Objective To determine the biomechanical variation in full-length femoral stress pat-tern and periprosthetic femoral stress distribution after implantation either with Charnley Elite cemented prostlesis or Summit proximal porous cementless femoral prosthesis. Methods Three-dimensional finite element models of intact femur, Charnley Elite and Summit femoral prostheses were developed. The stress distributions on the femur and the implants were measured. Applied with hip joint loading and related muscles strength, the stress changes of an intact femur and those implanted with either Charnley Elite or Summit protheses, especially changes in proximal femur, were respectively quantitatively analysed. Results Com-pared with intact femur, there was no change of the full-length femur stress pattern in implantation of both implants, the areas of peak values were all presented at middle and lower regions of the femur, and femoral stress value levels were decreased with both implants. Both prostheses induced significant decrease of stress in the periprosthetic bone tissue, the most serious loss of stresses all appeared at femoral calcar, the stress-shielding rates of Elite and Summit prostheses were 90.8% and 95.3% respectively. The distributions of stress shielding of both prostheses were consistent each other, the Summit proximal porous cementless pros-thesis had more serious stress decrease than the Charnley Elite cemented prosthesis. Conclusion Implan-tation of both implants may cause significant stress shielding in the proximal femur. This may be related with periprosthetic bone loss and aseptic loosening of stems, and can be used to explain the mechanism of post-operative femoral fracture and thigh pain. Both implants designs need further improvement to reduce stress changes in proximal femur.

Objective To investigate the diagnostic value of knee skin temperature and serum soluble intercellular adhesion molecule-1 (sICAM-1) level in peri-prosthetic infection after total knee arthroplasty (TKA).Methods Thirty patients (11 males and 19 females,aged 59.3±9.5 years old) underwent primary TKA during November 2012 and October 2015.Ten patients with peri-prosthetic infection (3 males and 7 females,aged 60.9±8.2 years old) underwent two-stage revision TKA from November 2012 to October 2015.The interleukin-6 (IL-6),C-reactive protein (CRP),erythrocyte sedimentation rate (ESR),sICAM-1 in serum and the skin temperature in knee joint were recorded preoperatively (revision patients on diagnosis),at days 1,7 and at 1,3,6,12 months post-operatively.Results All of the 40 patients were followed up for 12 months.The serum CRP,IL-6 and ESR levels in the primary TKA group were normal preoperatively and increased after operation,reaching their peaks at 1-7 days postoperatively.These indexes then returned slowly to the normal levels within 3 months.The serum sICAM-1 level in the primary TKA group did not change significantly during the follow up.The serum levels of CRP,IL-6,ESR,and sICAM-1 in the revision group were significantly higher than that in the primary TKA group preoperatively (P＜0.05),IL-6,CRP,ESR returned slowly to the normal levels within 3 months after the second-stage revision,while the level of sICAM-1 returned to normal within 3 months after the first-stage revision.During whole follow-up after the second-stage revision,the level of sICAM-1 didn't change significantly.The preoperative mean differential temperature (MDT) in the primary TKA group was 0.73±0.62 ℃ preoperatively and elevated to 4.37±1.06 ℃ at 7 days postoperatively,which returned to the baseline within 6 months after primary TKA.The preoperative MDT in the revision group was 5.03±0.81 ℃,which was significantly higher than that in the primary TKA group (P＜0.05).The MDT returned to the normal level within 6 months after the second-stage revision TKA.Conclusion The change of MDT is in accordance with serum CRP,IL-6,and ESR,which together may predict the occurrence of infection.Serum sICAM-1 level may also be valuable in the diagnosis of peri-prosthetic infection.

