Robot vs. Manual UKA

September 21, 2014 Haw Chong Chang

Accuracy of Component Implantation

What You Plan is What You Get

  • Pearle in his series of 10 cases of robot-assisted UKA concluded that the difference between planned and intraoperative tibiofemoral angle was within 1° and the postoperative long leg axis radiographs were within 1.6°.

–Pearle AD, O’Loughlin PF, Kendoff DO. Robot-assisted unicompartmental knee arthroplasty. J Arthroplasty. 2010 Feb;25(2):230–7.

Robot vs. Manual UKA

  • Lonner compared the postoperative radiographic alignment of the tibial component with the preoperatively planned position in 31 knees in 31 consecutive patients undergoing UKA using robotic arm-assisted bone preparation and in 27 consecutive patients who underwent unilateral UKA using conventional manual instrumentation to determine the error of bone preparation and variance with each technique.
  • Radiographically, the root mean square error of the posterior tibial slope was 3.1° when using manual techniques compared with 1.9° when using robotic arm assistance for bone preparation.
  • The variance using manual instruments was 2.6 times greater than the robotically guided procedures.
  • In the coronal plane, the average error was 2.7 ± 2.1 more varus of the tibial component relative to the mechanical axis of the tibia using manual instruments compared with 0.2 ± 1.8 with robotic technology.

–Lonner JH, John TK, Conditt MA. Robotic arm-assisted UKA improves tibial component alignment: A pilot study. Clin Orthop Relat Res. 2010 Jan;468(1):141–6.


Robot vs. Manual UKA

  • Coon compared 35 robotic cases with 45 conventional ones and found the accuracy of the:
    • Tibial implant slope to be 2.5 times better (p < 0.05),
    • Varus alignment to be 3.2° better (p < 0.05) .
    • SD to be 2.8 times less (p < 0.05) in the robotic arm group.

– Thomas N Coon. Integrating robotic technology in the operating room Am J Orthop. 2009 Feb;38(2 suppl):7–9.