BACKGROUND:The studies about biomechanics of total knee arthroplasty were more, but the research on finite element analysis of the effect of total knee arthroplasty on proximal tibial reconstruction was not much.
OBJECTIVE:To study the effect of total knee arthroplasty on proximal tibial reconstruction using finite element analysis.
METHODS:We designed knee models of two materials:one was functional y graded material models of col agen and titanium composite materials;another was titanium al oy material model. We created two prosthesis material tibia-knee prosthesis model, and analyzed bone density distribution of proximal tibia, the maximum stress value of the medial tibia and the lateral tibia, and the maximum stress value of medial tibia and prosthesis junction, as wel as lateral tibia and prosthesis junction after knee arthroplasty.
RESULTS AND CONCLUSION:(1) Bone density of proximal tibia after total knee arthroplasty:The bone density of the knee prosthesis handle with medial and lateral tibia at the junction of tibial plateau was decreased than that of the initial state. Stress shielding effect was lower in col agen and titanium composite materials of functional y graded material models than that of titanium al oy material model. The bone density of shank end of the tibial prosthesis was obviously increased compared with the medial and lateral tibia, showing stress concentration. (2) The maximum stress value of the medial and the lateral tibia:The maximum stress value of the medial and the lateral tibia in col agen and titanium composite models was lower than that of titanium al oy material model. The maximum stress values of the lateral tibia of col agen and titanium composite models and titanium al oy material model were lower than that of medial tibia. (3) The maximum stress of medial tibia, lateral tibia and prosthesis junction:The stress distribution of col agen and titanium composite models was relatively uniform. The stress distribution of titanium al oy material model showed fluctuation. Stress concentration appeared in pal ets and prosthesis junction and the shank end of the prosthesis. The maximum stress values of lateral tibia and prosthesis junction of col agen and titanium composite models and titanium al oy material model were lower than that of medial tibia and prosthesis junction. (4) These findings showed that knee prosthesis has a certain stress shielding effect on tibia after total knee arthroplasty. The stress shielding effect of col agen and titanium composite material prosthesis was lower than titanium al oy material prosthesis, and could improve tibial incurred stress.

BACKGROUND:The degradation of a col agen Ⅰ modified porous calcium sulfate scaffold in vivo is unclear, and its degradation product effects on human osteoblasts are rarely reported.
OBJECTIVE:To observe the biocompatibility of human osteoblasts with degradation products of calcium sulfate/col agen membrane composite porous scaffold.
METHODS:Passage 2 human osteoblasts were cultured in the extract of degradation products of calcium sulfate/col agen membrane composite porous scaffold and in Dulbecco’s modified Eagle’s medium containing 10%newborn calf serum. At days 1, 3, 5, 7, cellproliferative curves and total protein were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method and Coomassie bril iant blue micro-plate method, respectively. And alkaline phosphatase activity was also detected.
RESULTS AND CONCLUSION:The proliferation rate of human osteoblasts in the extract of degradation products of calcium sulfate/col agen membrane composite porous scaffold was slightly higher than that in the Dulbecco’s modified Eagle’s medium containing 10%newborn calf serum, but there was no significant difference (P>0.05). Alkaline phosphatase activity, total protein synthesis and alkaline phosphatase/total protein were increased with time in the two groups, but there was no significant difference at different time (P>0.05). These findings indicate that the degradation products of calcium sulfate/col agen membrane composite porous scaffold cannot influence proliferation and growth of human osteoblasts as wel as their normal physiological functions, which have good biocompatibility.

AIM: To study the effect of changing left ventricular afterload and isolated perfused rabbit heart on ventricular refractory period measured by subhthreshold conditioning train stimulation (St).METHODS:Ventricu- lar refractory pened strength- interval relation was measured by St method under the condition of changine left ven- tricular afterload and elimination action of nervous and body fluid.RESULTS: Reducing left ventricular afterload pro -longed ventricular refractory period measured by St method (P

