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Introduction: Atraumatic necrosis of the femoral head (AFHN) is a common disease with an incidence of 5000–7000 middle-aged adults in Germany. There is no uniform consensus in the literature regarding the configuration of the bone in AFHN. The clinical picture of our patients varies from very hard bone, especially in idiopathic findings, and rather soft bone in cortisone-induced necrosis. A better understanding of the underlying process could be decisive for establishing a morphology-dependent approach. The aim of this study is the closer examination of the condition of the bone in the AFHN compared to the primary hip osteo arthritis (PHOA). Materials and methods: The preparations were obtained as part of elective endoprosthetic treatment of the hip joint. Immediately after sample collection, thin-slice CT of the preserved femoral heads was performed to determine the exact density of the bone in the necrosis zone. Reconstruction was done in 0.8–1 mm layers in two directions, coronary and axial, starting from the femoral neck axis. Density of the femoral heads was determined by grey value analysis. The value in Hounsfield units per sample head was averaged from three individual measurements to minimize fluctuations. For biomechanical and histomorphological evaluation, the samples were extracted in the load bearing zone perpendicular to the surface of the femoral head. Group-dependent statistical evaluation was performed using single factor variance analysis (ANOVA). Results: A total of 41 patients with a mean age of 64.44 years were included. The mean bone density of the AFHN samples, at 1.432 g/cm3, was about 7% higher than in the PHOA group with a mean value of 1.350 g/cm3 (p = 0.040). The biomechanical testing in the AFHN group showed a 22% higher—but not significant—mean compressive strength (20.397 MPa) than in the PHOA group (16.733 MPa). On the basis of histological analysis, no differentiation between AFHN and PHOA samples was possible. Conclusions: The present study (NCT, evidence level II) shows that AFHN has a very well detectable higher bone density compared to PHOA. However, neither biomechanical stress tests nor histomorphological evaluation did show any significant difference between the groups. The results allow the conclusion that there is no "soft" necrosis at all in the AFHN group. [ABSTRACT FROM AUTHOR]

Correction to: Archives of Orthopaedic and Trauma Surgery https://doi.org/10.1007/s00402-021-... The original version of this article unfortunately contained a mistake. The correct given name and family name should be: Alexander Hofmann - Benjamin Fischer - Stefan Schleifenbaum - Sascha Kurz - Melanie Edel - Gudrun Borte - Gabriele Lehmann - Andreas Roth The original article has been corrected. [Extracted from the article]

Introduction. The incidence of early deep infection after arthroplasty of the knee is very low but could represent a serious future problem. Material and methods. The authors report on a 71-year-old woman with gonarthritis who was supplied with a total knee endoprosthesis and developed a local infection followed by septic shock. Results. The infection was evidently caused by a multiresistant Staphylococcus aureus (Staph. aureus). The primary clinical signs closely resembled a necrotizing fasciitis. Systemic and local application of vancomycin led to an improvement of the symptoms at secondary sites, but only the amputation of the primarily infected leg was lifesaving. Conclusion. In order to prevent such events, the authors recommend a number of additional presurgical measures. Firstly, a swab from the nose and throat should be taken prior to an elective surgery in patients with elevated risk of immunodeficiency, for example in patients with diabetes. The diabetes should be adequately treated before an elective operation is undertaken. Secondly, an early punction of the knee joint should be carried out if there is any doubt regarding inflammation. Isolated infectious agents should be grounds for early revision, which should always be completed with a rinsing procedure and with adequate antibiotics. Immunotherapy should be taken into consideration. Antiepidemic measures are recommended in cases with known Staph. aureus. [ABSTRACT FROM AUTHOR]