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W J Gillespie

Publications and source records attributed to W J Gillespie.

At least 55 records · Page 3Linked to original sources
PubMed1990

Economic appraisal of new technology in the absence of survival data--the case of total hip replacement.

The development of total hip replacement has reached a level at which little further improvement in pain relief or quality of life can be expected from the introduction of new prosthetic technology. Rather, it is reasonable to expect longer trouble-free prosthetic life. This paper develops a mathematical model for a comparative economic appraisal of two types of prostheses, the conventional cemented one and the new cementless one. The lack of reliable survivorship data precludes reaching definite conclusions. However, by extensive sensitivity analysis with respect to a number of cost parameters the model can be used to derive conditions under which the cementless prosthesis is more cost effective. Expert medical judgement can then be used to gage whether these conditions are likely to be satisfied. The paper highlights the importance of collecting statistically valid performance data on any new medical technology from its first introduction. Without these, its full-scale adoption will be based largely on subjective grounds rather than a proper cost benefit analysis. It finally shows how both aspects--economic modeling and scientific data collection--form part of an integrated management programme for the economic evaluation of new medical technology.

Acrylates↗
PubMed1990

Mechanisms of bone degradation in infection: a review of current hypotheses.

Bone infection in clinical practice results in loss of structural integrity, leading to complications such as fracture and implant loosening. The biology of this process has received relatively little attention. In experimental models it seems clear that both polymorphonuclear leukocytes, whose effect predominates in the early stages, and mononuclear phagocytes are capable of bone degradation. An indirect effect by stimulation of physiologic mechanisms of resorption has not been ruled out, but the evidence points to direct degradation by inflammatory cell enzymes.

Animals↗
PubMed1990

Soluble products of Staphylococcus aureus-stimulated blood mononuclear cells in enhancing polymorphonuclear leukocyte degradation of bone.

Rapid, extensive loss of infected bone implies abnormal localized inflammatory cell activity. We have demonstrated, using a live bone Ca-45 release model, that polymorphonuclear leukocytes degrade bone in a dose dependent manner. Staphylococcus aureus-stimulated blood mononuclear leukocytes release soluble products in vitro that enhance that process. Despite the usually accepted roles of osteoclasts and their blood-borne monocytic precursors in normal bone remodelling, these results indicate that considerable early pathological infected bone loss may be attributable to inflammatory polymorphonuclear leukocytes.

Animals↗
PubMed1990

Epidemiology in bone and joint infection.

The studies of community-acquired infection indicate the importance of the environment in which the host-pathogen interaction takes place. Whereas the high incidence rates at the extremes of life are compatible with a hypothesis of diminished immune competence, the varying rates of acute osteomyelitis during growth, and its predominantly metaphyseal site, suggest that further studies of the molecular biology of this rather specific infection would be revealing. Molecular biology has a role, too, in improving understanding of the epidemiology of resistance and pathogenicity in hospital-acquired infections. Although antibiotic prescription and other medical practices influence the environment profoundly, we should remember that we may be experiencing long-term trends beyond our present understanding. As more and more reconstructive bone and joint surgery is carried out, careful observational epidemiology remains a vital tool.

Arthritis, Infectious↗
PubMed1990

Infection in total joint replacement.

Although a small number of infections in total joint replacements are blood borne from distant sources, most infections appear to have been derived at operation. Strenuous attempts to reduce this risk by cleaning the air in the wound environment, coupled with prophylactic antibiotics, have reduced infection rates by an order of magnitude in a decade. During that time the potential for exchange arthroplasty in established infection has been shown, and the results are encouraging. Rigorous infection control is the key to containing this difficult and expensive problem.

Anti-Bacterial Agents↗
PubMed1989

Leg blood flow during total hip replacement under spinal or general anaesthesia.

Calf blood flow was studied using venous occlusion impedance plethysmography during 122 total hip arthroplasties. Patients were randomly allocated to receive spinal or general anaesthesia. Blood flow was measured nine times perioperatively. In the non-surgical leg, mean blood flow rose by over 50% in both groups following anaesthetic induction, remaining significantly elevated with spinal but falling back gradually to baseline with general anaesthesia. In the surgical leg, surgical manipulations produced marked falls in flow in many patients, particularly with femoral component insertion. If this occurred, hyperaemia was commonly seen with spinal anaesthesia but rarely with general anaesthesia once the joint was relocated. Venous outflow resistance rose slightly during anaesthesia in both groups, more so with general anaesthesia. In the surgical leg, marked rises occurred with surgical manipulations, but resistance fell abruptly once the joint was relocated. No clear relationship between these observations and the occurrence of deep vein thrombosis postoperatively was established.

Anesthesia, General↗
PubMed1989

Deep vein thrombosis after total hip replacement. A comparison between spinal and general anaesthesia.

The effect of hypobaric spinal anaesthesia or narcotic-halothane-relaxant general anaesthesia on the incidence of postoperative deep vein thrombosis was studied in 140 elective total hip replacements in a prospective randomised manner. Deep vein thrombosis was diagnosed using impedance plethysmography and the 125I fibrinogen uptake test, combined, in selected cases, with ascending contrast venography. The overall incidence of deep vein thrombosis was 20%. Nine patients (13%) developed deep vein thrombosis in the spinal group and nineteen (27%) in the general anaesthetic group (p less than 0.05). The incidences of proximal thrombosis and of bilateral thrombi were also less with spinal anaesthesia than with general anaesthesia. It is concluded that spinal anaesthesia reduces the risks of postoperative thromboembolism in hip replacement surgery. The presence of varicose veins, being a non-smoker and having a low body mass index were associated with an increased incidence of deep vein thrombosis.

