Inducing animal viruses to adapt to chicken embryos or chicken embryo fibroblasts(CEF)is a common method to develop attenuated live vaccines with full security.Canine distemper virus(CDV)also does this,but the mechanisms and particular receptors remain unclear.Virus overlay protein blot assays were carried out on CEF membrane proteins,which were extracted respectively with a Mem-PERTM kit,a radioimmunoprecipitation assay buffer or a modified co-immunoprecipitation method,and revealed a common 57 kDa positive band that differed from the 42-kDa positive band in Vero cells and also from those receptors reported in lymphocytes and293 cells,indicating a receptor diversity of CDV and the possibility of the 57-kDa protein acting as a receptor that is involved in adaptive infection of CDV Kunming strain to CEF.

[Objective]To evaluate curative effects of Osteoset~ synthetic bone transplants and internel fixations on calcaneus fracture.[Method]Twenty-three patients with calcaneus fracture,who were treated by Osteoset~ synthetic bone transplants and internel fixation,were followed up by plain X-Rays and JOA functional questionnaires.Fracture patterns were based on Sanders methods.[Result]A series of 23 patients,7 of which were sanders Ⅱ,15 were sanders Ⅲ,3 were sanders Ⅳ,were treated with ORIF and Osteoset~ implants.The preoperative Blher's angle was 4.8 degrees(standard deviation 6.6 degrees).Blher's angle increased to a mean of 26.8 degrees(SD 8.6 degrees) postoperatively.In the first 3 months after surgery,a mean decrease in the Blher's angle of 0.4 degrees(SD 2.27 degrees) occurred.One month after surgery osteoset synthetic bone transplants,which was replaced by new bone,were gradually absorbed and degraded.JOA questionnaires suggested that the whole effective rate was 92 percent.[Conclusion]Osteoset synthetic bone transplants and internel fixations has good therapeutic effects on patients with comminuted calcaneus fracture.Osteoset~ synthetic bone has the same effects as autogenous bone.

Objective To compare the clinical effectiveness between the channel-assisted mini-invasion and open Achilles shortening for treatment of the elongated Achilles tendon following previous rupture.Methods The clinical data of 19 patients admitted from Dec. 2013 to Dec. 2015 and met the inclusion criteria were analyzed retrospectively. Eight patients were treated with shortening operation by channel-assisted minimally invasive repair system, while 11 patients received dissection of Krackow Achilles tendon shortening. There was no significant difference between the two groups in gender, age, injury to operation time, preoperative calf circumference and preoperative AOFAS (American Orthopaedic Foot & Ankle Society) score (P>0.05).Results The operation time, incision length and postoperative hospital days were significantly less in min-invasion group than in incision group (P<0.05). After operation, wound healing by first intention was obtained in incision group except 1 case which got infection and healed by treatment 2 weeks later. No sural nerve and vascular injury and lower extremity deep vein thrombosis existed. MRI showed that the Achilles tendon recovered in both groups at the 8th week follow-up. The patients were followed up for 12-17 months in the mini-invasion group and 12-20 months in the incision group. The calf circumference and AOFAS score of both groups were higher in the last follow-up than that in pre-operation (P<0.05), but no significant difference existed between the two groups at the last follow-up (P>0.05).ConclusionChannel-assisted minimally invasive Achilles tendon shortening operation has not only similar effectiveness to the incision shorting operation for the treatment of elongated Achilles tendon following previous rupture, but also has the advantages of shortening operation time and stay in hospital and avoidance of sural nerve injury.

Intertrochanteric fracture is the most common hip fracture. Due to severe osteoporosis and high degree of fracture comminution, initial implant failure or nonunion occasionally occurs. It is still controversial how to formulate a more effective strategy for revision and fixation after failed primary operation for patients who have high functional needs and/or long-life expectancy. Common surgical procedures include angle-stabilized extramedullary plate systems (dynamic condylar screw or dynamic hip screw), cephalomedullary nail systems (proximal femoral nail antirotation, InterTAN, and trochanteric fixation nail advanced) with/without medial augmentation plate. For patients with intertrochanteric fracture who have suffered from primary operation failure, the basic principle for revision is to mechanically reconstruct the stable triangular structure of the proximal femur in order to improve the mechanical stability of the fracture ends as much as possible so that fracture healing and early functional exercise can be ensured. This paper reviews the clinical and biomechanical studies published, analyzes the mechanical factors responsible for failure of initial surgery, summarizes revision strategy and clinical prognosis, and provides our clinical experience and technical innovations, hoping to help clinicians in choosing an optimal revision strategy.

