Session IX - Tibia

·*Nonunions Treated by Pulsed Low-Intensity Ultrasound

Dieter Gebauer, MD (a,b,e-Exogen (Europe) d-Exogen, Inc.); E. Mayr, MD (a,b,e-Exogen (Europe) d-Exogen, Inc.); E. Orthner, MD (a,b,e-Exogen (Europe) d-Exogen, Inc.), Orthopaedische Klinik, Tegernsee Orthopaedie, Tegernsee, Germany

Background: The characteristics of the fracture and/or the patient can delay the healing process and may lead to pseudarthrosis (nonunion). Open surgical intervention, debriding the nonunion site, and applying internal or external fixation, in most cases with bone grafting, is considered the "gold standard" of nonunion treatment, even if the primary treatment was the same at time of injury. The choices of treatment available include surgery, conservative treatment, electrical stimulation, shockwave therapy and, now, pulsed low-intensity ultrasound. In treating nonunions, surgical success rate averages 90 %, electrical therapy varies between 60% and 76% and shockwave therapy results in the literature are 62% to 67%. As with electrical or shockwave therapy, pulsed low-intensity ultrasound is surgically noninvasive and can be used in place of surgery. Pulsed, low-intensity ultrasound provides micromechanical stress and force in the form of acoustic pressure waves to the bone and surrounding tissue. Low-intensity pulsed ultrasound in treating nonunions was first reported by Xavier in 1983 with results demonstrating a 70% healing in pseudarthrosis. In 1996, Duarte reviewed all cases treated by him und his coauthors and reported an 85% success rate in 380 pseudarthroses. Heckman and Kristiansen, in their randomized, double-blind, placebo-controlled studies, both reported a 38 % healing acceleration in fresh tibia and distal radius fractures, respectively. Cook, et al. reported that the negative effects of nicotine on the fracture-repair process were mitigated by low-intensity ultrasound. The literature is clear in stating that an intervention is necessary to create healing in a nonunion, and there is a point beyond which spontaneous healing will not occur. Therefore, the nonunion is an ideal choice for a paired comparison since we are comparing the same patient's failure to heal with prior orthopaedic interventions to the results after low-intensity ultrasound therapy.

Materials and Methods: The inclusion criteria for this study was rigorous in defining nonunion: minimum of 8 months after injury, no surgical intervention during the prior 4 months before start of ultrasound, no radiographic healing, and the fracture line clearly visible in to views 90° apart. All cases of prescription of low-intensity ultrasound during the period of July 1995 to April 1997 were analyzed to determine whether they met the nonunion criteria. The primary efficacy parameter for the study was the percentage of healed cases. Secondarily, the heal time was of interest.

The patients applied the ultrasound device with coupling gel at home for 20 minutes per day until the nonunion was sufficiently healed to discontinue therapy. All cases had clinical and radiographic assessments at each follow-up. Nonunions were healed when the fracture was clinically healed 3 of 4 cortices of fracture line were bridged.

Results: There were 85 nonunion cases in 84 patients. The study group that met all nonunion criteria consisted of 67 cases, because 18 cases had to be excluded because of surgery in the prior 4 months or non-compliance. In the study group 39 % of the cases were female and 61 % male. The average patient age was 46 years. The average number of failed procedures was 2.057 of the 67 cases healed by low-intensity ultrasound which means a heal rate of 85 % with a very high significance as compared to their prior failed treatments. The average heal time was 5.5 months. The fracture age was 31.2 months on the average; that means much more than the demanded 8 months. The data were stratified by covariates. The heal rate was very equal for males and females. There was no statistical difference between different ages. The heal rate of non-smokers was higher than of those who were smokes or stopped smoking, but without statistical significance. In the comparison by bone there was a statistical difference for tibia and humerus and especially the scaphoid. The four failed scaphoids had fracture ages of more than 10 years. For the fracture age there was a statistical difference with cases with an age over 5 years. Between hypertrophic and atrophic nonunions no significant difference could be figured out. The patient's compliance with the device use was measured by an internal device microprocessor. It was good in 73 %, in 25 % of the cases no data were available. A long-term follow-up contact to the patient was performed. It showed that 93 % of the healed cases were still healed after 1.1 years; 7 % of the patient's could not be located. All individual country studies show heal rates over 85 %. World-wide the heal rate in 1,064 nonunions was 86%.

Conclusion: The only new treatment used for the nonunions was pulsed low-intensity ultrasound. This ultrasound is a safe, effective and predictable approach for the treatment of nonunion. It produces heal rates comparable to those by open surgery but with none of the attendant risks. It does not replace surgery, but it can be used when surgery should be avoided.