Movements at the wrist

Like the elbow, the wrist comprises two distinct components:

The movements at each component must be examined independently.

The radio-carpal joint. The normal range of flexion (palmar flexion) is 80 ° and of extension (dorsiflexion) 90 °. The range of adduction, or ulnar deviation, is about 35 °, and of abduction, or radial deviation, about 25 °. It is impracticable to measure the movements of the intercarpal joints individually, and it is simplest to regard them as integral parts of the radio-carpal joint.

A rapid and reasonably accurate method of comparing the range of flexion– extension movement on the two sides is as follows: To judge the range of extension: The patient places the palms and fingers of the two hands in contact in the vertical plane and lifts the elbows as far as he can while keeping the ‘heels’ of the hands together (Fig. 16.1). The angle between hand and forearm is easily compared on the two sides. To judge the range of flexion the manoeuvre is reversed. The patient places the backs of the hands together, with the fingers directed vertically downwards, and lowers the elbows as far as he can (Fig. 16.1). The angle between hand and forearm is compared on the two sides.

Fig. 16.1 A A simple method of comparing the range of extension and flexion at the two wrists. B Note the obvious impairment at the left wrist.

The inferior radio-ulnar joint. The normal range is 90 ° of supination and 90 ° of pronation. To determine the range accurately the patient’s elbows must be flexed to a right angle in order to eliminate rotation at the shoulder (see Fig. 15.1).

It must be emphasised that impaired rotation does not necessarily denote an abnormality of the wrist: it may equally well be caused by a disorder of the elbow or of the forearm.

Movements of the hand

Movements of the hand occur mainly at three groups of joints:

Carpo-metacarpal joint of thumb. This joint allows movement in five directions: flexion, or movement of the thumb metacarpal medially in the plane of the palm; extension, or movement of the thumb metacarpal laterally in the plane of the palm; adduction, or movement of the metacarpal towards the palm in a plane at right angles to it; abduction, or movement of the metacarpal away from the palm in a plane at right angles to it; and opposition, or rotation of the metacarpal to bring the thumb nail into a plane parallel with the palm (Fig. 16.2).

Fig. 16.2 To show the difference between flexion of the thumb across the palm A and true opposition B. In opposition the thumb metacarpal is rotated so that the thumb nail lies in a plane parallel with the palm.

Metacarpo-phalangeal joints of thumb and fingers. These joints allow flexion–extension movement through 90 ° (the range is variable and often through as little as 30 ° in the thumb), and a small range of abduction from, and adduction to, the midline of the middle finger.

Interphalangeal joints of thumb and fingers. These are true hinge joints, allowing only flexion and extension. In the fingers, the range of flexion is 90 ° at the proximal interphalangeal joints, and 45 ° at the distal interphalangeal joints. In the thumb, the range of movement at the interphalangeal joint is usually about 80 °.

Power

Test the power of each movement in turn. In the hand this examination demands considerable patience, for each muscle group must be tested individually. Thus in the thumb it is necessary to test the abductors, the adductor, the extensors (longus and brevis), the flexors (longus and brevis), and the opponens. In the fingers test the flexors (profundus and superficialis), the extensor digitorum and extensor indicis, the interossei and the lumbricals. Grip: Test the power of grip, which demands the combined action of the flexors and extensors of the wrist and the flexors of the fingers and thumb.

Nerve function

The state of the median, ulnar, and radial nerves is determined by tests of sensory function, motor function, and sweating. The ulnar nerve normally supplies sensation to the ulnar side of the hand together with the little finger and half the ring finger (Fig. 16.3).

Fig. 16.3 A and B Sensory distribution of the ulnar, radial and median nerves in the hand.

The remainder is largely innervated from the median nerve with some overlap on the dorsum of the hand from the radial nerve (Fig. 16.3). Only a small skin area at the base of the thumb is purely supplied by the radial nerve. Intact function of the median nerve is indicated by ability to oppose the thumb to the little finger (see Fig. 16.2). Intact ulnar nerve function is shown by ability to spread the fingers apart and to bring them together again to grip a card between the middle and ring fingers (Fig. 16.4). An index of radial nerve function is the ability to extend the thumb and to extend the fingers at the metacarpo-phalangeal joints.

Fig. 16.4 B Test of ulnar nerve motor function in interossei. B Test of radial nerve motor function in wrist and finger extensors.

Circulation

The state of the circulation is assessed from the condition of the arterial pulses, the warmth and colour of the digits, the capillary return at the nail beds, and cutaneous sensibility. It should be remembered that sensibility to touch in the fingers is a most useful index of the adequacy of the circulation. Nerves require a blood supply to enable them to conduct impulses, and if the circulation is interrupted sensibility is quickly lost.

Extrinsic sources of forearm and hand symptoms

It is sometimes difficult to determine whether symptoms and signs in the forearm or hand are caused by a local disorder or whether they are referred from a more proximal lesion. This difficulty arises mainly in neurological conditions. For instance, the symptoms of compression of the median nerve in the carpal tunnel may be mimicked closely by a prolapsed cervical disc, and the symptoms of constriction of the ulnar nerve at the elbow may likewise be confused with those from a low cervical disc lesion or a cervical rib. When symptoms in the hand are not satisfactorily explained by the local condition a search must be made for a possible cause in the neck, upper arm, or elbow.

Imaging

Radiographic examination. Routine radiographs should include antero- posterior and lateral projections of the forearm, wrist, and hand. For detailed study of the carpal bones additional oblique projections are required.

If it is suspected that the symptoms may be referred from the neck or proximal part of the limb, radiographs of the appropriate part should be obtained.

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

Acute osteomyelitis is rather uncommon in the forearm bones. As in other sites, the infection may be blood-borne (haematogenous) or it may be introduced from without, usually in consequence of a compound fracture. The haematogenous type occurs mainly in children. It affects the radius more often than the ulna, and the lower metaphysis rather than the upper (see Fig. 7.3B).

The clinical features and treatment are like those of acute osteomyelitis elsewhere.

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

As in other bones, chronic osteomyelitis of the radius or ulna follows an acute infection.

Treatment. In most cases treatment should follow the usual lines, reliance being placed on rest and antibacterial drugs for non-suppurative flares of infection, and on thorough drainage operations and sequestrectomy for persistent purulent discharge.

BONE TUMOURS IN THE FOREARM AND HAND

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

Any type of benign tumour may occur in the bones of the forearm and hand. Only chondroma and giant-cell tumour require further mention here because of their more common occurrence at these anatomical sites.

Chondroma

Enchondroma, which grows within the bone and expands it, is prone to occur in the metacarpals and phalanges of the hand presenting with deformity or pathological fracture. The tumour may be solitary, but in the condition of multiple enchondromatosis, or Ollier’s disease, the tumours may affect many bones in the hand causing ugly swelling and deformity of the fingers (Fig. 16.5). Malignant transformation is hardly known in a solitary chondroma of a bone of the hand, but it is a possibility in cases of multiple enchondromatosis, leading to chondrosarcoma.

Fig. 16.5 Multiple enchondromata in the metacarpals and phalanges.

Treatment. If small, the tumour should be treated expectantly and fractures normally heal with simple splintage. Operation is required only if the tumour is found to be enlarging. Large tumours should be excised and sent for routine histological examination, the bone substance being restored by cancellous bone grafts.

Enchondromas of long bones are less common in the forearm, though these bones may be affected by multiple osteochondroma in the hereditary condition of diaphyseal aclasis (p. 63). These tumours may interfere with the normal growth of the affected bone resulting in shortening and deformity.

