Objective To measure and analyze anatomic parameters of resected distal femurs and proximal tibias in Kaschin-Beck disease(KBD)and osteoarthritic(OA)knees which fit for total knee arthroplasty(TKA),so as to provide basis for designing suitable knee prosthesis for KBD patients.Methods A total of 154 knees(75 KBD and 79 OA)fitting for TKA underwent three-dimensional reconstruction;resection of distal femurs and proximal tibias was simulated during TKA.We measured the distal femoral mediolateral(fML),lateral anteroposterior(fLAP),medial anteroposterior(fMAP),medial condylar width(fMCW),lateral condylar width(fLCW)and fML/fLAP aspect ratio,proximal tibial mediolateral(tML),middle anteroposterior(tAP),medial anteroposterior(tMAP),lateral anteroposterior(tLAP)dimension,and tML/tAP aspect ratio to compare the morphometric differences between KBD and OA knees.Results The measured anatomic parameters of resected distal femurs and proximal tibias in both male and female patients of KBD group were smaller than those of OA knees(P＜0.01).We also found that KBD group had larger distal femur fML/fLAP and proximal tibia tML/tAP aspect ratios than those of OA knees(P＜0.01).This indicated that under a given AP dimension,KBD knees need an oval-shaped prosthesis with a wider ML length and more spherical-shaped prosthesis with relatively narrow ML dimensions in OA knees.Conclusion The anatomy of distal femurs and proximal tibias shows significant differences in size and shape between KBD and OA knees,which provides theoretical basis for designing proper knee prosthesis for KBD patients.

Objective To construct a trajectory model for the changes in body roundness index(BRI)of elderly people in China from 2011 to 2018 based on the data derived from Chinese Longitudinal Healthy Longevity Survey(CLHLS),and analyze the influencing factors of different BRI trajectories.Methods Based on the longitudinal cohort data from the CLHLS platform,group-based trajectory model(GBTM)analysis was used to construct longitudinal change trajectories of 3 waves of BRI(2011,2014,and 2018)that meet our research criteria.Unordered multinomial logistic regression analysis was employed to identify the influencing factors of different BRI trajectories.Results A total of 2 512 valid samples were included in the analysis.The BRI trajectory of Chinese elderly people fitted by GBTM was optimally grouped into low-,medium-,and high-level growth trajectory models.There were statistically significant differences among different BRI trajectory groups in gender,length of education,resident place,living with spouse,retirement pension,sleep quality,smoking history,drinking history,continuous exercise,frequency of fruit consumption,frequency of salt-preserved vegetables consumption,and"fruit+protein"dietary patterns(P<0.05).Disordered multiclass logistic regression analysis found that,using the low-level growth trajectory model as a reference,males and those with a history of smoking were less likely to exhibit moderate to high growth levels of BRI trajectories;Elderly people with retirement pensions were more likely to exhibit a moderate to high growth level of BRI trajectory;People with a history of alcohol consumption were more likely to exhibit a moderate steady growth level of BRI trajectory;People with longer than 10 years of education were less likely to exhibit a high level of growth in the BRI trajectory,while urban residents and those who frequently consumed fruits and salted vegetables were more likely to exhibit a high level of growth in the BRI trajectory.Conclusion The trajectory of BRI changes among elderly people in China from 2011 to 2018 can be divided into 3 groups,which are influenced by multiple factors such as gender,resident place,and length of education.It is necessary to pay attention to and make measures in advance to improve the quality of life in the elderly.Countermeasures It is advisable to incorporate BRI as a core indicator in elderly health monitoring systems,establish a dynamic management mechanism for high-risk populations,and implement precision-targeted lifestyle interventions and health guidance.

