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Biomedical subjects

Michael O'Rourke

Publications and source records attributed to Michael O'Rourke.

15 recordsLinked to original sources
PubMed2006

Differential impact of blood pressure-lowering drugs on central aortic pressure and clinical outcomes: principal results of the Conduit Artery Function Evaluation (CAFE) study.

BACKGROUND: Different blood pressure (BP)-lowering drugs could have different effects on central aortic pressures and thus cardiovascular outcome despite similar effects on brachial BP. The Conduit Artery Function Evaluation (CAFE) study, a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT), examined the impact of 2 different BP lowering-regimens (atenolol+/-thiazide-based versus amlodipine+/-perindopril-based therapy) on derived central aortic pressures and hemodynamics. METHODS AND RESULTS: The CAFE study recruited 2199 patients in 5 ASCOT centers. Radial artery applanation tonometry and pulse wave analysis were used to derive central aortic pressures and hemodynamic indexes on repeated visits for up to 4 years. Most patients received combination therapy throughout the study. Despite similar brachial systolic BPs between treatment groups (Delta0.7 mm Hg; 95% CI, -0.4 to 1.7; P=0.2), there were substantial reductions in central aortic pressures with the amlodipine regimen (central aortic systolic BP, Delta4.3 mm Hg; 95% CI, 3.3 to 5.4; P<0.0001; central aortic pulse pressure, Delta3.0 mm Hg; 95% CI, 2.1 to 3.9; P<0.0001). Cox proportional-hazards modeling showed that central pulse pressure was significantly associated with a post hoc-defined composite outcome of total cardiovascular events/procedures and development of renal impairment in the CAFE cohort (unadjusted, P<0.0001; adjusted for baseline variables, P<0.05). CONCLUSIONS: BP-lowering drugs can have substantially different effects on central aortic pressures and hemodynamics despite a similar impact on brachial BP. Moreover, central aortic pulse pressure may be a determinant of clinical outcomes, and differences in central aortic pressures may be a potential mechanism to explain the different clinical outcomes between the 2 BP treatment arms in ASCOT.

Age Distribution↗
PubMed2006

The use of structural distal femoral allografts for acetabular reconstruction. Surgical technique.

BACKGROUND: Acetabular fixation during revision total hip arthroplasty in patients who have a nonsupportive superior dome and proximal migration of the acetabular component (a Paprosky Type-IIIa defect) cannot be achieved reliably with use of a hemispherical porouscoated component alone. The purposes of the present study were to determine the long-term results associated with the use of a porous-coated hemispherical acetabular component, supported with a distal femoral structural allograft, for revision at the site of a Type-IIIa defect and to determine if graft resorption leads to late failure. METHODS: Thirty-one patients who had an acetabular reconstruction with use of a distal femoral allograft for the treatment of a Type-IIIa defect between January 1985 and December 1990 were followed annually with clinical and radiographic evaluations. At the time of the latest follow-up, eight patients had died and one patient had been lost to follow-up. One of the patients who died had had a clinical failure at 4.5 years postoperatively and was included in the analysis. Therefore, twenty-three patients, who had had an average age of sixty-one years at the time of the index procedure, were evaluated at an average of 10.3 years postoperatively. RESULTS: Five acetabular components were re-revised because of aseptic loosening at an average of 5.3 years after the index procedure. Radiographically, all but one of the remaining components were stable and showed evidence of bone ingrowth. The average Merle D'Aubigné and Postel hip score improved from 5 points preoperatively to 10 points at the time of the latest follow-up. Allograft bone resorption, although difficult to quantitate, was observed around six of the seventeen stable components and around two of the five components that failed clinically. CONCLUSIONS: Acetabular revision with use of a porous-coated acetabular component along with a structural distal femoral allograft for the treatment of a Type-IIIa defect demonstrated a high rate of clinical and radiographic success after an average of ten years of follow-up.

Acetabulum↗
PubMed2006

Impact of comorbidities on the measurement of health in patients with ankle osteoarthritis.

