Only possible if the lesion is in the sulcus
    • In this case the palpation over the bicipital groove is painful

Additional functions

• The long head of the biceps has a role in the dynamic stability of the shoulder joint by stabilizing the shoulder, other studies have also refuted the theory so it remains controversial ^{7 8}
• More recent studies show that the biceps brachii long head is thought to enhance dynamic stability of the shoulder but only within the first 30° of elevation of the arm⁹

Considerations

• Pressure and strain on the glenoid part of the biceps is strongest in an abducted and overhead position
• The tendon of the long head of the biceps has a passive stabilizing role in the shoulder, its role is considered controversial in its ability to maintain dynamic stability of the shoulder
  • https://www.ncbi.nlm.nih.gov/books/NBK533002/
  • In most healthy patients the long head of the biceps tendon plays a negligible role in the dynamic stability of the shoulder

Biceps rupture

Localization

• Usually at the proximal part of the long head of the biceps
• Distal ruptures happen but are rare, may be seen in younger athletes often a result of local direct trauma

Causes

• Degeneration over time as a result of wear and tear

Indications

• Male patients over the age of 50 are more common of those suffering from this ailment
  • Other studies show that injury usually happen between the age of 35-54
  • Crack or tear may be heard at the moment of the tear
  • Some temporary pain is felt in the upper arm
  • A clear prominence may be seen especially if the patient is actively trying to flex the biceps

Examination

• No weakness is usually felt
  • Due to brachialis compensating for the weakness of the biceps
  • The biceps is considered a strong forearm supinator but a weak elbow flexor ¹⁰
  • There is a very prominent and palpable sign of retraction of the biceps muscle belly (popeye deformity) ¹¹