I had my knee replace 11 days ago. A couple of days ago I started developing leg cramps. After I do a set of exercises, the muscles in my whole right leg seem to freeze up and I can hardly move. It is only one specific set of muscles, but it feels like my whole leg. I now have muscle relaxants to help me. " Just keepswimming just keepswimming, just keepswimmingswimmingswimming - What do we do? We swim, swim..."( I spend too much time watching "NEMO".) The nurse said that this happens all of the time. I even got a full night of sleep last night. Hurray!