BACKGROUND: Investigators seeking to understand the impact of musculoskeletal disorders commonly use validated outcome instruments to assess the effect of diseases on physical function and quality of life. However, the influence of concomitant systemic or musculoskeletal comorbidities on these scores has not been widely considered in orthopaedic research. The purpose of this study was to determine how morbidity unrelated to the ankle influences the perception of physical function and pain by patients with ankle osteoarthritis. METHODS: Short Form-36 (SF-36) Physical Component Summary (PCS) and Mental Component Summary (MCS) scores, Ankle Osteoarthritis Scale (AOS) pain scale scores, demographic data, and systemic and musculoskeletal comorbidities were determined prospectively for 195 patients with ankle osteoarthritis and ninety-five age and gender-matched controls. The effect of systemic and musculoskeletal comorbidities on each of the scores was determined. RESULTS: On the average, patients with ankle osteoarthritis had a relatively normal MCS score (47 +/- 13 points) and a markedly diminished PCS score (32 +/- 8 points). Both of these scores averaged 50 +/- 9 points in the control group. The AOS pain score averaged 61 +/- 23 points in the group with ankle osteoarthritis, whereas it averaged 10 +/- 15 points in the control group. We found the perception of ankle pain by patients with ankle osteoarthritis to be significantly and linearly associated with the number of other musculoskeletal problems (not related to the foot or ankle). CONCLUSIONS: The degree of physical impairment associated with ankle osteoarthritis, as measured with the SF-36, is equivalent to that reported to be associated with severely disabling medical problems including end-stage kidney disease and congestive heart failure. The perception of ankle health status as measured with a validated, patient-oriented, anatomically specific instrument is influenced by the patients' perception of their overall musculoskeletal comorbidity status. The authors of clinical studies using these instruments should adjust for concomitant musculoskeletal disease.

Ankle Joint↗
PubMed2005

The treatment of pelvic discontinuity during acetabular revision.

Pelvic discontinuity is frequently encountered during acetabular revision in patients with severe acetabular bone loss. Prompt recognition of the discontinuity and appropriate intraoperative management are essential for a successful clinical outcome. The treatment of the discontinuity is dependent upon the remaining host bone, the potential for healing of the discontinuity, and the potential for biologic ingrowth of acetabular components. If healing potential of the discontinuity exists, the discontinuity should be treated in compression with a posterior column plate and structural allograft or with the use of trabecular metal acting as an internal plate. If healing potential for the discontinuity does not exist, the discontinuity can be bridged and treated in distraction with either an acetabular transplant supported with a cage or with the use of a custom Triflange implant. However, the poor clinical results observed with either of these treatment modalities for a type IIIB defect with an associated pelvic discontinuity have prompted the senior author to explore the use of a trabecular metal acetabular component with 1 or 2 augments in the majority of his current type IIIB cases. The long-term clinical results of this treatment remain unknown.

Acetabulum↗
PubMed2005

The treatment of acetabular bone defects with an associated pelvic discontinuity.

UNLABELLED: Pelvic discontinuity is encountered frequently during acetabular revision in patients with severe acetabular bone loss. Prompt recognition of the discontinuity and appropriate intraoperative treatment are essential for a successful clinical outcome. The treatment of the discontinuity is dependent on the remaining host bone, the potential for healing of the discontinuity, and the potential for biologic ingrowth of acetabular components. If healing potential of the discontinuity exists, the discontinuity should be treated in compression with a posterior column plate and structural allograft or with the use of trabecular metal acting as an internal plate. If healing potential for the discontinuity does not exist, the discontinuity should be bridged and treated in distraction with an acetabular transplant supported with a cage, a trabecular metal component with trabecular metal augmentation, or with the use of a custom triflange implant. LEVEL OF EVIDENCE: Therapeutic study, Level III-1 (case-control study). See the Guidelines for Authors for a complete description of levels of evidence.

