Histomorphometric analysis of patients with femoral neck fracture and 25-hydroxyvitamin D deficiency: a cross-sectional study.

INTRODUCTION: Vitamin D deficiency causes osteoporosis, bone mineralization disorders, and osteomalacia. Osteomalacia is diagnosed using blood biochemical tests, clinical symptoms, and imaging; however, accurate detection of mineralization disorders requires tissue observation. We investigated the prevalence of bone mineralization disorders and their relationship with serum 25-hydroxyvitamin D (25OHD) levels in patients with untreated osteoporosis with femoral neck fractures. MATERIALS AND METHODS: A non-demineralized specimen was prepared from the femoral head removed during surgery in 65 patients. Bone histomorphometry of cancerous bone in the femoral head center was conducted. Osteoid volume per bone volume (OV/BV) and osteoid thickness (O.Th) were measured as indicators of mineralization disorder. RESULTS: The mean serum 25OHD level (11.9 ± 5.7 ng/mL) was in the deficiency range (< 12 ng/mL). There were no clinically diagnosed cases of osteomalacia (OV/BV > 10% and O.Th > 12.5 µm); however, one case of mineralization disorder, considered histologically pre-osteomalacia (OV/BV > 5% and O.Th < 12.5 µm), was observed (OB/BV, 17.6%; O.Th, 12.3 µm). Excluding this case, those with severe (25OHD < 12 ng/mL, at risk of osteomalacia; n = 39) and non-severe deficiency (25OHD ≥ 12 ng/mL; n = 25) did not significantly differ in OV/BV (%; 0.77 ± 0.54 vs. 0.69 ± 0.38, p = 0.484) or O.Th (µm; 5.32 ± 1.04 vs. 5.13 ± 0.78, p = 0.410). Further, 25OHD and OV/BV were not significantly correlated (R = - 0.124, p = 0.327). CONCLUSION: This is the first study in the twenty-first century to examine serum 25OHD concentrations and bone mineralization disorders in Japanese patients with osteoporosis. The results indicate that vitamin D deficiency does not necessarily cause bone mineralization disorders and rarely leads to osteomalacia.

A Multidisciplinary Approach to Hip Fractures: Evaluating Outcomes on Mortality and Secondary Hip Fractures.

Fracture liaison services (FLS) have been introduced in Japan and several other countries to reduce medical complications and secondary fractures. We aimed to evaluate the effects of the implementation of an FLS approach on patient outcomes during hospitalization at our hospital and over a 2-year follow-up post-injury. This retrospective cohort study included patients ≥ 60 years admitted to our hospital for hip fragility fractures between October 1, 2016, and July 31, 2020. Patient groups were defined as those treated before (control group, n=238) and after (FLS group, n=196) establishment of the FLS protocol at our institution. The two groups were compared in terms of time to surgery, length of hospital stay, and the incidence of complications after admission, including secondary hip fracture and mortality rates. The follow-up period was 24 months. FLS focuses on early surgery within 48 h of injury and assessing osteoporosis treatment before injury to guide post-discharge anti-osteoporosis medication. FLS reduced the length of hospital stay (p<0.001) and the prevalence of complications after admission (p<0.001), particularly cardiovascular disease, and it increased adherence to anti-osteoporosis medication. These FLS effects resulted in lower secondary hip fracture and mortality rates at 12 and 24 months post-injury. FLS for fragility hip fractures can improve patient outcomes during hospitalization and over a 2-year follow-up period.

Hip Fractures in Elderly Individuals Did Not Decrease during the Coronavirus Disease 2019 Pandemic: Insights from the 2015 and 2020 Niigata Prefecture Fragility Hip Fracture Surveys.

