A class of chemical compounds enhances clustering of muscle nicotinic acetylcholine receptor in cultured myogenic cells.

Neuromuscular signal transmission is affected in various diseases including myasthenia gravis, congenital myasthenic syndromes, and sarcopenia. We used an ATF2-luciferase system to monitor the phosphorylation of MuSK in HEK293 cells introduced with MUSK and LRP4 cDNAs to find novel chemical compounds that enhanced agrin-mediated acetylcholine receptor (AChR) clustering. Four compounds with similar chemical structures carrying benzene rings and heterocyclic rings increased the luciferase activities 8- to 30-folds, and two of them showed continuously graded dose dependence. The effects were higher than that of disulfiram, a clinically available aldehyde dehydrogenase inhibitor, which we identified to be the most competent preapproved drug to enhance ATF2-luciferase activity in the same assay system. In C2C12 myotubes, all the compounds increased the area, intensity, length, and number of AChR clusters. Three of the four compounds increased the phosphorylation of MuSK, but not of Dok7, JNK. ERK, or p38. Monitoring cell toxicity using the neurite elongation of NSC34 neuronal cells as a surrogate marker showed that all the compounds had no effects on the neurite elongation up to 1 µM. Extensive docking simulation and binding structure prediction of the four compounds with all available human proteins using AutoDock Vina and DiffDock showed that the four compounds were unlikely to directly bind to MuSK or Dok7, and the exact target remained unknown. The identified compounds are expected to serve as a seed to develop a novel therapeutic agent to treat defective NMJ signal transmission.

Neurologic recovery following laminectomy and tumor resection of a pediatric cervical synovial osteochondromatosis causing paralysis.

PURPOSE: To report the surgical outcome of synovial osteochondromatosis, a rare tumor of the cervical spine, in a 6-year-old boy. METHODS: A 6-year-old boy presented with muscle weakness in the right deltoid (2) and biceps (4) during a manual muscle test. Magnetic resonance imaging showed a 3 × 2 × 1.5 cm mass within the spinal canal at the C4-6 level, compressing the cervical spinal cord from the right side. Computed tomography revealed hyperintense areas within the tumor and ballooning of the right C4-5 and C5-6 facet joints. RESULTS: After a biopsy confirmed the absence of malignancy, a gross total resection was performed. The pathological diagnosis of synovial osteochondromatosis was established. Postoperatively, muscle weakness improved fully in the manual muscle test, and there were no neurological findings after 3 months. However, the patient is under careful follow-up owing to the detection of a regrowth site within the right C4-5 and C5-6 intervertebral foramen 2 years postoperatively. CONCLUSIONS: Synovial osteochondromatosis of the cervical spine in children is rare, and this is the first report of its regrowth after surgery. Synovial osteochondromatosis should be included in the differential diagnosis of pediatric cervical spine tumors.

Analysis of spinopelvic parameters in adult patients with lumbosacral transitional vertebrae.

PURPOSE: Spinopelvic sagittal alignment is crucial for assessing balance and determining treatment efficacy in patients with adult spinal deformity (ASD). Only a limited number of reports have addressed spinopelvic parameters and lumbosacral transitional vertebrae (LSTV). Our primary objective was to study spinopelvic sagittal parameter changes in patients with LSTV. A secondary objective was to investigate clinical symptoms and quality of life (QOL) in patients with LSTV. METHODS: In this study, we investigated 371 participants who had undergone medical check-ups for the spine. LSTV was evaluated using Castellvi's classification, and patients were divided into LSTV+ (type II-IV, L5 vertebra articulated or fused with the sacrum) and LSTV- groups. After propensity score matching for demographic data, we analyzed spinopelvic parameters, sacroiliac joint degeneration, clinical symptoms, and QOL for these two participant groups. Oswestry Disability Index (ODI) scores and EQ-5D (EuroQol 5 dimensions) indices were compared between the two groups. RESULTS: Forty-four patients each were analyzed in the LSTV + and LSTV- groups. The LSTV + group had significantly greater pelvic incidence (52.1 ± 11.2 vs. 47.8 ± 10.0 degrees, P = 0.031) and shorter pelvic thickness (10.2 ± 0.9 vs. 10.7 ± 0.8 cm, P = 0.018) compared to the LSTV- group. The "Sitting" domain of ODI (1.1 ± 0.9 vs. 0.6 ± 0.7, P = 0.011) and "Pain/Discomfort" domain of EQ-5D (2.0 ± 0.8 vs. 1.6 ± 0.7, P = 0.005) were larger in the LSTV + group. CONCLUSION: There was a robust association between LSTV and pelvic sagittal parameters. Clinical symptoms also differed between the two groups in some domains. Surgeons should be aware of the relationship between LSTV assessment, radiographic parameters and clinical symptoms.

