In silico re-foundation of strain-based healing assessment of fractures treated with an external fixator

Wireless Measurements Using Electrical Impedance Spectroscopy to Monitor Fracture Healing

There is an unmet need for improved, clinically relevant methods to longitudinally quantify bone healing during fracture care. Here we develop a smart bone plate to wirelessly monitor healing utilizing electrical impedance spectroscopy (EIS) to provide real-time data on tissue composition within the fracture callus. To validate our technology, we created a 1-mm rabbit tibial defect and fixed the bone with a standard veterinary plate modified with a custom-designed housing that included two impedance sensors capable of wireless transmission. Impedance magnitude and phase measurements were transmitted every 48 h for up to 10 weeks. Bone healing was assessed by X-ray, µCT, and histology. Our results indicated the sensors successfully incorporated into the fracture callus and did not impede repair. Electrical impedance, resistance, and reactance increased steadily from weeks 3 to 7-corresponding to the transition from hematoma to cartilage to bone within the fracture gap-then plateaued as the bone began to consolidate. These three electrical readings significantly correlated with traditional measurements of bone healing and successfully distinguished between union and not-healed fractures, with the strongest relationship found with impedance magnitude. These results suggest that our EIS smart bone plate can provide continuous and highly sensitive quantitative tissue measurements throughout the course of fracture healing to better guide personalized clinical care.

A Novel Capacitive Measurement Device for Longitudinal Monitoring of Bone Fracture Healing

The healing process of surgically-stabilised long bone fractures depends on two main factors: (a) the assessment of implant stability, and (b) the knowledge of bone callus stiffness. Currently, X-rays are the main diagnostic tool used for the assessment of bone fractures. However, they are considered unsafe, and the interpretation of the clinical results is highly subjective, depending on the clinician’s experience. Hence, there is the need for objective, non-invasive and repeatable methods to allow a longitudinal assessment of implant stability and bone callus stiffness. In this work, we propose a compact and scalable system, based on capacitive sensor technology, able to measure, quantitatively, the relative pins displacements in bone fractures treated with external fixators. The measurement device proved to be easily integrable with the external fixator pins. Smart arrangements of the sensor units were exploited to discriminate relative movements of the external pins in the 3D space with a resolution of 0.5 mm and 0.5°. The proposed capacitive technology was able to detect all of the expected movements of the external pins in the 3D space, providing information on implant stability and bone callus stiffness.

Mathematical Analysis of Application of a Three-Dimensional Printing Fixator in the Fracture of Multiple Ribs

Data were obtained from 66 clinical patients. The patients were divided into a non-3D printing group (control group) and a 3D printing group (intervention group) in a 1 : 1 ratio, with 33 patients in each group. The information including gender, age, incision length, number of surgical roots, bleeding volume, operation time, and intraoperative blood transfusion was collected for SPSS analysis. The results showed the following: (1) The paired t-test was used to test the difference of experimental data. There was a significant difference of 0.01 between the incision length/surgical root number in the intervention group and the incision length/surgical root number in the control group. The incision length/surgical root number in the intervention group was significantly lower than that in the control group. (2) Surgical time, intraoperative blood transfusion, age, and incision length/surgical root number in the intervention group had a significant positive impact on the amount of bleeding. Gender did not affect the amount of bleeding. (3) A total of 1 item of operation time in the intervention group had a significant positive impact on intraoperative blood transfusion. (4) The incision length/number of surgical roots in the intervention group had a noteworthy negative impact on blood transfusion during the operation.