[Infections after total hip arthroplasty].

Correspondence We welcome letters to the Editor concerning articles which have recently been published. Such letters will be subject to the usual stages of selection and editing; where appropriate the authors of the original article will be offered the opportunity to reply. Letters should normally be under 300 words in length, double-spaced throughout, signed by all authors and fully referenced. The edited version will be returned for approval before publication. Sir, We read with interest the paper in the September 2003 issue by Blom et al 1 entitled 'Infection after total hip arthroplasty'. The definition of infection is clearly essential when comparing infection rates. All authors agreed that superficial infection is far more common than deep infection, and there are many patients who have an inflamed wound who are given antibiotics either whilst in hospital or by the GP with no bacterial proof of infection. It would appear from their results, there were only seven of 1567 patients who had proven deep infection, an infection rate of 0.45%. The Royal Orthopaedic Hospital in Birmingham has taken a very different approach to investigating the incidence of infection following hip replacement. For the past 16 years, the Control of Infection Committee has monitored all positive cultures obtained from any patient who has previously undergone a total hip or knee replacement at this hospital. All cases where an organism has been cultured are investigated, and the infection labelled as either superficial or deep. If a superficial infection subsequently turns into a deep infection then the patient is reclassified, although the risk of this has been found to be low. 2 The hospital has information on 6842 primary total hip replacements in whom there is a 0.4% deep infection rate and a 1.7% superficial infection rate. For the 5863 total knee replacements the deep infection rate is 0.5% and superficial infection rate is 1.8%. Both of these results appear to be better than those reported in the Trent Arthroplasty Register, but are more in keeping with those reported from other large series. 3,4 We believe that neither our nor Blom's method of collecting data is perfect. Blom et al 1 have relied upon patients' recollections, which one would hope would be fairly accurate, while we have relied upon hospital records and, therefore, may have missed patients who have been treated elsewhere for post-operative infection. With the mandatory requirements coming into force in the near …