I think chuck and the others hit it right. The OA has twisted your body into a more efficient configuration to deal with the pain.
That means some muscles were overworked, some underworked or atrophied, some joints were under more pressure and some too lightly worked.
Now that you're back in line structurally, all that time in a different position has affected your body in many ways. This means your body has to work itself back into a normal support for your new and improved structure. If muscles have become atrophied, they have to come back, etc.
I went through strange twitches, pains and jolts. They worked themselves out (if not, check with your surgeon), and in some tiny respects, I still am working them out.
By about a year, though I was feeling like my machine was clicking on most gears and was synchronized. It took a bit, and free use of walking, both home and outpatient physical therapy, hitting the gym, doing balancing, etc.
All of that helps. I also had IT band pain, sometimes balance issues going up stairs, undeterminate limping, a slew of other little nits which passed by. Your body is shocked to find itself healthy, it needs a bit of time, help and patience to get back to fit.