Objective:To explore the early effects and safety of using a hybrid fixation strategy with 3D-printed porous tantalum metal augments to reconstruct substantial bone defects in complex primary total knee arthroplasty (TKA).Methods:A retrospective analysis was performed on the clinical data from August 2019 to September 2023, encompassing 20 patients (21 knees) with significant bone loss who underwent hybrid fixation with 3D-printed porous tantalum augments. The procedures were conducted at two medical centers: the First Affiliated Hospital, School of Medicine, Zhejiang University (11 cases) and Xiangya Hospital of Central South University (9 cases). The study cohort comprised 6 males (6 knees) and 14 females (15 knees), with a mean age of 61.05±11.23 years (range, 42-80 years). The distribution of cases was 7 on the left side and 14 on the right side. All cases were categorized as type 3 according to the Anderson Orthopaedic Research Institute (AORI) classification system. The cohort included 19 unilateral and 1 bilateral case, with 5 involving complex primary replacements (3 with Charcot arthropathy, 1 with syphilitic arthropathy, and 1 with severe valgus deformity) and 16 revision surgeries (13 for aseptic loosening and 3 for infection). Preoperative assessments included routine CT scans and digital three-dimensional reconstructions to identify large metaphyseal defects exceeding 50% of the metaphyseal area or those thicker than 10 mm. For such defects, 3D-printed standardized porous tantalum augments were implemented. In cases of extensive cavitary bone defects or severe metaphyseal defects where the medial and lateral defects collectively exceeded 80% of the metaphyseal region or where the residual bone stock was insufficient for screw fixation of standardized augments, 3D-printed personalized custom-made porous tantalum augments were employed for hybrid fixation and repair. Comparative analyses were conducted on pre- and postoperative imaging data (prosthesis positioning and complications), knee range of motion (ROM), visual analogue scale (VAS) for pain, and Knee Society score (KSS).Results:Of the cases, 17 were repaired using standardized 3D-printed porous tantalum augments, while 4 underwent repairs with customized augments for hybrid fixation. Follow-up averaged 26.5±15.0 months (range, 12-62 months). There was a significant increase in knee ROM, improving from 72.8°±31.9° preoperatively to 113.2°±6.8° at 12 months postoperatively ( P<0.05). VAS scores decreased from 6.6±1.4 preoperatively to 2.5±1.0 at 12 months postoperatively ( P<0.05). Similarly, KSS improved from 52.8±6.4 preoperatively to 80.7±7.9 at 12 months postoperatively ( P<0.05). There were no incidences of prosthesis displacement, poor bone integration, or postoperative infections. Conclusion:The hybrid fixation strategy employing 3D-printed porous tantalum augments has been found to be effective in addressing significant bone defects in TKA. The follow-up results indicate a satisfactory biological integration of the porous tantalum metal augments with the host bone, which has resulted in substantial improvements in pain relief and knee joint functionality.

Since the global COVID-19 pandemic, SARS-CoV-2 infection, which causes COVID-19, has been associated with a range of diseases whose atypical manifestations have been increasingly reported. The mild encephalitis or encephalopathy associated with reversible corpus callosum lesions or mild encephalitis/encephalopathy with reversible splenial lesion (MERS) is a rare clinical and radiographic syndrome. At present, the pathogenesis of MERS caused by COVID-19 is still unclear, and its pathogenesis may include hypoxic damage, inflammatory response, immune disorders, changes in osmotic pressure, excitatory amino acid toxicity, oxidative stress and functional abnormalities of renin-angiotensin system. This paper reports a case of severe COVID-19 complicated with MERS, and discusses the pathogenesis from a pathophysiological point of view.

