Two-stage revision surgery for infected total knee replacements: reasonable function and high success rate with the use of primary knee replacement implants as temporary spacers.

Abstract

Two-stage revision surgery for infected total knee replacements remains the gold standard treatment. Articulating spacers are preferred to static spacers for improved functional outcome. Articulating spacers made of cement can be prone to fracture, may not be suitable for full weight bearing, create abrasion debris and necessitate second-stage revision surgery. An alternative is the use of primary knee replacement implants as temporary spacers. With this technique, implants are loosely cemented into place at time of revision, allow the patient reasonable mobility and an ability to fully weight bear and can obviate the need for second-stage surgery. A retrospective review of all patients undergoing revision for infection over two years was conducted. Patients were clinically assigned to single- or two-stage revision. Patients who had a temporary knee replacement, that is, a primary knee replacement used as an articulating spacer, were identified and contacted to complete an Oxford Knee Score. Time to second stage and recurrence was identified from the notes 23 patients received temporary knee replacements. Of these, one patient died, 13 proceeded to a second-stage revision and nine remain in situ. Median time to second-stage revision was 19weeks [range 11-27]. No patients had re-infection. Median follow-up for ongoing temporary knee replacements was 43weeks [range 24-90]. Four temporary implants had survived for longer than 1year. Median Oxford Knee Score was 26 [23-32] and satisfaction score was 8 out of 10 [8-8]. These early results show that knee replacement implants used as spacers provide a good alternative to cement-based articulating spacers with low re-infection rates. Their additional cost when compared with cement spacers is offset by the fact that many patients achieve adequate function and frail patients can avoid a revision procedure. Level of evidence Case series, Level IV.