Digital intelligence technologies, including artificial intelligence, big data, surgical navigation, surgical robots, and virtual reality, have been widely used in basic and clinical research in trauma and orthopedics. In order to provide trauma orthopedists with a quick overview of the current application of these technologies, this paper elaborates on the orthopedic workflow of fracture open reduction and internal fixation, on the aspects of recognition and classification of fracture X-ray images, fracture fragment segmentation based on thin-slice CT images, virtual fracture reduction, 3D fracture line heatmaps, design of an anatomical locking plate, intelligent navigation and orthopedic surgical robots, fracture reduction robots, and surgical process visualization.

OBJECTIVE: To review targeted muscle reinnervation (TMR) surgery for the construction of intelligent prosthetic human-machine interface, thus providing a new clinical intervention paradigm for the functional reconstruction of residual limbs in amputees. METHODS: Extensively consulted relevant literature domestically and abroad and systematically expounded the surgical requirements of intelligent prosthetics, TMR operation plan, target population, prognosis, as well as the development and future of TMR. RESULTS: TMR facilitates intuitive control of intelligent prostheses in amputees by reconstructing the "brain-spinal cord-peripheral nerve-skeletal muscle" neurotransmission pathway and increasing the surface electromyographic signals required for pattern recognition. TMR surgery for different purposes is suitable for different target populations. CONCLUSION TMR surgery has been certified abroad as a transformative technology for improving prosthetic manipulation, and is expected to become a new clinical paradigm for 2 million amputees in China.
Humans ; Artificial Limbs ; Muscle, Skeletal ; Neurosurgical Procedures ; Plastic Surgery Procedures ; Prosthesis Implantation

Objective:To prepare the hydrogel scaffolds with different concentrations of laponite and compare their osteogenic properties.Methods:The scaffolds of gelatin/sodium alginate hydrogel into which laponite was added according to the mass ratios of 0%, 1%, 2%, and 3% were assigned into groups T0, T1, T2, and T3. In each group, the compressive modulus was measured and the leaching solution for 24 h extracted to measure the ion release. Bone marrow mesenchymal stem cells (BMSCs) were cultured in the extract medium from each group and common medium (blank group) ( n=3) in the in vitro experiments to determine the expression of osteogenic genes Runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and type I collagen after 7 days of culture. In the in vivo experiments, the scaffolds were implanted into the femoral condyle defects in rats, and a blank group with no scaffolds was set. The bone repair in each group was evaluated by hematoxylin-eosin(HE) staining and immunohistochemical staining. Results:The compressive modulus in group T2 [(139.05±6.43) kPa] was significantly higher than that in groups T0, T1 and T3 [(68.83±3.76) kPa, (101.18±3.68) kPa and (125.40±3.28) kPa] ( P<0.05). The ion contents of lithium, magnesium and silicon released from the 24 h leaching solution in group T2 were (0.031±0.005) μg/mL, (3.047±0.551) μg/mL and (5.243±0.785) μg/mL, insignificantly different from those in group T3 ( P> 0.05) but significantly larger than those in group T1 ( P>0.05). The in vitro experiments showed that the expression levels of Runx2, ALP and type I collagen in group T2 were 1.59±0.11, 2.02±0.08 and 1.06±0.17, significantly higher than those in the other groups ( P<0.05). HE staining showed that the implanted hydrogel was tightly bound to the bone tissue. Immunohistochemical staining showed that the numbers of Runx2 and osteocalcin positive cells in group T2 were significantly higher than those in the other groups. Conclusions:With ideal biocompatibility, hydrogel scaffolds with different concentrations of laponite can slowly release the decomposed ions of lithium, magnesium and silicon to promote the osteogenic differentiation of BMSCs and the repair of bone defects in vivo. A 2% concentration of laponite in the hydrogel scaffolds may result in the best results.

