II–3 Compliance and the Bone Fusion Rate of Low-Intensity Pulsed Ultrasound (LIPUS) Treatment

Objective: The aim of this study is to clarify the necessity of the compliance (usage) rate to succeed bone union by LIPUS treatment device in the long bone fracture and the clavicular fracture. Materials and Methods: The subjects are 229 cases who were treated with the LIPUS device whose utilization rate was known after the surgical operation for fresh fractures, from 2008 to 2017. We have defined the LIPUS compliance rate (Number of days during which LIPUS was actually used/Number of days during which LIPUS was rented × 100). We have evaluated that LIPUS compliance rate. In a retrospective cohort study, outcomes were obtained that bone union was succeeded by LIPUS treatment alone. We investigated the compliance rate of LIPUS therapy equipment, conducted χ2 test of univariate analysis, and conducted Receiver Operator Characteristic (ROC) analysis on how much should be used. Results: Two hundred twenty-one Bones (96.5%) were bone union with LIPUS alone but 8 bones (3.5%) needed additional medical surgery. The average of compliance rate for LIPUS therapy was 75.9%. In the case of low compliance of LIPUS usage, there were failures of LIPUS treatment which is significant (P < 0.01). The cutoff value of the compliance rate in the ROC analysis was 57.1% (sensitivity 79.2%, specificity 75%, AUC [Area Under the Curve] = 0.779), for significantly difference in bone fusion ratio. Conclusion: The compliance (usage) rate of LIPUS treatment must be at least 60% to expect effective bone union.