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C J Bulstrode

Publications and source records attributed to C J Bulstrode.

At least 19 recordsLinked to original sources
PubMed1997

Pain levels after total hip replacement: their use as endpoints for survival analysis.

We have assessed the relative value of various outcome measures after THR, by the analysis of follow-up data from over 2000 patients. They had been reviewed clinically and radiologically six months after operation, at one year, and then every two years, some for 16 years. At each review their pain level, stiffness and opinion of progress were scored and a radiograph taken. We found that pain level was the most informative outcome as a predictor of revision and correlated well with the patients' opinions. We made a comparison between the six types of implant in the series, using survival analysis and log-rank testing with different pain levels as endpoints. This analysis revealed differences which were not detected by survival analysis using the traditional endpoint of revision. We therefore recommend the use of different levels of pain as the main outcome measures after total hip replacement.

Adolescent↗
PubMed1997

Loss to follow-up matters.

Survival analysis of joint replacement relies on the assumption that surgical procedures in patients lost to follow-up have the same chance of failing as those in patients who continue to be assessed. Our study questions that assumption. During the 16-year follow-up of 2268 patients who had received total hip replacements 142 (6%) were lost to follow-up. The cumulative loss at 15 years was 20%. At their last assessment, patients who subsequently failed to attend for follow-up had significantly worse pain, range of movement and opinion of their progress (p < 0.001) and significantly worse radiological features than a matched control group (p < 0.01). Patients lost to follow-up have a worse outcome than those who continue to be assessed. Consequently, a survival analysis that does not take into account such patients is likely to give falsely optimistic results. It is therefore essential that vigorous attempts are made to minimise loss to follow-up, and that the rate of such loss is quoted. The overall loss to follow-up disguises the magnitude of the problem, which is best quantified by a cumulative rate of follow-up. The reliability of a study can be assessed by a loss-to-follow-up quotient, calculated by the number of failures: the lower the quotient the more reliable the data. Ideally, the quotient should be less than 1.

Aged↗
PubMed1996

The development of adolescent idiopathic scoliosis.

There are many conflicting actiological theories for adolescent idiopathic scoliosis. We present a simple new model of scoliosis and a mechanism by which it is initiated and progresses. This mechanism provides a final common pathway for the multiple aetiological factors. A simple model of the spine, incorporating its fundamental mechanical features, was constructed. The model consisted of interconnected anterior compression and posterior tension columns. It allowed normal spinal movements, with flexion limited by the posterior column and rotation centered around the anterior column. It also allowed deformities to develop. The ends of the model were fixed in the position of the vertebrae they represented. Overgrowth of the anterior column relative to the posterior column caused the model to take up the shape of an idiopathic scoliosis. The greater the overgrowth, the more marked the deformity. Normally anterior and posterior column growth are coupled. During the growth spurt the thoracic kyphosis flattens indicating that anterior growth temporarily exceeds posterior growth. If this over-growth is marked a scoliosis will develop, as demonstrated by the model. Once this occurs the coupling is lost, anterior growth further outstrips posterior growth and the deformity progresses. Not all scolioses worsen, as the tendency to progress is balanced by neuromuscular factors and remodelling. Factors that increase the growth rate, induce asymmetry or decrease the inherent stability of the spine all encourage the development and progression of a scoliosis. This explains the complex biomechanics of scoliosis and provides a final common pathway by which the multiple aetiological factors can induce idiopathic scoliosis. It has important implications for the understanding and treatment of this condition.

Adolescent↗
PubMed1996

The total cost of hip-joint replacement; a model for purchasers.

A computer-based model is used to investigate the total cost of primary total hip-joint replacement. The model takes into account the probability of prosthesis failure, death and re-revision. The results emphasize the importance of age at insertion, demonstrating that the expected life-span of the patient has a major influence on the total cost for a given prosthesis. The discussion considers the idea of a 'lifetime care package' to encapsulate the concept of quality when considering the purchasing of total hip replacements. If it is assumed that a primary replacement episode costs 3500 pounds and revision surgery costs twice as much, then the additional premium on the best implant currently available would be 630 pounds. The premium payable on the same patient using the worst design would be 3080 pounds. This difference reflects the importance of quality in total hip replacement surgery.

