Radiographic analysis of wedge allograft correction of angular malalignment in ankle fusion

Patients undergoing ankle arthrodesis often have coronal or sagittal plane malalignment. Correction of this deformity can be technically challenging. This retrospective review examines the use of an augmented interposition wedge allograft for deformity correction in ankle arthrodesis.

Nineteen patients underwent open ankle arthrodesis with interposition allograft at our institution since 2003. Sixteen patients had isolated ankle fusions and three patients had ankle fusions as part of a tibiotalocalcaneal fusion. A wedge of frozen tricortical iliac crest or femoral head allograft was cut to appropriate size and shape to correct angular deformity with an average maximum graft width of 9.5 mm. Fixation of the arthrodesis was with either a cannulated screw and plate construct or a lateral blade plate. Radiographs were reviewed to assess preoperative, initial postoperative and final alignment at the time of solid fusion. Fusion was assessed on plain radiographs by visualization of bridging bony trabeculae.

Seventeen of 19 patients (89%) obtained fusion at an average of 14.9 wks. Eleven ankles had preoperative tibiotalar valgus deformity with an average coronal alignment of 98.8 degrees and sagittal alignment of 110.5 degrees. Final coronal alignment was 90.9 degrees and sagittal alignment was 107.7 degrees. Eight ankles had varus deformity with an average coronal alignment of 77.4 degrees and sagittal alignment of 101.9 degrees. Final coronal alignment was 89.4 degrees and sagittal alignment was 107.4 degrees.

The tibiotalar joint fusion rate in this series compares favorably to historically published data for standard ankle fusion. Interposition allograft was an effective method for deformity correction in difficult ankle arthrodeses.