BACKGROUND:With the continuous progress of science and technology,the introduction of new technologies and methods will bring more possibilities and new breakthroughs for the application of shape memory alloys in the fields of assistive and rehabilitation. OBJECTIVE:To review the application status of shape memory alloys in assistive and rehabilitation equipment,discuss their main methods,techniques and results,summarize and put forward suggestions,hoping that shape memory alloys can be continuously optimized and bring more new changes for the development of assistive and rehabilitation equipment. METHODS:WanFang,PubMed,and Web of Science databases were searched by computer."Shape memory alloys,application progress,orthodontics,orthopedic,prosthesis,rehabilitation,properties,implantation,mechanical properties,nickel-titanium memory alloys,actuation"were used as Chinese search terms."Shape memory alloys,application,orthodontics,orthopedic,prosthetics,rehabilitation,properties,implant,drive,progress,prostheses"were used as English search terms.Finally,91 articles were included for review. RESULTS AND CONCLUSION:(1)Shape memory alloy has the characteristics of corrosion resistance,wear resistance,biocompatibility,fatigue resistance,kink resistance and other properties.Compared with other traditional materials(stainless steel,titanium alloy,cobalt-chromium alloy,etc.),shape memory alloy has lower elastic modulus and no biological toxicity,which is suitable for long-term implantation as an implant prosthesis.Due to its shape memory effect and excellent mechanical properties,it is mainly used as a driving element or as a bridge connecting the device and the human body in artificial limbs,orthoses and rehabilitation equipment.(2)The use of shape memory alloy drive elements can reduce the weight of the device,eliminate noise,easy to operate,easy to carry,better assist joint movement;compared with the use of pneumatic,hydraulic,and electrical drive methods of the device,it has obvious advantages.(3)In addition,shape memory alloy can produce permanent and stable stress during deformation.Compared with stainless steel,titanium alloy and aluminum alloy,shape memory alloy has a higher material recovery rate and does not need to be replaced and adjusted frequently,so it is more practical in the correction of deformity.(4)At present,shape memory alloy is most commonly used in orthosis,and the best clinical application effect is in stapes prosthesis.However,due to the limitations of technology and cost,shape memory alloys are rarely used in artificial limbs and rehabilitation equipment,and there is a lack of large sample size studies on the application effect.(5)Although shape memory alloys have been developed in the field of auxiliary and rehabilitation,there are still many problems:it is difficult to accurately control the shape memory alloys;the cooling speed of shape memory alloy is slow;the deformation speed of shape memory alloy cannot be controlled;there is a lack of comparative research and expert consensus on shape memory alloys with different properties;shape memory alloys are costly and expensive.(6)In the future,attention should be paid to the development of new shape memory alloys,increase comparative research,and use new technologies and methods(such as 4D printing)to solve the existing problems,so as to develop high-performance assistive devices and rehabilitation equipment.

