Postoperative Pain Relief Following Total Hip Arthroplasty. A Comparison Between Intrathecal Morphine (IM) and Local Infiltration Analgesia (LIA)

Postoperative pain following total hip arthroplasty (THA) (1) is often considered moderate to severe and can therefore influence the postoperative course of event and result in delayed postoperative mobilization and prolonged hospitalization. It is therefore necessary to find the most optimal method for alleviation of pain for these patients. Traditionally, this has been managed by epidural analgesia, continuous peripheral nerve blocks, parental- or spinal opioids. Recently, Drs Kerr and Kohan at the Joint Orthopaedic Centre in Sydney, Australia developed a local infiltration analgesia (LIA) technique. The technique was introduced in Scandinavia during 2001 and has been shown to be efficacious during knee surgery. The LIA technique is based on a systemic infiltration of a mixture of a long-acting local anaesthetic (ropivacaine), a non steroidal anti-inflammatory drug (ketorolac), and epinephrine into the tissue around the surgical field to achieve satisfactory pain control with little physiological disturbance. A catheter is left from the skin and into the joint cavity, allowing repeated injection on the morning after surgery (10). Effective pain relief with early mobilization and reduced hospital stay has been reported following total knee arthroplasty and, recently, following unicompartmental knee arthroplasty. The aim of this study is to assess whether LIA technique is equi-efficacious to intrathecal morphine, the standard of care in our hospital.