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CT and advanced computer-aided design techniques offer the means for designing customised femoral stems. Our aim was to determine the Hounsfield (HU) value of the bone at the corticocancellous interface, as part of the criteria for the design algorithm. We obtained transverse CT images from eight human cadaver femora. The proximal femoral canal was rasped until contact with dense cortical bone was achieved. The femora were cut into several sections corresponding to the slice positions of the CT images. After obtaining a computerised image of the anatomical sections using a scanner, the inner cortical contour was outlined and transferred to the corresponding CT image. The pixels beneath this contour represent the CT density of the bone remaining after surgical rasping. Contours were generated automatically at nine HU levels from 300 to 1100 and the mean distance between the transferred contour and each of the HU-generated contours was computed. The contour generated along the 600-HU pixels was closest to the inner cortical contour of the rasped femur and therefore 600 HU seem to be the CT density of the corticocancellous interface in the proximal part of cadaver femora. Generally, femoral bone with a CT density beyond 600 HU is not removable by conventional reamers. Thus, we recommend the 600 HU threshold as one of several criteria for the design of custom femoral implants from CT data. Advances in radiology and in computerised design have allowed human anatomy to be reconstructed in three-dimensional (3D) geometrical and solid models. This has prompted orthopaedic surgeons and biomechanical engineers to develop customised joint implants in order to improve the fit between the prosthesis and the surrounding cortical bone. There have been several studies on the design of such customised femoral stems, 1-6 but the imaging techniques and the design criteria of the implants have differed. Although conventional radiographs are used in the design of femoral stems, CT is currently the most accurate method for describing the anatomy of the proximal femur. 7 On the CT image the endosteal surface appears irregular and in the proximal direction increasingly consists of can-cellous bone. The CT images reflect this by depicting a transitional zone with increasing density towards the compact cortical bone. When the surgeon prepares the canal for the femoral stem, he will remove most of the cancellous bone to allow the implant to rest on bone with sufficient mechanical strength. Our aim was to assess in Hounsfield units (HU) the CT density of the inner cortical surface of the proximal femur after this bone had been removed. One HU is defined as a number on a density scale in which the X-ray absorption of water has been assigned the value of zero and the air the value of-1000. Material and Methods We used eight fresh-frozen human cadaver femora from individuals with a mean age of 69 years (43 to 84). The specimens appeared normal on gross inspection and on radiological examination. Two plastic rods were fixed along the femur to ...

Objective While there are literature reporting increased incidence of hair loss in COVID‐19 patients, insufficient evidence exists on the topic to date. This review aims to identify the existing evidence and clinical characteristics of hair loss with COVID‐19 infection. Methods Following the PRISMA Extension for Scoping Reviews, MEDLINE and EMBASE were searched for all peer‐reviewed articles with relevant keywords including “Alopecia,” “Telogen Effluvium (TE),” and “COVID‐19” from their inception to November 20, 2021. Results A total of 26 articles, with 9 observational studies and 17 case reports or series (a total of 58 cases), were included. Most studies dealt with TE. There were no clear trends between COVID‐19 severity and the extent of hair loss. Analysis of the 58 cases also found similar results with most of the cases being female (82.8%), the median onset of hair loss of 2.0 months, and the median time to recovery of hair loss of 5.0 months with a resolution rate of 95%. Conclusion While this systematic review revealed uncertainty and a lack of strong evidence regarding the association of COVID‐19 and hair loss, hair loss in COVID‐19 may mainly include TE and be reversible in nature. Future studies are warranted to determine the detailed pathophysiology and risk factors of hair loss in COVID‐19, including possible roles of estrogen, progesterone, and pro‐inflammatory cytokines.

Immune‐related adverse events (irAE) were reported to be associated with better outcomes in various cancers treated with the immune checkpoint inhibitor nivolumab. Considering that their development depends on host immune activation, irAE may reflect antitumor response in mucosal melanoma (MM). This single‐center retrospective study including patients with advanced MM receiving nivolumab monotherapy between August 2014 and September 2018 investigated whether the development of irAE was associated with clinical efficacy. The study patients were divided into those with and without irAE, and treatment efficacy and safety were evaluated. The study cohort of 27 patients included 20 (74%), six (22%) and one (4%) patient with primary MM in the head and neck, genitourinary and anorectal regions, respectively. The irAE onset was not significantly associated with the objective response rate in patients while it was significantly associated with the disease control rate. The median progression‐free survival in patients with and without irAE was 301 and 63 days, respectively. The median overall survival (OS) in patients with and without irAE was 723 and 199 days, respectively. According to the timing of irAE onset, the OS was better in seven patients who developed irAE after 180 days than in nine patients who developed irAE within 180 days. Although 16 patients (59%) experienced any grade irAE, including three (11%) with grade 3 or more irAE, there were no treatment‐related deaths. These results indicated that the development of irAE may correlate with improved survival in patients with MM treated with nivolumab monotherapy. Further studies are necessary to confirm these findings.