Objective:To compare the predictive performance of different machine learning models using pre-hospital data to predict adverse inhospital outcome in patients with severe trauma.Methods:A retrospective cohort study was conducted to analyze the clinical data of 100 135 patients with severe trauma from the National Trauma Data Bank (NTDB) from January 2017 to December 2018. There were 69 644 males and 30 480 females apart from 11 patients with missing gender information, with the range age of 16-89 years [(50.1±21.1)years]. Clinical characteristics included demographic information (sex and age), trauma type (blunt or penetrating trauma), pre-hospital time [emergency medical services (EMS) response time, EMS scene time, and EMS transport time], pre-hospital vital signs (systolic blood pressure, pulse rate, respiratory rate, and oxygen saturation), trauma score [Glasgow coma score (GCS) and injury severity score (ISS)]. The original data were divided into the training set (in the year 2017) and the testing set (in the year 2018) according to the year of admission, including 50 429 patients in the training set and 49 706 patients in the testing set. The patients were classified into non-adverse outcome group ( n=94 526) and adverse outcome group ( n=5 609), according to whether they had an adverse outcome or not. There were 2 808 patients with adverse outcome in the training set and 2 801 patients with adverse outcome in the testing set. All models were built based on the training set. Eight machine learning algorithms consisting of neural network (NNET), naive Bayes (NB), gradient boosting machine (GBM), adaptive boosting (Ada), random forest (RF), bagging tree (BT), categorical boosting (CatBoost) and extreme gradient boosting (XGB) were used to construct prediction models for clinical outcomes among patients with severe trauma based on their clinical features. Models were evaluated according to the sensitivity, specificity, area under the receiver operating characteristic (ROC) curve (AUC) and Hosmer-Lemeshow goodness-of-fit test. Results:Of the NNET, NB, GBM, Ada, RF, BT, CatBoost and XGB models in the testing set, the sensitivity was 0.84, 0.83, 0.27, 0.79, 0.83, 0.81, 0.62 and 0.78, respectively; the specificity was 0.79, 0.76, 0.81, 0.79, 0.79, 0.74, 0.83 and 0.79, respectively; the AUC was 0.89 (95% CI 0.88, 0.90), 0.86 (95% CI 0.85, 0.87), 0.54 (95% CI 0.53, 0.55), 0.86 (95% CI 0.85, 0.87), 0.88 (95% CI 0.88, 0.90), 0.83 (95% CI 0.82, 0.85), 0.77 (95% CI 0.76, 0.79) and 0.86 (95% CI 0.85, 0.87), respectively. The NNET model had the best differentiation. In terms of calibration degree, both NNET and NB showed good performance ( P>0.05 for Hosmer-Lemeshow goodness-of-fit test). Conclusion:The NNET model has a favorable predictive performance for adverse inhospital outcome in patients with severe trauma, which may provide a reference for the rapid prediction of prognosis in patients with severe trauma.

Pulmonary blast injury has become the main type of trauma in modern warfare, characterized by externally mild injuries but internally severe injuries, rapid disease progression, and a high rate of early death. The injury is complicated in clinical practice, often with multiple and compound injuries. Currently, there is a lack of effective protective materials, accurate injury detection instrument and portable monitoring and transportation equipment, standardized clinical treatment guidelines in various medical centers, and evidence-based guidelines at home and abroad, resulting in a high mortality in clinlcal practice. Therefore, the Trauma Branch of Chinese Medical Association and the Editorial Committee of Chinese Journal of Trauma organized military and civilian experts in related fields such as thoracic surgery and traumatic surgery to jointly develop the Clinical treatment guideline for pulmonary blast injury ( version 2023) by combining evidence for effectiveness and clinical first-line treatment experience. This guideline provided 16 recommended opinions surrounding definition, characteristics, pre-hospital diagnosis and treatment, and in-hospital treatment of pulmonary blast injury, hoping to provide a basis for the clinical treatment in hospitals at different levels.

Cannulated Screw is a common internal fixation for the treatment of femoral neck fractures. However, the traditional implantation method has disadvantages such as inaccuracy and large radiation exposure. Based on the anatomical characteristics of the femoral neck and geometric principles, we develop a novel guide device for cannulated screws insertion. The cadaver experiment showed that it can improve the accuracy of cannulated screws implantation, reduce puncture attempts and the radiation exposure of doctors and patients.
Bone Screws ; Femoral Neck Fractures/surgery* ; Fracture Fixation, Internal ; Humans ; Robotic Surgical Procedures

Blast injury of the chest injury is the most common wound in modern war trauma and terrorist attacks, and is also the most fatal type of whole body explosion injury. Most patients with severe blast injury of the chest die in the early stage before hospitalization or during transportation, so first aid is critically important. At present, there exist widespread problems such as non-standard treatment and large difference in curative effect, while there lacks clinical treatment standards for blast injury of the chest. According to the principles of scientificity, practicality and advancement, the Trauma Society of Chinese Medical Association has formulated the guidance of classification, pre-hospital first aid, in-hospital treatment and major injury management strategies for blast injury of the chest, aiming to provide reference for clinical diagnosis and treatment.

