Athens Orthopedic Clinic, PA, 1765 Old West Broad Street, Building 2, Suite 200, Athens, GA 30606, USA.
Clin Orthop Relat Res. 2012 Jan;470(1):33-44. doi: 10.1007/s11999-011-2114-5.
Mobile bearing (MB) total knee design has been advocated as a means to enhance the functional characteristics and decrease the wear rates of condylar total knee arthroplasty (TKA). However, it is unclear if these designs achieve these goals.
QUESTIONS/PURPOSES: We asked whether function of patients or survivorship would be greater or complications would be lesser in groups of patients with MB compared with fixed bearing (FB) TKA. We also sought to describe retrieval findings.
We randomized 507 primary TKAs in 416 eligible patients to receive MB (n = 252) or FB (n = 255) devices from November 2001 to August 2007 (Investigational Device Exemption G000180, ClinicalTrials.gov registration number NCT00946075). Patients were blinded to treatment allocation. WOMAC Index, SF-12 Health Survey, knee range of motion, and Knee Society scores were collected and compared preoperatively and at 6, 12, and 24 months postoperatively. We recorded device failures and complications until October 2009. Kaplan-Meier survivorship was compared using the log rank test. Twelve retrieved MB devices underwent pathologic analysis. The minimum postoperative time was 2.2 years (mean, 5.9 years; range, 2.2-7.9 years).
We found no differences in mean clinical assessment scores or mean score changes from baseline at any postoperative interval through 2 postoperative years. Nineteen of the 252 MB and 13 of the 255 FB knees had undergone revision of any component. Estimated survival at 6 postoperative years was similar for the two devices: 90.1% (95% confidence interval [CI], 84.1-93.9) for MB and 94.2% (95% CI, 90.1-96.6) for FB. Two MB and no FB tibial components were revised for loosening. There was one case of MB insert dislocation. Retrieved MB devices demonstrated no unexpected wear or mechanical device failures.
We found no evidence of functional advantage of the MB design. Survivorship was similar, although the study is limited by short duration of followup.
为了增强膝关节置换术的功能特性和降低髁状面磨损率，倡导使用活动衬垫（MB）全膝关节设计。 但是，目前尚不清楚这些设计是否能达到这些目标。
问题/目的： 我们比较了 MB 与固定衬垫（FB）TKA 组患者的功能或生存率更高，并发症更少。 我们还试图描述了回收发现。
我们在 2001 年 11 月至 2007 年 8 月期间，将 416 名符合条件的患者中的 507 例初次膝关节置换术随机分为 MB（n = 252）或 FB（n = 255）组。 患者对治疗分配不知情。 在术前和术后 6、12 和 24 个月收集了 WOMAC 指数，SF-12 健康调查，膝关节活动范围和膝关节协会评分，并进行了比较。 我们记录了设备故障和并发症，直到 2009 年 10 月。使用对数秩检验比较 Kaplan-Meier 生存率。 对 12 个回收的 MB 设备进行了病理分析。 最短的术后时间为 2.2 年（平均 5.9 年；范围为 2.2-7.9 年）。
在术后 2 年的任何术后间隔，我们均未发现平均临床评估评分或从基线平均评分变化的差异。 在 252 例 MB 中有 19 例和 255 例 FB 中有 13 例进行了任何组件的翻修。 两种设备在术后 6 年的估计生存率相似：MB 为 90.1％（95％置信区间[CI]，84.1-93.9），FB 为 94.2％（95％CI，90.1-96.6）。 两个 MB 和一个 FB 胫骨组件因松动而进行了翻修。 有一个 MB 插入物脱位的病例。 回收的 MB 设备未显示出任何异常磨损或机械装置故障。
我们没有发现 MB 设计具有功能优势的证据。 生存率相似，尽管该研究受随访时间短的限制。
