Residual pain after THR can have a number of causes. Unless there was a major intraoperative inadequacy or early deep infection provided the patient indicates the greater part of the preoperative arthritic pain has been relieved and if other major clinical and radiological features are satisfactory remaining discomfort is all too easily attributed to a muscular origin with reassurances it will settle down! The senior authors attention was drawn to intrusive groin pain by a patient who had an otherwise uneventful bilateral (same sitting) THR. Right groin pain remained particularily marked on moving the leg getting in and out of her car on the drivers side.Clinical assessment Xray & CT scan & CT guided diagnostic injection suggested the symptoms were due to Psoas irritation perhaps due to a cement prominence underneath a proud edge of a flanged Charnley acetabular component. Through a direct anterior exposure this was shown to be so. There was evidence of Psoas Bursitis with a granular appearance.Symptoms were relieved by removing the flange and cement prominence and performing a partial psoas bursectomy and partial psoas tenotomy. Six similar cases are described. How to avoid or treat this annoying minor complication of a generally successful operation by attention to detail is discussed