CD34+ synovial fibroblasts exhibit high osteogenic potential in synovial chondromatosis.

Synovial chondromatosis (SC) is a disorder of the synovium characterized by the formation of osteochondral nodules within the synovium. This study aimed to identify the abnormally differentiated progenitor cells and possible pathogenic signaling pathways. Loose bodies and synovium were obtained from patients with SC during knee arthroplasty. Single-cell RNA sequencing was used to identify cell subsets and their gene signatures in SC synovium. Cells derived from osteoarthritis (OA) synovium were used as controls. Multi-differentiation and colony-forming assays were used to identify progenitor cells. The roles of transcription factors and signaling pathways were investigated through computational analysis and experimental verification. We identified an increased proportion of CD34+ sublining fibroblasts in SC synovium. CD34+CD31- cells and CD34-CD31- cells were sorted from SC synovium. Compared with CD34- cells, CD34+ cells had larger alkaline phosphatase (ALP)-stained area and calcified area after osteogenic induction. In addition, CD34+ cells exhibited a stronger tube formation ability than CD34- cells. Our bioinformatic analysis suggested the expression of TWIST1, a negative regulator of osteogenesis, in CD34- sublining fibroblasts and was regulated by the TGF-ß signaling pathway. The experiment showed that CD34+ cells acquired the TWIST1 expression during culture and the combination of TGF-ß1 and harmine, an inhibitor of Twist1, could further stimulate the osteogenesis of CD34+ cells. Overall, CD34+ synovial fibroblasts in SC synovium have multiple differentiation potentials, especially osteogenic differentiation potential, and might be responsible for the pathogenesis of SC.

Utilization of the Caprini risk assessment model(RAM) to predict venous thromboembolism after primary hip and knee arthroplasty: an analysis of the Healthcare Cost and Utilization Project(HCUP).

PURPOSE: This study aims to investigate the potential role of Caprini risk assessment model (RAM) in predicting the risk of venous thromboembolism (VTE) in patients undergoing total hip or knee arthroplasty (THA/TKA). No national study has investigated the role of Caprini RAM after primary THA/TKA. METHODS: Data from The National Sample of Healthcare Cost and Utilization Project (HCUP) in 2019 were utilized for this study. The dataset consisted of 229,134 patients who underwent primary THA/TKA. Deep vein thrombosis (DVT) and pulmonary embolism (PE) were considered as VTE. The incidence of thrombosis was calculated based on different Caprini scores, and the risk of the Caprini indicator for VTE events was evaluated using a forest plot. RESULTS: The prevalence of VTE after primary THA/TKA in the U.S. population in 2019 was found to be 4.7 cases per 1000 patients. Age, body mass index (BMI), and Caprini score showed a positive association with the risk of VTE (P < 0.05). The receiver operating characteristic (ROC) curve analysis indicated that a Caprini score of 9.5 had a sensitivity of 47.2% and a specificity of 82.7%, with an area under the curve (AUC) of 0.693 (95% CI, 0.677-0.710). The highest Youden index was 0.299. Multivariate logistic regression analysis revealed that malignancy, varicose vein, positive blood test for thrombophilia, history of thrombosis, COPD, hip fracture, blood transfusion, and age were significant risk factors for VTE. Based on these findings, a new risk stratification system incorporating the Caprini score was proposed. CONCLUSIONS: Although the Caprini score does not seem to be a good predictive model for VTE after primary THA/TKA, new risk stratification for the Caprini score is proposed to increase its usefulness.

Comparative Efficacy and Safety of Measures for the Treatment of Adults with Isolated Calf Muscular Vein Thrombosis: A Systematic Review and Network Meta-analysis.

