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Objective: To explore establishment and finite element analysis of personalized proximal clavicular anatomical plate screw fixation model., Methods: A 40-year-old male healthy volunteer was selected and the finite element analysis modules of 3D reconstruction software Mimics 15.01, Hypermesh 2019 and Abaqus 2020 were used. The finite element model of anatomic plate at the proximal clavicle was established, and a vertical load of 250 N was applied to the distal end of long axis of clavicle about 15 mm, then the overall structure, plate and screw displacement cloud image, Mises stress distribution were observed., Results: The displacement distribution of the overall structure shows the maximum displacement was distributed on the distal clavicle. Under the four conditions of normal upper limb weight, longitudinal clavicle fracture, oblique fracture and shoulder impact violence during fall, longitudinal clavicle fracture and oblique fracture, the maximum displacement were 1.04 mm, 1.03 mm, 1.35 mm and 1.33 mm, respectively. The displacement cloud map of titanium alloy steel plate showed the largest displacement was distributed near the distal clavicular bone, and the maximum displacement were 0.89 mm, 0.88 mm, 1.10 mm and 1.09 mm, respectively. The displacement cloud map of titanium alloy screw showed the largest displacement was distributed at the root of the distal screw, and the maximum displacement were 0.88 mm, 0.87 mm, 1.08 mm and 1.06 mm, respectively. Mises stress distribution showed the maximum stress was mainly distributed on titanium alloy plates and screws, and the stress on the clavicle was very small. Mises stress distribution cloud showed the maximum Mises stress was distributed at the second row of screw holes near the clavicle, and the maximum Mises stress were 673.1, 678.1, 648.5, 654.4 MPa, respectively. The maximum stresses of titanium alloy screws were 414.5, 417.4, 415.8 and 419.7 MPa, respectively., Conclusion: The biomechanical changes of personalized proximal clavicular anatomical plates are demonstrated by using 3D finite element method to provide biomechanical data for personalized proximal clavicular anatomical plates.

Objective: To explore feasibility of 3D metal printing technology combined with virtual design proximal clavicle anatomical plate., Methods: A 52-year-old male healthy volunteer was retrospectively selected to design proximal clavicle anatomical plate system by using Mimics15.01,NX12.0 and other software. STL data were input into 3D printer to print 1:1 clavicle model and proximal clavicle anatomical plate. The fit of the plate was tested in vitro and the accuracy of screw position was evaluated by imaging. Printing time of model,nail path design and fabrication time of the anatomical plate at proximal clavicle were recorded., Results: The 3D metal printing proximal clavicle anatomical plate fitted well to clavicle model,orientation of proximal clavicle locking screw was accurate,and X-ray and CT scan showed the screw position was good. Printing time of model,the time of nail path design,and the time of making anatomical plate of proximal clavicle were 120,15 and 300 min respectively., Conclusion: The proximal clavicular anatomical plate system based on 3D metal printing technology could achieve good lamination of proximal clavicular fracture plate and precise screw placement,providing a new and accurate surgical method for the treatment of the proximal clavicular fracture.

Objective: To summarize the surgical treatment of different proximal clavicle fractures, and discuss the classification of proximal clavicle fractures., Methods: Total of 24 patients with displaced proximal clavicle fractures were treated from January 2017 to December 2020 including 16 males and 8 females, aged 28 to 66 years old. Among them, 20 cases were fresh fractures and 4 cases were old fractures. According to the Edinburgh classification, 14 cases were type 1B1 fractures and 10 cases were type 1B2 fractures. The different internal fixation methods were selected for internal fixation treatment according to different fracture types.The operation time, blood loss, preoperative and postoperative displacement difference, fracture healing time and Rockwood scoring system were recorded., Results: All patients were followed up for 12 to 24 months. There were no patients with infection or loss of reduction after the operation. Three patients had internal fixation failure after operation, and the internal fixation device was removed. Results The operation time was 30 to 65 min, and the blood loss was 15 to 40 ml. No important nerves, blood vessels, or organs were damaged. The imaging healing time was 3 to 6 months. According to the Rockwood functional score, the total score was (13.50±1.86), pain (2.57±0.50), range of motion (2.78±0.41), muscle strength (2.93±0.28), restricted daily activity (2.85±0.35), subjective results (2.63±0.61);the results were excellent in 20 cases, good in 3 cases, fair in 1 case., Conclusion: Proximal clavicular fracture is a type of fracture with low incidence. According to different fracture types, different internal fixation methods and treatment methods can be selected, and satisfactory surgical results can be achieved.

