The effect of type of femoral component fixation on mortality and morbidity after hip hemiarthroplasty:A systematic review and meta-analysis

Background: Hip hemiarthroplasty is a well-established treatment of displaced femoral neck fracture, although debate exists over whether cemented or uncemented fixation is superior. Uncemented prostheses have typically been used in younger, healthier patients and cemented prostheses in older patients with less-stable bone. Also, earlier research has suggested that bone cement has cytotoxic effects and may trigger cardiovascular and respiratory adverse events. Questions/Purposes: The aim of this systematic review and meta-analysis was to compare morbidity and mortality rates after cemented and uncemented hemiarthroplasty for the treatment of displaced femoral neck fractures in elderly patients. Methods: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched seven medical databases for randomized clinical trials and observational studies. We compared cemented and uncemented hemiarthroplasty using the Harris Hip Score (HHS), as well as measures of postoperative pain, mortality, and complications. Data were extracted and pooled as risk ratios or standardized mean difference with their corresponding 95% confidence intervals in a meta-analysis model. Results: The meta-analysis included 34 studies (12 randomized trials and 22 observational studies), with a total of 42,411 patients. In the pooled estimate, cemented hemiarthroplasty was associated with less risk of postoperative pain than uncemented hemiarthroplasty. There were no significant differences between groups regarding HHS or rates of postoperative mortality, pulmonary embolism, cardiac arrest, myocardial infarction, acute cardiac arrhythmia, or deep venous thrombosis. Conclusions: While we found that cemented hemiarthroplasty results in less postoperative pain than uncemented hemiarthroplasty in older patients with femoral neck fracture, the lack of significant differences in functional hip scores, mortality, and complications was surprising. Further high-level research is needed

Use of Amended Tailings as Mine Waste Cover

The present study addresses the effectiveness of green liquor dregs (GLD, a residue from paper pulp-making) as a paste additive with different proportions in tailings for stabilizing mine waste by testing of uniaxial compressive strength and hydraulic conductivity. Selected samples were also investigated for freeze–thaw effect on hydraulic conductivity, and the water retention capacity was discussed based on previous results. Fly ash was also added to the paste to study the auxiliary functions such as solidification in the sealing material. GLD have the potential for use as a barrier layer material for stabilizing mine tailings by decreasing water percolation and improving water retention properties. However, the solidified paste of GLD-amended tailings possesses low uniaxial compressive strength, but the addition of fly ash to the paste increased the uniaxial compressive strength by up to 2–3 times 1 month after it was solidified, with a further two- to threefold strength increase after 3-months curing time. Although the hydraulic conductivity of the tailings paste decreased as a consequence of mixing with both GLD and FA, the difference was within one order of magnitude. The hydraulic conductivity was also reduced as the water/solid ratio of pure GLD decreased. The climatic freeze–thaw cyclic process led to 20 % increase in hydraulic conductivity. A proportion of 7:2:1 for tailings:GLD:FA was found to be a geotechnical satisfactory recipe to seal the mine waste. If porosity is reduced, improved water retention capacity and no cracking in the tailings can be assured, oxygen diffusion is limited, and oxidation of the mine waste is decelerated, thus mitigating acid rock drainage.</p