Objective:To develop a set of algorithms that could predict the precise size of acetabular cup preoperatively by the deep learning neural network technology.Methods:Retrospective analysis was performed on 30 patients with femoral head necrosis from April 2019 to April 2020, including 15 males and 15 females. At the age of (54.8±10.5) years (range 33-72 years). Thirteen hips on the left and seventeen hips on the right, who underwent primary unilateral THA. Based on the manually segmented hip joint CT database, a deep learning convolutional neural network was trained to realize automatic segmentation. A customized algorithm was created to fit the surface of the acetabulum. By the application of another deep learning convolutional neural network, the identification of anatomical points of the pelvis and correction of the pelvic position were realized. So that the placement of the acetabulum cup could be done. DOC (dice overlap coefficients) as well as the average error parameter were adopted to evaluate the accuracy of the above steps. The novel algorithm and Orthoview software were retrospectively used to template the acetabular cup separately. The results of both groups were compared with the actual size and the coincidence rate was calculated to evaluate the accuracy of the novel algorithm. To verify this algorithm, the conformance rate was calculated respectively.Results:Compared with other classical segmentation networks, the G-NET network can segment the pelvic with femoral head necrosis more accurately (DOC 92.51%± 6.70%). It also has better robustness. The average error of the point recognition network is 0.87 pixels. Among the 30 patients, the AI-based algorithm group had a complete coincidence rate of 96.7% and the Orthoview group had a complete coincidence rate of 73.3%. The difference was statistically significant ( χ2=6.405, P=0.011). Conclusion:The artificial intelligence-based algorithm can segment the CT image series and identify the feature points of the patient's hip accurately. Compared with the conventional 2D preoperative planning method, the AI-based algorithm is relatively more accurate. This artificial intelligence-based 3D preoperative software has promising prospect to makeaccurate surgical plan efficiently.

BACKGROUND:Transverse acetabular fracture often involves the damage of anterior and posterior columns of acetabulum. The most popular fixation of the anterior and posterior columns needs the combined anterior and posterior approach. Big trauma is not conducive to patient’s recovery after surgery. Limited incision or percutaneous minimaly invasive lag screw placement can reduce soft tissue injuries, but the strength of the fixation lacks of biomechanical verification. OBJECTIVE: To compare different types of fixations for transverse acetabular fracture, explore the appropriate fixation options that can achieve effective fixation and reduce tissue injury by combing with repair approach and the condition of soft tissue. METHODS: The fourth generation of synthetic semi-pelvic sawbones was set as a template to establish a model of acetabular transverse fracture using finite element analysis. Five different fixation options were used to fix the transverse acetabular fracture. The magnitudes of anterior and posterior displacement of transverse fracture were compared to assess the stability of different options under a simulated condition of incomplete weight bearing stand. RESULTS AND CONCLUSION:The motion at anterior column was minimal when fixed by anterior column locking plate + posterior column screw and the minimum displacement at posterior column was the fixation of anterior column screw + posterior column locking plate. Both of the motions of these two fixations were less than the reconstruction plate fixation respectively. The worst fixation was the anterior column and posterior column lag screw fixation with the largest displacement. The anterior column locking plate + posterior column screw, accomplished by single approach, could not only reduce surgical trauma, but also has a stronger stability. Moreover, this fixation option is effective method to place posterior column lag screw under direct vision and reduce the difficulty of screw implantation.

