BACKGROUND:The adjustment of force lines in open wedge high tibial osteotomy can affect the retroversion of the knee joint and the height of the patella.In addition,the adjustment of force lines in open wedge high tibial osteotomy is also different according to different varus deformity.At present,the difference of weight bearing line adjustment is still controversial for the correlation index of knee joint and the function of knee joint after surgery.OBJECTIVE:To investigate the effect of line adjustment area on postoperative knee function and joint kinematics during open wedge high tibial osteotomy.METHODS:Totally 76 patients with knee osteoarthritis who received open wedge high tibial osteotomy in Binzhou People's Hospital Affiliated to Shandong First Medical University from March 2022 to March 2023 were selected,including 33 males and 43 females,all on one knee.The lateral border of the tibial plateau was considered as 100％.The position of the central intercondylar ridge of the knee joint was 0％.The weight bearing line of the affected limb was divided into two groups according to the difference of the lateral plateau area of the affected limb:the area of the force line passing through the lateral plateau of the tibial plateau(0-29％)was classified as group A(n=39),and the area of the lateral plateau of the tibial plateau was classified as group B(n=37)by 30％to 40％.The changes of tibiofemoral angle,medial proximal tibial angle,posterior inclination of tibia,and patellar height before and after operation were analyzed.The symptoms and function of the knee were evaluated by the Numeric Rating Scale score and the Hospital for Special Surgery knee score.RESULTS AND CONCLUSION:(1)At 1 year after surgery,the posterior inclination of tibia and the medial angle of proximal tibia were increased in both groups(P＜0.05),and the tibiofemoral angle was reduced and patellar height was decreased in both groups(P＜0.05).The posterior inclination of tibia,medial proximal tibial angle,tibiofemoral angle,and patellar height were significantly different between the two groups at 1 year after surgery(P＜0.05).(2)The Hospital for Special Surgery knee scores of the two groups of patients at all times after surgery were better than those before surgery,and showed a gradually increasing trend(P＜0.05).There was no significant difference in the Hospital for Special Surgery knee scores 1 week and 3 months after surgery between the two groups(P＞0.05).Hospital for Special Surgery knee score of group B at 6 and 12 months after surgery was better than that of group A(P＜0.05).(3)The Numeric Rating Scale score after surgery showed a gradual downward trend(P＜0.05).No significant difference was detected between the two groups(P＞0.05).(4)The results show that the knee function and symptoms were significantly improved in the early and middle period after open wedge high tibial osteotomy,and the knee joint related parameters changed with the outward shift of weight bearing line.At 1-year follow-up,the functional recovery of knee joint in group B was better than that in group A.Long-term knee function and clinical differences after surgery need further follow-up study.

BACKGROUND:The adjustment of force lines in open wedge high tibial osteotomy can affect the retroversion of the knee joint and the height of the patella.In addition,the adjustment of force lines in open wedge high tibial osteotomy is also different according to different varus deformity.At present,the difference of weight bearing line adjustment is still controversial for the correlation index of knee joint and the function of knee joint after surgery.OBJECTIVE:To investigate the effect of line adjustment area on postoperative knee function and joint kinematics during open wedge high tibial osteotomy.METHODS:Totally 76 patients with knee osteoarthritis who received open wedge high tibial osteotomy in Binzhou People's Hospital Affiliated to Shandong First Medical University from March 2022 to March 2023 were selected,including 33 males and 43 females,all on one knee.The lateral border of the tibial plateau was considered as 100％.The position of the central intercondylar ridge of the knee joint was 0％.The weight bearing line of the affected limb was divided into two groups according to the difference of the lateral plateau area of the affected limb:the area of the force line passing through the lateral plateau of the tibial plateau(0-29％)was classified as group A(n=39),and the area of the lateral plateau of the tibial plateau was classified as group B(n=37)by 30％to 40％.The changes of tibiofemoral angle,medial proximal tibial angle,posterior inclination of tibia,and patellar height before and after operation were analyzed.The symptoms and function of the knee were evaluated by the Numeric Rating Scale score and the Hospital for Special Surgery knee score.RESULTS AND CONCLUSION:(1)At 1 year after surgery,the posterior inclination of tibia and the medial angle of proximal tibia were increased in both groups(P＜0.05),and the tibiofemoral angle was reduced and patellar height was decreased in both groups(P＜0.05).The posterior inclination of tibia,medial proximal tibial angle,tibiofemoral angle,and patellar height were significantly different between the two groups at 1 year after surgery(P＜0.05).(2)The Hospital for Special Surgery knee scores of the two groups of patients at all times after surgery were better than those before surgery,and showed a gradually increasing trend(P＜0.05).There was no significant difference in the Hospital for Special Surgery knee scores 1 week and 3 months after surgery between the two groups(P＞0.05).Hospital for Special Surgery knee score of group B at 6 and 12 months after surgery was better than that of group A(P＜0.05).(3)The Numeric Rating Scale score after surgery showed a gradual downward trend(P＜0.05).No significant difference was detected between the two groups(P＞0.05).(4)The results show that the knee function and symptoms were significantly improved in the early and middle period after open wedge high tibial osteotomy,and the knee joint related parameters changed with the outward shift of weight bearing line.At 1-year follow-up,the functional recovery of knee joint in group B was better than that in group A.Long-term knee function and clinical differences after surgery need further follow-up study.

