To sum up the methods which can be used to prevent dislocation after total hip replacement.Recent original articles about the reasons of dislocation and methods which were used to treat or prevent dislocation were extensively reviewed,and retrospective and comprehensive analysis was performed.Dislocation after THA can be reduced by careful assessment of patients,selecting suitable prosthesis,improving the position of prosthesis and avoidance risk movements.Dislocation after THA can be reduced by careful pre-,intra-,and postoperative assessment.

Objective To explore the value of the percentage of necrotic surface area in predicting collapse of osteonecrosis. Methods 15 hips of avascular necrosis of the femoral head(ANFH) in 9 patients underwent MRI scan. On the MRI films, the percentage of necrotic surface area were calculated. While on the specimens of the 15 hips, the percentage of necrotic surface area were also measured. In 16 hips of 8 patients of ANFH with serials MRI at mean 18.9 months intervals (range, 6-41 months), the percentage of necrotic surface area were calculated and compared. In 38 hips of 27 patients without collapse, the percentage of necrotic surface area and the index of necrosis were calculated on MRI films. Follow-up was terminated when crescentic sign illustrated on X-ray film or CT demonstrated articular facet collapse. Those hips without collapse were followed up more than 24 months. The value of the percentag of necrotic surface area and the index of necrosis in predicting collapse of osteonecrosis was observed. Results The percentage of necrotic surface area were 63.23%?10.16% on specimens and 63.60%?7.78% on MRI films respectively. There were no significant differences between them. The percentage of necrotic surface area on specimens were coincidence with those on MRI. In the 16 hips with serials MRI; the percentage of necrotic surface area were 52.37%?19.91% on the first MRI films, 51.70%?21.29% on the second. There were no significant differences between them. This result revealed that the percentage of necrotic surface area did not vary with the extension of course of disease. In the 38 cases of early necrosis, 28(73.7%) hips collapsed and 10(26.3%) hips did not. The relative risk of the percentage of necrotic surface area was 1.043, and the relative risk of the index of necrosis was 1.020. No significant difference was found in ARCO staging for patients with or without femoral head collapse. It demonstrated that whether ischemic necrotic femoral head collapse or not had no relation with its ARCO stage. Conclusion The percentage of necrotic surface area can be used as more accurate predictor for future collapse.

[Objective]To explore the causes and treatments of recurrent dislocation after total hip replacement.[Method]From July 1999 to January 2007,there were 47 cases of dislocation after total hip replacement.Thirteen cases were recurrent.CT and serial X-rays were taken to observe the position of prosthesis.The strength of their hip abductor was also tested.Stability test was used to value the stability of hip.Closed reduction,modular adjustments and revision were adopted according to patients,willingness,prosthesis and stability.[Result]All of the 13 patients had malposition.Eleven cases were tested with instability.Five cases were successfully treated by closed reduction.Despite dislocation reoccurred 1～2 times every year in 3 patients treated by closed reduction,patients felt satisfactory.In the 4 cases with modular revision procedure,2 cases changed the neck length,1 case used elevated liner and larger neck length,1 cases treated by using larger offset and adjusting abnormal liner.Another one treated by revision.[Conclusion]Malposition is the major causes of recurrent dislocation.The prosthesis test whowed instability.The treatments of recurrent dislocation after THA should use different ways according to the causes of dislocation,stability of prosthesis and the willingness of patients.

Objective:To analyze the causes of early dislocation after total hip replacement and explore its preventions and treatments. Methods:From July 1997 to October 2002, there were 12 cases of dislocation after total hip replacement. The strength of their hip abductor was tested and the X-ray films were measured. If closed reduction failed, capsular repairing was used. Results:There were 3 cases of malposition, 5 cases of abnormal soft-tissue tension, 3 cases of malposition and abnormal soft-tissue tension and 1 case of over motion. Close reduction was succeeded in 5 cases, 7 cases failed to close reduction, and were treated successfully by repairing the hip capsule and readjusted the prostheses when necessary. Conclusion:Abnormal soft-tissue tension has become the main causes of dislocation after total hip replacement. Those cases in which closed reduction has failed can be treated by repairing the hip capsule.

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.

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 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 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 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.

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.