Statistical Analysis With presumed achieved proportion of safe zone of Lewinnek in DAA and mini-PA, a minimum of 21 patients in each group were required, with an assumed two-sided alpha level of 5% and a power of 80%. Using body mass index (BMI), age and gender as covariates, 1:1 (DAA : micro-PA) propensity score matching was done. All the following analysis were calculated before and after propensity-score matching. The investigators used Mann-Whitney U test for comparison of continuous data and Chi-square test for categorical data. P < 0.05 was considered statistically significant. The software for analysis was STATA (StataCorp LP, Texas, USA).