osthetic socket.

Exploring the parametric socket design space demonstrates that biomechanical objective functions are in competition and illustrates the challenges associated with defining the 'best' socket design solution. As explored in our previous work (Steer et al. [@CR37]), by increasing the socket press fit, particularly in the mid-section, an increase in longitudinal shear around the main body of the residual limb was predicted. This resulted in a pressure reduction at the residuum tip coupled to a reduction in the internal strain around the distal tibia. By oversizing the socket (i.e. negative press fit), these peripheral shear forces were not generated, thereby increasing the distal pressure and soft tissue strain. These represent the competing fitness functions inherent in prosthetic socket design.

Introduction of the patella tendon bar and tibial crest rectifications provided an alternative method of off-loading the residuum tip beyond a uniform press fit. Fibula head relief is predicted to be effective in reducing the high pressure that was observed over this bony prominence for the total surface bearing socket designs, thus reiterating the importance of localised shape change beyond applying gross scaling to the limb shape (Goh et al. [@CR11]).

The sockets that emerged from the Genetic Algorithm exhibited features of both total surface bearing (TSB) and patella tendon bearing (PTB) manual socket design philosophies. One consistent feature along the Pareto Front for all virtual people was the patella tendon bar rectification variable, which saturated at its maximum limit. This is because no optimisation cost was associated with applying pressure over this region, which the Genetic Algorithm exploited to off-load the high-cost residuum tip region. This effect is observed clinically for the patella tendon bearing socket where prosthetists produce a marked rectification over the patella tendon to leverage its load bearing capacity. Although load tolerant, there clearly would be a load threshold for i