Influence of Manufacturing Process of Warp-knitted Vascular Prosthesis on the Wall Homogeneity

This paper reports the evolution of textile structure and mechanical properties of vascular prosthesis in the level of the whole prosthesis and the constituent filaments with respect to the manufacturing process. The tubular wall of the prosthesis is divided circumferentially into three zones; basic line (BL), remeshing line ( RL) and guide line ( GL). Some heterogeneity has been observed on the tubular wall in terms of stitch structure of the prosthesis and linear density of the constituent filaments. The breaking position of the prosthesis under circumferential tensile localizes preferentially in remeshing line that is the weakest zone by warp knitting with double needle bed. Furthermore, the statistical differences of the mechanical properties of the filaments of zone RL, GL and BL have been confirmed too. It is predictable that the deterioration of prosthesis, under physiological loads (periodical pulse blood pressure etc.), could happen firstly in the weaker zone in vivo.

Personalized image-based templates for precise acetabular prosthesis placement in total hip arthroplasty:a pilot study

Objective：In order to achieve accurate implantation of the acetabular prosthesis in total hip arthroplasty（THA）,we designed individual templates based on a three-dimensional（3D） model generated from computed tomography（CT） scans.Methods：Individual templates were designed for 12 patients who underwent THA.A physical template was designed to conform to the contours of the patient＇s acetabulum and to confirm the rotation of the acetabular center.This guided the acetabular component orientation.Results：The preoperative and postoperative X-ray and CT scans were obtained to assess the location with respect to the accuracy of the acetabular component.For all patients,the abduction angle of the acetabular component was 46.7°to 54.3°and the anteversion angle was 11.3°to 18.5°Conclusions：The assessment of postoperative CT scans demonstrated higher accuracy of the acetabular component bore when used with the individual template.Therefore,the individual template can be an alternative to the computer-assisted navigation systems,with a good cost-performance ratio.

Does mismatch of the femoral component aspect ratio influence the range of knee flexion after posterior-stabi- lized total knee arthroplasty？

Objective： To study whether the range of knee flexion （ROF） is affected by geometrical mismatch of the femoral component and the resultant change in the pos- terior condylar offset （PCO） after high-flexion posterior-sta- bilized total knee arthroplasty （TKA）. Methods： One hundred osteoarthritic patients （50 males and 50 females） underwent femoral osteotomy by the ante- rior referencing technique. The PCO for each patient was measured from lateral radiographs before, during and 2 years after TKA. The thickness of the joint cartilage was mea- sured by magnetic resonance imaging before TKA and added onto the radiographic measurement. The relationship between changes in the PCO and improvements in the ROF before, during and 2 years after TKA were statistically analyzed. Results： Compared with the preoperative value, the PCO was reduced by （3.45±3.28） mm after TKA, with a significantly larger reduction observed in female patients than male patients （P〈0.05）. When examining the subject popu- lation as a whole, there was a significant positive correla- tion between PCO and ROF improvement during TKA （P〈 0.05）, but this improvement was not maintained 2 years after TKA （P〉0.05）. However, when male and female patients were analyzed separately, there was a significant positive correlation between PCO change and ROF improvement for both sexes at both time points （all P〈0.05）. Conclusions： Restoration of PCO plays an important role in the optimization of knee flexion even after posteriorstabilized TKA. Femoral components based on Caucasian anatomic characteristics could not match the native anatomy of distal femurs in Chinese population especially female Chinese. Rotated resection of distal femur with anterior referencing technique usually leads to a decreased PCO and therefore reduces maximal obtainable flexion.