Enchondromas occur chiefly in multiple form, in the condition known as dyschondroplasia, Ollier’s disease, or multiple chondromatosis. Their special significance in the forearm lies in the fact that the tumours may interfere with the normal growth of the affected bone. If growth is retarded in one bone but proceeds normally in its partner marked curvature of the bones is to be expected, and it may cause ugly deformity, as seen commonly in dyschondroplasia.

Treatment. Severe deformity from uneven growth of the radius and ulna should be corrected by osteotomy, combined when necessary with excision of the distal ulna, or sometimes the head of the radius.

Giant-cell tumour (osteoclastoma)

The lower end of the radius is one of the common sites in the upper limb for the development of a giant-cell tumour, which though classed as benign may show invasive tendencies. The lower end of the ulna is also susceptible. The tumour extends into the former epiphysial region close up to the articular surface (Fig. 16.6).

Fig. 16.6 A and B Radiographs of wrist showing a giant cell tumour in the distal radius. The lucent lesion has ill-defined proximal margins with a narrow zone of transition and lies in a typical subarticular position in the epiphysis.

Treatment. If the tumour is in the lower end of the radius radical excision and replacement by a suitable bone graft is to be recommended. A graft obtained from the upper part of the fibula is suitable because its shape matches that of the original bone. Ideally, the graft should be taken with the supplying artery and veins, which are anastomosed to suitable vessels in the recipient area by a microsurgical technique. If the lower end of the ulna is the part affected the bone should be excised up to a point well proximal to the tumour. The resulting disability is negligible.

VOLKMANN’S ISCHAEMIC CONTRACTURE¹

This is a flexion deformity of the wrist and fingers from fixed contracture of the flexor muscles in the forearm.

Cause. It is caused by ischaemia of the flexor muscles, brought about by injury to, or obstruction of, the brachial artery near the elbow; or by tense oedema of the soft tissues of the forearm constrained within an unyielding fascial compartment.

Pathology. The effects of sudden occlusion of the brachial artery vary. In a few worst cases gangrene of the fingers will follow. Usually, however, the collateral circulation is sufficient to keep the hand alive, but not to nourish adequately the flexor muscles of the forearm or the main peripheral nerve trunks. The ischaemia that follows tense oedema in the anterior fascial compartment of the forearm, a consequence of severe injury in the region, has similar effects. Necrosis of muscle fibres of the forearm flexor group – especially the flexor digitorum profundus and flexor pollicis longus – with subsequent fibrosis and shortening, is the essential feature of Volkmann’s contracture. It is often associated with temporary or permanent ischaemic paralysis of the peripheral nerves, especially the median nerve.

Any major fracture in the elbow region or upper forearm may lead to arterial occlusion. That most commonly responsible is a supracondylar fracture of the humerus with displacement, the brachial artery being severed or contused by the sharp lower end of the main shaft fragment (Fig. 16.7). Contusion alone is sufficient to interrupt the flow of blood, because the artery goes into spasm and its lumen may be occluded by thrombosis.

Fig. 16.7 To show how a supracondylar fracture of the humerus may damage the brachial artery, with risk of gangrene or ischaemic contracture. Over-tight plaster or dressings may have the same result.

Progressive oedema within the closed anterior fascial compartment of the forearm – for instance after fracture of the forearm bones – is commonly responsible for obstruction of the arterial flow (compartment syndrome).

In some cases the cause of the vascular obstruction is an over-tight plaster or bandage.

Clinical features. The condition is commonest in children. After sustaining a supracondylar fracture of the humerus or some other injury in the elbow region or forearm, the child complains of severe pain in the forearm.

On examination in the incipient stage, the fingers are white or blue, and cold. The radial pulse is absent. Active finger movements are weak and painful. Passive extension of the fingers is especially painful and restricted. There may or may not be evidence of interruption of nerve conductivity – namely, anaesthesia of the fingers and paralysis of the small muscles of the hand.

In the established condition, which develops gradually within a few weeks of the injury, there is a striking flexion contracture of the wrist and fingers, from shortening of the fibrotic forearm flexor muscles (Fig. 16.8). Sensory and motor paralysis of the hand may persist as complicating factors, but they do not form an essential feature of Volkmann’s contracture as such.

Fig. 16.8 Typical appearance of the hand in established Volkmann’s ischaemic contracture.

Diagnosis. In the incipient stage absence of the radial pulse, with marked unwillingness to extend the fingers because of pain, should always arouse suspicion of Volkmann’s contracture. If there are also anaesthesia and paralysis of the hand the diagnosis is practically certain. In the established condition the history and clinical features make the diagnosis clear.

Volkmann’s ischaemic contracture bears no real resemblance to Dupuytren’s contracture (p. 321), for it affects the wrist as well as all the joints of the fingers, and there is no palpable thickening in the palm. Moreover the contracture is demonstrably brought about by shortening of the flexor muscles, because if the wrist is flexed passively to relax the flexor tendons the range of extension at the finger joints is increased. Conversely, if the tendons are relaxed by flexing the fingers fully the range of wrist extension is increased (Fig. 16.9).

Fig. 16.9 In Volkmann’s contracture the wrist can be partly extended if the fingers are flexed A, and the fingers can be partly extended if the wrist is flexed B : but the shortened fibrotic flexor muscles prevent extension of wrist and fingers together.

Treatment. In the incipient stage the problem is that of dealing with a sudden occlusion of the brachial artery or obstruction to the blood flow within a tightly congested fascial compartment. The case must be handled as an emergency, because the effects of occlusion become irreversible after about six hours. The following action must be taken:

First step. All splints, plaster, and bandages that might be obstructing the circulation are removed. In the case of a fracture, gross displacement of the fragments is corrected as far as possible by gentle manipulation and a well-padded plaster splint is applied. Likewise if the elbow is dislocated it must be reduced without delay. Heat cradles or hot bottles are applied over the other three limbs and trunk to promote general vasodilation.

If these measures fail to bring about a return of adequate circulation within half an hour, the next step is taken:

Second step. At operation the anterior fascia of the forearm is exposed and split longitudinally throughout its length to open the fascial compartment, allowing the muscles to bulge through the gap. The brachial artery is then explored. If there is occlusion from kinking or spasm of the artery an attempt is made to relieve it by freeing the vessel and applying papaverine. If this fails, the artery may be distended by the injection of saline between clamps. In the last resort, the artery may have to be opened and damaged intima removed; or the damaged length of artery may be excised and continuity restored by a vein graft. These procedures are best accomplished using magnification techniques, by a surgeon with wide experience of vascular surgery.

In the established stage restoration to normal is impossible: reconstructive surgery at best can only improve what function remains. The choice of treatment depends upon the circumstances of each case. In a mild case acceptable function may be restored by intensive exercises guided by a physiotherapist: such cases are however exceptional. In more severe cases the muscle shortening may be counteracted by shortening of the forearm bones, or by detachment and distal displacement of the flexor muscle origin (muscle slide operation).

In selected cases with severe muscle infarction, however, the best results are probably obtained by excision of the dead muscles and subsequent transfer of a healthy muscle (for example, a wrist flexor or a wrist extensor) to the tendons of flexor digitorum profundus and of flexor pollicis longus to restore active flexion of the digits. These muscle transfers may be combined, in appropriate cases, with arthrodesis of the wrist. When the median nerve is irreparably damaged by ischaemia nerve grafting is sometimes successful in restoring limited nerve function.