Background and Objectives: The incidence of osteoporotic hip fractures in Niigata Prefecture, Japan, has been studied approximately every 5 years since 1985. In 2020, as in previous surveys, a prefecture-wide survey was initiated as planned; however, the global outbreak of the coronavirus disease 2019 (COVID-19) began simultaneously. This study aimed to compare the results of the 2015 and 2020 Niigata Prefecture Fragility Hip Fracture Surveys to determine whether the COVID-19 pandemic affected the occurrence and treatment of proximal femoral fractures throughout Niigata Prefecture. Materials and Methods: In this study, data from the 2015 and 2020 Niigata Prefecture Fragility Hip Fracture Surveys were used. Data were obtained from registration forms returned by hospitals and clinics in Niigata Prefecture for patients living therein who were diagnosed with osteoporotic hip fractures over a 1-year period in 2015 and 2020. Results: In Niigata Prefecture, the total annual number of fractures increased from 3181 in 2015 to 3369 in 2020, whereas the age-adjusted fracture rate decreased. Regarding the location of the fractures, the proportion of outdoor fractures was lower than that of indoor fractures. The proportion of outdoor fractures decreased over the year as a whole, but in particular, the proportion of outdoor fractures decreased significantly under the issued emergency declarations. The most common reasons for delayed surgery related to COVID-19 were "waiting for PCR results" and "quarantine for fever," accounting for approximately 1.9% of all causes. Conclusions: In Niigata Prefecture, Japan, the effect of the COVID-19 pandemic on the number and rate of fractures was minuscule. The proportion of indoor fractures to outdoor fractures increased during the emergency declaration period. Considering that the number of fragility fractures remains the same during an infectious disease pandemic such as COVID-19, it is necessary to ensure that healthcare resources are available to deal with them.

Increased incidence among the very elderly in the 2020 Niigata Prefecture Osteoporotic Hip Fracture Study.

INTRODUCTION: A 2015 study showed a decreasing trend in the incidence of osteoporotic hip fractures in Niigata Prefecture, Japan, which had been increasing. This study aimed to investigate the incidence of osteoporotic hip fractures in 2020, determine the long-term change in the incidence of hip fractures from 1985 to 2020, and assess whether the decline in fracture incidence since 2010 has continued. MATERIALS AND METHODS: We obtained data from the registration forms submitted by hospitals and clinics of patients who lived in Niigata Prefecture and were diagnosed with osteoporotic hip fracture through a survey conducted from January 1, 2020 to December 31, 2020. RESULTS: In 2020, 3,369 hip fractures were recorded in Niigata Prefecture. Although the overall incidence of age-specific hip fractures decreased, it increased in patients aged ≥ 90 years, regardless of sex. The proportion of patients receiving anti-osteoporosis drugs prior to hip fracture increased from 7.6% in 2004 to 17.3% in 2020. Notably, surgical treatment should be performed as early as possible, and the preoperative waiting time was 2.9 days, which was mainly due to holidays. CONCLUSION: The incidence of hip fractures in Niigata Prefecture has gradually increased over the past 35 years, with an increasing change observed in the very elderly recently in 2020. Although the treatment of osteoporotic hip fractures in Niigata Prefecture is adequate, improvements may include increasing the rate of adoption of osteoporosis treatment further and decreasing the number of days of preoperative waiting.

Determining factors that maintain physical function or increase frailty using the Kihon checklist among community-dwelling older adults: a six-year longitudinal study in Agano, Japan.

BACKGROUND: A significant increase in the older adult population in Japan will significantly increase healthcare costs. This study aimed to examine the risk factors contributing to robustness transitioning to frailty in older residents. METHODS: Participants were aged 70 in 2016 and 76 in 2022. Participants were evaluated using the Kihon Checklist (KCL). RESULTS: Participants for this longitudinal study included 444 older persons who completed the KCL surveys in 2016 and 2022. The follow-up rate was 80.6%; therefore, 358 participants were included in the analysis. The median KCL score increased significantly from 2 to 2016 to 3 in 2022 (p < 0.001). The prevalence of robustness significantly decreased from 60.9 to 48.6% (p = 0.042). In a stepwise logistic regression analysis, robustness was independently associated with regular continuous walks for 15 min and a body mass index of above 18.5%. The following variables were associated with the transition to prefrailty: experiencing a fall in the past year and not going out at least once a week. For the transition to frailty, the variables were turned to family or friends for advice, experienced a fall in the past year, and felt helpless in the last two weeks. The independent factor for the transition from prefrailty to frailty was having a BMI of less than 18.5. In contrast, the independent factor for improving from frailty to robustness or prefrailty was going out at least once a week. CONCLUSIONS: We recommend maintaining continuous walking for more than 15 min, maintaining a BMI of at least 18.5, and going out more than once a week to improve being house-bounded and depressive mood, not only to prevent the transition to prefrailty or frailty but also to improve frailty.

