Periprosthetic joint infection (PJI) is a serious complication after total joint arthroplasty. In the course of a PJI, superinfections with pathogens that do not match the primary infecting micro-organism may occur. To our knowledge, there are no published data on the outcome of such infections in the literature. The aim of this study was to assess the outcome of PJI with superinfections with a difficult-to-treat (DTT) pathogen. Data of 169 consecutive patients with PJI were retrospectively analyzed in this single-center study. Cases were categorized into: Group 1 including non-DTT-PJI without superinfection, Group 2 DTT-PJI without superinfection, Group 3 non-DTT-PJI with DTT superinfection, and Group 4 non-DTT-PJI with non-DTT superinfection. Group 3 comprised 24 patients and showed, after a mean follow-up of 13.5 ± 10.8 months, the worst outcome with infection resolution in 17.4% of cases (p = 0.0001), PJI-related mortality of 8.7% (p = 0.0001), mean revision rate of 6 ± 3.6 (p < 0.0001), and duration of antibiotic treatment of 71.2 ± 45.2 days (p = 0.0023). PJI caused initially by a non-DTT pathogen with a superinfection with a DTT pathogen is significantly associated with the worst outcome in comparison to non-DTT-PJI, PJI caused initially by a DTT pathogen, and to non-DTT-PJI with a non-DTT superinfection.

Rifampin is one of the most important biofilm-active antibiotics in the treatment of periprosthetic joint infection (PJI), and antibiotic regimens not involving rifampin were shown to have higher failure rates. Therefore, an emerging rifampin resistance can have a devastating effect on the outcome of PJI. The aim of this study was to compare the incidence of rifampin resistance between two groups of patients with a PJI treated with antibiotic regimens involving either immediate or delayed additional rifampin administration and to evaluate the effect of this resistance on the outcome. In this retrospective analysis of routinely collected data, all patients who presented with an acute/chronic PJI between 2018 and 2020 were recorded in the context of a single-center comparative cohort study. Two groups were formed: Group 1 included 25 patients with a PJI presenting in 2018–2019. These patients received additional rifampin only after pathogen detection in the intraoperative specimens. Group 2 included 37 patients presenting in 2019–2020. These patients were treated directly postoperatively with an empiric antibiotic therapy including rifampin. In all, 62 patients (32 females) with a mean age of 68 years and 322 operations were included. We found a rifampin-resistant organism in 16% of cases. Rifampin resistance increased significantly from 12% in Group 1 to 19% in Group 2 (p < 0.05). The treatment failure rate was 16% in Group 1 and 16.2% in Group 2 (p = 0.83). The most commonly isolated rifampin-resistant pathogen was Staphylococcus epidermidis (86%) (p < 0.05). The present study shows a significant association between the immediate start of rifampin after surgical revision in the treatment of PJI and the emergence of rifampin resistance, however with no significant effect on outcome.

Periprosthetic shoulder infection (PSI) remains a devastating complication after total shoulder arthroplasty (TSA). Furthermore, there is a paucity in the literature regarding its diagnostic and therapeutic management, especially the absence of therapy concepts devised exclusively for PSI. The aim of the presenting study is to examine the characteristics and outcome of patients with PSI who were treated according to well-established algorithms developed originally for periprosthetic joint infection (PJI) of the hip and knee and determine if these algorithms can be applied to PSI. This single-center case series included all patients with a PSI presenting between 2010 and 2020. Recorded parameters included age, sex, affected side, BMI, ASA score, Charlson comorbidity index, preoperative anticoagulation, indication for TSA (fracture, osteoarthritis or cuff-arthropathy), and type of infection (acute or chronic PSI). The outcome was divided into treatment failure or infect resolution. Staphylococcus epidermidis and aureus were the commonest infecting pathogens. Acute PSI was mainly treated with debridement, irrigation, and retention of the prosthesis (DAIR) and chronic cases with two/multiple-stage exchange. The treatment failure rate was 10.5%. C-reactive protein was preoperatively elevated in 68.4% of cases. The mean number of operative revisions was 3.6 ± 2.6, and the mean total duration of antibiotic treatment was 72.4 ± 41.4 days. The most administered antibiotic was a combination of clindamycin and fluoroquinolone. In summary, the data of the current study suggest that therapeutical algorithms and recommendations developed for the treatment of PJI of the hip and knee are also applicable to PSI.

