Colorado Joint Replacement, 2535 S Downing Street, Number 100, Denver, 80210 CO, USA.
Clin Orthop Relat Res. 2012 Jan;470(1):150-8. doi: 10.1007/s11999-011-2099-0.
High-flexion TKA prostheses are designed to improve flexion and clinical outcomes. Increased knee flexion can increase implant loads and fixation stresses, creating concerns of premature failure. Whether these goals can be achieved without premature failures is unclear.
QUESTIONS/PURPOSES: We assessed pain relief, knee motion, function, incidence of premature failure, and radiographic appearance in patients with a mobile-bearing high-flexion TKA and determined whether preoperative knee flexion affects postoperative knee flexion.
We prospectively followed all 142 patients implanted with 154 mobile-bearing high-flexion TKAs between 2004 and 2007. We obtained Knee Society scores (KSS) and assessed radiographs for loosening. Minimum followup was 24 months (mean, 46 months; range, 24-79 months).
Average knee flexion improved from 123° to 129°. Patients with preoperative flexion of 100° to 120° had a greater postoperative flexion increase (mean, 13°; range, 114°-126°) than patients with preoperative flexion of greater than 120° (mean, 3.0°; range, 128°-131°). The mean KSS improved from 41 to 95 postoperatively. Patients with preoperative flexion of less than 120° had a greater improvement in KSS (62 versus 48). Posterior femoral radiolucent lines were observed in 43% without evidence of prosthetic loosening.
Our data were similar to those reported in patients implanted with traditional and other designs of high-flexion TKA. We found no increased incidence of premature failure, although a higher than expected incidence of posterior femoral radiolucent lines merit continued observation. Patients with less preoperative motion were more likely to benefit from a high-flexion TKA.
高屈曲度膝关节假体的设计旨在改善膝关节的屈曲度和临床效果。增加膝关节的屈曲度会增加植入物的负荷和固定应力，从而产生提前失效的担忧。但目前尚不清楚这些目标能否在不提前失效的情况下实现。
问题/目的：我们评估了患有活动平台高屈曲度膝关节置换术的患者的疼痛缓解、膝关节活动度、功能、提前失效的发生率和影像学表现，并确定术前膝关节的屈曲度是否会影响术后膝关节的屈曲度。
我们前瞻性地随访了 2004 年至 2007 年间植入 154 例活动平台高屈曲度膝关节假体的 142 例患者。我们获得了膝关节协会评分（KSS）并评估了松动的影像学表现。随访时间至少为 24 个月（平均 46 个月；范围 24-79 个月）。
平均膝关节屈曲度从 123°增加到 129°。术前屈曲度为 100°至 120°的患者术后膝关节屈曲度增加幅度更大（平均 13°；范围 114°-126°），而术前屈曲度大于 120°的患者增加幅度较小（平均 3.0°；范围 128°-131°）。术后 KSS 平均从 41 分提高到 95 分。术前屈曲度小于 120°的患者 KSS 改善更大（62 分比 48 分）。43%的患者出现了后股骨放射性透亮线，但没有假体松动的证据。
我们的数据与植入传统和其他高屈曲度膝关节假体的患者的数据相似。我们没有发现提前失效的发生率增加，尽管后股骨放射性透亮线的发生率高于预期，需要继续观察。术前活动度较小的患者更有可能从高屈曲度膝关节置换术中获益。