BACKGROUND: Isolated calf muscular vein thrombosis (ICMVT) can result in pulmonary embolism, but the treatment of ICMVT remains controversial. Therefore, the purpose of the present study was to investigate the optimal treatment for the ICMVT by comparing the efficacy and safety of different treatments. METHODS: A network meta-analysis was conducted to search for studies published from database inception to April 30, 2022, that compared the outcomes of 2 or more treatments for ICMVT. The primary outcomes were efficacy (resolution rate) and safety (adverse reactions). Data were extracted following predefined hierarchy and the Cochrane Collaboration risk of bias tool was used to evaluate the methodological quality of the included studies. We estimated summary odds ratios with 95% credibility intervals using Bayesian network meta-analysis with random effects. RESULTS: A total of 16 studies were enrolled in the study. In terms of efficacy and safety, urokinase thrombolysis combined with low-molecular-weight heparin (LMWH) was most effective but had the lowest safety, while physical therapy was safest but had the lowest efficacy. More important, direct oral factor Xa inhibitors were most likely to be second most effective and safe compared with other treatments. For the duration of treatment, anticoagulant therapy for at least 3 months could effectively increase the resolution rate of ICMVT. CONCLUSIONS: Considering both efficacy and safety, taking direct oral factor Xa inhibitors for at least 3 months was the optimal treatment compared to LMWH, urokinase thrombolysis combined LMWH, physical therapy and warfarin for patients with ICMVT.

Follow-up study of isolated calf muscular vein thrombosis for anticoagulant therapy after primary hip and knee arthroplasty.

BACKGROUND: Although isolated calf muscular vein thrombosis (ICMVT) is commonly seen after hip and knee arthroplasty, no treatment guidelines for ICMVT after joint replacement are available. The purpose of this study was to evaluate the outcomes of patients with ICMVT for anticoagulant therapy at different time points after primary hip and knee arthroplasty. METHODS: Patients with ICMVT after primary hip and knee arthroplasty were included in the study. Diagnosis was established with Doppler ultrasound. Patients were followed up clinically and with Doppler ultrasound at 1, 2, and 3 months. The outcomes were efficacy (complete resolution) and acceptability (hemorrhagic events). Anticoagulant therapy at curative dosage was prescribed for 1 month and was extended for 2 additional months in case of incomplete resolution at 1 month or if propagation was present. The chi-square test was used to compare the outcomes at different time points. RESULTS: 302 patients were taken hip and knee arthroplasty from January 2021 to May 2022, in which 51 patients presented with 51 ICMVTs postoperatively. The incidence of ICMVT was about 16.89%. Resolution of ICMVT was considered complete at 1, 2, and 3 months at 36.73%, 61.22%, and 91.84%, respectively, with significant differences among the time points (P < 0.05). All patients with ICMVT receiving anticoagulant therapy remained free of propagations and hemorrhagic events within 3 months. CONCLUSION: Our findings provide new insights into the anticoagulant therapy for ICMVT after primary hip and knee arthroplasty, taking oral Rivaroxaban for 3 months is effective and safe, which contributes to provide the reference for clinical practice.

A prediction nomogram for deep venous thrombosis risk in patients undergoing primary total hip and knee arthroplasty: a retrospective study.

INTRODUCTION: Deep venous thrombosis (DVT) prediction after total hip and knee arthroplasty remains challenging. Early diagnosis and treatment of DVT are crucial. This research aimed to develop a nomogram for early DVT prediction. METHODS: A total of 317 patients undergoing primary total hip and knee arthroplasty in Sun Yat-sen Memorial Hospital were enrolled between May 2020 and September 2022. Data from May 2020 to February 2022 were used as the development datasets to build the nomogram model (n = 238). Using multivariate logistic regression, independent variables and a nomogram for predicting the occurrence of DVT were identified. Datasets used to validate the model for internal validation ranged from March 2022 to September 2022 (n = 79). The nomogram's capacity for prediction was also compared with the Caprini score. RESULTS: For both the development and validation datasets, DVT was found in a total of 38 (15.97%) and 9 patients (11.39%) on post-operative day 7 (pod7), respectively. 59.6% patients were symptomatic DVT (leg swelling). The multivariate analysis revealed that surgical site (Knee vs. Hip), leg swelling and thrombin-antithrombin complex (TAT) were associated with DVT. The previously indicated variables were used to build the nomogram, and for the development and validation datasets, respectively. In development and validation datasets, the area under the receiver operating characteristic curve was 0.836 and 0.957, respectively. In both datasets, the predictive value of the Nomogram is greater than the Caprini score. CONCLUSIONS: A proposed nomogram incorporating surgical site (Knee vs. Hip), leg swelling, and thrombin antithrombin complex (TAT) may facilitate the identification of patients who are more prone to develop DVT on pod7.