Adult↗
PubMed1996

Thromboprophylaxis and death after total hip replacement.

The recommendation that patients having a total hip replacement should receive pharmacological thromboprophylaxis is based on the belief that fatal pulmonary embolism is common, and that prophylaxis will decrease the death rate. To investigate these assumptions we performed a meta-analysis of all studies on hip replacement which included information about death or fatal pulmonary embolism. A total of 130 000 patients was included. The studies were so varied in content and quality that the results of our analysis must be interpreted with some caution. The fatal pulmonary embolism rate was 0.1% to 0.2% even in patients who received no prophylaxis. This is an order of magnitude lower than that which is generally quoted, and therefore the potential benefit of prophylaxis is small and may not justify the risks. To balance the risks and benefits we must consider the overall death rate. This was 0.3% to 0.4%, and neither heparin nor any other prophylactic agent caused a significant decrease. Our study demonstrates that there is not enough evidence in the literature to conclude that any form of pharmacological thromboprophylaxis decreases the death rate after total hip replacement. For this reason guidelines which recommend their routine use to prevent death after hip replacement are not justified.

Hip Prosthesis↗
PubMed1996

Migration of cemented femoral components after THR. Roentgen stereophotogrammetric analysis.

We studied the migration of 58 cemented Hinek femoral components for total hip replacement, using roentgen stereophotogrammetric analysis over four years. The implants migrated faster during the first year than subsequently, and the pattern of migration in the second period was very different. During the first year they subsided, tilted into varus and internally rotated. After this there was slow distal migration with no change in orientation. None of the prostheses has yet failed. The early migration is probably caused by resorption of bone damaged by surgical trauma or the heat generated by the polymerisation of bone cement. Later migration may be due to creep in the bone cement or the surrounding fibrous membrane. The prosthesis which we studied allows the preservation of some of the femoral neck, and comparison with published migration studies of the Charnley stem suggests that this decreases rotation and may help to prevent loosening.

Adult↗
PubMed1996

Long-term comparison of Charnley and Stanmore design total hip replacements.

We reviewed the records of the long-term outcome of 208 Charnley and 982 Stanmore total hip replacements (THR) performed by or under the supervision of one surgeon from 1973 to 1987. The Stanmore implant had a better survival rate before revision at 14 years (86% to 79%, p = 0.004), but the difference only became apparent at ten years. The later Stanmore implants did better than the early ones (97% to 92% at ten years, p = 0.005), the improvement coinciding with the introduction of a new cementing technique using a gun. Most of the Charnley implants were done before most of the Stanmore implants so that the difference between the results may in part be explained by improved methods, but this is not the complete explanation since a difference persisted for implants carried out during the same period of time. We conclude that improved techniques have reduced failure rates substantially. This improvement was much greater than that observed between these two designs of implant. Proof of the difference would require a very large randomised controlled trial over a ten-year period.

Bone Cements↗
PubMed1995

Workload in trauma and orthopaedic surgery: use of linked statistics to profile a specialty.

We have used linked hospital morbidity statistics to construct a basic profile of the demographic and epidemiological features of trauma and orthopaedic surgery in a defined population. This paper reports on this profile and illustrates trends in the specialty between 1976-86. During this period episode-based inpatient admission rates rose by about 20%. Multiple admissions per person varied with age but did not increase over time. Thus the increase in admission rates in this specialty represented an increase in numbers of people who received treatment. Average length of stay per episode of inpatient care and the total time spent in hospital per person declined over time. New outpatient attendance rates increased by 19% in the 11-year period. The ratio of follow-up outpatient appointments to new appointments fell from 2.68:1 to 2.24:1; the number of inpatient beds fell by about 13% and bed occupancy remained stable at about 80%. We describe some of the major components of clinical workload in the specialty, with emphasis on conditions for which admission rates changed over time, relating the data to numbers of people treated as well as to episodes of care.

