3D Foot Scanning and Customized 3D-Printed Foot Orthotics to Reduce Pressure on the Feet of Healthy Adults

The number of people with diabetes mellitus worldwide is increasing rapidly and is expected to rise to 439 million by 2030, or 7.7% of the total adult world population. The complications that can arise as a result of chronic diabetes represent a major problem in terms of clinical treatment, socio-economic consequences and costs to the health care system. One of the most serious complications is a diabetic foot, which is characterized by neuropathy, ischemia and limited joint mobility and makes the foot vulnerable to foot ulcers and possible amputation. Various interventions are being investigated to prevent foot ulcers, including custom-made foot orthotics (CFOs), also known as foot orthoses. The latter allows the health professional to achieve a number of functional effects, of which the redistribution of the plantar pressure load is the most valuable, especially in patients with so-called risk feet. The use of integrated computer-aided design and computer-aided manufacturing systems to produce CFOs has become increasingly popular over the past decade. In practice, this digital workflow comprises three different phases. First the (3D) foot shape of the patient is recorded, then the arch support is designed using special software and finally the device is made using a subtractive or additive manufacturing process (3D printing). As a result, it can be concluded that the first two phases are decisive for determining the geometric characteristics of a CFO, while the last phase is more critical for selecting the material properties. As for the first phase, digital approaches were developed, such as 3D optical scanning that allows the researcher to scan body parts directly, providing a robust base for determining a CFO's geometrical features. The anthropometric foot parameters examined were worth investigating, but exclusively zero-dimensional in nature, providing limited insight when assessing the 3D fit of a custom made foot orthotic. Thus, current knowledge in this