From episodic imaging to real-time sensor monitoring: translational advances in assessing fracture healing dynamics

Fracture healing culminates in restoration of mechanical competence, yet clinical monitoring remains largely dependent on episodic imaging and subjective assessment, which provide delayed structural information and limited insight into the evolving stability of the fracture construct, contributing to uncertainty in clinical decision-making and delayed recognition of impaired healing. Advances in bioelectronics, implantable sensors, and wearable systems are enabling longitudinal assessment of fracture recovery by capturing quantitative signals related to mechanical load transfer, local tissue state, and functional activity in real-world settings. In this review, we synthesize recent developments in sensor-based fracture monitoring and propose a conceptual framework that integrates three complementary dimensions of healing assessment: mechanical competence, biological progression, and functional recovery. Among these, load-path sensing of implant-bone load transfer provides the most direct proxy for fracture stiffness and currently represents the most translationally mature approach, supported by emerging preclinical and early clinical studies. In contrast, biological sensing strategies, including impedance- and dielectric-based approaches, aim to detect earlier changes in callus composition but remain at lower levels of translational readiness, while wearable monitoring technologies offer scalable insights into rehabilitation trajectories but provide indirect measures of fracture stability. Collectively, these approaches support a transition from episodic structural imaging toward continuous, data-driven characterization of healing dynamics. Achieving clinical implementation will require workflow-integrated sensing systems, interpretable analytical frameworks linking sensor outputs to clinically actionable endpoints, and multicentre validation establishing standardized thresholds across fracture types and treatment strategies.

Current literature on fracture healing monitoring is largely technology-centric, with limited integration of sensing outputs into clinically actionable frameworks. This review addresses that gap by providing a unified, decision-oriented synthesis that links mechanical, biological, and functional sensing paradigms to the core clinical endpoint of fracture healing, restoration of mechanical competence, and to key management decisions such as weight-bearing progression, follow-up intensity, and early detection of delayed union. By contextualizing existing technologies within a translational maturity (TRL) framework and evaluating evidence from benchtop, preclinical, and early human studies, this work identifies which sensing strategies are closest to clinical implementation and what barriers remain, including the need for standardized protocols, validated decision thresholds, workflow integration, and scalable data interpretation. The translational value of this review lies in defining how continuous, quantitative monitoring can complement or partially replace episodic imaging, enabling earlier, more objective, and individualized fracture care, while providing a roadmap for the development, validation, and clinical adoption of sensor-enabled, data-driven orthopaedic management systems.