Does global spinal alignment affect the use of walking aids after multi-segment spinal fixation for patients with ASD? A multicenter retrospective study.

PURPOSE: This study aimed to clarify the relation between global spinal alignment and the necessity of walking aid use in patients with adult spinal deformity (ASD) and to investigate the impact of spinal fixation on mobility status after surgery. METHODS: In total, 456 older patients with ASD who had multi-segment spinal fixation surgery and were registered in a multi-center database were investigated. Patients under 60 years of age and those unable to walk preoperatively were excluded. Patients were classified by their mobility status into the independent, cane, and walker groups. Comparison analysis was conducted using radiographic spinopelvic parameters and the previously reported global spine balance (GSB) classification. In addition, preoperative and 2 years postoperative mobility statuses were investigated. RESULTS: Of 261 patients analyzed, 66 used walking aids (canes, 46; walkers, 20). Analysis of preoperative radiographical parameters showed increased pelvic incidence and pelvic incidence-lumbar lordosis mismatch in the walker group and increased sagittal vertebral axis in the cane and walker groups versus the independent group. Analysis of GSB classification showed a higher percentage of walker use in those with severe imbalance (grade 3) in the sagittal classification but not in the coronal classification. While postoperative radiographical improvements were noted, there was no significant difference in the use of walking aids before and 2 years after surgery (P = 0.085). CONCLUSION: A significant correlation was found between "sagittal" spinal imbalance and increased reliance on walking aids, particularly walkers. However, the limitation of improvement in postoperative mobility status suggested that multiple factors influence the mobility ability of elderly patients with ASD.

Preoperative low Hounsfield units in the lumbar spine are associated with postoperative mechanical complications in adult spinal deformity.

PURPOSE: To determine the most valid bone health parameter to predict mechanical complications (MCs) following surgery for adult spinal deformity (ASD). METHODS: This multicenter study retrospectively examined the records of patients who had undergone fusion of three or more motion segments, including the pelvis, with a minimum two-year follow-up period. Patients with moderate and severe global alignment and proportion scores were included in the study and divided into two groups: those who developed MCs and those who did not. Bone mineral density (BMD) of the lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry, and Hounsfield units (HUs) were measured in the lumbar spine on computed tomography. Radiographic parameters were evaluated preoperatively, immediately after surgery, and at final follow-up. RESULTS: Of 108 patients, 30 (27.8%) developed MCs, including 26 cases of proximal junctional kyphosis/failure, 2 of distal junctional failure, 6 of rod fracture, and 11 reoperations. HUs were significantly lower in patients who experienced MCs (113.7 ± 41.1) than in those who did not (137.0 ± 46.8; P = 0.02). BMD did not differ significantly between the two groups. The preoperative and two-year postoperative global tilt, as well as the immediately postoperative sagittal vertical axis, were significantly greater in patients who developed MCs than in those who did not (P = 0.02, P < 0.01, and P = 0.01, respectively). CONCLUSION: Patients who experienced MCs following surgery for ASD had lower HUs than those who did not. HUs may therefore be more useful than BMD for predicting MCs following surgery for ASD.

Longitudinal impact of multi-segment spinal fixation surgery on mobility status and clinical outcomes in adult spinal deformity: a multicenter retrospective study.