Objective: To investigate the effect of glucocorticoid (GC) to cortisol-binding globulin (CBG) expression in rats and the correlation between the changes of CBG levels and the osteonecrosis of the femoral head (ONFH) in rats after GC treatment. Methods: A total of 72 healthy adult SD rats were randomly divided into low-dose group and high-dose group by computer random grouping.Thirty-six rats of low-dose group were injected dexamethasone at a dose of 1.5 mg·kg^-1·d^-1.Thirty-six rats of high-dose group were injected dexamethasone at a dose of 3.0 mg·kg^-1·d^-1.The blood samples were regularly collected, CBG levels in blood samples were detected by Western-blotting.Rats were killed in batches, femoral head was collected and observed under light microscope after HE staining.The bone lacuna of each group was compared and the ratio of empty lacuna was calculated.Finally, the correlation between the change of CBG level and ONFH was evaluated. Results: On the first day after administration, the CBG level of the two groups decreased, and reached the lowest level on the seventh day of administration, and then gradually increased.The reduction of CBG level in the high dose group was greater.With the increase of time after treatment, the number and rate of bone lacuna void in the two groups increased gradually.28 days after treatment, the number of empty bone lacunae and the rate of empty bone lacunae in the low dose group were (6.75±0.42) and (13.98±2.19)%, respectively, which were lower than those in the high dose group[(11.03±0.62) and (21.99±3.17)%, t=4.864, 3.926, all P<0.05]. Conclusion The risk of ONFH is increased with the increase of the dose of dexamethasone, and there was no significant difference between the sexes.The decrease of serum CBG level after medication is correlated with the occurrence of ONFH.

Objective To analyze the risk factors of periprosthetic acetabular fracture in total hip arthroplasty (THA) and to discuss the prevention and management.Methods A total of 1 023 patients (1 168 hips) undergoing THA were retrospectively analyzed between January 2012 and June 2015.There were 421 males (507 hips) and 602 females (661 hips),aged from 23 to 96 years with mean age of 64.2± 15.0 years.Primary total hip arthroplasty was conducted in 1 053 hips,while revision surgery was conducted in 115 hips.The reasons of periprosthetic acetabular fracture were summarized.Age,gender,BMI,primary disease,left or right sides,surgical approach,osteoporosis,prosthetic type,the coverage rate of acetabulum-bone,and the amount of surgical operation annually were compared between non-fracture and fracture.Risk factors associated with the fracture were analyzed using chi square test followed by a multivariate logistic regression.Furthermore,revision surgery was compared with primary THA using chi square test.Results The incidence of intraoperative periprosthetic acetabular fractures was 2.8％ (33/1 168).The incidence of fracture was higher in revision surgery than that in primary THA (6.1％ vs.2.5％).Multivariate logistic regression showed that primary disease (developmental dysplasia of the hip and rheumatoid arthritis),osteoporosis,uncemented acetabular cup,the high-er coverage rate of acetabulum-bone,and the less amount of surgical operation annually were prone to appear periprosthetic acetabular fracture in primary THA.Among the 33 patients with acetabular fractures,13 cases (39.4％,13/33) were found intraoperatively and 20 cases (60.6％,20/33) postoperatively.Acetabular wall fractures were in 26 (78.8％,26/33),column fractures in 2 (6.1％,2/33),transverse fractures in 2 (6.1％,2/33) and quadrilateral surface fractures with prosthetic central dislocation in 3 (9.1％,3/33).Seven cases of 26 stable fractures and 6 cases of 7 unstable fractures were found intraoperatively.Acetabular wall fractures were fixed by additional augmentation screws or accepted no special treatment,and column fractures were fixed with plate.One quadrilateral surface fracture was accepted revision surgery using Jumbo cup,2 quadrilateral surface fractures and 2 transverse fractures with reconstruction cage.The patients were followed up for 42.3±13.7 months (range 29-60 months).The Harris hip score was 83.3±6.6 (range 72-94) at last follow-up.No complication,such as hip dislocation,osteolysis,and prosthetic loosening was reported.Conclusion Most of periprosthetic acetabular fiactures are wall fractures which could not endanger the periprosthetic stability.The detection rate of acetabular stable fracture is lower than that of unstable fracture in operation.Primary disease (developmental dysplasia of the hip and rheumatoid arthritis),osteoporosis,uncemented acetabular cup,the higher coverage rate of aeetabulum-bone,the less amount of surgical operation annually are the intraoperative risk factors which closely related to acetabular fractures of primary THA.The risk of intraoperative periprosthetic acetabular fractures in revision THA is higher than that in primary THA.