MADELUNG’S DEFORMITY¹ (Radio-ulnar dyschondrosteosis)

Madelung’s deformity (radio-ulnar dyschondrosteosis) is a congenital subluxation or dislocation of the lower end of the ulna, from malformation of the bones. Although it is seemingly a localised disorder there may be minor generalised abnormalities of bone structure, often with short stature.

A similar wrist deformity is more often caused by disease or injury, such as a fracture of the lower end of the radius with proximal displacement of the lower fragment.

The deformity varies in degree from a slight prominence of the lower end of the ulna at the back of the wrist, to complete dislocation of the inferior radio-ulnar joint with marked radial deviation of the hand (Fig. 16.10). The more severe types of deformity may be associated with congenital absence or hypoplasia of the radius.

Fig. 16.10 Relative shortening of radius with subluxation of inferior radio-ulnar joint, radial deviation of the hand and prominent head of ulna (Madelung’s deformity).

Treatment. If the disability justifies operation the lower end of the ulna should be excised. In a severe case, with marked radial deviation of the hand, it may be necessary also to fuse the radius (or ulna, if the radius is absent) to the carpus in order to gain satisfactory correction.

PYOGENIC ARTHRITIS OF THE WRIST AND HAND (General description of pyogenic arthritis, p. 96)

Pyogenic arthritis of the wrist is uncommon. Infection may be haematogenous, or it may be introduced through a penetrating wound. Spread from a focus of osteomyelitis is rare, partly because osteomyelitis itself is uncommon in the forearm bones, and partly because the lower metaphysis of the radius is entirely outside the capsule of the joint. (The lower metaphysis of the ulna is partly intracapsular (see Fig. 7.2).)

In the hand, any of the small joints may be infected by pyogenic organisms. The distal interphalangeal joints of the digits are prone to infection spreading from a suppurative lesion in the adjacent pulp space, or from a penetrating wound. These infections often cause permanent damage to the joint, with impairment of movement or even rigid ankylosis. Radiographs in the late stage of infection may show diffuse rarefaction, loss of cartilage space and some bone destruction.

The clinical features and treatment of pyogenic arthritis are similar to those at other sites.

RHEUMATOID ARTHRITIS OF THE WRIST AND HAND (General description of rheumatoid arthritis, p. 134)

Rheumatoid arthritis commonly affects the wrists and hands and is a major cause of serious loss of function and of ugly deformity. Usually many or all of the joints of the hand are affected, though occasionally the disease may begin in a single joint. Affected joints are swollen from synovial thickening, and movement is restricted. In the later stages articular cartilage and the underlying bone are eroded, and the fingers tend to deviate medially (‘ulnar drift’), with dorsal prominence of the metacarpal heads and characteristic visible deformity (Fig. 16.11A). At the wrist joint the disease commonly results in dorsal subluxation and dislocation of the ulnar head accompanied by subluxation of the carpus on the radius and radial deviation of the hand. Radiographs do not show any abnormality at first. Later, there is diffuse rarefaction of the bones. Later still, in progressive disease, destruction of cartilage leads to narrowing of the joint space (Fig. 16.11B), and the subchondral bone may be eroded.

Fig. 16.11 A Typical appearance of hand in long-established rheumatoid arthritis of wrist, metacarpo-phalangeal and interphalangeal joints. B Radiograph of the hand showing advanced erosive arthropathy due to rheumatoid arthritis. There is extensive destruction and subluxation of the radio-carpal, carpal, metacarpo-phalangeal, and interphalangeal joints with typical ulnar deviation of the fingers.

Important though these joint changes are in rheumatoid disease of the hand, equally serious disability may be caused by involvement of the soft tissues. These soft-tissue changes may take several forms, the most important of which are:

Chronic tenosynovitis. Masses of greatly thickened vascular synovial tissue envelop the flexor or the extensor tendons over the wrist or in the hand. Proliferation of the tenosynovium combined with nodular formation in the flexor tendon may produce symptoms of trigger finger.

Rupture of tendons. Both the extensor and the flexor tendons are liable to spontaneous rupture, from softening or fraying where they lie within inflamed synovial sheaths. The extensor pollicis longus, extensor digitorum, and extensor digiti minimi are the tendons that most commonly rupture.

Contracture of intrinsic muscles. Fixed contracture of the intrinsic muscles of the hand may follow fibrosis induced by the disease. It leads to inability to flex the interphalangeal joints fully when the metacarpo-phalangeal joint is held extended.

Compression of the median nerve. A secondary effect of the synovial proliferation within the carpal tunnel is that the median nerve may be compressed by the transverse carpal ligament.

Treatment

Management of these complex disabilities of the hand is difficult and often unsatisfactory. The tendency of the disease to progress during months or years of activity means often that the hand becomes seriously crippled. Nevertheless much can be done with modern medical therapy to retard the progress of the disease and to prevent or correct deformity, either by conservative treatment alone or by conservative treatment combined with operation.

Conservative treatment. The general plan of treatment is like that for rheumatoid arthritis as a whole (p. 137). It will usually include the administration of non-steroidal anti-inflammatory drugs, or in more resistant disease second-line drug therapy may be required with gold, penicillamine, or immuno-suppressive agents. Cortisone and related steroids should be avoided if possible because of their undesirable side effects. Physiotherapy is of value: it should take the form of warm water or wax baths, with mobilising exercises and encouragement in active use of the hand. During an acute exacerbation the wrist joint may be immobilised temporarily in a moulded polythene splint or plaster of Paris back slab, but immobilisation is never advised for the joints of the fingers other than with a dynamic active splint.

Operative treatment. In carefully selected patients operation can be a valuable adjunct to conservative treatment, though it can never replace it. It should never be undertaken lightly, but only after careful deliberation and full discussion with the patient as well as the other members of the treatment team. Operations, particularly soft-tissue procedures, are often more rewarding when carried out in the fairly early stages of the disease, before deformity from changes in the joints and soft tissues has become fixed and irreversible. Depending upon the nature of each individual case, operation may take one or more of the following forms.

Synovectomy. Excision of masses of thickened synovial tissue from tendon sheaths or from joints may slow down the destructive progress of the disease, and prevent tendon rupture and joint dislocation.

Arthroplasty. When the metacarpo-phalangeal or interphalangeal joints are badly disorganised arthroplasty by the insertion of a flexible silicone-rubber (‘Silastic’) prosthesis may sometimes be appropriate (Fig. 16.12). But the patient must be prepared to cooperate in a long programme of rehabilitation afterwards. The improvement gained is often cosmetic rather than functional. The benefit is not always lasting and deformity may recur because of breakage or loosening of the prosthesis.

Fig. 16.12 Flexible silicone-rubber prosthesis used for arthroplasty of metacarpo-phalangeal joint.

Arthrodesis. For selected joints that are painful, stiff, deformed, or unstable, arthrodesis in the position of most useful function is sometimes the best solution to the problem. When the wrist joint is badly destroyed, arthrodesis of the wrist in a neutral or slightly palmar flexed position, will provide a stable basis for other reconstructive procedures in the hand. The metacarpo-phalangeal joint of the thumb may require fusion to restore deformity and to provide the stability required for a pinch grip.

Tendon repair or replacement. Ruptured tendons may be repaired by suture or by grafting when practicable, or their lost function may be compensated by a tendon transfer operation (p. 44).

