This is a case report of a 33-year-old woman who presented with an eight year history of deep left knee pain. The pain was originally diagnosed as deriving from osteoarthrosis of the hip secondary to dysplasia, however, the same pain returned at seven months, and again at 10 months, after successful hip resurfacing arthroplasty. Six to eight weeks after the start of the second relapse of referred knee pain, the patient sought acupuncture treatment at the British Medical Acupuncture Society's London Teaching Clinic. A single myofascial trigger point was found in iliopsoas that reproduced the patient's pain. It was successfully treated with two sessions of electroacupuncture applied directly to the point. Pain referral to the knee from trigger points in the upper part of rectus femoris is well recognised, however, this pattern of referral from iliopsoas has not been described previously.