Biomedical subjects
Publications and source records attributed to R A Dickson.
A study of the incidence and grading of osteoarthritis in all the other thirty-two joints in the hands of twenty-one patients with osteoarthritis of the carpometacarpal joint of the thumb.
We report a detailed study of the relative distribution of joint damage, as assessed by erosion and joint space scores, in the proximal interphalangeal (PIP) and metacarpophalangeal (MCP) joints of the rheumatoid hand. Hand radiographs of 30 patients with erosive rheumatoid arthritis were studied. There was significantly more damage in the dominant hand. The little-finger PIP joints were more damaged and the thumb interphalangeal (IP) joints less damaged than the other PIP joints. The index and middle finger MCP joints were more damaged than the other MCP joints. There was a significant negative correlation between the erosion scores of the PIP and MCP joints of each individual digit, when digits with only minimal damage were excluded. These findings support the concept that joint damage in the rheumatoid hand is greater in those joints that are subjected to greater mechanical stresses, and that in any digital ray the damage is concentrated at either the IPI or MCP joint.
Musculoskeletal disease in the community is common, and much of it responds to early diagnosis and preventive care. At the same time, modern orthopaedics, like so many specialist subjects, has increased significantly in depth and detail pari passu with its advances. It therefore becomes all the more important in desiging undergraduate teaching programmes in these specialist subjects to provide a comprehensive basic training programme that is flexible enough to move with the specialty. The orthopaedic undergraduate education programme in Oxford meets these requirements, embraces all aspects of the subject, and enables the medical student to examine the musculoskeletal system with confidence to interpret his findings, without making him an embryo specialist.
Standardised radiographs of the weight-bearing foot were analysed in fifty young patients undergoing osteotomy of the first metatarsal for hallux valgus. True metatarsus primus varus was not found more frequently than in a control series. The intermetatarsal angle was significantly greater in affected feet compared with controls. The structural abnormality in hallux valgus in the young is therefore due to a valgus disposition of the second and subsequent metatarsals, rather than varus inclination of the first metatarsal.
Sixty patients with congenital deformities of the spine were operated upon in the past fifteen years using a two-stage procedure. In the fifty patients with scoliosis half of the deformities were due to hemivertebrae and half to unilateral bars. The average correction of the deformity was 47 per cent. Early neurological signs observed in two patients with a diastematomyelia resolved. Of the ten patients with kyphosis nine had neurological signs of impending paraplegia and one was completely paraplegic before operation; all improved markedly. Posterior spinal fusion alone in the rapidly progressing congenital deformity may not prevent further progression, particularly in those cases iwth unilateral bars. Anterior resection of the vertebral body with later posterior fusion with Harrington instrumentation is safe and effective.
Tension introduced into peripheral nerves during their surgical repair may reduce the success of this procedure. Two mechanical factors are important; the tension required to effect a repair, and the rate at which this tension changes after surgery. These two factors have been investigated in the rat sciatic nerve. The results show an increasing resistance to elongation of the nerves with increasing tension. Under a constant elongation the tension in the nerves reduces by about 30 per cent in the first 10 minutes and by a small amount in the following 20 minutes.
Bone density was studied in ten patients before and after release of an idiopathic carpal tunnel syndrome. A corticomedullary ratio was measured at the mid-point of the metacarpals and proximal phalanges of both hands. There was a significant increase in the mean bone density over the period of observation in the thumb and middle finger metacarpals and in the index, middle, and ring finger proximal phalanges of the operated hand. There was no significant increase in the density of either metacarpal or proximal phalanx on the non-operated side. Release of the carpal tunnel syndrome provides not only symptomatic relief but also leads to increased bone density.
Injuries of the spine have been seen in cases of child abuse. These injuries can be identified by careful skeletal survey. In the case described, a young boy was originally diagnosed as having dorsolumbar kyphus with no previous trauma, but the injury was later found to be related to parental abuse. The most important condition to rule out is spinal infection. The parental behavioral history is important, and social work consultation is recommended.
Sixteen severely haemophilic patients have undergone arthrodesis of one joint of the lower limb in the period 1966 to 1976. There have been nine arthrodeses of the knee and seven of the ankle. The follow-up period was from nine months to eight years. The arthrodeses were secured by internal fixation. The method was not without complications, but a satisfactory bony union resulted in all cases without further surgical intervention.
Congenital spinal extradural cysts are rare and may be the cause of acute paraplegia. In their clinical features they closely resemble acute transverse myelitis. Immediate decompression of the spinal cord and removal of the cyst may lead to restoration of normal function. Myelography differentiates these two conditions by showing a cyst in communication with the spinal canal. This investigation must be mandatory.
A pilot study of ten individuals with adolescent-onset idiopathic scoliosis demonstrated that a week of Cotrel traction and exercises did not improve curve correction obtained by the application of an elongation, derotation, flexion (EDF) cast. There was, however, a significant improvement on lateral bending correction during this period. A prospective, randomized, controlled clinical trial showed that the exercise programme and not the traction was responsible for rendering the spine less rigid.
The deforming mechanisms in the congenital lumbar kyphosis of myelomeningocele are situated anteriorly. Posterior wedge resection with local fusion therefore will not prevent progression of the deformity. Nonetheless, this procedure may be the only method of affording sac closure, or providing continuity of the ulcerated integument. Definitive corrective surgery will be required later and must combat the anterior deforming forces. Resection of the apical vertebral body followed by posterior fusion with Harrington instrumentation provides a solid straight spine.
Interfascicular nerve grafts allowed to undergo endoneurial tube emptying in situ before transfer have been compared with grafts transferred fresh in terms of structure and function. The sciatic nerve of the rat was the model and its structure and ultrastructure were superior following degenerate grafting. More importantly, electrophysiological studies showed that function in nerves repaired with degenerate grafts was significantly better than in those repaired with fresh grafts.
Following the successful treatment of knee-flexion contractures in haemophiliacs using an external corrective system with reversed dynamic slings, these have been adapted to treat post-traumatic elbow contractures. A case is described in which 90 degrees of fixed flexion was corrected in 1 week without discomfort. Clearly there is no need to resort to an internally applied hinge-distractor apparatus or capsulectomy if a simple external sling system is successful without complications.
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Some common surgical procedures, practised to improve the function of the rheumatoid hand, have been subjected to a prospective and objective evaluation. This analysis has been based on the concept of the assessment of hand function by measurement of individual digital forces and the results clearly justify surgical intervention. In addition, function is improved in those digits belonging to the hand operated upon but not themselves undergoing surgery.
Although high pressure injection injuries of the hand are frequently described, little is known about the mechanism of tissue necrosis. A case is described which led to digital amputation and the clinical features are discussed in relation to others reported. The digit was examined histologically and a sample of liquid drained from the palm was subjected to organic chemical analysis. The findings of widespread vessel thrombosis, absence of fat from fat loculi, and coagulative necrosis of skin and subcutaneous tissue becoming less marked the more proximal in the digit suggest a chemical inflammatory cause. This is supported by chemical analysis revealing a fat solvent as the chemical agent and fat degradation products in the palmar liquid.