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Biomedical subjects

J Wilson-MacDonald

Publications and source records attributed to J Wilson-MacDonald.

At least 19 recordsLinked to original sources
PubMed2005

Epidural steroid injection for nerve root compression. A randomised, controlled trial.

We have assessed whether an epidural steroid injection is effective in the treatment of symptoms due to compression of a nerve root in the lumbar spine by carrying out a prospective, randomised, controlled trial in which patients received either an epidural steroid injection or an intramuscular injection of local anaesthetic and steroid. We assessed a total of 93 patients according to the Oxford pain chart and the Oswestry disability index and followed up for a minimum of two years. All the patients had been categorised as potential candidates for surgery. There was a significant reduction in pain early on in those having an epidural steroid injection but no difference in the long term between the two groups. The rate of subsequent operation in the groups was similar.

Adult↗
PubMed2001

Instability due to unrecognised fracture-subluxations after apparently isolated injuries of the cervical spine.

Instability may present at a different level after successful stabilisation of an unstable segment in apparently isolated injuries of the cervical spine. It can give rise to progressive deformity or symptoms which require further treatment. We performed one or more operations for unstable cervical spinal injuries on 121 patients over a period of 90 months. Of these, five were identified as having instability due to an initially unrecognised fracture-subluxation at a different level. We present the details of these five patients and discuss the problems associated with their diagnosis and treatment.

Accidents, Traffic↗
PubMed1996

Bone growth and remodelling after fracture.

We used a rabbit model to investigate the mechanism by which the angulation of fractures is corrected in children. We produced a transverse proximal tibial fracture in one leg of 12 eight-week-old New Zealand white rabbits and measured bone alignment and length and the patterns of bone growth and remodelling. The angle between the joint surfaces changed rapidly to correct the alignment of the limb as a result of asymmetrical growth of epiphyseal plates. In an adult with closed plates, the angle between the joint surfaces cannot therefore improve. The angle at the fracture itself showed slow improvement because of bone drift and the asymmetrical growth of the epiphyseal plates. Remodelling corrected the shape of the bone in the region of the fracture. Periosteal division on the convex side increased the growth of the epiphyseal plate on that side, thus slowing the correction. The effect was relatively small, providing an indication that factors other than the periosteum are important in inducing correction. External torsional deformities developed because of helical growth at the plate. This was probably caused by abnormal posture which induced a torque at the growth plate. Helical growth is the mechanism by which rotational deformities can occur and correct.

Age Factors↗
PubMed1995

A complication of spinal decompression. A case report.

STUDY DESIGN: This case study is designed to report the previously unreported specific complication of acute cauda equina compression after decompression surgery for spinal stenosis. OBJECTIVES: To inform others of the possibility of such a complication; to suggest a possible mechanism for this situation, namely hourglass constriction of the cauda causing ischemia to distal nerve roots; and to suggest a management plan--immediate magnetic resonance imaging to identify the problem and return to the operating room for further decompression--which was successful in this case. SUMMARY OF BACKGROUND DATA: Previous reports of causes of paraparesis or paraplegia after surgery are listed, and previous theories on the etiology of acute cauda compression are discussed. METHODS: The clinical findings of spinal stenosis in a 32-year-old man are presented, and subsequent details of the surgery, complications after surgery, investigation, and future surgery, including magnetic resonance imaging scans before and after surgery, are provided. RESULTS: The result in this case was a patient free of symptoms. CONCLUSIONS: Incomplete decompression in surgery for spinal stenosis can result in acute cauda equina compression. In these circumstances, magnetic resonance imaging can reveal the cause, and in this case, immediate surgery was successful in relieving the symptoms and signs.

Acute Disease↗
PubMed1995

Acute MRI changes in infectious discitis: report on two cases.

