Can low intensity pulsed ultrasound (LIPUS) be used as an alternative to revision surgery for patients with non-unions following fracture fixation?

Abstract

Background: Non-union is a significant complication of fracture fixation surgery, and can negatively impact a patient's quality of life. Low intensity pulsed ultrasound (LIPUS) has been used to treat delayed or non-unions previously in the literature. The aim of this study was to determine the success rate of LIPUS treatment in patients with chronic fracture non-unions, and to establish the effect of systemic or local factors on its success.

Methods: This was a retrospective, observational study which included all patients undergoing LIPUS treatment in a single institution. Patients deemed suitable for LIPUS underwent treatment for a period of 6 months from initiation. They were followed up with sequential radiographs to assess union at intervals of 6 weeks, 3 months, 6 months and 1 year. LIPUS treatment was considered to be successful when patients achieved clinical and radiological union, without the need for revision surgery.

Results: A total of 46 patients were included in the study; 8 were lost to follow - up, leaving 38 patients for the final analysis. The mean age of patients was 47.03 ± 19.7 with a male to female ratio of 1.2:1. Union was achieved in 57.89%; the rest underwent revision surgery. There was no significant association between outcomes after LIPUS treatment and patients' age, gender, smoking status or type of non-union. Patients with a small inter-fragment bone gap were more likely to have a successful outcome after LIPUS (p = 0.041). Time to treatment did not have a statistically significant impact on outcomes after LIPUS. Interestingly, all 6 patients with diabetes in the study managed to achieve union after LIPUS.

Conclusions: This study demonstrates that LIPUS is not successful in a large proportion of patients with established fracture non-unions. However, it does represent a low risk treatment modality as an alternative to revision surgery, especially for patients with diabetes who have a small inter - fragment bone gap. More research in the form of large randomised controlled trials needs to be carried out to further assess the role of LIPUS in the treatment of non-unions.

Keywords: Delayed union; Diabetes; Exogen; Fracture; Inter-fragment bone gap; Low intensity pulsed ultrasound; Non-union; Smoking.

Fig. 1

Inclusion and exclusion criteria for patients in our study. 6 patients who underwent LIPUS had missing serial radiographs and were therefore excluded from the study.

Fig. 2

Antero-posterior (AP) and lateral radiographs of the right femur of an adult male who was involved in a road traffic collision, taken at the time of presentation to hospital. The radiographs demonstrate a displaced mid-femoral shaft fracture which has been temporarily immobilised in a splint.

Fig. 3

AP and lateral radiographs taken immediately post-operatively after fixation of the right femoral shaft fracture with an intramedullary nail.

Fig. 4

AP and lateral radiographs taken 3 months post-operatively. The distal locking screws have broken, and the fracture remains non-united although there is callus formation at the fracture site.

Fig. 5

AP and lateral radiographs taken 3 months after starting LIPUS therapy. The amount of callus surrounding the fracture site has increased, with the fracture beginning to unite.

Fig. 6

AP and lateral radiographs taken 1 year after starting LIPUS therapy. The fracture appears to have united radiologically.