I have been an above-knee amputee for over 50 years. For the first 30 years, my prosthesis was balsa wood with a simple mechanical knee. I fell a lot, could only walk at one fixed speed, would sweat ...

You probably don’t want to lose a leg, but if you have to there are many options now that were unthinkable not long ago. That is, if you can afford them. A microprocessor knee — a prosthetic with some ...