Objective To study the changes of CDH1 gene promoter CpG island methylation and its clinical significance in patients with esophagus and stomach double primary carcinoma(ESDC).Methods The expression of CDH1 gene methylation in cancerous tissues and adjacent cancerous tissues in 18 cases of ESDC were detected using methylation-specific PCR method. Results Eighteen patients were endoscopically diagnosed as ESDC between Jan. 2007 and Sep. 2009 in the 4th Hospital Affiliated to Hebei Medical University. The positive methylation of CDH1 gene in tissues of esophageal squamous cell carcinoma (ESCC)and adjacent cancer were 66.7% and 33. 3%, respectively, with significant difference (χ2= 4. 167, P = 0. 031). Whereas the positive methylation of CDH1 gene in tissues of gastric carcinoma (GA) and adjacent cancer were 77.8% and 44.4%, respectively, without statistical difference (χ2=1.786, P= 0. 180). There was no significant difference (P=0. 500) in positive rate of CDH1 gene methylation between ESCC tissues and GA tissues in same individual with ESDC. For 18 patients with ESDC, consistent change of CDH1 methylation in tissues of two kinds of cancers was found in 16 patients with a total agreement of 88.9 % (positive agreement of 66.7 % and negative agreement of 22. 2%). Statistical analysis showed a significant correlation between two groups (P = 0. 005). Conclusion In patients with ESDC, there is a high consistency of CDH1 methylation change, between ESCC and GA,which suggests that two kinds of cancer may have similar risk factors and molecular mechanisms.

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 evaluate the rate of basicervical fractures and document their diagnosis and treatment.Methods: From January 2005 to May 2016,28 basicervical fractures of the 832 trochanteric fractures were collected and evaluated.The patients were treated with multiple screws,dynamic hip screw (DHS),intramedullary nail.Via the operation time,postoperative hospitalization,loss of blood duration the operation,hidden blood loss,total blood loss,mean union time and the final follow-up Harris hip score,the characteristics of different internal fixations were compared and analyzed.Results: The incidence of basicervical fractures was 3.37％ (28/832) in our study.In the intramedullary nail group (16 patients),the operation time was 55 (20,120) min,the postoperative hospitalization was 3(2,7) d,the intraoperative blood loss was 50(5,100) mL,the hidden blood loss was 533.37 (376.19,987.15) mL,and the total blood loss 627.35 (406.19,1037.16) mL.The union time and final follow-up Harris score were 6 (3,9) months and 90.25 (74,100) min.In the DHS group (8 patients),the operation time was 87.5 (65,115) min,the postoperative hospitalization was 5.5 (2,17) d,the intraoperative blood loss was 100 (50,300) mL,the hidden blood loss was 278.11 (202.43,849.97) mL,and the total blood loss 580.19 (368.55,899.97) mL.The union time and final follow-up Harris score were 5.5 (4,12) months and 85.5 (84,87) min.In the multiple screws group (4 patients),the operation time was 47.5 (35,75) min,the postoperative hospitalization was 5 (2,12) d,the intraope-rative blood loss was 20 (2,70) mL,the hidden blood loss was 150 (100.00,412.01) mL,and the total blood loss 195.00 (120.00,414.01) mL.The union time and final follow-up Harris score were 4 (4,6) months and 80 (61,97) min.The patients treated with multiple screws and intramedullary nail had a shorter operation time than the DNS group,but no obvious difference was found between the other two groups (P=0.367).Postoperative hospitalization had no significant difference among the three groups.The intraoperative bleeding was more in the DHS group,the other two groups had no significant difference (P=0.100).However,the hidden blood loss was more in the intramedullary nail group,the other two groups had no significant difference (P=0.134).The total blood loss in the intramedullary nail group was more than multiple screw group,similar to the DHS group (P=0.483).One patient treated with multiple screws underwent internal fixation failure three months after operation.The mean union time and final follow-up Harris scores had no significant difference among the three groups (P>0.05).Conclusion: Through this study,we found that the incidence of basicervical fractures is low.Fractures with no shift can be confirmed by preoperative X-ray.For displaced fractures,preoperative CT + 3D reconstruction is recommended.Surgical treatment by closed reduction and internal fixation with DHS or intramedullary nail is shown to be very effective.

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.

