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Biomedical subjects

R E Field

Publications and source records attributed to R E Field.

16 recordsLinked to original sources
PubMed2006

Five-year prospective clinical and radiological results of a new cannulated cemented polished Tri-Taper femoral stem.

We describe the results at five years of a prospective study of a new tri-tapered polished, cannulated, cemented femoral stem implanted in 51 patients (54 hips) with osteoarthritis. The mean age and body mass index of the patients was 74 years and 27.9, respectively. Using the anterolateral approach, half of the stems were implanted by a consultant orthopaedic surgeon and half by six different registrars. There were three withdrawals from the study because of psychiatric illness, a deep infection and a recurrent dislocation. Five deaths occurred prior to five-year follow-up and one patient withdrew from clinical review. In the remaining 51 hips the mean pre-operative Oxford hip score was 47 points which decreased to 19 points at five years (45 hips). Of the stems 49 (98%) were implanted within 1 degrees of neutral in the femoral canal. The mean migration of the stem at five years was 1.9 mm and the survivorship for aseptic loosening was 100%. There was no significant difference in outcome between the consultant and registrar groups. At five years, the results were comparable with those of other polished, tapered, cemented stems. Long-term surveillance continues.

Aged↗
PubMed2006

Biomechanics of the Birmingham hip resurfacing arthroplasty.

The effects of the method of fixation and interface conditions on the biomechanics of the femoral component of the Birmingham hip resurfacing arthroplasty were examined using a highly detailed three-dimensional computer model of the hip. Stresses and strains in the proximal femur were compared for the natural femur and for the femur resurfaced with the Birmingham hip resurfacing. A comparison of cemented versus uncemented fixation showed no advantage of either with regard to bone loading. When the Birmingham hip resurfacing femoral component was fixed to bone, proximal femoral stresses and strains were non-physiological. Bone resorption was predicted in the inferomedial and superolateral bone within the Birmingham hip resurfacing shell. Resorption was limited to the superolateral region when the stem was not fixed. The increased bone strain observed adjacent to the distal stem should stimulate an increase in bone density at that location. The remodelling of bone seen during revision of failed Birmingham hip resurfacing implants appears to be consistent with the predictions of our finite element analysis.

Arthroplasty, Replacement, Hip↗
PubMed2005

Five-year clinical, radiological and postmortem results of the Cambridge Cup in patients with displaced fractures of the neck of the femur.

The Cambridge Cup has been designed to replace the horseshoe-shaped articular cartilage of the acetabulum and the underlying subchondral bone. It is intended to provide physiological loading with minimal resection of healthy bone. The cup has been used in 50 women with displaced, subcapital fractures of the neck of the femur. In 24 cases, the cup was coated with hydroxyapatite. In 26, the coating was removed before implantation in order to simulate the effect of long-term resorption. The mean Barthel index and the Charnley-modified Merle d'Aubigné scores recovered to their levels before fracture. We reviewed 30 women at two years, 21 were asymptomatic and nine reported minimal pain. The mean scores deteriorated slightly after five years reflecting the comorbidity of advancing age. Patients with the hydroxyapatite-coated components remained asymptomatic, with no wear or loosening. The uncoated components migrated after four years and three required revision. This trial shows good early results using a novel, hydroxyapatite-coated, physiological acetabular component.

Acetabulum↗
PubMed2005

The Oxford hip scores for primary and revision hip replacement.

We have used the Oxford hip score to monitor the progress of 1908 primary and 279 revision hip replacements undertaken since the start of 1995. Our review programme began in early 1999 and has generated 3900 assessments. The mean pre-operative scores for primary and revision cases were 40.95 and 40.11, respectively. The mean annual score for primary replacement at between 12 and 84 months ranged between 20.60 and 22.57. A comparison of cross-sectional and longitudinal data showed no significant differences. All post-operative reviews showed a significant improvement (p < or = 0.0001). The 50- to 60-year-old group scored significantly better than the patients over 80 years of age up to 48 months (p < 0.01). A subgroup of 826 National Health Service (NHS) and 397 private patients, treated by the senior author (2292 Oxford assessments), had a higher (i.e. worse) mean pre-operative score for the NHS patients (p < or = 0.001). The private patients scored better than the NHS group up to 84 months (p < 0.05). Patients treated by a surgeon performing more than 100 replacements each year had a significantly better outcome up to five years than those operated on by surgeons performing fewer than 20 replacements each year. The age of the patients at the time of operation, and their pre-operative level of disability, have both been identified as affecting the long-term outcome. Awareness of the influence of these factors should assist surgeons to provide balanced advice.

Aged↗
PubMed2001

Clinical experience of patellar fracture fixation using metal wire or non-absorbable polyester--a study of 37 cases.

The results of patellar fracture fixation using metal wire and non-absorbable polyester (5 Ethibond) are presented. In group 1 (21 cases), the standard "AO" technique using stainless steel wire was used, and in group 2 (16 cases) we used 5 Ethibond. Patients were assigned to the two groups on surgeon preference. Post-operative management in the two groups was similar, with patients being allowed to mobilise as comfort allowed, under the supervision of the physiotherapists. All patients were followed-up until union of the fractures or until further surgical intervention was carried out. At a mean of 2 years and 6 months (range 1-4 years), we reviewed the notes and X-rays of all 37 cases. In group 2 there were no cases of infection but there were three cases of post-operative infections in group 1. Re-operation rate was 6/21 (38%) in group 1 and 1/6 (6%) in group 2. Therefore, the relative risk of re-operation in the metal group is six times that in the non-absorbable polyester group. The risk of infection in the metal group is also higher. These have implication on patient morbidity associated with the operative treatment of patellar fractures. Non-absorbable polyester appears to compare favourably with the use of metallic wire to fix patellar fractures.

