[Two-stage revision for prostheses infection in patients with bone tumor after knee prosthetic replacement].

OBJECTIVE: To evaluate the outcome of two-stage revision for prostheses infection in patients with bone tumor after knee prosthetic replacement.

METHODS: Between August 2003 and August 2010, 22 patients with prostheses infection, who underwent knee prosthetic replacement in limb salvage treatment because of bone tumor, received two-stage revision. There were 11 males and 11 females with an average age of 29.6 years (range, 15-55 years). Prosthetic infection occurred after primary replacement in 20 patients and after revision surgery in 2 patients from 15 days to 89 months after operation. According to Coventry and Fitzgerald classification, type I was found in 3 cases, type II in 15 cases, and type III in 4 cases. The time from infection to admission was 5-47 months (mean, 10.2 months). The results of bacterial culture were positive in 9 cases and negative in 13 cases. Two patients had fever and leukocytosis. In one-stage, the implants and infected tissue were removed, and an antibiotic cement spacer with an intramedullary nail was implanted. In two-stage, a new endoprosthesis was inserted after infection was controlled.

RESULTS: The C-reactive protein and erythrocyte sedimentation rate before one-stage debridement were significantly higher than those before two-stage revision (P < 0.05). All patients were followed up 5-63 months (mean, 23.6 months). Infection was controlled after one-stage debridement in 18 cases (81.8%); two-stage revision was performed in 17 cases, and 1 case refused to receive two-stage revision. Of 17 patients, 1 patient was amputated because of infection at 5 months after revision. Four patients (18.2%) underwent amputation because of failure to control infection after one-stage debridement. The limb salvage rate was 77.3% (17/22). One case of renal cell carcinoma with bone metastasis died of original disease after 1 year and 6 months of operation. The Musculoskeletal Tumor Society (MSTS 93) score was 69.4 +/- 12.7 at last follow-up.

CONCLUSION: Two-stage revision should be performed in time and it has good results in the treatment of prostheses infection in patients with bone sarcomas after knee prosthetic replacement.