Relationship between the Hip Abductor Muscles and Abduction Strength in Patients with Hip Osteoarthritis.

This study aimed to determine which muscle the gluteus maximus, gluteus medius, gluteus minimus (Gmin), or tensor fasciae latae (TFL) contributes most to hip abduction strength and to identify effective sites for cross-sectional area (CSA) Gmin and TFL measurement in hip osteoarthritis (OAhip) patients. Twenty-eight patients with OAhip were included. The muscle CSA and volume were determined using magnetic resonance imaging. Peak isometric strength was determined using hand-held dynamometry. Muscle volumes were normalized to the total muscle volume of hip abductors. Multiple regression analysis was performed. The difference between the CSA of Gmin and TFL was calculated, and correlations with volume and muscle strength were determined. Gmin volume was related to abductor muscle strength (p=0.042). The peak CSA of the Gmin correlated with muscle volume and strength. The CSA of the TFL correlated with volume, with no difference between the CSA of the most protruding part of the lesser trochanter and peak CSA. Gmin volume was strongly related to abductor muscle strength. Peak CSA is a useful parameter for assessing the CSA of the Gmin among patients with OAhip. The CSA of the TFL should be measured at the most protruding part of the lesser trochanter.

Analysis of Phase Angle and Balance and Gait Functions in Pre-Frail Individuals: A Cross-Sectional Observational Study.

We measured the muscle mass and phase angle of each body part to evaluate the relationship between balance and gait functions in individuals with a pre-frailty status. This cross-sectional observational study determined the skeletal muscle mass-to-body weight ratio and phase angles of 21 control (robust) and 29 pre-frail subjects. Their Brief-Balance Evaluation Systems Test, Timed Up-and-Go (TUG) test, Life-Space Assessment, and Modified Fall Efficacy Scale scores plus the relationship between muscle mass, phase angle, and motor function were evaluated. In the pre-frailty group (three males, 26 females, aged 75.58±7.60 years), significant correlations were noted between the Brief-Balance Evaluation Systems Test score and lower-limb (r=0.614) and wholebody (r=0.557) phase angles, and between the TUG test score and lower-limb muscle mass-to-body weight ratio (r=-0.616), lower-limb phase angle (r=-0.616), and whole-body phase angle (r=-0.527). Evaluating the phase angle of the lower extremities of pre-frail patients and intervening accordingly may help clinicians maintain and improve these patients' balance and gait functions.

Low back pain significantly influences locomotive syndrome in older people: Evaluation using the 3-stage categories.