Adolescent↗
PubMed1995

Roentgen stereophotogrammetric analysis for assessing migration of total hip replacement femoral components.

A new Roentgen stereophotogrammetric analysis system, using a biplane technique, has been developed to determine the migration and rotation of total hip replacement (THR) femoral components in three dimensions. Stainless steel marker balls were injected into the femur during the operation. The patients stood within a calibration frame during the X-ray. The two exposures were taken consecutively allowing radio-opaque shutters to be moved in front of the films to prevent fogging. Studies with a model demonstrated that the system was capable of measuring the position of an implant to better than 0.11 mm (2 SD). In vivo measurements demonstrated that the migration rate of the different parts of the femoral component could be determined with an accuracy of 0.25 to 0.50 mm/year. By considering the accuracy determined in different ways, methods for improving the system have been identified. The migration and rotation rate of 58 Hinek cemented femoral components was studied for four years. Migration was three to five times greater (p < 0.001) during the first year than subsequently. The prosthesis head moved the most during the first year (0.94 mm). A better understanding of the cause of implant failure could be obtained by studying the early migration of different types of prosthesis and comparing this with their clinical results and design features.

Algorithms↗
PubMed1995

Which primary total hip replacement?

To assist surgeons to select a total hip replacement (THR) we present comparative information on all such implants on the market in the UK. We identified 62 different primary THRs, manufactured by 19 companies; half had been introduced in the last five years, and only 30% have any results published in peer-reviewed journals. The prices range from 250 pounds to 2000 pounds, and the two cheapest implants have the longest reported follow-up. The number of THR implants available in the UK, and presumably the rest of the world, is rapidly increasing, but there is little or no scientific evidence that the newer, more expensive, implants are better than established designs. Some will undoubtedly be worse. We believe that this situation is unsatisfactory and make recommendations for improvement, in particular that preference be given to implants with good results in published peer-reviewed long-term clinical trials.

Evaluation Studies as Topic↗
PubMed1993

Designer hips.

Explore the source record for details and available documents.

Budgets↗
PubMed1992

Bone resorption by cells isolated from rheumatoid synovium.

Cellular mechanisms accounting for the osteolysis of rheumatoid erosions are poorly understood. Cells were isolated and characterised from the synovium of 16 patients with rheumatoid arthritis (RA) and four patients with osteoarthritis and their ability to resorb bone was assessed using a scanning electron microscope bone resorption assay. Macrophages were the major cell type isolated from the synovium of patients with RA. These produced extensive roughening of the bone surface without resorption pit formation. This low grade type of bone resorption was not affected by systemic (calcitonin, parathyroid hormone, 1,25-dihydroxyvitamin D3) or local (interleukin 1, prostaglandin E2) factors influencing bone resorption. Macrophage mediated bone resorption differs qualitatively and quantitatively from that of osteoclasts but is likely to play an important part in the development of marginal erosions in RA.

Adult↗
PubMed1992

Resorption of bone by inflammatory cells derived from the joint capsule of hip arthroplasties.

The role of inflammatory cells in aseptic loosening and failure of cemented joint replacements is unclear. Inflammatory cells from the revision joint capsule of four failed hip arthroplasties were examined to determine their nature and resorptive capacity. The capsules contained numerous macrophages and abundant foreign-body macrophage polykaryons, distinguished from osteoclasts by their antigenic phenotype and lack of response to calcitonin. When cultured on cortical bone slices in vitro, both macrophages and macrophage polykaryons produced small resorption pits and were associated with areas of superficial resorption of the bone surface. These results indicate that foreign-body induced macrophages and macrophage polykaryons are capable of a type of low-grade bone resorption which may be of pathogenic significance in the loosening of cemented joint prosthetic components.

Antibodies, Monoclonal↗