Abstract：
OBJECTIVE: Polyethylene particles produced from metal-backed tibial (MBT) implants are understood to contribute to bone loss and component loosening. This, along with advanced surgical techniques, improved materials and increasing costs, has renewed interest in all-polyethylene tibias (APTs). We investigated peri-APT bone mineral density (BMD) in patients, expecting to find no differences between two post-operative values.
METHODS: Patients over 65 years, with BMI ≤ 37.5 kg/m2 and no previous joint replacements were recruited to have computer-navigated total knee arthroplasty using an APT. The study cohort (n = 27) had mean age of 71.9 (SD 4.35) and BMI of 31.2 (SD 3.8). The BMD examinations were performed 6 weeks and 18 months post-operatively. Six regions of interest (ROI) were identified on anterior/posterior and lateral dual-energy X-ray absorptiometry scans. For each ROI, BMD relative differences (RDs) were determined between limbs and RDs at the two time points were compared.
RESULTS: No differences were found between the RDs for any ROI. No revisions or complications were reported. At 18 months post-operatively, 79.2% of the cohort were very satisfied or satisfied with the outcome of their surgery and Oxford Knee Scores improved significantly compared to pre-operatively (p < 0.001). Mean knee range of motion was 102° (SD 10.7°), and mean leg alignment was 2.0° valgus (1-6°valgus).
CONCLUSIONS: Results from BMD analysis suggest that implants were well fixated without compromising function. We believe that using APTs with computer navigation is a viable cheaper option to MBTs for patients who are less active, have lower BMI and good bone quality.
METHODS: Patients over 65 years, with BMI ≤ 37.5 kg/m2 and no previous joint replacements were recruited to have computer-navigated total knee arthroplasty using an APT. The study cohort (n = 27) had mean age of 71.9 (SD 4.35) and BMI of 31.2 (SD 3.8). The BMD examinations were performed 6 weeks and 18 months post-operatively. Six regions of interest (ROI) were identified on anterior/posterior and lateral dual-energy X-ray absorptiometry scans. For each ROI, BMD relative differences (RDs) were determined between limbs and RDs at the two time points were compared.
RESULTS: No differences were found between the RDs for any ROI. No revisions or complications were reported. At 18 months post-operatively, 79.2% of the cohort were very satisfied or satisfied with the outcome of their surgery and Oxford Knee Scores improved significantly compared to pre-operatively (p < 0.001). Mean knee range of motion was 102° (SD 10.7°), and mean leg alignment was 2.0° valgus (1-6°valgus).
CONCLUSIONS: Results from BMD analysis suggest that implants were well fixated without compromising function. We believe that using APTs with computer navigation is a viable cheaper option to MBTs for patients who are less active, have lower BMI and good bone quality.
摘要：
目的：由金属支持的胫骨（MBT）植入物产生的聚乙烯颗粒被认为是导致骨丢失和组件松动的原因。这个,加上先进的外科技术，改善材料和增加成本，对全聚乙烯胫骨（APT）重新产生了兴趣。我们调查了患者的APT周围骨矿物质密度（BMD），期望发现两个术后值之间没有差异。
方法：65岁以上的患者，BMI≤37.5kg/m2,且之前未进行关节置换,使用APT进行计算机导航全膝关节置换术.研究队列（n=27）的平均年龄为71.9（SD4.35），BMI为31.2（SD3.8）。术后6周和18个月进行BMD检查。在前/后和外侧双能量X射线吸收测量扫描中确定了六个感兴趣区域（ROI）。对于每个ROI，确定了肢体之间的BMD相对差异（RD），并比较了两个时间点的RD。
结果：没有发现任何ROI的RD之间的差异。未报告修订或并发症。术后18个月，79.2％的队列对他们的手术结果非常满意或满意，牛津膝关节评分与术前相比显着改善（p<0.001）。平均膝关节运动范围为102°（SD10.7°），平均腿部对齐为2.0°外翻（1-6°外翻）。
结论：BMD分析结果表明，植入物固定良好，不影响功能。我们认为，对于不那么活跃的患者，使用APT和计算机导航是MBT的一个可行的更便宜的选择，具有较低的BMI和良好的骨骼质量。
方法：65岁以上的患者，BMI≤37.5kg/m2,且之前未进行关节置换,使用APT进行计算机导航全膝关节置换术.研究队列（n=27）的平均年龄为71.9（SD4.35），BMI为31.2（SD3.8）。术后6周和18个月进行BMD检查。在前/后和外侧双能量X射线吸收测量扫描中确定了六个感兴趣区域（ROI）。对于每个ROI，确定了肢体之间的BMD相对差异（RD），并比较了两个时间点的RD。
结果：没有发现任何ROI的RD之间的差异。未报告修订或并发症。术后18个月，79.2％的队列对他们的手术结果非常满意或满意，牛津膝关节评分与术前相比显着改善（p<0.001）。平均膝关节运动范围为102°（SD10.7°），平均腿部对齐为2.0°外翻（1-6°外翻）。
结论：BMD分析结果表明，植入物固定良好，不影响功能。我们认为，对于不那么活跃的患者，使用APT和计算机导航是MBT的一个可行的更便宜的选择，具有较低的BMI和良好的骨骼质量。
