Contact states with femoral cortical bone and periprosthetic bone mineral density changes differ between traditional and newly introduced fully hydroxyapatite-coated stems.

Aims: The aim of this study was to compare the pattern of initial fixation and changes in periprosthetic bone mineral density (BMD) between patients who underwent total hip arthroplasty (THA) using a traditional fully hydroxyapatite (HA)-coated stem (T-HA group) and those with a newly introduced fully HA-coated stem (N-HA group). Methods: The study included 36 patients with T-HA stems and 30 with N-HA stems. Dual-energy X-ray absorptiometry was used to measure the change in periprosthetic BMD, one and two years postoperatively. The 3D contact between the stem and femoral cortical bone was evaluated using a density-mapping system, and clinical assessment, including patient-reported outcome measurements, was recorded. Results: There were significantly larger contact areas in Gruen zones 3, 5, and 6 in the N-HA group than in the T-HA group. At two years postoperatively, there was a significant decrease in BMD around the proximal-medial femur (zone 6) in the N-HA group and a significant increase in the T-HA group. BMD changes in both groups correlated with BMI or preoperative lumbar BMD rather than with the extent of contact with the femoral cortical bone. Conclusion: The N-HA-coated stem showed a significantly larger contact area, indicating a distal fixation pattern, compared with the traditional fully HA-coated stem. The T-HA-coated stem showed better preservation of periprosthetic BMD, two years postoperatively. Surgeons should consider these patterns of fixation and differences in BMD when selecting fully HA-coated stems for THA, to improve the long-term outcomes.

A novel imageless accelerometer-based navigation system improves acetabular cup placement accuracy during total hip arthroplasty in the lateral decubitus position.

INTRODUCTION: The accuracy of acetabular cup placement using conventional portable imageless navigation systems in total hip arthroplasty (THA) in the lateral decubitus position remains challenging. Several novel portable imageless navigation systems have been developed recently to improve cup placement accuracy in THA. This study compared the accuracy of acetabular cup placement using a conventional accelerometer-based portable navigation (c-APN) system and a novel accelerometer-based portable navigation (n-APN) system during THA in the lateral decubitus position. MATERIALS AND METHODS: This retrospective cohort study compared 45 THAs using the c-APN and 45 THAs using the n-APN system. The primary outcomes were the absolute errors between the intraoperative and postoperative values of acetabular cup radiographic inclination and anteversion angles and the percentage of cases with absolute errors within 5°. Intraoperative values were shown on navigation systems, and postoperative measurements were conducted using computed tomography images. RESULTS: The median absolute errors of the cup inclination angles were significantly smaller in the n-APN group than in the c-APN group (3.9° [interquartile range 2.2°-6.0°] versus 2.2° [interquartile range 1.0°-3.3°]; P = 0.002). Additionally, the median absolute errors of the cup anteversion angles were significantly smaller in the n-APN group than in the c-APN group (4.4° [interquartile range 2.4°-6.5°] versus 1.9° [interquartile range 0.8°-2.7°]; P < 0.001). Significant differences were observed in the percentage of cases with absolute errors within 5° of inclination (c-APN group 67% versus n-APN group 84%; P = 0.049) and anteversion angles (c-APN group 62% versus n-APN group 91%; P = 0.001). CONCLUSIONS: The n-APN system improved the accuracy of the cup placement compared to the c-APN system for THA in the lateral decubitus position.

Is bone remodelling around fully hydroxyapatite-coated and tapered-wedge stems related to the stem fixation pattern?

PURPOSE: This study aimed to compare bone mineral density (BMD) changes around the femoral component after total hip arthroplasty (THA) in a fully hydroxyapatite-coated stem (CORAIL) and in a tapered-wedge stem (Taperloc complete) and identify predictors of BMD changes. METHODS: This retrospective study compared 43 hips in the CORAIL group and 40 hips in the Taperloc group. The relative changes in BMD at 2 years after THA measured using dual-energy X-ray absorptiometry and the three-dimensional quantified contact states of the stem with the femoral cortical bone were assessed. Predictors of the relative change in the BMD around the proximal part of the stem were examined using multiple regression analysis. RESULTS: The decrease in BMD in Gruen zone 7 was significantly less in the CORAIL group than in the Taperloc group (P = 0.02). In the CORAIL group, the contact area in any zone was not a significant predictor of the relative changes in BMD. The contact area between the Taperloc stem and the femoral cortical bone in zones 2 and 6 was a positive predictor of the relative changes in BMD in zones 1 (P = 0.02 and P = 0.04, respectively) and 2 (P = 0.008 and P = 0.004, respectively). CONCLUSION: The CORAIL stem suppressed the postoperative BMD loss around the stem, irrespective of the contact state. The Taperloc complete stem required contact with the proximal femoral metaphysis to suppress the postoperative BMD loss around the stem.