Objective: With the help of finite element analysis, to explore the effect of proximal humeral bone cement enhanced screw plate fixation on the stability of internal fixation of osteoporotic proximal humeral fracture., Methods: The digital model of unstable proximal humeral fracture with metaphyseal bone defect was made, and the finite element models of proximal humeral fracture bone cement enhanced screw plate fixation and common screw plate fixation were established respectively. The stress of cancellous bone around the screw, the overall stiffness, the maximum stress of the plate and the maximum stress of the screw were analyzed., Results: The maximum stresses of cancellous bone around 6 screws at the head of proximal humeral with bone cement enhanced screw plate fixation were 1.07 MPa for No.1 nail, 0.43 MPa for No.2 nail, 1.16 MPa for No.3 nail, 0.34 MPa for No.4 nail, 1.99 MPa for No.5 nail and 1.57 MPa for No.6 nail. These with common screw plate fixation were:2.68 MPa for No.1 nail, 0.67 MPa for No.2 nail, 4.37 MPa for No.3 nail, 0.75 MPa for No.4 nail, 3.30 MPa for No.5 nail and 2.47 MPa for No.6 nail. Overall stiffness of the two models is 448 N/mm for bone cement structure and 434 N/mm for common structure. The maximum stress of plate appears in the joint hole:701MPa for bone cement structure and 42 0MPa for common structure. The maximum stress of screws appeared at the tail end of No.4 nail:284 MPa for bone cement structure and 240.8 MPa for common structure., Conclusion: Through finite element analysis, it is proved that the proximal humerus bone cement enhanced screw plate fixation of osteoporotic proximal humeral fracture can effectively reduce the stress of cancellous bone around the screw and enhance the initial stability after fracture operation, thus preventing from penetrating out and humeral head collapsing.

Objective: To investigate the CT measurement of sacral anatomical parameters and understand the safe nail placement channel of DenisⅠ area with a new sacral butterfly plate., Methods: The CT data of 101 normal adult sacrum from January 2020 to June 2020 were retrospectively analyzed, including 49 females and 52 males, aged(49.11±15.02) years old. Firstly, the three-dimensional model of sacrum was reconstruct, the three-dimensional model according to the plane was re segment to be measured, and data measurement and statistical analysis were carried out., Results: The vertical distance from the lower edge of superior sacral articular process to the lower edge of S 2 posterior sacral foramen was (42.55±4.73) mm;The horizontal distance from the lateral sacral crest of S 1 , S 2 and S 3 hole plane to the sacroiliac joint surface was (19.09±3.07) mm, (15.34±2.69) mm and (8.29±2.48) mm respectively;The plane of S1 hole moves forward from the lateral sacral ridge, the inner and outer angles are (7.49±7.49)° and (24.07±4.89)° respectively;The inside and outside angles of S 2 hole plane are (-3.10±8.95)° and (24.95±5.74)° respectively. There were significant differences between different genders except S 1 horizontal distance and S 1 medial angle, and there was no correlation between age and all data., Conclusion: The new sacral butterfly plate has enough safe nail placement range in DenisⅠ area;There are differences in sacral morphology among adults. The differences are mainly related to gender but not age.

Objective: To investigate the feasibility of a drill template for the placement of guided template of middle and upper thoracic percutaneous vertebroplasty in thoracic pedicle approach on digital design and 3D printing technology., Methods: The preoperative CT images of 20 patients with thoracic fracture were collected retrospectively. With the 3D soft tissue printing technology, the data was reconstructed by 3D imaging reconstruction software to produce 1∶1 three dimensional soft tissue model. The pedicle screw channel and the digital template were designed by the 3-matic module of Mimics15.0 software. After guide template was printed by 3D printer and three dimensional template was fixed on the model, 2.0 mm Kirschner was placed and the accuracy of a drill template was observed by CT scans, bone cement was injected through the puncture tube and verified with images. The time of nail guide design, guide template production and cost were recorded., Results: The effectiveness of three dimensional thoracic model and digital guided template of middle and upper thoracic percutaneous vertebroplasty of thoracic fractures in thoracic pedicle approach was confirmed. Kirschner was placed and the accuracy of screw placement was confirmed with CT scanning. Template and the corresponding anatomical landmark fitted well, bone cement had showed good filling. The average printing time of upper thoracic spine model with soft tissue, the mean time of nail guide design, guide template production and cost were (719.00±3.03) min, (12.30±1.01) min, (55.50±10.30) min and RMB 3 150 yuan on average respectively., Conclusion: By means of individual design and 3D soft tissue printingtechnology, accurate placement of guided template of middle and upper thoracic percutaneous vertebroplasty could be realized.

