Microbiological profile and outcomes of two-stage revision hip arthroplasty

Prosthetic joint infection (PJI) is one of the most challenging cases that confront modern orthopaedics. Two-stage revision, which is the standard of care for PJI, is the preferred mode of treatment for these infections.

To study the microbiological profile of prosthetic joint infections (PJI) in the hip and to assess the efficacy of a two stage revision surgery for PJI. We also aimed to study the sensitivity and specificity of ESR and CRP in the diagnosis of PJI.

The microbiological profile, clinical and radiological outcomes of 22 patients who had a two-stage revision for PJI of the hip between 2013 and 2017 were retrospectively analysed. PJI was defined using the criteria provided by the International Consensus Statement on PJI 2013.

Staphylococcus aureus was found to be the most common organism in PJI. Debridement was successful in removing the organism in 74% of PJI. At the time of re-implantation (second stage), six joints grew organisms that were different from that isolated at the index debridement - coagulase-negative staphylococci (3cases) and enterococci (3cases). Other infection parameters for these patients were negative. None of the patients who had two-stage revision surgery had clinical evidence of reinfection or radiological evidence of loosening at a mean of 2-year follow-up. An ESR cut off of >30mm/hr had a sensitivity of 75% and specificity of 88% in predicting PJI. A CRP >10mg/L had a sensitivity of 75% and specificity of 69%. The sensitivity and specificity of using both ESR and CRP cut-offs in the diagnosis of infection were 57% and 94%, respectively. The positive predictive value was 94% and negative predictive value was 56%.

The outcomes of the study justify a two-stage revision arthroplasty for PJI of the hip. The use of ESR and CRP as screening tests for the success of debridement has value - but should be interpreted with caution.