Knee arthrodesis using a unilateral external fixator combined with crossed cannulated screws for the treatment of end-stage tuberculosis of the knee

BACKGROUND The treatment of end-stage tuberculosis (TB) of the knee remains a significant clinical challenge, and clinical data are lacking. This study aimed to retrospectively determine the outcome of single-stage knee arthrodesis with a unilateral external fixator combined with cannulated screws for the treatment of end-stage TB. METHODS Twenty-six patients with end-stage knee TB were treated by single-stage arthrodesis. All patients underwent open debridement and the insertion of a unilateral external fixator combined with crossed cannulated screws and received systemic antitubercular therapy. Clinical evaluations and radiographic analyses were performed after an average follow-up duration of 5.5 years. RESULTS The mean time to radiographic bone fusion was 5.6 months. Primary full union was achieved in 25 patients (96.2%) within 8 months, and the remaining patients achieved bone fusion at 14 months postoperatively. The mean post-operative alignment was 5.4° valgus and 12.5° flexion. The mean leg-length discrepancy was 2.8 cm. The mean VAS score improved from 67.3 before surgery to 16.2 at the last follow-up (P < 0.01), and the mean WOMAC score improved from 58.8 to 13.7 (P < 0.01). The erythrocyte sedimentation rate (ESR) and C-reactive protein level returned to normal in 25 patients by 3 months postoperatively. No recurrence in the target knee was noted. CONCLUSIONS Single-stage arthrodesis with a unilateral external fixator combined with cannulated screws can be regarded as efficacious for the treatment of end-stage knee TB. Additional studies are necessary to confirm the findings of our study.