Introduction: Resurfacing arthroplasty represents an alternative method to total hip replacement especially for the young and active patient. The main reasons for early implant failure are mal-positioning of the femoral component and notching of the femoral neck during femoral head preparation.
Material and methods: In the context of a cadaver study of formalin-fixed cadaveric full body specimens 6 DUROM -Hip-Resurfacing prosthesis have been implanted under navigation control. The aim of the study was an evaluation of the functionality and accuracy of the computer-assisted planning and navigation system on the basis of a navigation module library from Surgitaix AG Aachen, Germany.
Results: The main angulation error between planning (135.2 +/- 3.6 degrees ) and navigation (136.2 +/- 2.8 degrees ) was 1.9 +/- 1.1 degrees , the main anterior offset error between planning (2.2 +/- 1.3 mm) and navigation (2.7 +/- 2.3 mm) was 1.2 +/- 1.9 mm. The main distance error between planning and navigation was 2.7 +/- 1.3 mm. The mean time for all five planning and navigation steps was 20.2 +/- 2.5 min. Against the background of a acetabular bone-saving approach in all 6 cases the smallest possible femoral component could be implanted.
Conclusion: The computer-assisted fluoroscopic planning and navigation system for hip resurfacing showed within the scope of this cadaver study first promising results. The system approaches a practicable intraoperative planning with a high accuracy in operative implementation. Nevertheless, the potential benefit has to be evaluated in further clinical studies, especially from the perspective of a possible integration of this navigation system into the clinical work-flow. Further studies should consider a fluoroscopic-assisted range of motion assessment under consideration of an additional cup-module to enhance the postoperative range of motion after hip resurfacing procedures.