15 The upper arm and elbow

Apart from injury, disorders of the upper arm and elbow region are generally straightforward and present few special problems. They conform to the general descriptions of bone and joint diseases that were given in Part 2. Thus the humerus is subject to the ordinary infections of bone, and occasionally to bone tumours – especially metastatic tumours. The elbow is liable to every type of arthritis, none is particularly common though rheumatoid arthritis is commoner than osteoarthritis. After the knee, it is the joint most often affected by osteochondritis dissecans and loose body formation. The ulnar nerve lies in a vulnerable position at the back of the medial epicondyle, and the possibility of impairment of nerve function complicating disease or injury of the joint should always be remembered. Replacement arthroplasty of the elbow is undertaken increasingly, but compared with those of hip and knee arthroplasty the results still leave much to be desired, especially from the point of view of the longevity of the new joint.

SPECIAL POINTS IN THE INVESTIGATION OF UPPER ARM AND ELBOW SYMPTOMS

History

The interrogation follows the usual lines suggested in Chapter 1. It is important to ascertain the exact site and distribution of the pain, and its nature. Pain arising locally in the humerus is easily confused with pain arising in the shoulder, which characteristically radiates to a point about half-way down the outer aspect of the upper arm. Elbow pain is localised fairly precisely to the joint, though a diffuse aching pain is often felt also in the forearm. When the ulnar nerve is interfered with behind the elbow the symptoms are mainly in the hand.

In the elbow, a history of previous injury, perhaps long ago in childhood, is often relevant. Injuries in this region are notoriously liable to have late effects in the form of impaired movement, deformity, arthritis, loose body formation, or interference with the ulnar nerve.

Exposure

The whole length of the upper limb must be uncovered. The opposite limb must be similarly exposed for comparison.

Steps in routine examination

A suggested plan for the routine clinical examination of the upper arm and elbow is summarised in Table 15.1.

Table 15.1 Routine clinical examination in suspected disorders of the upper arm and elbow

1. LOCAL EXAMINATION OF THE ARM AND ELBOW
Inspection	Power
Bone contours and alignment	Flexors
Soft-tissue contours	Extensors
Colour and texture of skin	Supinators
Scars or sinuses	Pronators
Palpation	Stability
Skin temperature	Lateral ligament
Bone contours	Medial ligament
Soft-tissue contours	The median nerve
Local tenderness	Sensory function
Movements (active and passive)	Motor function (opponens action)
Humero-ulnar joint:	Sweating
Flexion	The radial nerve
Extension	Sensory function
Radio-ulnar joint:	Motor function (extension of wrist, thumb, and fingers)
Supination	The ulnar nerve
Pronation	Sensory function
? Pain on movement	Motor function
? Crepitation on movement	Sweating
2. EXAMINATION OF POTENTIAL EXTRINSIC SOURCES OF ARM PAIN
This is important if a satisfactory explanation for the symptoms is not found on local examination. The investigation should include: 1 the neck, with the brachial plexus 2 the shoulder

3. GENERAL EXAMINATION General survey of other parts of the body. The local symptoms may be only one manifestation of a widespread disease

Movements at the elbow

The elbow joint has two distinct components: the hinge joint between the humerus above and the ulna and radius below, allowing flexion–extension movement; and the pivot joint between the upper ends of the radius and ulna, allowing rotation of the forearm. It should be remembered that free rotation of the forearm is dependent not only upon an intact superior radio-ulnar joint: it demands also free mobility between the radius and ulna throughout their length, and distally at the inferior radio-ulnar joint. Flexion–extension: The normal range is from 0 to 155 ° (0 = anatomical position, with the arm straight). Supination–pronation: Rotation movements must be tested with the elbow flexed to a right angle, to eliminate rotation at the shoulder (Fig. 15.1A). The normal range is 90 ° of supination (palm up) and 90 ° of pronation (palm down) (Fig. 15.1B). If the range of rotation is restricted possible causes must be sought in the forearm and wrist as well as in the elbow.

Fig. 15.1 A Examining rotation of the forearm. The elbow is flexed 90 ° to eliminate rotation at the shoulder. B Range of supination and pronation of the forearm.

The ulnar nerve

Because of the vulnerability of the ulnar nerve in its course behind the elbow, tests of ulnar nerve function should be carried out as part of the routine examination of the elbow. Examine for sensibility in the little finger and medial half of the ring finger, and test the ulnar-innervated small muscles of the hand for wasting or weakness: a simple test is to ask the patient to spread the fingers and to bring them together again forcibly, to prevent a card gripped between the middle and ring fingers from being withdrawn. Note whether the skin in the territory of the ulnar nerve sweats equally with the rest of the hand.

