A novel rapid prototyping and finite element method-based development of the patient-specific temporomandibular joint implant.

OBJECTIVE: The objective of this study was to fabricate a successful implant for temporomandibular joint (TMJ) disorder patients who could not be treated through conventional surgeries. METHODS: A custom-made implant was fabricated using rapid prototyping (RP) for the TMJ surgery. The stability of the metallic implant was validated using a finite element analysis. RESULTS: The results of finite elements were stable and the design of the TMJ implant was suitable as per the patient's need. The customised implant was made using a fused deposition modelling method of RP and a vertical machining centre. The implant has provided normal jaw function for over 2 years since surgery. CONCLUSIONS: The approach utilised will be helpful in providing successful treatment to the deformed mandible and the mandible joints. This method allows to customise and to accurately fabricatie the implant. Advantages of this approach are that the physical model of the implant was tested for stability before the implantation, the surgeon can plan and rehearse the surgery in advance, it is a less invasive and less time-consuming surgical procedure.

Design and manufacturing of customised femoral stems for the Indian population using rapid manufacturing: a finite element approach.

Joint replacement surgeries in India primarily involve the use of conventional implants, also referred to as 'standard implants'. There has been a little awareness about the possibility of using customised implants for such surgeries. Although standard implants from various biomedical companies are easily available in the Indian market, they are expensive and rarely conform to patient's anatomy. Studies in the past have shown that there are anatomical variations in the hip joint for different ethnic backgrounds and geographical locations. This article evaluates the feasibility of using custom-manufactured hip implants and presents a comparison between the former and standard implant from stress reduction point of view. Two CAD models of femoral stems - one from standard sized hip implant available in the market and other from customised hip implant designed as per parameters from a radiograph (specific to the patient's anatomy) - are used for evaluation. Finite element analysis was carried out for a double-legged stance. The comparative study indicated lesser stresses in head and neck region of the customised femoral stems than the standard implant. The study suggests design feasibility of customised implants for the Indian population owing to reduction in stresses in the implant.

Preplanning and simulation of surgery using rapid modelling.

Rapid prototyping (RP) is increasingly being used for solution of many problems associated with biomedical engineering. RP quickly delivers prototypes that are constructed in an additive, layer-by-layer process driven by three-dimensional computer aided design (CAD) data. The aim of this work was to demonstrate that surgery for acetabulum fracture can be significantly facilitated through the use of a method based on advanced imaging techniques and the RP technique. A case of complex acetabulum fracture was reported, and application of computed tomography (CT) images, CAD and RP were explored. Modelling of the fractured part helped in preplanning and simulating the surgery and saved surgery time. The method allowed feedback action at most steps of the surgery process, thus permitting an important time saving during surgery.