Retrospective study comparing the accuracies of handheld infrared stereo camera and augmented reality-based navigation systems for total hip arthroplasty.

BACKGROUND: The use of portable navigation systems (PNS) in total hip arthroplasty (THA) has become increasingly prevalent, with second-generation PNS (sPNS) demonstrating superior accuracy in the lateral decubitus position compared to first-generation PNS. However, few studies have compared different types of sPNS. This study retrospectively compares the accuracy and clinical outcomes of two different types of sPNS instruments in patients undergoing THA. METHODS: A total of 158 eligible patients who underwent THA at a single institution between 2019 and 2022 were enrolled in the study, including 89 who used an accelerometer-based PNS with handheld infrared stereo cameras in the Naviswiss group (group N) and 69 who used an augmented reality (AR)-based PNS in the AR-Hip group (group A). Accuracy error, navigation error, clinical outcomes, and preparation time were compared between the two groups. RESULTS: Accuracy errors for Inclination were comparable between group N (3.5° ± 3.0°) and group A (3.5° ± 3.1°) (p = 0.92). Accuracy errors for anteversion were comparable between group N (4.1° ± 3.1°) and group A (4.5° ± 4.0°) (p = 0.57). The navigation errors for inclination (group N: 2.9° ± 2.7°, group A: 3.0° ± 3.2°) and anteversion (group N: 4.3° ± 3.5°, group A: 4.3° ± 4.1°) were comparable between the groups (p = 0.86 and 0.94, respectively). The preparation time was shorter in group A than in group N (p = 0.036). There were no significant differences in operative time (p = 0.255), intraoperative blood loss (p = 0.387), or complications (p = 0.248) between the two groups. CONCLUSION: An Accelerometer-based PNS using handheld infrared stereo cameras and AR-based PNS provide similar accuracy during THA in the lateral decubitus position, with a mean error of 3°-4° for both inclination and anteversion, though the AR-based PNS required a shorter preparation time.

Descriptive analysis of incidence and risk factors for short intramedullary nail breakage in femoral intertrochanteric fractures: a multicenter (TRON group) retrospective study.

BACKGROUND: The incidence of hip fractures is increasing. Femoral intertrochanteric fractures make up 50% of hip fractures and are treated by intramedullary nails. Implant breakage is a recognized complication that can have rare and serious implications. This study aimed to investigate implant breakage rates after surgical treatment for femoral intertrochanteric fractures. METHODS: This was a retrospective multicenter analysis. All 1854 patients who underwent surgical treatment for femoral intertrochanteric fractures were selected from 12 hospitals (TRON group) between 2016 and 2020. Exclusion criteria included implants other than those specified and follow-up periods less than three months. Demographic data, surgical details, and radiographic assessments were collected from medical records and X-ray evaluations. RESULTS: Among the 983 study patients, consisting of 245 males (24.9%) and 738 females (75.1%), the implant breakage rate was 0.31%, with three confirmed cases. The average age was 83.9 years. The mean follow-up period was 640.9 days. Two cases were linked to ASULOCK implants, and one to an OLSII implant. Statistical analysis showed a significantly higher incidence of ASULOCK implant breakage (p < 0.001). In the two cases of ASULOCK implant breakage and one case of OLSII implant breakage, breakage in all three implants occurred at the anti-rotation screws. CONCLUSIONS: There were no implant breakages of the main body of the implants; all breakages occurred in the additional anti-rotation screw. The necessity of the anti-rotation screw will require further discussion. These results can potentially inform clinical decisions and guide further research in preventing implant breakage.

Early surgery within 48 hours of admission for hip fracture did not improve 1-year mortality in Japan: a single-institution cohort study.

INTRODUCTION: Early surgery for hip fracture, within 48 hours of hospital admission, is effective in reducing mortality. However, the average preoperative waiting time for hip fractures in Japan is 4.5 days and the 1-year mortality rate after a hip fracture is 10% in Japan. This study aimed to investigate whether early surgery, within 48 hours, could reduce the 1-year mortality rate in patients with hip fractures in Japan. METHODS: This cohort study involved 402 consecutive patients with hip fractures who underwent surgical treatment between January 2013 and September 2019. The exclusion criteria were an age of <60 years and in-hospital injury. A total of 389 patients were included in this study. The patients were divided into two groups: those who underwent early surgery within 48 hours of admission (early group) and those who di not undergo early surgery (delayed group). We compared patient characteristics and treatment outcomes between the 2 groups. RESULTS: A comparison of patient characteristics revealed that the early group had lower hemoglobin levels (P=0.046), lower C-reactive protein levels (P = 0.031), lower numbers of patients with weekend hospitalization, lower numbers of patients with a history of using medications that may cause bleeding (P < 0.01), and who received general anaesthesia (P < 0.01). However, there were no significant differences with regard to the other variables between the 2 groups. A treatment outcome analysis showed that the early group had shorter waiting times for surgery (P < 0.01) and shorter stays in acute-care wards (P < 0.01). However there were no differences in the total hospital stay, Barthel index at discharge, home discharge rates, in-hospital mortality rates, and 1-year mortality. CONCLUSION: Our findings indicate that early surgery did not reduce the 1-year mortality rate in older patients with hip fractures in Japan.