Stem alignment with short tapered-wedge cementless stems affects bone mineral density continuously for at least 5 years after primary total hip arthroplasty.

AIM: This study aimed to assess the relationship between the three-dimensional (3D) alignment of short tapered-wedge cementless stems and bone mineral density (BMD) changes in patients followed up for 5 years after total hip arthroplasty (THA). METHODS: We retrospectively analysed the hips of 52 patients who underwent THA using short tapered-wedge cementless stems at our institution from 2013 to 2016 with complete 5-year follow-up data. We evaluated the relationship between stem alignment, measured using a 3D-templating software, and BMD changes in the 7 Gruen zones. RESULTS: After 1 year, significant negative correlations between varus insertion and a decrease in BMD in zone 7 and between flexed insertion and decreases in BMD in zones 3 and 4 were noted. After 5 years, significant negative correlations between varus insertion and a decrease in BMD in zone 7 and between flexed insertion and decreases in BMD zones 2, 3, and 4 were observed. With increased amounts of varus/flexion stem alignment, the amount of BMD loss decreased. There was no correlation between anteverted stem insertion and changes in BMD levels. CONCLUSIONS: Our data showed that stem alignment affects BMD based on 5-year follow-up data after surgery. Careful observation is necessary, especially when using short tapered-wedge cementless stems, as stem alignment may affect changes in BMD levels more than 5 years after surgery.

The modification of bone cut angle and joint line obliquity did not change the tibiofemoral kinematics and stability of knee joint after total knee arthroplasty.

INTRODUCTION: Previous reports using cadaveric knees and musculoskeletal computer simulation have shown that kinematically aligned (KA) total knee arthroplasty (TKA) provides more natural and physiological tibiofemoral kinematic patterns than mechanically aligned (MA) TKA. These reports suggested that the modification of joint line obliquity improve the knee kinematics. This study aimed to determine whether joint line obliquity change the intraoperative tibiofemoral kinematics in TKA candidates with knee osteoarthritis. METHODS: Thirty consecutive knees with varus osteoarthritis that underwent TKA using a navigation system were evaluated. Two types of trial components were prepared: (1) MA TKA model: component trial in which articulating surface was parallel to the bone cut surface (2) KA TKA model: the femoral component trial, which mimicked the KA TKA method of Dossett et al. was designed 3° valgus and 3° internal rotation to the femoral bone cut surface, and the tibial component trial was designed 3° varus to the tibial bone cut surface. These two trials were set on the same knees during the operation, and the tibiofemoral rotational kinematics and varus-valgus laxity were measured from 0° to 120° of knee flexion using a navigation system. RESULTS: The joint gap was 20 ± 2 mm and 3° ± 1° varus in extension and 20 ± 2 mm and 3° ± 1°varus in flexion. The differences in femoral component rotation between KA TKA and MA TKA were not statistically significant for any knee flexion angle. The differences in varus-valgus laxity between KA TKA and MA TKA were also not statistically significant for any knee flexion angle. CONCLUSION: Although the degree of joint line obliquity varies widely in various KA TKA methods, this study, which mimicked the method of Dossett et al. showed that the modification of joint line obliquity did not change the tibiofemoral kinematics and stability of the knee joint in TKA candidates with knee osteoarthritis.

Safe Introduction of Hydroxychloroquine Focusing on Early Intolerance Due to Adverse Drug Reactions in Patients with Systemic Lupus Erythematosus.

Objective This study explored the predictors of hydroxychloroquine intolerance and propose appropriate methods to initiate hydroxychloroquine in patients with systemic lupus erythematosus. Methods This retrospective study registered consecutive patients who were diagnosed with systemic lupus erythematosus and started treatment with hydroxychloroquine between 2015 and 2021. Any adverse events that required dose reduction or cessation of hydroxychloroquine, indicating intolerance to the drug, were recorded for up to 26 weeks after initiation of hydroxychloroquine. Results A total of 130 patients were included. Hydroxychloroquine intolerance due to adverse drug reactions was observed in 28 patients (21.5%), including gastrointestinal symptoms in 15 (11.5%) and cutaneous reactions in 7 (5.4%). Furthermore, the intolerance was observed more frequently in the maintenance group (patients treated daily with <20 mg prednisolone) than in the induction group (7.1% vs. 25.5%, p=0.04), and none of the patients in the induction group developed cutaneous reactions. The initial dose of hydroxychloroquine per ideal body weight was associated with hydroxychloroquine intolerance in a dose-dependent manner. Multivariable analyses revealed that the hydroxychloroquine dose per ideal body weight and higher levels of C4 predicted hydroxychloroquine intolerance. In particular, C4 levels were positively correlated with cutaneous reactions, whereas the dose of prednisolone was negatively correlated with gastrointestinal reactions. Conclusion Low-dose hydroxychloroquine may be optimal for induction in patients with systemic lupus erythematosus who have high C4 levels or are taking low doses of steroids.