BACKGROUND: The Japanese Orthopaedic Association (JOA) introduced the concept of locomotive syndrome (LS), which indicates a decline in mobility function by musculoskeletal disorders with new 3-staged category. Additionally, sarcopenia indicates a decline in the quantity and/or quality of skeletal muscle. However, the relationship between low back pain (LBP) and LS or sarcopenia in older people has not been sufficiently understood. This study aimed to investigate the association between them through a cross-sectional locomotorium survey. METHODS: A total of 302 participants were drawn from the aquatic exercise participants in a rural area of Japan. The body mass index, body fat percentage, skeletal muscle mass index (SMI), spinal inclination angle (SIA), grip strength, timed up-and-go test (TUG), and maximum stride of the participants were measured. LBP and LBP-related quality of life (QOL) were evaluated using the Oswestry Disability Index (ODI), visual analogue scale (VAS) of LBP, and the Short-Form 8 (SF-8). Associations between the investigating parameters and sarcopenia or LS were analyzed. RESULTS: There were no significant differences in the findings except grip strength between the non-sarcopenia and sarcopenia groups. However, the LS group showed significantly larger SIA, higher ODI, higher VAS of LBP, lower physical component score (PCS) of the SF-8, longer time in TUG, and lower value in maximum stride than the non-LS group. In addition, the ODI and PCS of the SF-8 significantly deteriorated as the LS stage progressed, and the GLFS-25 score was significantly correlated with ODI (r = 0.706, p < 0.001) and PCS (r = -0.643, p < 0.001) scores. CONCLUSIONS: LBP, LBP-related QOL, and physical performance were found to be significantly associated with LS, not sarcopenia, with LBP-related QOL and physical function being closely correlated with 3-stage categories of LS. Thus, these results suggested that LBP is a key factor for LS prevalence.

Accuracy of ZedView, the Software for Three-Dimensional Measurement and Preoperative Planning: A Basic Study.

Background and Objectives: In the field of orthopedic surgery, novel techniques of three-dimensional shape modeling using two-dimensional tomographic images are used for bone-shape measurements, preoperative planning in joint-replacement surgery, and postoperative evaluation. ZedView® (three-dimensional measurement instrument and preoperative-planning software) had previously been developed. Our group is also using ZedView® for preoperative planning and postoperative evaluation for more accurate implant placement and osteotomy. This study aimed to evaluate the measurement error in this software in comparison to a three-dimensional measuring instrument (3DMI) using human bones. Materials and Methods: The study was conducted using three bones from cadavers: the pelvic bone, femur, and tibia. Three markers were attached to each bone. Study 1: The bones with markers were fixed on the 3DMI. For each bone, the coordinates of the center point of the markers were measured, and the distances and angles between these three points were calculated and defined as "true values." Study 2: The posterior surface of the femur was placed face down on the 3DMI, and the distances from the table to the center of each marker were measured and defined as "true values." In each study, the same bone was imaged using computed tomography, measured with this software, and the measurement error from the corresponding "true values" was calculated. Results: Study 1: The mean diameter of the same marker using the 3DMI was 23.951 ± 0.055 mm. Comparisons between measurements using the 3DMI and this software revealed that the mean error in length was <0.3 mm, and the error in angle was <0.25°. Study 2: In the bones adjusted to the retrocondylar plane with the 3DMI and this software, the average error in the distance from the planes to each marker was 0.43 (0.32-0.58) mm. Conclusion: This surgical planning software could measure the distance and angle between the centers of the markers with high accuracy; therefore, this is very useful for pre- and postoperative evaluation.

Passive ankle motion and calf massage without anticoagulation therapy after total hip arthroplasty: A retrospective study.

BACKGROUND: It has been previously reported that manual calf massage and passive ankle motion after total hip arthroplasty could reduce the incidence of venous thromboembolism. However, a combination of chemical and mechanical prophylaxes was employed. In this study, we aimed to examine the effect of mechanical prevention without pharmacological antithrombotic intervention. METHODS: Of the 313 patients who underwent unilateral primary total hip arthroplasty and received passive ankle motion and calf massage postoperatively at our hospital between January 2015 and December 2019, 261 (58 men, 203 women; mean age 62.1 years) were included in this retrospective study. Pharmacological anticoagulation therapy was administered in 176 patients (combination group); 137 patients only underwent calf massage and passive ankle motion without anticoagulation therapy (single group). The study outcomes were operation time, the incidence of deep vein thrombosis, pulmonary thromboembolism, intraoperative bleeding, estimated actual blood loss, blood transfusion, and major bleeding. RESULTS: No significant differences were found in sex, age, side, platelet counts, activated partial thromboplastin time, prothrombin time, prothrombin time - International Normalized Ratio, intraoperative blood loss, estimated blood loss, and operation time. Moreover, the incidence of deep vein thrombosis, pulmonary thromboembolism, and intraoperative bleeding was not significantly different between the groups (deep vein thrombosis 4.0% vs. 6.3%, p = 0.244; pulmonary thromboembolism 0.7% vs. 0%, p = 0.548; and intraoperative bleeding 394 ± 173.6 ml vs. 365.4 ± 168.5 ml, p = 0.550). However, estimated actual blood loss and postoperative bleeding differed between the groups (eABL 996.6 ± 348.3 ml vs. 858.5 ± 269.6 ml, p = 0.003; postoperative bleeding 601.8 ± 330.0 ml vs. 492.1 ± 277.1 ml, p = 0.016), and both increased in the combination group. No major bleeding was noted in the two groups. CONCLUSION: Postoperative anticoagulant therapy does not have to be routinely used if mechanical prophylaxis is performed in patients without deep vein thrombosis before total hip arthroplasty.

