Knee arthrodesis using a unilateral external fixator for the treatment of infectious sequelae

Objectives: We evaluated the results of arthrodesis using a monolateral external fixator for the treatment of septic sequelae of the knee joint. Methods: Eleven patients (4 males, 7 females; mean age 60 years range 29 to 75 years) underwent arthrodesis using a monolateral external fixator. Indications for arthrodesis were infected total knee prosthesis (n=6), septic arthritis sequelae (n=4,), and infected distal femoral tumor prosthesis (n=1). Eight patients had active infection, of these, seven patients initially underwent complete clinical and laboratory eradication of infection with debridement, application of antibiotic-impregnated cement spacer (n=6), and parenteral antibiotics. Resection guides of total knee arthroplasty were used to create wide bleeding femoral and tibial bone surfaces. Biplanar or uniplanar monolateral external fixation was applied for a mean of eight months (range 5 to 12 months). The mean follow-up was 28 months (range 7 to 69 months). Complications were evaluated according to the Paley's classification. Results: Fusion was achieved in all the patients. There were no recurrent infections. No remarkable shortening developed following the procedure. All the patients could walk without walking aids, except for one patient who further required lengthening for marked shortening due to previous wide tumor resection. Shortening was 3 cm in one patient with infected total knee prosthesis, while it ranged from 1 cm to 2 cm (mean 1.4 cm) in the remaining patients. Pin tract infections were seen in five patients, all of which were successfully treated with oral antibiotics and local wound care. Conclusion: Knee arthrodesis using a monolateral external fixator is associated with a high fusion rate and a low complication rate, and provides a more comfortable treatment option compared to a circular external fixator.