The assessment of bone healing in radiographs typically relies on the volume and radio-opacity of callus at the healing site. However, this method is not entirely objective, leading to variability among observers. To address this challenge, a clinical system utilizing the echo tracking (ET) method has been developed, providing a quantitative approach akin to a three-point bending test for the evaluation of healing fractures, specifically of the tibia.
Purpose of the Study
This study aims to validate the ET system as a clinical tool to assess the progression, delay, or arrest of bone healing. It focuses on the practical application of this technology in a clinical setting, ensuring a versatile, quantitative, and noninvasive assessment technique.
Methodology
During the assessment, the fibular head and the lateral malleolus were supported, and a 7.5-MHz ultrasound probe was positioned on the proximal and distal fragments of the tibia. A standard load of 25 N was applied. The procedure involved setting five tracking points along the long axis of the ultrasound probe at 10 mm intervals. Utilizing a multiple ET system, two probes simultaneously measured the displacement of these tracking points on each fragment, enabling the detection of fragment bending induced by the applied load. The ET angle, defined as the sum of inclinations of the proximal and distal fragments, served as the primary metric for assessment.
Clinical Findings
The study monitored eight tibial fractures in seven patients, treated either by casting or internal fixation. Results showed that in cases of normal healing, the bending angle decreased exponentially over time, indicating successful recovery. Conversely, in cases of nonunion, the bending angle remained constant, signaling delayed or arrested healing. These findings underscore the ET method's potential as a clinically applicable, versatile, and noninvasive technique to evaluate fracture healing.
Conclusion
The introduction of the echo tracking method offers a significant advancement in the noninvasive assessment of bone healing. By providing a quantitative measure of fracture recovery, the ET method represents a valuable tool for clinicians in the monitoring and management of tibial fractures.
