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The purpose of this paper is to examine the use of fused deposition modelling (FDM) models and finite element analysis (FEA) related to dysplastic hip orthopaedic surgery.

The study involved the use of Mimics and Abaqus softwares. Mimics was used to process the CT scan patient data to STL format before producing FDM models which were for before and after surgery. FEA was done to study the two different type of implant biomaterials used in dysplastic hip surgery.

The use of FDM pre models for preplanning of dysplastic hip surgery by orthopaedic surgeons and viewing of the surgery outcome via FDM post models. Different implant biomaterials used gave different results in reduction of stresses that were achieved.

This is original work involving patients in hospital, which got ethical approval and was funded by a university grant. The paper describes a new kind of research in the university.

The purpose of this paper is to present an improved methodology for design of custom‐made hip prostheses, through integration of advanced image processing, computer aided design (CAD) and additive manufacturing (AM) technologies.

The proposed methodology for design of custom‐made hip prostheses is based on an independent design criterion for each of the intra‐medullary and extra‐medullary portions of the prosthesis. The intra‐medullar part of the prosthesis is designed using a more accurate and detailed description of the 3D geometry of the femoral intra‐medullary cavity, including the septum calcar ridge, so that an improved fill and fit performance is achieved. The extra‐medullary portion of the prosthesis is designed based on the anatomical features of the femoral neck, in order to restore the original biomechanical characteristics of the hip joint. The whole design procedure is implemented in a systematic framework to provide a fast, repeatable and non‐subjective response which can be further evaluated and modified in a preplanning simulation environment.

The efficacy of the proposed methodology for design of custom‐made hip prostheses was evaluated in a case study on a hip dysplasia patient. The cortical bone was distinguished from cancellous in CT images using a thresholding procedure. In particular the septum calcar ridge could be recognized and was incorporated in the design to improve the primary stability of the prosthesis. The lateral and frontal views of the prosthesis, with the patient's images at the background, indicated a close geometrical match with the cortical bone of femoral shaft, and a good compatibility with the anatomy of the proximal femur. Also examination of the cross sections of the prosthesis and the patient's intra‐medullary canal at five critical levels revealed close geometrical match in distal stem but less conformity in proximal areas due to preserving the septum calcar ridge. The detailed analysis of the fitting deviation between the prosthesis and point cloud data of the patient's femoral intra‐medullary canal, indicated a rest fitting deviation of 0.04 to 0.11 mm in stem. However, relatively large areas of interference fit of −0.04 mm were also found which are considered to be safe and not contributing to the formation of bone cracks. The geometrical analysis of the extra‐medullary portion of the prosthesis indicated an anteversion angle of 12.5 degrees and a neck‐shaft angle of 131, which are both in the acceptable range. Finally, a time and cost effective investment casting technique, based on AM technology, was used for fabrication of the prosthesis.

The proposed design methodology helps to improve the fixation stability of the custom made total hip prostheses and restore the original biomechanical characteristics of the joint. The fabrication procedure, based on AM technology, enables the production of the customized hip prosthesis more accurately, quickly and economically.

This paper aims to focus on the changes in thermal and surface characteristics of acrylonitrile butadiene styrene (ABS) material when exposed to chemical vapours for surface finishing. The poor surface finish and the dimensional accuracy of the fused deposition modelling parts (of ABS material) because of the stair-stepping hinder their use for rapid tooling applications, which can be improved by vapour finishing process. The differential scanning calorimetry (DSC) tests are performed to investigate the thermal behaviour of ABS thermoplastic after vapour finishing.

The hip prosthesis replica has been used to highlight the efficacy of chemical finishing process for intricate and complex geometries. The replicas are treated with chemical vapours for different durations. The DSC tests are performed along with surface roughness, surface hardness and dimensional measurements of exposed replicas and compared with unexposed replica.

The longer finishing time, i.e. 20 s, manifested higher melting peak temperature, higher melting enthalpy and higher heat capacity along with smoother and harder surface as compared with unexposed replica. The finishing process enhanced the bonding strength and the heat-bearing capacity of ABS material. The vapour finishing process enhanced the thermal stability of the material which may extend its sustainability at higher temperatures.

The improved thermal stability of ABS thermoplastic after chemical vapour finishing has been demonstrated. This advancement allows the use of ABS in functional tooling suitable for small production runs with higher flexibility and lead time savings.

The heat effects associated with phase transitions as a function of temperature are studied in case of replicas finished with chemical vapours. The relationship between melting enthalpy and surface characteristics has been ascertained.

This study aims to provide an overview of rapid prototyping (RP) and shows the potential of this technology in the field of medicine as reported in various journals and proceedings. This review article also reports three case studies from open literature where RP and associated technology have been successfully implemented in the medical field.

Key publications from the past two decades have been reviewed.

This study concludes that use of RP-built medical model facilitates the three-dimensional visualization of anatomical part, improves the quality of preoperative planning and assists in the selection of optimal surgical approach and prosthetic implants. Additionally, this technology makes the previously manual operations much faster, accurate and cheaper. The outcome based on literature review and three case studies strongly suggests that RP technology might become part of a standard protocol in the medical sector in the near future.

The article is beneficial to study the influence of RP and associated technology in the field of medicine.