Cryoglobulinemic Vasculitis Associated with Monoclonal Gammopathy of Undetermined Significance Developed after Sustained Virologic Response of Hepatitis C.

A 72-year-old woman had a history of chronic hepatitis C virus (HCV) infection previously treated with interferon to achieve a sustained virologic response. Thereafter, she developed polyarthritis and purpura of the lower extremities as well as progressive renal dysfunction with hypertension and proteinuria that had occurred in the last three months. Laboratory investigations revealed seropositivity for cryoglobulin but negative findings for HCV RNA. She was ultimately diagnosed with cryoglobulinemic glomerulonephritis complicated by monoclonal gammopathy of undetermined significance (MGUS) based on the pathological findings of the kidney and bone marrow, indicating that MGUS-induced cryoglobulinemic vasculitis may occur even after HCV elimination.

Portal Vein Thrombosis as a Cause of Undetermined Thrombocytopenia with Liver Dysfunction in a Patient with Eosinophilic Granulomatosis with Polyangiitis.

We herein report a 20-year-old woman who developed eosinophilic granulomatosis with polyangiitis (EGPA) and portal vein thrombosis (PVT). EGPA was diagnosed based on the patient's history of asthma, hypereosinophilia, and mononeuritis complex. Thrombocytopenia and liver dysfunction were observed, necessitating contrast-enhanced computed tomography (CECT), which revealed PVT. Her symptoms soon improved with glucocorticoids and anticoagulation therapy. As patients with EGPA often suffer from asthma, they can be hesitant to undergo CECT. However, if patients with EGPA show uncertain thrombocytopenia with liver dysfunction, a further evaluation using CECT is warranted to detect PVT.

Appearance of anti-MDA5 antibody-positive dermatomyositis after COVID-19 vaccination.

The direct causes of dermatomyositis, a common autoimmune disease, have not yet been accurately identified, but several studies have linked this condition to various patient-associated and environmental factors, such as viral infections and area of residence. In the present report, we describe our experience with a patient presenting with anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis, which developed after vaccination against coronavirus disease 2019 (COVID-19). This patient was simultaneously diagnosed with anti-glutamic acid decarboxylase antibody-positive slowly progressive insulin-dependent diabetes (SPIDDM); her human leucocyte antigen test revealed that she expressed the DRB1*04:05 allele. This is important as this genotype is known to increase susceptibility to both anti-MDA5 antibody-positive dermatomyositis and type I diabetes. To the best of our knowledge, this is the first case of dermatomyositis complicated by SPIDDM identified after COVID-19 vaccination against COVID-19 and presenting with an underlying susceptible genotype. The patient's genetic predisposition may also be important for the development of autoimmune disease after COVID-19 vaccination.

Fluorodeoxyglucose-positron emission tomography/computed tomography-positive ear lesions responsive to immunosuppressive therapy in a patient with otitis media with antineutrophil cytoplasmic antibody-associated vasculitis.

A 74-year-old woman presented with vertigo, left-beating nystagmus, and auditory disturbance 4 months prior, in whom a former physician suspected Meniere's disease. Her signs and symptoms mildly improved with a moderate dose of glucocorticoids, which was eventually tapered. Fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) was performed 12 days prior to routine examination. Remarkable FDG uptake was observed in the surrounding areas of the bilateral Eustachian tubes and left middle ear, which was only partially detected on magnetic resonance imaging. The patient also tested positive for myeloperoxidase-antineutrophil cytoplasmic antibody (ANCA). She was admitted to our hospital and diagnosed with otitis media with ANCA-associated vasculitis (OMAAV) based on the classification criteria. Four months after immunosuppressive therapy, the abnormal ear findings were not observed on follow-up FDG-PET/CT. The clinical course of this case suggests that FDG-PET/CT can detect occult ear involvement better than do other modalities in patients with OMAAV. In addition, FDG-PET/CT-positive ear lesions responded to immunosuppressive therapy. Therefore, FDG-PET/CT can help distinguish OMAAV from other ear diseases with non-inflammatory aetiologies and detect occult treatment-responsive OMAAV lesions in the clinical setting.