PURPOSE: To investigate changes in postoperative mobility status in patients with ASD, and the determining factors that influence these changes and their impact on clinical outcomes, including the rate of home discharge and long-term mobility. METHODS: A total of 299 patients with ASD who underwent multi-segment posterior spinal fusion were registered in a multi-center database were investigated. Patient mobility status was assessed using walking aids and classified into five levels (1: independent, 2: cane, 3: walker, 4: assisted, and 5: wheelchair) preoperatively, at discharge, and after 2 years. We determined improvements or declines in the patient's mobility based on changes in the classification levels. The analysis focused on the factors contributing to the deterioration of postoperative mobility. RESULTS: Two years postoperatively, 87% of patients maintained or improved mobility. However, 27% showed decreased mobility status at discharge, associated with a lower rate of home discharge (49% vs. 80% in the maintained mobility group) and limited improvement in mobility status (35% vs. 5%) after 2 years. Notably, postoperative increases in thoracic kyphosis (7.0 ± 12.1 vs. 2.0 ± 12.4°, p = 0.002) and lower lumbar lordosis (4.2 ± 13.1 vs. 1.8 ± 12.6°, p = 0.050) were substantial factors in mobility decline. CONCLUSION: Postoperative mobility often temporarily decreases but generally improves after 2 years. However, an overcorrection in sagittal alignment, evidenced by increased TK, could detrimentally affect patients' mobility status. Transient mobility decline associated with overcorrection may require further rehabilitation or hospitalization. Further studies are required to determine the biomechanical effects of surgical correction on mobility.

What Are the Sex-Based Differences of Acetabular Coverage Features in Hip Dysplasia?

BACKGROUND: Eccentric rotational acetabular osteotomy is performed to prevent osteoarthritis caused by developmental dysplasia of the hip (DDH). To achieve sufficient acetabular coverage, understanding the characteristics of acetabular coverage in DDH is necessary. However, the features of acetabular coverage in males with DDH remain unclear. We thought that the differences in acetabular coverage between females and males might be associated with the differences in pelvic morphology between the sexes. QUESTIONS/PURPOSES: (1) What are the differences in the acetabular coverage between females and males with DDH? (2) What are the differences in the rotations of the ilium and ischium between females and males with DDH? (3) What is the relationship between the rotation of the ilium and ischium and the acetabular coverage at each height in females and males with DDH? METHODS: Between 2016 and 2023, 114 patients (138 hips) underwent eccentric rotational acetabular osteotomy at our hospital. We excluded patients with Tönnis Grade 2 or higher, a lateral center-edge angle of 25º or more, and deformities of the pelvis or femur, resulting in 100 patients (122 hips) being included. For female patients (98 hips), the median (range) age was 40 years (10 to 58), and for the male patients (24 hips), it was 31 years (14 to 53). We used all patients' preoperative AP radiographs and CT data. The crossover sign, posterior wall sign, and pelvic width index were evaluated in AP radiographs. The rotation of the innominate bone in the axial plane was evaluated at two different heights, specifically at the slice passing through the anterior superior iliac spine and the slice through the pubic symphysis and ischial spine in CT data. Furthermore, we evaluated the anterior and posterior acetabular sector angles. Comparisons of variables related to innominate bone measurements and acetabular coverage measurements between females and males in each patient were performed. The correlations between pelvic morphology measurements and acetabular coverage were evaluated separately for females and males, and the results were subsequently compared to identify any sex-specific differences. For continuous variables, we used the Student t-test; for binary variables, we used the Fisher exact test. A p value less than 0.05 was considered statistically significant. RESULTS: In the evaluation of AP radiographs, an indicator of acetabular retroversion-the crossover sign-showed no differences between the sexes, whereas the posterior wall sign (females 46% [45 of 98] hips versus males 75% [18 of 24] hips, OR 3.50 [95% confidence interval (CI) 1.20 to 11.71]; p = 0.01) and pelvic width index less than 56% (females 1% [1 of 98] versus males 17% [4 of 24], OR 18.71 [95% CI 1.74 to 958.90]; p = 0.005) occurred more frequently in males than in females. There were no differences in the iliac rotation parameters, but the ischium showed more external rotation in males (females 30° ± 2° versus males 24° ± 1°; p < 0.001). Regarding acetabular coverage, no differences between females and males were observed in the anterior acetabular sector angles. In contrast, males showed smaller values than females for the posterior acetabular sector angles (85° ± 9° versus 91° ± 7°; p = 0.002). In females, a correlation was observed between iliac rotation and acetabular sector angles (anterior acetabular sector angles: r = -0.35 [95% CI -0.05 to 0.16]; p < 0.001, posterior acetabular sector angles: r = 0.42 [95% CI 0.24 to 0.57]; p < 0.001). Similarly, ischial rotation showed a correlation with both acetabular sector angles (anterior acetabular sector angles: r = -0.34 [95% CI -0.51 to -0.15]; p < 0.001 and posterior acetabular sector angles: r = 0.45 [95% CI 0.27 to 0.59]; p < 0.001). Thus, in females, we observed that external iliac rotation and ischial internal rotation correlated with increased anterior acetabular coverage and reduced posterior coverage. In contrast, although acetabular coverage in males showed a correlation with iliac rotation (anterior acetabular sector angles: r = -0.55 [95% CI -0.78 to -0.18]; p = 0.006 and posterior acetabular sector angles: r = 0.74 [95% CI 0.48 to 0.88]; p < 0.001), no correlation was observed with ischial rotation. CONCLUSION: In males, acetabular retroversion occurs more commonly than in females and is attributed to their reduced posterior acetabular coverage. In females, an increase in the posterior acetabular coverage was correlated with the external rotation angle of the ischium, whereas in males, no correlation was found between ischial rotation and posterior acetabular coverage. In treating males with DDH via eccentric rotational acetabular osteotomy, it is essential to adjust bone fragments to prevent inadequate posterior acetabular coverage. Future studies might need to investigate the differences in acetabular coverage between males and females in various limb positions and consider the direction of bone fragment rotation. CLINICAL RELEVANCE: Our findings suggest that males with DDH exhibit acetabular retroversion more frequently than females, which is attributed to the reduced posterior acetabular coverage observed in males. The smaller posterior acetabular coverage in males might be related to differences in ischial morphology between sexes. During eccentric rotational acetabular osteotomy for males with DDH, adequately rotating acetabular bone fragments might be beneficial to compensate for deficient posterior acetabular coverage.

