Finite element analysis of anterior ring injuries in unstable pelvic fractures treated by different methods / 中国骨伤

OBJECTIVE@#To compare the biomechanical stability of different fixation methods for anterior ring injury of unstable pelvic fractures, and to provide reference for clinical treatment.@*METHODS@#An unstable pelvic fracture model (Tile C) with one side of the sacroiliac joint dislocation and the pubic rami fracture was constructed via three-dimensional finite element analysis. Five different fixation methods were used in the front, and the rear was fixed with sacroiliac screws. The von Mises stress and strain distributions of different combinations of fixation methods were analyzed under mimicking standing conditions.@*RESULTS@#After being loaded with 500 N vertically, the maximum stress in the anterior fracture was 3.56 MPa in anterior pelvic external fixation (AEF) group, the total displacement and the vertical displacement of the Y axis at the sacroiliac joint and the fracture were not more than 1.5 mm. The maximum stress at fixation, the front of the fracture and sacroiliac joints in the anterior pelvic subcutaneous approach(APA) group and AEF, was significantly higher than anterior modified Stoppa approach(ASA) group, anterior pelvic Ilioinguinal approach (AIA) group, and canulated screw fixation(CSF) group. The total displacement and the vertical displacement of the Y axis at the sacroiliac joint and the fracture in APA group and AEF group were also greater than the other three groups.@*CONCLUSIONS@#Anterior ring injury of unstable pelvic fractures can be significantly improved after the fixation of the implants in the five combined methods. However, overall biomechanical properties of ASA, AIA and CSF group are superior to APA and AEF group.

Effect of perioperative dexamethasone on nausea, vomiting and pain after total knee arthroplasty / 中国骨伤

OBJECTIVE@#To investigate the effect of perioperative dexamethasone on nausea, vomiting and pain after unilateral total knee arthroplasty and to evaluate its safety.@*METHODS@#From February 2014 to June 2016, 100 patients with unilateral advanced osteoarthritis treated by total knee arthroplasty were divided into two groups: 50 patients in dexamethasone group including 27 males and 23 females, aged (72.30±7.02) years, were given intravenous drip of dexamethasone 10 mg before operation; 50 patients in saline group, including 26 males and 24 females, aged (71.30±6.08) years, were given the same amount of saline at the corresponding time. The VAS scores of pain at rest and at 45 degrees of knee flexion were recorded at 2, 4, 6, 8, 12, 24, 36 and 48 h after operation. Vomiting, antiemetic drugs and opioids were recorded at 0 to 24 h and 24 to 48 h after operation. The side effects and complications were recorded.@*RESULTS@#All the 100 patients were followed up for an average of 14.5 months. VAS score of pain at rest in dexamethasone group was lower than that in saline group at 8, 24 and 48 h after operation (<0.05); VAS score of dexamethasone group at 45 degrees after knee flexion was lower than that of saline group at 8 and 48 h after operation(<0.05); VAS score of dexamethasone group at rest and 45 degrees after knee flexion was lower than that of saline group(<0.05). The dosage of opioids and total opioids in dexamethasone group was lower than that in saline group at 0 to 24 h, 24 to 48 h after operation (<0.05). The proportion of nausea and vomiting occurred at 0 to 24 h and 24 to 48 h after operation, and the proportion of antiemetic required at 0 to 24 h after operation had statistical significance between two groups(<0.05). The total antiemetic dosage of dexamethasone group was less than that of saline group(<0.05). As of the last follow-up, no complications such as infection, gastrointestinal ulcer and bleeding occurred in the two groups.@*CONCLUSIONS@#Preoperative systemic application of dexamethasone can effectively reduce pain and nausea and vomiting after TKA without increasing postoperative complications.