Accuracy of Acetabular Cup Implantation, as a Function of Body Mass Index and Soft-tissue Thickness, with a Mechanical Intraoperative Support Device: A Retrospective Observational Study.

HipCOMPASS, a mechanical intraoperative support device used in total hip arthroplasty (THA), improves the cup-alignment accuracy. However, the alignment accuracy achieved by HipCOMPASS has not been specifically examined in obese patients. In this study, we retrospectively evaluated the relation between alignment accuracy and several obesity-related parameters in 448 consecutive patients who underwent primary THA using HipCOMPASS. We used computed tomography (CT) to measure the preoperative soft-tissue thickness of the anterior-superior iliac spine (ASIS) and pubic symphysis and the differences between preoperative and postoperative cup angle based on the cup-alignment error. We found significant correlations between the absolute value of radiographic anteversion difference and body mass index (r = 0.205), ASIS thickness (r = 0.419), and pubic symphysis thickness (r = 0.434). The absolute value of radiographic inclination difference was significantly correlated with ASIS (r = 0.257) and pubic symphysis thickness (r = 0.202). The receiver operating characteristic curve showed a pubic symphysis thickness of 37.2 mm for a ≥ 5° implantation error in both radiographic inclination and anteversion simultaneously. The cup-alignment error for HipCOMPASS was large in patients whose pubic symphysis thickness was ≥ 37.2 mm on preoperative CT. Our results indicate that methods other than HipCOMPASS, including computed tomography-based navigation systems, might be preferable in obese patients.

Multidisciplinary Approach to Reduce Postoperative Complications and Improve the Activity of Patients with Hip Fracture: A 24-month Follow-up Survey.

Multidisciplinary approaches such as fracture liaison services (FLS) have been introduced in some countries to reduce medical complications and secondary fractures in patients with fragility hip fracture. We aimed to investigate outcomes in patients with fragility hip fracture following the introduction of FLS. Patients > 50 years old who experienced fragility hip fractures between January 1, 2015 and December 31, 2017 were enrolled, and divided into a control group (without FLS; 94 patients) and FLS group (373 patients). We found that the time from injury to surgery decreased significantly from 2.42 to 1.83 days (p = 0.003), the proportion of patients who underwent surgery within 36 h of injury increased significantly (p = 0.014), and the number of cases with complications after admission decreased significantly (p = 0.004) in the FLS group. Patients with a Barthel index ≥ 80 were more common in the FLS than the control group at 6 , 12, and 24 months following injury (p = 0.046 , 0.018, and 0.048, respectively). Multiple logistic regression analysis revealed the factors associated with postoperative complications and death within 12 or 24 months after injury. Our results indicate that FLS contributed to earlier recovery, rehabilitation following surgery and rehabilitation of medical complications following admission; improved patient activity; and decreased secondary hip fractures.

Appropriate sites for the measurement of the cross-sectional area of the gluteus maximus and the gluteus medius muscles in patients with hip osteoarthritis.

