Objective:To investigate the application effect of the comprehensive innovative teaching model with "3D printed model combined with visual surgical simulation" as the core in the clinical teaching of extremity bone defects.Methods:The physicians who participated in the clinical management of patients with extremity bone defects in Department of Orthopedics, Peking University Third Hospital, from March 2019 to December 2021 were selected as subjects and were divided into standardized training group with 52 physicians and refresher physician group with 58 physicians. Teaching and training was performed for the special disease of extremity bone defects, including basic knowledge teaching, dressing change for infected wounds, multidisciplinary discussion, digital surgical simulation, and practical surgical operation. The assessment indices for teaching quality included the assessment of theoretical knowledge and clinical skills, the objective evaluation of the clinical ability of patient management, and an investigation of the degree of satisfaction. SPSS 22.0 was used for the t-test and the chi-square test. Results:After training, both groups had significant increases in the assessment scores of theoretical knowledge [(32.4±6.7）and (42.2±3.8)] and clinical practice skills [(19.6±2.0), (20.8±2.2), (20.5±2.5), (21.5±2.3)]( P<0.05). After training, the standardized training group had significant increases in the scores of six objective evaluation indicators [(8.3±0.8) vs. (6.9±1.1), (7.4±0.7) vs. (6.3±1.5), (7.2±1.3) vs. (5.0±1.4), (7.9±1.2) vs. (4.0±1.5), (8.4±0.8) vs. (6.4±1.6), (40.3±2.6) vs. (28.6±2.4)]( P<0.01), while the refresher physician group had significant improvements in four aspects, i.e., the understanding of extremity bone defects [(8.1±0.9) vs. (7.2±1.1)], the self-confidence in facing complex extremity bone defects [(8.1±1.2) vs. (6.6±0.9)], spatial thinking ability in repair surgery for bone defects [(8.6±0.8) vs. (7.3±0.9)], and overall clinical performance in actual management of patients with bone defects [(41.4±2.3) vs. (37.3±1.8)] ( P<0.01). The satisfaction score for this comprehensive innovative teaching model was (95.3±3.2) points in the standardized training group and (94.8±2.8) points in the refresher physician group. Conclusions:The comprehensive innovative teaching model with "3D printed model combined with visual surgical simulation" as the core can significantly improve the basic knowledge and clinical skills of physicians in a short period of time and meet the needs for learning surgical techniques and advanced diagnosis and treatment concepts among refresher physicians.

Objective:To characterize the injuries suffered by athletes in snow events other than alpine skiing in the Zhangjiakou Zone of the Olympic Winter Games Beijing 2022, in order to provide insights for prevention of sports injuries and preparation of large-scale winter sports events.Methods:The medical records were retrospectively collected of all athletes who had been treated at Beijing University Third Hospital Chongli within the closed loop of the Zhangjiakou Zone during the Winter Olympics and Paralympics (from November 21, 2021 to April 5, 2022). The incidence, severity and part of the injuries were analyzed, as well as the medical treatment process.Results:In the Zhangjiakou Zone, a total of 1,188 athletes participated in the Winter Olympic Games, with an injury incidence of 2.9% (34/1,188), while 420 ones participated in the Winter Paralympic Games, with an injury incidence of 1.7% (7/420). The average daily medical visits were the highest during the Winter Olympics phase (1.16 visits per day), and their emergency severity index (ESI) ranged from level 3 to level 4. The department of orthopedics was visited the most (92.7%, 38/41). Lower limb injuries accounted for the highest proportion (53.7%, 22/41), with the knee ones accounting for 36.6% (15/41) of all injuries. Most of the athletes with ESI level 3 received splint fixation (62.5%, 5/8), while those with ESI level 4 mostly received observation and follow-up (57.6%, 19/33). A total of 57 radiological examinations were performed in the 41 athletes. X-ray was used the most frequently on a single day (5.00 times) while magnetic resonance imaging was per day on average (0.16 times). The transfer time for the athletes injured was (27.4±8.8) min which was not influenced by the 4 weather conditions (cloudy, sunny, light snow, and cloudy) ( P=0.374). Conclusions:The incidence of injuries during the Beijing Winter Olympics in the Zhangjiakou Zone was lower than that in other areas of the Beijing Winter Olympics and in previous Winter Olympics. There were no serious life-threatening cases. The imaging examination resources and transfer speed in the Zhangjiakou Zone were able to meet the medical needs of athletes at all stages of the Beijing Winter Olympics and Paralympics. Athletes should pay attention to protection of their lower limbs during skiing competitions.