Objective:To characterize the biological activity of fibroblasts on the surface of titanium alloy sheets with different ridge widths by investigating the effects of ridge widths on the adhesion, proliferation and differentiation of fibroblasts.Methods:Five groups of titanium sheets with ridge widths of 50 μm, 80 μm, 100 μm, 150 μm and 200 μm were prepared, with all the groove depths being 10 μm. The titanium sheets with no ridges were taken as a control group. After fibroblasts were incubated on the sheets, states of their adhesion were observed by scanning electron microscopy (SEM) at different time points. CCK-8 cell proliferation test and immunofluorescence staining were used to observe proliferation and shape of the cells. The effects of ridge widths on adhesion of fibroblasts were evaluated by Vinculin immunofluorescence staining, and the effects of ridge widths on expression of α-smooth muscle actin ( α-SMA) by immunofluorescence. Results:SEM showed that the cells adhered to the ridges on the titanium sheets 48 hours after inoculation. In the groups with smaller ridge widths (from 50 μm to 150 μm), the cells were slender in shape and grew along the ridge direction. CCK-8 indicated that different ridge widths had no significant effect on the proliferation of fibroblasts between the 6 groups ( P>0.05). Immunofluorescence staining showed that the cells arranged in an orderly direction along the ridges; the long axis of the cells in the 50 μm group showed the best consistency with the extending direction of the ridge, with significant differences among the 6 groups ( P<0.05). The Vinculin test found that the secretion of cell adhesion protein was concentrated in the ridge and semi-quantitative analysis showed that the 50 μm group had the most Vinculin secretion, with significant differences among the 6 groups ( P<0.05). The α-SMA test showed that the ridge width had a regulatory effect on the myogenic differentiation of fibroblasts, and the 50 μm group had the strongest expression of α-SMA, with significant differences among the 6 groups ( P<0.05). Conclusions:Modification of ridges on the surface of titanium sheets may affect arrangement, adhesion and myogenic differentiation of fibroblasts. The ridges of 50 μm in width may lead to stronger polarized arrangement of fibroblasts, more secretion of adhesion-related protein and more pronounced myogenic differentiation of fibroblasts.

Objective:To prepare biomimetic tissue engineering scaffolds of gelatin/sodium alginate/laponite composite hydrogel loaded with BMSCs by 3D biological printing technique，and explore the osteogenic effect of 3D printing on hydrogel scaffolds containing bone marrow mesenchymal stem cells（BMSCs）.Methods:BMSCs were routinely extracted and identified by flow cytometry. Gelatin，sodium alginate and laponite were mixed and then BMSCs were added to prepare cell-containing composite hydrogel scaffolds using 3D bioprinting. Non-printed scaffolds containing cells were prepared by injection molding method. In vitro，the prepared scaffolds were divided into the printing group with cells and non-printing group with cells according to whether they were printed，with 12 samples per group. Another simple cell culture group was set as control. Then，the internal structure of the composite hydrogel was observed by scanning electron microscope，and the expansion rate and water content of the scaffolds were measured by freeze-drying method. At day 3 after culture，the growth status of BMSCs was observed by phalloidine staining. cell counting kit（CCK）-8 assay was used to detect cell activity in scaffolds at days 1，3，and 7 after culture and RT-PCR to detect the expression of osteogenesis related genes Osterix，osteocalcin（OCN）and collagen I at days 7 and 14 ofter culture. In vivo，four groups were set according to printing or not and whether containing cells or not：printing implant group with cells，non-printing implant group with cells，printing implant group without cells and non-printing implant group without cells，with 9 samples per group. Scaffolds in four groups were implanted to the posterior gluteal muscle pouches（random on left or right）of 36 8-week-old SD rats，respectively. The samples were taken X-ray images at 2，4 and 8 weeks after operation，respectively. The osteogenic differentiation of tissues at 8 weeks was observed by HE and Masson staining. Results:The flow cytometry showed that the cells were BMSCs. Internal pores of hydrogels were obvious，and cells stretched freely in the pores. Differences of the swelling rate and water content were not statistically significant between printing group with cells［（1，039.37±30.66）%，（91.21±0.26）%］and non-printing group with cells［（1，032.38±35.05）%，（91.16±0.28）%］（ P>0.05）. At day 3 after culture in vitro，the cells grew well in the hydrogel. After culturing for 1 day in vitro，there was no significant difference in absorbance between printing group with cells and non-printing group with cells（ P>0.05）. At day 3 after culture，there was no significant difference in absorbance between printing group with cells and non-printing group with cells，but both groups showed a higher level than simple cell culture group（ P<0.05）. At day 7 after culture，the absorbance in printing group with cells（2.72±0.17）was higher than that in non-printing group with cells（2.35±0.11），and both of which were higher than that in simple cell culture group（1.95±0.12）（ P<0.05）. At day 7 after culture in vitro，there was no statistically significant difference in the expression of osteogenic differentiation-related genes between printing group with cells and the non-printing group with cells（ P>0.05），but they were all higher than those in simple cell culture group（ P<0.05）. At day 14 after culture in vitro，the expression of osteogenesis-related genes Osterix（1.650±0.095），OCN（2.725±0.091），collagen I（2.024±0.091）in printing group with cells were higher than those in non-printing group with cells（1.369±0.114，2.174±0.198，1.617±0.082，respectively）and those in simple cell culture group（1.031±0.094，1.116±0.092，0.736±0.140，respectively）（ P<0.05）. After implantation for 2 weeks in vivo，with no statistically significant difference in the gray values of X-ray films in each group（ P>0.05）. At weeks 4 and 8 after implantation，the gray values of X-ray films in printing implant group with cells and non-printing implant group with cells were higher than those in printing implant group without cells and non-printing implant group without cells（ P<0.01）. At 8 weeks after implantation，HE staining showed that the scaffolds were degraded in different degrees and immersed with cells，with collagen production seen in Masson staining as well. Conclusions:Composite hydrogel scaffolds can provide a good three-dimensional environment for BMSCs growth. 3D bioprinting can promote the proliferation and osteogenic differentiation of BMSCs in hydrogel scaffolds. In addition，BMSCs-loaded scaffolds can be degraded slowly in vivo with good ectopic osteogenic ability.