Objective To evaluate the role of neuropeptide Y2 receptor (NPY2R) in neuropathic pain (NP) in rats.Methods Thirty-six adult male Sprague-Dawley rats,aged 8 weeks,weighing 190-210 g,were randomly divided into 3 groups (n =12 each):sham operation group (group S),group NP and NPY2R antisense ohgonucleotide group (group ODN).NP was induced by chronic constrictive injury (CCI).5 μg/μl NPY2R antisense oligonucleotide 30 μl was injected intrathecally 7 days after CCI in group ODN.While normal saline 30 μl was injected intrathecally in group S.The mechanical paw withdrawal threshold and cold allodynia were measured 3 days before CCI (T0,baseline),7 days after CCI (T1) and at 15 min,1.5,3.0,4.5 and 6.0 h after intrathecal injection (T2-6).The animals were then sacrificed after the last measurement and the lumbar segment of spinal cord was removed for determination of the expression of NPY2R and calcitonin gene-related peptide (CGRP) and co-expression of NPY2R with CGRP in spinal dorsal horn neurons (by immuno fluoresceence).Results Compared with group S,the mechanical paw withdrawal threshold was significantly decreased and cold allodynia was increased at T1-6,and the expression of NPY2R and CGRP and co-expression of NPY2R with CGRP in spinal dorsal horn neurons was up-regulated in NP and ODN groups (P ＜ 0.05).Compared with group NP,the mechanical paw with-drawal threshold was significantly increased at T3-5,and the expression of NPY2R and co-expression of NPY2R with CGRP in spinal dorsal horn neurons was down-regulated (P ＜ 0.05),and no significant change was found in cold allodynia and the expression of CGRP in spinal dorsal horn neurons in ODN group (P ＞ 0.05).Conclusion NPY2R in the spinal cord dorsal horn is involved in the maintenance of mechanical hyperalgesia,but not in the maintenance of clod hyperalgesia in rats.

BACKGROUND:There are objections to the efficacy and safety of total hip arthroplasty and artificial femoral head arthroplasty in the treatment of femoral neck fracture.
OBJECTIVE:To assess the efficacy and safety of one-stage total hip arthroplasty and femoral head arthroplasty for > 60-year-old patients with femoral neck fractures.
METHODS:According to the search strategy of Cochrane colaboration network, we searched PubMed (1966 to December 2014), EMbase (1974 to December 2014), Cochrane Library (Issue 3, 2011), China Biology Medicine database(1978 to December 2014), China National Knowledge Infrastructure (1994 to December 2014), VIP database (1989 to December 2014), and Wanfang Database (1979 to December 2014). Twenty-one articles on total hip arthroplasty and hemiarthroplasty for elderly femoral neck fractures were included. Two reviewers independently evaluated the quality of the included studies and extracted the data. In case of disagreement, settlement was made by negotiation. Meta-analysis was performed by RevMan 5.0 software in the included studies.
RESULTS AND CONCLUSION:(1) Literature analysis: five randomized controled studies, three quasi-randomized controled studies, and thirteen retrospective cohort studies were included, containing 2 250 patients. (2) Meta-analysis: No significant differencein rate of dislocation, deep infection rate and mortality rate in 1 year after replacement was detected between total hip arthroplasty and hemiarthroplasty for elderly femoral neck fractures (dislocation rate:RR=1.38, 95%CI: 0.81-2.34; deep infection rate RR=1.12, 95%CI: 0.60-2.11; mortality rateRR=0.90, 95%CI: 0.69-1.18). Reoperation rate was higher in the hemiarthroplasty group than in the total hip arthroplasty group (RR=0.46, 95%CI: 0.32-0.66). Harris score on the affected side between1 and 4 years was significantly higher in the total hip arthroplasty group than in the hemiarthroplasty group (MD=5.64, 95%CI: 2.82-8.46). (3) Results suggested that if physical conditions permit, compared with hemiarthroplasty group, femoral neck fractures patients aged > 60 years old in the total hip arthroplasty group had better hip function, but no significant difference was found in dislocation, deep infection and mortality between both groups.

Objective To discuss the efficacy of a modified single posterior fixation of complicated acetabular fractures with a percutaneous cannulated screw and a reconstruction plate in comparison with traditional bilateral approaches (ilioinguinal and Kocher-Langerbeek). Methods From April 2004 to May 2007, 48 cases of complicated acetabular fracture were treated surgically. By Letoumel classification, 22 were transverse and posterior wall fractures, 16 fractures of both columns, 3 fractures of anterior column and posterior wall, 3 T shape fractures and 4 anterior column and posterior hemi-transverse fractures. Of them, 22 cases were treated through the bilateral approaches and 26 cases through the modified single posterior approach by which a percutuneous cannulated screw was applied, going askew through skin and ischial tuberosity, to fix the anterior column and a reconstruction plate to fix the posterior column. Results Forty patients were followed up for 6 to 37 months(average, 18 months) . There was no statistical difference between the 2 groups as fax as the following factors were concerned: anatomic reduction rate and functional good-to-excellent rate. But there were significant differences in operation time and volume of hemorrhage during operation. Conclusion In treatment of complicated acetabular fractures, the modified singl eposterior approach simplifies traditional bilateral approaches so that surgery procedures, perioperative bleeding and postoperative complications can be reduced without sacrificing the treatment efficacy.