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 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: One hundred fifty-six 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 = .003). In terms of the T score examined by quantitative ultrasound, 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 = .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.

Extension of the Antero-Posterior Necrotic Regions Associated With Collapse Cessation in Osteonecrosis of the Femoral Head.

BACKGROUND: Collapse cessation is of utmost importance following a long period of collapse due to osteonecrosis of the femoral head (ONFH). This study investigated the relationship between collapse cessation and the extent of the necrotic regions of ONFH. METHODS: Overall, 74 patients who had symptomatic ONFH (collapse < 3 mm) at the first visit with a minimum follow-up of 3 years were included in this study. Patients were categorized based on collapse progression or cessation into the progression and stable groups. The extent of the antero-posterior (AP) and medio-lateral necrotic regions between the groups was assessed using sagittal and coronal sections of T1-magnetic resonance imaging. Additionally, the most effective cutoff value was determined from the receiving operating characteristic curve where collapse cessation could be obtained, while the survival rates were determined with collapse progression as the endpoints were evaluated. RESULTS: Overall, 45 and 29 patients were in the progression and stable groups, respectively. The AP and medio-lateral necrotic regions were significantly different (P < .01 and P < .01, respectively) between the progression and stable groups. A cutoff value of 62.1% of the AP necrotic regions was determined from the receiving operating characteristic curve analysis. The 5-year survival rates with collapse progression as the endpoints were 5.4 and 77.8% in the AP necrotic regions of ≥62.1 and <62.1%, respectively (P < .01). CONCLUSIONS: Cases with AP necrotic regions of ≤62.1% can be expected to have collapse cessation, which could be a useful index for ONFH treatment strategies. LEVEL OF EVIDENCE: Level IV.

Risk factors for intraoperative femoral fractures in cementless bipolar hip arthroplasty for femoral neck fracture in multicenter: The TRON group study.

BACKGROUND: Intraoperative femoral fractures are more common in cementless bipolar hip arthroplasty (BHA) for displaced femoral neck fractures than they are in cemented BHA and remain one of the major concerns. This study aimed to investigate the risk factors for intraoperative femoral fractures in cementless BHA. METHODS: The study included 1,392 patients who underwent cementless BHA for displaced femoral neck fractures from January 2015 to December 2019 in 14 hospitals of the Trauma Research Group. They were divided into two groups according to the presence or absence of intraoperative femoral fractures, and factors associated with intraoperative fractures were statistically examined. RESULTS: Forty (2.9 %) intraoperative and 28 (2.0 %) postoperative, totally 68 (4.9 %) femoral fractures occurred. The mean age of the patients, presence of opposite-side proximal femoral fracture, approach, and cementless stem design were significantly different between the two groups (P < 0.05). The logistic regression analysis model showed that a fully HA-coated stem (odds ratio, 4.12; 95 % confidence interval, 1.43-11.9) was an independent factor associated with intraoperative femoral fractures. CONCLUSION: This study investigated the risk factors associated with intraoperative fractures and showed that fully HA-coated stems were an independent factor associated with intraoperative femoral fractures. Surgeons should be cautious in the early stages of introducing fully HA-coated stems.