Objective To explore the gender differences and the influence of varus and valgus deformities on distal femur rotational alignment in patients with knee osteoarthritis so as to provide reference for the distal femur rotational osteotomy in total knee arthroplasty(TKA).Methods CT data of 125 knees with osteoarthritis suitable for TKA(including 56 males and 69 females;78 varus knees and 47 valgus knees)were collected and received three-dimensional imaging reconstruction with Mimics software.We measured the posterior condylar angle(PCA),the angle between the anteroposterior axis and the surgical epicondylar axis(ASA),and the angle between the anteroposterior axis and the posterior condylar axis(APA).We also compared gender differences and the influences of varus-valgus deformities on distal femur rotational alignments.Results The PCA and ASA values of distal femur rotational alignments were(3.5±1.1)° vs.(2.8±1.2)°(P=0.001)and(90.6±3.4)° vs.(91.9±3.5)°(P=0.028)for males and females,with statistically differences between the genders.There was no statistically difference in APA between males and females(P=0.482).The PCA values of distal femur rotational alignment in varus and valgus knees were(3.6±1.1)° and(2.9±1.2)°,with a statistically difference between the two groups(P=0.001).There were no statistically differences in ASA or APA between varus and valgus knees(P＞0.05).Conclusion Gender and varus-valgus deformities of knee joint affect the distal femur rotational alignment.Distal femur rotational osteotomy angle should be determined according to the patient's CT imaging before TKA to reduce the errors caused by individual differences and improve the accuracy of the distal femur rotational alignment during TKA.

Objective:To investigate the clinical characteristics of limb overgrowth following proximal femoral osteotomy (PFO) for unilateral developmental dysplasia of the hip (DDH) in children.Methods:A retrospective analysis was conducted on 36 children with unilateral DDH who underwent PFO at Xi'an Honghui Hospital from June 2017 to June 2021. The cohort included 4 males and 32 females, with a mean age of 4.23±3.15 years (range: 2-12 years), comprising 28 left-sided and 8 right-sided cases. According to the International Hip Dysplasia Institute (IHDI) classification, there were 2 type I, 9 type II, 16 type III, and 9 type IV cases. Radiographic parameters [femoral length, femoral neck anteversion angle, neck-shaft angle, acetabular index (AI), center-edge angle (CEA), center-head distance discrepancy (CHDD)] and PFO parameters (varus angle, shortening length, derotation angle) were measured on X-ray and 3D CT reconstructions. Comparisons were made between the overgrowth ≥1 cm group ( n=14) and <1 cm group ( n=22) to analyze risk factors and patterns. Results:The overgrowth ≥1 cm group had significantly younger patients (2.49±1.03 years vs. 5.13±3.47 years, t=-2.757, P<0.001). Overgrowth magnitude varied significantly across age subgroups: 11.08±6.17 mm in the 2-4 years group, 5.08±0.19 mm in the >4-<6 years group, and 2.44±4.50 mm in the ≥6 years group ( F=5.436, P=0.031). The highest incidence of overgrowth occurred in the 2-4 years subgroup (56%, 20/36). Limb overgrowth initiated at 3 months postoperatively, exhibited a linear correlation with follow-up duration during 6-18 months [ r=0.78, 95% CI(0.62, 0.88), P<0.001)], and plateaued after 18 months [ r=-0.15, 95% CI(-0.75, 0.57), P=0.710]. Postoperative CEA and CHDD showed significant improvements ( P<0.05), while AI remained unchanged ( P>0.05). Conclusions:Children aged 2-4 years exhibit higher incidence and severity of post-PFO limb overgrowth. The rapid progression phase occurs within 6-18 months postoperatively, stabilizing thereafter. CEA and CHDD serve as critical indicators for evaluating intervention efficacy in DDH-related overgrowth.