Factors related to collapse progression in Japanese Investigation Committee classification type B osteonecrosis of the femoral head.

PURPOSE: This study aimed to identify factors related to collapse progression in Japanese Investigation Committee classification type B osteonecrosis of the femoral head (ONFH) and to identify patients who would benefit from surgical treatment. METHODS: This study included 41 patients (56 hips) with type B ONFH with a minimum follow-up of three years. Based on a ≥ 3 mm collapse progression in ONFH, we categorised patients into two groups: collapse progression and no collapse progression. Sagittal and coronal computed tomography images were used to measure the necrotic region relative to the intact femoral head diameter. The ratios of the necrotic regions of transverse and vertical diameter in coronal and sagittal images are defined as mediolateral transverse and mediolateral vertical, anteroposterior transverse and anteroposterior vertical, respectively. Demographic data and these imaging findings were compared between the two groups. We established a cut-off value for predicting collapse progression through receiver operating characteristic analysis and determined survival rates. RESULTS: Type B ONFH had a 17.8% collapse progression rate. The mediolateral transverse, mediolateral vertical, anteroposterior transverse, and anteroposterior vertical were significantly higher in the collapse progression group (P < 0.01). Mediolateral transverse was an independent risk factor of collapse progression (hazard ratio, 1.27; 95% confidence interval, 1.03-1.57; P = 0.03), with an optimal cut-off of 45.6%. The 5-year survival rates with collapse progression as the endpoints were 57.0 and 94.9% in the mediolateral transverse of ≥ 45.6 and < 45.6%, respectively. CONCLUSION: A mediolateral transverse of ≥ 45.6% predicts collapse progression in patients with type B ONFH.

Low and high body mass index and lower numbers of screws in the articular segment are risk factors for non-union of distal humeral fractures in the elderly: A multi-center retrospective study (TRON study).

Background: Distal humerus fracture in the elderly is a challenging fracture for orthopedic surgeons. Non-union is one of the serious complications of distal humerus fracture after surgery. This retrospective multicenter study aimed to estimate the incidence of distal humeral non-union after open reduction and internal fixation, determine factors related to non-union, and compare the postoperative results of cases with non-union to cases with the union. Methods: Among 423 patients diagnosed with distal humeral fracture and who were treated by surgical therapy in 2010-2020 from our database called TRON. Only 190 subjects met the inclusion criteria. We performed a logistic regression analysis with the presence of non-union as the response variable to examine risk factors. We compare the Mayo Elbow Performance Scores of cases with non-union to cases with the union. Results: Non-union occurred after surgery in 15 patients (7.9%). The logistic regression analysis showed that body mass index<20 kg/m2 and ≥25 kg/m2, and ≤3 screws in the articular segment were significant explanatory factors for non-union (odds ratio 10.4 and 47.8, respectively). The Mayo Elbow Performance Scores were significantly worse in patients with non-union. Discussion: Low and high body mass index and three or fewer screws in the articular segment might be risk factors for non-union of distal humerus fracture in the elderly. Non-union is associated with poor clinical outcomes.

Comparison of conjoined tendon-preserving posterior approach and conventional posterolateral approach in hemiarthroplasty for femoral neck fracture in the elderly: A multicenter (TRON group) retrospective study.

