Biceps Tendinopathy

What Is Biceps Tendinopathy?

Biceps tendinopathy is a painful condition of the long head of the biceps brachii tendon as it passes through the bicipital groove (intertubercular sulcus) of the humerus. It is a frequent cause of anterior shoulder pain, accounting for approximately 5% of shoulder pain in adults — although this figure likely underestimates the true prevalence, since biceps tendinopathy frequently coexists with other shoulder pathologies.

In most cases, biceps tendinopathy is not an isolated condition. It coexists with subacromial impingement syndrome in up to 95% of cases and with rotator cuff pathology in a significant proportion of patients. This occurs because the long head of the biceps tendon shares the subacromial space and is vulnerable to the same compressive mechanisms.

The long head of the biceps tendon originates at the supraglenoid tubercle and the superior glenoid labrum, traverses the shoulder joint, and emerges through the bicipital groove — a bony channel on the anterior humerus. The intra-articular portion and the transition zone into the groove are the most frequent sites of pathology.

Pathophysiology

The long head of the biceps (LHB) tendon has a complex anatomical course. It originates at the supraglenoid tubercle and superior labrum, traverses the glenohumeral joint in contact with the humeral head, and enters the bicipital groove — a bony channel formed by the greater and lesser tubercles of the humerus, covered by the transverse humeral ligament.

Tendinopathy results from a combination of extrinsic compression (by the coracoacromial arch in impingement syndrome, by osteophytes, or by the transverse ligament) and mechanical overload (activities involving repetitive shoulder flexion and supination). The most vulnerable portion is the transition zone between the intra-articular segment and the bicipital groove, where the vascular supply is most precarious.

Relationship with the Rotator Cuff

The close anatomical relationship between the LHB tendon and the rotator cuff explains why these pathologies frequently coexist. The subscapularis tendon forms the medial wall of the bicipital groove and, together with the supraspinatus tendon, anchors the biceps tendon in the groove (biceps pulley). Biceps pulley lesions — frequently associated with subscapularis tears — allow instability or medial subluxation of the biceps tendon, generating inflammation and pain.

Histopathologically, biceps tendinopathy follows the tendinosis model: it is not predominantly inflammatory but rather a degenerative process with disorganized collagen fibers, neovascularization, and failed repair. The term "tendinitis" (inflammation) is less precise than "tendinopathy" or "tendinosis" for describing most chronic presentations.

Symptoms

The cardinal symptom is anterior shoulder pain over the bicipital groove. Pain may radiate distally along the biceps muscle belly and, occasionally, proximally to the deltoid region. Activities involving shoulder flexion with the arm in supination tend to exacerbate symptoms.

Diagnosis

Diagnosing biceps tendinopathy combines clinical history (anterior shoulder pain exacerbated by flexion and supination activities) with provocative tests specific to the long head of the biceps tendon. Ultrasonography is the first-line imaging study, offering accessible, dynamic evaluation of the tendon in the groove.

Treatments

Conservative treatment is the first line for most cases of biceps tendinopathy, with satisfactory responses in 60-70% of patients. The approach combines relative rest with activity modification, progressive loading of the tendon (eccentric strengthening protocol), and concomitant treatment of associated pathologies (subacromial impingement, rotator cuff).

Progressive Loading Protocol

The central concept of modern tendinopathy treatment is progressive loading — gradual exposure of the tendon to mechanical stimuli that promote reorganization of collagen fibers and maturation of tendinous tissue. In biceps tendinopathy, this includes eccentric exercises of shoulder flexion (controlling the descent of the arm with light weight) and heavy slow resistance (HSR) for elbow flexion.

Supinator strengthening is a complementary strategy to offload the biceps: by strengthening the supinator muscle — which shares the supination function with the biceps — the demand on the biceps tendon during activities involving supination is reduced. This is particularly relevant in patients whose occupational or sporting activity involves repetitive supination.

Acupuncture

Acupuncture may contribute as an adjuvant to the progressive loading protocol in biceps tendinopathy, modulating pain and potentially favoring tendon repair. The approach combines local points over the bicipital groove with regional and distal points for neuromodulation.

The point LI-15 (Jianyu), in the anterior depression of the acromion, and LU-1 (Zhongfu), below the clavicle in the infraclavicular fossa, are relevant regional references. Ashi points directly over the bicipital groove — identified by guided palpation — allow precise needling in the peritendinous tissue. Ultrasonographic localization may increase precision in selected cases.

Electroacupuncture at frequencies of 2-4 Hz applied between points flanking the bicipital groove has been associated with the release of endogenous opioids. Preclinical studies in tendinopathy models suggest possible modulation of neovascularization, collagen synthesis, and the expression of nociceptive mediators (substance P, CGRP) in tendinous tissue — findings that have not yet been fully confirmed in human clinical studies and should be interpreted as mechanistic hypotheses.

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