The influence of head-neck and implant position on the range of motion after total hip arthroplasty

To study the influence of head-neck ratio and implant position on the range of motion (ROM) after total hip arthroplasty (THA).Methods In this study the author established a three-dimensional computerized model of hip joint and tested the range of motion of three different head-neck ratio after total hip arthroplasty.Results Range of motion after total hip arthroplasty depended on design parameters such as head-neck ratio,but also on the implantation parameters such as the cup’s inclination and antevertion,the stem’s antevertion and their combination of each other.Optimal range of motion required compliant position of total hip components.The range of motion increased with the enlarging of head-hnck ratio.Conclusion Higher head-neck ratio leads to optimal range of motion and decreased the prevalence of prosthetic impingement within compliant,well-defined combination of cup’s inclination,cup’s antevertion and stem’s antevertion depending on the intended ROM.Domestic magnesium-silicon jade total hip prosthesis has too low head-neck ratio to result in enough range of motion that fulfilled daily living after total hip arthroplasty.14 refs,4 figs,3 tabs.

Early clinical outcome and learning curve following unilateral primary total knee arthroplasty after introduction of a novel total knee arthroplasty system

BACKGROUND New implants for total knee arthroplasty(TKA)are continuously introduced with the proposed benefit of increased performance and improved outcome.Little information exists on how the introduction of a novel arthroplasty implant affects the perioperative and surgical outcome immediately after implementation.AIM To investigate how surgery-related factors and implant positioning were affected by the introduction of a novel TKA system.METHODS A novel TKA system was introduced at our institution on 30th November 2015.Seventy-five TKAs performed with the Persona TKA immediately following its introduction by 3 different surgeons(25 TKAs/surgeon)were identified as the Introduction Group.Moreover,the latest 25 TKAs performed by each surgeon prior to introduction of the Persona TKA were identified as the Control Group.A Follow-up Group of 25 TKAs/surgeon was identified starting 1-year after the end of the introduction period.Demographics,surgery-related factors and alignment data were recorded,and intergroup differences compared.RESULTS Following introduction of the novel implant,Persona TKA was utilized in 69%(71%),53%(54%),and 45%(75%)of primary TKA procedures by the three surgeons,respectively(Follow-up Group).Mean surgery time was increased by 28%(P<0.0001)and mean intra-operative blood loss by 25%(P=0.002)in the Introduction Group,while only the mean surgery time was increased in the Follow-up Group by 18%(P<0.0001).Overall alignment was similar between the groups apart from femoral flexion(FF)and tibial slope(TS).The number of FF outliers was reduced in the Introduction Group with a more pronounced decrease in the Follow-up Group.CONCLUSION Introduction of the new TKA implant increased surgical time and intraoperative blood loss immediately after its introduction.These differences diminished one year after introduction of the new implant.Fewer outliers with respect to FF and TS were seen when using the novel TKA implant.Further studies are needed to investigate if these differences persist over time and correlate with patient reported outcomes.

股骨近端防旋髓内钉螺旋刀片置入辅助定位器的临床应用

目的观察股骨近端防旋髓内钉螺旋刀片辅助定位器在实际临床应用中的精确性。方法将40例股骨转子间骨折患者按双盲法分为前20例为对照组,后20例为观察组。对照组接受常规股骨近端防旋髓内钉手术治疗,观察组接受股骨近端防旋髓内钉手术联合螺旋刀片辅助定位器手术治疗。记录2组螺旋刀片置入股骨颈标准位置的打入次数、手术持续时间、术中C形臂X线暴露次数,并通过测量螺旋刀片轴线与股骨头中心轴线偏离的角度(偏向角)评估其置入的准确性。结果观察组手术时间、X线暴露时间、螺旋刀片打入次数、偏向角均少于或小于对照组,差异有统计学意义(P<0.05)。结论股骨近端防旋髓内钉螺旋刀片辅助定位器可以更快、更准确地一次性置入螺旋刀片,并可以明显减少C形臂曝光次数,有效降低术中手术人员辐射损害。