Release of tight intrinsic muscles. Impaired finger movement and grasp from fixed contracture of the intrinsic muscles can be improved by partial division of the aponeurotic insertion of the muscles into the extensor expansion at the back of each finger.

Carpal tunnel decompression. Division of the transverse carpal ligament and excision of the proliferative synovium will provide adequate decompression for the median nerve when neuropathy is present.

OSTEOARTHRITIS OF THE WRIST (General description of osteoarthritis, p. 140)

Although uncommon compared with osteoarthritis of the hip or knee, osteoarthritis of the wrist is a well-recognised sequel to certain injuries and diseases affecting the joint.

Cause. Although it is essentially a wear-and-tear process osteoarthritis seldom develops in a wrist that was previously normal. The wear and tear is nearly always accelerated by previous injury to, or disease of, the joint surfaces. The commonest predisposing factors are comminuted fracture of the lower end of the radius with involvement of the articular surface, fracture of the scaphoid bone complicated by failure of union or avascular necrosis (osteonecrosis) of the distal fragment, dislocation of the lunate bone, Kienböck’s disease of the lunate bone, and long-established (‘burnt out’) rheumatoid arthritis.

Pathology. The predominant change is degeneration and wearing away of the articular cartilage lining the joint surfaces. The changes eventually involve all the carpal joints as well as the radio-carpal joint.

Clinical features. Months or years after one of the predisposing conditions mentioned, the patient notices gradually increasing pain and stiffness of the wrist, worse on activity. On examination the wrist is slightly thickened from bony irregularity, but the swelling is not marked. The skin temperature is normal. Movements are markedly restricted, and painful if forced at the extremes.

Radiographic features. Radiographs show narrowing of the cartilage space and sharpening or spurring of the bone at the joint margins. The underlying causative condition (for example, an ununited fracture of the scaphoid bone) is usually evident (Fig. 16.13).

Fig. 16.13 Osteoarthritis of the wrist caused by an ununited fracture of the scaphoid bone. Note the diminished cartilage space, sclerosis, and spurring of bone at the joint margins, mainly at the radial side of the wrist.

Treatment. In mild cases the condition is best left alone, especially if the patient can avoid subjecting the wrist to heavy stress. When active treatment seems necessary, a choice must be made between conservative and operative methods. Conservative treatment can only diminish the symptoms; it can never remove them. Nevertheless it is usually worth a trial. The most useful method is to provide support for the wrist by a detachable splint made from moulded plastic (Fig. 16.14).

Fig. 16.14 Polythene wrist support. A splint such as this is sometimes used in the conservative treatment of osteoarthritis of the wrist.

Operative treatment sometimes becomes necessary when the disability is severe. The only reliable method is by total arthrodesis of the wrist, with ablation of the radio-carpal and all the intercarpal joints. The inferior radio-ulnar joint and the triangular fibrocartilage are left undisturbed; so rotation of the forearm is preserved.

OSTEOARTHRITIS OF THE JOINTS OF THE HAND

The metacarpo-phalangeal joints and the interphalangeal joints of the hand are frequently the site of osteoarthritis in the elderly. Such manifestations are relatively unimportant and in most cases treatment is not required. Commonly involved are the carpo-metacarpal joint of the thumb (trapezio-metacarpal joint) (Fig. 16.15A) and the distal interphalangeal joints (Fig. 16.15B).

Fig. 16.15 A Osteoarthritis of the trapezio-metacarpal joint. Note the marked narrowing of the cartilage space and the large osteophytes. B Typical Heberden’s nodes, a characteristic feature of degenerative arthritis of the interphalangeal joints.

KIENBÖCK’S DISEASE¹ (Osteochondritis of the lunate bone)

Kienböck’s disease is an uncommon affection of the lunate bone characterised by temporary softening, fragmentation, and liability to deformation. It tends to predispose to the later development of osteoarthritis of the wrist.

Cause. The precise cause is unknown. A disturbance of blood supply, possibly from thrombosis of a nutrient vessel, is believed to be the essential factor, but how it comes about is not clear. Repeated injury (for example, using the front of the wrist to drive a chisel in carpentry, or operating a pneumatic road drill) has sometimes been noted in the case history, but a causative connection is not fully established.

Pathology. In its behaviour the disease resembles osteochondritis of developing epiphysial centres in children (p. 130), such as Perthes’ disease: in effect, it is a form of avascular necrosis (osteonecrosis). The bone becomes granular in texture, small dense fragments being interspersed with softened areas. In this state the bone eventually crumbles, and under the pressure imposed by muscle action and use of the wrist it gradually becomes compressed into a thin saucer-shaped mass. The overlying cartilage dies. After about two years the bone texture is restored to normal, but the bone remains deformed and lacks a smooth cartilaginous covering. The bone behaves like a piece of grit in a bearing and leads gradually to the development of osteoarthritis of the wrist.

Clinical features. There is pain in the wrist, most marked at the centre of the joint over the lunate area. The pain is worse during active use of the wrist. Because of the pain, the strength of grip is impaired.

On examination there is discomfort on pressure over the lunate bone. An important sign is that movements of the wrist are substantially restricted and cause pain if forced.

Radiographs are diagnostic. In the early stages the lunate bone appears slightly more dense than the surrounding bones, and if its depth is compared with that of the lunate bone of the sound wrist it is seen to be reduced, though only slightly at first (Fig. 16.16). Later, the bone has a fragmented appearance, small areas of increased density being scattered through it, and the flattening of the bone becomes obvious. Later still, signs of osteoarthritis of the wrist are evident.

Fig. 16.16 Kienböck’s disease of the lunate bone. Note the increased density, fragmentation and beginning compression of the bone.

Treatment. Treatment is often rather unsatisfactory. It must depend upon the duration of the symptoms and the degree of damage to the wrist. In the earliest stage, when radiographic changes are only just perceptible, there is probably a place for protecting the wrist in plaster for two or three months in the hope that the condition will resolve through revascularisation of the bone. But once the disease is clearly established surgical treatment is recommended. If the wrist is free from arthritis it is probably best to excise the lunate bone and replace it with a metal prosthesis. This probably gives better results than excision alone, without replacement, but the long-term results are nevertheless uncertain.

In late cases, if severe osteoarthritis is already present, excision of the lunate bone is of no avail. Treatment should then be the same as for osteoarthritis of the wrist (p. 307).

ACUTE INFECTIONS OF THE FASCIAL SPACES OF THE HAND

Acute infections of the hand account for a considerable proportion of the work of a casualty department or emergency room and are of great importance in industrial medicine. Unless they are treated efficiently they can lead to prolonged or even permanent disability, with impairment of working capacity.

SPECIAL FEATURES OF INDIVIDUAL LESIONS

Nail-fold infection (paronychia)

This is one of the commonest but least serious types of hand infection. The subcuticular plane beneath the nail fold is potentially continuous, at the base and sides of the nail, with the subungual space deep to the nail. Infection beginning in the nail fold may therefore easily spread under the nail (Fig. 16.17), and the resulting abscess cannot be drained effectively unless part of the nail is removed.

Fig. 16.17 Diagrammatic section showing the site of suppuration in nail-fold infection (paronychia) and in pulp-space infection (whitlow). In nail-fold infection the pus is beneath the cuticle and may extend under the nail, as shown. In pulp-space infection the pus lies in the tough fibro-fatty tissue immediately in front of the distal phalanx.

Clinical features. There are pain, redness, and swelling at one or both sides of the nail fold and at the base of the nail. There is local tenderness over the reddened area. If suppuration has extended deep to the nail there is marked tenderness on pressure upon the nail.

