Increased Failure Rate of Modified Double Arthrodesis Compared With Triple Arthrodesis for Rigid Pes Planovalgus.

For rigid pes planovalgus deformities, modified double and triple arthrodeses have had high union rates and subjective outcomes reported. Increased rates of talonavicular nonunions after modified double arthrodesis have led to concern regarding this procedure. A retrospective medical record review was performed of patients who had undergone either a modified double (n = 9) or triple (n = 7) arthrodesis for stage 3 pes planovalgus deformity. Radiographs were reviewed for hindfoot alignment, bony union, and hardware failure. Data from questionnaires, including the Foot and Ankle Ability Measure and the Foot and Ankle Outcome Score, were obtained. No significant differences were found between the cohorts in terms of preoperative radiographic parameters or patient characteristics. The modified double arthrodesis cohort demonstrated a nonunion rate of 44% (4 of 9), but the triple arthrodesis cohort had a 0% (0 of 7) nonunion rate (p = .042). The Foot and Ankle Ability Measure activities of daily living, Foot and Ankle Outcome Score activities of daily living, and Foot and Ankle Outcome Score quality of life scores were significantly worse for the modified double arthrodesis than for the triple arthrodesis group. For patients with stage 3 pes planovalgus, modified double arthrodesis resulted in significantly greater rates of nonunion and incomplete union, with significantly inferior subjective outcome scores compared with triple arthrodesis for the same indication.