# Clinical Assessment of Customized 3D-Printed Wrist Orthoses
###### Abstract
The personalized inner structure could be combined with three sizes of outer injection molding in order to reduce the additive manufacturing time of the inner part. The time cost was estimated be reduced by two-thirds of that of the additive manufacture of the whole orthosis [8]. [PERSON] et al. attempted automated computer-aided design modeling for customized limb orthosis design and manufacture. They conducted collision tests on an arbitrary 3 mm gap, which was a comfortable loose fit for less immobility between the patient's body and orthosis. However, this concept has not been studied for clinical purposes [9; 10; 11; 12]. A clinical application implemented by [PERSON] et al. used an additive manufacturing technique to produce a functional splint for partial rupture of the Achilles tendon. The advantages of using the 3D-printed functional splint in the immobilization stage include its easy control and monitoring measures, and the substantial reduction in further lesion deterioration of the Achilles tendon in terms of rupture [13]. A systematic review concluded that the 3D-printed orthoses/casts appear to be comfortable, provide adequate immobilization, and have pleasing aesthetics [14]. Another recent systematic review assessed the literature that addressed the effectiveness of 3D-printed orthoses for traumatic and chronic hand conditions, and to identifying knowledge gaps [15]. Both reviews stated there is a need for well-designed controlled trials including patient-related outcomes, production time, and cost analysis. More recent literature surveys the personalized 3D-printed forearm braces on the design requirement, materials used, technical requirements, and preclinical and clinical results [16]. The surveys acknowledge that the expensive equipment, lack of appropriate software and scanning tools, and lack of highly skilled clinicians are all factors preventing the implementation of 3D-printed orthoses into current clinical practice. An alternative to plaster cast treatment in pediatric wrist fracture [17; 18; 19] was precisely the demonstrated feasibility and safety of 3D-printed brace. It proved to be simple to use and accurate in patient-specific 3D-printed casts that were safe and well-toleratedin children. [PERSON] et al. investigated left-right differences in wrist circumference of 100 healthy volunteers (age 50 years or older), and the results showed the difference ranged between 0 and 20 mm (mean 3 mm) [20]. They mirrored the scanned unaffected wrist and adapted the difference between the mirrored wrists and post-traumatic swelling wrist. However, the three-point fixation brace failed to prevent secondary fracture displacement. In terms of comfort, twelve healthy volunteers were fitted with a 3D-printed brace and fiberglass cast in separate sessions for comfort evaluation when perform the tasks in a normal time. Both castings demonstrated a similar objective function. However, patient's satisfaction, comfort, and perceived function were superior in the 3D-printed casts [12; 21]. It was capable of exerting appropriate mechanical correction loads on specific areas to maintain optimal alignment of a fracture forearm to achieve the favorable clinical efficacy and patient comfort [22]. Although 3D-printed orthoses demonstrate some potential innovations, particularly in appearance, one may question their efficacy from a medical point of view. The lack of science-based, data-centric solutions provides ample motivation to seek better and verifiable results. Therefore, we adopted pres pressure profiles and clearance profiles at certain regions of forearm to assess the effectiveness of immobility from user experiences in comfort levels when wearing a 3D-printed brace. A data-centric, science-based approach was warranted to produce clinically verifiable results.