Complications: These are:

1 extension to the pulp space

2 chronic paronychia, following inadequate treatment of the acute infection.

Treatment. In this type of infection conservative measures are often successful if begun within a few hours of the onset. When local suppuration has occurred the subcuticular abscess is drained by raising the cuticle from the nail or by raising it as a short flap after incising it vertically at one or both corners (Fig. 16.18A). If pus has extended under the nail the proximal third of the nail must also be removed.

Fig. 16.18 A Technique of drainage of paronychial abscess. For the mildest infections it is sufficient to raise the cuticle alone without incising it; but better drainage is secured by a vertical incision through the cuticle, on one or both sides. When pus has extended beneath the nail it is necessary also to remove the proximal third of the nail (shaded area). B Incision for drainage of pulp abscess. The incision is deepened across the pulp, in front of the phalanx, and the abscess cavity is cleared out under direct vision.

Subcutaneous infections (other than pulp-space infections)

These infections are common. Infection may occur in the subcutaneous plane at any point in the hand. Common sites are the middle or proximal segment of a finger, and the web spaces between the digits. Less common sites are the palm of the hand and the dorsum of the hand. These superficial spaces are clearly demarcated from the deep palmar spaces next to be described, and must not be confused with them.

Clinical features. The infection may arise in any part of the hand or fingers. There is localised swelling with redness and tenderness. In many cases the infection has spread through the skin from a subcuticular infection or blister.

Complications are:

1 sloughing of skin over the lesion

2 spread to the deep space or to the flexor tendon sheaths.

Treatment. Surgical drainage is by a short incision appropriately placed to reach the abscess without harming important structures or leaving an awkward scar. In the case of a web-space infection the incision should not divide the skin fold of the web: a short transverse incision in the palm just proximal to the skin fold is adequate (see Fig. 16.20B).

Fig. 16.20 A Surface marking of the deep palmar spaces. The thenar space is continuous with the first lumbrical canal and the mid-palmar space with the second, third, and fourth lumbrical canals. B Incisions for drainage through the web spaces.

Thenar space infection

This is a well-defined entity but it is very uncommon. It may arise by extension from a subcutaneous lesion or a tendon sheath infection. The thenar space lies deeply under the lateral (radial) half of the hollow of the palm. It is the interval between the adductor pollicis muscle behind and the flexor tendon of the index finger and the first and second lumbrical muscles in front. Medially it is separated from the mid-palmar space by a fibrous septum that extends deeply from the fascia on the deep surface of the flexor tendons to the fascia covering the interossei and adductor pollicis muscle (Figs 16.19 and 16.20A). The space is prolonged forwards into the delicate sheath that surrounds the first lumbrical muscle. It sometimes communicates also with the second lumbrical canal. The lumbrical canals thus provide a potential communication between the subcutaneous web spaces and the thenar space: in practice, however, it is rare for infection to spread along this route.

Fig. 16.19 The deep palmar spaces – the thenar space and the mid-palmar space – shown in diagrammatic transverse section.

Clinical features. The radial half of the palm is ballooned out and the swelling extends to the dorsal aspect of the web between thumb and index finger. Treatment: Drainage is by an incision at the dorsal aspect of the first web space (Fig. 16.20B).

Tendon sheath infection

This is rare, but important because prompt treatment is essential if the function of the finger is to be preserved. Distinction must be made between the tough fibrous sheaths, which exist only in the digits, and the flimsy synovial sheaths, which line the fibrous sheaths and, in the case of the thumb and little finger, extend proximally into the palm. In acute infections of the tendon sheaths (acute infective tenosynovitis) the pus is within the synovial sheath and it is confined only by the limits of the sheath. The flexor sheaths of the index, middle, and ring fingers end proximally at the level of the transverse palmar skin crease (Fig. 16.21A). The sheaths of the thumb and little finger extend proximally through the palm to end two or three centimetres above the level of the wrist. The proximal part of the sheath for the thumb is known as the radial bursa. The sheath for the little finger opens out proximally into the ulnar bursa, which encloses the grouped tendons of flexor digitorum superficialis and flexor digitorum profundus (Fig. 16.21A).

Fig. 16.21 A The synovial flexor sheaths. Whereas the sheaths for the index, middle, and ring fingers end proximally at the bases of the fingers those for the thumb and little finger extend upwards to become continuous with the radial bursa and the ulnar bursa respectively. B Incisions for drainage and irrigation of tendon sheaths and bursae.

Clinical features. The finger is swollen throughout its length, and acutely tender over the flexor tendon sheath. It is held semiflexed and the patient is unwilling to extend it because of pain.Complications: These are:

1 necrosis of the tendons and adhesions between tendon and sheath, causing permanent stiffness of the finger in semi-flexion

2 spread of infection to involve the radial bursa (from the flexor sheath of the thumb), or the ulnar bursa (from the sheath of the little finger).

Treatment. Systemic antibiotic therapy is begun immediately. The sheath is opened at its proximal end in the palm and at its distal end (Fig. 16.21B), and irrigated with antibiotic solution through a fine tube passed along the sheath; the tube is withdrawn and the wounds are packed lightly open.

If the radial bursa or the ulnar bursa is infected it must be drained and irrigated through an additional incision in the palm (Fig. 16.21B).

CHRONIC INFECTIVE TENOSYNOVITIS (Including compound palmar ganglion)

Chronic inflammation of tendon sheaths in the lower forearm and hand may occur in response to low-grade infection, usually tuberculous. It is entirely distinct from acute tenosynovitis and is not preceded by it. It is now seen only rarely in Western countries except in some patients with chronic rheumatoid arthritis.

Pathology. The flexor tendon sheaths in the lower forearm and hand are those most commonly affected. The affected sheaths are greatly thickened and show the changes of chronic inflammation. There may be histological evidence of tuberculosis in the thickened tissue. The sheaths often contain an excess of fluid and there may be collections of small fibrinous bodies. The tendons themselves are affected only slightly.

Clinical features. There is a gradual onset of swelling, with mild aching pain, in the region of the affected tendon sheaths – usually the flexor sheaths of the lower forearm and hand. The function of the fingers and thumb is impaired with moderate restriction of flexion and extension of the digits. The swelling is confined to the line of the tendon sheaths in the front of the forearm and the proximal part of the palm (Fig. 16.22). In many cases fluctuation can be elicited between the forearm swelling and the swelling in the palm. This physical sign led to the use of the term compound palmar ganglion, though this is a misnomer as the common ganglia around the wrist joint arise from the synovial cavity of the joint and not the tendon sheath.

Fig. 16.22 Compound palmar ganglion. The swellings in the palm and at the front of the wrist are continuous deep to the flexor retinaculum, and fluctuation can be elicited between them.

If an active tuberculous lesion is found elsewhere in the body it is reasonable to infer that the tenosynovitis is also tuberculous.

Treatment. In mild cases in which the function of the fingers and thumb is not impaired conservative treatment is advised. In tuberculous cases a course of the appropriate antibacterial drugs is given (see p. 102).

In severe cases operation is recommended. It consists in excising thoroughly all the thickened and oedematous synovial membrane. After operation finger movements are encouraged and practised daily under the supervision of a physiotherapist. A useful range of finger movement is usually restored, but permanent inability to flex the fingers fully into the palm may have to be accepted.

