Department of Orthopedic Surgery, University of California, San Diego, San Diego, California.
Hoag Orthopedic Institute, Irvine, California.
J Arthroplasty. 2018 Jan;33(1):61-66. doi: 10.1016/j.arth.2017.06.004. Epub 2017 Jun 9.
Recent advances in total knee arthroplasty (TKA) include an intelligent instrument system designed to provide intraoperative guidance to reduce mechanical alignment errors. Internal position-sensing technology is integrated into microelectronic pods that attach to cutting blocks. The purpose of this prospective, randomized study was to determine whether this iAssist system enables the surgeon to make more accurate bone resections and better restore the mechanical axis compared to conventional instruments in TKA.
We randomized patients undergoing TKA into 2 groups. Group I (n = 25) underwent TKA assisted by the iAssist guidance system, group II (n = 25) underwent TKA using conventional instruments. Preoperative and postoperative mechanical axes were measured from full-length lower extremity radiographs to evaluate alignment. Additional surgical parameters were also assessed, including tourniquet time and blood loss.
Patient demographics and preoperative mechanical axis alignments were similar between the groups. Postoperatively, 4.0% of patients had greater than 3° of tibial or femoral component mal-alignment in the guidance-assisted cohort, compared with 36.0% in the conventional group (P < .05). Additionally, group I showed significant improvement in variance seen in both the femoral mechanical axis (1.65° ± 0.17° vs 2.23° ± 0.33°, P < .005) and tibial mechanical axis (1.28° ± 0.13° vs 1.71° ± 0.24°, P < .005) compared to group II. There were no significant differences in tourniquet time (P = .86) or blood loss (P = .39) between groups.
Use of the iAssist system in TKA results in an improved postoperative mechanical axis and decreased alignment variability compared to conventional instruments, without significantly increasing operative time.
全膝关节置换术（TKA）的最新进展包括一种智能仪器系统，旨在提供术中指导以减少机械对线误差。内部位置感应技术集成到微电子豆荚中，这些豆荚附着在切割块上。本前瞻性、随机研究的目的是确定与传统器械相比，iAssist 系统是否能使外科医生在 TKA 中进行更精确的骨切除并更好地恢复机械轴。
我们将接受 TKA 的患者随机分为 2 组。组 I（n=25）接受 iAssist 引导系统辅助的 TKA，组 II（n=25）接受传统器械的 TKA。从全长下肢 X 线片测量术前和术后机械轴，以评估对线情况。还评估了其他手术参数，包括止血带时间和失血量。
两组患者的人口统计学和术前机械轴对线情况相似。术后，在引导辅助组中有 4.0%的患者胫骨或股骨组件对线不良大于 3°，而在传统组中有 36.0%（P<.05）。此外，组 I 在股骨机械轴（1.65°±0.17°比 2.23°±0.33°，P<.005）和胫骨机械轴（1.28°±0.13°比 1.71°±0.24°，P<.005）的方差方面显示出显著改善，与组 II 相比。两组间止血带时间（P=.86）或失血量（P=.39）无显著差异。
与传统器械相比，在 TKA 中使用 iAssist 系统可改善术后机械轴，减少对线变化，而不会显著增加手术时间。