Post-operative complications of total knee arthroplasty in patients with hypertension.

BACKGROUND: Hypertension is one of the most common comorbidities among patients undergoing surgery. However, few studies have focused on patients undergoing knee arthroplasty, and most of them had small sample sizes. This study aimed to analyze post-operative complications associated with hypertension in patients who underwent knee replacement surgery. METHODS: Data from the 2019 National Inpatient Sample (NIS) database were used. Patients who underwent primary total knee arthroplasty (pTKA) and those who underwent aseptic revision total knee arthroplasty (rTKA) were analyzed separately. Propensity score matching was performed to reduce the effects of demographic factors and comorbidities other than hypertension on post-operative complications. A multinomial logistic regression that included all significantly different demographics and comorbidities was performed to verify the results and evaluate the odds ratios. RESULTS: A total of 107,981 patients who underwent pTKA and 6571 who underwent rTKA owing to mechanical complications were identified in the 2019 NIS database. Compared with the non-hypertension group, patients with hypertension had a higher risk of developing acute renal failure and electrolyte disorders after TKA. Further analysis revealed that hyponatraemia and hypokalaemia were associated with hypertension. CONCLUSIONS: Hypertension was associated with the incidence of acute renal failure after TKA. It is important to identify patients with risk factors for acute renal failure (in addition to hypertension) and take careful measures to prevent acute renal failure in them.

Single-cell RNA sequencing reveals the cell types heterogenicity of human discoid lateral meniscus cells.

Discoid lateral meniscus (DLM) is more prone to injury than a normally shaped meniscus. No study has compared the gene expression and cell heterogeneity between discoid and normal menisci. We aimed to identify specific cell clusters and their marker genes in discoid meniscus, thereby providing a theoretical basis for the treatment and etiology of DLM. ScRNA-seq was used in DLM and osteoarthritis lateral meniscus (OAM) cells to identify cell subsets and their gene signatures. Pseudo-time analysis and immunohistochemical staining were used to investigate the temporal and spatial distribution of DLM-specific clusters. ScRNA-seq identified nine clusters originating from DLM and OAM, composed of seven empirically defined populations and two novel populations specific to DLM, namely, the prehypertrophic chondrocyte 2 (PreHTC-2) and regulatory chondrocyte (RegC-2) populations. Single-cell trajectory showed that RegC-2 and PreHTC-2 were mainly distributed in a specific cell fate, with the PreHTC-2 marker gene HAPLN1 highly expressed at the end of this fate. Immunohistochemical staining showed that HAPLN1 + cells were mainly distributed in the white zone of DLM. Matrix metalloproteinase (MMP) variants were expressed in DLM and OAM, with MMP2 highly expressed in OAM-dominant cell clusters, while MMP3 was highly expressed in DLM-dominant cell clusters. We concluded that two novel cell clusters including PreHTC-2 were identified using single-cell sequencing, which were mainly distributed in the white areas of DLM. Differentiated MMP expression in the trajectory may be a possible mechanism of DLM formation.

Thrombin antithrombin complex concentration as an early predictor of deep vein thrombosis after total hip arthroplasty and total knee arthroplasty.

