[10 Years of the German Arthroplasty Registry-EPRD: what has been achieved?] / 10 Jahre Endoprothesenregister Deutschland (EPRD): was wurde erreicht?

The German Arthroplasty Registry (EPRD) has been accumulating data on hip and knee arthroplasty procedures for 10 years. Even though the EPRD is a voluntary registry, it currently includes more than 2 million documented surgical procedures in Germany. This ranks the EPRD as the third largest registry in the world. The highly granular classification of the EPRD product database, which currently includes more than 70,000 components, is set to become the international standard. The linkage of hospital case data with specific implant component data and routine data from health insurance providers enables robust arthroplasty survival analyses. This provides hospitals, manufacturers, and the specialist community with access to specific results that contribute to improving arthroplasty quality. The registry is gaining increasing international recognition by publishing in peer-reviewed journals. An application procedure also allows "third-party" data access. Furthermore, the EPRD has also established an early warning system to detect anomalies in outcome. Software-based detection of potential implant component mismatches allows notification of hospitals concerned. In 2023, the EPRD will trial extending its data collection to include patient satisfaction surveys (i.e., patient-reported outcome measures), and subsequently to surgeon-specific data.

[Standard and special liner in primary hip arthroplasty : Current study and survey results from the German Arthroplasty Registry (EPRD)]. / Standard- und Spezialinlays in primärer Hüftendoprothetik : Aktuelle Studien- und Umfrageergebnisse aus dem Endoprothesenregister Deutschland (EPRD).

BACKGROUND: Instability constitutes the main reason for revision hip arthroplasties. Modified polyethylene liners are designed to improve the stability of a hip replacement. In July 2022 The Bone & Joint Journal published a study with data of the German Arthroplasty Registry (EPRD). The study investigated mechanical failure of standard and modified liner designs in primary, cementless total hip arthroplasty. Following the study, the EPRD conducted a survey of German clinics to research the utilization of lipped liners in primary total hip replacement. METHODS: The liner study included 151,096 primary, elective, cementless total hip arthroplasties. Data from November 2012 to November 2020 were obtained from the EPRD. Standard polyethylene liners were compared with lipped, angulated, offset and angulated/offset inlays. Cumulative incidences for endpoint revision due to mechanical complication were calculated with a competing risk analysis. The influence of other variables was investigated with a multivariate Cox regression. In the following online survey, 237 out of 789 hospitals completed a form. RESULTS AND CONCLUSION: In our analysis, only offset liners were, compared to standard liners, associated with a reduced risk of mechanical failure in a short to medium follow up. However, the resultant joint reaction force is increased with offset liners due to the lateralization of the hip center of rotation. Thus, the long-term performance of offset liners needs to be observed. Our survey indicated that lipped liners were implanted more often if the posterior approach was used. Moreover, lipped liners were mostly positioned with the elevated rim in the biomechanically less optimal posterior-superior quadrant. To improve stability it is suggested to position the elevated rim in the posterior-inferior quadrant.

Modified acetabular component liner designs are not superior to standard liners at reducing the risk of revision : an analysis of 151,096 cementless total hip arthroplasties from the German Arthroplasty Registry.

AIMS: Registry studies on modified acetabular polyethylene (PE) liner designs are limited. We investigated the influence of standard and modified PE acetabular liner designs on the revision rate for mechanical complications in primary cementless total hip arthroplasty (THA). METHODS: We analyzed 151,096 primary cementless THAs from the German Arthroplasty Registry (EPRD) between November 2012 and November 2020. Cumulative incidence of revision for mechanical complications for standard and four modified PE liners (lipped, offset, angulated/offset, and angulated) was determined using competing risk analysis at one and seven years. Confounders were investigated with a Cox proportional-hazards model. RESULTS: Median follow-up was 868 days (interquartile range 418 to 1,364). The offset liner design reduced the risk of revision (hazard ratio (HR) 0.68 (95% confidence interval (CI) 0.50 to 0.92)), while the angulated/offset liner increased the risk of revision for mechanical failure (HR 1.81 (95% CI 1.38 to 2.36)). The cumulative incidence of revision was lowest for the offset liner at one and seven years (1.0% (95% CI 0.7 to 1.3) and 1.8% (95% CI 1.0 to 3.0)). No difference was found between standard, lipped, and angulated liner designs. Higher age at index primary THA and an Elixhauser Comorbidity Index greater than 0 increased the revision risk in the first year after surgery. Implantation of a higher proportion of a single design of liner in a hospital reduced revision risk slightly but significantly (p = 0.001). CONCLUSION: The use of standard acetabular component liners remains a good choice in primary uncemented THA, as most modified liner designs were not associated with a reduced risk of revision for mechanical failure. Offset liner designs were found to be beneficial and angulated/offset liner designs were associated with higher risks of revision. Cite this article: Bone Joint J 2022;104-B(7):801-810.

Short versus conventional stem in cementless total hip arthroplasty : An evidence-based approach with registry data of mid-term survival.

BACKGROUND: Short-stemmed total hip arthroplasty (THA) is well established and gaining popularity in Germany. The perception that short stems may predispose to primary instability in the femur has resulted in a more thorough follow-up of younger patient cohorts than the typical uncemented THA population. To address this issue, an evidence-based approach is presented for a retrospective mid-term survival analysis of a large registry-based cohort in primary cementless THA comparing short stems with a matched group of conventional stems. MATERIAL AND METHODS: Propensity score matching (PSM, see Infobox 1) was used on 131,580 primary cementless THAs fulfilling the inclusion criteria performed between November 2012 and September 2019 and the cumulative probability of revision (CPR) of short and conventional stems for any reason, for reasons excluding prosthetic joint infection (PJI), and due to PJI were compared. RESULTS: After PSM at 1:1 balanced groups of 17,526 short stems and of 17,526 conventional stems were achieved demonstrating no significant difference for CPR for any reason and for reasons excluding PJI. Matched CPR for any reason was 2.9% (95% confidence interval, CI, 2.4-3.5%) 5 years after primary THA in the short stem and 3.1% (95% CI 2.7-3.4%) in the conventional stem group. The CPR excluding PJI was 2.2% (95% CI 1.7-2.7%) vs. 2.1% (95% CI 1.8-2.4%). In contrast, the incidence of PJI was statistically significant lower for short stems. CONCLUSION: For the considered period, there was no statistically significant survival difference in uncemented THA between comparison groups but a lower incidence for PJI in short-stem THA. Further analyses of registry data are required to rule out range of indications and late mechanical failure of short stems.

Ceramic Coating in Cemented Primary Total Knee Arthroplasty is Not Associated With Decreased Risk of Revision due to Early Prosthetic Joint Infection.

BACKGROUND: Prosthetic joint infection (PJI) is one of the most frequent and devastating causes of short-term 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.