Objective:To analyze and summarize the clinical effects of 3D printed porous titanium-alloy prosthesis implantation in the treatment of long bone defects of lower extremities.Methods:We retrospectively studied the clinical cases with lower extremity bone defect treated by 3D printed porous titanium prostheses from December 2017 to November 2021. 18 patients who were followed up for more than 12 months were included in this study. The enrolled patients included 12 males and 6 females, with an average of 48.9±22.5 years (range, 13-79 years), and an average body mass index of 23.1±4.3 kg/m 2 (range, 17.2-27.1 kg/m 2). There were 14 osteomyelitis-derived bone defects and 4 nonunion-derived bone defects. The bone defect locations included 10 cases of femur and 8 cases of tibia. The average bone defect distance was 13.9±9.7 cm (range, 5.8-31.2 cm), and the proportion of the defect length to the long bone (femur of tibia) was average 33.7%±16.8% (range, 15.0%-63.0%). The clinical efficacy was comprehensively evaluated through gross observation, imaging evaluation, changes in the total length of lower extremities and long bones, femorotibial angle (FTA) measurement, lower extremity functional scale (LEFS), satisfaction, complications and other indicators, focusing on the stabilization mechanism of the prosthesis and the regeneration of new bone. Results:All 18 patients were followed up for 12-35 months, with an average of 16.3 months. Postoperative X-rays at 1, 3, 12 and 24 months showed that new bone could gradually creep along the prosthesis surface. The preoperative bone defect length of long bone and total length of lower limb were respectively 39.4±4.0 cm and 80.5±5.7 cm, which were different from those of the healthy side by 1.6±1.0 cm and 1.5±1.1 cm. One week after implantation, the length of long bone and lower limb was 39.9±3.5 cm and 80.9±6.2 cm, respectively, and the average difference was 1.0±0.6 cm and 0.9±1.1 cm compared with the healthy side. At the last follow-up, the length of long bone and lower limb was 39.7±3.6 cm and 80.9±7.8 cm, with an average difference of 1.8±1.1 cm and 1.0±0.7 cm from the healthy side. There were no significant differences in the length of long bone and lower limbs at the three time points before surgery, one week after surgery and the last follow-up ( F=0.12, 0.04; P>0.05). The average FTA of the affected limb was 174.7° (173.9°, 175.5°), 175.2°(173.5°, 176.4°), and 175.0°(173.5°, 176.3°) at three time nodes, before surgery, one week after surgery and the last follow-up, respectively, and there was no significant statistical difference in pairwise comparison ( Z=0.01, P>0.05). Patients had a mean LEFS score of 50 (46, 51) at the last follow-up, significantly higher than the preoperative score of 20 (17, 21) ( Z=-5.56, P<0.001). The mean satisfaction score of the 18 patients at the last follow-up was 9.7. Two patients (11.1%) had screw fractures but all 3D printed porous titanium alloy prostheses remained stable without significant loosening or displacement. Two patients (11.1%) had nail channel infection of external fixator, all patients with channel infection were cured by intravenous antibiotics combined with local disinfection and dressing change. Conclusion:The implantation of 3D printed porous titanium-alloy prosthesis could efficiently and safely repair the long bone defects of the lower extremities. The prosthesis could maintain stable in the early and middle postoperative period. The length of the long bones and lower limbs did not change significantly with the weight-bearing and functional exercise of the limbs. The new bone could gradually crawl and grow from both ends of the defect, and the patient's limb function recovered significantly, and the patient's satisfaction was high.

