What is a Biceps Muscle?
The biceps muscle is located in the front of the upper arm. It is attached at its upper end to bones in the shoulder and at its lower end to a bone in the upper forearm, just beyond the elbow joint. Thus contraction of the biceps muscle will have an effect on either shoulder or elbow function or both.
The biceps starts at the shoulder in the form of two rope-like tendons. One biceps tendon is attached to the coracoid process of the scapula at the front of the shoulder (Short Head of Biceps). The other biceps tendon (Long Head of Biceps Tendon) is attached to the top of the shoulder socket, within the shoulder joint. It then passes over the top of the head of the humerus and enters a groove at the front of the upper humerus. Both tendons continue in to the upper arm gradually changing in to fleshy muscles as they do so. The two muscle components blend together, then narrowing down to a single tendon at the lower end of the biceps muscle (Distal Biceps Tendon).
What is a Biceps Tendon Rupture?
Biceps tendon rupture in the context of shoulder problems refers almost exclusively to rupture or tearing of the Long Head of the Biceps Tendon. The mechanical configuration of the biceps tendon makes it susceptible to rupture. Tearing most often occurs in the substance of the tendon as it passes through the bicipital groove of the humerus. Less often it may tear away from its bony attachment within the shoulder joint. Rupture of the Short Head of Biceps Tendon is extremely rare.
Causes of Biceps Tendon Rupture
The Long Head of biceps tendon slides backwards and forwards in the groove at the front of the humerus (Bicipital Groove) as the shoulder moves through its range of motion. The tendon is also subject to significant load when performing heavy physical tasks that require forceful contraction of the biceps muscle. There may be abrasion of the tendon as it slides in the bony groove.The quality and strength of the tendon may also deteriorate with age. All of these factors may lead to the biceps tendon giving way. That can occur gradually as a degenerative process due to micro stresses on the tendon over a lifetime. It may occur more suddenly when high physical load is applied to the biceps.
Symptoms of Biceps Tendon Rupture
The common symptoms of a biceps tendon rupture include:
- Sudden sharp pain in front of shoulder and upper arm
- Lower grade preceding soreness
- Audible popping sound at the time of rupture
- Visible deformity of the biceps muscle – “Popeye” Sign
- Bruising in biceps region
- Biceps muscle weakness
Diagnosis of Biceps Tendon Rupture
You may have noticed some of the above symptoms. Your description of the events may help to make the diagnosis obvious. The clinical deformity of the muscle may not be immediately apparent. However the abnormal shape of the muscle may be made more obvious by resisted contraction of the biceps muscle. The bruising may also not appear for several days.
More often than not the diagnosis is obvious from the symptoms and clinical signs. However in case of doubt an Ultrasound test or MRI Scan may be helpful. Biceps tendon rupture sometimes occurs in association with rotator cuff tendon disease. These tests may help to evaluate any such associated rotator cuff issue.
Biceps tendon rupture especially in older patients may not require surgery. Pain and bruising settles over several weeks. Rest, icing, and medication may help. There may be no or minimal residual symptoms. The “Popeye” appearance of the muscle will persist but there may be no pain, no obvious weakness, and normal shoulder function.
If the rupture has been preceded by some niggling pain due to degeneration of the tendon, those symptoms may actually disappear after the tendon finally gives way.
Younger patients may be more aware of ongoing issues such as a cramping sensation in the biceps muscle and a sense of weakness. This is particularly the case for patients who work in physical occupations. The need for a surgery is more likely in this group.
Surgery will require a small incision at the front of the mid upper arm. This allows the tendon which will have dropped down in to that area to be located. A second short incision is made at the front of the shoulder. The tendon can then be passed from the lower to the upper incision. The biceps tendon is not repaired as such. Rather, the retrieved tendon is secured to the bony groove at the front of the humerus. This restores a better appearance of the muscle and provides a secure anchor point for the muscle to act with normal strength. Surgery is ideally performed within a week or two or the rupture. Beyond that time frame the muscle tissue scars and shortens making it difficult to mobilise the tendon back to the bicipital groove.
Given that there is a risk of the tendon tearing away after surgery use of a sling is initially required. Resisted contraction of the biceps muscle needs to be avoided for approximately 6 weeks. It may take the tendon up to 3 months from the time of surgery to reach peak strength.