SOFT-TISSUE TUMOURS IN THE HAND (General description of soft-tissue tumours, p. 157)

Soft-tissue tumours are uncommon in the hand but special mention must be made of an unusual tumour that is the second most common cause of swelling in the hand after simple ganglion cyst. This is the giant-cell tumour of tendon sheath (localised nodular tenosynovitis).

GANGLION (Simple ganglion)

A ganglion is the commonest cystic swelling at the back of the wrist.

Pathology. Conflicting views have been put forward on the origin of ganglia. Some believe that they represent a degenerative process. Others claim that they are benign tumours of tendon sheath or joint capsule. The cyst wall is of fibrous tissue and there is no true endothelial lining. It is connected at some point with a joint capsule or tendon sheath, but there is no communication between the joint cavity or tendon sheath and the interior of the cyst. The cyst is usually unilocular. The contained fluid is clear and viscous.

Clinical features. Ganglia are commonest at the back of the wrist, where they are often seen in adults of any age (Fig. 16.23). They also occur, less commonly, at the front of the wrist, or in the palm or fingers. Ordinarily there are no symptoms other than the swelling itself and, sometimes, discomfort or slight pain. On examination the swelling may be soft and obviously cystic, but more often it is tense. It is often mistaken for a bony prominence – but careful tests will show that it is fluctuant.

Fig. 16.23 A simple ganglion at the back of the wrist. This is the commonest site.

Complications. A ganglion arising deeply in the wrist or palm may interfere mechanically with the ulnar or the median nerve or their branches. There will be motor and usually sensory impairment in the distribution of the particular branch affected.

Treatment. A ganglion is harmless and in the absence of pain or complications it may safely be left alone. Sometimes the ganglion can be dispersed subcutaneously by firm local pressure. This rather dramatic treatment is harmless and temporarily effective, but the ganglion may slowly reappear. An alternative method of providing temporary relief is to aspirate the cyst with a wide-bore needle. Lasting cure can be ensured only by complete excision of the ganglion – not always an easy task because the thin-walled sac often tracks deeply between the tendons, where it may be torn and a fragment left behind, leading to recurrence. In children there is a tendency to spontaneous resolution; so the question of excision may be deferred.

A ganglion that is interfering with a peripheral nerve demands operative excision without delay.

CARPAL TUNNEL SYNDROME (Compression of median nerve in carpal tunnel)

Constriction of the median nerve as it passes beneath the flexor retinaculum is the commonest compression neuropathy in the arm, resulting in discomfort in the hand, especially in middle-aged or elderly women.

Cause. In the majority of cases no primary cause can be discovered, but any space-occupying lesion within the carpal tunnel may be responsible. Recognised causes are chronic inflammatory thickening of the tendon sheaths (as in rheumatoid arthritis), osteoarthritis of the wrist, deformity or malunion after fracture of the lower end of the radius, and myxoedema.

Pathology. The median nerve lies beneath the flexor retinaculum in company with the flexor tendons of the hand. If the available space within this strong-walled tunnel is reduced the nerve is compressed against the flexor retinaculum. When the retinaculum is divided in such a case the nerve may be found constricted and flattened where it lay behind it. The ulnar nerve does not pass behind the flexor retinaculum; so it is not liable to compression in this way.

Clinical features. The condition is commonest in women in or beyond middle life. The symptoms are sensory and motor. There is tingling, numbness, or discomfort usually in the radial three and a half digits (that is, in the normal distribution of the median nerve), and there is a feeling of clumsiness in carrying out fine movements such as those concerned in sewing. Distressing tingling is often prominent during the night and the patient may have to work the fingers or shake the hand to gain relief, making this an almost diagnostic symptom.

On examination the findings vary with the degree and duration of the compression. At first there are no objective clinical findings. Later there may be blunting of sensibility in the median nerve distribution. In a severe case there may eventually be evident wasting and weakness of the median-innervated small muscles of the hand, particularly abductor pollicis brevis. The Durkan test may be positive when direct compression of the median nerve at the carpal tunnel for 30 seconds reproduces numbness and tingling in one or more of the radial digits.

Investigations. Electrophysiological nerve conduction testing may show decreased conduction velocity in the affected part of the median nerve. This is a reliable confirmatory test if the clinical diagnosis is in doubt.

Diagnosis. Care must be taken to exclude other causes of neurological disturbance in the hand, especially those arising in the neck from interference with the brachial plexus, and lesions of the median nerve elsewhere in its course.

Treatment. A trial may be made of conservative treatment by supporting the wrist at night for three weeks with a simple splint in a neutral position. When the symptoms arise in pregnancy, relief that lasts until after delivery (when the symptoms usually subside spontaneously) may be gained by the injection of hydrocortisone alongside the nerve at wrist level. This may be tried also in other cases and may cure the symptoms in 50% of patients. If it is unsuccessful full relief is assured by dividing the flexor retinaculum to decompress the nerve. This is a simple operation that may be done either through an open incision or (with slightly greater risk to the motor branch of the median nerve) by an endoscopic technique.

DUPUYTREN’S¹ CONTRACTURE (Contracture of the palmar aponeurosis; Dupuytren’s disease)

This is an easily recognised condition characterised in the established phase by flexion contracture of one or more of the fingers from thickening and shortening of the palmar aponeurosis.

Cause. This is unknown. There is a hereditary predisposition. In a predisposed person injury possibly plays a part but its exact significance is uncertain. There is an increased incidence of the disorder among epileptics, but this is possibly related to the use of anticonvulsant drugs rather than to an underlying genetic association between the two diseases.

Pathology. The palmar aponeurosis (palmar fascia) is normally a thin but tough membrane whose fibres radiate from the termination of the palmaris longus tendon at the front of the wrist to gain insertion into the proximal and middle phalanges of the fingers. It lies immediately beneath the skin. In Dupuytren’s contracture the aponeurosis, or part of it, becomes greatly thickened (often to half a centimetre or more), and it slowly contracts, drawing the fingers into flexion at the metacarpo-phalangeal and proximal interphalangeal joints. The medial (ulnar) half of the aponeurosis is affected most, and serious flexion deformity is usually confined to the ring and little fingers, with only moderate deformity of the middle finger (Figs 16.24 and 16.25). The joints themselves are unaffected at first, but in long-established cases secondary capsular contractures occur. The flexor tendons in the palm are in no way affected.

Fig. 16.24 Early Dupuytren’s contracture. There is a nodule of thickened aponeurosis in the palm, opposite the base of the ring finger, with slight puckering of the skin; but so far there is no flexion contracture of the fingers.

Fig. 16.25 A typical example of Dupuytren’s contracture of the palmar aponeurosis in which the ring finger has been drawn down into flexion. Note the tight band of thickened aponeurosis immediately under the skin. The band has sometimes been mistaken for a contracted flexor tendon.

The plantar aponeurosis in the foot is occasionally affected, but in the foot the lesion usually takes the form of a firm nodule under the instep rather than of a contracture involving the toes (Fig. 16.26). Other parts that may be affected include the penis. Thus although the hands are primarily affected, the condition is sometimes much more widespread (Dupuytren’s disease).

Fig. 16.26 Typical nodule in the sole of the foot in Dupuytren’s disease.

Clinical features. The affection is much more common in men than in women. Often both hands are affected. The earliest sign is a small thickened nodule in the mid-palm opposite the base of the ring finger (Fig. 16.24). The area of thickening gradually spreads from this point, giving rise eventually to firm cord-like bands that extend into the ring finger or little finger, or both, and prevent full extension of the metacarpo-phalangeal and proximal interphalangeal joints (Fig. 16.25). The skin is closely adherent to the fascial bands, and is often puckered. The flexion deformity becomes progressively worse in the course of months or years.