PURPOSE: To evaluate the relationship between the volume, cross-sectional area, and peak isometric muscle strength of the gluteus maximus and gluteus medius muscles in patients with hip osteoarthritis, and to use this information to identify effective sites for measurement of the cross-sectional area of these muscles. METHODS: Twenty-four patients with hip osteoarthritis were included. The muscle cross-sectional area and volume were calculated from magnetic resonance images. The cross-sectional area was calculated at three levels: the inferior point of the sacroiliac joint, just above the femoral head, and at the greatest muscle diameter. Peak isometric strength was assessed using hand-held dynamometry, using the extension and external rotation for the gluteus maximus and abduction and internal rotation for the gluteus medius. Measured outcomes were compared between the two muscles, and the association between muscle volume, cross-sectional area, and peak isometric muscle strength was evaluated using Pearson's correlation. RESULTS: Volume was correlated with the cross-sectional area in the gluteus maximus (r ≥ 0.707) and with the cross-sectional area (r ≥ 0.637) and peak isometric strength (r ≥ 0.477) in the gluteus medius. There was no difference between the cross-sectional area measured at the greatest muscle diameter and just above the femoral head (p = 0.503) for the gluteus maximus and at the inferior point of the sacroiliac joint (p = 0.651) for the gluteus medius. CONCLUSION: The cross-sectional area, when used to calculate the muscle volume, should be evaluated just above the femoral head for the gluteus maximus and at the inferior point of the sacroiliac joint for the gluteus medius.

Three-dimensional Evaluation of Abnormal Gait in Patients with Hip Osteoarthritis.

Indexes for objectively evaluating abnormal gait in hip osteoarthritis (OA) patients and determining effective interventions are unclear. We analyzed the abnormal gait of hip OA patients by focusing on movements of the trunk and pelvis to establish an effective evaluation index for each direction of motion. We studied 28 patients with secondary hip OA due to developmental dysplasia of the hip and 16 controls. The trunk and pelvic movements during gait were measured in the medial-lateral (x), vertical (y), and back-and-forth (z) directions by a triaxial angular accelerometer. Gait speed, steps, step length, muscle strength, range of motion, and timed up-and-go (TUG) test performance were measured. We determined the correlations between physical function and the index of abnormal gait in the hip OA patients. Movements other than trunk and pelvic motions in the y-direction indicated abnormal gait in the patients. Significant correlations were found between abnormal gait and range of motions (extension, internal rotation), TUG score, stride length, and steps. The TUG test, stride length and steps were important for evaluating abnormal gait in hip OA patients. Individual interventions for each movement direction are required.

Effects of administering different vehicles via single intratracheal instillation on responses in the lung and pleural cavity of Crl:CD(SD) rats.

Intratracheal instillation is the introduction of a substance directly into the trachea. Intratracheal instillation has been used to investigate the lung toxicity of several chemicals and requires the suspension or dissolution of test material in a vehicle for even dispersal throughout the lung. Importantly, the toxicities of vehicles used in intratracheal instillation studies are generally considered to be insignificant. Hence, evaluating the influence of different vehicles on the lung due to intratracheal instillation is crucial. We examined the toxic effects of pure water, saline, phosphate buffered saline (PBS), 0.5% Kolliphor® P188 (KP188), 0.1% Tween 20 in saline, and 1.0% BSA in PBS. These vehicles were administered to male Crl:CD(SD) rats by a single intratracheal instillation. On day 3, broncho-alveolar lavage fluid (BALF) from the right lung was collected and processed for cell counting and biochemical analysis, while the left lung was used for histopathological examination. Accumulation of alveolar macrophages was observed in all vehicle-treated groups but was minimal in the group administered saline, somewhat higher in the groups administered pure water, PBS, 0.1% Tween 20, and 1% BSA, and notably higher in the group administered 0.5% KP188. The results from BALF analysis indicated that intratracheal instillation of 0.5% KP188 also induced alveolar damage. Additionally, administering pure water did not appear to cause tissue damage. Eosinophil infiltration in the interstitial regions was histopathologically observed. Altogether, the results of this study are helpful for the selection of appropriate vehicles for use in intratracheal instillation studies.

