The EndoCert®-Initiative system sets specific requirements for the structural, process and result quality in certified Arthroplasty Centers in Germany. However, it remains unclear to what extent the certification process can increase the quality in total hip and knee arthroplasty. Aim of the comparative retrospective study is to analyse the change in quality of total hip arthroplasty in a communal hospital before and after the certification process. All primary total hip arthroplasties (n = 366) between 2013 and 2016 were included in the study retrospectively and grouped by treatment period. Treatment was performed in group 1 without clinical pathways, in group 2 pathway-controlled without a valid certificate and in group 3 pathway-controlled after final completion of the certification process. Outcome quality was analysed using quality indicators defined by the EndoCert-Initiative and further predefined indicators. Results show quality improvement under certified pathway-controlled treatment, e.g. time of surgery, cup and stem positioning, blood transfusion rate, periprosthetic fractures. However, improvements were not significantly in all cases and limitations must be recognized. Positive effects of the certification process legitimate capital investment and efforts. Further quality indicators may be implemented in the certification process to improve quality of treatment in arthroplasty.