AIM: Early predictive markers of venous thromboembolism (VTE) after total hip arthroplasty (THA)/total knee arthroplasty (TKA) remain unclear. Our study identified early predictive markers for VTE after THA/TKA. METHODS: A single-institution retrospective review study was conducted between May 2020 and April 2022 (n = 256). All patients underwent Doppler ultrasounds exam in preoperation and seventh day after surgery. Deep vein thrombosis (DVT) was defined by Doppler ultrasound of the lower extremities, which revealed thrombosis. Thrombin-antithrombin complex (TAT), thrombomodulin (TM), and plasmin-antiplasmin complex (PIC) concentration were tested from each patient's preoperative and postoperative days 1, 4, 7, 14. These values were then accessed via receiver operating characteristic (ROC) curve analysis and further quantified the level of this risk by concentration. RESULTS: On postoperative day 1 (pod-1), all patients' TAT and PIC concentrations were significantly higher than those preoperatively (p < 0.05). The levels of TAT and PIC in patients in the DVT group on pod-1 were significantly higher than those in the non-DVT group (p < 0.05). At pod-1, the TAT concentration for DVT patients was 49.47 ng/mL compared to 20.70 ng/mL for non-DVT patients, PIC was 3.72µg/mL compared to 1.65µg/mL. ROC curve analysis demonstrated that a TAT concentration of 24.3 ng/mL had a sensitivity of 87.9% and a specificity of 69.1%. CONCLUSION: TAT levels on pod-1 may predict DVT early after THA/TKA, which makes it possible for early intervention to decrease the incidence of DVT.

Ovarian Hormones and Reward Processes in Palatable Food Intake and Binge Eating.

Ovarian hormones are associated with risk for binge eating in women. Recent animal and human studies suggest that food-related reward processing may be one set of neurobiological factors that contribute to these relationships, but additional studies are needed to confirm and extend findings.

Eating disorders treatment experiences and social support: Perspectives from service seekers in mainland China.

OBJECTIVE: This study explored treatment experiences and social support among individuals with eating disorders (EDs) in mainland China. METHOD: Subscribers of a Chinese online social media platform (WeChat) focused on EDs were invited to complete a screening questionnaire that included the Eating Disorder Diagnostic Scale for the DSM-5. Of the 116 questionnaire responses, 31 met inclusion criteria for follow-up interviews. Individuals who never sought treatment were not eligible for follow-up interviews, but provided brief explanations about why they did not seek treatment. All eligible participants (n = 31) completed a semi-structured interview about their experiences with ED treatment and social support. Qualitative data from the interviews and survey responses regarding not seeking treatment were subjected to inductive data-driven thematic analysis with deductive coding to illuminate treatment and social support experiences or reasons for not seeking treatment. RESULTS: Themes emerged from interviews revealed positive inpatient treatment experiences for anorexia nervosa, but negative outpatient treatment experiences, unaffordable care, and ineffective psychopharmacological treatments. Parents, friends, and partners were sources of social support, but participants largely felt misunderstood or blamed by these same entities. Shame, not recognizing ED as an illness, and financial constraints were listed as the primary reasons for not seeking treatment. DISCUSSION: The importance of hearing patients' perspectives, improving ED literacy in China, increasing knowledge of culturally specific manifestations of EDs, and developing culturally responsive services and dissemination of treatment resources are emphasized.

Bridge Centrality: A Network Approach to Understanding Comorbidity.

Recently, researchers in clinical psychology have endeavored to create network models of the relationships between symptoms, both within and across mental disorders. Symptoms that connect two mental disorders are called "bridge symptoms." Unfortunately, no formal quantitative methods for identifying these bridge symptoms exist. Accordingly, we developed four network statistics to identify bridge symptoms: bridge strength, bridge betweenness, bridge closeness, and bridge expected influence. These statistics are nonspecific to the type of network estimated, making them potentially useful in individual-level psychometric networks, group-level psychometric networks, and networks outside the field of psychopathology such as social networks. We first tested the fidelity of our statistics in predicting bridge nodes in a series of simulations. Averaged across all conditions, the statistics achieved a sensitivity of 92.7% and a specificity of 84.9%. By simulating datasets of varying sample sizes, we tested the robustness of our statistics, confirming their suitability for network psychometrics. Furthermore, we simulated the contagion of one mental disorder to another, showing that deactivating bridge nodes prevents the spread of comorbidity (i.e., one disorder activating another). Eliminating nodes based on bridge statistics was more effective than eliminating nodes high on traditional centrality statistics in preventing comorbidity. Finally, we applied our algorithms to 18 group-level empirical comorbidity networks from published studies and discussed the implications of this analysis.

Single-cell RNA-seq analysis identifies meniscus progenitors and reveals the progression of meniscus degeneration.