Objective To explore the effect and factors of patellofemoral arthroplasty (PFA) for isolated patellofemoral osteoarthritis.Methods Data of 18 patients (3 males,15 females) with isolated patellofemoral osteoarthritis underwent PFA from March 2006 to December 2014 were retrospectively analyzed.There were 3 males and 15 females with a mean age of 54 years (range,46-74 years).It was strict to grasp the surgical indications according to the clinical symptoms,signs and imaging data preoperatively.11 patients were operated with AVON patellofemoral prosthesis (Stryker Inc.) and the other 7 patients were operated with the Gender Solutions patellofemoral prosthesis (Zimmer Inc.).Active and passive functional rehabilitation exercise was encouraged at the early stage after operation.Visual analogue scale (VAS) was 5.33±0.99 (range,4-7) and hospital for special surgery knee score (HSS) was 53.28±5.71 (range,44-63) before operation.Results The mean duration of follow-up was 63.98 months (range,6-104 months).VAS after operation for 1 and 3 months were 1.17±0.79 (range,0-3) and 0.72±0.67 (range,0-2),and the pain was almost relieved after 9 months.HSS after operation for 1,3,9 months were 70.06±6.33 (range,61-80),86.06±5.12 (range,77-95) and 91.39±4.83 (range,82-97).HSS score of the latest follow-up was 92.06±4.05 (range,84-97),which was improved obviously from the preoperative ones.The excellent and good rate was 100％ (excellent 15 cases,good 3 cases).The satisfactory rate was 94.4％ (17/18).Only one case got slightly knee pain when walking up and down the stairs after 2 years,and the pain was relieved after being administered with NSAIDs and rest.No incision infection,rupture,prosthesis supported bone fracture,prosthesis loosening and other complication was occurred during the follow-up period in the other patients.Conclusion The clinical outcomes of PFA are strictly related to surgical indications,implant design and appropriate surgical technique.Therefore,based on the appropriate PFA implants,strict surgical indications,appropriate patients,excellent operation skills and actively functional rehabilitation exercise,PFA could treat the isolated patellofemoral osteoarthritis effectively.

Objective To explore relationship between anterior knee pain after total knee arthroplasty and patella resurfacing and prosthesis design,and to evaluate which femoral prosthesis is more friendly with patella:Genesis Ⅱ or PFC knee prostheses.Methods Data of 145 patients (145 knees) who had undergone primary total knee arthroplasty for treating osteoarthritis were retrospectively analyzed.Posterior-cruciate-substituting total knee prostheses were used in all patients.Among 74 patients who had undergone patella resurfacing,Genesis Ⅱ knee prosthesis was used in 32 patients and PFC knee prosthesis in 42 patients.Among 71 patients who had not undergone patella resurfacing,Genesis Ⅱ knee prosthesis was used in 38 patients and PFC knee prosthesis in 33 patients.The Hospital for Special Surgery(HSS) score,patella score,patellar function score,range of motion of knee,anterior knee pain scale,and patient satisfaction were used to evaluate clinical outcomes.At the same time,the imaging results were evaluated by X-rays.Results 144 patients were successfully followed up for 21 to 43 months (average,33 months).There was no significant difference in incidence of anterior knee pain between the group with patella resurfacing and the group without patella resurfacing,while a significant difference was found between patients receiving Genesis Ⅱ knee prosthesis and those receiving PFC knee prosthesis.Four patients who had undergone total knee arthroplasty using PFC prosthesis underwent reoperation.There were no significant differences in postoperative HSS score,range of motion of knee and patient satisfaction between the Genesis Ⅱ group and the PFC group,while there were significant differences in patella score and patellar function score between them.Conclusion Postoperative anterior knee pain was related to the prosthesis design,rather than to the patella resurfacing.Genesis Ⅱ knee prosthesis was more friendly with patella than PFC knee prosthesis.

AIM: To explore the effects of glucocorticoids on fracture healing in a rat model of tibial fracture. METHODS: Sixty three months old female SD rats were divided into control and glucocorticoid-treated group. A glucocorticoid-induced osteoporosis model was established by intramuscular injection of prednisolone acetate (5 mg·kg~(-1)·d~(-1) for 3 weeks), in which the tibial was osteotomized by a wire saw as fracture healing model and internal fixed with a Kirschner pin. The rats were scarified at different time points after operation. The callus formation was monitored over a period of 6 weeks by histological method, bone mineral density (BMD) detection and biomechanical examination. Western blotting was used to measure the expression of type II collagen. RESULTS: A glucocorticoid-induced osteoporosis model was successfully established and conformed by BMD measurement. The formation of primary callus was observed in both groups 3 days after fracture. At 2 weeks after injury, the glucocorticoid-treated group had a lower BMD and less cartilage matrix as compared to control group. An increase in bone callus and chondrogenesis was observed at 4 to 6 weeks after fracture in glucocorticoid-treated group as compared to control group. The expression of type II collagen was delayed in glucocorticoid-treated group. Biomechanical measurement showed that the actual maximum load was increased by 35.8% in control group as compared to glucocorticoid-treated group at 6th week. CONCLUSION: These results indicate that chondrogenesis and transformation from cartilage callus to bony callus are delayed by glucocorticoids. The retardation of collagen Ⅱ production may be the reason for the inhibition of fracture healing.