Development and application of stem cells and their related technologies have paved new ways for prevention and treatment of orthopedic diseases. Application of stem cells for clinical treatment of bone defects is extremely promising, fracture, nonunion and osteonecrosis of the femoral head (ONFH) in particular. However, promotion of clinical stem cell therapy still faces difficulties and lacks corresponding standards. This article reviews clinical researches on stem cell therapy for bone injury and summarizes the injury types, cell types, cell numbers and their clinical efficacy, hoping to provide references for clinical treatment of bone injury with stem cells.

Objective:To explore the significance of digital orthopedic technology in surgical plan for spinal tumor and the preliminary outcomes of 3D printed vertebral bodies in spinal tumor surgery.Methods:The clinical data of 2 patients were retrospectively analyzed who had had a 3D printed vertebral body implanted at Center of Orthopaedics, Shenzhen Hospital from June 2018 to December 2019. One was a 32-year-old male, diagnosed with cervical neurinoma; the other was a 27-year-old female, diagnosed with giant cell tumor of lumbar bone. 3D virtual reconstruction of tumor and surrounding structures was established via Mimics software for surgical plan. Virtual osteotomy was simulated, their disease models and guide templates were 3D printed, and their metal artificial vertebral bodies were 3D printed after personalized design of the vertebral body diameter, porosity and procedures of reconstruction and fixation. Lesion resection and prosthesis implantation were carried out in accordance with the preoperative plan. After operation, the motor function of cervical or lumbar vertebrae, tumor recurrence, and spinal stability reconstructed were regularly observed.Results:Resections and reconstructions went uneventfully in both cases. The 2 patients were followed up for 21 and 13 months respectively. Their postoperative images showed that their 3D printed vertebral bodies fitted the neighboring vertebral bodies well. The spinal stability was reconstructed without any loosening or periprosthetic osteolysis, and the tumors were removed completely with no recurrence in both cases. Their spinal motor function was satisfactory.Conclusions:Digital orthopedic technology can offer accurate guidance in the treatment of spinal tumors. It is necessary to consider local physiological anatomy in personalized design of a metal vertebral body 3D printed. Clinical application of 3D printed metal vertebral bodies is a new strategy for spinal reconstruction following spinal tumor resection.

