wrist

CHAPTER 6 The wrist



Study of the wrist cannot be separated from that of the hand, and in many cases careful examination of both may be required.



Complications Occurring After Colles’ Fracture


Considering the incidence of Colles’ fracture, the commonest of all fractures, it is surprising that complications from this injury are not seen more frequently; nevertheless, they do occur and are of importance. Excluding initial weakness of the wrist, the commonest complaints are of residual deformity, restriction of movements and pain.


The common deformities are radial deviation of the hand and prominence of the ulna. Owing to resorption of bone at the fracture site during healing, there is shortening of the radius with radial deviation of the hand. This may be aggravated by a poor reduction. At the back of the wrist, the head of the ulna becomes prominent. (Gross subluxations of the ulna of this pattern are sometimes referred to as Madelung’s deformity; this term was used initially to describe a condition occurring in adolescents where, following some disturbance of growth in the distal radial epiphysis, often idiopathic in origin, the ulna becomes relatively prominent.)


In all Colles’ fractures there is disturbance of the inferior radioulnar joint. In some cases this is responsible for persisting pain and tenderness just lateral to the ulnar styloid.


Again, disruption of the inferior radioulnar joint is partly responsible for loss of movements in the wrist. This certainly accounts for the loss of supination that causes patients the greatest concern. Although restriction of dorsiflexion occurs after most Colles’ fractures, this seldom gives rise to any functional problems.


Two other important complications are seen after Colles’ fracture: (a) delayed rupture of extensor pollicis longus tendon may occur some months after injury and is due to ischaemia or attrition of the tendon, and (b) Sudeck’s atrophy (complex regional pain syndrome), which is usually diagnosed some weeks after cast fixation has been discontinued, and which is characterised by marked swelling of the wrist, hand and fingers, gross stiffness of the fingers, and decalcification of the carpal bones which is obvious on radiographs of the region.


Regarding treatment of these complications, the patient is generally advised to accept minor degrees of residual deformity and stiffness. When there is gross prominence of the ulna causing symptoms, excision of the distal end of the bone may be advised. Ruptures of extensor pollicis longus are treated by tendon transfer (extensor indicis proprius is generally employed). Sudeck’s atrophy generally requires intensive physiotherapy, and often other measures if much permanent stiffness is to be avoided.









Carpal Tunnel Syndrome


This condition occurs most commonly in women in the 30–60-year age group. Basically there is compression of the median nerve, which leads to symptoms and signs related to its distribution. In some cases premenstrual fluid retention, early rheumatoid arthritis with synovial tendon sheath thickening, and old Colles’ or carpal fractures may be responsible by restricting the space left for the nerve in the carpal tunnel. The condition is sometimes seen in association with myxoedema, acromegaly and pregnancy; often, however, no obvious cause can be found, and it is very frequently bilateral. The patient complains of paraesthesia in the hand: often all the fingers are claimed to be involved, although theoretically at least the little finger should always be spared. Paraesthesia may also radiate proximally to the elbow. There may be pain in the same areas, and weakness in the hand. The symptoms may become most marked in the early hours of the morning, often waking the patient from sleep and causing her to shake the hand or hang it over the side of the bed. In many cases the history and results of the clinical examination are unequivocal. In others it may be difficult to differentiate the patient’s symptoms from those produced by cervical spondylosis, and indeed both conditions may be present at the same time; a trial period of immobilisation of the wrist in a cast or the use of a cervical collar may be helpful. Nerve conduction-time tests, showing a delay at the wrist, may be used to confirm the diagnosis. These studies are being employed with increasing frequency in the practice of defensive medicine.


Most cases are treated quite simply by division of the flexor retinaculum, which forms the roof of the carpal tunnel, thereby relieving pressure on the nerve; the procedure may be performed arthroscopically through a minimal incision. Conservative measures may be tried, especially in cases occurring in pregnancy, when diuretics may be prescribed with success. Other measures include the use of night splints and injections of hydrocortisone.


Note that on rare occasions the median nerve may be compressed proximal to the carpal tunnel. Above the elbow this may be due to a supracondylar bony spur (obvious on radiographs); just distal to the elbow, by the origin of pronator teres; and in the proximal part of the forearm by the sublimis. Proximal lesions of the median nerve give rise to the anterior interosseous nerve syndrome.






Carpal Instabilities


A carpal instability is a condition in which there is a loss of normal carpal alignment which develops at an early or a late stage after an injury. Untreated cases may lead to the development of osteoarthritis in the wrist.


In static carpal instabilities there is an abnormal carpal alignment, which can be seen by careful study of standard AP and lateral radiographs of the wrist.


In dynamic carpal instabilities routine radiographs are normal. The patient is usually able to toggle his carpal alignment from normal to abnormal and back. To establish the diagnosis in this situation, lead markers may be placed on the skin over points of local tenderness, and radiographs taken in both stable and unstable positions.


In the case of scapholunate instability (scapholunate dissociation), the commonest of these problems, AP views of the supinated wrist in both radial and ulnar deviation are usually diagnostic. Other investigations include examination of the wrist in motion using an image intensifier and radioisotope bone scans.


Acute cases may be stabilised by manipulative reduction and the insertion of K-wires, or by ligamentous repair. In chronic cases reattachment of the avulsed ligaments may be carried out, but where there are arthritic changes and subluxation a salvage procedure may have to be considered.






Jun 5, 2016 | Posted by in ORTHOPEDIC | Comments Off on wrist

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