PAPER 37 PREDICTABLE FACTORS WHICH AFFECT TREATMENT RESULT OF A LOW-INTENSITY PULSED ULTRASOUND (LIPUS) FOR DELAYED AND NON-UNIONS

Abstract

Background: Low-intensity pulsed ultrasound (LIPUS) was shown to accelerate fracture healing with delayed unions and non-unions as well as fresh fractures.

Objective: To know the factors which affected clinical results of LIPUS treatment for delayed unions and non-unions.

Design: Prospective Cohort Study

Setting: University Hospital

Intervention: 192 delayed or non-unions of long bone or clavicle were treated by LIPUS from May 1998 to April 2007. Background factors (age and gender of patient, history of smoking, personality of each fracture, intervals from injury to application of LIPUS treatment) were prospectively investigated. All patients were followed up at the outpatient clinic and AP and lateral view of radiographs were taken usually every 4 weeks. Main outcome of this study was set as “bone union” and it was defined as cortical continuity in a minimum of three cortices on two views on radiographs and without pain at the fracture site on palpation.

Main Outcome Measurement: The overall success rate was 75%, and the success rate of subcutaneous bones were higher (tibia: 81%, radius and ulna: 80%)than that of deeper bone (femur: 64%, humerus 58%). Logistic multi-variant regression showed that the greatest gap size between the main bone fragments (p< 0.0001), instability of a fracture site (p< 0.0001), and the intervals between injury to the application of LIPUS (p< 0.05) were independent predictors for the success of LIPUS treatment for delayed and non-unions.

Conclusion: We believe that the greatest gap size of main fragments, instability of a fracture site, and the age of non-union are the factors that affected LIPUS clinical results.