Biomechanical Analysis and Optimization of Minimally Invasive Pelvic Internal Fixation / 医用生物力学

Objective By comparing biomechanical properties of two-screw rod and three-screw rod for fixing pelvic fracture, the difference in mechanical effects of different screw rod fixation positions in pelvic minimally invasive surgery was studied.Methods The mechanical models of pelvis fixed by two-screw rod and three-screw rod were established, and biomechanical characteristics of the pelvis during standing on both legs, during single-legged standing on healthy side or affected side, as well as in sitting posture were compared and analyzed by finite element simulation, and the fixation effect of three-screw rod was verified by clinical experiments.Results Both fixation methods could restore mechanical transmission of the pelvis. But for three-screw rod fixation, the stress on both sides of the pelvis was more balanced, and the displacement of the whole body and fracture surface was also lower during single-legged standing.Conclusions The three-screw rod fixation has an excellent effect in stability, which is more beneficial for fracture recovery.

Application of an innovational hybrid simulation-based education of bone traction with co-Debriefer for medical students / 中华医学教育探索杂志

Objective:To develop an innovational hybrid simulation-based education of bone traction with co-Debriefer for medical students and to evaluate its effectiveness.Methods:This study was designed as a cross-controlled study. From June 2018 to June 2019, 28 medical students were randomized into two groups. The two groups adopted simulation-based education and traditional teaching method respectively. In the second week of internship, the teaching methods of the two groups exchanged. Scores rating of the skill were used to assess the students' performance in the end of each teaching methods. SPSS 23.0 software was used to analyze the collected data.Results:In the first weekend of orthopedic-internship, students in the experimental group scored significantly higher than the control group, with an average score of 85.07 points versus 67.92 points. In the second weekend of practice, there was no obvious change in the skill score of the experimental group, but the score of the control group was significantly improved, and there was no obvious difference with the experimental group.Conclusion:The hybrid simulation-based education with co-debriefing is a reliable teaching method for medical interns to learn skills of bone traction, which can effectively help improve students' skills, reduce their errors, and ensure patient's safety.

Research advances in the mechanism of osteoarthritis caused by the mechanical instability / 上海交通大学学报（医学版）

Osteoarthritis is a common articular cartilage degenerative disease and the main cause is mechanical instability. The mechanical instability can reduce the number of chondrocytes and destroy extracellular matrix through direct injury, inducing cell apoptosis, and stimulating the production of inflammatory factors, leading to decrease of matrix typeⅡ collagen and proteoglycan and degeneration of cartilage. Long-term cartilage degeneration can result in osteoarthritis. Therefore, understanding how mechanical instability leads to the incidence of osteoarthritis can better improve the course of osteoarthritis from the perspective of mechanics.

Effects of different growth factors on the antioxidant capacity of endplate chondrocytes / 中国组织工程研究

BACKGROUND:It is wel-known that vitamin E holds antioxidant capacity, but whether other growth factors have the same effect on endplate chondrocytes has not yet been reported. OBJECTIVE:To observe the effect of different growth factors on the antioxidant ability of endplate chondrocytes in the intervertebral disc. METHODS:Endplate chondrocytes were primary cultured, and then divided into four groups, including blank control, serum deprivation, hydrogen peroxide stimulation and hydrogen peroxide stimulation combined with different growth factors groups. The 4th group was subdivided into insulin-like growth factor-1, basic fibroblast growth factor, transforming growth factorβ, forskolin and vitamin E groups. The expression levels of caspase-3, matrix metal oproteinase 13 and 3, inhibitor of metal oproteinase 1 as wel as thrombin 4 and 5 were detected by real-time PCR. Cel apoptosis was analyzed through apoptosis kit and flow cytometry. Cel synthesis and secretion were detected by western blot assay. The total antioxidant capacity and the hydrogen peroxide content were determined by kit, and then statistical y analyzed. RESULTS AND CONCLUSION:Different growth factors had significant differences in the endplate chondrocyte apoptosis, secretion and antioxidant capacity. To conclude, transforming growth factorβand forskolin do further damage to the cel s stimulated by hydrogen peroxide, while insulin-like growth factor-1 and vitamin E expose protective effect on the injured cel s.

Anterior subcutaneous internal fixation with triple pedicle screws for treatment of Tile type B pelvic fractures / 中华创伤杂志

Objective To evaluate the clinical outcome of anterior subcutaneous internal fixator (ASIF) system with triple pedicle screws in stabilizing Tile type B pelvic fractures.Methods From August 2013 to April 2015,38 cases of pelvic fractures were stabilized with the ASIF system using triple pedicle screws.There were 24 male and 14 female cases,with the age range of 16-74 years [(41.5 ±5.5) years].Causes of injury were traffic accidents (n =28),crushing injury (n =6) and fall from height (n =4).All cases had Tile type B fractures,including 5 cases of type B1,29 type B2 and 4 type B3.Intraoperative blood loss,operation time,length of hospitalization and complications were detected.Postoperative function evaluation was done using the Majeed score.Results All cases were available for follow-up of 6.5-13.5 months (mean,10.5 months).Intraoperative blood loss was (30.8 ± 7.1)ml,operation time was (51.5 ± 9.2) minutes,and length of hospitalization was (5.0 ± 3.1) days.Among them,34 cases showed bilateral hip flexion over 95 degrees after operation,and 24 cases were able to squat fully 1.5 months after operation.No cases experienced nonunion,delayed union,superficial or deep surgical wound infection,urethral injury and dysuresia.Two cases developed temporary lateral femoral cutaneous nerve numbness.According to the Majeed score,excellent results were found in 32 cases (84％) and good results in 6 cases (16％).Conclusion ASIF system with triple pedicle screws results in high healing rate and few complications in the treatment of Tile type B pelvic fractures,and hence deserves popularization in clinic.