BACKGROUND: Femoral neck fractures (FNF) are one of the most common traumatic injuries in the elderly. The conjoined tendon-preserving posterior (CPP) approach was developed as a modification of the conventional posterolateral (PL) approach in hemiarthroplasty (HA) for displaced femoral neck fractures (FNF) to reduce postoperative dislocation. We hypothesized that the CPP approach would result in fewer dislocations and similar functional and radiographic outcomes compared to the PL approach. PATIENTS AND METHODS: This was a retrospective multicenter (TRON group) study. We evaluated the rate of complications, and functional and radiographic outcomes for patients aged >65 years who underwent HA via the PL approach or the CPP approach from 2017 to 2019 and followed up for at least 24 months. To adjust for baseline differences between the groups, a propensity score-matching algorithm was used in a 1:1 ratio. RESULTS: We identified 135 patients who underwent HA via the PL approach and 135 patients via the CPP approach. The mean follow-up period was 32.4 ± 14.0 months. The incidence of dislocation was 6 in 135 patients (4.4%) in the PL group and 0 in 135 patients (0%) in the CPP group, and there was significant difference (p = 0.04). Operation time was equivalent between the two groups (73.1 ± 30.4 vs. 71.8 ± 30.0 min; p = 0.72). The rate of varus insertion of stems in the PL group lower than that in the CPP group (19.3% vs. 33.3%; p = 0.01). Postoperative Parker's mobility score was similar between the two groups at 12 months follow-up (6.17 vs. 6.27; p = 0.81). CONCLUSION: The CPP approach showed a significantly lower dislocation rate, similar functional outcome and more varus stem insertions compared with the PL approach in this retrospective study.

Risk factors of periprosthetic joint infection after hemiarthroplasty for displaced femoral neck fracture in the elderly: Analysis of 1619 cases in the multicenter database.

PURPOSE: This multicenter retrospective study focuses on understanding the incidence, causative bacteria, and risk factors for Periprosthetic Joint Infection (PJI) following hemiarthroplasty in elderly patients with displaced femoral neck fractures (FNF). METHODS: From 2016 to 2020, 1,619 patients were diagnosed with displaced FNFs and treated surgically across 11 centers. After exclusions, 1,438 patients (399 men and 1,039 women) were included in the study, averaging 82.1 years in age and 20.2 kg/m² in BMI, observed over 25.7 months on average. Data on demographics, medical history, surgical details, and complications were described. RESULTS: PJI occurred in 20 of the 1438 patients (1.4%). The causative organism was methicillin-susceptible Staphylococcus aureus in 6 patients and methicillin-resistant S. aureus in 6 patients. In patients' backgrounds, the average age was slightly higher in the non-PJI group (82.1 years) compared to the PJI group (80.4 years). There was a higher percentage of males in the PJI group (45%) than in the non-PJI group (27.5%). Drug history showed that the prevalence of anticoagulant use in the PJI group was 25%. Peripheral vascular disease and diabetes mellitus were more prevalent in the PJI group. Most patients in both groups were independent in daily activities. The blood transfusion rate was significantly higher in the PJI group (50%) than in the non-PJI group (23.8%). Notably, the incidence of hematoma was higher in the PJI group (40%). CONCLUSION: This multicenter retrospective study demonstrates a low incidence (1.4%) of PJI in elderly patients undergoing hemiarthroplasty for FNF, primarily due to Staphylococcus aureus. Increased usage of antiplatelets and anticoagulants, as well as comorbidities related to atherosclerosis, like peripheral vascular disease and diabetes mellitus, were observed in patients with PJI. Additionally, these patients experienced higher rates of blood transfusion and postoperative hematomas, highlighting the need for careful management. It should be noted, however, that this finding is a conclusion limited by study design issues, including the retrospective design, small PJI sample size, and variability in treatment approaches.

Obesity Is Associated with Asymptomatic Vertebral Fractures: A Yakumo Study.

(1) Background: Patients with primary vertebral fracture (VF) are at high risk of re-fracture and mortality. However, approximately two-thirds of patients with VFs receive minimal clinical attention. (2) Methods: The current study aimed to investigate the factors associated with asymptomatic VFs in middle-aged and elderly individuals who underwent resident health examinations. (3) Results: The current study included 217 participants aged > 50 years. VFs were diagnosed based on lateral radiographic images using Genant's semiquantitative (SQ) method. The participants were divided into non-VF (N; SQ grade 0) and asymptomatic VF (F; SQ grades 1-3) groups. Data on body composition, blood tests, quality of life measures, and radiographic parameters were assessed. A total of 195 participants were included in the N group (mean age, 64.8 ± 7.8 years), and 22 were in the F group (mean age, 66.1 ± 7.9 years). The F group had a significantly higher body mass index (BMI), body fat percentage (BF%), and proportion of patients with knee osteoarthritis (KOA) than the N group. The F group had a significantly higher knee joint pain visual analog scale (VAS) score and painDETECT score than the N group. Logistic regression analysis showed that BF% was associated with asymptomatic VFs. (4) Conclusions: Middle-aged and elderly individuals with asymptomatic VF presented with high BMIs, BF%, and incidence of KOA.

