Low-intensity pulsed ultrasound in the treatment of nonunions

Background. Low-intensity ultrasound has demonstrated an acceleration of bo ne healing and more profound callus formation in animal and human clinical experiments. In this study, the effect of pulsed, low-intensity ultrasound was determined in established nonunion cases. Methods. The enrolled cases were reviewed for the time from their last surg ical procedure and evidence of no healing or progression of healing during the 3 or more months before the start of low-intensity ultrasound therapy t o determine whether the cases were established nonunions. Twenty-nine cases , located in the tibia, femur, radius/ulna, scaphoid, humerus, metatarsal, and clavicle, met the criteria for established nonunions. On average, the p ostfracture period before the start of ultrasound treatment was 61. weeks. Initial fracture treatment was conservative in 8 cases and operative in 21 cases. Additional treatments including bone grafting, reosteosynthesis, and other surgical procedures were performed an average of 52 weeks before the start of ultrasound treatment. Daily, 20-minute applications of low-intens ity ultrasound at the site of the nonunion were performed by the patients a t home. Results. Twenty-five of the 29 nonunion cases (86%) healed in an average tr eatment time of 22 weeks (median, 17 weeks). Stratification of the healed a nd failed outcome for age, gender, concomitant disease, bone location, frac ture age, prior last surgery interval, nonunion type, smoking habits, and f ixation before and during treatment showed a significant difference only in the smoking habit strata. Conclusion. Noninvasive ultrasound therapy can be useful in the treatment o f challenging, established nonunions.