BACKGROUND:The traditional view is that proximal fibular fractures do not require fixation.Others and our research suggest that the proximal fibular structure plays an important role in the stability of the posterolateral structure of the knee joint,and its mechanism of action is worth studying. OBJECTIVE:To investigate the biomechanical effects of proximal fibular fractures on various structures of the knee joint in an extended state. METHODS:Finite element method was used to conduct simulated biomechanical experiments.A healthy young male volunteer was selected to establish a finite element model of the knee joint in an extended state using MRI and CT image data,and four proximal fibular shapes were simulated(Model A:intact,Model B:1 cm fracture below the fibular head,Model C:1 cm tip defect fracture from the proximal end of the fibula to the distal end,and Model D:2 cm bone defect from the proximal end of the fibula).A longitudinal concentrated load of 1 500 N was applied to the femoral shaft to compare and analyze the distribution and changing trend of the maximum equivalent stress and maximum first principal stress of each structure of the knee joint in an extended state under four working conditions. RESULTS AND CONCLUSION:(1)In Model A,the maximum equivalent stress in the tibial cartilage and lateral compartment of the meniscus was greater than that in the medial compartment,while the maximum first principal stress in the tibial plateau and medial compartment of the meniscus was greater than that in the lateral compartment.The maximum equivalent stress of the medial condyle of the femoral cartilage was greater than that of the lateral condyle,and the maximum first principal stress of the medial condyle of the femoral cartilage was greater than that of the medial condyle.(2)Compared to Model A,there was no significant difference in the magnitude and distribution of the maximum equivalent stress and maximum first principal stress in the cartilage and meniscus of Model C.(3)Compared to Model A,the maximum equivalent stress increase amplitude of Model B was in the order of medial tibial cartilage(14.9％),medial condyle of femoral cartilage(13.6％),and medial meniscus(6.6％).The maximum first principal stress increase amplitude was the medial meniscus(11.06％),the medial tibial cartilage(8.65％),and the medial condyle of the femoral cartilage(7.46％).The maximum equivalent stress increase amplitude of the ligament was as follows:popliteal arch ligament(33.2％)>anterior cruciate ligament(21.3％)>fibular collateral ligament(17％)>posterior cruciate ligament(14.3％)>anterior lateral collateral ligament(13.2％)>medial collateral ligament(10.1％).(4)Compared to Model A,the maximum equivalent stress increasing trend of Model D followed the medial tibial cartilage(19.5％),femoral cartilage medial condyle(17.9％),and medial meniscus(9.9％).The maximum first principal stress in sequence was the medial meniscus(14.04％),the medial tibial cartilage(13.03％),and the medial condyle of the femoral cartilage(11.37％).The increasing trend of maximum equivalent stress in ligaments was as follows:anterior cruciate ligament(25.2％)>posterior cruciate ligament(18.9％)>medial collateral ligament(18.5％)>anterior lateral collateral ligament(12.7％).(5)It is suggested that when the knee joint is extended,a 1 cm fracture below the fibular head and a 2 cm fibular tip bone defect have a significant impact on the structure of the medial ventricular cartilage,anterior cruciate ligament,and posterior lateral ligament complex.

Objective To investigate the effects of three-dimensional(3D)screws and circular plates on the biomechanical stability of Sanders ABⅢ calcaneal fractures.Methods Calcaneal computed tomography(CT)and magnetic resonance imaging(MRI)data from a 26-year-old volunteer were collected to establish a 3D finite element model of Sanders ⅢAB calcaneal fracture fixed with 3D screws and circular plates.A longitudinal load of 700 N was applied to compare the variations in the stress,displacement of the bone block,and internal fixation in the different models.Results Under 700 N longitudinal loads,the maximum displacement of the bone block and the maximum stress of the bone block and internal fixation were concentrated at the intersection of the posterior talar articular plane internal fixation and fracture line.The overall displacements of the bone blocks in the 3D screw and circular plate models were similar.Compared with the circular plate model,the maximum and average stresses of the bone block and internal fixation in the 3D screw model were lower,and the displacement and stress changes of the 3D screw model were closer to those of the complete calcaneal bone model.Conclusions In the fixation of Sanders ⅢAB calcaneal fractures,both 3D screw and circular plate fixation method can provide good stability.The biomechanical properties of the 3D screws were better than those of the circular plates,which is consistent with the biomechanical characteristics.