Previous reports suggest that MRI changes should be seen within 48h of symptoms arising. We report on two patients with proven discitis at the L5/S1 disc. MRI performed within 60h of the onset of symptoms did not demonstrate evidence of infection and therefore did not confirm the diagnosis of discitis. The reliability of early MRI to confirm infective discitis is questionable. The cases we report on did not display any of the typical changes of discitis on MRI within the first 48h after the onset of symptoms. Absence of typical infective changes on MRI does not necessarily exclude an infection within the disc space.

Adult↗
PubMed1994

Day case arthroscopy under local anaesthesia.

A prospective study of the effectiveness of local anaesthesia in arthroscopy of the knee was performed in 212 consecutive patients. Arthroscopic surgery was undertaken successfully in 121 cases (57%), including meniscectomy and drilling of osteochondral defects. Dynamic evaluation of the patellofemoral joint articulation was possible and demonstration of pathological abnormalities was felt to be beneficial by some patients. The method described is safe, reliable, confers good postoperative analgesia and enables physiotherapy to begin immediately. Conversion to general anaesthesia was necessary in one case due to pain localised to a stiff and osteoarthritic hip. Intra-articular haemorrhage was found to be a problem in one case with synovitis. Only ten patients complained of moderate pain, none had severe pain. Local anaesthesia is contraindicated in cases with ipsilateral osteoarthritis of the hip or with significant synovitis of the knee. This technique is particularly suited to day case surgery.

Ambulatory Surgical Procedures↗
PubMed1992

The modified Mayo procedure combined with basal valgus osteotomy of the first metatarsal for severe hallux valgus.

The modified Mayo procedure corrects valgus deformity of the great toe secondary to osteoarthritis in the first metatarsophalangeal joint. Basal osteotomy of the first metatarsal to correct metatarsus primus varus and to maintain correction of the valgus deformity may be performed simultaneously. We retrospectively reviewed the results in 55 of 70 feet treated by this combined procedure. The average duration of follow-up was 4.2 years (range 0.5-6 years) and the average age at operation was 63 years (range 45-80 years). The results were either very good or good in 82%, moderate in 14%, and poor in 4%. Our technique of basal osteotomy of the first metatarsal is a simple and effective procedure to correct metatarsus primus varus and may restore the distal transverse arch. It should be considered as a possible method of treatment when the intermetatarsal angle is greater than 10 degrees.

Adult↗
PubMed1990

Comparison between straight- and curved-stem Müller femoral prostheses. 5- to 10-year results of 545 total hip replacements.

Between 1977 and 1982, 545 cemented femoral prostheses were implanted, in combination with a noncoated cementless polyethylene acetabular component (RM cup). Three hundred and eighty-one straight-stem and 76 curved-stem Müller femoral components were implanted, as well as 88 collared components with a 130-mm stem and a 130 degrees neck-shaft angle, derived from a long-stem steel prosthesis. Survivorship analysis of revisions for aseptic loosening at 10 years revealed 97% straight-stem survival, 91.6% curved-stem survival, and 88.3% 130 degrees stem survival. "Survival" curves were also constructed for radiological loosening, and the survival rates (patients without radiological evidence of loosening) were 69.8%, 78.8%, and 63.1% respectively at 10 years. The 130 degrees collared stem was associated with significantly less acetabular loosening than the other prostheses. This resulted in less calcar resorption, but there was a higher rate of stem loosening. Acetabular loosening and associated wear products appear to be responsible for calcar resorption, and stress shielding of the calcar appears to be of minor importance in the pathogenesis of aseptic stem loosening. Better cementing techniques have improved survivorship of the curved-stem prosthesis, and early fears of high rates of radiological loosening with the straight stem have not been substantiated.

Adult↗
PubMed1990

Arthroscopy in acute knee injuries: a prospective controlled trial.

