BackgroundTreatment of an acute total hip arthroplasty (THA) infection aims at control of the infection with retention of the implant by surgical debridement and antibiotic treatment. There is no clear evidence whether a single surgical debridement is sufficient or whether multiple procedures are necessary for optimal treatment.MethodsFrom a prospective database of patients with acute THA infection, we retrospectively reviewed 68 patients treated in 2 large teaching hospitals. Hospital S used a protocol in which each patient received a single surgical debridement and only additional surgery if infectious symptoms persisted (group S; n = 33). In hospital M, patients always received multiple surgical debridements (group M; n = 35). Both groups received systemic antibiotic treatment. Removal of the implant or persistent infection at follow-up was considered failure of treatment. Mean follow-up of the patients was 5 (2–11) years.ResultsMean time between implantation and debridement was 19 days. 4 patients in group S were considered failure, as opposed to 10 patients in group M (p = 0.09). 9 patients in group S had additional surgery, which resulted in 3 of the 4 failures. At final follow-up, 30 patients in group S and 33 patients in group M had a good clinical result (p = 0.6).InterpretationIn patients with acute THA infection, a single debridement with only additional surgery on indication appears to be at least as successful for retention of the primary implant and control of infection as a strategy with multiple surgical debridements.

Aspiration arthrography using an iodinated contrast medium is a useful tool for the investigation of septic or aseptic loosening of arthroplasties and of septic arthritis. Previously, the contrast media have been thought to cause false negative results in cultures when present in aspirated samples of synovial fluid, probably because free iodine is bactericidal, but reports have been inconclusive. We examined the influence of the older, high osmolar contrast agents and the low osmolar media used currently on the growth of ten different micro-organisms capable of causing deep infection around a prosthesis. Five media were tested, using a disc diffusion technique and a time-killing curve method in which high and low inocula of micro-organisms were incubated in undiluted media. The only bactericidal effects were found with low inocula of Escherichia coli and Pseudomonas aeruginosa in ioxithalamate, one of the older ionic media. The low and iso-osmolar iodinated contrast media used currently do not impede culture. Future study must assess other causes of false negative cultures of synovial fluid and new developments in enhancing microbial recovery from aspirated samples.