Objective:To investigate the clinical effect of Dynamic neutralization system applied to the treatment of lumbar degenerative diseases with fatty infiltration of multifidus muscle.Methods:From Jan 2015 to Dec 2017, a total of 53 patients of lumbar degenerative diseases with multifidus fatty infiltration treated by Dynesys in our hospital were analyzed, included 21 males and 32 females, aged 66.2±7.4 (range 48-81) years. There were lumbar spinal stenosis in 37 casesand lumbar disc herniationin 16 cases; the index level included L 2-S 1 in 3 cases, L 3-S 1 in 13 cases, L 2-L 5 in 5 cases, L 4-S 1 in 17 cases, and L 3-L 5 in 15 cases. The pedicle screws were inserted at the point of intersection of the outer edge of superior articular process and the midline of transverse process. After discectomy of herniated disc and hyperplastic ligamentum flavum, the distance between the upper and lower pedicle screws was measured and then the spacer of the corresponding length was cut out. Finally, the spacer was placed and fixed between the upper and lower pedicle screws by the elastic rope. The degree of multifidus fat infiltration, lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slop (SS), range of motion (ROM), intervertebral height (IH), Japanese Orthopaedic Association (JOA) score, Oswestry disability index (ODI), the MOS 36-item short-form health survey (SF-36) and visual analog scale (VAS) were evaluated postoperatively. Results:The operation was performed successfully in all the patients. The operation duration was 173.5±64.7 (range 125-240) min. Intraoperative blood loss was 469.5±118.2 (range 380-620) ml. The patients were followed up for 47.9±6.7 (range 38-62) months averagely. At the last follow-up, the degree of fatty infiltration of the multifidus muscle showed no further progress by MR scan. There was no significant difference in ROM and IH at different time points preoperativelyand postoperatively. The LL recovered from 37.6°±8.8° to 43.2°±9.1°, the PT decreased from 24.7°±9.3° to 20.5°±5.1°, and the SS increased from 22.1°±7.7°to 26.3°±8.0°. The JOA score increased from preoperative 6.4±1.2 to 20.6±2.8, ODI decreased from preoperative 50.6%±11.3% to 13.0%±3.4%, SF-36 increased from preoperative 81.5±3.6 to 95.5±4.2, and the VAS decreased from preoperative 4.2±1.0 to 1.1±0.6. One patient experienced loosening and displacement on the left side pedicle screw of the L2 vertebral body 3.5 years after operation, and herclinical symptom improved significantly after conservative treatment.Conclusion:Dynesysis is safe and effective for the treatment of lumbar degenerative diseases with fatty infiltration of multifidus muscle, and it can restore the complete structure and function of tension band at lower back and prevent the progress of multifidus muscle fat infiltration combined with postoperative rehabilitation training.

Objective To investigate the effect of medial collateral ligament (MCL) repair and coronoid process fracture fixation on stability of the Terrible Triad of the elbow. Methods CT and MRI scan images of elbow joints from one healthy 28-year-old male volunteer were used to establish three elbow models. Model A: normal model. Model B: repair of coronoid process fractures, without MCL repair. Model C: repair of MCL, without repair of ulnar coronoid processes. Longitudinal loads were applied on the three models to analyze the displacement and stress distributions of the elbow joint under different working conditions and compare the stability of the elbow joint. Results The displacement and stress distributions of the three models were similar. The maximum displacement and maximum stress of the articular surface were located at the ulna pulley notch, while the minimum displacement was located at the coronoid process and its medial side. The minimum stress was located at the lower lateral side of the coronoid process. There were no statistical differences in the maximum displacement and stress among the three models (P>0.05). Conclusions When the lateral column is stable, the effect of repairing the MCL and fixing the fracture block of ulnar coronoid process is similar.

Objective To assess the safety and efficacy of hypertonic saline in traumatic hypovolemic shock with Meta-analysis.Methods Comprehensive electronic search strategies were developed using the following electronic databases:PubMed,EMBASE,Medline,Ovid、Clinical Trials,CNKI,Wan Fang,CBM and FMJS.The Literature published before August of 2017 was searched.The randomized controlled trials (RCTs) about hypertonic saline in traumatic hypovolemic shock were included.A data-extraction sheet was developed based on the preset standards.The data from eligible studies were pooled through Meta-analysis.Results 9 trials with a total of 1600 patients (741cases in observation group,859 cases in control group) met the inclusion criteria.The meta-analysis showed that the hypertonic saline group displayed remarkable increase in the systolic blood pressure and decrease in hemoglobin level,compared with the isotonic saline group [MD =6.43,95％ CI(1.16,11.70),P ＜0.05],[MD =-5.99,95％ CI (-9.04,-2.95),P ＜0.05].The level of serum sodium [MD =7.94,95％ CI(7.39,8.50),P ＜0.05],serum chloride [MD =9.67,95 ％ CI(8.77,10.57),P ＜ 0.05] and osmolality [MD =18.11,95％ CI (10.73,25.49),P ＜ 0.05] in the hypertonic saline group was increased significantly but acceptable.No significant difference in mortality was found between the hypertonic saline group and the isotonic saline group [OR =0.88,95％ CI(0.69,1.11),P ＞ 0.05].Conclusions Available evidence shows that small volume hypertonic Sodium Chloride saline is safe and effective for resuscitation in patients with traumatic hemorrhagic shock.Since the quality of the inclued studes were not high,more high-quality,multicenter randomized controlled clinical studies need to provide better evidence for the above conclusion.