Objective: To investigate psychological and behavioral responses and the prevalence of acute stress disorder (ASD) among the injured from a serious road traffic accident. Methods: The injured persons at ages of 7 years and older from a serious road traffic accident were enrolled, and individuals with severe injury were exclude. Participants' gender, age, educational level, marital status, injury severity, family member's injury and death during the accident and psychological and behavioral status were collected. The prevalence of ASD was estimated using a semi-structured interview and the ASD Scale, and the factors affecting the development of ASD were identified using a multivariable logistic regression model. Results: A total of 132 survivors participated in psychological crisis assessment, including 82 men (62.12%) and 50 women (37.88%) and with a mean age of (46.50±18.57) years. There were 6 participants without obvious trauma (4.54%), 113 with mild injury (85.61%) and 13 with moderate injury (9.85%), and there were 6 participants with death of their family members during this accident. Insomnia, anxiety, flashback and fear were predominant psychological and behavioral responses, with prevalence rates of 42.42%, 35.58%, 26.52% and 23.48%, respectively. The prevalence of ASD was 30.30% among participants, and a higher rate of ASD was detected among women than among men (52.00% vs. 17.07%; χ2=17.940, P<0.001). The detection of ASD was higher among participants with death of their family members than among those without death of their family members (83.33% vs. 26.98%; χ2=8.370, P=0.004), and a higher detection rate of ASD was seen among participants with moderate injury (61.54%; χ2=6.786, P=0.034). Multivariable logistic regression analysis showed a higher risk of ASD among females (OR=7.764, 95%CI: 3.187-18.915) and those with a high educational level (high school/technical secondary school, OR=6.896, 95%CI: 1.030-46.152; diploma and above, OR=71.583, 95%CI: 4.145-1 236.270). Conclusions Insomnia and anxiety are predominant psychological and behavioral responses following serious road traffic accidents, and women and individuals with a high educational level present a high risk of ASD, which requires to be given timely psychological crisis interventions.

Objective:To evaluate the curative effects of Masquelet technique and 3D printing in repair of Cierny-Mader type Ⅳ long bone osteomyelitis.Methods:A retrospective study was conducted of the 8 patients who had been treated at Department of Orthopaedics, The Third Affiliated Hospital to Peking University for Cierny-Mader type Ⅳ osteomyelitis of the lower extremity from June 2017 to December 2019. They were 6 males and 2 females, aged from 27 to 79 years (average, 54.6 years). The defects involved femoral shaft in 5 cases, femoral metaphysis in one, tibia shaft in one, and tibial metaphysis in one. The defect lengths ranged from 7.7 to 15.5 cm, averaging 10.2 cm. Stage one was local infection control and temporary stability reconstruction using Masquelet technique, stage two design and 3D printing of the prosthesis and stable pattern design, and stage three prosthesis implantation and rehabilitation. The ranges of motion of the knee and ankle were recoded postoperatively and the functions evaluated using the Johner-Wruhs scores.Results:The average follow-up time for the 8 patients was 12.6 months (from 6 to 18 months). The total treatment time from the first admission to the last discharge ranged from 62 to 125 days (average, 91.0 days), the time for stage one from 13 to 57 days (average, 28.7 days), that for stage two from 30 to 87 days(average, 48.3 d), and that for stage three from 28 to 84 days (average, 63.0 days). The infection was controlled and there was no recurrence, implant loosening or breakage. Seven patients were capable of full weight-bearing at 14.7 days (from 4 to 42 days) after surgery. One patient recovered full weight-bearing 6 months after surgery due to severe osteoporosis. Fine functional recovery was achieved in the 8 patients, with a range of motion from 0° to 100° for the knee and a range from 35° dorsal flexion to 40° toe flexion for the ankle. The Johner-Wruhs scores at the last follow-up showed 2 excellent, 5 good and one moderate cases.Conclusion:In repair of Cierny-Mader type Ⅳ long bone osteomyelitis, Masquelet technique and 3D printing can shorten the treatment process and allow for early recovery.