Objective:To investigate the clinical characteristics of limb overgrowth following proximal femoral osteotomy (PFO) for unilateral developmental dysplasia of the hip (DDH) in children.Methods:A retrospective analysis was conducted on 36 children with unilateral DDH who underwent PFO at Xi'an Honghui Hospital from June 2017 to June 2021. The cohort included 4 males and 32 females, with a mean age of 4.23±3.15 years (range: 2-12 years), comprising 28 left-sided and 8 right-sided cases. According to the International Hip Dysplasia Institute (IHDI) classification, there were 2 type I, 9 type II, 16 type III, and 9 type IV cases. Radiographic parameters [femoral length, femoral neck anteversion angle, neck-shaft angle, acetabular index (AI), center-edge angle (CEA), center-head distance discrepancy (CHDD)] and PFO parameters (varus angle, shortening length, derotation angle) were measured on X-ray and 3D CT reconstructions. Comparisons were made between the overgrowth ≥1 cm group ( n=14) and <1 cm group ( n=22) to analyze risk factors and patterns. Results:The overgrowth ≥1 cm group had significantly younger patients (2.49±1.03 years vs. 5.13±3.47 years, t=-2.757, P<0.001). Overgrowth magnitude varied significantly across age subgroups: 11.08±6.17 mm in the 2-4 years group, 5.08±0.19 mm in the >4-<6 years group, and 2.44±4.50 mm in the ≥6 years group ( F=5.436, P=0.031). The highest incidence of overgrowth occurred in the 2-4 years subgroup (56%, 20/36). Limb overgrowth initiated at 3 months postoperatively, exhibited a linear correlation with follow-up duration during 6-18 months [ r=0.78, 95% CI(0.62, 0.88), P<0.001)], and plateaued after 18 months [ r=-0.15, 95% CI(-0.75, 0.57), P=0.710]. Postoperative CEA and CHDD showed significant improvements ( P<0.05), while AI remained unchanged ( P>0.05). Conclusions:Children aged 2-4 years exhibit higher incidence and severity of post-PFO limb overgrowth. The rapid progression phase occurs within 6-18 months postoperatively, stabilizing thereafter. CEA and CHDD serve as critical indicators for evaluating intervention efficacy in DDH-related overgrowth.

Objective To measure and analyze anatomic parameters of resected distal femurs and proximal tibias in Kaschin-Beck disease(KBD)and osteoarthritic(OA)knees which fit for total knee arthroplasty(TKA),so as to provide basis for designing suitable knee prosthesis for KBD patients.Methods A total of 154 knees(75 KBD and 79 OA)fitting for TKA underwent three-dimensional reconstruction;resection of distal femurs and proximal tibias was simulated during TKA.We measured the distal femoral mediolateral(fML),lateral anteroposterior(fLAP),medial anteroposterior(fMAP),medial condylar width(fMCW),lateral condylar width(fLCW)and fML/fLAP aspect ratio,proximal tibial mediolateral(tML),middle anteroposterior(tAP),medial anteroposterior(tMAP),lateral anteroposterior(tLAP)dimension,and tML/tAP aspect ratio to compare the morphometric differences between KBD and OA knees.Results The measured anatomic parameters of resected distal femurs and proximal tibias in both male and female patients of KBD group were smaller than those of OA knees(P＜0.01).We also found that KBD group had larger distal femur fML/fLAP and proximal tibia tML/tAP aspect ratios than those of OA knees(P＜0.01).This indicated that under a given AP dimension,KBD knees need an oval-shaped prosthesis with a wider ML length and more spherical-shaped prosthesis with relatively narrow ML dimensions in OA knees.Conclusion The anatomy of distal femurs and proximal tibias shows significant differences in size and shape between KBD and OA knees,which provides theoretical basis for designing proper knee prosthesis for KBD patients.

Objective To explore the gender differences and the influence of varus and valgus deformities on distal femur rotational alignment in patients with knee osteoarthritis so as to provide reference for the distal femur rotational osteotomy in total knee arthroplasty(TKA).Methods CT data of 125 knees with osteoarthritis suitable for TKA(including 56 males and 69 females;78 varus knees and 47 valgus knees)were collected and received three-dimensional imaging reconstruction with Mimics software.We measured the posterior condylar angle(PCA),the angle between the anteroposterior axis and the surgical epicondylar axis(ASA),and the angle between the anteroposterior axis and the posterior condylar axis(APA).We also compared gender differences and the influences of varus-valgus deformities on distal femur rotational alignments.Results The PCA and ASA values of distal femur rotational alignments were(3.5±1.1)° vs.(2.8±1.2)°(P=0.001)and(90.6±3.4)° vs.(91.9±3.5)°(P=0.028)for males and females,with statistically differences between the genders.There was no statistically difference in APA between males and females(P=0.482).The PCA values of distal femur rotational alignment in varus and valgus knees were(3.6±1.1)° and(2.9±1.2)°,with a statistically difference between the two groups(P=0.001).There were no statistically differences in ASA or APA between varus and valgus knees(P＞0.05).Conclusion Gender and varus-valgus deformities of knee joint affect the distal femur rotational alignment.Distal femur rotational osteotomy angle should be determined according to the patient's CT imaging before TKA to reduce the errors caused by individual differences and improve the accuracy of the distal femur rotational alignment during TKA.

