A reply

Abstract

Ambulkar and Shankar make a number of interesting points about the complex nerve supply to the hip joint and the difficulty of using peripheral nerve blockade to provide high quality analgesia in total hip replacement (THR) patients. Whilst reviewing the literature for our meta-analysis of optimal analgesia for THR it became obvious that there were a large number of descriptive publications on the use of both peripheral nerve and neuraxial techniques to provide analgesia for THR, but few had been subjected to comparison by an appropriately designed, randomised, controlled trial. The main purpose of the review was to try and make sense of the variety of analgesic techniques described in the literature and provide evidence about their relative efficacy in providing analgesia for THR. A secondary purpose was to assess the relative risks and benefits of each technique for the Prospect Working Group to be able to make recommendations based both on analgesic efficacy and relative safety of the recommended techniques (http://www.postoppain.org). In outlining the complex nerve supply to the hip joint and the overlying tissues, Ambulkar and Shankar may wish to reconsider the relative importance of the posterior cutaneous nerve of the thigh, as the commonly used antero-lateral incision does not impinge on the territory of this nerve. The lateral cutaneous nerve of the thigh – a terminal nerve of the lumbar plexus needs to be considered for this approach. Indeed, the lateral cutaneous branch of the subcostal nerve (T12) can also supply innervation to the incision site on some approaches to the hip, and we believe that rather than trying to produce complete analgesia by monotherapy (regional anaesthesia), it may be preferable to use regional anaesthesia as one of the components of balanced analgesia (systemic non-steroidal inflammatory drugs, weak opioids and small rescue doses of strong opioids). The epidural technique described by Ambulkar and Shankar is an interesting, if somewhat labour-intensive, way of managing pain following total hip replacement. At such an early stage it is too soon to comment on its ultimate usefulness. Total hip replacement surgery is evolving rapidly with new surgical techniques, prostheses and instrumentation and suitably selected patients with no significant co-morbidity can be discharged from hospital within 48 h of primary total hip replacement. However, the epidural technique technique described by Ambulkar and Shankar would result in delayed discharge for this subgroup of patients. As anaesthetists, it is our responsibility to develop analgesic strategies that will match optimal analgesia with optimal recovery and match them to changing surgical circumstances. As our review pointed out, only well designed, prospective, randomised, controlled trials will help tease out the relevant risks and benefits of central neuraxial blockade, peripheral nerve blockade and systemic analgesics for optimal procedure-specific analgesia.