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Less resection of vital bone is necessary using hip surface replacement. This is one of the main reasons why these implants are indicated for younger patients. An exact positioning of the implant is crucial to avoid osseous complication and poor functionality. This is also essential for the instruments used.
This study evaluated the accuracy of a navigated implantation of a hip resurfacing implant using a fluoroscopic navigation system.
Ten cadaveric specimens in Thiel’s solution underwent a simulated navigated implantation of an ACCIS hip resurfacing prosthesis (Implantcast, Buxtehude, Germany). The fluoroscopic navigation system was developed by the Helmholtz-Institute for Biomechanical Engineering (RWTH Aachen University, Germany).
For implantation a posterior approach in lateral position of the specimen was used. After fixation of the “Dynamic Reference Base” on the proximal femur, the planning of the implant’s position was performed. After two x-ray images from different perspectives the planning can be carried out using the “Zero-dose-C-Arm” simulation.
The leading K-Wire was navigated while the femoral preparation and the implantation proceeded in conventional technique.
The mean time for navigation was 16,8 minutes.
After a CT-scan the proximal femur was analyzed. This showed a femoral notching in one case. The minimal distance between the pin of the prosthesis and the cortical bone was 3,96mm.
The mean distance error between planed and implanted position was 3,5mm. The mean angulation error was 2.38°.
The comparison with other publications shows the overall trend of fluoroscopic navigation being able to achieve a good positioning of the implant. The additional time effort represents the general average of fluoroscopic navigation.
This study can only suggest further analysis of this topic particularly in regard to a comparison with free-hand techniques and bone morphing.