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 (about half the diameter of the little finger) 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.”
Infrequently, the soft tissue restraints that maintain the biceps long head tendon position within the groove can be injured, allowing the tendon to sublux, or partially dislocate in and out of its groove. This rarely occurs without other shoulder problems. It is most 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 most commonly 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 practice or play
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, often referred to the biceps muscle.
- Symptoms due to pathology within the tendon of the subscapularis, 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?
Because it is so uncommon, there are no physical exam tests, which accurately identify this condition. Physical exam findings that may be suggest long head biceps pathology, either subluxation or tendon tearing, include tenderness along the bicipital sheath, a positive “Speed’s Sign,” pain with internal rotation.
Specific diagnostic finding would be actual translation of the biceps tendon outside its sheath. This has been described as elicited by having the patient actively supinate their forearm (turn their palm up) with the elbow maintained at their side. The feeling of a clunk or actual tendon slipping over the groove is diagnostic. Having said that, this finding is very uncommon because of the depth of the tendon’ position within the groove.
Are there any special tests?
MRI imaging permits visualization of the long head of the biceps tendon. Abnormalities can include degenerative changes and splits within the tendon, and, in the case of subluxation, displacement out of its normal position within the bicipital groove. When this occurs, it reflects pathology and tearing of the upper subscapularis tendon, which serves as a restraint in the biceps tendons’ normal course.
MRI, however, will not detect subluxation that occurs dynamically, because the test is performed with the arm positioned at the side of the body.
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, directly visualizing changes in the biceps tendons position.
How is biceps tendon subluxation treated?
Treatment depends upon the degree of impairment and associated problems. Because it is so uncommon, treatment is usually the same as that for long head biceps tendon pathology (degeneration and tears). Initial non-operative treatment consists of medication and ice to relieve the pain, stretching and strengthening exercises, and modification of provocative activities that cause symptoms.
In cases of refractory symptoms, or in those patients undergoing surgical treatment for associated problems (such as rotator cuff tendon repairs, or repairs of the upper border of the subscapularis tendon tears), operative repair includes several options. The most common is known as “tenodesis” in which the long head biceps tendon is stabilized within the groove, using a variety of techniques.
The most common involves either arthroscopic or open removal of a portion of the long head proximal to (above) the area of instability, and direct reattachment using drill holes, suture anchors or sutures into the bone or soft tissue. Surgical tenodesis must be accompanied by attention to any other torn tissues. Although direct repair or reconstruction of the overlying transverse humeral ligament seems logical, the success with this approach has been limited, and it is rarely undertaken.
What are the complications of treatment?
- Possible complications of non-operative treatment include persistent pain and impairment.
- Possible complications of operative treatment include ongoing symptoms, failure of the tenodesis and limitations in recovery due to surgery for associated pathology (such as repair of a subscapularis tendon tear).
When can you return to your sport/activity?
Isolated surgical tenodesis may permit return to upper extremity activities as soon as three to four months. Tenodesis in association with subscapularis and/or rotator cuff tendon tears takes longer, and may require six months before return to full unrestricted upper extremity function.
How can a biceps tendon subluxation be prevented?
- Subluxation is usually due to degenerative changes and tearing of the upper subscapularis tendon, or from acute trauma, neither of which can be effectively prevented.