Early mortality after elective hip surgery.
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Biomedical subjects
Publications and source records attributed to Stein Atle Lie.
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INTRODUCTION: The cementation of a total hip prosthesis may cause bone necrosis, either by direct toxicity or by generation of heat during the polymerization process. This necrotic bone may create conditions that encourage the growth of bacteria. We compared the revision rates due to infection in primary uncemented total hip arthroplasties (THAs) with those of cemented THAs with antibiotic-loaded cement and to those of cemented THAs without antibiotic cement. METHODS: Data from the Norwegian Arthroplasty Register for the period 1987-2003 were used. To have comparable groups, we analyzed only primary THAs performed because of primary osteoarthrosis, and where both the acetabular and the femoral component of the prosthesis were either uncemented or cemented (n = 56,275). RESULTS: In total, 252 revisions due to infection were reported. Compared to the uncemented THAs (n = 5,259), the risk of revision due to infection for THAs without antibiotic cement (n = 15,802) was increased 1.8 times (CI 1.0-3.1; p = 0.04). No differences could be detected when compared to THAs with antibiotic-loaded cement (n = 35,214) (RR 1.2, CI 0.7-2.0; p = 0.5). The average operating time for uncemented THAs was 15 min less than for cemented THAs. INTERPRETATION: The risk of revision due to infection was the same for uncemented and for cemented arthroplasties with antibiotic-loaded cement, but higher for cemented arthroplasties without antibiotic cement. Our findings can be explained by reduced resistance to infection caused by the cement, which appears to be neutralized by adding antibiotic to the cement.
BACKGROUND: Brain imaging studies have revealed anatomical anomalies in the brains of individuals with Tourette syndrome (TS). Prefrontal regions have been found to be larger and the corpus callosum (CC) area smaller in children and young adults with TS compared with healthy control subjects, and these anatomical features have been understood to reflect neural plasticity that helps to attenuate the severity of tics. METHOD: CC white matter connectivity, as measured by the Fractional Anisotropy (FA) index from diffusion tensor images, was assessed in 20 clinically well-defined boys with Tourette syndrome and 20 age- and gender-matched controls. RESULTS: The hypothesis that children with TS would show reduced measures of connectivity in CC fibers was confirmed for all subregions of the CC. There was no significant interaction of TS and region. Reductions in FA in CC regions may reflect either fewer interhemispheric fibers or reduced axonal myelination. FA values did not correlate significantly with the severity of tic symptoms. Group differences in measures of connectivity did not seem to be attributable to the presence of comorbid ADHD or OCD, to medication exposure, or group differences in IQ. CONCLUSION: Our findings of a reduced interhemispheral white matter connectivity add to the understanding of neural connectivity and plasticity in the brains of children who have TS.
4-N,N-Dimethyl amino benzoic acid ethylester (DMABEE), a leachable lipophilic component of polymer-based dental-filling materials, has been shown to interact with cell membrane phospholipids, such as phosphatidylcholine and phosphatidylserine (PS). One marker of cellular death by apoptosis is the change in architecture of the plasma membrane involving the translocation of the negatively charged PS from the inner to the outer leaflet of the cell membrane. We therefore hypothesized that DMABEE has the potential to induce apoptosis. The necrosis inducing potential was also investigated. To test our hypothesis human monoblastoid U-937 cells were exposed to 10, 20, 40, 80, 120, 160, and 200 microM of DMABEE for 24, 48, and 72 h. At the culture end-points apoptotic and necrotic cells were detected by flow cytometry. DMABEE enhanced cell death by apoptosis and necrosis in U-937 cells in a dose-dependent fashion. The data support our hypothesis that DMABEE triggers death-signaling pathways.