Objective: To compare the effect of percutaneous bridging plate and retrograde suprapubic intramedullary screw in the treatment of anterior ring fracture of pelvis., Methods: From January 2013 to June 2017, 40 patients with unstable pelvic fractures involving anterior ring were analyzed retrospectively. According to the fixation method, they were divided into two groups, there were 20 patients in percutaneous bridging plate group (plate group) including 9 males and 11 females; according to tile classification, fractures were classified as type B1 in 1 case, type B2 in 14, type B3 in 2, type C1 in 2 and type C2 in 1. There were 20 cases in retrograde suprapubic intramedullary screw group (screw group) including 10 males and 10 females; according to tile classification, there were 1 case of type B1, 12 cases of type B2, 3 cases of type B3, 3 cases of type C1 and 1 case of type C2. The incision length, operation time, times of fluoroscopy, intraoperative bleeding volume, postoperative Matta score, postoperative complications and the last follow-up Majeed function score of the two groups were compared and analyzed., Results: Both groups were followed up for 8 to 15 (12.25±2.24) months in the plate group and 6 to 18 (12.4±2.6) months in the screw group, there was no significant difference between the two groups. The incision length of screw group was (3.85±0.75) cm shorter than that of steel plate group (7.05±1.39) cm; the operation time of screw group was (27.70±5.36) min longer than that of steel plate group (15.10±2.07) min; the fluoroscopy times of screw group was (6.00±1.83) more than that of steel plate group (3.75±1.33) . The bleeding volume was (22.50±10.82) ml in of screw group, (25.00±9.93) ml in steel plate group, there was no significant difference between the two groups ( P >0.05) . There was no significant difference in Matta evaluation and Majeed functional score in the last follow-up. One case of superficial skin infection occurred in screw group, one case of superficial skin infection and one case of transient paralysis of lateral femoral cutaneous nerve occurred in steel plate group., Conclusion: Percutaneous bridging plate and retrograde suprapubic intramedullary screw fixation of pelvic anterior ring fracture have the same effect. The operation time of the percutaneous plate group was shorter, the times of intraoperative fluoroscopy was less, and the learning curve was shorter, but the variation of the lateral femoral cutaneous nerve should be noted during the operation.

Objective: To investigate the surgical treatment and outcome of capitellum and trochlea fractures in adult through Kaplan approach associated with anteromedial approach., Methods: From September 2012 to September 2016, 15 patients with capitellum and trochlea fractures were treated by Kaplan approach associated with anteromedial approach. Of the 15 cases, there were 6 males and 9 females, aged from 21 to 69 years old, with a mean of (42.0±10.5) years old. Eight patients had fractures on the left and 7 patients on the right. All the fractures were classified into type IIA(5 cases), type IIIA(4 cases) and type IIIB (6 cases) according to Dubberley classification. The results were evaluated by Mayo elbow function score for analysis., Results: All the patients were followed up, the mean follow-up duration was(13.0±4.7) months(ranged 8 to 26 months). The mean Mayo elbow function score was 85.6±5.3(ranged 76 to 94). Postoperative follow-up had 4 cases excellent, 7 cases good, and 4 cases fair. Average arc of motion in elbow was(129.2±12.1)° in flexion and(6.6±1.9)° in extension., Conclusions: The surgical treatment of capitellum and trochlea fractures in adult through Kaplan approach associated with anteromedial approach can better expose the fractures to achieve the satisfactory exposure and finish the surgical procedure, and the short-term outcome is satisfactory., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© 2018 by the China Journal of Orthopaedics and Traumatology Press.)

