Determination of optimal non-invasive patient fixation methods for use in robotic hip replacement surgery--an in vitro study.

BACKGROUND

A robotic system for the implantation of a total hip arthroplasty (THA) is currently under development. One of the goals of this system is non-invasive patient fixation, aiding the robotic system by an infrared tracking system. To determine the extent of fixation that can be achieved by non-invasive methods, an in vitro study was performed.

METHODS

In cadaver testing, different non-invasive fixation methods (Arthrex leg holder with tourniquet mechanism; arthroscopic leg holder with disposable foam inserts; gynaecological leg holder; Goepel knee crutch) were evaluated under load in different directions.

RESULTS

Deviation was measured in the range 0.33-18.1 mm with up to 20 N load. The testing showed the pneumatic leg holder system to provide the highest stability, followed by an arthroscopic leg holder system with foam inserts.

CONCLUSIONS

Use of a leg holder with foam inserts produced a stability that should enable tracking of the remaining deviation by the navigation system. We will therefore use this method in our future development of the robotic milling tool.