The biceps consist of two heads, which are sometimes referred to as muscle bellies. Each head has its own proximal tendon. Both heads join at the middle of the arm to form a single distal tendon which inserts into the radius of the elbow.
Each head has different qualities, for example the short head is more robust in comparison to the long head of biceps. It originates at the chest wall, and it plays a significant role in the proper functioning of the biceps muscle.
The long head forms around the top of the shoulder (glenoid) from a long tendon that is attached to the socket. It can be seen running through the shoulder and out to the upper arm, before joining with the short head of biceps in an area known as the muscle belly. The long head of biceps is not essential for proper shoulder function except for people who are required to participate in heavy lifting, repetitive actions and overhead lifting on a regular basis.
The long head of biceps tendon is prone to biceps tendonitis and instability. Tendonitis is usually characterised by anterior shoulder pain, which may radiate down the biceps muscle.
In around 5% of cases, the condition can be labelled primary (e.g. bicipital groove inflammation observed with no further associated shoulder pathology). More commonly, it can be labelled secondary to another shoulder pathology (for example a rotator cuff tear) which has caused the tendon to become frayed and damaged, resulting in inflammation and pain.
When the bicepital pulley and subsequent subluxation of the tendon is disrupted, bicepital instability occurs. Eventually, the tendon will become dislocated and retreat into the subscapularis muscle (also known as anterior rotator cuff muscle). In the process, the subscapularis muscle can become damaged. Symptoms of biceptal instability are much the same as those for bicipital tendonitis, but in many cases there is a signature clicking sound which occurs when the tendon subluxes or dislocates, and this can be quite painful.
Treatment is first focussed on non-operative measures including the use of anti-inflammatory medications, rehabilitation programmes and corticosteroid injections. Rehabilitation programmes should be focussed on coexisting shoulder pathology. If there are no signs of improvement and symptoms still persist, it may be necessary to begin operative treatment. This will involve releasing the biceps tendon at the top of the shoulder, before fixing it into the bicipital groove through the use of an interference screw. This procedure is usually referred to as biceps tenodesis, and in most cases it can be performed entirely arthroscopically or arthroscopically assisted. This allows other associated shoulder pathology (if present) to also be repaired. Upon completion of surgery, rehabilitation can take up to 6 months.
Patients who are older or less active usually have the biceps removed from the shoulder. This procedure is referred to as biceps tenotomy. This will result in the long head of biceps becoming scarred up slightly below the shoulder, but the short head of biceps will remain in its original form to retain optimal bicep function. This procedure has a much shorter and easier recovery process than biceps tenodesis, and the only mark left behind is usually a cosmetic deformity around the upper arm.
In many cases, non-operative treatment of biceps instability is ineffective. Some patients may wish to try it, but in many cases they will remain symptomatic. It is important to keep in mind that damage to the subscapularis muscle is often progressive, so it is usually recommended that most patients have a biceps tenodesis and subscapularis repair done as soon as possible after examination. This can usually be performed arthroscopically.