OBJECTIVES: The heterogeneity of meniscus cells and the mechanism of meniscus degeneration is not well understood. Here, single-cell RNA sequencing (scRNA-seq) was used to identify various meniscus cell subsets and investigate the mechanism of meniscus degeneration. METHODS: scRNA-seq was used to identify cell subsets and their gene signatures in healthy human and degenerated meniscus cells to determine their differentiation relationships and characterise the diversity within specific cell types. Colony-forming, multi-differentiation assays and a mice meniscus injury model were used to identify meniscus progenitor cells. We investigated the role of degenerated meniscus progenitor (DegP) cell clusters during meniscus degeneration using computational analysis and experimental verification. RESULTS: We identified seven clusters in healthy human meniscus, including five empirically defined populations and two novel populations. Pseudotime analysis showed endothelial cells and fibrochondrocyte progenitors (FCP) existed at the pseudospace trajectory start. Melanoma cell adhesion molecule ((MCAM)/CD146) was highly expressed in two clusters. CD146+ meniscus cells differentiated into osteoblasts and adipocytes and formed colonies. We identified changes in the proportions of degenerated meniscus cell clusters and found a cluster specific to degenerative meniscus with progenitor cell characteristics. The reconstruction of four progenitor cell clusters indicated that FCP differentiation into DegP was an aberrant process. Interleukin 1ß stimulation in healthy human meniscus cells increased CD318+ cells, while TGFß1 attenuated the increase in CD318+ cells in degenerated meniscus cells. CONCLUSIONS: The identification of meniscus progenitor cells provided new insights into cell-based meniscus tissue engineering, demonstrating a novel mechanism of meniscus degeneration, which contributes to the development of a novel therapeutic strategy.

Etiologic and treatment conceptualizations of disordered eating symptoms among mainland Chinese therapists.

OBJECTIVE: Reports of disordered eating are increasing in mainland China; however, little is known regarding Chinese psychotherapists' conceptualizations of disordered eating symptomatology. This study explores Chinese psychotherapists' conceptualizations of binge eating (BE)/vomiting symptoms and treatment considerations. METHOD: In-depth, semi-structured interviews were conducted with mainland Chinese psychotherapists (N = 41) in Mandarin. Participants were given a hypothetical case and provided their conceptualization of the patient's BE/vomiting etiology and treatment recommendations. Etiological conceptualizations were coded using directed content analysis, and treatment recommendations were grouped by intervention strategy. RESULTS: Participants described psychosocial risk factors for BE/vomiting including intrapersonal characteristics and the childhood family environment, but rarely discussed genetic and neurobiological factors. Few participants reported that they would prioritize the BE/vomiting symptoms in treatment and their specific treatment recommendations varied widely. DISCUSSION: Most research on BE/vomiting behaviors in the literature is based on Western samples with little attention to mainland Chinese populations. Participants in this study provided conceptualizations of risk factors and treatment recommendations that could generally find evidence in the existing Western literature, even if some theories are no longer supported by updated Western research and the participants focused primarily on psychosocial risks as opposed to genetic/neurobiological factors. It will be important for future research to ascertain mainland Chinese therapists' understanding of these additional types of risk. These findings also suggest a disconnect between clinical findings on neurobiological risks and Chinese therapists' knowledge and/or perceived clinical utility of these risks. Implications for treatment and research dissemination to diverse global communities are discussed.

3D simulation of radiographic projections to test and reduce the effect of pelvic tilt on the accuracy of cross-table lateral radiography.

BACKGROUND: Cross-table lateral (CL) radiography is a convenient and feasible method to assess cup version angle (VA) after total hip arthroplasty; However, pelvic tilt (PT) may contribute to its measurement inaccuracy. How PT affects CL radiographic measurements have not been well studied. We sought (1) to determine the effect of the PT on cup version measurement on CL radiography and (2) to develop a method for reducing measurement errors caused by the PT. METHODS: We used 3D technique to construct standard model and capture CL radiography simulation. A linear regression model was created to analyze the relationship between PT and VA. CL radiography and computed tomography (CT) were performed for the enrolled patients after surgery. The consistency between CL and CT measurements were verified by intra-class correlation coefficient (ICC). RESULTS: There was a high correlation between the VA and PT. For each 1-degree increased in the PT, the VA decreased by 0.76° (R2 = 0.995, p < 0.001). Based on the data, we created a corrective formula to convert the radiographic measurements into values approximating the actual VA under a natural pelvic position. The VA measurements corrected by our equation was in high agreement with the CT-measured values with reference to the corresponding PT (ICC = 0.988, p < 0.001), which was in sharp contrast to that without PT control (ICC = 0.454, p = 0.203). CONCLUSIONS: The PT may contribute to cup version measurement inaccuracies on CL radiography. Our mathematical algorithm can serve as a reliable method to improve the accuracy of CL radiography.

