Since surgery I've had this pain. Do you still have pain? Go see your surgeon!! I have been diagnosed with "start-up pain". It only occurs when I hv been sitting or sleeping for extended periods of time and try to walk. It takes 10-15min. to straighten up. I had both the 3 mos and 6 mos x-rays side by side and the latter shows some miniscule space between the prosthetic and the new bone growth. Having a CT scan in October and will report the results.