BACKGROUND: The extramedulary fixation system including dynamic hip screw (DHS) is commonly used in treatment of Intertrochanteric fracture. However, in patients with unstable intertrochanteric fracture, extramedulary fixation system often leads to the failure of fracture fixation. Intramedulary fixation system including both proximal femoral nail antirotation (PFNA) and InterTan nail has been widely used in the treatment of unstable intertrochanteric fractures. OBJECTIVE:To compare the therapeutic effects of extramedulary fixation system containing DHS, PFNA and InterTan nail in the treatment of intertrochanteric fracture. METHODS:Literatures were searched in Wanfang, PubMed, Embase, Medline, the Cochrane library to screen literatures published from January 1990 to November 2014. Relevant studies addressing extramedulary fixation system containing DHS, PFNA and InterTan nail were screened. RESULTS AND CONCLUSION: 346 articles were screened, and 13 of them were in accordance with the inclusion criteria. 1 271 patients with different types of intertrochanteric fracture were assessed in this study. Compared to DHS group, patients treated with PFNA and InterTan nail had shorter operation time and less blood loss. No significant difference in rehabilitation time and Harris score was detected among three kinds of fixation methods. Additionaly, PFNA and InterTan nail had a similar effect. These findings verify that compared with DHS, PFNA and InterTan nail can optimize the surgery, but cannot elevate postoperative outcomes.

BACKGROUND:Repair programs of posterolateral tibial plateau fracture included posterior plate screws, lateral plate screw and anterior and posterior lag screw fixation. To choose which fixation methods depends on clinical experiences of physicians. Study results are mainly clinical reports, and lack of mechanical evidence.
OBJECTIVE:To compare biomechanical changes in three fixed manners (lateral plate screw group, posterior plate screw group and anterior and posterior lag screw group) in the repair of posterolateral fracture of tibial plateau from the angle of biomechanics.
METHODS:A total of tibial specimens of six adult male antisepsis corpses (12 samples) were used for measuring bone mineral density of metaphysis. 1/2 posterolateral tibial plateau fracture model was established by electric pendulum saw. The model was randomly divided into three groups:lateral plate screw group, posterior plate screw group and anterior and posterior lag screw group. Finite element method and biomechanics were used to test axial displacement value and the maximal displacement distribution area under the axial loads of 250, 500, and 1 000 N.
RESULTS AND CONCLUSION:There was no significant difference in average bone density in three groups of metaphysis (P>0.05). The minimum axial displacement of the fracture fragments was in the anterior and posterior lag screw group (0.013 521 mm), fol owed by posterior plate screw group (0.016 991 mm), and the maximum was visible in the lateral plate screw group (0.138 200 mm) under 250 N load. Displacement value was similar to the 250 N under 500 and 1 000 N. According to the results of biomechanics, displacement values of anterior and posterior lag screw was obviously less than the lateral plate screw group and posterior plate screw group (P<0.05). There was no significant difference between the lateral plate screw group and posterior plate screw group (P>0.05). The maximal displacement distribution area was proximal tibiofibular joint border zone in two methods. These data indicated that the biomechanical stability was most advantageous in the anterior and posterior lag screw group, and poorest in the lateral plate screw group. In the clinic, anterior and posterior lag screw fixation can be used as a first choice for repair of posterolateral tibial plateau fracture.

