Correct placement of the total elbow endoprosthesis is a critical factor for the long-term success of an artificial joint. Correct restoration of the centre of rotation is essential for optimal outcome. To evaluate whether surgical navigation has the potential to improve accuracy during Total Elbow Arthroplasty (TEA), an existing CAS system was applied on one plastic model and three patients.

The spine module of the SurgiGATE™ navigation system (Medivision, Oberdorf, Switzerland) was used. To apply it during TEA, a standard 3.5-mm drill guide was instrumented with infrared LEDs and calibrated. A dynamic reference base (DRB) was developed. Its base consisted of an X-shaped, scissors-like construct that could be clamped rigidly onto the distal humerus after exposure. On a plastic model, the DRB design was evaluated, and three landmarks suitable for intraoperative matching were identified. Subsequently, the Spine system was applied during three TEA surgeries. For the first surgery no pre-operative CT scan was acquired, but the design of the DRB, its camera visibility, and the accessibility of the landmarks were verified. For the other cases, the elbows were CT-scanned preoperatively. Planning consisted of 3-D segmentation as well as the definition of matching landmarks and a trajectory representing the position of a Steinmann pin, with which the humeral implant position is defined. Intraoperatively, the DRB was fixated, and matching was performed. Using the navigation system, the drill guide could then be aligned with the planned trajectory.

For the second patient, no accurate matching was achieved, hence surgery was completed conventionally. The last patient could be registered precisely, and the Steinmann pin was placed as planned.

Preliminary results show that CT-based navigation can be applied during TEA. Given a positive output of an ongoing clinical study, the development of a special TEA navigation system is planned.