Acetabulum↗
PubMed2005

The use of structural distal femoral allografts for acetabular reconstruction. Average ten-year follow-up.

BACKGROUND: Acetabular fixation during revision total hip arthroplasty in patients who have a nonsupportive superior dome and proximal migration of the acetabular component (a Paprosky Type-IIIa defect) cannot be achieved reliably with use of a hemispherical porous-coated component alone. The purposes of the present study were to determine the long-term results associated with the use of a porous-coated hemispherical acetabular component, supported with a distal femoral structural allograft, for revision at the site of a Type-IIIa defect and to determine if graft resorption leads to late failure. METHODS: Thirty-one patients who had an acetabular reconstruction with use of a distal femoral allograft for the treatment of a Type-IIIa defect between January 1985 and December 1990 were followed annually with clinical and radiographic evaluations. At the time of the latest follow-up, eight patients had died and one patient had been lost to follow-up. One of the patients who died had had a clinical failure at 4.5 years postoperatively and was included in the analysis. Therefore, twenty-three patients, who had had an average age of sixty-one years at the time of the index procedure, were evaluated at an average of 10.3 years postoperatively. RESULTS: Five acetabular components were re-revised because of aseptic loosening at an average of 5.3 years after the index procedure. Radiographically, all but one of the remaining components were stable and showed evidence of bone ingrowth. The average Merle D'Aubigné and Postel hip score improved from 5 points preoperatively to 10 points at the time of the latest follow-up. Allograft bone resorption, although difficult to quantitate, was observed around six of the seventeen stable components and around two of the five components that failed clinically. CONCLUSIONS: Acetabular revision with use of a porous-coated acetabular component along with a structural distal femoral allograft for the treatment of a Type-IIIa defect demonstrated a high rate of clinical and radiographic success after an average of ten years of follow-up.

Acetabulum↗
PubMed2003

Organisational reform in healthcare in China: impacts on the social functions of public hospitals.

Public hospital reform in China since the mid 1980s has had detrimental effects on hospitals' social functions, especially the provision of care for poor people. This study of hospitals in Northern China, using a range of economic measurements, indicated that there has been an overall decline in social functions since 1985, especially in secondary and tertiary level hospitals. Reason for this include the increasingly competitive medical market in China and, under the decentralisation reforms, the imperative for hospitals to generate revenue. We put forward policies to strengthen hospital social functions, including funding for essential packages of services to specifically benefit the poor and vulnerable, and increased government subsidies to support social functions in primary level hospitals where care can be more easily accessed.

China↗
PubMed2003

Building capacity in the Mongolian health sector: a training methodology based on identified needs assessments.

Mongolian health care is moving from a centrally planned hierarchical basis towards greater decentralisation as part of overall sector wide reform. To identify key needs of health personnel to help to build capacity, we undertook research aimed at assessing priority training areas. The research results indicated gaps and weaknesses in many technical areas, but also significant problems in terms of how Mongolian health organizations function, including rigid structures, isolated management, and little internal communication. These features militate against optimal agency effectiveness. This paper discusses how specific training programs were developed based on quantitative research and an overarching organisation improvement theme emphasizing openness; communication; and participation to maximize the benefits of skills transfer and capacity development.

Education, Continuing↗
PubMed2003

Community involvement in health in Mongolia: hospital boards and other participatory structures.

Under the Soviet central planning model that operated until 1990, the Mongolian population had little or no involvement in decision-making about health care. As part of overall health sector reform in Mongolia, hospital boards have been established, with significant community representation, to guide strategic and financial management and to assist in developing services according to community needs and expectations. We discuss experiences, and steps taken to resolve initial problems. We also describe other more recent participatory models including the family group practice initiative which involves the community choosing their doctor, community management of revolving drug finds, establishment of community health volunteer networks, and the governments information campaign strategy on the reforms. The community participation models in Mongolia are part of an ongoing process of openness and emphasise the commitment to change in that country. We argue that these experiences have the potential to guide and inform similar measures in other transitional countries.

Community Participation↗