Single Use Instruments for Implanting a Contemporary Total Knee Arthroplasty System Are Accurate, Efficient, and Safe

J Arthroplasty. 2021 Jan;36(1):135-139.e2. doi: 10.1016/j.arth.2020.07.025. Epub 2020 Jul 21.


Background: Single use instruments (SUI) is a potential mechanism to improve efficiency and reduce cost in total knee arthroplasty (TKA). New technology requires patient safety and surgical accuracy. A multi-center study of SUI vs reusable mechanical instrumentation (RUI) for a TKA system compared implant placement accuracy and operating room (OR) efficiency.

Methods: Four surgeons implanted 88 primary TKAs, N = 44 RUI and N = 44 SUI. Accuracy was measured radiographically at 3 months. The primary endpoint was non-inferiority of absolute value of mechanical axis alignment. Radiographic endpoints, OR times, and adverse events were also evaluated.

Results: Seventy-five subjects completed the study (41 SUI/34 RUI). The primary endpoint non-inferiority of SUI vs RUI was met, with no significant difference between SUI and RUI in most radiographic parameters (distal femoral varus-valgus, proximal tibial varus-valgus, tibial slope, or subjects within 3° of target); there was a slight difference in femoral component flexion angle (P = .015). SUI and RUI mean (SD) OR set-up times were 18.8 (10.03) and 26.7 (6.93) (P <.001), and surgical times (first incision to last stitch) were 64.6 (16.95) and 60.5 (19.01) (P = .295), respectively. Differences in OR clean-down and anesthesia were not significant. There were no revisions, and there was no significant difference in the number of reported adverse events.

Conclusion: SUI resulted in similar accuracy of implant placement to RUI with decreased OR set-up time and no increase in adverse events. These results support the safety and efficacy of SUI for performing TKA. Further analysis of potential economic and technical advantages is warranted.

Keywords: OR efficiency; radiographic outcomes; single use instruments; surgical instruments; total knee arthroplasty.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arthroplasty, Replacement, Knee* / adverse effects
  • Biomechanical Phenomena
  • Humans
  • Knee Joint / diagnostic imaging
  • Knee Joint / surgery
  • Range of Motion, Articular
  • Tibia / surgery