Tjørnild Michael, Søballe Kjeld, Hansen Per Møller, Holm Carsten, Stilling Maiken
Department of Orthopedics, Horsens Regional Hospital, Horsens.
Acta Orthop. 2015 Apr;86(2):208-14. doi: 10.3109/17453674.2014.968476. Epub 2014 Oct 3.
It is unclear whether mobile-bearing (MB) total knee arthroplasties reduce the risk of tibial component loosening compared to fixed-bearing (FB) designs. This randomized study investigated implant migration, periprosthetic bone mineral density (BMD), and patient-reported outcomes (Oxford knee score)-all at 2 years-for the P.F.C. Sigma Cruciate Retaining total knee arthroplasty.
50 osteoarthritis patients were allocated to either FB or MB tibial articulation.
At 2 years, the mean total translation (implant migration) was higher for the FB implant (0.30 mm, SD 0.22) than for the MB implant (0.17 mm, SD 0.09) (p = 0.04). BMD decreased between baseline and 1-year follow-up. At 2-year follow-up, BMD was close to the baseline level. The knee scores of both groups improved equally well. The FB tibial implant migrated more than the MB, but this was not clinically significant. The mobile polyethylene presumably partly absorbs the force transmitted to the metal tibial tray, thereby reducing micromotion.
与固定平台（FB）设计相比，活动平台（MB）全膝关节置换术是否能降低胫骨组件松动的风险尚不清楚。这项随机研究在2年时调查了P.F.C. Sigma交叉韧带保留型全膝关节置换术的植入物移位、假体周围骨密度（BMD）以及患者报告的结局（牛津膝关节评分）。
50例骨关节炎患者被分配至FB或MB胫骨关节置换组。
在2年时，FB植入物的平均总移位（植入物迁移）（0.30毫米，标准差0.22）高于MB植入物（0.17毫米，标准差0.09）（p = 0.04）。骨密度在基线和1年随访之间下降。在2年随访时，骨密度接近基线水平。两组的膝关节评分改善程度相同。FB胫骨植入物的移位比MB更多，但这在临床上并不显著。活动聚乙烯大概部分吸收了传递到金属胫骨托的力，从而减少了微动。
