Data analysis and statistics
Normality of continuous data was evaluated using quantile–quantile plots. Depending on the data distribution, continuous group baseline values were compared using one-way analysis of variance or Kruskal–Wallis test depending on the data distribution. Dichotomous data were analyzed using Chi-squared test or test for trend.Linear mixed models for repeated measurements were used to analyze femoral component migration and BMD change from baseline to 5-year follow-up as dependent variables and cemented single-peg, cemented twin-peg or cementless two-peg as the independent variable. Each patient was used as identifier for within subject variation. The data distribution assumptions were evaluated using model residual quantile–quantile plots and residual vs fitted plots. In case of statistically significant differences among groups, Bonferroni correction for multiple testing was applied. Migration data and BMD change data are presented as predicted means with 95% confidence intervals.STATA (version 16.1, StataCorp LLC, College Station, TX, USA) was used for statistical analyses. The level of significance was 0.05.