Objective:To construct the risk prediction model of unplanned readmission for elderly patients in emergency department within 30 days based on different machine learning algorithms, so as to help clinical staff identify high-risk patients early and formulate preventive interventions.Methods:A total of 1 207 elderly patients admitted to the emergency department of the First Affiliated Hospital of Naval Medical University from May 2022 to December 2023 were retrospectively selected as the study objects and were divided into the training set ( n = 842) and the test set ( n = 365) in a ratio of approximately 7∶3. Least absolute shrinkage and selection operator (LASSO) regression analysis was used to screen the factors affecting the unplanned readmission of elderly patients within 30 days. Six prediction models, including extreme Gradient Boost (XGBoost), Light Gradient Boosting Machine (LightGBM), Adaptive Boosting (AdaBoost) Logistic regression, K-nearest neighbor (KNN) and Gauss Naive Bayes classification (GNB) were constructed respectively. The models were summarized, evaluated and validated, and the importance of key variables was analyzed using Shapley Additive Interpretation (SHAP). Results:Among 1 207 elderly patients, there were 842 in the training set, 430 males with a median age of 77 years, and 365 in the test set, 176 males with a median age of 78 years. Eight variable features were selected by LASSO regression. The GNB model performed the best among the 6 prediction models constructed based on XGBoost, LightGBM, AdaBoost, Logistic regression, KNN, GNB. The AUC of the test set was 0.818, and the sensitivity was 0.890, while the specificity was 0.660, and the train set and the verification set had strong fitting ability and high stability. The eight characteristics affecting the unplanned readmitted of elderly patients in the emergency department within 30 days were ranked in importance by age, chronic obstructive pulmonary disease, length of stay, Charson comorbidity index≥3, hypoproteinemia, abnormal vital signs≥2, stroke, anemia.Conclusions:The GNB model based on machine learning algorithms for unplanned readmission of elderly emergency patients within 30 days has good predictive performance, which helps medical staff to identify high-risk patients as early as possible before discharge, formulate targeted preventive measures, thereby reducing the short-term unplanned readmission rate of patients and improving their quality of life.

Objective:To prepare biomimetic tissue engineering scaffolds of gelatin/sodium alginate/laponite composite hydrogel loaded with BMSCs by 3D biological printing technique，and explore the osteogenic effect of 3D printing on hydrogel scaffolds containing bone marrow mesenchymal stem cells（BMSCs）.Methods:BMSCs were routinely extracted and identified by flow cytometry. Gelatin，sodium alginate and laponite were mixed and then BMSCs were added to prepare cell-containing composite hydrogel scaffolds using 3D bioprinting. Non-printed scaffolds containing cells were prepared by injection molding method. In vitro，the prepared scaffolds were divided into the printing group with cells and non-printing group with cells according to whether they were printed，with 12 samples per group. Another simple cell culture group was set as control. Then，the internal structure of the composite hydrogel was observed by scanning electron microscope，and the expansion rate and water content of the scaffolds were measured by freeze-drying method. At day 3 after culture，the growth status of BMSCs was observed by phalloidine staining. cell counting kit（CCK）-8 assay was used to detect cell activity in scaffolds at days 1，3，and 7 after culture and RT-PCR to detect the expression of osteogenesis related genes Osterix，osteocalcin（OCN）and collagen I at days 7 and 14 ofter culture. In vivo，four groups were set according to printing or not and whether containing cells or not：printing implant group with cells，non-printing implant group with cells，printing implant group without cells and non-printing implant group without cells，with 9 samples per group. Scaffolds in four groups were implanted to the posterior gluteal muscle pouches（random on left or right）of 36 8-week-old SD rats，respectively. The samples were taken X-ray images at 2，4 and 8 weeks after operation，respectively. The osteogenic differentiation of tissues at 8 weeks was observed by HE and Masson staining. Results:The flow cytometry showed that the cells were BMSCs. Internal pores of hydrogels were obvious，and cells stretched freely in the pores. Differences of the swelling rate and water content were not statistically significant between printing group with cells［（1，039.37±30.66）%，（91.21±0.26）%］and non-printing group with cells［（1，032.38±35.05）%，（91.16±0.28）%］（ P>0.05）. At day 3 after culture in vitro，the cells grew well in the hydrogel. After culturing for 1 day in vitro，there was no significant difference in absorbance between printing group with cells and non-printing group with cells（ P>0.05）. At day 3 after culture，there was no significant difference in absorbance between printing group with cells and non-printing group with cells，but both groups showed a higher level than simple cell culture group（ P<0.05）. At day 7 after culture，the absorbance in printing group with cells（2.72±0.17）was higher than that in non-printing group with cells（2.35±0.11），and both of which were higher than that in simple cell culture group（1.95±0.12）（ P<0.05）. At day 7 after culture in vitro，there was no statistically significant difference in the expression of osteogenic differentiation-related genes between printing group with cells and the non-printing group with cells（ P>0.05），but they were all higher than those in simple cell culture group（ P<0.05）. At day 14 after culture in vitro，the expression of osteogenesis-related genes Osterix（1.650±0.095），OCN（2.725±0.091），collagen I（2.024±0.091）in printing group with cells were higher than those in non-printing group with cells（1.369±0.114，2.174±0.198，1.617±0.082，respectively）and those in simple cell culture group（1.031±0.094，1.116±0.092，0.736±0.140，respectively）（ P<0.05）. After implantation for 2 weeks in vivo，with no statistically significant difference in the gray values of X-ray films in each group（ P>0.05）. At weeks 4 and 8 after implantation，the gray values of X-ray films in printing implant group with cells and non-printing implant group with cells were higher than those in printing implant group without cells and non-printing implant group without cells（ P<0.01）. At 8 weeks after implantation，HE staining showed that the scaffolds were degraded in different degrees and immersed with cells，with collagen production seen in Masson staining as well. Conclusions:Composite hydrogel scaffolds can provide a good three-dimensional environment for BMSCs growth. 3D bioprinting can promote the proliferation and osteogenic differentiation of BMSCs in hydrogel scaffolds. In addition，BMSCs-loaded scaffolds can be degraded slowly in vivo with good ectopic osteogenic ability.