Delayed aortic injury after thoracic corrective osteotomy: a case report.

PURPOSE: To present a case of delayed aortic perforation due to a nondisplaced fracture of the 9th rib after vertebral osteotomy for degenerative kyphoscoliosis in patients with osteoporosis. METHODS: A 78-year-old female patient with osteoporosis had undergone T9-iliac correction surgery for degenerative kyphoscoliosis. After 2 years, the patient underwent T10 pedicle subtraction osteotomy for a T10 vertebral fracture and progression of kyphosis. Postoperatively, the patient had been doing well for 3 weeks; however, just before the day of discharge, she died following a cardiopulmonary arrest. An autopsy was performed with the consent of her family. RESULTS: Autopsy revealed a large amount of blood and a clot in the left thoracic cavity. Aortic perforation was found just in front of a nondisplaced fracture of the left 9th rib. CONCLUSION: This report describes a new critical complication after spinal correction surgery. Even without pedicle screw malposition, aortic injuries can happen to patients with osteoporosis after corrective osteotomy for degenerative kyphoscoliosis due to positional change of aorta and fragility of the ribs. The spine surgeon should be aware of this type of complication, and rib fractures around the aorta after vertebral osteotomy should not be neglected even when there is no displacement.

Accuracy of tibial component placement in unicompartmental knee arthroplasty performed using an accelerometer-based portable navigation system.

PURPOSE: There is a need for new devices to improve the accuracy of implantation in unicompartmental knee arthroplasties (UKAs). The accelerometer-based portable navigation system is expected to improve this accuracy. This study aimed to compare the accuracy of UKAs performed by the portable navigation system with that of the conventional method, and to investigate whether the portable navigation system can complement the surgeon's experience. METHODS: The study comprised of 80 Oxford UKAs. Knees were divided into two groups based on the method of tibial osteotomy: the conventional group (37 UKAs performed by an experienced surgeon using the extra-medullary guide) and the portable navigation group (43 UKAs performed by 2 unaccustomed surgeons using the navigation system). The absolute error from the target angle on the coronal and sagittal plane was measured on whole lower leg X-ray. The incidence of outliers (> 3°) was compared between the groups using Fisher's exact probability test. RESULTS: The incidences of outliers on the coronal plane were 41.0% (15 of 37 knees) in the conventional group and 9.3% (4 of 43 knees) in the portable navigation group (p < 0.0001). The incidences of outliers on the sagittal plane were 13.5% (5 of 37 knees) in the conventional group and 14.0% (6 of 43 knees) in the portable navigation group (p = 0.3772). CONCLUSION: This is the first report on the usefulness of an accelerometer-based portable navigation system in UKA. The use of this system improves the accuracy of implantation of the tibial component beyond the experience of the surgeon. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

Molecular Epidemiological Survey of Leptospira Infection of Wild Rodents in the Urban Settlement of Cambodia.

INTRODUCTION: Leptospirosis remains a major public health threat in Cambodia. In this study, we aimed at facilitating the development of preventive strategies against leptospirosis in Cambodia by conducting molecular epidemiological surveys of Leptospira infection among wild rodents. MATERIALS AND METHODS: One hundred sixty-three wild rodents were captured in the capital Phnom Penh and surrounding areas, and their kidneys and bladders were collected for analysis. Identification of wild rodent species was determined by using the cytochrome c oxidase I gene. TaqMan PCR of the flagellin B gene (flaB) was performed to detect Leptospira, and species of the isolates were identified by flaB sequencing analysis. RESULTS: The species and respective number of rodents collected were as follows: Rattus norvegicus, 80 (49.1%); Rattus argentiventer, 53 (32.5%); Rattus exulans, 6 (3.7%); Rattus indica, 15 (9.2%); Maxomys surifer, 3 (1.8%); and Rattus sp., 6 (3.7%). Leptospira was detected in 20 out of the 163 rodents (12.3%) and was categorized as either Leptospira interrogans or Leptospira noguchii. R. norvegicus had the highest prevalence of Leptospira (17.5%), and R. argentiventer and Rattus sp. showed infection rates of 9.4% and 16.7%, respectively. CONCLUSIONS: Based on these results, wild rodents living in urban areas of Cambodia were found to be important reservoirs of highly virulent Leptospira. The flaB sequence results of our study provided information regarding the prevalence of Leptospira species, which was dependent on the rodent species. This study is the first study on leptospirosis in wild rodents in the urban areas of Cambodia, where there is limited information on leptospirosis.