A fracture healing monitoring device and method based on the principle of hand-transmitted vibration

Abstract

The present invention provides a fracture healing monitoring device based on the principle of hand-transmitted vibration, comprising: an external transmission device, including an acceleration sensor, a band, a vibration signal output platform, a force sensor, and a vibration table; the acceleration sensor is fixed to the proximal end and the distal end of the fracture site through the band, and the force sensor is arranged between the vibration table and the vibration signal output platform for collecting the normal pressure applied by the patient on the vibration table; the vibration table vibrates with a predetermined random vibration signal; the fracture acting end presses on the vibration signal output platform with a certain pressure, and the direction of the pressing force is parallel to the direction of the vibration signal; a signal acquisition and analysis module, which acquires the data collected by each sensor, obtains the system resonance frequency and the root mean square value of the signal, and judges the fracture healing situation. The device of the present invention can long-term monitor the axial dynamic performance of the fracture system with a non-invasive and non-radiative device, and the collaborative analysis of the two parameters can improve the accuracy of judging the fracture healing state.

Description

Technical Field

[0001] The present invention relates to the field of fracture healing assessment, and particularly to a fracture healing monitoring device and method based on the principle of hand-transmitted vibration. Background Art

[0002] In daily work and life, people are inevitably involved in fracture accidents. Traditional treatment methods include direct restoration and indirect restoration. Indirect restoration makes use of technologies such as implanting orthopedic medical devices or external fixation brackets. During the fracture healing process, since the patient needs to perform rehabilitation activities, remove the implanted materials or disassemble the external fixation bracket. Therefore, it is necessary to monitor the healing status of the fracture, and the monitoring of the axial dynamic characteristics of the fracture-related system can be an important reference basis for the above operations. Among them, the vibration mode of the skeletal system is an important parameter. Each substance in nature has its resonance frequency, and the fracture system also has its resonance frequency. As the callus differentiates, proliferates, and mineralizes, the resonance frequency of the system will continuously increase, and at the same time, the overall biomechanical performance of the fracture system will improve. According to the relevant theoretical knowledge of modal analysis, the resonance frequency of the system depends on the ratio of system stiffness to mass. During the fracture healing process, as the callus tissue differentiates, proliferates, and mineralizes, in the initial stage of healing, the diameter of the callus will increase rapidly. The geometric size of the callus is relatively small compared to the skeletal system, and the callus, as a soft tissue, has a much lower density than bone tissue. Therefore, the increase in callus mass has a limited impact on the system resonance frequency, but the significant increase in system stiffness will significantly affect the resonance frequency. The change in the system mode will also affect the response of the system to external vibration excitation.

[0003] Currently, various commonly used medical imaging methods such as CT, MRI, and ultrasound can only establish a visual judgment on the healing status of the fracture, cannot measure the axial dynamic characteristics of the fracture system, and cannot generate a clear status judgment in the initial stage of fracture healing. Summary of the Invention

[0004] The main object of the present invention is to overcome the above-mentioned defects in the prior art, and propose a device that can non-invasively and non-radiatively monitor the axial dynamic performance of the fracture system for a long time, and the collaborative analysis of two parameters can improve the accuracy of determining the fracture healing status.

[0005] The present invention adopts the following technical solutions:

[0006] A fracture healing monitoring device based on the principle of hand-transmitted vibration, comprising:

[0007] An external transmission device, comprising an acceleration sensor, a band, a vibration signal output platform, a force sensor, and a vibration table; the acceleration sensor is fixed to the proximal end and the distal end of the fracture site through the band, and the force sensor is arranged between the vibration table and the vibration signal output platform for collecting the positive pressure exerted by the patient on the vibration table; the vibration table vibrates with a predetermined random vibration signal; the fracture acting end presses on the vibration signal output platform with a certain pressure, and the direction of the pressing force is parallel to the direction of the vibration signal;

[0008] A signal acquisition and analysis module, which acquires the data collected by each sensor, obtains the system resonance frequency and the root mean square value of the signal, and judges the fracture healing condition.