Objective To systematically evaluate the biomechanical recovery of drilled holes in the femur in SD rats.Methods Eighteen female SD rats were randomized into 3 even groups (n =6).Models of 2-mm drilled holes in bilateral femurs were established in groups A and B with 2 holes on each side while no drilling was performed in group C.Samples were harvested in group A at postoperative 4 weeks,in group B at postoperative 8 weeks while at both 4 and 8 weeks in group C.The samples were evaluated in terms of linear elasticity (compression test),viscoelasticity (relaxation and creep tests) and durability (fatigue failure test).Micro-CT scan was performed to measure the bone volume fraction (BV/TV) and bone mineral density (BMD) of new bone.Sirus red staining was performed to measure regeneration of type Ⅰ collagen of new bone.Results The elasticity modulus,maximum load,compression strength and conditional yield limit in groups A were significantly lower than those in group B which were also significantly lower than those in group C (P ＜ 0.05).At 7,200 s,the relaxation (14.56 ±0.69 MPa) and creep variation (11.37％ ± 0.70％) in group A were significantly higher than those in group B (11.06 0.63 MPa and 8.98％ ± 0.40％) which were also significantly higher than those in group C (6.99 ±0.56 MPa and 5.10％ ±0.23％) (P ＜ 0.05).At the constant amplitude loads from 20 N to 200 N,from 20 N to 300 N and from 20 N to 400 N,the recycling numbers in group A (6,044.3 ±879.7,4,093.3 ±628.5 and 1,919.3 ±847.5) were significantly lower than those in group B (10,192.3 ± 1,109.1,6,750.6 ± 818.0 and 3,376.6 ± 671.3) which were also significantly lower than those in group C (28,068.3 ±2,702.6,11,788.3 ± 1,141.6 and 5,296.3 ± 735.0) (P ＜ 0.05).By micro-CT scan,the BVT and BMD in group A were significantly lower than those in group B which were also significantly lower than those in group C (P ＜ 0.05).The sirus red staining showed the type Ⅰ collagen in the bone defect area was completely regenerated in group B.Conclusion Systematic biomechanical measurements may actually detect the characteristics of biomechanical recovery of bone holes in SD rats,enriching the basic research on the bone damage repairing progress.