Aged↗
PubMed1988

The incidence of cancer following total hip replacement.

We have studied the incidence of tumours at remote sites following total hip replacement: 1,358 individuals have been followed up for 14,286 person-years after operation. In the decade following implantation the incidence of tumours of the lymphatic and haemopoietic systems was significantly greater, and that of cancer of the breast, colon, and rectum, significantly less than expected. Whilst the association might be due in part to an effect of the prosthetic implants, other mechanisms, particularly drug therapy, require consideration.

Breast Neoplasms↗
PubMed1987

Influence of spinal and general anaesthesia on haemostasis during total hip arthroplasty.

One hundred and one patients with osteoarthritis were randomly allocated to undergo total hip arthroplasty under either spinal (subarachnoid) or general anaesthesia. Venous blood was sampled before, during and after surgery and on the 5th day after operation to study the haemostatic mechanism. There were no preoperative differences between the two anaesthetic groups. Although there was pronounced individual variability, similar patterns of change in coagulation, platelets and fibrinolysis were seen in both groups. However, there were significant differences between the two groups in platelet count, thrombin production, and Factor VIIIRAg in the intra- and immediate postoperative periods. Also, compared with general anaesthesia, there was less intraoperative activation of fibrinolysis, as measured by the euglobulin clot lysis time, with spinal anaesthesia. These differences suggest slight modification of the haemostatic response to surgery with spinal anaesthesia, which could be consistent with a neuroendocrine mechanism. By the 5th day both groups exhibited a very similar "hypercoagulable" postoperative state.

Aged↗
PubMed1987

Metabolic response to total hip arthroplasty under hypobaric subarachnoid or general anaesthesia.

Whole blood glucose concentration was estimated in 93 patients undergoing total hip arthroplasty under either subarachnoid or general anaesthesia. In 77, plasma cortisol concentration was also estimated before and after surgery. There were no preoperative differences between the two groups. Blood glucose concentration increased slightly following induction in both groups, but with spinal anaesthesia it decreased again, whereas with general anaesthesia it continued to increase (P less than 0.0001). Plasma cortisol concentration with spinal anaesthesia was 291 (SD 145) nmol litre-1 before, and 279 (253) nmol litre-1 30 min after operation. With general anaesthesia there was a three-fold increase from 301 (159) nmol litre-1 (preoperative) to 987 (474) nmol litre-1 30 min after operation (P less than 0.0001). Low spinal anaesthesia with a predominantly unilateral block appears sufficient to suppress the neuroendocrine response to hip surgery.

Aged↗
PubMed1987

Skeletal tuberculosis in New Zealand since the introduction of chemotherapy.

The incidence of skeletal tuberculosis in New Zealand as measured by both hospital morbidity and notification data has fallen since the introduction of chemotherapy to low levels comparable with other developed societies. The decline has been greatest in the 5-14 year age group and least in the over 65 group. Individual surgeons can now expect to see few cases in a practising lifetime. Effective chemotherapy is the key to successful treatment. Adequate biopsy is essential, but apart from the drainage of large abscesses the place of surgery in the early management of osteoarticular tuberculosis is discretionary. Early activity can usually be encouraged once chemotherapy is instituted, late reconstruction by joint arthroplasty being available if adequate function is not achieved.

Adolescent↗
PubMed1987

Aspects of the microbe: host relationship in staphylococcal hematogenous osteomyelitis.

Nasal carriage of staphylococci, and some in vitro tests of host antimicrobial defense were studied in a group of children who had recovered from staphylococcal hematogenous osteomyelitis at least one year previously. The same studies were carried out in a group of first degree relatives, and in age- and sex-matched controls. Nasal carriage was significantly more common (P = .039) in these children than in age- and sex-matched controls, and commoner (P = .19) in the first degree relatives than in controls. Total immunoglobulin G (IgG) levels were significantly lower in the children studied than in controls (P = .022), and in relatives than in controls (P = .032), but the levels remained within an accepted normal range. IgG levels were also significantly lower in carriers of Staphylococcus aureus than in non carriers (P = .033). Other immunoglobulin levels, complement levels, leukocyte phagocytic and killing power, leukocyte chemotaxis, and leukocyte migration inhibition, were indistinguishable between the children, their relatives, and controls. No statistically significant association between histocompatibility antigen profile and previous history of osteomyelitis, or nasal carriage of staphylococci, was found. More detailed studies are required to confirm and clarify the associations.

Cell Migration Inhibition↗
PubMed1986

An orthopaedic geriatric rehabilitation unit: the first two years experience.

Experience of the first two years of an orthopaedic geriatric rehabilitation unit is described. There were 325 admissions comprising 271 females and 54 males. The predominant diagnosis was fracture of the proximal femur. Average length of stay in the unit was 43 days for males and 36.7 days for females. 75.9% of patients admitted from home returned there and 66.1% of patients admitted from residential care returned to similar accommodation. In the first year there was a fall of 13.5 days in the average length of stay for elderly females with proximal femoral fracture, resulting in 2175 less bed days for this diagnosis. This improvement has continued.

Aged↗