[0009] Specifically, the acceleration sensor is fixed to the proximal end and the distal end of the fracture site through the band, specifically:

[0010] The acceleration sensor is fixed to the proximal end and the distal end of the fracture site through the band, and is respectively used for collecting the time-domain signals g yy (t) and g xx (t) of the acceleration along the bone axis at two positions during the test.

[0011] Specifically, the fracture acting end presses on the vibration signal output platform with a certain pressure, and the certain pressure is 25N - 55N.

[0012] Specifically, the vibration table vibrates with a predetermined random vibration signal, and the vibration frequency range is 1 - 1600Hz.

[0013] An embodiment of the present invention further provides a fracture healing monitoring method based on the principle of hand-transmitted vibration, comprising:

[0014] Fix the acceleration sensor to the proximal end and the distal end of the fracture site through the band, and respectively use it to collect the time-domain signals g yy (t) and g xx (t) of the acceleration along the bone axis at two positions during the test;

[0015] The fracture acting end presses on the vibration signal output platform with a certain pressure, and the direction of the pressing force is parallel to the direction of the vibration signal, and the force sensor collects and determines the positive pressure exerted by the patient on the vibration table;

[0016] The vibration table vibrates with a predetermined random vibration signal;

[0017] The acceleration sensor collects the acceleration signal g xx (t) input from the distal end of the fracture site and the vibration signal g yy (t) output from the proximal end; calculate the system resonance frequency and the root mean square value of the signal according to the acceleration signal, and judge the fracture healing condition.

[0018] Specifically, it includes calculating the resonance frequency and root mean square value of the fracture system based on the acceleration signal input at the distal end of the fracture site and the acceleration signal output at the proximal end of the fracture system. Specifically:

[0019]

[0020]

[0021] Where g(τ) is the time-domain signal of acceleration, specifically the acceleration signal g xx (t) input at the distal end and the vibration signal g yy (t) output at the proximal end. The power spectral density S xx (e jw ) and S yy (e jw ) of the input and output signals of the fracture system are used to analyze the frequency response function of the dynamic characteristics of the fracture system, which is calculated by the following formula, where

[0022] S yy (e jw ) = |H(e jw )| 2 S xx (e jw )

[0023] Where S yy (e jw ) is the power spectral density of the vibration signal output from the proximal end of the fracture site, S xx (e jw ) is the power spectral density of the vibration signal input from the shaker to the distal end of the fracture site, and H(e jw ) is the frequency response function of the fracture system; where W = 2πf, f is the frequency, and the unit is Hz;

[0024] The root mean square value of the signal is calculated by the following formula

[0025]

[0026] Where G i 2 is the amplitude of the i-th discrete output vibration signal g yy (t) in the time domain collected by the signal acquisition system, with the unit of g, i = 1, 2, 3...n, and n is the number of vibration signals.

[0027] From the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The fracture healing monitoring device based on the principle of hand-transmitted vibration provided by the present invention can long-term monitor the axial dynamic performance of the fracture system in a non-invasive and non-radiative manner;

[0029] (2) The fracture healing monitoring device based on the principle of hand-transmitted vibration provided by the present invention uses the system resonance frequency and root mean square value parameters for collaborative analysis, which can further improve the accuracy of fracture healing state determination. Description of the Drawings

[0030] Figure 1 is a mechanical schematic diagram of the fracture healing monitoring device based on the principle of hand-transmitted vibration provided by an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of the power spectral density of the vibration test signal provided by an embodiment of the present invention;

[0032] Figure 3 is a structural diagram of the fracture healing monitoring device based on the principle of hand-transmitted vibration provided by an embodiment of the present invention.

[0033] Wherein, 1 - fracture acting end (taking the arm as an example), 2 - acceleration sensor, 3 - strap, 4 - vibration signal output platform, 5 - force sensor, 6 - vibration table, 7 - data acquisition system, 8 - data processing and analysis;

[0034] The following further details the present invention in conjunction with the drawings and specific embodiments. Specific Embodiments

[0035] Vibration can be represented by displacement, velocity, and acceleration in the time domain. However, when analyzing the dynamic vibration characteristics of a system, the acceleration of vibration can cover the vibration energy distribution information, and the acceleration can be obtained by differentiating the displacement and velocity curves. The acceleration signal is easy to collect. Therefore, the acceleration of the vibration signal is selected as the original data when analyzing the vibration in the method of the present invention.

