Objective To introduce a new technique for treatment acetabular fractures with nitinol tridimensional internal fixation system. Methods According to the characteristics of nitinol and acetabular anatomy, a new internal fixation system for acetabular fracture, acetabular tridimensional memoryalloy-fixation system (ATMFS), was designed. This system consisted of anterior column, posterior column, arch teeth and trochanter device. During operation, these devices were transformed in iced water first, after fracture reduction they were inserted into bones, finally, these devices were reverted to their original shape by warm saline. Till October 2001, 41 cases acetabular fractures were treated with this system. All these cases were followed from 6 to 28 months. Results This system could transform the complicated and comminuted fracture to its anatomic position, and was easy to use in operation. Bone healing time averaged 1.6 months in 38 cases, and the hip function recovered time averaged 2.5 months. Heterotopic ossification which led to joint functional disturbance in one case, and myositis ossificans which caused joint dysfunction in two cases. One case was complicated by infection which was cured and good function was reserved. Conclusion ATMFS provides a new and efficacious method for the anatomic reduction or reconstruction of comminuted acetabular fractures.

Objective To develop a new method of treating fractures and nonunion of radial and ulnar diaphyses. Methods We designed a kind of radius-ulna shape memory connector (RSMC) on the basis of the shape memory property of nitinol alloy and the anatomic characteristics of radial and ulnar diaphyses. It is capable of providing 3-D fixation and exerting continually longitudinal compression upon fracture sites. It was used in 31 cases (57 bones) of fresh fractures and 39 cases (53 bones) of nonunion, totaling 70 cases (110 bones). Results The mean follow-up time was 1.5 years(from 7 months to 2 years). In the fresh fracture group, no delayed union or nonunion was observed, and the solid bone healing time averaged 2.3 months. In the nonunion group, all the cases were cured at one time and the solid bone healing time averaged 3.5 months, but two cases were complicated with slight skin infection which had little influence on the internal fixation and bone healing. Conclusion RSMC can provide a new and efficacious method for the treatment of fracture and nonunion of radial and ulnar diaphyses.

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 analyze the design of Nitinol Patellar Concentrator (NT-PC) and its biomechanic characteristics for treating comminuted patellar fractures.Methods:NT-PC and patellar was analyzed by ANSYS software,the finite element was three dimension brick unit with 20 nodes, 8 faces, and the degree of freedom was 6.In NT-PC,10 483 units were divided and the number of nodes was 17 959;In Patellar,8 775 units were divided and the number of nodes was 15 847.The patellar model was loaded according to the 5 converging directions of NT-PC.Results:NT-PC had tension force on its internal face and pressure force in its external face.The maximum value was 195.8 MPa and -18 MPa,which was far from its utmost stress and fatigue limit.The memory converging force of NT-PC was 134 N.The stress (0.8 MPa) was evenly distributed on the patellar surface.Stress calculation of every node indicated that positive stress was the main stress.Conclusion: The design of NT-PC is reasonable and has good reusing character.After fixation, exercise is allowed immediately after operation.The continual positive stress is good for the stability of fracture end and fracture healing.

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.

Objective To research on the new technique and method of bone grafting for nonunion of four limbs. Methods A new method of bone grafting was developed to take advantage of Nitinol Shape Memory Connector. It included splinting mode, padding mode and seeding mode. 148 cases of bone nonunion in 134 patients were treated with the modified method. Results The patients were followed up for 5.5 months to 6 years, with an average period of 2.25 years. On the average, the nonunion healed with lamellar bone 3.5 months after the operation. The healing rate was 99.3% . Conclusion The author s modified bone grafting provides a new and efficacious method for treatment of the limb nonunion.

Objectives To analyze the risk factors for transfusion in very low birth weight infants and to explore the strategies for prevention of anemia. Methods Neonates with gestational age <37 weeks and birth weight <1500 g admitted from January 2015 to June 2016 were included. The neonates were divided into blood transfusion group and non-blood transfusion group. The general conditions and complications were compared, and the risk factors of blood transfusion and the related factors were analyzed. Results One hundred fifty cases of very low birth weight infants were included, among whom 108 cases were from blood transfusion group and 42 cases were from non-blood transfusion group. Compared with the non-blood transfusion group, the gestational age and body weight of the blood transfusion group were smaller, the basic hemoglobin was lower, the parenteral nutrition time was longer, and the total volume of blood collection in hospital was higher, and these differences were all statistically significant (P all<0.05). The incidence of bronchopulmonary dysplasia (BPD), acute respiratory distress syndrome (RDS) and patent ductus arteriosus (PDA) in the blood transfusion group were higher than those in the non-blood transfusion group, and they were all statistically different (P all <0.05). Multiple linear regression analysis showed that the volume of blood transfusion was higher when the gestational age and body weight were smaller, the longer parenteral nutrition was needed, and the total volume of blood taken from the hospital was higher (P all <0.05). Conclusions The gestational age, body weight, parenteral nutrition time and the total volume of blood collection in very low birth weight infants have different effects on blood transfusion risk and transfusion volume. The incidences of BPD, RDS, and PDA in infants with blood transfusion are higher.

Objective:To study the biomechanical basis of swan like memory compressive connector (SMC) for treating fractures and nonunions of humerus. Methods:The study was performed by electrometric, two and three dimensional (3D) photoelasticity techniques. By gauging and multiple time standardization, load strain curve was got, then the dynamic memory force of SMC was calculated. The dynamically compressive force of swan neck compressive part was calculated by 2D photoelasticity. By precision moulding, the epoxy resin 3D photoelasticity humeral model was established, then it was fixated by SMC, meanwhile, an epoxy resin cirque was used to share the continuously memorial compress. The 3D stress distribution of humeral model was got, and 6 space component stress of the inspected node was divided by Leize polarizing microscope. Results:The continuously memory force of SMC was 110.35 N. The longitudinal dynamical compressive memory force was 163.88 N. 3D photoelasticity method showed that the swan neck compressive part of SMC, swan body connecting part of SMC and swan wing holding part of SMC were in consistent with each other, memorably holding bone, 3D fixation style was formed, and overall stress distribution was produced.. Conclusion:The stress field produced by 3D memory fixation of SMC is good for the treatment of fractures and nonunions. Early function exercises are allowed, and the fracture healing is prompted.

Objective:To study the biomechanical basis of swan like memory compressive connector (SMC) for treating fractures and nonunions, and the facilitating effects of dynamic memorial stress of SMC for bone healing. Methods:By computer emulation and three dimensional (3D) finite element analysis, the biomechanical behavior of humeral type connector for fixing humerus was emulated and analyzed. The finite element model of humeral type connector was divided into 3 487 units. The number of nodes was 5 397. The element was a unit with 20 nodes, 4 faces. The finite element model of humerus was divided into 5 783 units, the number of nodes was 9 863. And the finite element was a 3D unit with 10 nodes, 4 faces.Results:When the connector fixated humerus, it came in for tension stress in its inner surface, and compressing stress in its outer surface. The maximum first structural major stress of metamorphosed compressive part was 224.5 MPa and -34 MPa, far less than its utmost stress and fatigue limit. The initiative memorial bone holding force for maintaining axial stability was 125.05 N, and the longitudinal initiative memorial compression force was 196 N. The stress distribution in fixed humerus was even, the stress in most nodes was positive stress. Conclusion:The SMC has good anti fatigue and reuse characters. The dynamic memorial compressive stress field is good for the stability of fixation and enhancement of bone healing.