Objective To investigate the risk factors related to the survival time of anti-protrusion cage in acetabular revision.Methods Data of 40 patients who had received acetabular revision using antiprotrusion cages between January 2002 and June 2010 were retrospectively analyzed.There were 16 males and 24 females,aged from 22 to 77 years (average,60.3 years).All patients were followed up for 12 to 82 months (average,39.2 months).According to the AAOS classification,there were 29 cases of type C and 11 cases of type D； while according to the Paprosky classification,there were 29 cases of type ⅢA and 11 cases of type Ⅲ B.The multiple regression analysis was utilized to investigate the relationships between different factors and anti-protrusion cage failure.The corresponding factors included gender,age,bone loss classification,superior or lateral migration of acetabular center of rotation,abduction angle,fixation manners (simple flange fixation or flange fixation plus transacetabular screw fixation),bone grafting techniques and cup type.Results At final follow-up,the average Harris score was 74.5±15.4.Two patients received rerevision due to prosthetic loosening.Obvious radiological loosening of prosthesis combined with pain was found in 2 cases.The statistical analysis indicated that superior migration of acetabular center of rotation,abduction angle and fixation manners were correlated with cup failure,especially when the superior migration was more than 8.5 mm or the abduction angle was larger than 53.5°.Flange fixation plus transacetabular screw fixation could reduce risk of cup failure.Conclusion There is a higher cup failure risk in acetabular revision using an anti-protrusion cage for patients with serious bone defect.However,implanting cup at the level of the true acetabulum as far as possible,decreasing abduction angle properly and using flange fixation plus transacetabular screw fixation can reduce cup failure risk.

ObjectiveTo investigate the prevalence of nonalcoholic fatty liver disease (NAFLD) and related abnormal indicators among taxi drivers in Shenzhen, China, and to provide a basis for scientific prevention and treatment of fatty liver disease. MethodsA total of 1752 taxi drivers who underwent physical examination in Shenzhen Longhua District People’s Hospital from May 2018 to June 2019 were selected, and related indicators were measured, including body mass index (BMI), blood pressure, fasting plasma glucose (FPG), total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and uric acid (UA). Liver ultrasound examination was also performed. The association between the prevalence rate of NAFLD and various biochemical parameters was analyzed. The t-test was used for comparison of continuous data between two groups, and the chi-square test was used for comparison of categorical data between two groups. ResultsThe prevalence rate of NAFLD among the taxi drivers was 51.66% (905/1752), and male drivers had a significantly higher prevalence rate than female drivers［57.94% (770/1329) vs 31.91% (135/423), χ2=9.209, P=0.027］. The taxi drivers with NAFLD had significantly higher abnormal rates of BMI, blood lipids, blood pressure, FPG, and UA than those without NAFLD (χ2=5.894, 7.126, 8.045, 8.909, and 10.373, P=0.047, 0.035, 0.030, 0.028, and 0.018). The taxi drivers with a BMI of ≥28 kg/m2 had a significantly higher prevalence rate of NAFLD than those with a BMI of 24.0-27.9 kg/m2 or a BMI of ＜24 kg/m2 (male: χ2=7.904 and 18.624, P=0.035 and 0.008; female: χ2=8.613 and 31.635, P=0.029 and 0.006). The taxi drivers with working years of ＞15 years had a significantly higher prevalence rate of NAFLD than those with working years of 11-15 years, 5-10 years, and ＜5 years (male: χ2=9.781, 13.546, and 18.052, P=0.024, 0.012, and 0.008; female: χ2=7.052, 9.847, and 12.157, P=0.036, 0.023, and 0.016). ConclusionThere is a high prevalence rate of NAFLD among taxi drivers in Shenzhen, and male drivers have a higher prevalence rate than female drivers. The prevalence rate of NAFLD is associated with the abnormal rates of hyperlipidemia, obesity, hyperglycemia, and hyperuricemia and the working years in driving.

