Goddammit Empire
Also, pfft, bionic prosthesis are still highly experimental, as far as I know based on that research, scientists at some university in chicago have a working prototype funded by the US army, and hope to have actual models in 3 to 5 years. The video I watched about it was posted in 2013, the events of Katawa Shoujo, I'm assuming take place in 2012, our story now is about current time 2014/2015. The bionic leg is still too experimental, extremely expensive, and based on the description given by rusher is nowhere near as quiet as is claimed.
At most, I would assume (and allow) that the C-leg would be the kind of prosthetic being used, the technology has been around since '97 and it uses microprocessors.