CHAPTER 7 The hand
Note that the separation of conditions into those affecting the wrist and those affecting the hand has been done for convenience, and that in many cases examination of both regions is necessary.
Vibration Syndromes
Prolonged exposure to high-frequency vibration (such as may be experienced from the use of jack hammers or hand-held buffing, riveting and caulking machines) may affect bone, nerves and blood vessels. Bone is rarely affected to a significant degree, but new bone formation and hairline fractures (which are slow to heal) are sometimes seen. Involvement of the peripheral nerves may lead to pain and paraesthesia, numbness, tremor, loss of fine touch sensation, proprioception and discrimination. There may be muscle denervation and weakness involving especially the small muscles of the hand. In the case of the peripheral blood vessels there is disturbance of their autonomic control, and the arterioles of the hand become hypersensitive to cold and vibration. In the typical case there are attacks in which one or more fingers turn white on exposure to cold (‘episodic blanching’), with reactive hyperaemia on warming; and there is usually associated discomfort and clumsiness of the hand during attacks. As the condition progresses more fingers become involved, incidents occur both in summer and in winter, and hand function becomes permanently disturbed. The hand becomes weak and clumsy, and with impaired sensation and proprioception the patient has difficulty in dressing (e.g. doing up buttons and shoelaces), handling small objects (e.g. coins, nuts and screws), and carrying out many other tasks (e.g. tying fishing hooks). The differential diagnosis includes Raynaud’s disease, cervical rib and the costoclavicular syndrome, cervical spondylosis, and sensitivity to β-blockers.
There are a number of classifications of the stages of the condition, and the long-established Taylor–Pelmear scale is still widely used (Table 7.1). Well established cases are recognised as one of the prescribed diseases under the Social Security Act, and the qualifying criteria are clearly stated. (The condition must occur throughout the year, involve at least three fingers of one hand (with the middle and/or proximal phalanges being affected), and be due to exposure to vibrating tools.) No treatment is effective, but deterioration may be slowed or prevented by avoiding further exposure to vibration.
Stage | Condition of digits | Work and social interference |
---|---|---|
0 | No blanching of digits | No complaints |
0T | Intermittent tingling | No interference with activities |
0N | Intermittent numbness | No interference with activities |
1 | Blanching of one or more fingertips, with or without tingling or numbness | No interference with activities |
2 | Blanching of one or more fingers, with numbness; usually confined to winter | Slight interference with home and social activities; no interference at work |
3 | Extensive blanching. Frequent episodes, summer and winter | Definite interference at work, at home, and with social activities. Restriction of hobbies |
4 | Extensive blanching. Most or all fingers affected. Frequent episodes, summer and winter | Occupation changed to avoid further exposure to vibration because of severity of signs and symptoms |
Tendon and Tendon Sheath Lesions
See also under Rheumatoid arthritis.
Mallet thumb
Delayed rupture of the extensor pollicis longus tendon may follow Colles’ fracture (see Ch. 6) or rheumatoid arthritis, and repair by tendon transfer (using extensor indicis proprius) is usually advised. If the tendon is damaged by an incised wound, repair by direct suture is undertaken.
Boutonnière deformity
Flexion of the interphalangeal joint of a finger with extension of the distal interphalangeal joint characterises this deformity, which is due to detachment of the central slip of the extensor tendon which is attached to the base of the middle phalanx. This may follow incised wounds on the dorsum of the finger and avulsion injuries, but is more commonly seen in rheumatoid arthritis. Surgical repair of the extensor band is often undertaken for isolated lesions of this type.
Profundus tendon injuries
Rheumatoid Arthritis
In the earliest stages of the disease, medications which have analgesic, anti-inflammatory and antiautoimmune effects may be prescribed, with the judicious use of physiotherapy and splintage to alleviate pain, preserve movement and minimise deformity. When there is much synovial thickening at a stage before joint destruction has advanced, synovectomy is often helpful in alleviating pain and delaying local progress of the condition. In a few well selected cases, where there is severe joint destruction and progressive deformity, joint replacement may be helpful; some cases of major tendon involvement may benefit from repair and other procedures.