Accuracy of a freehand sculpting tool for unicondylar knee replacement

Abstract

BACKGROUND: Unicondylar knee replacement is technically challenging and malalignment of the implant components is one of the factors that results in high failure rates. Surgical robotics with navigation is emerging as a potential solution to improve the accuracy of implant placement. METHODS: The accuracy of performing unicondylar knee replacement using a freehand sculpting, semi-active robotic tool was investigated using 20 synthetic femurs and tibia. Resultant femoral and tibial implant placement was compared to the planned implant position. RESULTS: The maximum rotational error was 3.2(o) and RMS angular error was 1.46(o) across all orientations, for both the tibia and femoral implants. The maximum translational error was 1.18 mm and the RMS translational error across all directions was 0.61 mm. CONCLUSIONS: The freehand sculpting tool produced accurate implant placement with small errors comparable to those reported by other robotic-assistive devices on the market for unicondylar knee replacement.