The median and radial nerves

The integrity of the median and radial nerves should also be tested. Criteria of integrity of the median nerve are volar sensibility in the lateral three and a half digits, and active power of opposition of the thumb. Integrity of the radial nerve is demonstrated by ability to dorsiflex the wrist and to extend the digits at the metacarpo-phalangeal joints. A distal lesion, affecting the posterior interosseous division of the nerve, may leave wrist extension intact while impairing extension of the digits.

Imaging

Radiographic examination. Radiographs of the humerus must always include antero-posterior and lateral projections, and they should take in both the shoulder joint and the elbow.

Routine radiographs of the elbow comprise an antero-posterior projection with the elbow straight and a lateral projection with the joint semiflexed. In special circumstances additional oblique or tangential projections may be helpful. A radiograph of the forearm bones and of the inferior radio-ulnar joint is also required when rotation of the forearm is impaired.

Other imaging techniques. Radioisotope scanning, CT scanning, and MR imaging may all be helpful in appropriate circumstances.

Extrinsic sources of pain in the upper arm

Pain in the upper arm is commonly referred from a lesion elsewhere—particularly from the shoulder, and from the neck when the brachial plexus or its roots are involved. Shoulder pain usually radiates from the tip of the acromion process to about the middle of the outer aspect of the arm, but it does not extend below the elbow. In contrast, nerve pain from interference with the brachial plexus often extends throughout the length of the arm and forearm into the hand and fingers; and frequently there is accompanying paraesthesiae in the form of tingling, numbness, or ‘pins and needles’.

DISORDERS OF THE UPPER ARM

ACUTE OSTEOMYELITIS (General description of acute osteomyelitis, p. 85)

Osteomyelitis is less common in the upper limb than in the lower. Nevertheless the humerus is a well’recognised site of haematogenous infection – especially its upper metaphysis.

Pathology. Except in time of war the humerus is seldom infected directly by organisms introduced from without, for compound fractures are rare. Infection is usually haematogenous, from a focus elsewhere in the body. This type of infection occurs mainly in children, and it usually begins in a metaphysis of the bone – more often the upper metaphysis than the lower. Since both the upper and the lower metaphyses are partly enclosed within the capsule of the shoulder and of the elbow respectively, a metaphysial infection is liable to spread directly to the adjacent joint, causing pyogenic arthritis (see Fig. 7.2).

Clinical features. There is constitutional illness, with pyrexia. Locally, there is severe pain at the site of infection. On examination there is intense and welllocalised tenderness over the affected area – usually near one end of the bone. Later, there may be swelling and increased warmth, and a fluctuant abscess may form. The adjacent joint is commonly swollen from an effusion of fluid (‘sympathetic’ effusion), even if the joint itself is not involved in the infection. In the absence of joint infection, however, movements are restricted only slightly, if at all.

Imaging. Radiographs do not show any abnormality at first. After about two weeks there are often localised rarefaction and subperiosteal new bone formation (Fig. 15.2), but these changes may be slight at first. Radioisotope scanning shows increased uptake in the affected area.

Fig. 15.2 Acute osteomyelitis of upper end of humerus. Radiograph 4 weeks after onset showing marked rarefaction of the bone, with patchy areas of destruction and much subperiosteal new bone formation.

Investigations and treatment are the same as for acute osteomyelitis elsewhere (p. 89).

CHRONIC OSTEOMYELITIS (General description of chronic osteomyelitis, p. 90)

As in other bones, chronic pyogenic osteomyelitis of the humerus is nearly always a sequel to acute osteomyelitis that has been neglected or has responded poorly to treatment. The bone is thickened, often throughout its whole length, and there may be a persistent or intermittent purulent discharge from a sinus, or recurrent flare-ups with local pain and induration. Radiographs show irregular thickening with patchy areas of sclerosis and cavitation, and sometimes a sequestrum.

Treatment was described on page 91.

TUMOURS OF BONE

Benign tumours (General description of benign bone tumours, p. 106)

Osteochondroma, osteoid osteoma, and giant-cell tumour can all affect the humerus but none are particularly common at this site.

Giant-cell tumour is uncommon in the humerus, but when it does occur the usual site is at the upper end, where it often extends close up to the articular surface. The tumour occurs chiefly in young adults, and its general characteristics are like those of giant-cell tumour of bone at other sites (p. 109).

Treatment. The high risk of recurrence after simple curettage and bone grafting has to be balanced against the likely disability after radical excision of the whole of the upper end of the humerus. Each case must be considered on its merits, but if the tumour is large there is much to be said for radical local excision of the affected part of the bone and replacement by a custom-made metal prosthesis.

Buy Membership for Orthopaedics Category to continue reading. Learn more here

Related posts:

Other investigation techniques General affections of the skeleton Soft tissue tumours and other diseases Neck and cervical spine The forearm, wrist, and hand The thigh and knee

Adamss Outline of Orthopaedics