I too have had my hip replaced and started having stabbing pain in that thigh. My ortho thought it was Bursitis, but after that didn't pan out, an MRI was done and they found that my L4&L5 discs were herniated. Read up on L4 problems and you may see your symptoms. Severe stabbing pain, throbbing pain etc because of nerves being pinched by the bad disc. I'm now seeing an Ortho that specializes in spine issues.