Nielsen ND - Given moderate or severe pain post-total hip arthroplasty (THA) is experienced by a significant subgroup of patients, and no inquiry has been performed to address the effect of an obturator nerve block (ONB) on pain post-THA, and an increased risk of fall has been observed in relation to a femoral nerve block which reduces pain post-THA, the researcher introduced a new nerve block – the iliopsoas plane block (IPB) – that has the potential to anaesthetize the hip articular sensory branches of the femoral nerve without inducing motor blockade. Although it has been concluded that IPB can potentially relieve the pain post-THA without inducing muscle weakness, but it is required to test this hypothesis in a clinical trial. An ONB does not seem to afford postoperative analgesia following THA by the posterior approach.