Total knee and hip arthroplasty were the main arthroplasty surgery performed in Brazil. In Brazil, around 50% of arthroplasty surgeries are performed by the public health system, knowing as SUS 1. SUS is the biggest public and universal health system in the world, attending 100% of the Brazilian population (220 million), with 2020's expected budget of US$ 31 billion 2,3. The National Institute of Clinical Excellence utilizes the QALY system (Quality adjustment year life)to calculate the best cost-benefit between medical interventions 4. In compliance with the study, an operated person has a QALY index of £5000 while a non-operated person has an index of £7182. In March 2020, due to the COVID-19 pandemics, the Brazilian Health Ministry oriented for the postponing of elective surgery, to prioritize combating the virus 5. This postponing, it was important but will cause an impact in the economy at the public health system from Brazil this year and in the next years. Therefore, this study aims to present the economic impact caused by COVID-19 pandemics in the public heal system, SUS, of Brazil. Data about total hip arthroplasty (THA) and total knee arthroplasty (TKA) in Brazil were collected from the TABNET portal of the Brazilian Health Ministry/Datasus 6. It was collected information per month about hospitalization authorization (AIH), and total cost per AIH. The information regards the period of January to June from years 2015 to 2020.Introduction
Methods
The release of metallic debris can promote many adverse tissue reactions, as metallosis, necrosis, pseudotumors and osteolysis 1–3. This debris is mainly generated by the fretting-corrosion mechanism due to the geometric difference in the head-stem interface 4. Retrieval and Four stems (n = 4) from five (5) distinct manufacturers (A, B, C, D, and E) were used to evaluate the roughness of the trunnion. All the stems are similar to the classical Exeter stem design, with a 12/14 taper and a polished body surface. The roughness of trunnions was evaluated according to ISO 4287 and ISO 13565-2. The total assessment length was 4.8 mm with 0.8 mm cut-off. The first and last 8.33% of assessment length were not considered. The measurements of all samples were made in a rugosimeter with 2 µm feeler ITP (Völklingen, Germany), the velocity of 0.5 mm.s-1, and a force of 1.5 mN. The calibration was made at 20 ºC and relative humidity at 50%. The Kruskal Wallis with post hoc Nemenyi test was used to evaluate the difference of Ra among the manufacturers. The confidence level was set at 5%.Introduction
Methods
The use of bone cement as a fixation agent has ensured the long-term functionality of THA implants 1. However, some studies have shown the undesirable effect of wear of stem-cement interface, due to the release of metals and polymeric debris lead to implant failure 2,3. Debris is generated by the micromotion together with a severely corrosive medium present in the crevice of stem-cement interface 3,4. FEA studies showed that micromotion can affect osseointegration and fretting wear 5,6. The aim of this research is to investigate if the micromotions measures from The For the computational analysis, the same testing configurations were modeled on software ANSYS. The analysis was performed using linear isotropic elasticity for both stem (E=193GPa; ⱱ=0.27; σy=400MPa) and PMMA cement (E=2.7GPa; ⱱ=0.35; σu=76MPa)7,8. A second-order tetrahedral element was used to mesh all components with a size of 0.5 mm in the stem-cement contact area, increasing until 1.0 mm outside from them. A frictional contact (µ=0.25) with an augmented Lagrange formulation was used. The third cycle of loading was evaluated and a variation of sliding distance less than 10% was set as convergence criteria. The micromotion was measured as the sliding distance on the stem-cement interface.Introduction
Methods