Fracture of the patella involving inferior pole is associated with postoperative patella baja - A retrospective multicenter study.

BACKGROUND: The patella fracture involving of inferior pole fractures (IPF) may be associated with patella baja, However, the clinical impact of this condition remains unclear. This study aims to clarify 1) the incidence of patella baja following patellar fracture surgery, 2) the associated clinical outcomes with and without the presence of patella baja, and 3) the potential correlation between the detection of IPF on CT and the occurrence of patella baja. METHODS: We conducted a retrospective multicenter study involving 251 patients who underwent surgical treatment for patellar fractures. Patients were divided into the patella baja (PB; n = 49) group and patella norma (PN; n = 202) group. Data collected included demographics, radiographic findings, surgical details, and postoperative complications. We compared these items between PB group and PN group. Logistic regression analyses were used to identify risk factors for patella baja. RESULTS: Immediately following surgery, 36 (14.3%) patients presented with patella baja which increased to 49 cases (19.5%) at six months postoperatively. There is no statistically significant difference in the demographics, surgical details, clinical outcomes and complication between PB group and PN group. While, in the radiographical assessment, the prevalence of IPF on CT scan in the patella baja group was significantly higher than that in the patella norma group. By logistic regression analysis, IPFP on CT was identified as an independent risk factor for patella baja. (odds ratio 2.11, 95% confidence interval: 1.03-4.33, p = 0.042). CONCLUSION: In patients with patellar fractures, the incidence of patella baja increased from 14.3% immediately post-surgery to 19.5% at the six-month check-up. No significant differences were observed in clinical outcomes between the patella baja group and the norma group. The patella fracture involving IPF on CT emerged as a predictive factor for patella baja.

A Longitudinal Study on the Effect of Exercise Habits on Locomotive Syndrome and Quality of Life during the Coronavirus Disease 2019 Pandemic.

During the COVID-19 pandemic, this study investigated the potential of exercise habits to improve quality of life (QOL) and prevent locomotive syndrome (LS) in residents of Yakumo-cho, Hokkaido, Japan. Participants from the 2018 health checkup were surveyed in February 2022, focusing on 200 respondents. These individuals were divided based on their 2018 exercise habits (at least 1 h per week): the exercise group (E group) and the non-exercise group (N group), further categorized in 2022 into the 2022E and 2022N groups. QOL was measured using the SF-36 (physical functioning, general health, physical role, physical pain, vitality, social functioning, emotional role, and mental health) and EuroQoL 5-dimension 5-level questionnaires (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression), and LS was assessed with the 25-question geriatric locomotive function scale. These showed no significant change in exercise habits from 2018 to 2022. In the non-LS group, the 2022E group had higher vitality and emotional role functioning scores compared to the 2022N group. For those with LS, the 2022E group reported less physical pain. Notably, the LS incidence was significantly lower in the 2022E group. This study concludes that consistent exercise habits positively impact QOL and reduce the LS risk, underscoring the importance of regular physical activity, especially during challenging times like a pandemic. These findings highlight the broader benefits of maintaining exercise routines for public health, particularly in periods of global health crises. Based on our findings, we recommend that people continue to exercise at least one hour per week to prevent LS.

Diaphyseal forearm fracture management in adolescent patients from 2011 to 2020: A multicenter study of surgery and regional anesthesia trends.