Eighty-two patients took part in a prospective trial to assess the need and timing for arthroscopy in acute knee injuries. Patients with a suspected ligament injury, a suspected meniscal tear, or a haemarthrosis in the absence of fracture were included in the trial. Patients were entered randomly into two groups. In group I early arthroscopy was performed (within 48 h), in group II arthroscopy was performed within 21 days, but only when it was felt to be clinically indicated. Patients were assessed using the OAK knee score 1 year after the injury. There was no difference in the final result between the two groups. Early arthroscopy (within 48 h) showed no beneficial effect when compared with delayed arthroscopy (3 to 21 days after the injury). Indeed, an important diagnosis was missed at early arthroscopy in three cases, which led to delay in subsequent diagnosis and treatment. Arthroscopy raised the diagnostic accuracy from 61 per cent to 93 per cent. Considerable morbidity arises as a result of acute knee injuries. Clinical judgment will correctly define the need for arthroscopy in most cases at the time of injury, and arthroscopy is not necessary in all cases of acute haemarthrosis.

Acute Disease↗
PubMed1990

The relationship between periosteal division and compression or distraction of the growth plate. An experimental study in the rabbit.

We subjected the proximal tibial growth plates of six-week-old rabbits to either compression or distraction of 1 kg on both legs. On one side the proximal tibial periosteum was divided circumferentially and stripped for 1 cm. After six weeks, growth was measured at both proximal and distal growth plates. Compression inhibited total tibial growth and distraction enhanced it. The compressed growth plate grew less and the distracted growth plate grew more, but there was a reciprocal change at the other end of the bone. Periosteal division enhanced growth at the adjacent growth plate but inhibited it distally; the effect of distraction was enhanced and that of compression reduced. We found reciprocal growth rates at the proximal and distal growth plates. Relatively small amounts of compression or distraction did affect total bone growth. Periosteal division appeared to induce overgrowth at least partly by a mechanical effect; it may be useful as an adjunct to other methods of leg lengthening, though not to epiphyseolysis.

Animals↗
PubMed1990

Cementless uncoated polyethylene acetabular components in total hip replacement. Review of five- to 10-year results.

We reviewed the results of 545 consecutive total hip replacements using a cementless non-coated high-density polyethylene acetabular component combined with a cemented Müller stem at five to 10 years. In all, 421 patients (445 hips) were available for review, 118 by questionnaire and 303 by examination and radiography. Of these, 86% had a good or excellent result. We found a high rate of radiological loosening of the cup after the sixth year, and a high rate of clinical loosening after the eighth year. Loosening was commoner in women, in younger patients and where a smaller size of acetabulum had been used. Calcar resorption was significantly related to loosening of the acetabulum. Loosening appeared to be mainly due to polyethylene debris produced by micro-movement of the acetabulum against the bone, which had resulted in a giant cell foreign body reaction and subsequent bone erosion. We have abandoned the use of this prosthesis and suggest that direct contact between bone and polyethylene should be prevented by a coating of metal or some other material.

Acetabulum↗
PubMed1990

Total arthroplasty in Paget's disease of the hip. A clinical review and review of the literature.

The results in 30 Paget's disease patients with 37 affected hips treated with total hip arthroplasty (THA) for symptomatic coxarthrosis were compared with the results of previously reported series. Metabolic activity of the disease subsequent to surgery seemed to have no effect on the clinical outcome during 7.8 years of follow-up study; location of the disease (acetabulum only, femur only, or both) or the presence of protrusio alone also had no effect. For the femur, failure rates were similar for prostheses implanted in Pagetic or non-Pagetic bone. Good results can be anticipated for patients with Paget's disease treated with cemented THA.

Aged↗
PubMed1988

Bilateral avulsion fractures of the cranial margin of the scapula.

Avulsion of the cranial margin of the scapula is a rare injury. A case of bilateral avulsion fractures is reported. The postulated mechanism of injury is a powerful contraction of the omohyoid muscle avulsing its insertion. Conservative management was successful.

Accidents, Traffic↗
PubMed1988

Fatal paradoxical thrombo-embolism during anaesthesia.

Deep venous thrombosis is a recognised complication of trauma to the leg and may lead to pulmonary thrombo-embolism, but paradoxical thrombo-embolism is rare. A case of fatal paradoxical thrombo-embolism which followed a leg injury in a previously fit 36-year-old male is presented and contributory factors are reviewed.

Adult↗