BACKGROUND:It remains controversial in term of efficacy for the lightweight mesh and heavyweight mesh in inguinal hernia repair.
OBJECTIVE:To compare the clinical therapeutic effects of lightweight mesh and heavyweight mesh in open methods of inguinal hernia repair with Meta-analysis.
METHODS:Comprehensive electronic search strategies were developed using the fol owing electronic databases:PubMed, Cochrane Library, EMBASE, Medline, Ovid, CNKI, VIP, Wanfang and FMJS. The Literature published before February 2013 was searched. The randomized control ed trials about comparing lightweight mesh and heavyweight mesh in open methods of inguinal hernia repair were included. A data-extraction sheet was developed based on the preset standards. The data from eligible studies were pooled using RevMan5.1 software through Meta-analysis.
RESULTS AND CONCLUSION:Eighteen trials with a total of 4 450 hernias met the inclusion criteria. The meta-analysis showed that there was a statistical difference between lightweight mesh group and the heavyweight mesh group on short-term pain [odd ratio (OR)=0.57, 95%confidence interval (CI) (0.43, 0.74), P<0.05] and a reduced risk of developing foreign body sensations [OR=0.49, 95%CI (0.35, 0.69), P<0.05]. No significant differences were found between the two groups in recurrence rate, testicular atrophy, seroma, hematoma, wound infection, urine retention (P>0.5). According to limited evidence, there are some findings as fol ows:the lightweight mesh is of feasibility, safety and effectiveness for inguinal hernia repair. Because of the limits of sample and quality, more large-sample and high-quality trials are required to make a definite clinical evidence to use lightweight mesh for inguinal hernia repair.

BACKGROUND:Patients with elder hip fracture has more complications, poor affordability and high perioperative risk, so the preoperative ful preparation and evaluation are needed.
OBJECTIVE:To predict the accuracy of the prognosis of elderly patients with hip fracture through comparing the difference between American Society of Anesthesiologists score and Daping orthopedics operation risk scoring system for senile patients.
METHODS:A retrospective study was performed on 300 cases with elderly hip fracture selected from January 2011 to December 2012 from Department of Orthopedics, Gongli Hospital of Pudong. American Society of Anesthesiology score and Daping orthopedics operation risk scoring system for senile patients were conducted before treatment, and the predictive values of two scoring systems on the incidence of complications and mortality were compared.
RESULTS AND CONCLUSION:According to the American Society of Anesthesiology score and Daping orthopedics operation risk scoring system for senile patients, 148 cases and 97 cases had complications respectively. On the contrary, the actual number of complications was 89. The former predicted value was significantly higher than the actual value, and there was no significant difference between the latter forecast value and the actual value. The numbers of death predicted by American Society of Anesthesiology score and Daping orthopedics operation risk scoring system for senile patients were 27 cases and six cases, but the actual number of death was three cases, indicating that former predicted value was significantly higher than the actual value, and there was no significant difference between the latter predicted value and the actual value. The American Society of Anesthesiology score has a certain errors in predicting the postoperative complications and mortality of patients with elderly hip fractures, but it is simple and useful in clinic. The Daping orthopedics operation risk scoring system for senile patients can accurately evaluate elderly hip fracture operation risk, and can predict the postoperative complications and mortality more objective when compared with the American Society of Anesthesiology score.

BACKGROUND:Proximal humeral internal locking system fixation for complex humeral fractures via deltoid splitting approach provides good clinical results, but certain complications stil existed.
OBJECTIVE:To explore the postoperative complications and the related risk factors for displaced three-part and four-part fractures of proximal humerus treated with proximal humeral internal locking system fixation via deltoid-splitting approach, and to propose the corresponding countermeasures.
METHODS:106 cases with displaced three-part and four-part fractures of proximal humerus were retrospectively analyzed. The relationship between postoperative complications and the related risk factors was analyzed with Logistic regression analysis.
RESULTS AND CONCLUSION:A total of 81 patients were fol owed-up for 12 to 30 months. The mean Constant score at 12 months after operation was (76.57±4.70) points. The postoperative complications occurred in 31 patients (38.3%) of which impingement syndrome involved in 16 cases (19.8%), head-shaft angle loss in six cases (7.4%), head-shaft angle loss combined with screws cut-out in two cases (2.5%), pure screws cut-out in two cases (2.5%), humeral head necrosis in two cases (2.5%), fat liquefaction in five cases (6.2%). Single factor analysis showed that there were significant differences in the superiorly located greater tuberosity, superiorly located plate and Neer classification between impingement group and un-impinged group (P<0.05). There were statistical y significant differences in age, postoperative medial cortical defects and Neer classification between head-shaft angle loss group and un-loss group (P<0.05). By means of logistic regression analysis, the superiorly located greater tuberosity, superiorly located plate and Neer classification were the individual predictors for postoperative impingement syndrome;postoperative medial cortical defect and Neer classification were the individual predictors for postoperative head-shaft angle loss.