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.

Risk factors for nonunion in femoral neck fracture patients with internal fixation: A multicenter (TRON group) retrospective study.

INTRODUCTION: Femoral neck fractures (FNFs) are common in elderly individuals. When minimally displaced, they are typically treated with internal fixation. Nonunion is a complication of internal fixation of FNF, that sometimes necessitates reoperation. Radiographic parameters, including the Pauwels angle and posterior tilt angle, are risk factors for nonunion. However, these parameters are assessed solely in a two-dimensional context. We developed a novel radiographic parameter named the "Kindex." This multicenter investigation aimed to identify risk factors for nonunion following FNF fixation and evaluate the validity of this index. METHODS: This retrospective multicenter study collected data from 939 FNF patients who underwent internal fixation between 2016 and 2020 at 11 facilities (TRON group). The following exclusion criteria were applied: age <65, insufficient data, and Garden Stage III or IV fracture. Patient data, including age, sex, BMI, ASA classification, alcohol and smoking history, and comorbidities, were recorded. Radiographic measurements of the Pauwels angle and posterior tilt angle at the time of injury were used to calculate the Kindex. Correlations between the Pauwels angle, posterior tilt angle, Kindex, and nonunion were evaluated. A multivariate logistic regression analysis was performed to investigate independent risk factors for nonunion. A receiver operating characteristic (ROC) analysis was performed to determine the cutoff value of the Kindex, and the area under the curve (AUC) was calculated. RESULTS: The study included 594 patients (males, n = 151; females, n = 443; average age, 80.9 years). Nonunion was observed in 13 cases (2.2 %). While the Pauwels angle and posterior tilt angle did not show significant correlations, the Kindex exhibited strong correlations with both parameters. In the multivariate analysis, the Kindex and renal impairment were independent risk factors for nonunion (Kindex: OR 1.06, p = 0.015; renal impairment: OR 1.48, p = 0.021). In the ROC analysis, a Kindex of 50 was identified as the optimal cutoff value (AUC 0.72). CONCLUSION: The nonunion rate after internal fixation of FNF was 2.2 %. Renal impairment and the Kindex were identified as independent risk factors. The Kindex at the time of injury may serve as a novel radiographic parameter to consider when evaluating the need for internal fixation in FNF cases.

Elderly trochanteric fracture outcomes: Unveiling the risks of excessive postoperative sliding - A retrospective multicenter (TRON group) investigation.

BACKGROUND: Intramedullary nailing (IMN) for femoral trochanteric fractures (FTF) is the primary surgical intervention. Excessive lag screw sliding (ES) of the femoral neck screw sometimes occurs. This multicenter investigation sought to 1) determine the prevalence of ES, 2) evaluate the relationship between ES and postoperative complications, and 3) identify the factors of ES in elderly patients with FTF undergoing IMN. METHODS: From 2016 to 2020, 1448 patients with FTF were treated using a short IMN across 11 institutions (TRON group). Upon applying exclusion criteria, 519 patients (127 men, 392 women; mean age, 84.4 years) were included. The postoperative sliding distance was measured immediately after surgery and at final follow-up. A sliding distance of ≥8 mm categorized patients as having ES. We identify the factors contributing to ES using the logistic regression analysis, with a p < 0.05 as statistical significance. RESULTS: ES was observed in 116 patients (22.4 %). Patients with ES had a higher incidence of postoperative cut-out and peri-implant fracture. Logistic regression analysis showed that achieving optimal reduction in both AP and lateral views (odds ratio (OR) 0.48, p = 0.0012) and the use of a double screw system or twin screws with integrated locking mechanism significantly reduced the risk of ES (OR 0.27, 0.17; p = 0.0027, <0.001). CONCLUSIONS: The incidence rate of ES was 22.4 %. ES was associated with a higher risk of postoperative complications. The surgeons should aim for optimal reduction and use a double screw or twin screws with an integrated interlocking mechanism as the implant of choice.

Predictive factors for one-year mortality after surgery for periprosthetic femoral fracture: A retrospective multicenter (TRON group) study.