Objective: To compare the stability of subaxial cervical anterior transpedicular screw(ATPS) fixation and three traditional fixations for three-column injury., Methods: Six specimens of cervical spine were prepared. After measurememt of the range of motion(ROM) in intact state, the specimens were made into three-column injury models. The models were reconstructed with an anterior cervical cage, and stabilized by ATPS, anterior plate(AP), anterior plate + lateral mass screw(AP+LMS) and posterior transpedicular screw(PTPS). The ROM of the models in the four states were measured, and the results of data were compared after standardization., Results: The normalized ROM of ATPS state in flexion-extension, lateral bending, axial rotation were(77.17±4.75)%, (82.00±2.61)%, (83.17±2.23)%, which were significant small than those in intact state( P <0.05). The normalized ROM of AP state in flexion-extension, lateral bending, axial rotation were(119.67±7.42)%, (116.33±7.53)%, (112.67±5.99)% , which were significant larger than those in intact state( P <0.05). The normalized ROM of AP in all directions were significant larger than those of ATPS( P <0.05). There was no significant difference between normalized ROM of PTPS state and those of ATPS state in flexion-extension and lateral bending( P >0.05). The normalized ROM of PTPS state in axial rotation was(6.83±2.48)% and was significant larger than that of ATPS state( P =0.009). The normalized ROM of AP+LMS state in flexion-extension was(68.50±2.43)%, which was significant smaller than that of ATPS state( P =0.003). There was no significant difference between the normalized ROM of AP+LMS state and those of ATPS state in lateral bending and axial rotation( P >0.05)., Conclusions: Subaxial cervical three-column injury model reconstruction by ATPS can provide the adequate primary stability, of which biomechanics property is superior compared to AP and PTPS, and is similar to that of AP+LMS. It can be applied to the patients with no need to decompression and reduction through posterior approach., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© 2018 by the China Journal of Orthopaedics and Traumatology Press.)

Objective: To evaluate the efficacy and advantages of personalized 3D printing-guided template of lateral superior ramous of pubic intramedullary lag screw., Methods: From July 2015 to December 2016, 20 patients with the superior and inferior ramous of pubis fracture were treated with lag screws placement. All the patients were divided into test group(with guided template) and control group(with general operation). There were 7 males and 3 females with an average age of (46.20±3.03) years old in test group and 6 males and 4 males with (48.50±2.25) years old in control group. There were 6 cases and 5 cases of superior and inferior branches fractures of pubic on the left side and 4 cases and 5 cases on the right side in two groups respectively. The operation time, perspective times and bleeding loss were compared between two groups., Results: The test group and the control group had no statistically significant relative to gender, age, fracture classification. The average time of surgery, average intraoperative fluoroscopy times, mean blood loss in test group were (31.0±5.3) min, (3.5±2.1) times, (75.6±10.5) ml respectively, and in control group were(55.0±6.8) min, (27.6±3.2) times, (85.5±12.5) ml respectively. There were significant Statistical differences between two groups( P <0.05) in average operation time and average fluoroscopy times, however, mean blood loss had no significant differences between two groups( P >0.05)., Conclusions: The personalized guide template based on 3D printing technology could realize precise placement of the lateral intramedullary lag screw fixation in the superior branch of pubic, also could save the operation time and reduce the times of radiation exposure of patients and surgeons., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose.

Objective: To investigate the feasibility of a drill template for the placement of reverse intramedullary lag screws on the outside of the pubis based on digital design and 3D printing technology., Methods: The preoperative CT images of a 23-year-old male patient with pelvic fracture were collected retrospectively. According to the Young and Burgess classification, the type of pelvic fracture was LC IIwith the 3D printing technology. The data was reconstructed by 3D imaging reconstruction software to produce 1:1 three dimensional model. The screw channel and the individual drill template was designed by the softwares of Mimics 10.01 and Geomagic 12, the accuracy of a drill template was observed by X-rays and CT scans after the placement of 2.0 mm K-wires in the three dimensional template fixed on the model., Results: Three dimensional pelvic model and digital, individual drill template could meet the requirement of the placement of reverse interamodullary lay screw for the treatment of superior ramus of pubis fracture. K-wire was placed and the accuracy of screw placement was confirmed using the X-ray and CT scanning. Template and the corresponding anatomical landmark fitted well., Conclusions: With the assistance of the individual design and 3D printing technology, the accurate placement of superior ramus of pubis fracture screws can be realized. This technology is helpful to reduce the operation time and X-ray exposure of the patients and doctors., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose.