Robotic total knee arthroplasty: the accuracy of CT-based component placement

Acta Orthop Scand. 2004 Oct;75(5):573-9. doi: 10.1080/00016470410001448.


Background: Accurate alignment of the components in total knee arthroplasty is important. By use of postoperative CT controls, we studied the ability of a robotic effector to accurately place and align total knee arthroplasty (TKA) components according to a purely CT-based preoperative plan.

Patients and methods: Robotic TKA was performed in 13 patients (6 men) with primary gonarthrosis. Locator screws were placed into femur and tibia under spinal anesthesia. A CT-scan including the femoral head, knee and ankle was performed. In the preoperative planning software, virtual components were positioned into the CT volume. In a second operation, the robot milled femur and tibia with a high-speed milling tool according to the preoperative plan. On the 10th day, CT controls were performed following the same protocol as preoperatively.

Results: The mean deviation of the postoperative from the preoperatively planned mechanical axis was 0.2 degrees (95% CI: -0.1 degrees to 0.5 degrees ). The accuracy of angular component placement in frontal, sagittal and transverse planes was within +/-1.2 degrees , and the accuracy of linear component placement in mediolateral, dorsoventral and caudocranial directions was within +/-1.1 mm.

Interpretation: Robotic TKA allows placement of components with unparalleled accuracy, but further development is mandatory to integrate soft-tissue balancing into the procedure and make it faster, easier and cheaper.

MeSH terms

  • Arthritis / surgery
  • Arthroplasty, Replacement, Knee / methods*
  • Humans
  • Leg / diagnostic imaging
  • Postoperative Period
  • Preoperative Care
  • Robotics*
  • Tomography, X-Ray Computed*