In some cases these changes in the palm are accompanied by thickening over the dorsum of the interphalangeal joints (knuckle pads). The feet may also show nodules in the sole (Fig. 16.26). Occasionally the penis is distorted by thickened bands.

Diagnosis. The thickened bands of palmar aponeurosis must not be mistaken for contracted flexor tendons. It is easily confirmed that the bands are distinct from tendons because they do not move when the fingers are flexed and extended.

Treatment. The only effective treatment is by operation, though a number of proteolytic drugs administered by injection are under trial. However, operation is not necessary in every case: a contracture that is not progressing rapidly is often better left alone, especially in an elderly patient. Surgery is usually required if the flexion contractures exceed 30 ° at the metacarpo-phalangeal, or 15 ° at the interphalangeal joints. Operation entails excision of the thickened part of the palmar aponeurosis by painstaking dissection to avoid damage to digital nerves. Simple division of the taut contracted bands is less satisfactory because the contracture tends to recur. In selected cases multiple releases of metacarpo-phalangeal contractures through small separate incisions may give permanent improvement in over 50% of patients. In advanced cases the contractures may involve the overlying palmar skin and there may be a need to use skin grafting following radical excision. An alternative is to apply a splint to maintain the correction and allow the skin to heal by secondary intention.

RUPTURE OR SEVERANCE OF TENDONS IN THE HAND

Most tendon divisions in the hand are caused by cuts with sharp objects such as glass or knives. Certain tendons are prone to rupture: thus the extensor tendon of a finger is easily torn from its insertion into the distal phalanx by sudden forced flexion of the finger; and the extensor pollicis longus tendon is liable to rupture spontaneously after fractures of the lower end of the radius in consequence of its becoming frayed where it crosses the roughened bone. In rheumatoid arthritis, also, spontaneous rupture – especially of an extensor tendon – is common.

Clinical features and diagnosis. Loss of function of a tendon is obvious clinically. When the findings are correlated with the history the diagnosis is usually clear.

Treatment. This varies according to the tendon affected and the site of severance or rupture (see below and Fig. 16.27). Sometimes treatment is unnecessary or undesirable, but more often operative reconstruction is to be advised: the tendon is either sutured directly or replaced by a free tendon graft or by a tendon transfer, according to circumstances (see pages 46 and 44 for the principles of these methods).

Fig. 16.27 Treatment of tendon injuries at various sites. A Flexor tendons. B Extensor tendons. For details, see text.

SPECIAL FEATURES OF INDIVIDUAL LESIONS

Injuries of flexor tendons

Division within a fibrous flexor sheath of a finger. Severance at this site presents the most difficult problem of all tendon injuries. The prognosis is uncertain after operative repair or reconstruction because of the proclivity of the tendon to adhere to the sheath.

Treatment. If a flexor superficialis tendon alone is divided and the flexor profundus is intact treatment may not be required, for there is virtually no disability.

If a flexor profundus tendon alone is divided, the flexor superficialis being intact, the loss of active flexion at the distal interphalangeal joint can often be accepted. Attempted repair of the tendon is usually better avoided because of its uncertain results. Arthrodesis of the distal interphalangeal joint in slight flexion reduces the disability to a negligible level.

If both tendons are divided, operative repair or later reconstruction is advised. When the injury is recent (within one week) and the wound clean, and when good conditions and skilled staff are available, primary repair is the method of choice.

Technique. Direct suture of the severed ends demands high technical skill and long experience. Both the superficialis tendon and the profundus tendon should be repaired with loupe magnification, an atraumatic technique, and using semi-absorbable fine 4-0 suture material.

For delayed repair because of late presentation, or where there is extensive damage or loss of tendon tissue, it may be necessary to use a free tendon graft. The standard method is to remove the flexor superficialis tendon entirely (to make more room in the sheath) and to replace the whole of the digital part of the flexor profundus tendon by a free tendon graft (from the palmaris longus or from a toe extensor) sutured proximally to the profundus tendon in the palm or at wrist level, and inserted distally into a drill hole in the distal phalanx (Fig. 16.28). This method eliminates the need for a tendon junction within the sheath, which carries the risk of adhesions that may cause disabling stiffness.

Fig. 16.28 Tendon graft for reconstruction of severed flexor tendons in the digital sheath. Successive stages of the operation are shown in the index, middle, and ring fingers. The use of a free graft eliminates the need for a tendon junction within the sheath.

Division of flexor pollicis longus in the thumb. The problem is less difficult than that presented by division of both flexor tendons in a finger. Repair may be made by direct suture, by advancement of the tendon, or by replacement of the digital part of the tendon by a free graft as described for the fingers.

Division of flexor tendons in the palm or wrist. Direct suture is advised. It may be done primarily if the wound is clean. The prognosis is good if a single tendon is affected but it is uncertain in cases of multiple tendon divisions at the front of the wrist, especially if the nerves are also injured.

Injuries of extensor tendons

Severance of extensor tendons at the back of the hand. This injury has a good prognosis. There is a tendency to spontaneous union with recovery of normal function. Treatment: Primary suture should be undertaken if the injury is recent. If there has been delay, freshening and direct suture of the divided ends is advised. Repair of a spontaneously ruptured extensor tendon in rheumatoid arthritis has a less satisfactory prognosis because the tendon is of impaired quality. Nevertheless, operative repair should usually be attempted.

Rupture of extensor pollicis longus tendon may complicate fracture of the lower end of the radius. The tendon gives way after becoming frayed by repeated movement over the roughened lower end of the radius. Spontaneous rupture may also occur in drummers. The extensive fraying makes direct suture unsatisfactory. Treatment: A clean rupture should be sutured end-to-end. If the tendon is frayed, as is usually the case, a tendon transfer operation is to be preferred. The tendon of extensor indicis is divided at the level of the neck of the second metacarpal bone, re-routed towards the thumb, and sutured to the freshened distal stump of the extensor pollicis longus tendon (Fig. 16.29).

Fig. 16.29 Transfer of extensor indicis to replace a ruptured extensor pollicis longus. The tendon of extensor indicis is divided opposite the neck of the second metacarpal, re-routed towards the thumb, and sutured to the freshened distal stump of the extensor pollicis longus. This transfer is to be preferred to direct suture when the ends of the ruptured tendon are frayed.

Rupture of middle slip of extensor expansion. This is caused by sudden forced flexion of the proximal interphalangeal joint, the middle slip of the extensor expansion being torn from its attachment to the middle phalanx. The patient is unable to extend the proximal interphalangeal joint fully. The distal joint becomes hyperextended. Treatment: The choice lies between immobilisation on a splint in the straight position for three weeks, or operative repair. In a fresh case simple splintage probably gives the better results, though restoration of full function is seldom achieved.

Avulsion of extensor tendon from distal phalanx of a finger. This is known as ‘mallet’ finger or ‘baseball’ finger. It is caused by sudden forced flexion of the distal interphalangeal joint – for instance, by a blow on the tip of the finger from a ball. In a few cases a small fragment of bone is avulsed with the tendon. The patient is unable fully to extend the distal interphalangeal joint (Fig. 16.30). Treatment: Immediate treatment is to splint the finger for three weeks with the distal interphalangeal joint fully extended. Splintage must be continuous and uninterrupted if a good result is to be achieved. The avulsed tendon always unites back to the bone, but often with lengthening, in which case some deformity persists. However, the disability is usually insignificant and acceptable.

