Supramalleolar Osteotomy Using Circular External Fixation with Six-Axis Deformity Correction of the Distal Tibia

Background: Supramalleolar osteotomy using circular external fixation with six-axis deformity correction is a rarely reported treatment method particularly well-suited for complex multidimensional deformities of the adult ankle. The purpose of this study was to assess the accuracy of deformity correction and change in functional status using this technique. Methods: We present a retrospective review of 52 patients who underwent supramalleolar osteotomy with application of the Taylor Spatial Frame (Smith & Nephew, Memphis, TN). Mean age was 44 (range, 18 to 79) years. The primary outcome was change in preoperative to postoperative distal tibial joint orientation angles. Coronal and sagittal plane joint orientation angles were measured for all 52 enrolled patients. The secondary outcome was change in AOFAS scores which were available for 31 patients. Results: Twenty-two patients had oblique plane deformities. The mean time in frame was 4 (range, 2 to 11) months, and patients were followed for a mean of 14 months after frame removal. All aggregate postoperative distal tibial angles underwent a significant improvement (p < 0.05) and were within 0 degrees to 4 degrees of normal in the various deformity groups. Average preoperative AOFAS score was 40 (range, 12 to 67) and average postoperative AOFAS score was 71 (range, 34 to 97; p < 0.001). Complications included two patients with nonunions at the osteotomy site that healed with further treatment. Three patients went on to have ankle fusion. Conclusion: We feel that supramalleolar osteotomy using circular external fixation with six-axis deformity correction was an effective method for correction of distal tibial deformities in the adult population, particularly for those patients with complex oblique-plane deformities, associated rotational deformity, a compromised soft tissue envelope, or a prior history of infection.