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Aims: Primary fixation of cementless implants is achieved through press-fit. This study aimed to simulate the press-fit of pegs in bone analogue with finite element analysis (FEA) with as few parameters as possible, thereby providing a useful tool for the quick evaluation of potential device designs. Methods: Push-in and pull-out of smooth and porous pegs in plastic trabecular bone analogue (20 PCF, Sawbones) were modelled using a finite element approach. The model was validated by comparing the maximum push-in and pull-out forces from FEA to the corresponding peg push-in/pull-out testing in plastic bone. Results: The results from FEA agreed well with experiments for the smooth pegs at surgically-relevant interferences (0.6–0.9 mm). Error was under 18.4 % for maximum push-in forces and 6.9 % for maximum pull-out forces. When the same fracture strain value was used to simulate porous pegs, the errors were 9.4 % and 14.7 % for push-in and pull-out force, respectively. Conclusion: The proposed method of simulating peg press-fit required only two sets of input data: the uniaxial material curve of the plastic bone from which the fracture strain could also be derived, and the coefficient of friction between the plastic bone and the peg. The method can be applied to gain insight into the potential of new fixation component designs before progression to experimental testing.

Metabolic residue concentration data for two licit drugs (nicotine and alcohol), three medications of abuse (morphine, methadone and codeine) and six illicit drugs (cannabis, cocaine, amphetamine, methamphetamine, ecstasy and heroin) were obtained from raw wastewater samples collected from 44 Slovenian educational institutions are presented. Also, concentrations obtained at one secondary school during a preliminary study is provided. The wastewater samples were collected at the end of the 2018/2019 academic year using time proportional sampling and analysed for 16 drug residues, extracted using solid-phase extraction and analysed using ultra-performance liquid chromatography hyphenated to tandem mass spectrometry (UPLC-MS/MS). Residues of nicotine and alcohol were determined by direct injection of filtered wastewater onto the UPLC. Concentrations data were studied based on educational level (primary, secondary and tertiary) and institution type (secondary schools: gymnasiums, vocational and technical schools, multi-programme schools; higher education institutions: natural sciences and social sciences), geographic location (municipalities) and degree of urbanisation (urban and non-urban areas). Due to the large number of different educational institutions included in the study, provided datasets are valuable for further studies on drug consumption patterns among young people. Drug presence and prevalence data for primary schools (6–15 years) offer an objective insight into drugs present in the early stage of a young person's development and help establish effective prevention programs. More details on the study can be found in [1].