Peripheral nerve blocks for analgesia after elective total hip arthroplasty.

A significant subgroup of patients suffer from moderate or severe pain after total hip arthroplasty (THA). Regional analgesia has the potential to reduce post-operative pain and thereby spare patients from opioids, but regional analgesia of the hip is complicated as the area is innervated by multiple nerves. However, the nociceptors of the hip joint are primarily innervated by the obturator and femoral nerves. The effect of an obturator nerve block (ONB) on pain following THA has never been investigated. A femoral nerve block is known to reduce pain after THA, but is unfortunately accompanied by an increased risk of fall. We have developed a novel nerve block-the iliopsoas plane block (IPB)-that has the potential to anaesthetize the hip articular sensory branches of the femoral nerve without causing motor blockade.