Navigation systems have been introduced to find accurate alignment during the total hip replacement surgery. In these navigation system operator obtains the 3D image of the patient’s bone by the CT scan before the operation. Then during the operation navigation system gives the information about the proper position of implant, by using pin-based registration or image-based registration. Both registration method use 3D image of the bone to know the position and the orientation of the implants during the operation. But these systems require CT scan, which results in extra cost and additional radiation exposure for the patient. So, I suggest a CT free registration method.
The CT proposed free registration is based on anatomical landmark of the pelvic. These landmark points are the anterior superior iliac spines and the symphysis pubis. Anterior pelvic plane defined by these points is standard for measuring the orientation angle of acetabular cup. The CT free registration is performed by directly measuring these points on the skin of patient’s pelvic during the operation without 3D image of bone. Conventional 3D measurement device and custom-made T-gauge was used to develop the system. Operator could simply obtain the information of the implant’s alignment by this registration method. The developed system was tested and evaluated by human model.
In this paper deals with a CT free registration for an acetabular-cup navigation system. The CT free registration provides position and alignment information without additional cost and radiation exposure. Moreover the experimental results show that this method is available in clinical practice.
