Objective:To explore the short-term outcomes of reconstruction of tumorous critical bone defects at femoral shaft with a 3D printed ultra-short stem with a porous structure.Methods:From September 2016 to June 2018, 8 patients underwent reconstruction of critical bone defects with a 3D printed ultra-short stem with a porous structure after resection of femoral shaft malignant tumor at Department of Orthopaedics, West China Hospital. There were 4 males and 4 females, with an average age of 36.9 years (from 11 to 61 years). Their preoperative Enneking staging was stage Ⅱb in all. There were 3 osteosarcomas, 2 Ewing sarcomas, 2 chondrosarcomas and one periosteal osteosarcoma. Preoperative CT/MRI image fusion technology was used to define the surgical boundary, design the guide plate and prosthesis, and perform surgical simulation. Tomosynthesis-shimadzu Metal Artefact Reduction technology was used to evaluate osseointegration. Complications and bone oncology prognosis of the patients were documented. The lower limb function of the patients was evaluated using Musculoskeletal Tumor Society (MSTS) 1993 scoring and knee range of motion.Results:The overall follow-up time ranged from 36 to 50 months, averaging 42.8 months. During operation one patient sustained a periprosthesis fracture, the union of which was followed up after wire assisted fixation. There was no local tumor recurrence, lung metastasis or death. The last follow-up revealed good osseointegration and basically isometric lower extremities in all cases. There was no such a complication as aseptic loosening of the prosthesis, deep infection or prosthesis fracture during the follow-up period. At the last follow-up in the 8 patients, the flexion range of the knee joint was 116.2°±9.1°, significantly improved compared with that before operation (98.8°±10.9°), and the MSTS score was (26.2±2.1) points, also significantly improved compared with that before operation [(21.6±1.8) points] ( P<0.05). Conclusions:Reconstruction with a 3D printed ultra-short stem with a porous structure is an accurate operation for femoral shaft tumorous bone defects. With careful preoperative design, intraoperative manipulation and strict postoperative follow-up management, this operation can lead to fine early curative outcomes for long shaft critical bone defects.

Objective To analyze the incidence characteristics and pathogen epidemic characteristics of respiratory tract children in Chongqing Kaizhou area. Methods A total of 5 328 children admitted to our hospital from January 2019 to December 2022 were selected as the research subjects. Indirect immunofluorescence method was used to detect 8 common respiratory pathogens in the serum of the children; Using SPSS 22.0 software, analyze the incidence characteristics and pathogen prevalence of 8 pathogens in respiratory tract children. Results (1) The highest detection rate was MP (χ²=12.141, P<0.05); (2) The detection rate of PM and PIV in the infant group was lower than that in the infant group and large group, The difference was statistically significant (χ²=7.923, P<0.05); (3) Eight pathogens IgM had the highest detection rate in the spring, Opposite in winter (χ²=1.872, P<0.05); (4) A total of 3 817 IgM antibody positive cases were detected in 5328 sick infants, The positive rate was 71.64%, There was a statistical difference between the sexes (χ²=3.928, P<0.05). Conclusion The detection rate of respiratory pathogens varies in age and sex, which is highest in spring, so pay attention to the respiratory tract infection in spring, focusing on the prevention and treatment of mycoplasma pneumoniae.