Characteristics of percentile value changes in body composition of children and adolescents aged 7 to 18 in Beijing / 中国学校卫生

Objective@#To analyze the trend of percentile changes in body composition among children and adolescents aged 7 to 18 by gender and age, and to provide a scientific basis for reference value.@*Methods@#A stratified cluster random sampling method was used to select 1 585 children and adolescents from September to December 2020. Use the GAMLSS to estimate the P 25 , P 50 and P 75 percentile value of gender, age specific body fat percentage (BF%), fat mass index (FMI) and fat free mass (FFM).@*Results@#In different age groups, body fat percentage of boys with normal nutritional status peaked at around 10-year old, among them, body fat percentage of 10-year old P 25 , P 50 and P 75 were 22.2%, 26.1% and 30.1%, respectively. Body fat percentage of obese boys was at a high level. Among girls, body fat percentage under different nutritional status did not change. With the increase of age, fat mass index plateaued slightly in normal and overweight boys. However, in obese boys, with the increase of age, FMI gradually increased with the increase of percentile, while the value of FMI gradually decreased in girls. Whether in boys or girls, with the increase of age, fat free mass index shows an increasing trend, and boys increase faster.@*Conclusion@#Under different nutritional status, there are differences in the percentile value of body fat percentage, fat mass index and fat free mass by gender and age, which can provide a scientific basis for reference value of body composition in children and adolescents.

Total arthroscopic internal drainage technique for the treatment of popliteal cyst / 中国骨伤

OBJECTIVE@#To compare the clinical effects of total arthroscopic internal drainage and arthroscopic combined with posterior small incision in the treatment of popliteal cyst.@*METHODS@#From January 2015 to January 2017, 60 patients with popliteal cyst were treated, including 29 males and 31 females, aged 30 to 65(47.8±2.5) years old, with a course of disease (8.5±4.2) months. Among them, 30 cases received total arthroscopic internal drainage for popliteal fossa cyst(total arthroscopic group), 30 cases received arthroscopic combined with posterior small incision for popliteal fossa cyst(arthroscopic combined with small incision group). The operation time, intraoperative bleeding volume, incision length, Rauschning and Lindgren grade 0 recovery rate and Lysholm score were compared between the two groups.@*RESULTS@#Twenty-nine patients in total arthroscopy group were followed up, and 28 patients in arthroscopy combined with small incision group were followed up for 8 to 20(12.8±2.1) months. Operation time: total arthroscopic group(45.32±5.71) min, arthroscopic combined small incision group (44.56±3.85) min; Rauschning and Lindgren grade 0 recovery: 23 cases in total arthroscopic group, 22 cases in arthroscopic combined small incision group; postoperative Lysholm score: total arthroscopic group 84.5±11.2, arthroscopic combined small incision group 83.2±12.7; there was no significant difference between the two groups(>0.05). Intraoperative bleeding volume: total arthroscopic group(5.32±1.25) ml, arthroscopic combined small incision group(20.75±8.18) ml; incision length: total arthroscopic group (1.51±0.34) cm, arthroscopic combined small incision group (7.34±0.75) cm; the difference between the two groups was significant(<0.05). At the last follow-up, the knee joint was examined by magnetic resonance imaging, and no recurrence of cyst was found.@*CONCLUSIONS@#Total arthroscopic internal drainage and arthroscopic combined with posterior small incision technique for popliteal fossa cyst with intra-articular lesions have the same clinical effect, but less trauma and faster recovery.

Musculoskeletal multi-body dynamic simulation on patient-specific total knee replacement during right-turn gait / 医用生物力学

Objective To develop a musculoskeletal multi-body dynamic model of the patient-specific total knee replacement (TKR), and to simulate knee joint biomechanical characters of the patient during right-turn gait. Methods Based on the musculoskeletal dynamic software AnyBody and the method of force-dependent kinematics as well as the related data from a patient with TKR, the corresponding patient specific lower extremity musculoskeletal multi-body dynamic model was constructed and then used to simulate the right-turn gait of the patient. The knee contact forces, motion, muscle activations and ligament forces were predicted simultaneously by inverse dynamics analysis on such right-turn gait. ResultsThe root mean square error of the predicted average tibiofemoral medial contact force and lateral contact force were 285 N and 164 N, respectively, and the correlation coefficients were 0.95 and 0.61, respectively. The predicted average patellar contact force was 250 N. The predicted contact forces and muscle activations were consistent with those in vivo measurements obtained from the patient. In addition, the model also predicted the average range of tibiofemoral rotations of flexion-extension, internal-external, varus-valgus as 3°-47°, -3.4°-1.5°, 0.2°--1.5°, and the average range of tibiofemoral translations of anterior-posterior, inferior-superior, medial-lateral as 2.6-9 mm, 1.6-3.2 mm, 4.2-5.2 mm, respectively. The predicted average peak value of the medial, lateral collateral ligament force and posterior cruciate ligament force were 190, 108, 108 N, respectively. Conclusions The developed model can predict in vivo knee joint biomechanics, which offers a robust computational platform for future study on the failure mechanisms of knee prosthesis in clinic.

