Objective: To investigate the effects of acetabular coverage on the initial stability of the cup during total hip arthroplasty in developmental dysplasia of hip. Methods: There were 50 fourth-generation synthetic hemi-pelvises. The different cup coverage rate (100% group, 70% group, 60% group, 50% group, 40% group) was created in pelvis with 10 specimens per group. The synthetic hemi-pelvis was fixed rigidly to a customized fixture which was placed on the testing table of the material testing machine. Pull-out and torque test were conducted by computer-control in torsion testing machine. Results: In the acetabular cup pull-out test, the average pull-out force for mode of failure in 100%, 70%, 60%, 50%, and 40% group was 1 560.4±438.7, 1 467.2±349.8, 1 137.8±427.4, 737.4±134.8, 506.6±119.0 N, respectively. The pull-out force was reduced gradually. The pull-out force in 100% group was significantly higher than that in 50% (P=0.004) and 40% (P=0.001) group. The pull-out force in 70% group was significantly higher than that in 50% group (P=0.002) and 40% group (P=0.000). The force in 40% group was significantly lower than that in 60% group (P=0.013) and 50% group (P=0.021). In the acetabular cup torque test, the average torque for mode of failure in 100%, 70%, 60%, 50%, and 40% group was 28.0±3.7, 17.0±2.2, 9.4±1.1, 7.6±1.1, 6.4±1.1 N·m, respectively. The torque was reduced gradually. The torque in 100% group was significantly higher than that in other groups (P<0.05). There was no significant difference between 50% and 40% group (P>0.05). The torque in other groups were similar (P>0.05). Conclusion The present biomechanical study showed that different acetabular cup coverage rate affected the initial stability of the cup. The highest initial stability was observed in the cup with a 100% of cup coverage rate. The cup could not obtain 100% coverage when with acetabular rim defect. We should try our best to make the cup coverage reach to 70%. The 70% coverage rate has sufficient initial stability to meet daily activities without increasing the cup loosening rate.

Objective To study the efficacy and safety of ibutilide for AF and atrial flutter.Methods Thirty-two AF and atrial flutter patients with arrhythmia ≤3 months were randomly divided into ibutilide treatment group (n=17) and amiodarone treatment group (n=15).The patients in ibutilide treatment group were treated with 10 ml 5％ glucose injection containing 1 mg ibutilide,which was repeated after 10 min if it was ineffective and those in amiodarone treatment group were treated with 10 ml 5％ glucose injection containing 150 mg amiodarone,which was repeated after 10 min if it was ineffective.Results The total recovery rate of AF and atrial flutter was significantly higher in ibutilide treatment group than in amiodarone treatment group (64.7％ vs 40.0％,P＜0.05).The mean recovery time of AF and atrial flutter was significantly shorter in ibutilide treatment group than in amiodarone treatment group (29.28±12.57 min vs 70.59±16.83 min,P＜0.01).Conclusion Ibutilide can rapidly recover AF and atrial flutter with a high success rate and a reliable safety.The therapeutic effect of ibutilide is better than that of amiodarone for AF and atrial flutter.

Objective: To investigate the effect of nicorandil on ventricular arrhythmia in patients with acute ST-segment elevation myocardial infarction (STEMI) treated with emergent percutaneous coronary intervention (PCI). Methods: A total of 120 acute STEMI patients treated with emergent PCI in our hospital from January 2015 to June 2016 were randomly divided into control group and experiment group (n=60 each). Patients in both groups received conventional therapy.Patients in experiment group took 10 mg nicorandil orally before PCI and received oral nicorandil treatment (15 mg/d, three times daily) for 3 days.QT disperse(QTd), correct QTd(QTcd) and the occurrence rate of ventricular arrhythmia were compared between two groups. Results: QTd at 6, 24, 48 and 72 hours((70.6±4.4), (67.2±5.3), (55.7±8.5), (48.2±8.2) ms, respectively) after PCI was significantly lower in the experiment group than those of control group ((77.1±7.1), (71.3±6.5), (65.1±8.1), (57.2±5.4) ms, all P<0.05). The level of QTd was also significantly lower in the experiment group at 6, 24, 48 and 72 hours((77.5±7.7), (67.7±8.6), (61.2±7.5), (52.9±8.4) ms, respectively) after PCI comared to those of control group ((88.6±8.1), (79.2±7.8), (74.4±7.4), (69.6±8.6) ms, all P<0.05). There was no significant difference in the incidence of reperfusion arrhythmia during PCI procedure between the two groups.The prevalence of the ventricular premature beat in the experiment group (25/60, 41.7%) was significantly lower than in the control group(45/60, 75.0%) within 3 days after PCI(P<0.01), the prevalence of the no sustained ventricular tachycardia and ventricular fibrillation in the experiment group(6/60, 10.0%) was also significantly lower than in the control group (18/60, 30.0%, P<0.01) within 3 days after PCI. Conclusions Nicorandil use prior and post PCI could decrease the occurrence rate of ventricular arrhythmia in STEMI patients undergoing emergent PCI, and this effect might be related with reduced QTd and QTcd post medication.