Clinical Applications of Biophysical Stimuli Technologies for Bone Healing

Bone healing is a complex physiological process modulated by coordinated biological and mechanical factors. Despite bone's inherent regenerative capabilities, approximately 5-10% of fractures experience delayed union or nonunion, often attributed to factors such as infection, mechanical instability, poor vascularization, or systemic conditions like diabetes and osteoporosis. Thus, targeted interventions are essential to counteract these disruptions and improve bone healing outcomes. This review examines the existing literature on biophysical stimuli technologies based on electrical, ultrasound, piezoelectric and vibrational stimulations, engineered to promote bone healing. Furthermore, a summary of the technologies and their mechanism of action is provided along with the clinical applications, advantages, limitations, and challenges associated with these emerging technologies. Overall, these biophysical stimuli technologies have the potential to be an effective adjunct to standard treatment approaches to accelerate healing. Among them, electrical stimulation and low-intensity pulsed ultrasound are the most clinically mature biophysical modalities with demonstrated efficacy in delayed union and nonunion fractures, whereas piezoelectric and vibrational technologies remain largely at the preclinical or early translational stage but show emerging potential for adjunctive bone healing therapies. However, translating findings from in vitro experiments and small animal models into successful clinical applications remains difficult. To advance clinical adoption of these biophysical stimuli technologies, future research should prioritize standardized input and output parameters, conduct direct comparisons using uniform metrics, and further explore the effects of combining these technologies. Studies must also evaluate cost, effectiveness, patient compliance, safety standards, and clearance requirements for medical device translation. Furthermore, technologies that require no or minimal changes to existing surgical techniques will further facilitate regulatory approval and surgeon adoption.