Disorders of the proximal aspect of the long head of the biceps tendon include tendinopathy, subluxation or dislocation, and partial or complete tears; these occur from inflammation, instability, or trauma.16 The long head of the biceps tendon originates from the superior labrum and the supraglenoid tubercle on the scapula. As it exits the glenohumeral joint, it courses through the bicipital groove as it travels anterior and superior to the humeral head.16 Approximately 50% of the long head of the biceps tendon originates from the superior labrum. Forces applied tend to pull the labrum off the glenoid rim. Due to this anatomic association, tears of the superior labrum, known as SLAP (superior labrum anterior to posterior) lesions, are frequently found in conjunction with long head of the biceps tendon pathology. Injuries of one or the other structure may be difficult to distinguish, both clinically and operatively.
The biceps tendon may also become inflamed, may become partially displaced out of the bicipital groove, or may rupture altogether. (See chapter 271, "Shoulder and Humerus Injuries" for the approach to traumatic ruptures of the distal bicipital tendon.)
Bicipital tendinopathy may be due to inflammation (tendinitis) or collagen tears in or around the tendon (tendinosis) and may be acute or chronic. Tendinitis and tendinosis are difficult to distinguish clinically. Bicipital tendinopathy triggers intense and localized pain at the anterior aspect of the shoulder. Repetitive overhead arm motion may result in inflammation chronically or an acute SLAP lesion, particularly in athletes. Pain at rest, night pain, and pain on rotation are common. Dislocation or subluxation of the biceps tendon from the bicipital groove is painful and occurs medially or laterally, while complete dislocation is seen only medially and is associated with a subscapularis tear. Posterolateral instability is associated with a supraspinatus tear. Concurrent injury to the biceps reflection pulley is necessary for tendon dislocation in either direction.16
Partial or complete rupture is almost always proximal and is due to micro-tears and other age-related degenerative changes in this area of the tendon. In younger patients, mild trauma may cause complete rupture of the biceps tendon, which is heralded by an audible snap or pop followed by severe pain and deformity.
Palpation of the tendon within the bicipital groove reproduces the intense pain. Forearm supination, one of the main actions of the long head of the biceps, also reproduces pain, especially when resistance is applied. In assessing for instability, resisted forearm supination may cause palpable subluxation or a painful popping sensation as the tendon undergoes subluxation; these findings are classic but not common.
Because biceps tendon pathology is frequently associated with pathology of adjacent structures, clinical testing is often inconclusive and inaccurate.16 Many provocative tests to confirm the presence of pathology of the long head of the biceps or superior labrum have been described in the literature. Speed's test identifies tear or tendinitis of the long head of the biceps; flex the shoulder to 90 degrees with the patient's arm (elbow) fully extended and supinated. Provide downward resistance against shoulder flexion. Pain localized to the bicipital groove indicates a positive test. The Speed's test appears to have a sensitivity of 87% and a specificity of 80% for tear of the long head of the biceps.17
SLAP lesions or labral tears are complex, and a recent Cochrane review concluded that physical examination alone cannot be used as the sole basis by which to diagnose a SLAP lesion. The test most likely to help diagnose a SLAP lesion is the active compression test. To perform, have the standing patient flex his or her shoulder to 90 degrees, and then adduct 10 to 15 degrees medially and rotate fully, with elbow extended. The examiner stands behind the patient and applies a uniform downward force to the arm. This is repeated in full lateral position. A positive response is indicated by eliciting pain on the first maneuver, which is reduced or eliminated on the second maneuver; the test is 60% to 100% sensitive and 85% to 98% specific.17
In biceps tendon rupture, the classic finding is described as a "Popeye" deformity caused by distal contraction of the muscle belly. Supination is weak on muscle testing, but elbow flexion remains strong because of the presence of other intact elbow flexors (short head of the biceps and brachialis muscles).
Plain radiographs are generally unhelpful in diagnosing biceps tendon or SLAP lesions. MRI is also poor in diagnosing biceps tendon and SLAP lesions; magnetic resonance arthrography is preferable. In the hands of skilled operators, US is poorly sensitive but very specific in diagnosing disorders of the long head of the biceps. Arthroscopy is considered the gold standard, although recent studies have demonstrated poor intrarater reliability of arthroscopic diagnosis.18
Manage tendinitis and subluxation with brief use of a sling as needed for support and comfort, aided by analgesics, anti-inflammatory agents, application of ice several times daily, and elevation to reduce swelling. Prescribe early mobilization with stretching exercises and follow-up within 7 to 14 days with a primary care provider.
Although not commonly administered by emergency physicians, intra-articular injections of local anesthetic and steroid can improve symptoms. Intra-articular injections can relieve bicipital symptoms but may be ineffective if adhesions or synovitis prevent dispersal into the bicipital groove. Direct injection into the bicipital groove with US guidance may be an option for specialists if previous intra-articular injections have not worked.18 Bicipital tendinitis usually resolves with conservative therapy.
Reserve orthopedic consultation for those with tendinopathy associated with instability, partial rupture, or high-grade SLAP lesion or those failing to respond to a conservative treatment regimen. Surgical options include debridement, tenotomy, or tenodesis.18 Bicipital tendon rupture often requires surgical repair, so orthopedic consultation in 24 to 48 hours is best. Patients with suspected SLAP lesions or other mechanical proximal biceps injuries generally require arthroscopic or other surgical intervention when symptomatic.