OBJECTIVES: The long-term trends of cognitive function and its associations with physical performance remain unclear, particularly in Asian populations. The study objectives were to determine cognitive trajectories in middle-aged and elderly Chinese individuals, as well as to examine differences in physical performance across cognitive trajectory groups. METHODS: Data were extracted from the China Health and Retirement Longitudinal Study. A total of 5,701 participants (47.7% male) with a mean age of 57.8 (standard deviation, 8.4) years at enrollment were included. A group-based trajectory model was used to identify cognitive trajectory groups for each sex. Grip strength, repeated chair stand, and standing balance tests were used to evaluate physical performance. An ordered logistic regression model was employed to analyze differences in physical performance across cognitive trajectory groups. RESULTS: Three cognitive trajectory groups were identified for each sex: low, middle, and high. For both sexes, higher cognitive trajectory groups exhibited smaller declines with age. In the fully adjusted model, relative to the low trajectory group, the odds ratios (ORs) of better physical performance in the middle cognitive group were 1.37 (95% confidence interval [CI], 1.17 to 1.59; p<0.001) during follow-up and 1.40 (95% CI, 1.20 to 1.64; p<0.001) at the endpoint. The ORs in the high trajectory group were 1.94 (95% CI, 1.61 to 2.32; p<0.001) during follow-up and 2.04 (95% CI, 1.69 to 2.45; p<0.001) at the endpoint. CONCLUSIONS Cognitive function was better preserved in male participants and individuals with higher baseline cognitive function. A higher cognitive trajectory was associated with better physical performance over time.

Objective To evaluate the early stage effects of partial two?stage exchange (PTE) for infection after total hip arthroplasty (THA) in order to improve surgical treatment outcomes. Methods Twelve patients (7 males and 5 females) of infect?ed THA treated by PTE between September 2000 and February 2016 were included with an average of 59 years old (range, 40-74 years old). The femoral stem prosthesis was preserved when we ensured that it was not infected and with well fixation during opera?tion. The acetabular prosthesis was totally replaced. Furthermore, the secondary surgery was performed on patients who were free from infection for at least 3 months. At the follow?up duration, the pelvic X?ray was examined to access the presence of loosening of the prosthesis. The inflammatory index was recorded. Hip function was assessed by the Harris hip score, and the visual analogue score (VAS) and patient's subjective satisfaction were recorded by the questionnaire. Results All of the 12 patients were fol?lowed up for a mean of 33.3 months (range, 24-48 months). We achieved a 92% (11/12) success rate. One patient resuffered infec?tion, which was controlled after the second debridement. The preoperative Harris score of 12 patients was 23-57, with an average of 40.83±10.62. All patients had significant improvement in hip function after PTE. The Harris score reached 59.58±4.34 at one month after surgery, and reached 64.58±9.08 after three months and 86.75±4.58 at the last follow?up. There was significantly dif?ferent when compared with the preoperative Harris score. At the last follow?up, the length difference between the lower limbs was less than 1cm in all patients. Two patients did not complain of pain, while other 10 patients got a VAS score of less than 2 points. The patient's subjective satisfaction rating was 100%. Conclusion PTE could be a valuable alternative treatment for infection af?ter THA. The infection control rate and clinical outcomes are comparable to those of two?stage exchange.

Purpose: Oligometastatic non–small cell lung cancer (NSCLC) patients have been increasingly regarded as a distinct group that could benefit from local treatment to achieve a better clinical outcome. However, current definitions of oligometastasis are solely numerical, which are imprecise because of ignoring the biological heterogeneity caused by genomic characteristics. Our study aimed to profile the molecular alterations of oligometastatic NSCLC and elucidate its potential difference from polymetastasis. Materials and Methods: We performed next-generation sequencing to analyze tumors and paired peripheral blood from 77 oligometastatic and 21 polymetastatic NSCLC patients to reveal their genomic characteristics and assess the genetic heterogeneity. Results: We found ERBB2, ALK, MLL4, PIK3CB, and TOP2A were mutated at a significantly lower frequency in oligometastasis compared with polymetastasis. EGFR and KEAP1 alterations were mutually exclusive in oligometastatic group. More importantly, oligometastasis has a unique significant enrichment of apoptosis signaling pathway. In contrast to polymetastasis, a highly enriched COSMIC signature 4 and a special mutational process, COSMIC signature 14, were observed in the oligometastatic cohort. According to OncoKB database, 74.03% of oligometastatic NSCLC patients harbored at least one actionable alteration. The median tumor mutation burden of oligometastasis was 5.00 mutations/Mb, which was significantly associated with smoking, DNA damage repair genes, TP53 mutation, SMARCA4 mutation, LRP1B mutation, ABL1 mutation. Conclusion Our results shall help redefine oligometastasis beyond simple lesion enumeration that will ultimately improve the selection of patients with real oligometastatic state and optimize personalized cancer therapy for oligometastatic NSCLC.