Fig. 16.30 Mallet finger (baseball finger). The extensor tendon is avulsed from its insertion. The terminal joint cannot be extended fully.

ACUTE FRICTIONAL TENOSYNOVITIS (Peritendinitis crepitans; paratendinitis crepitans; repetitive stress syndrome)

This is an easily recognised clinical condition common in young adults whose occupations demand repetitive movements of the wrist and hand.

Cause. It is attributed to friction between the tendons and the surrounding paratenon, from over-use of the hand. It is entirely distinct from infective tenosynovitis.

Pathology. The tendons most often affected are those of the deep muscles at the back of the forearm, especially the extensors of the thumb and the radial extensors of the wrist. There is a mild inflammatory reaction about the tendon and its coverings, with local swelling and oedema.

Clinical features. After unusually active use of the wrist or hand over a period of days or weeks pain is felt at the back of the wrist and lower forearm, and swelling is noticed. The pain is aggravated by use of the hand.

On examination there is localised swelling in the line of the affected tendons – usually the extensors of the thumb or wrist. If the examiner’s hand is placed over the swelling while the patient flexes and extends the wrist and digits a characteristic fine crepitation is felt: it is caused by the fibrin-covered tendon gliding within the inflamed paratenon. This typical crepitation is diagnostic of frictional tenosynovitis.

Treatment. Initially, a trial should be made of local injection of hydrocortisone. If this is unsuccessful, the wrist and forearm should be immobilised in plaster of Paris for three weeks, the fingers being left free. This affords sufficient rest to allow the inflammation to resolve. Excessive use of the fingers and thumb should be avoided for two months.

Comment. The condition described above is a distinct clinical entity with incontrovertible evidence of organic pathology. In recent years the label ‘repetitive stress syndrome’ has been applied, too often, to a range of rather vague and purely subjective symptoms affecting the hand, or sometimes the whole arm, in persons occupied for long periods in repetitive tasks such as keyboard operation and computer work. In most such cases it is difficult to separate a genuine physical disability (if indeed it exists at all) from the psychological or ‘functional’ overlay that is often a prominent feature of such conditions.

DE QUERVAIN’S¹ STENOSING TENOVAGINITIS (Tenovaginitis of the abductor pollicis longus and extensor pollicis brevis)

This is a common and well-recognised condition characterised by pain over the styloid process of the radius and palpable thickening in the course of the abductor pollicis longus and extensor pollicis brevis tendons.

Cause. The precise cause is unknown. Excessive friction from over-use may be a factor, because the condition seems prone to follow repetitive actions such as wringing clothes, or in more recent times excessive typing or manipulations.

Pathology. The fibrous sheaths of the abductor pollicis longus and extensor pollicis brevis tendons are thickened where they cross the tip of the radial styloid process. The tendons themselves appear normal as does the synovial lining of the sheath. The condition is possibly analogous to that other common form of tenovaginitis, ‘trigger’ finger (see below).

Clinical features. The condition is five times commoner in women than men, predominantly in middle age. The main symptom is pain on using the hand, especially when movement tenses the abductor pollicis longus and extensor pollicis brevis tendons (as in lifting a saucepan or a teapot). On examination there is local tenderness at the point where the tendons cross the radial styloid process (Fig. 16.31). The thickened fibrous sheaths are usually palpable as a firm nodule. Passive adduction of the wrist or thumb causes the patient to wince with pain.

Fig. 16.31 Site of tenderness in de Quervain’s tenovaginitis.

Treatment. Conservative treatment with rest by splintage, or the injection of hydrocortisone and local anaesthetic into the tendon sheath, produces recovery in over 80 per cent of patients. Where pain and disability continue an operation to divide the thickened sheaths of the affected tendons provides a certain cure.

‘TRIGGER’ FINGER; SNAPPING FINGER (Digital tenovaginitis stenosans)

In this rather common condition thickening and constriction of the mouth of a fibrous digital sheath interfere with the free gliding of the contained flexor tendons.

Cause. This is unknown.

Pathology. The proximal part of the fibrous flexor sheath at the base of a finger or thumb is thickened and the mouth of the sheath is constricted. The contained tendons become ‘waisted’ opposite the constriction, and swollen proximal to it. The swollen segment enters the mouth of the sheath only with difficulty when an attempt is made to straighten the finger from the flexed position (Fig. 16.32).

Fig. 16.32 Mechanism of trigger finger. The swollen part of the tendon is reluctant to enter the constricted mouth of the fibrous sheath when an attempt is made to extend the finger. When sufficient force is exerted it enters with a snap. The thickening forms a palpable nodule at the base of the finger.

Clinical features. The condition occurs:

The adult type. There is complaint of tenderness at the base of the affected finger and of locking of the finger in full flexion (Fig. 16.33). The locking can be overcome either by a strong effort or by extending the finger passively with the other hand, when the flexion is released with a distinct snap. On examination there is a palpable nodule, usually slightly tender, at the base of the affected finger or thumb – that is, over the mouth of the fibrous flexor sheath. The snapping cannot be reproduced well on passive movements; it can be demonstrated only when the patient extends the finger fully with its own muscles or assists extension with the other hand.

Fig. 16.33 Trigger finger. The fingers can be flexed without difficulty A, but when the patient attempts to straighten them the affected finger sticks in the position shown B.

The infantile type (contracted thumb of infants). The infant is unable to straighten the thumb, which is locked in flexion. On examination it may be possible to extend the thumb passively with a snap, but in many cases the flexed position of the joint cannot be corrected even by moderate force. A palpable nodule is present at the base of the thumb in the position of the mouth of the fibrous flexor sheath – that is, at the level of the head of the metacarpal bone. It should be noted that because the deformity is often resistant to correction this condition in infants is often mistaken for a dislocated thumb or for a congenital deformity.

Treatment. Conservative treatment by injection of local steroid at the site of the palpable nodule may sometimes achieve full relief. When this fails both the adult and the infantile type can be cured by the simple operation of incising the mouth of the fibrous flexor sheath longitudinally.

DISORDERS OF THE NECK

Certain disorders of the neck interfere with the brachial plexus or its roots, and thereby produce their predominant symptoms – or even their only symptoms – in the lower arm or hand. By far the commonest of such disorders are osteoarthritis of the cervical spine (cervical spondylosis) and prolapse of a cervical intervertebral disc. Less common as causes of peripheral symptoms are cervical rib, tumours of the spinal column or of the spinal cord, and soft-tissue tumours involving nerves.

TUMOUR AT THE THORACIC INLET

A mass at the thoracic inlet is an occasional cause of peripheral symptoms in the upper limb. The commonest cause is an apical tumour of the lung (Pancoast’s tumour) involving the nerves of the brachial plexus.

DISORDERS OF THE UPPER ARM

Rarely, a disorder of the upper arm may produce its chief effects in the lower arm or hand, usually through the medium of the major nerve trunks. A well- known example is crutch palsy, in which there is weakness or paralysis of the extensor muscles of the wrist, fingers, and thumb from repeated pressure of an axillary crutch upon the radial nerve in the axilla. These complications are avoided if elbow crutches can be used instead of axillary crutches.

DISORDERS OF THE ELBOW

Affections of the elbow may be associated with vague referred pain in the forearm. Almost always, however, the local symptoms in the elbow overshadow the referred symptoms; so mistakes in diagnosis are unlikely.