Objective:To investigate the inhibitory effect of dihydroartemisinin on non-small cell lung cancer H1299 cells.Methods:Through the CCK-8 method for determining the IC 10 of dihydroartemisinin ,choose low dose IC 10 as the experimental concentration,CCK-8 to observe artemisinin in low doses of H1299 cell proliferation, cycle and the influence of radiation sensitivity.Results:IC10 of dihydroartemisinin was 14.87 μmol/L,dihydroartemisinin could inhibit proliferation of H 1299 cells,slow down the cell cycle , and increased the radiation sensitivity.Conclusion: Dihydroartemisinin can inhibit cell proliferation , cell cycle arrest in S phase ,increase the radiation sensitivity.

BACKGROUND:As an oral anticoagulant drug, many experiments have proved that rivaroxaban can prevent the deep venous thromboembolism after the hip arthroplasty. The foreign literatures indicate that it can significantly reduce the incidence of deep venous thromboembolism after extending the treatment course to 35 days. But there is no significant conclusion at home, and the safety of drugs after extentding the course has not been confirmed. OBJECTIVE:To analyze the efficacy and safety of rivaroxaban versus low-molecular-weight heparin for the prevention of deep venous thrombosis after the hip arthroplasty. METHODS:106 patients with primary unilateral hip arthroplasty in the Second Clinical Medical College of Shanxi Medical University between March 2011 and September 2012 were selected. The patients were randomly divided into rivaroxaban group and low-molecular-weight heparin group. The patients in two groups were given drugs at 6 hours after replacement, the patients in the rivaroxaban group were given rivaroxaban 10 mg/d with the course of 5 weeks;the patients in the low-molecular-weight heparin group were given low-molecular-weight heparin 4 100 U/d with the course of 2 weeks. RESULTS AND CONCLUSION:The review and fol ow-up results showed there was no deep vein thrombosis or symptoms of deep vein thrombosis in patients of the rivaroxaban group after replacement, while seven cases (13%) of deep vein thrombosis were observed in the low-molecular-weight heparin group, and there was significant difference in the incidence rate of deep vein thrombosis between two groups (P<0.05). There were no significant differences in venous blood hemoglobin level, platelet level and coagulation function before and after replacement, as wel as the drainage volume and subcutaneous ecchymosis area after replacement of the patients received unilateral hip arthroplasty between two groups (P>0.05). The results indicate that ful course of rivaroxaban has clear effect and reliable security in the prevention of deep venous thrombosis after hip arthroplasty.

BACKGROUND:Nowadays, the internal fixation materials for the clinical treatment of unstable femoral intertrochanteric fractures are broadly divided into two categories:intramedul ary fixation system and
extramedul ary fixation system. However, the effects of the treatments usual y lack of macro evaluation.
OBJECTIVE:To compare the effect of intramedul ary fixation system and extramedul ary internal fixation system in the treatment of unstable femoral intertrochanteric fractures.
METHODS:217 patients with unstable femoral intertrochanteric fracture (Evans typing: Ⅲ type to Ⅴ type and R type) were treated by using intramedul ary fixation system and extramedul ary internal fixation system:18
cases were treated with dynamic condylar screw, 67 cases were treated with dynamic hip screw, 43 cases were treated with reconstruction nail, 72 cases were treated with proximal femoral anti-rotation blade nail, and 17 cases were treated with new generation of antegrade interlocking intramedul ary nail. The operative time, length of
incision, blood loss, time in bed, fracture healing time, complications and Harris hip score were analyzed and compared.
RESULTS AND CONCLUSION:In the aspects of operative time, blood loss, time in bed, complications and
Harris hip score, the intramedul ary fixation system was superior to extramedul ary internal fixation system. But there were significant differences in the aspects of length of incision and fracture healing time between two
methods. The results showed that the treatment of unstable femoral intertrochanteric fractures by using
intramedul ary fixation system was better than the extramedul ary internal fixation system, as the intramedul ary fixation system could effectively shorten the operative time and reduce blood loss. This stable and reliable fixation enables patients to take early postoperative functional exercise, and could significantly shorten the time in bed and reduce the incidence of complications and it is conducive to postoperative hip function recovery.
Therefore, intramedul ary fixation system is an ideal method for the treatment of unstable femoral intertrochanteric fractures.

AIM:To study the effects of changing right heart load on electrophysiologic parameters in anesthetized dogs. METHODS:Change of right atrial and ventricular load, right atrial and ventricular diastolic threshold (ADT, VDT), right atrial and ventricular relative refractory period (ARRP,VRRP) and right atrial and ventricular effective refractory period (AERP, VERP) were recorded. RESULTS: Increasing right heart load step by step(grade A and B) caused prolongation of ARRP, AERP, VRRP (grade B, P