For what its worth, here is my take on the "shaky leg syndrome". If you take even a strong athlete, and push a muscle until it fully fatigues, it will start to shake. Once a muscle has reached this point, it may feel shaky for a while after the workout, until it has had sufficient time to recover. This is not a bad thing, and is sign that you are pushing the muscle sufficiently to build strength. When I am doing pre season training for a sport, reaching the "shaky" point is how I know that I am pushing a muscle to an optimal level in order to most rapidly build strength. The difference is that after this surgery, it does not take very much at all to reach that level, but I still see it as a positive feedback on training level. Just be sure that your surgeon approves of this level of training at this time post surgery, and that you give a muscle that is pushed that hard, sufficient time to rest between workouts.
I would be concerned about pain, but shaky might be a good thing.
John/ Dr Gross/ left Biomet/ 6-16-08