PREOPERATIVE KNOWLEDGE OF THE CAUSAL GERM AND ONE- OR TWO-STAGE HIP PROSTHESIS REPLACEMENT

Abstract

Purpose: We reviewed retrospectively 349 cases of infected total hip arthroplasty treated by prosthesis replacement. The surgical strategy, 127 single-stage procedures and 222 two-stage procedures, was determined by the surgeon on a case by case basis.

Material and methods: At least one positive sample during the clinical history was required for inclusion in the series. Results of all bacteriological samples collected pre- and intra-operatively were noted. Samples were considered reliable if obtained from a deep site (puncture, biopsy, intraoperative specimen) and non-reliable if obtained from any other site. We studied the agreement between preoperative and intraoperative samples, taking the intraoperative samples as the reference, in order to determine the effect of complete preoperative knowledge of the causal germ on the outcome of infection treatment at last follow-up.

Results: For single-stage replacement procedures, preoperative samples were reliable in 74 cases (58%) and non reliable in seven (6%); they were sterile or absent in 46 cases (36%). Intra-operative samples were positive in 103 cases (81%). Agreement between the preoperative and intraoperative samples was observed in 48 cases (38%). The rate of success was not different if the surgeon had or did not have reliable knowledge of the causal germ(s) preoperatively: successful treatment in 66 cases (89%) with knowledge and successful in 46 cases (87%) without knowledge. For two-stage procedures, preoperative samples were reliable in 155 cases (70%) and non-reliable in 15 (7%); they were sterile or absent in 52 cases (23%). Intraoperative samples were positive in 178 cases (80%). Agreement between preoperative and intraoperative samples was observed in 107 cases (48%). The rate of success was not different if the surgeon had or did not have reliable knowledge of the causal germ(s) preoperatively: successful treatment in 133 cases (86%) with knowledge and successful treatment in 56 cases (84%) without knowledge.

Conclusion: Reliable preoperative knowledge of the causal germ(s) did not affect the rate of success for single-stage or two-stage total hip arthroplasty replacement procedures. These findings do not corroborate the notion that it is absolutely necessary to recognise the germ(s) causing the infection before undertaking a single-stage replacement procedure.