BACKGROUND: Diaphyseal forearm fractures are common traumatic injuries among children. There has been much debate on the use of intramedullary nailing (IMN) or plate fixation in the adolescent population (10-16 years of age). Furthermore, as ultrasound technology has advanced, the safety and efficacy of ultrasound-guided axillary brachial plexus block for children has dramatically improved. Therefore, anesthesia options for adolescent patients have increased in recent years. This study aimed to investigate recent surgical and regional anesthesia trends of diaphyseal forearm fractures in patients 10 to 16 years of age in Japan through a multicenter epidemiological survey from 2011 to 2020. METHODS: This retrospective, multicenter study included 226 pediatric patients with diaphyseal forearm fracture aged 10-16 years treated from January 2011 to December 2020. We divided the patients into four groups according to the period in which they were treated: early (2011-2013), middle (2014-2016), late (2017-2019), and COVID-19 (2020). Information from medical records was used to investigate the number of surgeries, types of anesthesia administered, and internal fixation methods used for diaphyseal forearm fracture in adolescent patients during each period. RESULTS: The number of surgeries was generally constant in each period but decreased during the COVID-19 period. In the early, middle, late, and COVID-19 periods, the percentages of surgeries performed under regional anesthesia were 67.7, 85.5, 87.0, and 100% respectively (p = 0.003). During the same periods, the percentages of patients receiving IMN were 41.5, 49.3, 58.0, and 66.7%, respectively (p = 0.033). CONCLUSION: The use of IMN and regional anesthesia to treat diaphyseal forearm fracture in patients 10 to 16 years of age steadily increased during the study period from 2011 to 2020. These results indicate that regional anesthesia is safe, effective, and well-tolerated by adolescent patients. The treatment strategy for diaphyseal forearm fractures in adolescents using regional anesthesia in combination with IMN worked well and was effective during COVID-19. Our evidence suggests this trend will continue. We anticipate that our findings can be extrapolated for upper extremity fractures in adolescent patients beyond the Tokai region of Japan where the study was based.

Prevalence and Treatment Rates of Osteoporosis Among Individuals with Rotator Cuff Tears.

BACKGROUND: The relationship between osteoporosis and rotator cuff tears has been reported previously. However, the treatment rate of osteoporosis in individuals with rotator cuff tear is still unknown. The aim of this study was to investigate the prevalence and treatment rate of osteoporosis in individuals with rotator cuff tears. METHODS: In this cross-sectional study, we enrolled 207 participants. Participants underwent comprehensive assessments, including shoulder ultrasonographic examinations and quantitative ultrasound (QUS) measurements for bone status evaluation. Osteoporosis diagnosis was predicated on a calcaneus ultrasound bone densitometry, and the cutoff value was set as a T score of -1.455, with reference to a previous report. RESULTS: 156 participants were classified as individuals without rotator cuff tears (group A), and 51 participants were classified as those with (group B). The mean age in group A was significantly lower than that in group B (63 ± 10 vs. 68 ± 9, respectively; p = 0.003). In terms of the T score examined by QUS, the mean T score in group A was significantly higher than that in group B (-1.4 ± 1.3 vs. -1.9 ± 1.6, respectively; p = 0.0412). The percentage of subjects with a T score of -1.455 or less in group B was 60.8% (31/51). The proportion of subjects with a T score of -1.455 or less undergoing osteoporosis treatment was 14.5% (12/83) in group A and 12.9% (4/27) in group B, showing no significant difference. CONCLUSIONS: Participants with a rotator cuff tear had relatively high prevalence of osteoporosis. Among those with both a rotator cuff tear and osteoporosis, the proportion receiving osteoporosis treatment was l2.9%, a very low rate.

Is spinopelvic compensation associated with unstable gait?: Analysis using whole spine X-rays and a two-point accelerometer during gait in healthy adults.

BACKGROUND: Pelvic incidence (PI)-lumbar lordosis (LL) mismatch has a significant destabilizing effect on the center of gravity sway in the static standing position. However, the association between spinopelvic alignment and balance during gait in healthy volunteers is poorly understood. RESEARCH QUESTION: The degree of PI-LL mismatch and trunk anterior tilt in the static standing posture influences dynamic balance during gait. METHODS: In this study, 131 healthy volunteers were divided into two groups: harmonious group (PI - LL ≤ 10°; n = 91) and unharmonious group (PI - LL > 10°; n = 40). A two-point accelerometer system was used for gait analysis; accelerometers were attached to the pelvis and upper trunk to measure acceleration in the forward-backward, right-left, and vertical directions so that sagittal (front-back) deviation width, coronal (right-left) width, and vertical width and their ratios were calculated. Measurements were compared between the two groups, and correlations between alignment and accelerometer data were examined. RESULTS: The harmonious group showed a negative correlation between pelvic sagittal width and PI - LL, pelvic tilt (PT), and sagittal vertical axis (SVA) (correlation coefficient ρ = -0.42, -0.38, and -0.4, respectively), and a positive correlation between sagittal ratio and PI - LL (ρ = 0.35). The unharmonious group showed a positive correlation between pelvic sagittal width and PI and PT (ρ = 0.43 and 0.33, respectively) and between sagittal ratio and SVA (ρ = 0.32). The unharmonious group showed a positive correlation between upper trunk sagittal width and PI - LL and PT (ρ = 0.38 and 0.36, respectively). SIGNIFICANCE: The association between spinal alignment and gait parameters differs depending on the presence or absence of PI-LL mismatch. The degree of pelvic compensation and trunk anterior tilt during static standing were associated with unstable gait balance.

