The effect of pulsed electromagnetic fields on hindfoot arthrodesis: a prospective study.

The aim of this study was to evaluate the effect of pulsed electromagnetic fields in a consecutive series of 64 patients undergoing hindfoot arthrodesis (144 joints). All patients who underwent elective triple/subtalar arthrodesis were randomized into control and pulsed electromagnetic field study groups. Subjects in the study group had an external pulsed electromagnetic fields device applied over the cast for 12 hours a day. Radiographs were taken pre- and postoperatively until radiographic union occurred. A senior musculoskeletal radiologist, blinded to the treatment scheme, evaluated the radiographic parameters. The average time to radiographic union in the control group was 14.5 weeks in 33 primary subtalar arthrodeses. There were 4 nonunions. The study group consisted of 22 primary subtalar arthrodeses and 5 revisions. The average time to radiographic union was 12.9 weeks (P =.136). The average time to fusion of the talonavicular joint in the control group was 17.6 weeks in 19 primary procedures. In the pulsed electromagnetic fields group of 20 primary and 3 revision talonavicular arthrodeses, the average time to radiographic fusion was 12.2 weeks (P =.003). For the 21 calcaneocuboid arthrodeses in control group, the average time to radiographic fusion was 17.7 weeks; it was 13.1 weeks (P =.010) for the 19 fusions in the study group. This study suggests that, if all parameters are equal, the adjunctive use of a pulsed electromagnetic field in elective hindfoot arthrodesis may increase the rate and speed of radiographic union of these joints.