Objective To investigate functional role and clinical significance of the methylation in the promoter of TPAP gene in the development and progression of pancreatic cancer.Methods Surgically resected specimen from 68 patients who were pathologically diagnosed as pancreatic cancer in Changhai Hospital from July 2006 to August 2009 were collected.The methylation in the promoter of TPAP gene in tumor and nontumor adjacent tissue was detected by methylation specific PCR.Results The methylation rate of tumor and non-tumor adjacent tissue was (0.214 ± 0.057) ％ and (0.084 ± 0.096) ％,respectively,and pancreatic cancer tissue had significantly higher methylation rate than the adjacent tissue.Hypermethylation of TPAP gene was not correlated with age,gender,tumor differentiation,lymphatic metastasis,serum CEA and CA19-9,but was positively correlated with distant metastasis.Conclusions Hypermethylation in the promoter of TPAP gene may participate in the invasion and metastasis of pancreatic cancer and the hypermethylation of the promoter is closely associated with the tumorigenesis and development of pancreatic cancer.

Objective To explore the effect of persistent stress on the ultrastructure of cancellous bone in the process of fracture healing.Method A transverse osteotomy on both sides of the femoral tuberositas was performed in 20 adult dogs. One side was fixed with a self-designed tuberositas memofy-pressure connector (TMC) which was made of NiTi shape memory alloy, and the other with compressive steel-wire (SW) cerclage.Five animals in each group were sacrificed at 2, 4, 8, 12 weeks after operation and observed under transmission electron microscope.Results The fracture healing was accelerated in the TMC group.The osteoblasts, chondroblasts and collagen fibers at the fracture sites showed significantly different morphology between the 2 groups at every observation time.Most cells and collagen fibers in the TMC group grew along the same direction as the stress, but those in the SW group grew in disorder.Both the number and functional activity of the osteoblasts and chondroblasts were higher in the TMC group than in the SW group.Conclusion Persistent stress can enhance healing and bone reconstruction following a cancellous bone fracture.

Objective To design a new method of posterior wall reconstruction for severely corn-minuted and obsolete fracture of the posterior wall of the aeetabulum. Methods (1) Biomechanical study (from two perspectives: the stability and the stress distribution on the femoral head and the acetabu-lure) : six fresh adult' s pelvis and femur specimens were collected and divided into experimental group ( consisted of the left sides) and control group ( consisted of the right sides). After the defects of the pos-terior wall were made, the defects were anatomically reconstructed with the harvested ilium by acetabular tridimentional memory fixation system (ATMFS) in the experimental group, whereas the acetabular frag-ments were repositioned to the defect sites and fixated by the plates and screws in the control group. Lon-gitudinal and latitudinal displacement, stability of the anatomically reconstructed posterior wall of the ace-tabulum, the fitness of femoral head to the acetabulum after anatomical reconstruction and mean and maxi-mum pressure of anterior wall, posterior and cupuh of the acetabuhm were analysed and compared. (2) Cinical study: The posterior wall defect on the harvested ilium piece was repaired with 3-directional loc-king of ATMFS in 10 male patients (at age of 16-50 years, mean 36.4 years) from January 2000 to June 2002. There were seven patients with flesh acetabular fractures and three with old acetabular fractures.The period from fracture to reconstruction for the patients with old fractures was 58-251 days ( 137.7 days an average). The patients were foUowed up for 5.8 years (average 5.2-7.1 years). Results (1) Biomechanical study showed no statistical difference upon stability and fitness of femoral head to acetabu-lum after reconstruction in experimental and control groups. (2) Clinical study: postoperative X-ray film showed no repeated displacement of the fracture and the patients began out-of-bed movement with weight bearing after 1.6 months (1.2-2.1 months). Heterotopic ossification was found in two patients, with no influence on the joint function. According to the elinieal ranking standard of Modified d' Aubigne and Postal, the excellence rate was 93%. Conclusions Anatomical reconstruction of posterior wall of the acetabulum by using serf ilium with ATMS has good stability and stress distribution of the femoral head and the reconstructed acetabulum in clinical application and offers a new method for treatment of severely comminuted and obsolete fracture of posterior wall of acetabulum.