Association between advanced glycation end-products and fall risk in older adults: The Yakumo Study.

AIM: Advanced glycation end-products (AGEs) are irreversibly and heterogeneously formed compounds during the non-enzymatic modification of macromolecules, such as proteins. Aging and lifestyle habits, such as high-fat and high-protein diets, and smoking, promote AGEs accumulation. This study aimed to investigate the relationship between fall risk and AGEs in community-dwelling older adults. METHODS: This cross-sectional study included patients from the 2022 Yakumo Study who were evaluated for fall risk index 5-items version, locomotive syndrome stage and AGEs. AGEs were evaluated using Skin autofluorescence (SAF) measured by the AGE reader (DiagnOptics Technologies BV, Groningen, the Netherlands). We divided the participants into two groups according to the presence or absence of fall risk (fall risk index 5-items version ≥6 or not), and investigated the factors associated with fall risk. RESULTS: The fall risk group had a higher age and SAF, and a higher proportion of locomotive syndrome stage >2 than the without fall risk group in patients aged ≥65 years (P < 0.01). The multivariate logistic regression analysis after adjustment of age, sex and body mass index showed that locomotive syndrome stage ≥2 and SAF were independent associators of fall risk in older adults (odds ratio 3.26, P < 0.01, odds ratio 2.96, P < 0.05, respectively). The optimal cutoff value of the SAF for fall risk was 2.4 (area under the curve 0.631; 95% CI 0.53-0.733; sensitivity 0.415; specificity 0.814; P < 0.05). CONCLUSION: The accumulation of AGEs in skin tissues can be used to screen for fall risk comprehensively. Geriatr Gerontol Int 2024; 24: 517-522.

Does Preoperative Manual Reduction (Omoto Technique) Affect Surgical Outcomes for Calcaneal Fractures? A Multicenter (TRON Group) Retrospective Study.

The Omoto technique is a well-known method that is commonly used for noninvasive manual repair of calcaneal fractures. However, there have been no detailed studies on its clinical outcomes in preoperative closed reduction for surgical cases. This multicenter retrospective study aimed to compare the clinical and radiographic outcomes of calcaneal fractures treated with and without the preoperative Omoto technique, assessing its effectiveness. We extracted 335 patients with calcaneal fracture who underwent surgery between 2015 and 2020 from our multicenter database, named TRON. We evaluated the clinical outcomes using the American Orthopedic Foot and Ankle Society (AOFAS) score, the Böhler angle (BA) for radiographic analysis, and noted any complications. We divided the patients into those managed with the Omoto technique (group O) and those managed without the Omoto technique (group N). Patients were matched by age, sex, and fracture type, resulting in 43 patients per group. The use of the Omoto technique at the time of injury significantly improved the Böhler angle (BA). Furthermore, there were no significant differences in AOFAS, postoperative complications, or BA values at the final follow-up. In conclusion, our study demonstrates that the Omoto technique, when used preoperatively for calcaneal fractures, does not negatively impact the outcomes of subsequent surgical treatments. For patients who prefer to avoid surgery, the Omoto technique can be an effective initial intervention. Additionally, our findings suggest that the Omoto technique may facilitate less invasive surgical options in certain cases.

External validation of a deep learning model for predicting bone mineral density on chest radiographs.

We developed a new model for predicting bone mineral density on chest radiographs and externally validated it using images captured at facilities other than the development environment. The model performed well and showed potential for clinical use. PURPOSE: In this study, we performed external validation (EV) of a developed deep learning model for predicting bone mineral density (BMD) of femoral neck on chest radiographs to verify the usefulness of this model in clinical practice. METHODS: This study included patients who visited any of the collaborating facilities from 2010 to 2020 and underwent chest radiography and dual-energy X-ray absorptiometry (DXA) at the femoral neck in the year before and after their visit. A total of 50,114 chest radiographs were obtained, and BMD was measured using DXA. We developed the model with 47,150 images from 17 facilities and performed EV with 2914 images from three other facilities (EV dataset). We trained the deep learning model via ensemble learning based on chest radiographs, age, and sex to predict BMD using regression. The outcomes were the correlation of the predicted BMD and measured BMD with diagnoses of osteoporosis and osteopenia using the T-score estimated from the predicted BMD. RESULTS: The mean BMD was 0.64±0.14 g/cm2 in the EV dataset. The BMD predicted by the model averaged 0.61±0.08 g/cm2, with a correlation coefficient of 0.68 (p<0.01) when compared with the BMD measured using DXA. The accuracy, sensitivity, and specificity of the model were 79.0%, 96.6%, and 34.1% for T-score < -1 and 79.7%, 77.1%, and 80.4% for T-score ≤ -2.5, respectively. CONCLUSION: Our model, which was externally validated using data obtained at facilities other than the development environment, predicted BMD of femoral neck on chest radiographs. The model performed well and showed potential for clinical use.

