High Rate of Fusion but High Complication Rate After Knee Arthrodesis for Infected Revision Total Knee Replacement.

BACKGROUND: Knee arthrodesis is a demanding technique regarding difficulties to achieve bone fusion, control of infection and its associated complications. The purpose of this study was to evaluate if knee arthrodesis should still be indicated after failed revision total knee replacement.
METHODS: This was a retrospective study of 45 patients. Age, gender, follow-up, pathogens, Charlson comorbidity index, time from primary arthroplasty to arthrodesis, number of previous procedures, surgical technique, functional capability assessed by the SF-12 score, limb-length discrepancy after arthrodesis, presence of radiographic knee fusion, and complications were recorded.
RESULTS: The mean age at the time of operation was 72 years. 29% of patients were men, 71% were women, and the mean follow-up was 8.5 years. The average Charlson comorbidity index was 4.5. The most common microorganisms isolated were Staphylococcus epidermidis (29%), Staphylococcus aureus (22%), and Pseudomonas aeruginosa (15%). In 20% of patients, no microorganism was identified, and in 37% of patients the infection was polymicrobial. Time from primary total knee arthroplasty to arthrodesis was 55 months, and patients underwent a mean of 3.9 previous surgeries. The surgical technique used was an intramedullary long nail in 95.5%. Functionally, 93.3% of patients walked with weight bearing. The SF-12 was higher after arthrodesis (p < 0.05). Mean limb length discrepancy was 2.4 cm. Among the group treated with long intramedullary nailing, 91.1% obtained tibiofemoral fusion. Complications occurred in 37.6% of patients.
CONCLUSIONS: Knee arthrodesis with a long intramedullary nail after failed infected revision total knee replacement has a high rate of fusion, but the complication rate is high. © Indian Orthopaedics Association 2020.