Objective To evaluate the technique and clinical results of the modular fluted tapered stems for treating periprosthetic femoral fractures in revision hip arthroplasty.Methods From August 2007 to February 2014,fourteen patients (14hips) with periprosthetic femoral fractures underwent revision hip arthroplasty with modular fluted tapered stem.A retrospective analysis was performed involving all patients who were followed-up more than 2 years.The subjects consisted of 4 males and 10 females with mean age of 73.4±6.6 years (range,62-82 years) at the time of revision.All patients were unilateral with 8 left hips and 6 right hips.The status of primary arthroplasty was bipolar hemiarthroplasty in 3 patients and total hip arthroplasty in 11 patients.Nine cases were with cemented stems,5 cases with uncemented stems.The interval from primary hip arthroplasty to revision surgery ranged from 40 to 163 months,with an average of 120.9±31.9 months.Eight cases with Vancouver type B3 periprosthetic femoral fracture were found preoperatively,6 cases with aseptic loosening and bone deficiency occurred periprosthetic femoral fracture during the operation.Based on the Paprosky classification system for femoral bone deficiency:type ⅢA in 8 hips,type ⅢB in 5 hips,type Ⅳ in 1 hip.Both the femoral and the acetabular components were revised in 9 patients.All femoral fractures were treated with cable fixation,and the cortical allograft struts were used to augment femoral bone stock in 7 patients.The patients were followed up at 6 weeks,3 months,6 months,9 months,12 months and annually thereafter.Harris Hip Score System and radiographic examination was used to evaluate the clinical results,including fracture union,implant stability,bone stock,hip joint function and postoperative complications.Results The mean duration of follow-up was 62.1 ±22.2 months (range,30-96 months).The mean times of fracture union were 6.2±2.5 months (range,3-12 months).The Harris Hip Score improved from 29.6± 10.3 preoperatively to 86.3±4.2 postoperatively (t=-21.6,P=0.00).Thirteen cases (93％,13/14) had the stem subsidence of 4.9±2.5 mm (range,0-9 mm).Thirteen cases (93％,13/14) were presented with femoral bony restoration.Two cases showed incorporation of the allograft in 7 patients.One patient developed deep venous thrombosis of lower limbs,and one suffered from subcutaneous hematomas after surgery.There was no infection,aseptic loosening,dislocation or periprosthetic fracture complications at the followup.Conclusion The short-medium term results of the modular fluted tapered prosthesis applied in periprosthetic femoral fractures are encouraging in revision hip arthroplasty.The present technology can provide reliable primary stability and can tolerate minimal subsidence postoperatively.

Objective To evaluate the efficacy and safety of total knee arthroplasty (TKA) with 3D printing guild plate by comparing with conventional TKA. Methods From May 2014 to September 2014, 40 patients suffered primary unilateral TKA were received, in which there were 11 males and 29 females, aged from 57 to 82 years with an average age of 68.5±6.3 years. The subjects were divided into two groups randomly. One group was treated with TKA with 3D printing guild plate while the other group was treated with the conventional TKA. The blood loss, operation time, post?operative Hospital for Special Surgery (HSS) score, range of motion (ROM), lower limb mechanical alignment and incidence of complication were compared with insignificant differences. Results The operation time in the 3D printing TKA group (103.4±11.7 min) was lower than that in the conventional TKA group (124.5±21.6 min), which was statistically significant (t=3.838, P=0.000). The blood loss in the 3D printing TKA group (370.2±96.0 ml) was lower than that in the conventional TKA group (510.0±235.9 ml), which was statistically significant (t=2.454, P=0.019). The post?operative ROM of knee in the 3D printing TKA group was 104.3° ± 15.5° and that in the conventional TKA group was 103.5° ± 12.5° (t=0.169, P=0.867). HSS scores in the 3D printing TKA group and in the conventional TKA group were 88.5±5.7 and 89.4±4.8, which was statistically insignificant (t=-0.633,P=0.530). Mechanical alignment in the 3D printing TKA group was 2.9°±1.1° and that in the conventional TKA group was 3.0°±0.9°, which was not statistically significant (t=-0.317, P=0.753). No obvious complication occurred in two groups. Conclusion TKA with 3D printing guild plate has similar results to conventional TKA in HSS score, mechanical alignment and ROM of knee, but it shortens operation time and decreases the blood loss.

