Limitations
THA, pain
The present study was conducted in a single-blinded study design due to regulations in Germany (medication used intraoperatively only in the ERAS group), therefore, the surgeon had to know which study group patients were assigned to. Nevertheless, data were evaluated by an independent team of physician assistants and physiotherapists, therefore, bias should be reduced to an absolute minimum. Secondly, immobilized patients were excluded in this study, leaving unclear how ERAS THA affect the success of an older immobile and patient collective with comorbidities. To guarantee standardized and controlled study conditions, the follow-up period in our study was limited to one week, so mid-/long-term results are not available. Nonetheless, the short follow-up could also be stated as a strength of the study as the clear and standardized setup with two arms and equal LOS considering THA can rarely be found within other countries’ health care systems. With this elaborate prospective randomized study, qualitative conclusions about postoperative outcome can be made. Most high-quality studies on this topic were surveying length-of-stay (LOS), but to date, no data was available regarding mobilization, function, pain and satisfaction—the reason, why we conducted this study. In the future, prospective multi-center longer term studies in a randomized controlled study design should be undertaken to extend the acquired knowledge in this study and measure and conclude pain, functional outcome and quality of life improvements after ERAS THA.