Structural evaluation of lower-limb prosthetic sockets for running– Part 2: exploratory application of an innovative test bench to various socket designs

• No dedicated standard or common guidelines exist for the structural characterization of running specific sockets. • This study proposes and applies an innovative testing method to various sprinting socket designs of two Paralympic gold medalists. • Results were used to inform the production of sprinting sockets for two athletes competing at the 2024 Paris Paralympic Games. Lower-limb sockets for sprinting prostheses must withstand high loads. Various carbon-fiber laminated socket designs can be conceived, both for transfemoral (TF) and transtibial (TT) amputations, that differ in layup, resin and distal connector. To date, no quantitative data is available on their different ability to sustainable loads, on their weight and fabrication complexity, limiting the formulation of manufacturing recommendations. The aim of this study was to start filling this gap by applying an innovative test method for the mechanical characterization of running-specific sockets to various socket designs conceived for the 2024 Paralympic Games. Moreover, we aimed at exploring the repeatability of TT socket production and the ability of the test method to detect socket manufacturing issues. Fourteen TF (7 pairs, one per condition) and 9 TT carbon-fiber laminated sprinting sockets, which differed in terms of layup, resin or distal adapters, were tested. TF sockets were assessed under two critical conditions, while TT sockets were assessed under a single critical condition. Based on the results from static loading, we identified a TF and a TT design that could withstand over 5400 N and 6900 N, respectively, weighting less than 450 g and with a simple setup. For TT sockets, this design also showed better manufacturing reproducibility. Finally, results confirmed that the test method was able to detect known manufacturing issues reporting a decreased maximum sustainable load for the faulty parts. To draw definitive conclusions, these results will need to be confirmed by cyclic testing.