Knee arthrodesis with external fixation in infected revision knee arthroplasty: a need to use patellar autograft?

Objective: Our study aimed to evaluate the outcomes of knee arthrodesis with external fixation in patients undergoing revision surgery due to an infection following knee arthroplasty. Method: The mean age of the patients recruited in the study was 71.1 years (range: 58-84). Of the 40 patients who underwent revision total knee arthroplasty between 2010 and 2014, nine patients developed recurrent infections, which required knee arthrodesis with uniplanar and biplanar external fixation. The patient population consisted of eight females and one male. The ipsilateral patella was used as the autograft in all patients. Complete union was achieved in all patients. Infection was eradicated after debridement and arthrodesis in all patients. The mean duration of follow-up was 16 months (range: 10-22). The elapsed time of external fixation was 4 months (range: 3-5). The exclusion criteria were fracture or septic arthritis sequelae and those undergoing knee arthrodesis due to congenital diseases. Results: Antibiotic therapy targeted to the infectious agents based on the culture results obtained during the surgery was initiated. All patients were monitored for reductions in C-reactive protein (CRP) levels and sedimentation rates. A superficial pin site infection was detected in all patients at the base of the proximal Schanz pins that were inserted into the femur. All patients responded well to the antibiotic treatment. A mean shortening of 2.6 cm (range: 2-5) was observed. No patient reported post-arthrodesis pain, and infection was eradicated in all patients. Conclusion: In the presence of a persistent infection in revision total knee arthroplasty, we suggest that microbial eradication and patellar autografting in addition to external fixation of the knee arthrodesis represents a good option for a successful fusion.