Adult↗
PubMed1995

Reciprocating orthoses for children with myelomeningocele. A comparison of two types.

Since 1987, 22 children with myelomeningocele have been fitted with reciprocating orthoses. The level of the spinal lesions ranged from T10 to L4 and 13 had associated spinal deformities. Twelve of the patients currently use a Reciprocating Gait Orthosis, seven use a Hip Guidance Orthosis or Parawalker, one has progressed to a Knee Ankle Foot Orthosis, one has died and one has been lost to follow-up. The reciprocating orthoses are worn for a mean of 3.5 hours per day (1 to 6.5); daily usage by girls is almost twice that by boys. The mean daily usage by community walkers is 4.2 hours (13 children) as against 2.8 hours by household ambulators (8 children). Active hip flexion is not essential and fixed-flexion contractures up to 35 degrees can be accommodated. The average breakdown rate is 0.45 per year with an average of 1.5 adjustments each year. The average annual cost of a reciprocating orthosis is Aus$750 (375 pounds, US$570); this includes fabrication, adjustments and repairs.

Adolescent↗
PubMed1994

Bone-marrow transplantation in Hurler's syndrome. Effect on skeletal development.

Between 1980 and 1988, displacement bone-marrow transplantation was performed on 25 children with Hurler's syndrome (type-1 mucopolysaccharidosis). We describe the musculoskeletal development of 11 of the 12 surviving children and the orthopaedic procedures undertaken to treat progressive thoracolumbar kyphosis, hip subluxation and carpal tunnel syndrome. We found abnormal bone modelling, focal failures of ossification and an avascular disorder of the femoral head in every patient and offer an explanation for these phenomena. Increasing valgus deformity of the knees and progressive generalised myopathy caused loss of mobility as the children entered adolescence. The benefit of bone-marrow transplantation as a treatment for the skeletal disorders of Hurler's syndrome is limited by the poor penetration of the musculoskeletal tissues by the enzyme derived from the leucocytes.

Bone Marrow Transplantation↗
PubMed1993

The Victoria bomb: a report from the Westminster Hospital.

On 18 February 1991 a bomb exploded on Victoria station, London. A total of 51 people were injured including one fatally. Of the most seriously wounded, 30 were treated at The Westminster Hospital. The majority of injuries were to the lower limbs, but serious wounds were also sustained to the chest, abdomen, forearm, orbit and cranium. Almost all injuries were caused by shrapnel. The low incidence of infection was attributed to thorough early surgical débridement. The administration of antibiotics was varied and uncoordinated, reflecting a lack of a common policy. The exhaustion of common external fixators necessitated the use of equipment unfamiliar to the surgeons and underlined the need for the rapid transfer of equipment between hospitals at the time of major incidents.

Adolescent↗
PubMed1990

Bone density distribution within the femoral head and neck. An examination by high-resolution computed tomography.

The upper portions of three cadaveric femora were examined by high-resolution computed tomography. Analysis of the resulting images provided both quantitative and spatial distributions of bone density within the femoral head and neck. The information obtained provides new insights into aspects of proximal femoral architecture for both normal and osteoporotic bone. The study also points the way towards a clinical technique for measuring the material properties of proximal femoral bone.

Absorptiometry, Photon↗
PubMed1989

A mathematical analysis for the modelling of trabecular bone.

We present a mathematical analysis of trabecular bone which may be applied to develop dynamic computer simulations of the musculoskeletal system. We have derived an algorithm which can be used to study the genetic limitations within which skeletal articulations may function successfully. We believe that our model will help other workers to advance the understanding of the interplay between genetic and environmental influences in the growth, modelling and degeneration of osseous tissues.

Animals↗
PubMed1989

Proximal femoral surface strain gauge analysis of a new epiphyseal prosthesis.

This paper describes a new type of proximal femoral, replacement arthroplasty and its preliminary, pre-clinical, evaluation. The prosthesis was designed as a replacement for the femoral capital epiphysis. It comprises a thin, metal, articular shell and an underlying 'epiphyseal' replacement which is modulus-matched to adjacent proximal femoral bone. Surface strain gauge analysis of the proximal femur under conditions simulating static single leg stance demonstrated that the new prosthesis maintains an essentially normal femoral strain distribution. It is hoped that selective load transmissions across the prosthesis-bone interface should result in less post-implantation proximal bone resorption.

Hip Prosthesis↗
PubMedDate not supplied

Metastatic carcinoma of breast simulating Crohn's disease.

A 52-year-old female had radical surgery on both breasts in 1971 and 1973 for infiltrating lobular carcinoma of the breast. One year later, multiple metastases simulating Crohn's disease were found radiologically and intraoperatively in the colon and small bowel. The pathological examination revealed multiple areas of linitis plastica type carcinoma in the colon and small bowel. Review of the breast slides showed that the original breast carcinoma was morphologically identical to the metastatic lesions. The literature is reviewed and arguments are presented to attest that signet-ring-cell carcinoma of the breast is a distinct entity, which not too infrequently metastasizes to the gastrointestinal tract.

Adenocarcinoma↗