Abstract
Objectives
The appropriate treatment for chronically infected TKR is controversial. One-stage exchange is believed to be possible only in selected cases, but the respective indications and contra-indications and the criteria of selection are not fully validated. We wanted to test the relevance of the commonly used selection criteria by comparing two groups of patients: the control group operated on with a routine one-stage exchange without selection criteria, and the study group operated on by one stage exchange on selected patients only. We hypothesized that selected one-stage exchange gives fewer failures than routine one-stage exchange procedure.
Methods
We performed a retrospective study of 108 cases selected in a database of 600 patients with an infected total knee arthroplasty. The database resulted from a French multicenter trial of specialized surgeons in reference institutions, including all consecutive cases operated on between 2000 and 2010. There were 64 women and 44 men with a mean age of 69 years. All patients were followed-up for a minimal period of two years or when septic failure occurred. The patients were divided into two groups: patients operated on in a center using a routine one-stage exchange policy, and patients operated on in a center using a selected one-stage exchange policy. Patients were matched in the two groups according to body mass index and the aspect of the wound at the initial examination (one scar, several scars, presence of a fistula). The results were expressed as: free of infection, relapse or persistence of the index infection, occurrence of a new infection. The repartition was compared in the two groups by a Chi² test at a 0.05 level of significance. The cumulative survivorship was plotted with infection recurrence for any reason as the end point.
Results
The two groups were comparable for age, gender, previous procedures, microorganisms and other risk factors. One stage exchange was successfully completed in all cases. 77% of the patients were considered infection free at the last examination. There was no difference in the failure rate between the two groups. No prognostic factor could be validated. Among the 23% failure cases; 8% were considered as failures by relapse or persistence of the index infection, and 15% by occurrence of a new infection: there was no difference of this repartition between the two groups. The 5-year survival rate was 68%, and no difference was observed between the two groups. No prognostic factor could be validated. Among the 23% failure cases; 8% were considered as failures by relapse or persistence of the index infection, and 15% by occurrence of a new infection: there was no difference of this repartition between the two groups.
Conclusion
The use of the generally validated selection factors to decrease the failure rate after one stage exchange for chronically infected total knee replacement was not effective. Routine one stage exchange may be used for any clinical case without increasing the failure rate.