BACKGROUND: Periprosthetic femoral fracture (PFF) after total hip arthroplasty (THA) or bipolar hip arthroplasty (BHA) represents a challenging situation and the treatment is associated with high rates of complications and mortality. The aims of this multicenter retrospective study were to determine 1-year mortality and to identify predictors associated with mortality, including patient characteristics and surgical factors, in patients undergoing surgery for PFF after THA or BHA. METHODS: We collected 249 cases of PPF after THA or BHA that were treated in our 11 hospitals (named the TRON group) between January 2010 and December 2019. We excluded patients who were conservatively treated, cases in which the 1-year postoperative outcome was unknown, and Vancouver type A cases. Finally, we analyzed 161 patients. Univariate and multivariate Cox regression analyses were performed to identify factors affecting 1-year mortality. Patient-side factors such as age, BMI, fracture type, and preoperative mobility, and surgical factors such as surgical procedure, time to surgery, and operation time were analyzed respectively. RESULTS: Eighteen of 161 patients (11.2%) died one year after surgery. The multivariate Cox regression analysis identified older age, wheelchair status before injury, and operation time as independent predictors of 1-year mortality (older age: hazard ratio [HR] 1.07, 95% CI 1.01-1.15, P = 0.048; wheelchair status: HR 5.82, 95% CI 1.01-33.47, P = 0.049; operation time: [HR] 1.01, 95% CI 1.00-1.01, P = 0.00929). Meanwhile, fracture type according to the Vancouver classification, body mass index, presence of previous fragility fractures, type of fixation, blood loss during operation, and time to surgery were not independent predictors of 1-year mortality in this analysis. ConclusionThe 1-year mortality rate after surgery for PPFs patients was 11.2%. Factors associated with older and poor activity of daily living (ADL) performance (e.g., wheelchair status before injury), and longer operative time were associated with 1-year mortality after surgery for PPF. Surgeons should carefully plan treatment according to each patient's condition.

A large preoperative pelvic oblique angle affects perception of leg length discrepancy after total hip arthroplasty.

BACKGROUND: In some cases, patients feel a perceived leg length discrepancy (P-LLD) despite no radiographic leg length discrepancy (R-LLD) after total hip arthroplasty (THA). We aimed to investigate the rate of postoperative P-LLD and the factors that cause postoperative P-LLD. METHODS: A retrospective study was conducted on 100 patients with R-LLD ≤5 mm after THA. Patients were classified into two groups based on P-LLD post-THA: group P (with P-LLD) and group E (without P-LLD). Relevant data on the general characteristics and radiological findings between the two groups were compared. RESULTS: We observed that 25 & 75% of patients belonged to group P and group E, respectively, with no significant difference in patient background. Postoperative Japanese Orthopedic Association (JOA) classification of pain and activities of daily living scores were significantly lower in group P than in group E (37.2 ± 3.9 vs. 39.1 ± 2.2, respectively; P = 0.013, and 16.2 ± 4.2 vs. 18.2 ± 2.2, respectively; P = 0.011). The preoperative pelvic oblique angle (POA) was significantly larger in group P than in group E (3.3 ± 2.3° vs. -0.2 ± 2.1°; respectively; P < 0.01). The pelvis tilted toward the surgical side was significantly higher in group P than in group E(88% vs 57%; respectively; P = 0.013). The preoperative C7 coronal vertical axis (C7 CVA) was significantly larger in group P than in group E (6.7 ± 14.7 mm vs. -0.2 ± 10.3 mm; respectively; P = 0.028). Multivariate logistic analysis revealed that preoperative POA (OR, 3.71; 95% CI: 1.86-8.12; P < 0.01) and the pelvis tilted toward the surgical side (OR, 4.14; 95% CI: 2.07-9.71; P = 0.022) were independent risk factors for P-LLD after THA. CONCLUSION: Even though there was no postoperative R-LLD, 25% of patients had P-LLD. A large preoperative POA and the pelvis tilted toward the surgical side were independent risk factors for P-LLD after THA.

Effect of anaesthesia on cemented hemiarthroplasty -A multicentre retrospective study (TRON study).

