The symptoms of this condition are pain in the buttock area, numbness /tingling down the leg and the foot.
It has been commonly said that about 6% of sciatica problems are caused by the piriformis.
First of all consult your physician because sciatica is a serious problem and could cause lasting nerve damage with sensation and motor function. Then work with your Doctor and Physical therapist for help in differential diagnosis of what could be causing the symptoms. If it is piriformis syndrome these exercises may help. You need to be careful if you had a total hip replacement. You should not lift your hip > 90 degrees, internally rotate your hip, or cross your hip past the midline.
Some possible treatments are:
Stretch 3 x 60 seconds 3 x a day 5 x a week for 6 weeks. These would not be appropriate for someone with a total hip replacement that was a posterior approach which are most of them because the hip is being placed in a position of > 90 degrees.
3 x 30 seconds 2 x a day 5 x a week for 6 weeks
Another piriformis stretch
3 x 30 seconds 2 x a day 5 x a week 6 weeks.