Does Early and Late Weight Bearing Have an Effect on the Results of Elderly Tibial Plateau Fractures with Internal Fixation?: A Multicenter (TRON Group) Study.

Introduction: There is still no consensus on the length of the non-bearing period required for tibial plateau fractures (TPFs) treated surgically. Several studies showed that full weight bearing immediately postoperatively does not affect fixation or cause joint collapse in patients with TPF. While there are concerns about weight bearing in the elderly due to fragile bone quality, their physical disability often makes it difficult to carry out activities of daily life when weight bearing is not allowed. The purpose of this study was to assess differences in clinical and radiographic outcomes between an early weight-bearing (EWB) group and a non-weight-bearing (NWB) group following TPF in elderly patients. Material and Methods: We extracted the data of 432 patients who suffered TPF from January 2011 to December 2020 from a database which is named TRON. We excluded patients with insufficient follow-up postoperatively, AO type A/C fracture, age < 60 years old, multiple trauma, and those lost to follow-up. Finally, 91 patients were eligible. EWB group patients were encouraged to perform partial weight-bearing walking at ≤ 4 weeks after surgery, whereas NWB group patients were not allowed weight bearing for > 4 weeks after surgery. Baseline intergroup differences were adjusted for by matching age, sex, body mass index, smoking history, and injury mechanism. We compared Knee Society Score (KSS), timing of full weight bearing, and X-ray findings including step-off, tibia plateau angle, plateau slope, and condylar widening in the X-rays between the two groups. Results: There were no significant statistical differences between the EWB group and NWB group after matching. The mean follow-up period was 28.0 (range 12-73) months. All cases did not require reoperation or additional procedures. The median KSS at 12 months or at the last follow up postoperatively was 100 (77-100) vs. 95 (75-100) points (P = 0.33). There were no differences in fracture-related infection rates or wound dehiscence. In the radiological evaluation of EWB and NWB, the correction loss of condylar widening was only significantly greater for EWB compared to NWB. Conclusions: We found that early weight bearing could contribute to increased condylar widening. While our short-term follow-up didn't reveal any significant clinical differences, this highlights the need for long-term follow-up to comprehensively understand the implications of these radiographic changes.

Long-term oral meclozine administration improves survival rate and spinal canal stenosis during postnatal growth in a mouse model of achondroplasia in both sexes.

Achondroplasia (ACH) is a skeletal dysplasia characterized by short-limbed short stature caused by the gain-of-function mutations in the fibroblast growth factor receptor 3 (FGFR3) gene. Activated FGFR3, which is a negative regulator of bone elongation, impairs the growth of long bones and the spinal arch by inhibiting chondrocyte proliferation and differentiation. Most patients with ACH have spinal canal stenosis in addition to short stature. Meclozine has been found to inhibit FGFR3 via drug repurposing. A 10-d treatment with meclozine promoted long-bone growth in a mouse model of ACH (Fgfr3ach mice). This study aimed to evaluate the effects of long-term meclozine administration on promoting bone growth and the spinal canal in Fgfr3ach mice. Meclozine (2 mg/kg/d) was orally administered to Fgfr3ach mice for 5 d per wk from the age of 7 d to 56 d. Meclozine (2 mg/kg/d) significantly reduced the rate of death or paralysis and improved the length of the body, cranium, and long bones in male and female Fgfr3ach mice. Micro-computed tomography analysis revealed that meclozine ameliorated kyphotic deformities and trabecular parameters, including BMD, bone volume/tissue volume, trabecular thickness, and trabecular number at distal femur of Fgfr3ach mice in both sexes. Histological analyses revealed that the hypertrophic zone in the growth plate was restored in Fgfr3ach mice following meclozine treatment, suggesting upregulation of endochondral ossification. Skeletal preparations demonstrated that meclozine restored the spinal canal diameter in Fgfr3ach mice in addition to improving the length of each bone. The 2 mg/kg/d dose of meclozine reduced the rate of spinal paralysis caused by spinal canal stenosis, maintained the growth plate structure, and recovered the bone quality and growth of axial and appendicular skeletons of Fgfr3ach mice in both sexes. Long-term meclozine administration has the potential to ameliorate spinal paralysis and bone growth in patients with ACH.