Objective: To establish an efficient classification and treatment system for limb long bone defects. Methods: Based on the length of bone defect, soft tissue injury and wound infection, a new classification and treatment system was proposed with reference to Gustilo-Anderson classification for open fractures and Orthopedic Trauma Association (OTA) classification. Results: We divided the limb long bone defects into 3 types, each of which was subdivided into 4 subtypes depending on concomitant soft tissue defect and/or infection. Type Ⅰ are bone defects less than 4 cm in length, including type Ⅰa (simple bone defects with a limited extent), type Ⅰb (bone and soft tissue defects), type Ⅰc (bone defects with infection) and type Ⅰd (bone defects with infection and soft tissue defects). Type Ⅱ are bone defects ranging from 4 to 10 cm in length, including type Ⅱa (simple bone defects with a large extent), type Ⅱb (bone and soft tissue defects), type Ⅱc (bone defects with infection) and type Ⅱd (bone defects with infection and soft tissue defects). Type Ⅲ are bone defects larger than 10 cm in length, including type Ⅲa (simple bone defects with a very large extent), type Ⅲb (bone and soft tissue defects), type Ⅲc (bone defects with infection) and type Ⅲd (bone defects with infection and soft tissue defects). Conclusion Our new classification and treatment system for long limb bone defects is more efficient and intuitive, facilitating clinical diagnosis and treatment of limb long bone defects.

Objective: To compare the biomechanical performance between the single- versus double-threaded cannulated screws in the treatment of femoral neck fractures of Pauwels type Ⅲ. Methods: Models of femoral neck fracture of Pauwels type Ⅲ (70°) were made of the Sawbone synthetic composite femurs. All specimens were divided into 2 groups (n=12). Group A was fixated with single-threaded cannulated screws and group B with double-threaded cannulated screws, both in an inverted triangle configuration. The screws ranged from 90 to 95 mm in length and from 7.3 to 7.5 mm in diameter. All the specimens were subjected to axial stiffness and failure load tests with 7° valgus (simulating normal two-legged weight-bearing stance) and 25° valgus (simulating normal one-legged weight-bearing stance) and torsion test as well. The 2 groups were compared in the torques at axial stiffness angles of 1°, 2°, 3°, 5° and 7°. Results: Group B had significantly greater axial stiffness at 7° valgus and 25° valgus (89±26 N/mm and 128±37 N/mm) and failure load (1,154±368 N) than group A did (36±12 N/mm and 47±16 N/mm; 688±94 N) (P< 0.05). The torques increased with the increase in rotation angle in both groups. However, the torques in group B (3.26±0.96, 4.16±1.23, 4.64±1.13, 5.59±1.26 and 6.53±1.47 N·m) were all significantly larger than in group A (1.44±0.19, 2.03±0.41, 2.33±0.62, 2.74±0.87 and 3.05±1.07 N·m) (P<0.05). Conclusion Double-threaded cannulated screws may provide better biomechanical stability than single-threaded ones, due to their substantial improvement in anti-compression and anti-rotation performance.

Objective: To evaluate the effect of 3DBody software assisted problem-based learning (PBL) teaching in orthopedic teaching. Methods: Undergraduates of clinical medicine from grade 2013 who had internship in our hospital were divided into experimental group and control group. Undergraduates in the experimental group were taught by 3DBody software assisted PBL teaching, with designed questions and the method of using 3DBody software handing to students before class. While undergraduates in the control group were taught by traditional teaching, with the use of textbooks and multimedia courseware. Examination scores of theory and probation were compared between the two groups. Questionnaires were used to evaluate the subjective perception of different teaching method among the participants in each group. Results: Scores of theoretical examination in the experimental group (84.6±5.9) were higher than those in the control group (73.2±6.1); scores of probation examination in the experimental group (17.7±2.1) were significantly higher than those in the control group (12.7±1.9); the degree of satisfaction in the experimental group (9.2±0.8) was significantly higher than that in the control group (7.2±1.3); all differences were statistically significant (P<0.05). Conclusion 3DBody software assisted PBL teaching can significantly improve the effectiveness of orthopedic teaching and enhance students' learning initiative and interest, which is worth promoting.