The number of revision knee arthroplasties (rTKA) is growing significantly as is the use of intramedullary stems for optimized stability. The choice of the most appropriate stem fixation method is still controversial. The purpose of this meta-analysis is to compare cemented versus cementless stem fixation in rTKA. Publications with patients undergoing rTKA with a follow-up > 24 months were systemically reviewed. Extracted parameters included total revision and failure rates for any reason, incidence of aseptic loosening, periprosthetic infection, and radiolucent lines, as well as the clinical outcome. A statistical regression analysis was then performed on all extracted clinical and radiological outcome data. A total of 35 publications met the inclusion criteria and were included and analyzed. Overall, 14/35 publications compared cementless versus cemented stem fixation, whereas 21/35 publications investigated only one stem fixation method. There were no significant differences in revision (p = 0.2613) or failure rates (p = 0.3559) and no differences in the incidence of aseptic loosening (p = 0.3999) or periprosthetic infection (p = 0.1010). The incidence of radiolucent lines was significantly higher in patients with cemented stems (26.2% versus 18.6%, p < 0.0001). However, no differences in clinical outcomes were observed. No superiority of a specific stem fixation method in rTKA was found. Rates of revision or failure for any reason as well as incidence of aseptic loosening and periprosthetic infection in cemented versus cementless stem fixation showed no significant difference. A higher incidence of radiolucent lines was observed in cemented stem fixation; however, no effect was observed on the clinical outcome.

Zusammenfassung Hintergrund Krankenhäuser der Grund- und Regelversorgung bzw. regionale Traumazentren spielen eine essenzielle Rolle in der Versorgung hüftgelenknaher Frakturen. Ziel Die vorliegende Arbeit untersucht den Zusammenhang zwischen patientenbezogenen Parametern und der Klinikmortalität sowie dem Auftreten von Komplikationen bei solchen Frakturen an einem regionalen Traumazentrum. Methoden Im Rahmen einer retrospektiven Studie wurden die Daten von allen Patienten, die über 2 Jahre an einem regionalen Traumazentrum mit einer hüftgelenknahen Fraktur aufgenommen wurden, erfasst. Eingeschlossen wurden nur Patienten älter als 60 Jahre. Die patientenbezogenen Parameter umfassten Alter, Geschlecht, Frakturlokalisation, Methode der operativen Versorgung, Operationszeitpunkt, Dauer der Operation und des stationären Aufenthalts, Bluttransfusion, Komplikationen, Komorbiditäten, Einnahme von Antikoagulanzien und Notwendigkeit einer postoperativen intensivmedizinischen Behandlung. Der Zusammenhang zwischen diesen Parametern und der Klinikmortalität sowie dem Auftreten von Komplikationen wurde untersucht. Ergebnisse Daten von 360 Patienten mit 335 Operationen (w:m 225:110) mit einem Alter von 83 ±8 Jahren wurden erfasst. Die Klinikmortalität lag bei 7,76 % (n = 26) und erhöhte sich bei Alter > 85 Jahren (Odds Ratio [OR] 5,126; 95%-Konfidenzintervall [95 %-KI] 0,665–39,498; p = 0,1167), männlichem Geschlecht (OR 1,85 95%-KI [0,82–4,14]; p = 0,0555), Zeitpunkt der Operation > 24 h (OR 1,896 95%-KI [0,661–5,441]; p = 0,2341), ≥ 3 Vorerkrankungen (OR 10,61 95%-KI [3,681–27,501]; p < 0,0001), Einnahme von Antikoagulanzien (OR 6,19 95%-KI [2,69–14,24]; p < 0,0001) und notwendiger postoperativer intensivmedizinischer Behandlung (OR 5,9 95%-KI [2,56–13,76]; p < 0,0001). Schlussfolgerung In der vorliegenden Studie fanden sich statistisch signifikante Einflüsse der Anzahl der Komorbiditäten, der Einnahme von Antikoagulanzien sowie der intensivmedizinischen Behandlung auf die Klinikmortalität bei Patienten mit hüftgelenknahen Frakturen an einem regionalen Traumazentrum.

Inflammation models with the proinflammatory cytokine interleukin-1β (IL-1β) are widely used in the in vitro investigation of new therapeutic approaches for osteoarthritis (OA). The aim of this study was to systematically analyze the influence of IL-1β in a 3D chondral pellet culture model. Bovine articular chondrocytes were cultured to passage 3 and then placed in pellet culture. Titration of IL-1β (100–0.1 ng/mL) was performed with both human and bovine recombinant protein in chondrocyte culture for 2 weeks. Gene expression of anabolic (collagen 2, aggrecan, cartilage oligomeric protein (COMP), proteoglycan-4 (PRG-4)), catabolic matrix metallo proteinases (MMP-3, MMP-13), dedifferentiation (collagen 1) markers and inflammatory cytokines IL-6 and IL-8 was determined. Analysis of the cell culture medium was performed for the inflammatory markers IL-6 and nitric oxide (NO). In general, the influence of IL-1β was shown by a decrease in the expression of anabolic markers (collagen 2, aggrecan, PRG-4), whereas the catabolic markers MMP-3 and MMP-13 as well as the inflammatory markers IL-6 and IL-8 were significantly increased. This was observed both at the early time point (day 4) and at the late time point (day 14). The described inflammatory effects were confirmed by increased concentration-dependent release of NO and IL-6. The threshold concentration for a detectable effect compared to control differed between groups, but was reached earlier by homologous application of IL-1β. This study provides a systematic evaluation of IL-1β-specific effects on chondrocytes in a 3D pellet culture model, which is highly relevant for comparisons of studies in OA-specific drug development.