The fragility of perceived social rank following exercise in anorexia nervosa: an ecological momentary assessment study of shame and pride.

PURPOSE: Pride and shame are self-conscious emotions closely associated with perceived social rank. Goss and Gilbert (In: Gilbert and Miles (eds) Body shame: conceptualization, research & treatment. Brunner-Routledge, Hove, 2002) proposed that weight-control behaviours in anorexia nervosa (AN) provide a temporary sense of increased rank that dissipates afterwards, thereby perpetuating further symptoms. This pilot study tested their theory by examining whether shame increases and pride decreases as time passes post-exercise in individuals with AN. Pre-exercise patterns were also explored. METHODS: Over 2 weeks, 23 females with AN provided ecological momentary assessment data via six semi-random daily signals and after each exercise episode. The State Shame and Guilt Scale assessed pride and shame. Items modified from the Experience of Shame Scale and the Other as Shame Scale assessed general shame and body/eating shame. Multilevel models analyzed patterns of shame and pride prior to and following exercise episodes. RESULTS: In the hours after exercise, pride decreased, body/eating shame increased, and general shame increased on one measure. Pride was, therefore, higher and shame lower immediately after exercise as compared to later in the day. In the hours before exercise, pride increased, but shame levels did not change significantly. CONCLUSION: The anticipation and immediate aftermath of exercise may be associated with higher perceived social rank in people with AN, but their feelings about self may worsen as time passes after exercise. Fluctuations in shame and pride may contribute to the maintenance of exercise in people with AN. LEVEL OF EVIDENCE: IV, multiple time series analysis.

Application of Rapid Prototyping Pelvic Model for Patients with DDH to Facilitate Arthroplasty Planning: A Pilot Study.

Total hip arthroplasty (THA) is challenging in cases of osteoarthritis secondary to developmental dysplasia of the hip (DDH). Acetabular deficiency makes the positioning of the acetabular component difficult. Computer tomography based, patient-individual three dimensional (3-D) rapid prototype technology (RPT)-models were used to plan the placement of acetabular cup so that a surgeon was able to identify pelvic structures, assess the ideal extent of reaming and determine the size of cup after a reconstructive procedure. Intraclass correlation coefficients (ICCs) were used to analyze the agreement between the sizes of chosen components on the basis of preoperative planning and the actual sizes used in the operation. The use of the 3-D RPT-model facilitates the surgical procedures due to better planning and improved orientation.

DLL1/NOTCH1 signaling pathway maintain angiogenesis in meniscus development and degeneration.

OBJECTIVES: The decline in vascular capacity within the meniscus is a well-documented phenomenon during both development and degeneration. Maintaining vascular integrity has been proposed as a potential therapeutic strategy for osteoarthritis. Therefore, our study aims to investigate the characteristics of endothelial cells and blood vessels in embryonic and degenerated meniscus tissues. METHODS: Human embryonic and mature menisci were used for histological analyses. Single-cell RNA sequencing was used to identify cell clusters and their significant genes in embryo meniscus to uncover characteristic of endothelial cells. Computer analysis and various staining techniques were used to characterize vessels in development and osteoarthritis meniscus. RESULTS: Vessels structure first observed in E12w and increasing in E14w. Vessels were veins majorly and arteries growth in E35w. Endothelial cells located not only perivascular but also in the surface of meniscus. The expression of DLL1 was observed to be significantly altered in endothelial cells within the vascular network that failed to form. Meniscus tissues affected by osteoarthritis, characterized by diminished vascular capacity, displayed reduced levels of DLL1 expression. Experiment in vitro confirmed DLL1/NOTCH1 be vital to angiogenesis. CONCLUSION: Lack of DLL1/NOTCH1 signaling pathway was mechanism of vascular declination in development and degenerated meniscus.