Incidence of four major types of osteoporotic fragility fractures among elderly individuals in Sado, Japan, in 2015.

The aim of this study was to survey the incidence of osteoporotic fragility fractures, which include vertebral, hip, distal radius, and proximal humerus fractures, in patients ≥ 50 years of age, from 2004 to 2015, in Sado City, Japan. We examined temporal changes in the incidence of these fractures from 2010 through 2015. The incidence of vertebral (p < 0.001) and radius fractures (p = 0.001) was lower in 2015 than in 2010, with only the incidence of hip fracture (p = 0.013) being lower in 2015 than in 2004. With regard to age-specific incidences, there was a sharp increase in vertebral and hip fractures among the segment of the population 70-89 years old, with no remarkable change in the incidence of radial and humeral fractures. Pre-existing vertebral fractures were identified in 69.6% of patients with a hip fracture, 35.6% of patients with a distal radius fracture, and 55% of patients with a humeral fracture. Among patients with pre-existing vertebral fractures, 42.5% had a single fracture, whereas 57.5% had 2 or more fractures. The proportion of patients on anti-osteoporotic agents before the occurrence of fractures increased to 14.5% in 2015, compared to 4% in 2004 and 7.6% in 2010. We speculate that the increase in the use of anti-osteoporotic agents is the main reason for the declining incidence of fractures. Therefore, considering the sharp increase in hip and vertebral fractures among individuals in their mid-1970s and older, judicious use of anti-osteoporotic agents among these individuals could be useful for lowering the occurrence of these fractures.

Carcinogenicity of intermediate frequency magnetic field in Tg.rasH2 mice.

Although the likelihood of exposure to leaking intermediate frequency magnetic fields (MFs) from electronic devices, such as induction-heating and wireless power transfer systems, has increased, biological data assessing the health risks associated with human exposure remain insufficient. We examined the carcinogenicity of a 20 kHz MF, a typical frequency produced by induction-heating cookers, using a transgenic rasH2 mouse model. Twenty-five male and female CByB6F1-Tg(HRAS)2Jic mice were exposed to a 0.20 mT, 20 kHz MF (22 h/day) or sham-exposed for 26 weeks. As a positive control, 10 male and female rasH2 mice from the same batch were administered a single intraperitoneal injection of 75 mg/kg N-methyl-N-nitrosourea. A blinded histopathological evaluation was performed, and the same experiments were conducted twice, independently, to confirm the reproducibility of the results. Histopathological examination revealed that spontaneous neoplastic lesions, such as splenic hemangiosarcomas and gastric squamous cell papillomas, were less (1-3 per group) in the MF- and sham-exposed groups. The frequency of the neoplastic lesions was not significantly different between the groups. Eight to ten mice in each positive-control group exhibited malignant lymphoma. The outcomes were consistent between duplicated experiments, which indicates lack of carcinogenicity of 20 kHz MF in the rasH2 mouse model. Bioelectromagnetics. © 2019 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.

Tibiofemoral rotation is related to differences in the lateral femoral condyle configuration in both normal subjects and women with hip dysplasia: a three-dimensional analysis.