Artificial hip joints are used in only one hip for about 85 per cent of the patients and in both hips (bilateral) for about 15 per cent of the patients. The occurrence of bilateral prostheses and the influence they have in survival analyses of joint arthroplasties are seldom considered. In this study we therefore focus on issues related to bilateral primary hip prostheses, time to revision surgery, and some commonly used statistical methods. We used information from 47,355 patients with 55,782 primary hip prostheses reported to the Norwegian Arthroplasty Register between 1987 and 2000. Due to the large number of diagnoses, fixation techniques for the prostheses, and combination of prostheses brands, we furthermore considered a 'homogeneous' subset of 8703 prostheses from 7930 patients with primary osteoarthritis, and Charnley prosthesis fixed with antibiotic-containing Palacos cement. Kaplan-Meier curves for all prostheses, ignoring that some patients have bilateral prostheses, were compared with Kaplan-Meier curves using only the first inserted prostheses, and with survival curves modified for patients with bilateral prostheses. Cox regression analyses were used to assess explanatory variables and to adjust for confounding factors. The results from the ordinary Cox regression analyses were compared with results from a marginal model, a shared gamma frailty model, and a model using a time dependent covariate to condition on failures in the opposite hip. We found no practical difference between the three calculated survival curves for the hip replacement data. The ordinary Cox-model and the marginal model gave equivalent results. In the shared gamma frailty model estimates for the risk factors were comparable with the former two approaches. The estimated frailty variance was higher when all data were used, even after adjustment for confounding factors. For the 'homogeneous' data the estimated frailty variance was negligible. Using a time dependent covariate to condition on previous revisions in the opposite hip, we found a higher risk of revision for the remaining primary hip prosthesis if the opposite hip had been revised (RR = 3.49, p < 0.0001). There was no difference in risk for revision between right and left hip prostheses. If the time interval between the two primary operations was more than two years, for the full data, the first hip prosthesis had an increased risk of revision compared to prostheses in patients with only one prosthesis (RR = 1.25, p = 0.01). For the 'homogeneous' data no statistically significant difference was found between unilateral and bilateral prostheses. A revision in one hip, for patients with bilateral prostheses, is a risk factor for revision of the other hip. Thus, in analyses of prostheses survival, dependencies between two hip prostheses from one patient should be considered. However, ignoring possible dependencies does not necessarily have an impact on the results on standard risk factors.
OBJECTIVE: To compare the mortality of a community-based cohort of patients with carefully diagnosed Parkinson disease (PD) with the mortality in an age-matched population from the same study area and to investigate the possible influence of clinical features and diagnostic accuracy on survival in PD. METHODS: A total of 245 patients with PD were identified and included in the study. Patients were classified into groups of clinical definite, probable, and possible PD. The study period was 8 years. A total of 142 patients died. The mortality rates for the Norwegian population, which were available in 1-year intervals for all birth cohorts and both sexes during the study period, were used as controls. RESULTS: The standardized mortality ratio (SMR) for the total patient group was 1.52. The mortality rate was increased for both sexes (male SMR = 1.54, female SMR = 1.49) and in all age groups at disease onset (<60 years SMR = 1.92, 60 to 70 years SMR = 1.50, >70 years SMR = 1.41). The survival of patients with clinical definite PD was only modestly reduced (SMR = 1.35), whereas the SMR for possible PD was as high as 1.99. CONCLUSIONS: Our study gives evidence for increased mortality in PD despite modern treatment. The increase is not extensive in patients with a high probability for idiopathic PD.
AIM OF STUDY: The objective of this study was to determine the pattern of recurrence after one or more episodes of adhesive small bowel obstruction (ASBO) during a follow-up period of up to 40 years. Furthermore, we wanted to analyze possible factors with an influence on the recurrence rate and to study the magnitude of "everyday" abdominal pain among these patients. PATIENTS AND METHODS: Hospital records of 500 patients operated on for adhesive obstruction at Haukeland University Hospital from 1961 to 1995 were studied. The patients were followed until death, loss to follow-up, or end of study (February 2002), with a median follow-up of 10 years and a maximum follow-up time of 40 years. A questionnaire was sent to all living patients to obtain information on recurrences and abdominal complaints. RESULTS: The cumulative recurrence rate for patients operated once for ASBO was 18% after 10 years and 29% at 30 years. For patients admitted several times for ASBO, the relative risk of recurrent ASBO increased with increasing number of prior ASBO episodes. The cumulative recurrence rate reached 81% for patients with 4 or more ASBO admissions. Other factors influencing the recurrence rate were the method of treatment of the last previous ASBO episode (conservative versus surgical) and the number of abdominal operations prior to the initial ASBO operation. Compared to results from the general populations, more ASBO patients suffer from abdominal pain at home. Women and patients having matted adhesions have significantly more complaints about abdominal pain than men and patients with band adhesions. CONCLUSION: The risk of recurrence increased with increasing number of ASBO episodes. Most recurrent ASBO episodes occur within 5 years after the previous one, but a considerable risk is still present 10 to 20 years after an ASBO episode. Surgical treatment decreased the risk of future admissions for ASBO, but the risk of new surgically treated ASBO episodes was the same regardless of the method of treatment. People treated for ASBO seem to be more prone to experiencing abdominal pain than the normal population, especially those having matted adhesions.