Objective:To investigate the efficacy and safety of programmed death-1 (PD1) inhibitor combined with transcatheter arterial chemoembolization (TACE) in the treatment of huge primary liver cancer.Methods:From June 2016 to December 2019, the clinical data of 31 patients with huge primary liver cancer enrolled in the Central Hospital of Lishui were retrospectively collected and analyzed. The tumor size ranged from 10.1 to 18.8 cm, with an average of (14.2±2.3) cm. The patients were divided into TACE group (TACE treatment, 18 cases) and combined group (one week after TACE, patients receiving a dose of 200 mg PD1 inhibitor administration every 21 days, 13 cases), according to whether patients receiving PD1 inhibitors. The patients were followed up. The disease control rate (DCR) were compared between the two groups using Mann-Whitney U test. The median overall survival (OS) and progression free survival (PFS) were calculated by Kaplan-Meier method. Results:The DCR in combined group (53.8%, 7/13) was higher than that in TACE group (22.2%, 4/18), and the difference was statistically significant ( Z=-2.13, P=0.04). The median PFS (5.0 months) in combined group was longer than that in TACE group (3.0 months), the difference was statistically significant (χ2=4.39, P=0.04). The median OS (15 months) in combined group was longer than that in control group (9 months), and the difference was statistically significant (χ2=5.51, P=0.02). Conclusion:The combine PD1 inhibitors with TACE is an effective and safe therapy for huge primary liver cancer.

Objective:To compare the short-term outcomes of femoral neck system (FNS) and dynamic hip screw (DHS) in the treatment of femoral neck fractures.Methods:A retrospective analysis was performed of the 105 patients with fresh femoral neck fracture who had been treated by FNS fixation from September 2019 to October 2020 or by DHS fixation from January 2018 to October 2020 at Department of Orthopaedics, The Third Hospital Affiliated to Peking University. In the FNS group of 54 cases, there were 18 males and 36 females with a mean age of (60.7±15.2) years; in the DHS group of 51 cases, there were 14 males and 37 females with a mean age of (63.3±13.2) years. The 2 groups were compared in terms of hospital stay, operation time, intraoperative blood loss, incision length, intraoperative fluoroscopy frequency, qualify of reduction, and femoral neck shortening length, Harris hip score and complications at the last follow-up.Results:The 2 groups were comparable due to insignificant differences in their preoperative general data or follow-up time ( P>0.05). In the FNS group, the median operation time [45.0 (40.0, 59.0) min], intraoperative blood loss [30.0 (20.0, 50.0) mL], incision length [4.0 (4.0, 5.0) cm], intraoperative fluoroscopy frequency [10.5 (9.0, 12.0) times] and hospital stay [2.0 (2.0, 4.0) d] were significantly superior to those in the DHS group [72.0 (55.0, 89.0) min, 50.0 (30.0, 50.0) mL, 7.0 (6.0, 8.0) cm, 18.0 (15.0, 19.0) times, and 3.0 (3.0, 6.0) d] (all P<0.05). There were no statistical differences between the 2 groups in quality of reduction, length of femoral neck shortening, failure rate of internal fixation or Harris hip score at the last follow-up ( P>0.05). There were no such surgical complications as deep infection or femoral head necrosis in either of the 2 groups. Conclusions:In the fixation of femoral neck fractures, both FNS and DHS may lead to fine short-term outcomes. However, compared with DHS, FNS exhibits advantages of simplicity, minimal invasion, less surgical trauma and intraoperative fluoroscopy frequency, and reduced operation time and hospital stay.