Objective To explore the regular progressive pattern of nontraumatic osteonecrosis of the femoral head (ONFH) in order to establish the reliable and convenient new classification of ONFH.Methods The coronal section of the femoral head was divided into three pillars (medial,central and lateral).The mid-coronal section of the femoral head on MRI was selected.The China-Japan Friendship Hospital (CJFH)classification of ONFH was established according to the site of necrotic focus in three pillars.A total of 153hips with ONFH were classified according to CJFH classification and Japanese Investigation Committee (JIC)classification,respectively.The collapse rate was observed and compared between both classifications of ONFH.Results The CJFH classification for ONFH consists of 3 types:type A,the medial pillar was involved; type B,the medial and central pillars were involved; type C,the lateral pillar was involved.According to site of necrosis focus in the lateral pillar,the type C was divided into 3 types:C1,there pillars were involved but there still was some normal tissue in lateral pillar;,C2,partial central pillar and all lateral pillar were involved; C3,the whole femoral head was involved.The natural history of the ONFH showed the collapse rate of type C2 and C3 in CJFH classification (95.3％) was higher than that (72.3％) of type C2 in JIC classification.Conclusion The CJFH classification of ONFH based on three pillars is more sensitive than JIC classification in predicting collapse of the femoral head.Moreover,the CJFH classification is convenient to use.

Ras/Raf/MEK/ERK singal transduction plays an important role in cell proliferation, differentiation, apoptosis, metastasis and metabolism. This investigation focused on this signal pathway and chose farnesyl transferase (FTase) as the main target and Raf-1 kinase as the second target. A lot of compounds were selected to construct the pharmacophore models of farnesyl transferase inhibitors (FTIs) and Raf-1 kinase inhibitors by using computer-aided drug design (CADD). The pharmacophore of FTIs is constituted by a hydrogen bonding acceptor, an aromatic ring, a positive ionizable and two hydrophobic regions; the pharmacophore of Raf-1 kinase is constituted by a hydrogen donor, a hydrogen acceptor, a hydrophobic regions and an aromatic ring. There are some similarities between the two pharmacophores. After analysis of the constructions of these two pharmacophores, some new aminomethylbenzoic acid derivatives with good forecasting activity against both of FTase and Raf-1 kinase were designed with these new pharmacophore models.

Objective To study the capability of high field MRI in demonstrating the post-mortem fetal brains at different gestational age(GA).Methods One hundred and eight post-mortem fetal brains of 14-40 weeks GA were evaluated by 3.0 T MRI. Eleven brains of 14 to 27 weeks GA with good 3.0 T MRI images were chosen and scanned by 7.0 T MRI. The developing sulci, layered structures of fetal cerebral cortex and basal nuclei were evaluated on MRI of different Tesla(3.0 T and 7.0 T)and their results analyzed. Results On T_1 WI of 3.0 T MRI, the layered structures of fetal cerebral cortex were present at 14 weeks GA, the sulci were more accurately identified after 16 weeks GA. The basal nuclei were clearly distinguishable after 20 weeks GA. and these structures were better visualized as the GA increased. On T_2WI of 7.0 T MRI, the sulei, layered structures of fetal cerebral cortex and basal nuclei were shown more clearly at the same GA when compared to 3.0 T, especially the sulci at the early developmental stages. Conclusions T_1 WI of 3.0 T MRI could show the developing structures of post-mortem fetal brain well, but the T_2 WI of 7.0 T MRI were comparatively better.

Based on ninety three acetylcholinesterase inhibitors (AChEIs) which have the same mechanism of action but are different in structural characteristics, the pharmacophore model for acetylcholinesterase inhibitor was constructed by the CATALYST system. The optimal pharmacophore model with three hydrophobic units, a ring aromatic unit and a hydrogen-bond acceptor unit were confirmed (Weight=3.29, RMS=0.53, total cost-null cost=62.75, Correl=0.93, Config=19.05). This pharmacophore model will act on the double active site of acetylcholinesterase and is able to predict the activity of known acetylcholinesterase inhibitors that are used for clinical treatment of Alzheimer's disease (AD), and can be further used to identify structurally diverse compounds that have higher activity treating with Alzheimer's disease (AD) by virtual screening.