Exercise is not a cure all. and if you have really advanced osteoarthritis you have to be realistic about what can be achieved. So whether a good programme of exercise will stop you limping or remove your pain - I couldn't promise that. But exercise will make the muscles around your joint stronger and the joint more mobile no matter what stage of the disease you are at you should be in a better state than if you don't exercise. For example you should find you can walk further with less pain. And re: surgery, the stronger and fitter you are prior to the surgery you are likely to have a better outcome.