Die Pfanneninklinationsmessung in der Beckenübersichtsaufnahme: Ein Qualitätsindikator nach Hüft-TEP-Primärimplantation?

Retrospective Comparative Study of the Influence on Quality of Primary Total Hip Arthroplasty by the EndoCert-Certification System in a Communal Hospital

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.

[Discrepancy between radiographic and true cup position after total hip arthroplasty : Are we interpreting our radiographic quality indicators correctly? Video article]

BACKGROUND

After total hip arthroplasty (THA), objective postoperative quality control is done via X‑rays by as component position assessment. The cup position is defined by its version and inclination. However, there is a discrepancy between radiographically measured and true (anatomic) cup position, which may lead to misinterpretation.

METHODS

To visualize the discrepancy between true and radiographically measured cup position, in this video, a cup holder was used to set the angular cup version and inclination. Hereby, the cup position (anteversion and inclination) can be characterized in its radiographic and anatomic definition in greater detail. The viewer of this video should receive an impression as to when radiographically measured cup angles must be considered with caution.

RESULTS

In a simultaneous X‑ray and image sequence, this video shows decreased radiographic inclination measurement with increasing anterior rotation of the cup exceeding 20° of anteversion, yet with unchanged true inclination on the cup holder. Isolated consideration of the radiographic angles of anteversion and inclination may cause misinterpretation of true cup position. In pectoral illustration we show that variations in cup version and inclination may remain undetected when considering isolated the radiographic cup parameters.

CONCLUSION

True cup position in its anatomical definition can be calculated from the radiographically measured position. For this purpose, both cup parameters (radiographic anteversion and radiographic inclination) have to be taken into account.