Aims Periprosthetic femoral fractures (PPF) are a serious complication of total hip arthroplasty (THA) and are becoming an increasingly common indication for revision arthroplasty with the ageing population. This study aimed to identify potential risk factors for PPF based on an analysis of registry data. Methods Cases recorded with PPF as the primary indication for revision arthroplasty in the German Arthroplasty Registry (Endoprothesenregister Deutschland (EPRD)), as well as those classified as having a PPF according to the International Classification of Diseases (ICD) codes in patients’ insurance records were identified from the complete datasets of 249,639 registered primary hip arthroplasties in the EPRD and included in the analysis. Results The incidence of PPFs was higher (24.6%; 1,483) than reported in EPRD annual reports listing PPF as the main reason for revision (10.9%; 654). The majority of fractures occurred intraoperatively and were directly related to the implantation process. Patients who were elderly, female, or had comorbidities were at higher risk of PPFs (p < 0.001). German hospitals with a surgical volume of < 300 primary procedures per year had a higher rate of PPFs (p < 0.001). The use of cemented and collared prostheses had a lower fracture risk PPF compared to uncemented and collarless components, respectively (both p < 0.001). Collared prostheses reduced the risk of PPF irrespective of the fixation method and hospital’s surgical volume. Conclusion The high proportion of intraoperative fractures emphasises the need to improve surgeon training and surgical technique. Registry data should be interpreted with caution because of potential differences in coding standards between institutions. Cite this article: Bone Joint J 2021;103-B(4):650–658.

ZusammenfassungSeit 10 Jahren erfasst und verfolgt das Endoprothesenregister Deutschland (EPRD) endoprothetische Eingriffe an Hüft- und Kniegelenk. Trotz der Freiwilligkeit des Registers konnten so bereits mehr als 2 Mio. Operationen in Deutschland erfasst werden. Das EPRD zählt somit als drittgrößtes Register der Welt. Die hochgranulare Klassifikation der EPRD-Produktdatenbank, in der mittlerweile mehr als 70.000 Artikel hinterlegt sind, soll zum internationalen Standard erhoben werden. Die Verknüpfung von Fällen mit spezifischen Implantatdaten sowie Routinedaten der Krankenkassen ermöglicht valide Standzeitanalysen. Auf dieser Basis erhalten Kliniken, Hersteller, aber auch die Fachöffentlichkeit spezifische Ergebnisse, die zur Verbesserung der Qualität in der Endoprothetik beitragen. Zunehmend internationale Wahrnehmung erhält das Register auch durch Publikationen in „peer-reviewed journals“. Ein Antragsverfahren ermöglicht zudem den Zugriff auf EPRD-Daten für „Dritte“. Darüber hinaus hat das EPRD ein Frühwarnsystem etabliert, um Auffälligkeiten zu detektieren. Softwaregestützt meldet das EPRD mögliche Fälle von Implantat-Mismatch an die betreffenden Kliniken. Die EPRD-Erfassung wird im Rahmen eines Probebetriebs im Jahr 2023 um Patientenbefragungen zur Zufriedenheit, sog. PROMs, ergänzt. Auch die Erfassung des Operateurs wird perspektivisch folgen.

National joint registries are gaining more and more importance in the fields of implant monitoring/outlier detection and quality of care. The German Arthroplasty Registry (EPRD) was established in 2010 for the purpose of observing the impact of primary hip and knee arthroplasty on the German population. Having now over one million documentations, we introduce the structure of the EPRD and detail the process of data collection. We report on some preliminary trends and contrast these with findings from other joint registries. We introduce the overhauled Arthroplasty Library, that resulted from an international collaboration with National Joint Registry of England, Wales and Northern Ireland. Cite this article: EFORT Open Rev 2019;4 DOI: 10.1302/2058-5241.4.180064

Background: Prosthetic joint infection (PJI) is one of the most frequent and devastating causes of shortterm revision total knee arthroplasty (TKA). In vitro evidence suggests ceramic surfaces demonstrate resistance to biofilm, but the clinical effect of bearing surface modifications on the risk of PJI remains unclear. This premier registry-based study examines the influence of ceramic bearing surface coatings on the outcome in cemented primary TKA. Methods: In total, 117,660 cemented primary TKAs in patients with primary osteoarthritis recorded in the German arthroplasty registry since 2012 were followed up for a maximum of 3 years. The primary endpoint was risk of revision for PJI on ceramic coated and uncoated cobalt-chromium-molybdenum femoral components. Propensity score matching for age, gender, obesity, diabetes mellitus, depression and Elixhauser comorbidity index, and substratification on common design twins with and without coating was performed. Results: In total, 4637 TKAs (85.1% female) with a ceramic-coated femoral component were identified, 42 had been revised for PJI and 122 for other reasons at 3 years. No survival advantage due to the risk of revision for PJI could be determined for ceramic-coated components. Revision for all other reasons demonstrated a significant higher rate for TKAs with ceramic-coated components. However, the results of this were confounded by a strong prevalence (20.7% vs 0.3%) of metal sensitivity in the ceramic-coated group. Conclusion:No evidence of reduced risk for PJI due to ceramic-coated implants in cemented primary TKA was found. Further analysis for revision reasons other than PJI is required.