Evaluation of an articulated spacer for two-stage reimplantation for infected total knee arthroplasty: 28 cases

Purpose of the study Two-stage reimplantation remains the most popular solution for infected total knee arthroplasty. We have used articulated spacers since their introduction in 2000. We evaluated tolerance, joint motion under general anesthesia before reimplantation and also the infectious and functional long-term outcome. Material and methods Between June 2000 and April 2003, we implanted an articulated spacer in 28 patients who required revision of their total knee arthroplasty. Postoperatively, contact weight bearing was allowed with unlimited knee motion depending on pain control. Mean time between implant removal and reimplantation was eight weeks (range 6-16 weeks). Results There was one dislocation due to excessive play between the two components. Passive joint motion before reimplantation was 53 (range 5-80). At last follow-up, 24 patients were free of overt infection and all antibiotic regimens had been discontinued for at least 20 months (20-48 months). Two patients required a second two stage revision. One had an arthrodesis and in one only suppressive antibiotic therapy was possible. Discussion Spacer removal appears easy at reimplantation. Good knee flexion (greater than 40 in ten patients and greater than 60 in eight) facilitated exposure, avoiding the need for tilting of the tibial tuberosity in seven patients. Functional and infectious outcomes were similar to those reported in the literature. Conclusion The spacer appears to improve patient comfort between the two operations. It also facilitates the reimplantation procedure because of the easier exposure and greater knee flexion compared with a mono-bloc spacer or an external fixator. There must however be enough bone stock to hold the articulated spacer in place.