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High stiffness fracture fixation devices inducing absolute stability, activate inefficient primary healing and stress shielding. Taking High Tibial Osteotomy as a representative example, review of the clinical literature and mapping the fracture healing process revealed two physically contradicting requirements, which are only partially met by current techniques. Stiffness of the fixation is required immediately after fracture, however in the remodelling phase this can cause stress shielding. Stability is required immediately after fracture, however in the ossification phase less stability is required to stimulate secondary (and more efficient) healing. This study evaluates the use of the TRIZ Inventive Design Principles to overcome these physical contradictions. Six designs concepts were evaluated, of which the Macro-Geometry stiffness modulated design was ranked the highest. This was achieved through spatial decomposition of the problem utilising the Inventive Principles of Asymmetry, Extraction and Local Quality. This study offer perspectives on how to increase the patient specificity of fixation utilising the increased topology freedom of design for additive manufacture (AM).

Additive manufacturing (AM) offers a number of benefits over conventional manufacturing, giving an increased design freedom and the opportunity to integrate multiple components, saving weight. The rigorous standard for material integrity set by the Aerospace sector necessitates the development of systems to ensure quality. Laser ultrasonic testing (LU) is a non-contact inspection technique which has been proposed as suitable for in-situ monitoring of additive manufacturing processes, as measurements can be taken at elevated temperatures. This paper will show the capability of this technique for assuring material quality in metal AM parts and compare LU with x-ray computed tomography (XCT).

This paper describes the use of a non-contact structured light scanning technique, computer aided design (CAD) and additive manufacturing (AM) to produce a burns pressure therapy splint, also known as mask or conformer. Masks such as this are used in the treatment of hypertrophic scars resulting from burns injuries. The case study described here is of a nine year old girl with significant hypertrophic scars to her face, especially her nasal bridge. Non-contact structured light scanning was used to capture accurate data of the patients face. This data was then post processed and used to produce a model of the patients face using the three dimensional printing processes from Z Corporation. The plaster model formed was then used to generate a former on which a polyethylene tetrephthalate glycol (PETG) mask was vacuum formed. The results illustrate the benefits and effectiveness in terms of accuracy of adopting an integrated surface scanning, CAD and AM approach for easier intervention and treatment.

One approach to developing a mathematical model that predicts osteoactivity both in bio-scaffolds, as well as the in bone tissue in vivo, is based on a bio-cybernetic vision of basic multicellular unit (BMU) action. In the case of the model presented in this paper, some of the loops of regulation have been modified to reflect the range of allosteric control mechanisms: Michaelis–Menten, Hill, Adair, Koshland–Nemethy–Filmer (KNF), Monod–Wyman–Changeux (MWC). This approach has resulted in a four-dimensional system that shows steady cyclic behaviour using a range of constants with clear biological meaning. The initial findings suggesting that a steady state appears as a cycle in multidimensional phase space and this is discussed in this paper. The existence of this cycle in the osteoclasts–osteoblasts–osteocytes–bone subspace indicates that there is a conservative value along steady trajectories for this dynamic system. Biophysical interpretation of this conservative value has been proposed as a kind of substrate-energy regenerative potential of the bone remodelling system with a similarity to the classical physical value—energy. Such a recovery “potential” is directed against both mechanical and biomechanical damage to the bone. The current model has credibility when compared to the normal bone remodelling process. In the framework of widely recognised Michaelis–Menten mechanisms of allosteric regulation the cyclic attractor, described formerly for a pure cellular model, prevails for different forms of feedback control. This finding demonstrates the viability of the suggestion of the subsistence of conservative value (analogous to energy) that characterises the recovery potential of the bone remodelling cycle. The results indicate that the robust behaviour of the model is maintained from the simple cellular level to the molecular biochemical level of regulation.

Biological parameters, such as bone resorption and formation constants, are important variables to achieve optimised hard tissue scaffolds design. To help to understand the modelling process that occurs when a scaffold is implanted it is vital to understand the rather complex bone remodeling process prevalent in native bone. One approach to developing a mathematical model that predicts osteoactivity both in scaffolds, as well as in bone in vivo, is based on a bio-cybernetic vision of basic multicellular unit (BMU) action – Komarova et al. (2003) . In the case of the model presented in this paper, an additional loop of regulation based on osteocyte activity has been added. This approach has resulted in a four-dimensional system, which shows steady-quasi-cyclic behaviour using a particular range of constants with real biological meaning. The initial findings suggesting that the basic steady-state appears as a torus in multidimensional phase space have been discussed. The existence of this surface in the osteoclasts–osteoblasts-osteocytes-bone subspace indicates that there is a first integral for this dynamic system. Biological and physical interpretation of this integral as a conservative value has been proposed. It is possible to draw an analogy between this conservative value, as a kind of substrate–energy regenerative potential of the bone remodeling system with a molecular nature, to the classical physical value (energy). There are clear indications that there is recovering potential within the BMU that results in a steady operating genetically predominated bone remodeling process. This recovering potential is directed against both mechanical and biomechanical damage to the bone. The current model has credibility when compared to the normal bone remodeling process. However, additional work is required to study a wider range of constants.