BackgroundThere is an increasing number of children with traumatic and congenital hand amputations or reductions. Children's prosthetic needs are complex due to their small size, constant growth, and psychosocial development. Families’ financial resources play a crucial role in the prescription of prostheses for their children, especially when private insurance and public funding are insufficient. Electric-powered (i.e., myoelectric) and body-powered (i.e., mechanical) devices have been developed to accommodate children’s needs, but the cost of maintenance and replacement represents an obstacle for many families. Due to the complexity and high cost of these prosthetic hands, they are not accessible to children from low-income, uninsured families or to children from developing countries. Advancements in computer-aided design (CAD) programs, additive manufacturing, and image editing software offer the possibility of designing, printing, and fitting prosthetic hands devices at a distance and at very low cost. The purpose of this preliminary investigation was to describe a low-cost three-dimensional (3D)-printed prosthetic hand for children with upper-limb reductions and to propose a prosthesis fitting methodology that can be performed at a distance.ResultsNo significant mean differences were found between the anthropometric and range of motion measurements taken directly from the upper limbs of subjects versus those extracted from photographs. The Bland and Altman plots show no major bias and narrow limits of agreements for lengths and widths and small bias and wider limits of agreements for the range of motion measurements. The main finding of the survey was that our prosthetic device may have a significant potential to positively impact quality of life and daily usage, and can be incorporated in several activities at home and in school.ConclusionsThis investigation describes a low-cost 3D-printed prosthetic hand for children and proposes a distance fitting procedure. The Cyborg Beast prosthetic hand and the proposed distance-fitting procedures may represent a possible low-cost alternative for children in developing countries and those who have limited access to health care providers. Further studies should examine the functionality, validity, durability, benefits, and rejection rate of this type of low-cost 3D-printed prosthetic device.

Introduction Advancements in computer-aided design programs, additive manufacturing, and open-source image editing software offer the possibility of designing, printing, and fitting transitional prosthetic hands and other prosthetic devices at very low cost. The development and use of 3D-printed transitional prosthetic devices to increase range of motion (ROM), strength, and other relevant variables would have a significant clinical impact for children with upper-limb deficiencies. Thus, the purpose of this study was to identify anthropometric, active ROM, and strength changes after 6 months of using a wrist-driven 3D-printed transitional prosthetic hand for children with upper-limb deficiencies. Materials and Methods Anthropometric, active ROM, and strength measurements were assessed before and after 6 months of using a 3D-printed transitional hand prosthesis. Five children (two girls and three boys, 3–10 years of age) with absent digits (one traumatic and four congenital) participated in this study and were fitted with a 3D-printed transitional hand prosthesis. Results There were significant hand × time interactions for the forearm circumference (p = 0.02), active ROM for flexion (p = 0.02), and extension values (p = 0.04). There were no significant hand × time interactions, however, for wrist flexion strength (p = 0.29), wrist extension strength (p = 0.84), active ROM for ulnar deviation (p = 0.5), active ROM for radial deviation (p = 0.25), and forearm skinfold values (p = 0.11). Conclusion Although durability, environment, and lack of printing standards for the manufacturing of 3D-printed prostheses are factors to consider when using these types of devices, the practicality and cost-effectiveness represent a promising new option for clinicians and those patients with upper-limb deficiencies living in developing countries. Thus, the Cyborg Beast transitional prosthetic hand represents a low-cost prosthetic solution for those in need of a transitional device to increase ROM and forearm circumference.

Background: A hand-held dynamometer (HHD) offers a reliable and valid method to quantify quadriceps strength in a clinical environment. While measures of peak strength provide functional insights, most daily activities are performed quickly and do not require maximum strength. Rate of torque development (RTD) measures better reflect both the demands of daily activity and athletic movements. The capacity to obtain RTD measures in clinical settings is possible with an HHD, but the validity of RTD measures has not been quantified. Hypothesis/Purpose: To determine the validity of an HHD to measure quadriceps isometric strength metrics compared to isometric strength measures obtained on an isokinetic dynamometer. It was hypothesized that the HHD would be a valid measure of peak torque and RTD at all time intervals when compared to the isokinetic dynamometer. Study Design: Descriptive laboratory study. Methods: Twenty healthy participants (12 male, 8 female) (age=23.7±2.9 years, height=174.6±10.1 cm, mass=76.4±15.9 kg, and Tegner=6.7 ±1.2) performed maximum isometric quadriceps contractions on an isokinetic dynamometer and with an HHD. Outcome measures included quadriceps peak torque and RTD at three intervals (0-100, 0-250 ms, and average). Pearson product-moment correlation coefficients and Spearman's rank correlation coefficient were used to determine relationships between devices. Bland-Altman Plots with Limits of Agreement (LOA) calculations were used to quantify systematic bias between measurement techniques. Results: There was a significant correlation between the isokinetic dynamometer and the HHD for peak torque (p<.001, r=.894) and all RTD measurements (p<.002, r=.807; ρ=.502-.604). Bland-Altman plot LOA indicated the HHD overestimated peak torque values (19.4±53.2 Nm) and underestimated all RTD measurements (-55.2±190.7 Nm/s to-265.2±402.6 Nm/s). Conclusion: These results show it is possible to obtain valid measures of quadriceps peak torque and late RTD using an HHD. Measures of early RTD and RTDAvg obtained with an HHD were more variable and should be viewed with caution.