Association of mid-thigh quadriceps muscle quality with postoperative outcomes in patients with hip osteoarthritis undergoing total hip arthroplasty: a retrospective cohort study.

PURPOSE: Muscle quality is more important than muscle mass for assessing physical function. Computed tomography (CT) is used to evaluate intramuscular fatty infiltration. The mid-thigh quadriceps CT attenuation values (CTV) expressed in Hounsfield units (HU) negatively correlate with physical function. Patients with hip osteoarthritis (HOA) have lower extremity muscle atrophy, including decreased cross-sectional area (CSA), CTV, and muscle strength. Using preoperative CT images, we investigated the association between mid-thigh quadriceps CSA, CTV, and postoperative outcomes in patients with HOA. METHODS: This study included 62 patients who had unilateral HOA (62 hips) and underwent total hip arthroplasty (THA). We investigated the association between preoperative and postoperative Japanese Orthopaedic Association (JOA) hip scores, 12-item Short Form survey (SF-12), mid-thigh quadriceps CSA, and CTV. RESULTS: The mean age was 64.7 ± 10.1 years, with 15 men (24.2%), and the mean body mass index was 24.3 ± 4.3 kg/m2. Secondary HOA was present in 79.0% of patients. The mean CSA and CTV of the mid-thigh quadriceps on the operative side were 38.8 ± 9.8 cm2 and 40.3 ± 7.8 HU, respectively. Multiple regression analyses adjusted for age and sex showed that preoperative mid-thigh quadriceps CSA was not associated with preoperative and postoperative JOA hip scores or SF-12. The preoperative mid-thigh quadriceps CTV was associated with the postoperative JOA hip score in the gait ability domain and SF-12 in the physical component summary domain. CONCLUSION: Preoperative muscle quality is associated with postoperative outcomes in patients who have HOA regardless of age and sex.

Comparing short vs. intermediate and long nails in elderly patients with unstable multifragmental femoral trochanteric fractures (AO type A2): Multicenter (TRON group) retrospective study.

BACKGROUND: Unstable femoral trochanteric fractures (FTFs), especially Arbeitsgemeinschaft für Osteosynthesefragen/ the Orthopedic Trauma Association (AO/OTA) 31-A2 fractures, which are multifragment fractures, occur in elderly individuals with osteoporosis and are associated with high mortality and complication rates due to prolonged immobilization. Longer nails (LNs) were developed to obtain superior fracture site stabilization in unstable FTFs. We hypothesized that the postoperative outcomes of elderly patients with unstable FTFs treated with LNs would be superior to those of patients treated with short nails (SNs), with fewer complications. METHODS: This multicenter retrospective study aimed to compare the outcomes of SNs versus LNs in elderly patients with unstable FTFs. From the Trauma Research Group of our university (TRON) database, 1854 trochanteric fractures treated between January 2016 and December 2020 were extracted. A total of 174 patients>65 years of age with AO/OTA 31-A2 fractures were included in the present study. They were divided into the SN group and the LN group and matched for age and sex. Parameters such as operative time, blood loss, survival rate, Parker Mobility Score (PMS), and numerical rating scale (NRS) for pain, complications, and radiographic findings were analyzed. RESULTS: Both groups included 67 patients with an average age of 87.32 years. The LN group had a longer operative time (76.52 min vs. 51.61 min, P < 0.001) and more blood loss (106.79 mL vs. 49.98 mL, P = 0.014) in comparison to the SN group. However, the 1-year survival rate, PMS, and NRS for pain did not differ to a statistically significant extent between the groups. The rates of complications, including screw cutout, nonunion, implant breakage, osteonecrosis of the femoral head, and surgical site infections, were comparable. The radiographic findings, including the nail/canal ratio, progression of varus, and sliding distance, were also similar. CONCLUSION: Although LNs are associated with longer operative times and increased blood loss, the overall outcomes and complication rates are comparable to those of SNs in elderly patients with AO/OTA 31-A2 type unstable FTFs. The use of LNs did not confer any distinct advantages for this specific type of fracture.