Objective:To investigate the efficacy and safety of short-term transcatheter arterial chemoembolization （TACE）-radiofrequency ablation （RFA） sequential therapy for advanced hepatocellular carcinoma (HCC).Methods:The clinical data of 117 patients with advanced HCC enrolled in the Central Hospital of Lishui from March 2010 to January 2019 were retrospectively analyzed. All patients received TACE and RFA sequential therapy. The patients were divided into 2 groups including short interval group (interval≤7 d, 61 cases) and long interval group (interval>7 d, 56 cases) according to interval between TACE and RFA. The difference of response rate was analyzed by Wilcoxon test. Kaplan-Meier survival curve was used to calculate the overall survival (OS) time and progression free survival (PFS) time.The risk factors of TACE-RFA sequential therapy were tested using Cox multivariate analysis. The complications in the two groups were compared using χ 2 test. Results:The response rate in the short interval group (72.1%, 43/61) was significantly higher than that in the long interval group (41.1%，23/56) with significant difference ( Z=-2.50, P=0.01). The median PFS in the short interval group (14.9 months) was longer than that in the long interval group (9.1 months). The difference of PFS survival curve between the 2 groups was statistically significant (χ2 =5.90, P=0.01).The median OS in the short interval group (34.7 months) was longer than that in the long interval group (20.3 months). The difference of OS survival curve between the 2 groups was statistically significant (χ2 =6.60, P=0.01). Cox multivariate analysis showed that tumor size [hazard ratio (HR)=2.42, P<0.01], cirrhosis (HR=2.04, P<0.01), interval (HR=0.44, P<0.01), aspartate aminotransferase (HR=1.71, P=0.03) were the independent risk factors for advanced HCC.There were no significant differences in the complication incidence between the 2 groups ( P>0.05). Conclusion:Short-term interval TACE-RFA sequential therapy as a protective factor is efficient and safe for advanced HCC treatment.

Objective:To establish an analytical method for the simultaneous determination of five fat-soluble vitamins in serum using isotope dilution ultra high performance liquid chromatography-tandem mass spectrometry (ID-UPLC-MSMS).Methods:Fat-soluble vitamins were obtained from serum samples which collected from Shanghai Tenth People′s Hospital between April 2019 and August 2019 by the extraction method, and were detected by ID-UPLC-MSMS. The performance of the method was verified by referring to the relevant documents of the Clinical and Laboratory Standards Institute (CLSI).Results:The ID-UPLC-MSMS method for the rapid detection of various fat-soluble vitamins in serum was proposed and successfully verified. The linear range of the method: vitamin A: 25-2 500 μg/L, 25(OH)D 2: 2-200 μg/L, 25(OH)D 3: 2-200 μg/L, vitamin E: 0.25-50 mg/L, vitamin K1: 0.1-20 μg/L. The intra- and inter-assay precision standard deviations of the five analytes were within ± 15%, and the accuracy of the test results of the 25(OH)D 2 and 25(OH)D 3 standards was 96.44%-102.37%. Conclusion:The performance of ID-UPLC-MSMS method for the simultaneous determination of five fat-soluble vitamins is satisying, and the result is accurate and reliable, which suggested it can be used for the clinical sample.

Objective: To identify the risk factors for failure of internal fixation with proximal femoral nail antirotation (PFNA) for reverse intertrochanteric hip fractures. Methods: A retrospective study was conducted of the 45 patients with reverse intertrochanteric hip fracture who had been treated with PFNA fixation from January 2006 through January 2018 at the Department of Traumatic Orthopaedics, The Third Affiliated Hospital to Peking University. They were 19 males and 26 females, aged from 19 to 97 years (average, 71.9 years). According to the AO/OTA classification, there were 7 cases of type 31-A3.1, 4 cases of type 31-A3.2 and 34 cases of type 31-A3.3. Fracture healing was judged according to the X-ray at the time of last follow-up. The patients were assigned into a healed group and a failed group. The 2 groups were compared in terms of gender, age, body mass index (BMI), mechanism of injury, AO classification, type of main fracture line, reduction method, reduction quality, status of lateral femoral wall and tip-apex distance. A multivariate logistic regression model was designed to analyse the dependent variable 'implant failure’ with a set of independent variables as risk factors. Results: The 45 patients were followed up for 12 to 62 months (average, 28.4 months). Implant failure was observed in a total of 6 patients (13.3%), 3 of whom had helical blade perforation, 2 main screw breakage, and one cut-out of helical blade. The single factor analysis revealed significant differences in reduction quality and type of main fracture line between the patients with successful fixation and those with failed fixation (P<0.05). The multiple logistic regression analysis identified poor reduction quality (OR=30.809, 95%CI: 1.052~902.298, P=0.047) and a transverse fracture line (OR=25.639, 95%CI: 1.636~401.917, P=0.021) as risk factors for implant failure. Conclusion Poor reduction quality and a transverse fracture line may be predictors of implant failure in reverse intertrochanteric hip fractures treated with PFNA fixation.