The Evaluation of the Healing Rate of Subtalar Arthrodeses, Part 2: The Effect of Low-Intensity Ultrasound Stimulation

Abstract

Arthrodeses of hindfoot joints is commonly used to treat a multitude of painful conditions and deformity. Use of adjuvant low-intensity ultrasound bone stimulation has demonstrated promising results in the treatment of acute fractures and fracture nonunions. The purpose of this 12-month prospective study was to evaluate the healing rate and clinical results of patients undergoing primary subtalar arthrodeses with adjuvant low-intensity ultrasound bone stimulation. Fifteen consecutive patients participated in the study. Routine radiographs and CT scans were obtained, and clinical outcomes gathered. The clinical and radiographic data were compared to a similar cohort of patients previously reported on that had not received ultrasound bone stimulation. The patients who received ultrasound bone stimulation showed a statistically significant faster healing rate on plain radiographs at 9 weeks (p = 0.034) and CT scan at 12 weeks (p = 0.017). A 100% fusion rate was noted. The American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score was also improved at 12 months postoperatively, a finding that was statistically significant (p = 0.026). This is the first paper, to our knowledge, to prospectively evaluate ultrasound bone stimulation in primary hindfoot arthrodesis patients. We were able to show significantly improved radiographic as well as clinical outcomes compared with a similar cohort of patients who did not receive adjuvant ultrasound stimulation. We believe that low-intensity ultrasound bone stimulation is indicated in primary hindfoot fusions, particularly in those patients at higher risk for nonunion.