As its name suggests, the biceps muscle consists of two muscle heads (Latin ‘Bi’ for two). It has two tendons (short and long), each of which originates at a different point on the scapula. The long biceps tendon originates at the upper glenoid rim of the shoulder joint, passes through a pit in the humerus (sulcus bicipitalis), and finds its base at the radius. The biceps functions as an arm flexor muscle and is the most critical external rotator of the forearm when the elbow is flexed (supinator, e.g., when tightening a screw).
The long biceps tendon can be affected by several health problems.
- SLAP lesion (tear at the origin)
- Tendinopathy/tendinitis (inflammation of the tendon)
- Tendon instability (subluxation of the tendon inward)
- Long biceps tendon tear (proximal or distal)
If there is damage to the long biceps tendon, the affected person usually experiences pain in the front shoulder area. Activities distant from the body and overhead work with weights are often painful, e.g., when trying to grab a bag from the back seat of a car or when using heavy tools overhead. Mobility and strength are usually not affected.
In ultrasound, fluid accumulations (inflammatory reactions) are easily recognizable because, typically, no effusions are found on the biceps tendon. Fluids and instability are easily visible on ultrasound, primarily if the examination is performed dynamically. The patient is asked to perform specific movements.
Here one can determine where the biceps tendon migrates, whether it remains stable or is slipping away from the sulcus bicipitalis.
Arthro-MRI/arthrography (using contrast agents) shows the tendon’s position and whether it is dislocated or at its regular place. This examination is done in a complete resting position. If the tendon is subluxated inwards (medially), this can be assessed here. This diagnostic procedure is also used to classify a SLAP lesion. A contrast agent is injected into the joint to see if the agent migrates into the tear/rupture (resulting gap).
Where inflammation or irritation has developed, drug treatment can provide relief. High-dose NSAIDs are used to try to inhibit inflammation. Such drugs can be administered for 10 to 14 days. In most cases, patients also receive gastric protection.
If such therapy does not work, cortisone injections can still be administered. Cortisone is beneficial due to its anti-inflammatory effect and ability to break the cycle of pain-friction-swelling, pain-friction-swelling, and so on. If non-surgical interventions prove unsuccessful, surgery can be performed using a minimally invasive procedure (arthroscopy). In patients who have experienced a SLAP lesion due to trauma rather than degeneration or wear, surgery (fixation) can be performed.
Once symptoms (instability, irritation, etc.) turn chronic, and no treatment is effective, there is an option to dissect this tendon. There are two options to perform this transection. Tenotomy is called the dissection without fixation of the tendon. Although the long tendon of the biceps is being dissected, the function of the muscle continues to be maintained by the short biceps tendon. This is similar, for example, to the removal of the appendix. Although the appendix has been removed, the function of the intestine is not affected. The other option is called tenodesis. In this case, the tendon is detached and reattached at a different location on the humerus.
There are no clear advantages of one option over the other. Functionally, both are comparable. In some cases where a tenotomy is performed, a muscle bulge may develop that is larger than on the healthy side. This is also called a Popeye’s sign (dumpling on the upper arm).
If a spontaneous tear of the long biceps tendon occurs, it is also possible to consider simply leaving the tendon in place or performing a tenodesis.
The biceps tendon can also tear in or out at the radius (distal to the body). In this case, refixation of the tendon at its attachment point is usually performed to restore strength for external rotation and flexion.