Objective: To analyze the spatial clustering characteristics of HIV/AIDS among men who have sex with men (MSM) in Chongqing from January 2004 to December 2015 and understand the HIV/AIDS related behaviors among MSM by interview. Methods: Data related to MSM who were infected with HIV and whose present address were in Chongqing, were collected from Information System on the HIV/AIDS Prevention and Control. Information included the age when the information was inputted, address, occupation, education level, and marital status. The total number of MSM who were infected with HIV and reported was 6 604 in Chongqing. Those with unknown address were ruled out. The spatial autocorrelation analysis and the local spatial autocorrelation analysis were carried out by using ArcGIS 10.3. In addition, in November 2015 and May 2016, using a convenience sampling, we conducted one-on-one interviews among 23 MSM in the Chongqing Center for Disease Control and prevention. Inclusion criteria: Receiving voluntary counseling and testing in the urban area of Chongqing and willing to participate in the interview by oral informed consent; male and self-described as MSM. The content of the interview included basic information, sexual orientation, sexual role, the main place of making friends, the main place of sexual behavior, a long-term experience in other provinces and drug abuse. Results: The HIV/AIDS reported number in Chongqing from 2004 to 2015 showed an uptrend, except in 2010. The age distribution of 6 604 cases of HIV positive patients was mainly concentrated in the 15-34 years old, about 68.5% (4 522 cases). There was a positive spatial autocorrelation in MSM, except 2005 (Moran's I=-0.046, P=0.823), form 2004 to 2015, Global Moran's I values were 0.308, 0.254, 0.335, 0.683, 0.673, 0.558, 0.620, 0.673, 0.685, 0.654 and 0.649, respectively; all P values were <0.01. The result of local spatial autocorrelation analysis showed that high-high accumulation area development in Chongqing city was divided into two stages in 2004-2015, which were Yuzhong, Jiangbei, and Shapingba district in 2004-2007 and the expanded Jiulongpo, Nan'an, and Yubei district in 2008-2015. Qualitative interviews results revealed that the age of the respondents was 20-44, and the mainly way of making friends were using mobile phone App and internet (17 participants). Most of the participants (11 participants) were making friends in the bar. The majority of respondents would ask the friends or themselves to use condoms when meeting with them the first time (19 participants), and 8 of respondents reported that they would not use condoms when their old friends refused to use condoms. Conclusion The HIV infected MSM mainly aged between 15-34 years old and the spatial distribution of HIV/AIDS among MSM was clustered in economically developed main area in Chongqing. MSM began to make friends on the Internet, and could not adhere to using condom, which indicated that we should focus on internet intervention to find more efficacious interventions.

BACKGROUND:Simple pedicle screw fixation for thoracolumbar fractures has better outcomes, but there are some deficiencies, such as poor applicability for severe compression or burst fractures, strong vertebral pain, easy to cause vertebral wound denervation and paraspinal muscle injury, and slow recovery. OBJECTIVE:To investigate the clinical effects of pedicle screw fixation combined with artificial bone graft for the treatment of thoracolumbar fractures. METHODS:A total of 126 patients with thoracolumbar vertebral compression fractures, who had undergone pedicle screw fixation without bone graft (control group,n=62) and with bone graft (test group,n=64) were enroled. The fracture healing, anterior vertebral height ratio, sagittal Cobb angle, and loss rate of vertebral height after 6 months were observed by X-ray in the two groups. RESULTS AND CONCLUSION:Al patients were folowed up, and had complete fracture healing after 12-16 months. The anterior vertebral height and Cobb angle were both improved in the two groups at 1 week after operation (P < 0.01), but there was no difference between the two groups (P > 0.05). New bone formation was observed in the test group at 6 months after operation, and patients were pain-free; but the speed of bone formation was slower in the control group, and patients stil suffered from painful thoracolumbar fractures. There was no difference in the loss of anterior vertebral height and Cobb angle between the two groups (P> 0.05). These findings indicate that pedicle screw fixation combined with artificial bone graft lead to a better recovery in thoracolumbar fractures.

OBJECTIVETo study the effect of bleaching on the mechanical properties of human dentin.

METHODSThe finite element method (FEM) based the cohesive zone model had been employed to study the fracture resistance of human dentin. There types of dentin were considered, i.e. original dentin, dentin after direct-bleaching and indirect-bleaching.

RESULTSThe bleaching treatments had large impact on the crack growth resistance of human dentin. The initiation toughness (1.48 MPa x square root of m), growth toughness (3.90 MPa x square root of m x mm(-1)) and plateau toughness (3.25 MPa x square root of m) of human dentin were reduced to 1.29 MPa x square root of m, 3.45 MPa x square root of m x mm(-1) and 2.71 MPa x square root of m respectively after indirect-bleaching. The worst case was the direct-bleaching which causes significant reductions in the growth toughness (0.14 MPa x square root of m x mm(-1)) and plateau toughness (1.63 MPa x square root of m) respectively, while the initiation toughness remained the same as that after indirect-bleaching.

CONCLUSIONThe cohesive zone modeling is an effective tool in characterizing the fracture behavior of human dentin. Bleaching treatments reduce the crack growth resistance of human dentin and increase the risk of fracture of teeth.