The patella rests inside a groove in addition to the femur called the trochlear groove. When you bend and straighten your knee, the patella moves forwards and backwards inside this groove. Kneecap replacement surgical procedure does require anaesthesia and the choice is possibly standard anaesthesia or spinal anaesthesia (where you would remain awake, https://kneecapreplacement53951.blogdanica.com/34163178/a-secret-weapon-for-knee-cap-replacement