Knee arthrodesis with circular external fixation

Knee arthrodesis can enable limb salvage in patients with disability second ary to trauma, infected total knee arthroplasty, pyarthrosis, and other com plications. Historically, intramedullary nailing has resulted in the highes t overall knee fusion rates. However, intramedullary nailing is relatively contraindicated in the presence of active infection. Nineteen patients who underwent knee arthrodesis with circular external fixation were studied ret rospectively. Postoperative radiographs were evaluated for evidence of bony fusion, which was defined as trabecular bridging between the femur and tib ia. Patients were interviewed and graded using the functional assessment po rtion of the Knee Society clinical rating system. Fusion was successful in 13 of 19 (68%) patients. Overall, patients spent an average of 4 months 8 d ays wearing the circular external fixator. Average time to radiographic and clinical evidence of arthrodesis (defined as lack of motion across the fus ion site) was 4 months 18 days. No patient with successful fusion considere d himself or herself housebound. All but one of these patients require some form of assistive device for ambulation. Complications occurred in 16 of 1 9 (84%) patients overall. Superficial pin tract infection (55%) and nonunio n (32%) were the most common. Circular external fixation is an effective me thod for obtaining knee arthrodesis in patients who are not good candidates for intramedullary nailing.