Title : How to create a patient-specific overformed implant for bone reconstruction
Abstract:
There are some challenging situations for bone reconstruction in humans. Implants are very beneficial for reconstruction. They are created anatomically the same as the patient’s bone. Patellar luxation is one of them. Mostly seen complications are cartilage damage and pain. This study presents a new patient-specific method of overformed implant design method whose shape is different from normal anatomical shape. The implant prevents luxation of the patella without damaging the cartilage.
Design processes are Computer Tomography, Computer Assisted Design, rapid prototyping of the bone replica, creation of the implant with the surgeon’s haptic knowledge on the bone replica, 3D printing of the implant and clinical application. The focus of the method is the haptic design of the implant according to the surgeon’s knowledge and experience. The implant is created with the surgeon’s hand using a self-hardening paste. It is created on the bone replica of the patient. The surgeon determines how far to go beyond the normal anatomical limits.
The implant was fully seated on the bone. Patella reluxation or implant-related bone problem was not observed 80 days after the operation. Three-point bending test and finite element analysis were performed to determine the biomechanical safety of the implant. The stress acting on the implant was below the biomechanical limits of the implant. More cases with long-term follow-up are needed to confirm the success of this method in patellar luxation. Compared with trochlear sulcoplasty and total knee replacement, there was no cartilage damage done by surgeons with this method, and the implant keeps the patella functionally in the sulcus.
This is a promising multidisciplinary method that can be applied to any part of the bone such as vertebra and maxillofacial bones. This method can solve some orthopaedic problems with the surgeon’s haptic knowledge.