Fabrication of scaffold with controlled porous structure and flow perfusion culture in vitro / 生物工程学报

3D Scaffolds with controlled porous structure were designed and fabricated by utilizing CAD and rapid prototyping techniques. A flow perfusion bioreactor, which allowed exposure of the culture cells to low levels of mechanical stimulation by fluid flow-induced shear stress, was developed in our lab. The scaffolds were pre-designed and the negative images of the designs were used to build the molds on a stereolithography (SL) apparatus with epoxy resins. Calcium phosphate cement paste was cast into the molds. And after pyrolysis, the 3D scaffolds with controlled internal pore architectures were obtained. Rabbit osteoblasts were seeded in 3D porous scaffolds, cultured in the flow perfusion bioreactor with media flow rate set at 2 mL/min and 6-well plates. At 3, 7, and 14 days, scanning microscopic evaluation showed excellent growth on the surface of scaffolds and poor viability of cells within microchannels in static cultures. In flow perfusion bioreactor, there was greater cellularity throughout the scaffolds and abundant deposition of extracellular matrix. Cells were also seen throughout the internal microchannels of scaffolds. These results represent that better mass transport of oxygen and nutrient occurred in the flow perfusion bioreactor and cells distribution in 3D porous scaffolds was improved.

Construction of three-dimensional finite element model of human edentulous maxilla and cranial skeleton / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To develop an effective and feasible method to construct three-dimensional finite element model of the whole edentulous maxilla and cranial skeleton.</p><p><b>METHODS</b>Based on three-dimensional computer aided design model which was constructed by multi-slices helical CT scanning data of a male's head in specialized software, three-dimensional finite element model of edentulous maxillary and cranial skeleton was established; the stresses distribution in maxilla was investigated under occlusal load with computer simulated a complete overdenture.</p><p><b>RESULTS</b>The three-dimensional finite element model of edentulous maxilla and cranial skeleton had favorite similarity in geometry, the distributions of stresses in maxilla and the wall of maxillary sinus could be clearly observed.</p><p><b>CONCLUSIONS</b>The study verifies that this three-dimensional finite element modeling method is feasible and effective.</p>

A new custom-made artificial articular cartilage of femoral condyle based on rapid prototyping technique: a case report / 中华外科杂志

<p><b>OBJECTIVE</b>To design and manufacture a new custom-made artificial articular cartilage of femoral condyle based on rapid prototyping technique and explore a method to solve the necroses of allocartilage in hemi joint allotransplantation.</p><p><b>METHODS</b>Design the new custom-made artificial articular cartilage of femoral condyle. The allograft and the patient distal femurs were scanned with Picker 6000 spiral computed tomography (CT) with 1.0 slice thickness and pitch of 1.5, reconstructed the distal femurs in Voxel Q image workstation with volume rendering technique. Then downloaded the transaxial 2D image data to personal computer at 0.1 mm interval and converted it into 2D digitized contour data by using image processing software developed by our team. The 3D wire frame and solid images of femoral condyle could be reconstructed when the 2D digitized contour data were input into image processing software Surfacer 9.0 (Imageware Company, USA). Subsequently based on the clinical experience and the need of design, the 3D contour image of articular cartilage was extracted from the surrounding. Based on the extracted 3D contour image, the computer-aided design (CAD) of the custom-made artificial articular cartilage was accomplished in Surfacer software, converted the CAD model into RP data format. Standard triangularization language, imported into the LPS600 rapid prototyping machine (Hengtong Company, Xi'an Jiaotong University, China), and the resin prototype was achieved. Then the resin model was used as a positive mould to build up a silica gel negative mould, the negative mould was sent to the factory to manufacture Ti-6Al-4V alloy articular cartilage through ordinary mould-melted founding process. Finally, the whole metal cartilage was completed after melting two special cages on it. A patient was selected to clinical applying.</p><p><b>RESULTS</b>A new custom-made artificial articular cartilage of femoral condyle was made. It was press-fit well to the subchondral bone of the allograft bone. The patient's one and half year follow-up result was excellent.</p><p><b>CONCLUSIONS</b>We design and manufacture a new custom-made artificial articular cartilage of femoral condyle based on rapid prototyping technique. The result shows that the manufacturing process has the advantage of rapidness and precision that are very important for individualized artificial implant manufacturing. The artificial articular cartilage is press-fit well and could be a good idea to solve the necroses of allocartilage in hemijoint allotransplantation.</p>

Reconstruction correction to Reconstrction of mandibular bone defects by using the techniques correction to teachniques of the reverse engineering and rapid prototyping / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility of designing and fabricating customized titanium bone substitutes to restore mandibular bone defects using reverse engineering (RE) and rapid prototyping (RP) techniques.</p><p><b>METHODS</b>Titanium tray for mandibular defects were designed and fabricated through multi-step procedures of reverse engineering and rapid prototyping, then in operation it was filled with cancellous bone and fixed.</p><p><b>RESULTS</b>The bone substitutes fabricated by this method had been successfully put into clinical use for maxillofacial surgery in 2 patients and got a satisfactory result.</p><p><b>CONCLUSIONS</b>Reverse engineering combining with rapid prototyping could accomplish the design and manufacture of implant for the restoration of mandibular bone defects.</p>

Effect of recombinant human basic fibroblast growth factor on angiogenesis during mandible fracture healing in rabbits / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the effect of recombinant human basic fibroblast growth factor (rhbFGF) on angiogenesis during mandible fracture healing in rabbit.</p><p><b>METHODS</b>Fifty adult white rabbits were used for animal model and randomly divided into a control group (25 rabbits) and an experimental group (25 rabbits). The membranous complex of rhbFGF and bovine type I collagen was prepared and implanted into the rabbit mandible fracture site under periosteum. The animals were sacrificed on 7, 14, 28, 56 and 84 days respectively after operation and the whole mandibles were harvested. The expression of factor VIII related antigen (F8-RA) in callus was examined with immunohistochemical staining.</p><p><b>RESULTS</b>The amounts of microvascular formation in calluses in the rhbFGF-treating group on days 7, 14, 28 and 56 were more than those of the control group (P<0.01).</p><p><b>CONCLUSIONS</b>The results indicated that rhbFGF could stimulate microvascular formation during mandible fracture healing in rabbits.</p>