An examination of individual, relational, and cultural risk for disordered eating in Asian American college students.

Objective: This study examined how individual (satisfaction of basic psychological needs), relational (perceived achievement- and dependency-oriented parental psychological control), and cultural (ethnic identity) factors may contribute to Asian American college students' (18 - 25 years of age) disordered eating. Participants: Asian American college students (N = 118) participated in the study. Methods: Participants completed a cross-sectional survey study. Moderated mediation models were used to analyze the data. Results: Analyses showed that perceived achievement-oriented, but not dependency-oriented, parental psychological control was more strongly associated with psychological needs satisfaction at higher, compared to lower, levels of ethnic identity. Conclusions: Findings highlighted the importance of both parenting and ethnic identity among Asian American college students' psychological needs and risk for disordered eating. The complex relations among achievement expectations, ethnic identity and wellbeing in Asian Americans are discussed. The results can inform intervention and prevention programs attending to the needs of this population.

Knee valgus deformity and lateral bone defects affect the function of superficial medial collateral ligament: A finite element analysis.

Purpose: The superficial medial collateral ligament (sMCL) is the primary restraint to valgus laxity of the knee, which is one of the significant indicators of implant selection in valgus knee. Our purpose is to explore the influence of knee valgus deformity and lateral bone defects in the function of sMCL. Methods: the right knee joint of a healthy male volunteer was subjected to CT and MRI scans. The scanned data were imported into Mimics, Geomagic, Solidworks and Ansys software to establish a three-dimensional finite element model of the human knee joint. Femorotibial angle (FTA)5°,10°,15°,20°,25°,30°,35° and lateral bone defect 0,0.5,1,1.5,2 cm are controlled in Solidworks. Tensile test in vitro of maximum load on sMCL was simulated in Ansys. Results: The peak stress of sMCL is raising with valgus deformity while there is no lateral defect. Increasing lateral bone defect can lessen the augmentation of the stress of sMCL caused by the valgus deformity. The peak stress of sMCL when it is in maximum load is 35.252 MPa. While valgus 35°, the peak stress of sMCL exceeds the value, with or without bone defect; the same is true for the valgus 30° with 0, 0.5, 1 cm bone defect and valgus 25° without defect. Conclusion: Our findings allow for preoperative evaluation of sMCL function in the valgus knee, which would play an instructive role to some extent for implant selection in total knee arthroplasty.

Reliability and validity of the functional combined anteversion measurement method using standing lateral radiography after total hip arthroplasty.

Background: The functional safe zone of combined anteversion (CA) shows a superior predictive value for dislocation after total hip arthroplasty (THA) compared to that of the Lewinnek safe zone. Thus, it is necessary to establish a feasible and accurate method for assessing CA for the evaluation of dislocation risk. We aimed to evaluate the reliability and validity of using standing lateral (SL) radiographs for determining CA. Methods: Sixty-seven patients who underwent SL radiography and computed tomography (CT) scans after THA were included. Radiographic CA values were obtained via the calculation of the sum of the acetabular cup and femoral stem anteversion (FSA) measurements as obtained from the SL radiographs. Acetabular cup anteversion (AA) was measured based on the tangential line to the face of the cup, whereas FSA was calculated using the developed formula based on the neck-shaft angle. The intra-observer and inter-observer reliabilities for each measurement were examined. Radiological CA values were compared with the CT scan measurements to evaluate their validity. Results: The intra-observer and inter-observer agreements of the SL radiography were excellent [intraclass correlation coefficient (ICC) ≥0.90]. The radiographic measurements correlated well with the CT scan measurements (r=0.869, P<0.001). The mean difference between the radiographic and CT scan measurements was -0.55°±4.68° and ranged from 0.3° to 2.2° in terms of the 95% confidence interval (CI). Conclusions: SL radiography is a reliable and valid imaging tool for the assessment of functional CA.