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- Aspenberg, Per, 1949-, et al.
(författare)
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Fixed or loose? Dichotomy in RSA data for cemented cups
- 2008
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Ingår i: Acta Orthopaedica. - Basingstoke : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 79:4, s. 467-473
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Roentgen stereometric analysis (RSA) cannot discern whether a single prosthesis is fixed or migrating below the detection level. Samples of patients usually show migration values that appear to be continuously distributed. Is there such continuity, or is there a dichotomy between stable and migrating prostheses? The hypothesis of a dichotomy has, to our knowledge, not been tested. We present an exploratory evaluation of such a dichotomy using a mixture distribution algorithm. METHODS: We analyzed the migration (as determined by RSA) of 147 cemented acetabular cups of 7 different designs by using a new set of algorithms for frequency distribution analysis called Rmix. RESULTS: We first analyzed a migration vector, regardless of direction. After 2 years there was a significant dichotomy between 2 lognormal subgroups within the sample. Although some types of cups were over-represented in one of the subgroups, neither cup design, sex, nor operating department could explain the dichotomy into two groups, which appears to reflect the existence of two basically different types of behavior of the cups. We next analyzed the migration along the 3 axes in space, and found a similar dichotomy. During the second year, around 80% of the patients belonged to a distinct, normally distributed subgroup with a mean not different from 0 mm and a small variation. The remainder differed significantly from this subgroup and showed migration. INTERPRETATION: There is a dichotomy in migration pattern. During the second postoperative year, most cups belonged to a subpopulation that appeared stable. The remainder is probably at risk of loosening. For a single type of prosthesis, the relative size of the stable subgroup may be a good index of the expected performance. The possibility of detecting subgroups within a seemingly continuous sample might be useful in many fields of medicine.
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| 2. |
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| 3. |
- Wagner, Philippe, et al.
(författare)
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Increased cancer risks among arthroplasty patients: 30year follow-up of the Swedish Knee Arthroplasty Register.
- 2011
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Ingår i: European Journal of Cancer. - : Elsevier BV. - 1879-0852 .- 0959-8049. ; 47:7, s. 1061-1071
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: An increasing number of young patients are undergoing knee arthroplasties. Thus, the long-term risks of having a knee prosthesis must be evaluated. This study focuses on the potential carcinogenic effects of the prosthesis; it is a long-term follow-up of all patients in Sweden between 1975 and 2006. METHODS: The incidence of cancer in a total population of operated individuals was compared to the overall national cancer incidence in Sweden by means of standardised incidence ratios. Analysis of cancer latency period was performed to identify potential aetiological factors. RESULTS: For male and female patients with rheumatoid arthritis (RA) or osteoarthritis (OA), the overall cancer risks were elevated, ranging from 1.10 (95% confidence interval (CI): 1.03-1.18) for men with OA to 1.26 (1.23-1.29) for men with RA. The greatest increases in risk were observed for the leukaemia subtypes, myelodysplastic syndromes (MDS) and essential thrombocytosis (ET), ranging from 3.31 (1.24-8.83) for ET in men with OA to 7.38 (1.85-29.51) for ET in women with RA. Increases in risk were also observed for breast cancer, prostate cancer and melanoma. The latency analysis revealed elevated risks late in the study period for both solid and haematopoietic cancers. However, only increases in MDS and possibly prostate cancer and melanoma rates appeared to be connected to the operation. CONCLUSION: This study showed that OA and RA arthroplasty patients have a significantly higher risk of cancer than the general population. Elevated risks of MDS and possibly prostate cancer and melanoma indicated a potential connection to exposure to metals in the implant. The observed excessive incidence of ET was likely associated with the inflammatory disease.
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| 4. |
- Wagner, Philippe, et al.
(författare)
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Metal-on-metal joint bearings and hematopoetic malignancy A review
- 2012
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3682 .- 1745-3674. ; 83:6, s. 553-558
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Forskningsöversikt (refereegranskat)abstract
- This is a review of the hip arthroplasty era. We concentrate on new metal bearings, surface replacements, and the lessons not learned, and we highlight recent reports on malignancies and joint implants. A low incidence of blood malignancies has been found in bone marrow taken at prosthetic surgery. The incidence is increased after replacement with knee implants that release very low systemic levels of metal ions. A carcinogenic effect of the high levels of metal ions released by large metal-on-metal implants cannot be excluded. Ongoing Swedish implant registry studies going back to 1975 can serve as a basis for evaluation of this risk.
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| 5. |
- Wagner, Philippe, et al.
(författare)
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Oral contraceptive use, parity, and constitutional characteristics in soft tissue sarcoma : a Swedish population-based case-control study 1988-2009
- 2014
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Ingår i: Cancer Causes and Control. - : Springer Science and Business Media LLC. - 0957-5243 .- 1573-7225. ; 25:9, s. 1167-1177
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The study was designed to investigate the influence of surrogate factors associated with sex (SH) and growth hormones (GH) on the risk of developing soft tissue sarcomas (STS).BACKGROUND AND METHODS: The etiology of soft tissue sarcoma is largely unknown. We have studied the effect of hormone related factors on STS in the Swedish population between 1988 and 2009 using a population-based matched case-control design.RESULTS: Our study is the largest on this topic to date, including 634 cases in a primary matched analysis and 855 cases in an unmatched sensitivity analysis. We identified protective effects connected to constitutional characteristics, hormonal and reproductive factors. Being shorter than your peers at age 11 was associated with an odds ratio (OR) of 0.51 (0.36-0.74). Having used oral contraceptives (OC), OR 0.75 (0.49-1.15), and high parity, OR 0.16 (0.04-0.63), comparing three or more children to two or less, also appeared to reduce the risk of STS. The risk was further reduced with the duration of OC use (p = 0.01), comparing use for 11 years or more to use for 3 years or less yielded an OR of 0.10 (0.02-0.41). No effect was observed for ever having had perimenopausal hormone therapy OR 1.02 (0.70-1.47). The effect of BMI varied significantly with subtype (p = 0.03) and tumor location (p < 0.001).CONCLUSIONS: We observed surrogates of SH, GH, and insulin-like growth factor 1 to be associated with STS development. These findings are important as they may connect STSs to the group of hormone-dependent tumors, potentially revealing common treatment and prevention targets.
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