BACKGROUND: We assessed the morphological differences in the knee joint related to knee rotation angle in patients with hip dysplasia. These results may explain the anatomy of the knee in patients with hip dysplasia and aid in planning knee surgery. METHODS: We enrolled 73 women (146 legs, 35.6 ± 9.0 years) with bilateral hip dysplasia and 45 healthy women (90 legs, 49.0 ± 18.9 years) without lumbago, knee symptoms, or osteoarthritic findings of the knee or spine on plain radiographs. We examined the parameters affecting knee rotation angle, such as the condylar twist angle and femoral condyle measurements with a three-dimensional bone model using the correlation coefficients of each parameter. RESULTS: The condylar twist angle and the length of the posterior part of the lateral femoral condyle were statistically positively correlated with knee rotation angle in both the normal (condylar twist angle: r = 0.286, p = 0.007, posterolateral: r = 0.429, p < 0.001) and developmental dysplasia of the hip groups (condylar twist angle: r = 0.230, p = 0.033, posterolateral: r = 0.272, p = 0.005). Knee rotation angle had no statistical correlation with femoral neck anteversion in the developmental dysplasia of the hip group (r = 0.094, p = 0.264), but had a statistical correlation with femoral neck anteversion in the normal group (r = 0.243, p = 0.039). CONCLUSIONS: Knee joint morphology is affected by hip dysplasia. We found that the length of the posterior part of the lateral femoral condyle was significantly positively correlated with knee rotation angle in both the normal and developmental dysplasia of the hip groups, and this finding indicates that a greater posterolateral dimension was associated with a greater knee rotation angle. These morphological knee joint differences in patients with hip dysplasia may help determine the alignment of prostheses in total knee arthroplasty.

Accuracy of acetabular cup placement using CT-based navigation in total hip arthroplasty: Comparison between obese and non-obese patients.

BACKGROUND: In obese patients, malpositioning of the acetabular cup increases the risk of dislocation in total hip arthroplasty (THA). The aim of this study was to determine whether obesity affects the accuracy of acetabular cup positioning using a computed tomography (CT)-based navigation system. METHODS: We retrospectively evaluated 226 consecutive patients who underwent cementless primary THAs assisted by the CT-based hip navigation system. We divided the patients into three groups according to body mass index (BMI) and examined the difference between preoperative planning and postoperative implantation angles from CT data. RESULTS: There was no significant correlation between BMI and both inclination and anteversion differences (R = 0.028 and R = 0.045, respectively). There were no significant differences among the BMI < 25, 25 â‰¦ BMI < 30, and BMI â‰§ 30 groups (p value: 0.725, 0.934, respectively); between the BMI < 25 and BMI â‰§ 25 groups (p value: 0.542, 0.697, respectively); and between the BMI < 30 and BMI â‰§ 30 groups with regard to inclination and anteversion (p value: 0.859, 0.456, respectively). Moreover, similar findings were observed with regard to the distance between the preoperative planning and postoperative cup positioning for the transverse, anteroposterior, and craniocaudal axes of the pelvis. CONCLUSION: We found that the accuracy of acetabular cup placement using CT based-navigation in THA was not affected in obese patients. Therefore, THAs with a CT-based navigation system are considered useful in obese patients.

Investigation on the measurement sites of the cross-sectional areas of the gluteus maximus and gluteus medius.

PURPOSES: To verify the relationship between muscle volume and muscular strength of different cross-sectional areas (CSAs) of the gluteus maximus and medius, and to clarify the effective evaluation index. METHODS: Twenty healthy adults were enrolled in this cross-sectional study. Magnetic resonance images were evaluated, and CSAs of the gluteus maximus and medius were calculated. Calculation sites were the peak CSA, lowest end of the sacroiliac joint CSA, and just above the femoral head CSA. Muscle volume and muscular strength were measured. The correlation between muscular CSA, muscle volume, and muscular strength was verified using Pearson's correlation coefficient (p < 0.05). One-way analysis of variance and the Tukey-Kramer test were used to verify differences in each CSA (p < 0.05). RESULTS: A significantly positive correlation was found between muscular CSA, muscle volume, and muscular strength of both muscles (p < 0.05). For the gluteus maximus, the muscular CSA calculated just above the femoral head showed a significantly larger value than that calculated at the lowest end of the sacroiliac joint (p < 0.05). For the gluteus medius, the peak CSA and muscular CSA calculated at the lowest end of the sacroiliac joint were significantly larger than that calculated just above the femoral head (p < 0.05). CONCLUSIONS: The maximum CSA of the gluteus maximus was found just above the femoral head and that of the gluteus medius was near the lowest end of the sacroiliac joint; hence, CSAs should be calculated at these sites. The CSA reflected muscle volume and strength.