Biceps Tendon Subluxation

What is biceps tendon subluxation?

The biceps muscle attaches to bone via tendons; two at the shoulder and one in the elbow. At the shoulder, one of the attachments is known as the “long head,” a thin tendinous structure that runs in a groove at the front of the shoulder before entering the shoulder joint. The groove is bordered on three sides by bone (the “bicipital ridge”), with a “roof” covered by the transverse humeral ligament.

Occasionally, the soft tissue restraints that maintain the position of the long head of the biceps tendon within the groove can be injured, allowing the tendon to sublux, or partially dislocate in and out of its groove. This occurrence is often associated with a partial or complete tear of the subscapularis tendon, the rotator cuff tendon in the front of the shoulder.

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How does biceps tendon subluxation occur?

Subluxation often occurs due to degenerative failure of the upper portion of the subscapularis tendon of the rotator cuff.  Rarely, acute traumatic injury can compromise the tendon sheath over the groove, allowing the tendon to become unstable.

What increases the risk?

  • Contact sports, throwing sports, weightlifting and bodybuilding
  • Heavy labor
  • Poor physical conditioning (strength and flexibility)
  • Inadequate warm-up before activity

What are the symptoms of biceps tendon subluxation?

  • Mechanical symptoms such as a “clunk” when rotating the arm inward or outward.
  • Pain or discomfort in the front of the shoulder; pain may be referred to the biceps muscle
  • Symptoms associated with pathology of the subscapularis tendon, including pain in the front of the shoulder and pain with internal rotation (placing the hand behind the back)

How is biceps tendon subluxation diagnosed?

Physical exam findings that may be suggestive of long head biceps tendon pathology (either subluxation or tendon tearing) include tenderness along the bicipital sheath, a positive “Speed’s Sign,” and pain with internal rotation.

A specific diagnostic finding includes actual translation of the biceps tendon outside its sheath.  This translation can be elicited by having the patient actively supinate their forearm (turn their palm up) while keeping his or her elbow at their side.  The feeling of a clunk (the tendon slipping over the groove) is diagnostic.  This finding is very uncommon due to the depth of the tendon within the groove.

Are any special tests used to diagnose biceps tendon subluxation?

MRI allows for visualization of the long head of the biceps tendon.  Abnormalities seen may include degenerative changes and splits within the tendon, and, in the case of subluxation, displacement from its normal position within the bicipital groove.  This displacement indicates pathology and tearing of the upper subscapularis tendon, which serves as a restraint in the biceps tendons’ normal course. However, MRI will not detect subluxation that occurs dynamically, as MRI is performed as a static study.

Ultrasound may provide a dynamic means by which long head biceps instability is detected.  While the ultrasound probe is placed directly over the bicipital groove, the patient’s shoulder is actively and passively moved, allowing the physician to directly visualize changes in the biceps tendon’s position.

How is biceps tendon subluxation treated?

Treatment depends upon the degree of impairment and associated symptoms.  Treatment is often the same as that for long head biceps tendon pathology (degeneration and tears).  Conservative treatment consists of activity modification, anti-inflammatory medication and ice to relieve the pain, followed by stretching and strengthening exercises.

Surgical treatment should focus on concomitant issues such as rotator cuff or labral pathology. The most common surgical technique used to address subluxation is known as “tenodesis” in which the long head biceps tendon is stabilized within the groove. Tenodesis may involve either arthroscopic or open removal of a portion of the long head of the biceps tendon proximal to (above) the area of instability, and direct reattachment using drill holes, suture anchors, or sutures into the bone or soft tissue.

When can you return to your sport/activity?

Isolated surgical tenodesis may permit return to upper extremity activities as early as three to four months post-operatively.  Tenodesis in association with subscapularis and/or rotator cuff tendon tears require six months before return to unrestricted upper extremity function.

How can biceps tendon subluxation be prevented?

  • Subluxation is often due to degenerative changes and tearing of the upper subscapularis tendon, or from acute trauma, neither of which can be completely prevented.