Abstract
Aim
The diagnosis of peri-prosthetic infection is sometimes difficult to assess, and there is no universal diagnostic test. The recommendations currently accepted include several diagnostic criteria, and are based mainly on the results of deep bacteriological samples, which only provide the diagnosis after surgery. A predictive score of the infection might improve the peri-operative management before repeat surgery after total hip arthroplasty (THA). The goal of this study was to attempt defining a composite score using conventional clinical, radiological and biological data that can be used to predict the positive and negative diagnosis of peri-prosthetic infection before repeat surgery after THA. The tested hypothesis was that the score thus defined allowed an accurate differentiation between infected and non-infected cases in more than 75% of the cases.
Method
104 cases of repeat surgery for any cause after THA were analyzed retrospectively: 61 cases of infection and 43 cases without infection. There were 54 men and 50 women, with a mean age of 70 ± 12 years (range, 30 to 90 years). A univariate analysis looked for individual discriminant factors between infected and uninfected case file records. A multivariate analysis integrated these factors concomitantly. A composite score was defined, and its diagnostic effectiveness was assessed by the percentage of correctly classified cases and by sensitivity and specificity.
Results
The score was defined with the following items which were individually weighted: body mass index (BMI), presence of diabetes (D, yes = 1, no = 0), mechanical complication (MC, yes = 1, no = 0), scar complication after THA implantation (SC, yes = 1, no = 0), fever (F, yes = 1, no = 0). The score was calculated as (0.09 × BMI) + (0.94 × D) − (1.34 × MC) + (17.55 × SC) + (1.22 × F) − 3.63. This composite score separated the infected (positive score) and non-infected (negative score) patients accurately in 78% of cases, with a sensitivity of 57% and a specificity of 93%.
Conclusions
Subject to prospective validation, this score could be a significant help to define the medico-surgical strategy during a reoperation of the hip prosthesis for whatever reason.
No funding from any part was received for the purpose of this study.
