Proprioception is the body's awareness of itself. Certain nerve cells sense movement, position and other factors such as muscle tension and provide feedback into the central nervous system. Without proprioception, it would be difficult to do most ordinary things, e.g., walking, holding an egg without crushing it or holding a rock without dropping it, without actually looking at our limbs to know their position and how they were responding to the output signals our brain is sending them. If your wife senses that her leg is bent when it is not, and can't feel it due to numbness, then it could be the case that the proprioceptive inputs are misfiring or that the brain is misinterpreting what it is receiving. Anyways, that's just my hypothesis. You may wish to discuss these problems with a doctor for a better interpretation. Has she ever tried any type of physical therapy such as massage? That might be helpful via stimulating the nerves.