Mid-term survival of the Optimys short stem: A prospective case series of 500 patients

BACKGROUND In recent years,there has been an increase in the number of total hip arthroplasty procedures in the younger patient population.This active group has higher expectations of their prosthesis in comparison to the older population,and there is a greater physical demand for the prosthesis.Short femoral stems were in-troduced to retain proximal bone stock and joint biomechanics and became more common to implant in this specific population.Currently,the long-term survival and functional outcomes of various short stems are still being investigated in different clinics.AIM To determine the 5-year survival of the Optimys hip stem.METHODS This was a prospective multicenter cohort study of 500 patients conducted in two hospitals in the Netherlands.All patients received the Optimys short stem(Mathys Ltd,Bettlach,Switzerland).The primary outcome measure was survival of the hip stem,with revision as the endpoint.The secondary outcome measurements included patient-reported outcome measures(PROMs).Kaplan-Meier analysis was used to calculate the 5-year survival rate.Log-minus-log transformation was performed to calculate the 95%confidence interval(95%CI).Mixed model analyses were performed to assess the course of the PROMs during the 1st 2 years after surgery.Analyses were modeled separately for the 1st and 2nd years to calculate the yearly change in PROMs during both follow-up periods with accompanying 95%CIs.RESULTS The mean age of the total 500 patients was 62.3 years(standard deviation:10.6)and 202 were male(40%).At a median follow-up of 5.5 years(interquartile range:4.5-6.7),7 patients were deceased and 6 revisions were registered,for infection(n=3),subsidence(n=2)and malposition(n=1).This resulted in an overall 5-year survival of 98.8%(95%CI:97.3-99.5).If infection was left out as reason for revision,a stem survival of 99.4%(95%CI:98.1-99.8)was seen.Baseline questionnaires were completed by 471 patients(94%),317 patients(63%)completed the 1-year follow-up questionnaires and 233 patients(47%)completed the 2-year follow-up.Both outcome measures significantly improved across all domains in the 1st year after the operation(P<0.03 for all domains).In the 2nd year after surgery,no significant changes were observed in any domain in comparison to the 1-year follow-up.CONCLUSION The Optimys stem has a 5-year survival of 98.8%.Patient-reported outcome measures increased significantly in the 1st postoperative year with stabilization at the 2-year follow-up.

Review of Researches on Agricultural Industry Chain at Home and Abroad

Management of agricultural industry chain is the main form of modern agricultural industrialization. Integration and optimization of agricultural chain have great significance in deepening the reform in the countryside,quickening the development of agricultural modernization and establishing new system of agricultural management. Based on the theory sources and contents of agricultural chain as well as the current researches at home and abroad,this paper hackles and concludes information technology,logistics management and food safety and quality in foreign agricultural chain as well as the organization model,operation mechanism,integration and optimization,promotion and extension,financing and risk prevention,influencing factors as well as performance evaluation in domestic agricultural chain and offers relevant review in order to provide further reference for future researches.

The Chinese Urban-rural Dual Economic Structure Model and Analysis

Based on the characteristics of urban-rural dual economic structure in China,we build a dynamic endogenous urban-rural dual economic model closely linked to China's reality,and carry out mathematical economics analysis of optimized conditions for urban and rural sectors. The main results show that:(i) The labor growth rate of urban-rural sectors must be greater than the time discount rate,or else there would be a vicious cycle of diminishing returns in the sectors;(ii) The accumulation rate of physical capital and human capital of urban-rural sectors,and the rate of technological progress,need to be greater than the corresponding depreciation rate plus the time discount rate,otherwise there would be a vicious cycle of diminishing returns in the sectors;(iii) The low accumulation rate in the rural sector,and the occurrence of labor outflow,human capital loss and lack of investment,will expand income gap between urban and rural areas,which is a reason for solidification of urban-rural dual economic structure.

Calcar-guided short-stem total hip arthroplasty: Will it be the future standard? Review and perspectives

Short stems in total hip arthroplasty(THA)are becoming increasingly popular.In Germany,already 10.4%of all primary THAs are performed using a cementless short stem.The concept of modern,calcar-guided,short stems aims for an individualized reconstruction of the hip anatomy by following the calcar of the femoral neck,a bone-and soft-tissue-sparing implantation technique,and physiological loading.The stem design uses either metaphyseal fixation alone or additional diaphyseal anchoring,depending on the stem alignment and indication.These individualized anchorage types increase the potential indications for the safe use of a short stem.The design features may account for potential advantages of current short stem implants compared with earlier shortstem designs,particularly in cases of reduced bone quality or osteonecrosis of the femoral head and femoral neck fractures.The implantation technique,however,requires distinct knowledge regarding the characteristics of varus and valgus positioning,with the potential for clinical consequences.A learning curve for surgeons new to this technique must be taken into account.Cortical contact with the distal lateral cortex appears to be crucial to provide sufficient primary stability,and the use of intraoperative imaging to identify“undersizing”is highly recommended.Current results of several national registries indicate that calcarguided short stems are among the most successful implants in terms of mid-term survivorship.However,long-term data remain scarce.This review introduces the characteristics of calcar-guided short-stem THA and summarizes the current evidence.