Prosthesis-related infection is a serious complication for patients after orthopedic joint replacement, which is currently difficult to treat with antibiotic therapy. Consequently, in most cases, removal of the infected prosthesis is the only solution to cure the infection. It is, therefore, important to understand the comprehensive interaction between the microbiological situation and the host immune responses that lead to prosthesis infections. Evidence indicates that prosthesis infections are actually biofilm-correlated infections that are highly resistant to antibiotic treatment and the host immune responses. The authors reviewed the related literature in the context of their clinical experience, and discussed the possible etiology and mechanism leading to the infections, especially problems related to bacterial biofilm, and prophylaxis and treatment of infection, including both microbiological and surgical measures. Recent progress in research into bacterial biofilm and possible future treatment options of prosthesis-related infections are discussed.

Type I interferons (IFN-I) play a critical role in human antiviral immunity, as demonstrated by the exceptionally rare deleterious variants of IFNAR1 or IFNAR2. We investigated five children from Greenland, Canada, and Alaska presenting with viral diseases, including life-threatening COVID-19 or influenza, in addition to meningoencephalitis and/or hemophagocytic lymphohistiocytosis following live-attenuated viral vaccination. The affected individuals bore the same homozygous IFNAR2 c.157T>C, p.Ser53Pro missense variant. Although absent from reference databases, p.Ser53Pro occurred with a minor allele frequency of 0.034 in their Inuit ancestry. The serine to proline substitution prevented cell surface expression of IFNAR2 protein, small amounts of which persisted intracellularly in an aberrantly glycosylated state. Cells exclusively expressing the p.Ser53Pro variant lacked responses to recombinant IFN-I and displayed heightened vulnerability to multiple viruses in vitro—a phenotype rescued by wild-type IFNAR2 complementation. This novel form of autosomal recessive IFNAR2 deficiency reinforces the essential role of IFN-I in viral immunity. Further studies are warranted to assess the need for population screening.

Background and purpose Over the last 5 years, there has been increasing interest in reducing length of hospitalization (LOS) through accelerated programs. We examined the clinical outcome of patients undergoing a unicompartmental knee replacement (UKR) in an accelerated care program (A group) compared to a conventional care program (C group).Methods 40 patients randomized into 2 groups were included (A group: 17 patients; C group: 23 patients). Nausea, micturition problems, lower limb dysfunction, pain (VAS), opiate consumption, Knee Society score (KSS), day of discharge, rehospitalization within 3 months, contact with a general physician or nurse, and level of satisfaction were registered. Patients in the A group attended an information meeting. An intraarticular infiltration with Marcaine and adrenaline was used peroperatively. Patients in the C group had an epidural pump for 2 or 3 days. Patients in the A program were treated with NSAID and paracetamol postoperatively. Opiates were used in both groups in the case of breakthrough pain. The patients were considered ready for discharge when they were able to climb stairs to the second floor within 5 min.Results The median length of stay was 1 (1–3) day in the A group and 6 (4–7) days in the C group. The median pain score (VAS) at day 0 was 1 (0–3) in the A group and 5 (0–8) in the C group (p < 0.001). 11/23 of the patients in the C group had weakness of the lower limbs on day 1 due to the epidural; all patients in the A group were exercising on the day of the operation. Micturition problems necessitating intermediate catherization were more frequent in patients in the C program (19/23) than in patients in the A programme (3/17) (p = 0.001). There were no statistically significant differences between the two groups concerning nausea, average pain on days 1 and 2, use of opioids (during the first week postoperatively), KSS, contact with primary sector, level of satisfaction, or level of confidence.Interpretation We achieved a reduction in LOS of 5 days without affecting the clinical outcome.

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