Feasibility of designing, manufacturing and delivering 3D printed ankle‐foot orthoses: a systematic review

Abstract

BackgroundAnkle-foot orthoses (AFO) are prescribed to manage difficulty walking due to foot drop, bony foot deformities and poor balance. Traditional AFOs are handmade using thermoplastic vacuum forming which provides limited design options, is labour-intensive and associated with long wait times. 3D printing has the potential to transform AFO production and health service delivery. The aim of this systematic review was to determine the feasibility of designing, manufacturing and delivering customised 3D printed AFOs by evaluating the biomechanical outcomes, mechanical properties and fit of 3D printed compared to traditionally manufactured AFOs.MethodElectronic databases were searched from January 1985 to June 2018 according to terms related to 3D printing and AFOs. Studies of any design from healthy or pathological populations of any age were eligible for inclusion. Studies must have investigated the effect of customised 3D printed AFOs using any 3D printing technique on outcomes related to walking ability, biomechanical function, mechanical properties, patient comfort, pain and disability. Any other orthotic type or AFOs without a 3D printed calf and foot section were excluded. The quality of evidence was assessed using the GRADE process.ResultsEleven studies met the eligibility criteria evaluating 3D printed AFOs in healthy adults, and adults and children with unilateral foot drop from a variety of conditions. 3D printing was used to replicate traditional AFOs and develop novel designs to optimise the stiffness properties or reduce the weight and improve the ease of use of the AFO. 3D printed custom AFOs were found to be comparable to traditional custom AFOs and prefabricated AFOs in terms of temporal-spatial parameters. The mechanical stiffness and energy dissipation of 3D printed AFOs were found to be similar to prefabricated carbon-fibre AFOs. However, the sample sizes were small (n = 1 to 8) and study quality was generally low.ConclusionThe biomechanical effects and mechanical properties of 3D printed AFOs were comparable to traditionally manufactured AFOs. Developing novel AFO designs using 3D printing has many potential benefits including stiffness and weight optimisation to improve biomechanical function and comfort.Electronic supplementary materialThe online version of this article (10.1186/s13047-019-0321-6) contains supplementary material, which is available to authorized users.

Satisfaction with ankle foot orthoses in individuals with Charcot‐Marie‐Tooth disease

“…printing of AFOs in CMT populations. 23 Another aspect of AFO design that could benefit from further study is the effect of design on putting on and taking off the device. with and without their AFOs.…”

A digital workflow for design and fabrication of bespoke orthoses using 3D scanning and 3D printing, a patient-based case study

“…It is becoming an accessible and widespread technology, which has demonstrated numerous applications within medicine, from surgical planning 3 , education 4 , prostheses 5,6 and drug delivery 7 . 3D printed orthotic devices can be made to have comparable biomechanical properties to traditionally manufactured devices, with potential for fine control over these properties [8][9][10][11] . Orthotic designs made via computer-aided design (CAD), can be widely distributed through large open-source communities and then customised by the end-user 12 , allowing adjustment of the resulting model to meet the user needs.…”

The functional effect of 3D-printing individualized orthosis for patients with peripheral nerve injuries

“…3D printing enables design freedom by facilitating deviation from traditional design paradigms and hence allows the development of patient-specific orthosis. [ 4 , 32 ] In our case, the 3D-printed wrist orthosis was personalized by using CT-scanned 3D images and was printed out using thermoplastic polyurethane filament by a 3D printer. An AFO manufactured by 3D printing had a unique design considering a progress direction of foot center of pressure during gait cycle.…”