Electronic Letters to:

Arthroplasty: S. Hu, Z.-Y. Zhang, Y.-Q. Hua, J. Li, and Z.-D. Cai A comparison of regional and general anaesthesia for total replacement of the hip or knee: A META-ANALYSIS J Bone Joint Surg Br 2009; 91-B: 935-942 [Abstract] [Full text] [PDF]

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A comparison of regional and general anaesthesia for total replacement of the hip or knee

Richard Brull, Alan J.R. Macfarlane   (31 July 2009)

A comparison of regional and general anaesthesia for total replacement of the hip or knee 31 July 2009
Richard Brull, Associate Professor Department of Anesthesia and Pain Management, Toronto Western Hospital, Toronto, Canada, Alan J.R. Macfarlane Send letter to journal: Re: A comparison of regional and general anaesthesia for total replacement of the hip or knee richard.brull{at}uhn.on.ca Richard Brull, et al.	Sir, We congratulate Hu et al for attempting to address whether regional anaesthesia (RA) is superior to general anaesthesia (GA) for total hip and knee replacements. However, in our opinion, not all the conclusions are relevant to current practice. Over half of the 21 trials included in the meta-analysis were published almost 20 years ago. During this time post-operative care and surgical techniques have improved considerably. Similarly, RA has advanced due to enhanced needle and catheter technologies, block placement techniques and infusion pumps. The authors do not address the present resurgence of peripheral nerve blocks, which provide equivalent analgesia with reduced side effects compared with epidural analgesia for total knee replacement.1 Similarly, new thromboembolic prophylaxis regimes have been introduced since many studies in the meta-analysis were published. Indeed, subgroup analysis of patients receiving thromboprophylaxis found no difference between RA and GA in Hu et al's study. Therefore the statement that RA reduces the incidence of thromboembolism must be viewed with caution, as the authors duly note. The authors found no difference in length of stay in their meta-analysis yet conclude that "epidural anaesthesia/analgesia has been shown to shorten hospital stay". Length of stay is also often a secondary, underpowered outcome. Furthermore, the mean durations of hospital stay in the source articles were up to 22 days, which differ considerably from the current practice of protocolised clinical pathways. The authors also found a reduced need for transfusion, consistent with previously published meta-analyses.2 However, with current restrictive transfusion strategies and pre-operative blood conservation therapies, it may become difficult to demonstrate benefits of RA. Finally, data were not weighted by trial quality. The majority of studies comparing RA and GA for major arthroplasties are Level II evidence. Therefore, in summary, whilst we agree that RA reduces pain and opioid-related side effects, further high-quality, contemporary research is required to investigate whether RA reduces mortality, thromboembolism, or hospital stay, or facilitates rehabilitation after major arthroplasty. This, admittedly, may be a challenge. R. Brull, Associate Professor, A.J.R. Macfarlane, Department of Anesthesia and Pain Management, Toronto Western Hospital, Toronto, Canada. 1. Fowler SJ, Symons J, Sabato S, Myles PS. Epidural analgesia compared with peripheral nerve blockade after major knee surgery: a systematic review and meta-analysis of randomized trials. Br J Anaesth 2008;100:154-64. 2. Guay J. The effect of neuraxial blocks on surgical blood loss and blood transfusion requirements: a meta-analysis. J Clin Anesth 2006;18:124-8.