Abstract
Objective
To determine what factors affect fracture healing with low-intensity pulsed ultrasound (LIPUS) for delayed unions and nonunions.
Patients
A consecutive cohort of 101 delayed unions and 50 nonunions after long bone fractures treated with LIPUS between May 1998 and April 2007.
Main Outcome and Measurements
Radiographic determination of osseous bone union within one year after start of LIPUS therapy. Recognition of predictable factors that affect treatment results of LIPUS.
Main Results
1) Delayed union group (n=101): Seventy-five delayed union (74.3%) united without an additional major surgical intervention. Failure of LIPUS therapy was associated with types of nonunion (atrophic vs. hypertrophic, RR 23.72 [95%CI: 1.20–11.5], p<0.01), instability at fracture site (unstable vs. stable, RR 3.03 [1.67–5.49], p<0.001), and maximum fracture gap size not less than 9 mm (RR 3.30 [1.68–6.45]).
2) Nonunion group (n=50): Thirty-four nonunions (68.0%) united without an additional major surgical intervention. Failure of LIPUS therapy was associated with method of fixation (IM nail vs. others, RR 4.50 [95%CI: 1.69–12.00], p<0.001), instability at fracture site (unstable vs. stable, RR 4.56 [2.20–9.43], p<0.0001), and maximum fracture gap size not less than 8 mm (RR 5.09 [1.65–15.67]).
Conclusions
LIPUS should be applied as an adjuvant therapy in combination with surgical intervention for an established atrophic nonunion with instability and/or with larger fracture gap.
