# Design of a Modular Plantar Orthosis System through the Application of TRIZ Methodology Tools
## 4 Discussion
Finally, productivity refers to both production and cost per unit time, and standardization is intended to increase the productive capacity per unit time of orthotic systems. Out of the 21 inventive principles that the matrix proposes, only four apply: segmentation, inversion, transition to a new dimension, and porous materials. The selection of these is based on the prioritization of manufacturability as a parameter to be safeguarded, because it allows the optimization of costs. The inventive principle called segmentation sections the system into independent parts, from here, it derives the fact that the system is made up by four subsystems, with one of them being the central subsystem, and the other three being movable. The latter arise from the inversion principle, since the supports that are commonly fixed in other plantar orthoses present mobility here. The bolt-hole assembly mechanism is based on the inventive principles called transition to a new dimension and porous materials. All the subsystems have a plurality of small holes so that within these, the subsystems can be coupled to each other by means of a series of bolts integrated in one of their sides. Likewise, the coupling can occur on both sides of certain areas of the plantar base. Regarding the characteristics of each subsystem, the plantar base was designed according to the \(\frac{3}{4}\) length type with the intention that the system can be accommodated in the majority of the footwear, given that the biggest challenge of the clinical professionals is not always the prescription of the orthosis, but the adaptation of this orthosis to the patient's preference of footwear [6]. For this reason, the plantar base can be manufactured in different dimensions in relation to its length and width, as long as its longitudinal termination is maintained up to the metatarsal heads. Regarding the longitudinal arch, it can be manufactured in different heights so that the clinical professional has options regarding the incorporation of this subsystem for the treatment of both supination and desecration of the foot. On the other hand, the metatarsal button subsystem can be incorporated to the plantar base or not. This will depend on the clinician's evaluation regarding the load on the metatarsal region of the foot. Finally, the rearfoot wedge has the quality to be incorporated either by the lateral or medial part of the heel area of the plantar base. The length of the bolts protruding from the longitudinal arch, metatarsal button, and hindfoot wedge are the same dimension as the depth of the holes in the plantar base, so the bolts do not protrude from it or cause discomfort. Currently, there are system designs introduced in the footwear industry that have similarity with the proposed design because they have characteristics of adjustability and modularity. For example, the patent application publication US20110302805A1 [33] shows a system that can be fitted inside a shoe and includes a set of arch supports; each arch belonging to the set of supports is made with a different density to provide various levels of hardness and stability to the arch of the foot. This system is different from the one we propose since the arches of the present work have the possibility of moving in a longitudinal way with greater amplitude, so that the position of the arch can be in a more precise way with respect to the greater vertex of the arch of the user's foot, in addition with having a bolt-hole mechanism of the arch with the base. Patent US77/0309B2 [34] features a removable shoe insert with a groove on its medial edge extending below the arch. Another insert is placed in the groove and can be of different thicknesses that protrudes above the base. In this system, the position of the arch support is fixed, unlike the system we propose. On the other hand, there is patent US20120246971 [35] consisting of a device that provides support for the medial arch, heel, and metatarsal regions.