Patient-level hospital costs and length of stay after conventional versus minimally invasive total hip replacement: a propensity-matched analysis.

OBJECTIVES A current trend in total hip replacement (THR) is the use of minimally invasive surgery. Little is known, however, about the impact of minimally invasive THR on resource use and length of stay. This study analyzed the effect of minimally invasive surgery on hospital costs and length of stay in German hospitals compared with conventional treatment in THR. METHODS We used patient-level administrative hospital data from three German hospitals participating in the national cost data study. We conducted a propensity score matching to account for baseline differences between minimally invasively and conventionally treated patients. Subsequently, we estimated the treatment effect on costs and length of stay by conducting group comparisons, via paired t tests and Wilcoxon signed-rank tests, and regression analyses. RESULTS The three hospitals provided data from 2886 THR patients. The propensity score matching led to 812 matched pairs. Length of stay was significantly higher for conventionally treated patients (11.49 days vs. 10.90 days; P < 0.05), but total costs did not differ significantly (€6018 vs. €5986; P = 0.67). We found a difference in the allocation of costs, with significantly higher implant costs for minimally invasively treated patients (€1514 vs. €1375; P < 0.001) in contrast to significantly higher staff and overhead costs for conventionally treated patients. CONCLUSIONS Minimally invasive surgery was compared with conventional THR and was found to be associated with a reduced length of stay. Total hospital costs, however, did not differ between the two treatment groups, because of higher implant costs for minimally invasively treated patients.