Computer-aided parametric prosthetic socket design based on real-time soft tissue deformation and an inverse approach

The prosthetic socket provides the critical interface between the prosthetic device and the patient’s residual limb. Since each stump is unique in terms of morphology and mechanics, each socket should be patient specific. Computer-aided design solutions have been proposed in the literature. However, there is a lack of an efficient solution able to modify local information based on soft tissue deformation feedback to enhance the design process. The objective of the present work was to develop and evaluate a computer-aided design approach with real-time soft tissue deformation feedback and an inverse approach to optimize the stump–socket interaction. A computer-aided parametric socket design workflow was proposed. Soft tissue deformation was performed using a novel formulation of the mass-spring system. An inverse approach was proposed to estimate and optimize the stump–socket interaction. An interactive parametric design tool was also developed and evaluated. The proposed approach was applied on a CT-based dataset. Finally, the obtained design outcomes were compared with FE simulation outcomes for evaluation purpose. As results, a virtual socket prototype of the CT-based stump model was designed and illustrated by an interactive process. The comparison of stump–socket interaction behavior with FE simulation outcomes showed a very good agreement with a pressure absolute deviation error ranging from 1.44 ± 2.13 to 3.66 ± 4.56 kPa. Moreover, the contact pressures are below the pain-threshold curves, confirming the comfortability of the designed sockets according to the predefined criteria. The present study proposed a computer-aided socket design solution to locally enhance the socket geometry and mechanics. This opens new avenues to increase the design accuracy, reduce the design cost and give the involved patient a geometrically and mechanically fitted socket device. As perspectives, this process will be integrated with our available visual sensor fusion toward a complete computer-aided socket design system for lower limb prosthetic design and fabrication.