Statistics
fracture
IMPACTION
Normality of the data distribution was assessed by probability plots. Data following a normal distribution was reported with 95% confidence intervals (CI 95%) and data with non-normal distribution was reported as median values with interquartile range (IQR). Hypotheses of no difference for clinical, patient reported, and radiographic variables comparing the HA-coated group with the NON-coated group was tested statistically using Student’s t-test for normally distributed data Wilcoxon signed-rank test for data with a non-normal distribution. Chi-squared test was used to test categorical data, i.e., screw placement in the femoral head.RSA measured migration during the follow-up was evaluated as 1) screw migration – with reference to the femoral head/neck segment, and as 2) fracture migration (femoral head/neck segment) – with reference to the trochanter region. Further, fracture migration from baseline to 6 weeks (impaction phase) and from 6 weeks to 6 months (stabilization phase) was compared for all patients. Hypotheses of no difference in screw migration between the HA-coated and the NON-coated group was analyzed using univariate repeated measurement analysis (mixed model) on follow-up time with group HA-coated/NON-coated as fixed effects, and patient as random effect. We used pairwise group comparisons for each follow-up time to describe differences. Unequal standard deviations and correlations of the groups were considered in the analyses. Normal distribution of the mixed-model residuals was tested by Q–Q plots. As no statistically significant or clinically important differences were found between the groups regarding screw migration, the groups were combined for the further statistical analysis (mixed model) of fracture migration during the impaction phase and stabilization phase. Repeatability of RSA double examinations were estimated and reported as absolute mean differences and prediction intervals (1.96 × SD). We used Stata 16 (StataCorp, College Station, TX, USA) for statistical analysis. The statistical significance was set at 