INTRODUCTION: This study aimed to investigate the survival rate, postoperative complications, and walking ability in cemented hemiarthroplasty (HA) for displaced femoral neck fractures according to the anaesthesia method. METHODS: We conducted a retrospective study of a multicentre group (the TRON group). Three hundred fifty-eight patients who underwent cemented HA between 2015 and 2019 were selected; 289 patients of ≥75 years of age with no missing data were included. Patient background factors were matched and patients were assigned to spinal anaesthesia (SA) and general anaesthesia (GA) groups. The primary outcome was death at any time during the follow-up period. Secondary outcomes included postoperative complications and walking ability assessed using the Parker mobility score (PMS). Overall survival was evaluated using the Kaplan-Meier method, and differences were compared using the log-rank test. The incidence of each complication and PMS were compared between the two groups using Fisher's exact test. RESULTS: Overall survival during follow-up was significantly higher in the SA group in comparison to the GA group (p = 0.037). In the SA and GA groups, the survival rate at 3 months postoperatively was 98.4% and 95.5%, respectively. The incidence of postoperative pneumonia was significantly higher in the GA (p = 0.012), and PMS at 3 months postoperatively was significantly higher in the SA group (p = 0.016). CONCLUSION: The survival rate of elderly patients who underwent cemented HA was better in the SA group. General anaesthesia in cemented HA may be associated with lower life expectancy, increased incidence of pneumonia, and decreased walking ability.

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.

An appropriate method for predicting the femoral angle on whole-body X-ray images from full-spine X-ray images.

INTRODUCTION: The importance of lower-limb compensation in patients with spinal malalignment due to spinal pathologies has been emphasized. The latest whole-body X-ray images (WBX) have enabled evaluations of whole-body alignment from head to toe. However, WBX is still not commonly available. Thus, the present study aimed to examine an alternative measurement method of the femoral angle on usual full-spine X-ray images (FSX) that approximates the femoral angle on WBX. METHODS: A total of 50 patients (age, 52.8 ± 25.3 years; female, n = 26; male, n = 24) underwent WBX and FSX. The following parameters were measured on lateral view X-rays: WBX and FSX femoral angle (angle between the femoral axis and a perpendicular line); FSX femoral distance (distance from the center of femoral head to the distal femur on FSX); WBX intersection length (length between the center of the femoral head and the intersection point [the point at which the line connecting the center of the femoral head and the midpoint of the femoral condyle intersects the center line of the femur] on WBX). RESULTS: The WBX femoral angle, and FSX femoral angle were 0.16 ± 4.2°, and -0.53 ± 4.1°, respectively. The FSX femoral distance was 102.7 ± 41.1 mm. An ROC curve analysis revealed that the cut-off value of the FSX femoral distance associated with minimal difference in the WBX and FSX femoral angles (<3°) was 73 mm (sensitivity 83.3%, specificity 87.5%, AUC 0.80). The WBX intersection length was 105.3 ± 27.3 mm. CONCLUSION: To calculate the femoral angle on FSX that approximates the WBX femoral angle, the femoral distance on FSX ≥73 mm is preferable. We suggest using the FSX femoral distance within the range of 80 mm-130 mm as a simple numerical value that meets all criteria.

The anatomical relationship between the celiac artery and the median arch ligament in degenerative spinal surgery.

BACKGROUND: This study aimed to characterize the anatomical relationship between the spine, the celiac artery (CA), and the median arcuate ligament using preoperative contrast-enhanced computed tomography (CT) images of patients with spinal deformity who underwent surgical correction. METHODS: This retrospective study included 81 consecutive patients (34 males, 47 females; average age: 70.2 years). The spinal level at which the CA originated, the diameter, extent of stenosis, and calcification were determined using CT sagittal images. Patients were divided into two groups: CA stenosis group and non-stenosis group. Factors associated with stenosis were examined. RESULTS: CA stenosis was observed in 17 (21%) patients. CA stenosis group had significantly higher body mass index (24.9 ± 3.9 vs. 22.7 ± 3.7, p = 0.03). In the CA stenosis group, J-type CA (upward angling of the course by more than 90° immediately after descending) was more frequently observed (64.7% vs. 18.8%, p < 0.001). The CA stenosis group had lower pelvic tilt (18.6 ± 6.7 vs. 25.1 ± 9.9, p = 0.02) than non-stenosis group. CONCLUSIONS: High BMI, J-type, and shorter distance between CA and MAL were risk factors for CA stenosis in this study. Patients with high BMI undergoing fixation of multiple intervertebral corrective fusions at the thoracolumbar junction should undergo preoperative CT evaluation of the anatomy of CA to assess the poteitial risk of celiac artery compression syndrome.

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.