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 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 compare the efficacy of anterior-posterior and posterior-anterior screw fixation for posterior malleolar fractures surgery.Methods A retrospective analysis of 376 cases of posterior malleolar fractures treated with lag screws from January 2011 to October 2022 with more than 12 months of follow-up period was conducted.The patients were divided into two subgroups based on the thickness of the fracture fragment,with 167 cases in the small fracture subgroup having a fracture fragment thickness＜17 mm(screw thread length)and 209 cases in the large fracture subgroup having a fracture fragment thickness ≥ 17 mm.Each subgroup was further divided into anterior-posterior and posterior-anterior groups based on the direction of screw fixation in the posterior malleolar fracture surgery.In the small fracture subgroups,there were 74 cases in the anterior-posterior group and 93 cases in the posterior-anterior group.In the large fracture subgroup,there were 88 cases in the anterior-posterior group and 121 cases in the posterior-anterior group.The American Orthopaedic Foot and Ankle Society(AOFAS)ankle-hindfoot score was measured at the last follow-up.The displacement of the fracture fragment in the direction of the fracture line(Dn)and perpendicular to the fracture line(Dt)were measured on the first day after surgery and at the last follow-up,and the displacement of the fracture fragment was calculated,which was the difference between Dn+Dt at the last follow-up and Dn+Dt on the first day after surgery.Results On the first day after surgery,X-ray showed no significant difference in Dn and Dt between the anterior-posterior and posterior-anterior groups in both of the small and large fracture subgroups(P＞0.05).The entire group was followed up for 12-85 months,with an average of 19.3 months.In the small fracture subgroup,the displacement of the fracture fragment in the posterior-anterior group[(0.11±0.19)mm]was superior to that in the anterior-posterior group[(0.19±0.21)mm;P=0.011],and the AOFAS score was also superior to that in the anterior-posterior group[(80.2±8.4)points vs.(76.2±8.6)points,P=0.003].In the large fracture subgroup,there was no significant difference in fracture displacement between the posterior-anterior group[(0.11±0.18)mm]and the anterior-posterior group[(0.12±0.19)mm;P=0.630],and there was also no significant difference in AOFAS scores[(84.1±7.8)points vs.(82.8±7.6)points,P=0.246].Conclusions There is no significant difference in the reduction effect between anterior-posterior and posterior-anterior lag screw internal fixation for posterior malleolar fractures in trimalleolar fractures.For patients with fracture thickness＜17 mm,posterior-anterior fixation is superior to anterior-posterior fixation;for patients with fracture thickness ≥17 mm,there is no significant difference in the efficacy between anterior-posterior and posterior-anterior fixation.

Objective:To investigate the clinical effect and safety of reduction and fixation for the anterior glenoid fracture through an axillary approach.Methods:Two autopsy specimens (a total of 4 shoulder joints) were used to simulate the surgery of open reduction and internal fixation to treat anterior glenoid fracture through an axillary approach. Specimens were placed in the lateral decubitus position. An incision was made in the posterior axillary line to expose the lateral side of the scapula through the interval ahead of the latissimus dorsi muscle. Attended to the separation and protection of the axillary nerve, posterior humerus artery, thoracic dorsal nerve, and scapular artery. The surgical area of the axillary approach was divided into the upper "quadrilateral area" and the lower "trilateral area", which exposed the anteroinferior glenoid, neck, and the full length of lateral border of the scapula. Thirteen cases (7 males and 6 females) were involved in this study, all patients were diagnosed with anterior glenoid fracture and treated by open reduction and internal fixation through the axillary approach between April 2018 and December 2020. Constant-Murley score and Disabilities of the Arm, Shoulder and Hand (DASH) were used to evaluate the clinical efficacy.Results:Thirteen patients were enrolled for final analysis, which included 12 right cases and 1 left case. The average age was 50.38±13.74 years (range 24-67 years). All 13 patients were classified as Ideberg type Ia fracture. Anatomical buttress plates were used in 5 cases, cannulated screws combined with metacarpal plates in 7 cases, and distal radius plate in 1 case. The average length of follow-up was 13.00±5.97 months (range 6-26 months). No delayed union or malunion in all cases at the last follow-up visits. The average of Constant-Murley score was 62.46±10.26 points (range 45-83) and the DASH score was 27.56±9.76 points (range 14.14-43.33) at the three months follow up visits. At 6 months postoperatively, the Constant-Murley score was 80.85±8.32 points (range 65 to 90) and the DASH score was 11.47±8.56 points (range 0 to 35.00). Constant-Murley score at the final patient's follow-up visit was 84.54±8.95 points (range 70-95), and the DASH score was 10.94±8.67 points (range 1.67 to 33.33 points). The joint function gradually recovered with time. The functional scores at 3 months, 6 months after surgery, and final follow-up visit had significant differences ( P<0.05). Conclusion:The axillary approach is a safe and feasible approach for the treatment of the anterior glenoid fracture. This approach exposes the anteroinferior glenoid and the lateral border of the scapula, which reduces rotator-cuff injury and achieves anatomic reduction and strong fixation of the fracture. The axillary approach surgery also allows early functional physiotherapy after surgery.

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.