Long-term results of the M2A-38-mm metal-on-metal articulation

Abstract Background Large-diameter head metal-on-metal (MoM) bearings in total hip arthroplasty (THA) are associated with increased whole blood levels of chromium (Cr) and cobalt (Co), adverse reactions to metal debris (ARMD) and poor survival rates. The prevalence of high metals concentrations, ARMD and the risk of revision surgery may vary significantly among different prostheses and long-term studies are few. This single-center study reports the long-term results of the 38-mm MoM bearing system. Materials and methods Between 2003 and 2009, 80 patients received primary cementless THA using the large head metal-on-metal articulating surface M2A-38 cup (Biomet, Inc., Warsaw, IN, USA) at a single institution. Forty-five patients (53 hips) were retrospectively reviewed for a mean follow-up of 127 months. Results Two cups were revised. The cumulative implant survival rate was 98% at 10 years and 74% at 13 years. In the whole sample, the median Co and Cr concentrations were 4.8 µg/L (IQR 1.2–4.9 µg/L) and 2.5 µg/L (IQR 0.6–3.0 µg/L), respectively. The incidence of Co or Cr levels > 7 μg/L was 15.5% and the incidence of ARMD was 3.8%. Co and Cr levels showed no correlation with cup inclination, Harris Hip Score, or total Hip Disability and Osteoarthritis Outcome score. Conclusions Our results confirm that the problems of release of metal ions with the possible increase of metal circulating levels and of adverse reactions may also occur in the long term with this brand of MoM large head, and that a structured follow-up program is mandatory. Levels of evidence Level 4

Operational strategies to deal with the COVID-19 emergency: recommendations from the Italian national society SIAGASCOT following the introduction of vaccines against the SARS-CoV-2 infection

Background: This article aims to present the operational recommendations adopted by the Italian national society for orthopaedic surgery, arthroscopy, and sports medicine (SIAGASCOT) in managing patients eligible to undergo elective orthopaedic surgery during the COVID-19 pandemic after the beginning of a national vaccination campaign. Materials and methods: An extensive literature search, analysing medical databases and scientific societies protocols, was performed to support this document. A four-step approach was used: 1-definition of priorities; 2-definition of significant clusters of interventions; 3-extraction of recommendations from international literature; and 4-adaptation of the recommendations to the specific features of the Italian healthcare system. Results: Three operational priorities were defined ("continuity of care and containment of the virus spread", "examination of waiting lists", and "definition of the role of vaccines"), six significant clusters of intervention were identified, and recommendations regarding the risk management for healthcare staff and hospital facility as well as the preoperative, in-hospital, and postoperative management were produced. Patient selection, preoperative screening, and pre-hospitalization procedures, which are regarded as pivotal roles in the safe management of patients eligible to undergo elective orthopaedic surgery, were analysed extensively. Conclusions: This document presents national-wide recommendations for managing patients eligible to undergo elective orthopaedic surgery with the beginning of the vaccination campaign. This paper could be the basis for similar documents adapted to the local healthcare systems in other countries. Level of evidence: Level IV

Nucleocapsid protein structures from orthobunyaviruses reveal insight into ribonucleoprotein architecture and RNA polymerization

Wellcome Trust through a jointly held project grant [WT091783MA to J.N.B. and T.A.E.], a project grant [WT084332MA to J.N.B.] and a studentship [086774/Z/ 08/Z to K.C.D.]; BBSRC and The Health Protection Agency through a studentship (to S.J.T.); EPSRC through a White Rose studentship (to D.S.). Funding for open access charge: Wellcome Trust.All orthobunyaviruses possess three genome segments of single-stranded negative sense RNA that are encapsidated with the virus-encoded nucleocapsid (N) protein to form a ribonucleoprotein (RNP) complex, which is uncharacterized at high resolution. We report the crystal structure of both the Bunyamwera virus (BUNV) N-RNA complex and the unbound Schmallenberg virus (SBV) N protein, at resolutions of 3.20 and 2.75 A, respectively. Both N proteins crystallized as ring-like tetramers and exhibit a high degree of structural similarity despite classification into different orthobunyavirus serogroups. The structures represent a new RNA-binding protein fold. BUNV N possesses a positively charged groove into which RNA is deeply sequestered, with the bases facing away from the solvent. This location is highly inaccessible, implying that RNA polymerization and other critical base pairing events in the virus life cycle require RNP disassembly. Mutational analysis of N protein supports a correlation between structure and function. Comparison between these crystal structures and electron microscopy images of both soluble tetramers and authentic RNPs suggests the N protein does not bind RNA as a repeating monomer; thus, it represents a newly described architecture for bunyavirus RNP assembly, with implications for many other segmented negative-strand RNA viruses.Publisher PDFPeer reviewe