[Total knee replacement with ceramic femoral components: a national prospective multicenter study of clinical and radiological outcomes].
ABSTRACT The purpose of this prospective multicenter study was to evaluate the clinical and radiological outcomes of an unconstrained bicondylar total knee prosthesis with a new ceramic femoral component made of BIOLOX® delta.
Fifty patients underwent cemented total knee arthroplasty in three hospitals/centers. Clinical and radiological evaluations were undertaken preoperatively and at 3 as well as 12 months postoperatively using the HSS, WOMAC, and SF-36 scores.
During 12 months follow-up three patients had to undergo revision surgery due to non-implant-related reasons (infection, periprosthetic fracture, and retropatellar replacement). The mean preoperative HSS score amounted to 56.2±11.0 points. At 3 and 12 months follow-up the mean HSS score was 75.5±11.5 and 83.6±10.9 points, respectively. Therefore, HSS and WOMAC scores improved significantly from preoperative values at both postoperative evaluations. The first significant improvement of SF-36 score was seen after 12 months. Radiolucent lines around the femoral ceramic components were found in one case.
Subsequent long-term studies must be carried out in order to clarify the potential benefits of ceramic femoral components and confirm the good early clinical result. Moreover, the specific material properties of ceramic implants must be considered during implantation.
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ABSTRACT: Hypersensitivity reactions to implant materials have become more important in total knee replacement (TKR). The purpose of this retrospective comparative study was to evaluate the clinical and radiological outcomes of unconstrained bicondylar total knee prostheses with and without anti-allergic titanium(niobium)nitrite (Ti(Nb)N) coating. Twenty-four patients (25 TKRs) underwent a preoperative clinical evaluation and then a postoperative evaluation after 26.2 months in the allergy group treated with coated implants (n=13 implants) and after 24.5 months in the control group treated with uncoated implants but identical geometry (n=12) using HSS, WOMAC and SF-36 scores. Radiological evaluations were performed using standard anterior-posterior (a.p.) and lateral X-rays. During follow-up two patients of the allergy group had to undergo revision surgery due to non-implant-related reasons. A comparative analysis of both study groups showed a significant difference in the HSS scores at both evaluation time points (MW test p≤0.050); these findings are remarkable since the control group had a significantly lower score preoperatively (54.0 vs 65.0 points) and a significantly higher score (82.5 vs 75.0 points) postoperatively. The preoperative and postoperative WOMAC and SF-36 scores were comparable in both groups (MW test p≥0.052), although the postoperative increase in the score for the allergy group was lower. The radiological results were comparable in both groups and were unlikely to influence the results. This clinical study demonstrates the restricted outcome in postoperative function and quality of life in the allergy group compared to the control group.The Open Orthopaedics Journal 10/2011; 5:354-60. DOI:10.2174/1874325001105010354
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ABSTRACT: PURPOSE: A certain failure mode using a newly developed cemented ceramic femoral component in total knee replacement was observed in clinical application, i.e. fracture of the femoral component during intraoperative impaction. This may be caused by unintentional deflection of the saw blades during cutting with consecutive higher resection angle of the distal femur than desired, leading to bending of the femoral component during implantation. A finite-element-analysis was carried out to simulate implantation of the femoral component and to evaluate the influence of distal femur preparation on implant stress. SCOPE: We developed and validated a numerical model of the ceramic femoral component including a contact formulation which allowed calculating the principal stresses of the implant during implantation onto the resected femur. The analysis considered different anterior and posterior resection angles with a total of 17 variations. By increasing the femoral resection angle in the finite-element-model it could be shown that a deviation of three degrees from the intended resection angle can cause critical stress amounts during implantation. CONCLUSIONS: When implanting the ceramic component in total knee arthroplasty, the femoral resection angles should be prepared very precisely, in particular anterior saw blade deflection has to be avoided. The implant manufacturer increased implant safety through an additional resection template. Moreover, the impaction of the ceramic femoral component during cementing was not further recommended by using a hammer.The Knee 04/2012; 19(6). DOI:10.1016/j.knee.2012.03.014 · 1.70 Impact Factor
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ABSTRACT: Polyethylene wear is a key contributor to long-term failure in total knee arthroplasty. Oxidized zirconium alloy was created as a bearing surface for total joint arthroplasty in an attempt to address this concern. Oxidized zirconium has shown considerable improvements over existing materials in several key areas related to component longevity, including resistance to roughening, wear reduction, frictional behavior and biocompatibility. This review aims to summarize the current use of oxidized zirconium alloy in knee arthroplasty, as well as the possible advantages and downsides of this material.Expert Review of Medical Devices 07/2012; 9(4):409-21. DOI:10.1586/erd.12.30 · 1.78 Impact Factor