BICEPS MUSCLE-TENDON RUPTURE Introduction Rupture of the biceps brachii muscle or tendon may occur in younger age groups due to high impact sports injuries. In older age groups the injury usually occurs due to degenerative changes in the tendon and lesser degrees of trauma. Most cases are proximal and involve the long head of the biceps muscle. Only occasionally does the distal attachment to the radial tuberosity rupture. Proximal ruptures result in surprisingly little functional loss, (due to preservation of the short head) and surgical repair is usually restricted to younger more active patients. Distal ruptures are more problematic and result in much greater disability and will usually require surgical repair. Anatomy At its proximal origin, the biceps brachii muscle has two tendinous insertions on the scapula from its long and short heads. ●

The short head arises from the coracoid process (with the coracobrachialis).

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The long head originates from the supraglenoid tubercle and passes over the humeral head within the capsule of the glenohumeral joint.

The 2 muscle bellies unite near the midshaft of the humerus and attach distally on the radial tuberosity. The distal tendon blends with the bicipital aponeurosis, which affords protection to structures of the cubital fossa. The biceps brachii receives its innervation from the musculocutaneous nerve (C5, C6). See also Appendix 1 below. Pathology Biceps muscle ruptures may occur:

1.

2.

Proximally: ●

About 95 % of cases are proximal ruptures, and most of these will be of the long head of the biceps

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Rarely it may occur at the short-head insertion on the acromion.

Distally: ●

The remaining ruptures (< 5 %) occur distally at the insertion on the radial tuberosity There is usually some degree of tendinitis, or degenerative changes within the tendon, that predisposes the patient to its rupture at this point.

Predisposing factors These include: 1.

2.

Age: ●

Age related avascular degeneration of the biceps tendon

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The most common age group for biceps ruptures is 40-60 years

Sporting related: ●

3.

In younger age groups rupture may be caused by sudden and violent muscle contraction, typically during sporting activities

Rheumatoid arthritis: ●

Tendon rupture due to chronic inflammation may occur in patients with rheumatoid arthritis.

Clinical features Proximal tendon ruptures: 1.

Onset: ●

2.

Usually patients will have sudden pain associated with an audible snap in the area of their anterior shoulder.

Pain: ●

Pain is usually not significant, and in fact some patients may experience pain relief after the rupture of an inflamed tendon!

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If pain persists following a proximal biceps tendon rupture, other causes of shoulder pain should be considered. These include rotator cuff bursitis, rotator cuff tears, or avulsion fractures around the shoulder.

3.

Deformity: ●

After the long head tendon ruptures the muscle retracts and patients may notice a bulge in their arm at the biceps muscle. This is the retracted muscle bunched up in the arm, and is sometime referred to as a “Popeye Muscle”, because the muscle appears more pronounced than normal. The long head contracts down toward the elbow, (as the glenoid attachment has been lost).

Typical deformity associated with a rupture of the long head of biceps. 1 4.

Disability: ●

Patients suffer surprisingly little loss of arm or shoulder function following a proximal biceps tendon rupture. This is because the muscle has two heads of origin.

When the long head ruptures, the short head still provides good functionality. 5.

Swelling and bruising: ●

May range from mild to severe in acute ruptures

Heavy bruising resulting from an acute rupture of the biceps tendon. 1 Distal tendon ruptures: 1.

Onset: ●

2.

Pain: ●

3.

The patient may hear and/ or feel a sudden snap and experience pain where the tendon rupture occurs near the elbow.

Distal biceps tendon rupture is characterized by sudden pain over the front of the elbow after a forceful effort against a flexed elbow.

Deformity: ●

The muscle belly contracts upward towards the shoulder, (as the radial attachment has been lost).

Typical deformity of the rare distal biceps tendon rupture, demonstrated in a 56 year old male who sustained a mild trauma to his left arm. Note the distal depression caused by the proximal retraction of the muscle belly. On the right the patient points his finger to a region of hematoma swelling. (Clinical photograph courtesy Dr Danny Feilizadeh).

4.

Disability: Patients who suffer a rupture of the distal tendon of biceps will suffer far more disability. There will be weakness of:

5.

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Elbow flexion

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Forearm supination

Swelling and bruising: ●

May range from mild to severe in acute ruptures.

Investigations Investigation is often not necessary; however imaging may be useful to: ●

Confirm the diagnosis in unclear situations

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Rule out alternative diagnoses

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Assess the extent of injury.

Ultrasound This is the most useful investigation for the assessment of biceps rupture MRI MRI provides the best anatomical definition of muscle and tendon, but is a much more expensive test than ultrasound and is rarely justified for the indication of biceps rupture alone. Management 1.

Analgesia: Give analgesia as clinically indicated ●

NSAIDS are commonly given Paracetamol or oxycodone are alternatives in those unable tolerate NSAIDS.

2.

3.

Immobilization: ●

An initial period of resting the limb in a board arm sling is useful for comfort.

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Vigorous mobilization that occurs too early may result in myositis ossificans and so should be avoided in the initial stages following acute injury.

Physiotherapy: ●

4.

Occupational therapy: ●

5.

Physiotherapy will play an important role in the longer term recovery of function, in cases that are treated both conservatively and operatively.

This may be necessary elderly patients.

Surgery: Proximal ruptures: ●

Patients do not usually notice any significant loss of arm or shoulder function following a proximal biceps tendon rupture.

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A slight bulge in the arm and some twitching of the retracted muscle are usually the most significant symptoms.

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Surgical repair of the proximal biceps tendon therefore is usually only considered in cases of younger patient more active patients.

Distal ruptures: ●

When the rare rupture occurs at the distal biceps tendon at the elbow, (where there is only one attachment), surgical repair is much more commonly needed.

Appendix 1 Anatomy of the biceps brachii muscle

Left Biceps Brachii muscle, (Gray’s Anatomy 1918) The Biceps brachii is a long ursiform muscle, placed on the front of the arm, and arising by two heads, from which circumstance it has received its name. The short head arises by a thick flattened tendon from the apex of the coracoid process, in common with the Coracobrachialis. The long head arises from the supraglenoid tuberosity at the upper margin of the glenoid cavity, and is continuous with the glenoidal labrum. This tendon, enclosed in a special sheath of the synovial membrane of the shoulder-joint, arches over the head of the humerus; it emerges from the capsule through an opening close to the humeral

attachment of the ligament, and descends in the intertubercular groove; it is retained in the groove by the transverse humeral ligament and by a fibrous prolongation from the tendon of the Pectoralis major. Each tendon is succeeded by an elongated muscular belly, and the two bellies, although closely applied to each other, can readily be separated until within about 7.5 cm. of the elbow-joint. Here they end in a flattened tendon, which is inserted into the rough posterior portion of the tuberosity of the radius, a bursa being interposed between the tendon and the front part of the tuberosity. As the tendon of the muscle approaches the radius it is twisted upon itself, so that its anterior surface becomes lateral and is applied to the tuberosity of the radius at its insertion. Opposite the bend of the elbow the tendon gives off, from its medial side, a broad aponeurosis, the lacertus fibrosus (bicipital fascia) which passes obliquely downward and medialward across the brachial artery, and is continuous with the deep fascia covering the origins of the Flexor muscles of the forearm Gray’s Anatomy 1918

References 1.

Fergusun D.G, Fodden D.I Accident and Emergency Medicine, Churchill Livingston, 1993

Dr J. Hayes Reviewed April 2013.