Objective To analyze indications,complications and outcomes of amputation.Methods A total of 15 patients undergone amputation in field or at tent hospital were collected for analy-zing injury severity,place where amputation was done,whether open or closed amputation and stitch re-moval time. Results There were 9 males and 6 females.at an average age of 32 years(11-51years).There were 16 amputations including Gustilo IIIB in 2 patients, Gustilo IIIC in 9 and Tscheme Ⅲin 5 according to Gustiln classification or Tscheme classification.Four patients who received amputation in field or at tent hospital developed infection and had to receive amputation again at a higher level on the limb and drainage of open wounds because of a higher infection rate due to the amputation location.Ten patients received first amputation at higher levels with open wound at station hospital but only 2 manifested infected incision.High level amputation with one stage closure was done in 1 patient who was infected and suppurated after operation and even developed bacteremia. Conclusions Infection rate following am-putation 4n field and tent clinics is rather higher,so secondary open amputations should be performed at a higher level as soon as possible.One-time and high-level open amputation plays an important role in treat-ment of severe lower limb injuries following earthquake.

Objective To discuss the causes of failure of transpedicular screw fixation in treatment of thoracolumbar fractures. Methods A retrospective analysis was done to analyze the failure causes of 24 patients (15 males and 9 females) who received pedicle screw fixation for their thoracolumbar fractures from June 2002 to June 2008 in our department. There were two patients with delayed infection, eight with pedicle screw breakage, one with connecting rod breakage, 10 with internal fixation loosening (including nut loosening) and three with poor screw position. Results All patients received reo-perations including removal of internal fixation plus debridement and lavage in two patients, simple removal of internal fixation in nine patients, removal of inter fixation and posterior fusion in two, replacement of the lengthened fixation plus posterior fusion in nine, and adjustment of the position and orientation of screw in two. All patients were followed up for 6-18 months (average 11 months) , which showed no any complications. Conclusion Improper surgical indication or approach, ineffective fusion, incorrect postoperative rehabilitation exercise, too late removal of the screws and improper surgical operation are main causes for failure of internal fixation.

Objective To investigate the cause of fracture nonunion and discuss the experience of locking plates fixation combined with autoallergic cancellous bone in the management of non-infective long bone nonunion.Methods A retrospective analysis was made in 38 patients(29 males and 9 females)with fracture nonunion treated with locking plates fixation combined with autoallergic cancellous bone from August 2006 to August 2010.Of all,22 patients were treated with plates and 16 with interlocking intramedullary nails.Results All the patients were followed up for a mean of 12 months(range,6-24 months).The bone union time for all the fractures averaged 5.3 months(range,3-7 months),with no complications like implant loosening or fracture.Conclusions Iatrogenic factor is the main cause for fracture nonunion after open reduction and internal fixation of long bone fractures and the locking plates combined with autoallergic cancellous bone are a safe and effective treatment procedure.

Objective To investigate the efficacy of external pelvic reduction frame system combined with tunnel screw fixation in the treatment of Tile C1 pelvic fracture.Methods A retrospective case series analysis of 15 patients with Tile C1 pelvic fractures from January 2014 to October 2016 was pedormed.Clinical data included seven males and eight females,aged 26-84 years (mean,48.9 years).According to Tile classification,there were five cases of type C1.1,three cases of C1.2,and seven cases of type C1.3.The average time from injury to surgery was 9.5 days (range,4-33 days).All patients received the treatment of external pelvic reduction frame system combined with tunnel screw fixation.The operation time,intraoperative blood loss,and complications were recorded.The fracture reduction quality was evaluated according to the Matta criteria,and the clinical function and neurological function were evaluated by the Majeed functional scoring system and the Gibbons sacral nerve injury grading,respectively.Results The patients were followed up for an average of 16 months (range,12-24 months).The mean operation time was 139 minutes (range,50-250 minutes),and the mean intraoperative blood loss was 90 ml (range,20-260 ml).No complications such as wound infection,loose internal fixation,rupture or loss of reduction occurred in the patients.According to the Matta score,14 patients obtained anatomical reduction,and one obtained satisfactory reduction.At the last follow-up,according to the Majeed functional scoring criteria,the results were excellent in all 15 patients,with an excellent and good rate of 100％.According to Gibbons sacral nerve injury grading,two out of the three patients with neurologic impairment before the operation recovered completely while the remaining one did not recover.Conclusion In the treatment of Tile C 1 pelvic fractures,external pelvic frame reduction system combined with tunnel screw fixation can attain satisfactory fracture reduction,reliable fixation,and good functional recovery.