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We studied the effects of antibiotic prophylaxis, systemically and in bone cement, on the revision rate of cemented total hip arthroplasties (THAs) in data from the Norwegian Arthroplasty Register during the period 1987-2001. To have comparable groups, only THAs performed because of primary osteoarthritis, using cemented implants with documented good results, and high-viscosity cement were included. If systemic antibiotic prophylaxis had been given, only operations with cephalosporin or penicillin were selected. Cox-estimated survival relative revision risks (RR) are presented with adjustment for differences among groups in gender, age, cement brand, type of systemic antibiotic prophylaxis, type of prosthesis, type of operating room, and duration of the operation. Of 22,170 THAs studied, 696 THAs (3.1%) were revised, 440 (2.0%) for aseptic loosening and 102 (0.5%) for deep infection. We found the lowest risk of revision when the antibiotic prophylaxis was given both systemically and in the cement (15,676 THAs). Compared to this combined regime, patients who received antibiotic prophylaxis only systemically (5,960 THAs) had a 1.4 times higher revision rate with all reasons for revision as endpoint (p = 0.001), 1.3 times higher with aseptic loosening (p = 0.02) and 1.8 times higher with infection as the endpoint (p = 0.01). With the combined antibiotic regime, the results were better if antibiotics were given 4 times on the day of surgery (2,194 THAs), as compared to once (1,424 THAs) (p < 0.001), twice (2,680 THAs) (p < 0.001), or 3 times (5,522 THAs) (p = 0.02). Those who received systemic prophylaxis a single day 1, 2 or 3 times, as compared to 4 times, had a revision rate 1.8-3.5 times higher with all reasons for revision as endpoint, 1.5-3.1 times higher with aseptic loosening, and 2.7-6.8 times higher with infection. When we compared systemic prophylaxis 4 times in 1 day, no further improvement resulted in those given systemic prophylaxis for 2 days (1,928 THAs) or 3 days (717 THAs). In a subset of data including only the Charnley prosthesis, we obtained similar results. This observational study shows that the best results were recorded when antibiotic prophylaxis was given both systemically and in the bone cement, and if the systemic antibiotic was given 4 times on the day of surgery.
Patients in the Norwegian Arthroplasty Register with a total hip replacement (THR) have a lower long-term mortality than the age- and gender-matched Norwegian population. We analyzed the early postoperative mortality after 67,548 THR operations in 68 hospitals reported to the Norwegian Arthroplasty Register between 1987 and 1999. Data on deaths and causes of death were obtained from from Statistics Norway, and on thromboprophylaxis from a separate questionnaire sent to all hospitals. During the years 1987-2000 the 68 hospitals reported use of 6 thromboprophylaxis drugs and 24 different combinations of drugs and stockings. In 1988, only 3 of 29 hospitals reported use of low molecular weight heparin (LMWH), but in 1999, 67 of the 68 hospitals used LMWH. In the first postoperative week, the daily mortality was about 2.5 deaths per 10,000 THR patients. By the 70th postoperative day, the daily mortality had declined to about 0.57 deaths per 10,000 patients. The daily mortality of the age- and gender-matched Norwegian population was 0.95 deaths per 10,000 individuals. Early postoperative mortality increased with age, was higher in men than women, and was usually due to vascular disease. We found only a slight reduction in the 60-day postoperative mortality during the period 1987-1999. All underlying diagnoses for a prosthesis operation had a higher 60-day postoperative mortality than primary osteoarthrosis.
We studied primary total knee replacements (TKRs), reported to the Norwegian Arthroplasty Register, operated on between 1994 and 2000. A Cox multiple regression model was used to evaluate differences in survival among the prosthesis brands, their types of fixation, and whether or not the patella was resurfaced. In Norway in 1999, the incidence of knee prosthesis operations was 35 per 100,000 inhabitants. Cement was used as fixation in 87% of the knees, 10% were hybrid and 2% uncemented implants. Bicompartmental (not resurfaced patella) prostheses were used in 65% of the knees. With all revisions as endpoint, no statistically significant differences in the 5-year survival were found among the cemented tricompartmental prostheses brands: AGC 97% (n 279), Duracon 99% (n 101), Genesis I 95% (n 654), Kinemax 98% (n 213) and Tricon 96% (n 454). The bicompartmental LCS prostheses had a 5-year survival of 97% (n 476). The type of meniscal bearing in LCS knees had no effect on survival. Survival with revision for all causes as endpoint showed no differences among types of fixation, or bi- or tricompartmental prostheses. Pain alone was the commonest reason for revision of cemented bicompartmental prostheses. The risk of revision because of pain was 5.7 times higher (p < 0.001) in cemented bicompartmental prostheses than cemented tricompartmental ones, but the revisions mainly involved insertion of a patellar component. In tricompartmental prostheses the risk of revision because of infection was 2.5 times higher than in bicompartmental ones (p = 0.03). Young age (< 60) and the sequelae after a fracture increased the risk of revision. The 5-year survival of the 6 most used cemented tricompartmental knee prostheses brands varied between 95% and 99%, but the differences were not statistically significant. There were more revisions because of pain in bicompartmental than in tricompartmental knees. In tricompartmental knees, however, there were more revisions because of an infection. The relatively few patients with uncemented and hybrid implants showed no improvements in results compared to cemented knee prostheses.