USE OF AN ARTICULATED SPACER FOR TREATMENT OF KNEE PROSTHESIS INFECTIONS WITH TWO OPERATIVE TIMES (2002)

Purpose: Infection is a serious complication of total knee arthroplasty. Surgical strategies based on removal-reinsertion of the prosthesis in two times with antibiotic therapy has proven its efficacy. The use of a spacer between the two operations has been proposed to facilitate reimplantation. Since 1993, we have used this two-time procedure with an articulated spacer in an attempt to optimise functional outcome yet maintain anti-infection efficacy. We report our experience. Material and methods: This retrospective series included 28 patients, 21 women (75%) and seven men (25%) who underwent surgery between December 1993 and February 2000.Mean age of the patients at revision was 67 years (18–83). Medical and surgical risk factors for infection were present in 64% and 54% of the cases respectively. Delay between prosthesis surgery and onset of the first signs of infection was 29 months (four days–222 months). A single-germ infection was involved in 18 cases (64%) and a multiple-germ infection in nine (36%). The infection was acute in 32% of the cases and chronic in 68%. There were eight fistulae (28%). Bacteriology reported staphylococcal infection in 25 cases (including 13 S. epidermidis), streptococcal infections in five, anaerobic germs in seven (corynebacterium in five) and Gram-negative germ (pseudomonas) in one. Delay between diagnosis of infection and insertion of the articulated spacer was 11 months (four days–62 months). The first operation consisted in removal of the prosthesis, wide excision of the synovial and infected tissues and insertion of the two articulated pieces, modelled with antibiotic-impregnated cement. Weight-bearing was authorised with crutches and an articulated brace. Rehabilitation exercises were performed to maintain joint amplitude. The prosthesis was reimplanted three months later (1.5–7 months). All prostheses were reimplanted with cement: two prostheses with posterior preservation, 20 posterior stabilised prostheses, and six hinge prostheses. The patients were given antibiotics for eleven months (1–25 months). The IKS score was used to assess functional outcome. Cure of infection was assessed on clinical, biological and radiographic findings. Results: All patients were seen at a mean follow-up of 35 months (8–78). Follow-up was greater than 24 months in 68% of the patients. We had three cases (11%) of recurrent infection: one acute infection and two septic loosenings. At reimplantation, we had complications in seven patients (25%) ten of whom required revision surgery, six for mechanical complications (three dislocations, three aseptic loosenings). Mean IKS score was 136 points (50–190) with 79 points (30–100) for the knee and 67 points (20–90) for function. Mean flexion amplitude was 94° (45–115°). Discussion, conclusion: With this method, joint mobility can be maintained between the two operations, greatly improving patient comfort. The mid-term results in terms of infection cure have been satisfactory (89% cure). Nevertheless, the final functional result can be disappointing, due to the persistence of pain (low-grade infection, difficult implant fixation…). The removal-reinsertion strategy using a single operation would in our opinion still have its indications.