Hi Thanks for posting on HCM I have read and understood your concern. Knee pain after knee replacement is common and may be due to stress/strain on knee elements.Since x ray reveal no problem, it is reasuring.Treatment options for such pain may include: -Different lines of pain drugs depending on pain intensity -Myorelaxants -Steroid shots ocassionally -Physiotherapy Many of these options may be used together for better results. I will advise you try a pain drug like aceclofenac, a myorelaxant like miorel, a local pain gel like voltaren gel and observe.If pain persists, you see your Doctor for evaluation and other treatment options. Hope this will help.You may write back if more concerns. Wish you good health Dr Mbuomboh