OBJECTIVE: To compare the clinical effect between Gamma nail and proximal femoral nail (PFN) on the treatment for femoral intertrochanteric fractures in the elderly.METHODS: A total of 131 cases (39 males and 92 females; aged 70?81 years, mean age of 76 years) with femoral intertrochanteric fractures were collected from the Department of Orthopaedics, the Affiliated Changhai Hospital of the Second Military Medical University of Chinese PLA from January 2005 to January 2008. Femoral intertrochanteric fractures were classified based on AO system, including type A1 (n=56) and type A2 (n=75). All cases were randomly divided into Gamma nail group (n=65) and PFN group (n=66). Pre- and post-operative blood loss, blood transfusion volume, operating time, and length of stay were recorded, while the complications were detected following nail implantation. Functional changes of injured limbs were detected after 9 months.RESULTS: At 9 months after following up, there was no significant difference in blood loss, blood transfusion volume, operating time, and length of stay between the two groups before and after implantation (P> 0.05). Furthermore, complications did not occur during or after implantation. Six cases in the PFN group had infection in which of them had diabetes mellitus. There were no complications such as cutting out of femoral head, femoral shaft fractures, breakage of internal device or pushing out phenomenon. All cases got bone union at the final follow-up of nine months and did not get nonunion, delayed union of fractures or shortening of injured extremity.CONCLUSION: Gamma nail and PFN have equal effect on the treatment of femoral intertrochanteric fractures in the elderly.

BACKGROUND:Swan-like memory connector (SMC) can form a three-dimensional fixation on long bone shaft,ensure the stability of fracture ends,and produce a continuous dynamic compressive stress on the fracture ends.Insulin-like growth factorⅠ (IGF-Ⅰ) regulates bone development and metabolism,cell differentiation,as well as mitosis.During the union process of fracture,IGF-I is effective to promote cellular proliferation,stimulate bone formation and result in chondrogenesis.OBJECTIVE:To quantitatively determine the effect of SMC and conventional dynamic compression plate (DCP) on the concentration of local IGF-Ⅰ in the union duration of rabbit humerus fracture.DESIGN,TIME AND SETTING:A controlled observational animal study was performed in the laboratory,Department of Orthopaedics,Changhai Hospital,the Second Military Medical University of Chinese PLA from January to May in 2007.MATERIALS:SMC was Ni-Ti alloy panel,comprising 50%-53% Ni,was customized by Lanzhou Seemine Shape Memory Alloy Co.,Ltd.The temperature of shape recovery was (33±2) ℃.METHODS:Thirty adult New Zealand rabbits were used in this study and were processed into osteotomy.The experiment sides of rabbit humerus were cut and fixed with SMC at random,serving as SMC group,and the other sides were cut at the same position and fixed with DCP,serving as DCP group.Each five animals were put to death at the time points of 2,3,4,6,8,and 12 weeks after internal fixation.Specimens were obtained from the areas that were 0.5 cm besides the fracture line.MAIN OUTCOME MEASURES:Following internal fixation,the contents of local IGF-Ⅰ in the specimens of different time points (2,3,4,6,8,and 12 weeks) were determined in both SMC group and DCP group.RESULTS:In the SMC-treated group,the contents of IGF-I increased 2 weeks after internal fixation,reached the maximum at 6 weeks,and then decreased at 8-12 weeks.In the DCP-treated group,the contents of IGF-Ⅰincreased 2 weeks after internal fixation,reached the maximum at 8 weeks,and then decreased at 12 weeks.No significant differences were found between the SMC group and the DCP group at 2,8,12 weeks after internal fixation (P ＞ 0.05).Compared with the DCP group,the SMC group had a remarkably higher content of IGF-Ⅰ at the time points of 3,4 and 6 weeks (P ＜ 0.05).The difference was the most statistically significant at 4 weeks.CONCLUSION:Compared with conventional DCP,the SMC could better promote the secretion of IGF-Ⅰin fracture and facilitate the fracture union due to the continuous dynamic compressive stress and three-dimensional fixation.