[0036] Please refer to Figure 1, A mechanical schematic diagram of a multi-parameter fracture healing monitoring device based on the principle of hand-transmitted vibration. The mechanical structure part of this method includes a fracture acting end (taking the arm as an example) 1, an acceleration sensor 2, a strap 3, a vibration signal output platform 4, a force sensor 5, and a vibration table 6. The vibration signal output platform 4 is connected to the vibration table 6 through the force sensor 5 to collect the normal pressure exerted by the patient on the vibration table during the fracture healing monitoring process. During the monitoring process of the fracture acting end (taking the arm as an example) 1, to ensure the repeatability of monitoring and the comparability of data, it is recommended to apply a normal pressure of 30 ± 5 N to 50 ± 5 N (relative standard deviation of data < 8%) on the surface of the vibration signal output platform 4, and it is necessary to ensure that the direction of the applied force is parallel to the direction of the vibration signal. A certain pressure is to ensure the stability and comparability of the data. The strap 3 is used to press the acceleration sensor 2 on the limb surface near the proximal and distal ends of the fracture site with a certain pre-pressure to reduce the influence of human soft tissue damping on the transmission and acquisition of vibration signals.

[0037] Please refer to Figure 2 and Figure 3 , Figure 2 The curve in

[0038] is the power spectral density spectrogram of the random vibration test signal set based on the principle of hand-transmitted vibration. A predetermined random vibration signal is set in the control system of the vibration table 6 to perform the vibration test on the fracture system. The data collected by the acceleration sensor is collected by the data acquisition system 7, and the comparison of the dynamic characteristics of the fracture system at different healing stages is obtained during the data processing and analysis 8, thereby completing the monitoring of fracture healing. yy (t) and g xx (t), and the preset random vibration signal can be adjusted in terms of signal amplitude and frequency spectrum according to the actual situation of the patient. 3. The acquisition of the system resonance frequency and the root mean square value (RMS) of the output signal and the related collaborative analysis can effectively obtain the fracture healing status at each stage.

[0039] Among them, according to the acceleration signal g xx (t) input from the distal end of the fracture site and the acceleration signal g yy (t) output from the proximal end of the fracture system, the resonance frequency of the fracture system is calculated. The resonance frequency of the system can first calculate the power spectral density (PSD) of the vibration signals measured by each sensor, as shown in the following formula

[0040]

[0041] Where

[0042]

[0043] Where g(τ) is the time-domain signal of acceleration, specifically the acceleration signal g xx (t) input from the distal end and the vibration signal g yy (t) output from the proximal end. The power spectral densities S xx (e jw ) and S yy (e jw ) of the input and output signals of the fracture system are used to analyze the frequency response function of the dynamic characteristics of the fracture system, which is calculated by the following formula. Where

[0044] S yy (e jw ) = |H(e jw )| 2 S xx (e jw )

[0045] Where S yy (e jw ) is the power spectral density of the vibration signal output from the proximal end of the fracture site, S xx (e jw ) is the power spectral density of the vibration signal input from the shaker to the distal end of the fracture site, and H(e jw ) is the frequency response function of the fracture system; where w = 2πf and f is the frequency, with the unit of Hz. The corresponding resonance frequency of the system can be obtained by analyzing its frequency response function.

[0046] The root mean square value (RMS) of the signal is calculated by the following formula

[0047]

[0048] Where G i 2 is the i-th discrete output vibration signal g yyThe amplitude of (t), in g units, where i = 1, 2, 3... n and n is the number of vibration signals.

[0049] Finally, the variance analysis of the resonance frequency and root mean square value of the system collected at different healing stages is performed to judge the fracture healing condition.

[0050] The above is only the specific implementation manner of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantive modification of the present invention using this concept shall fall within the scope of infringement of the protection scope of the present invention.

Claims

1. A fracture healing monitoring device based on the principle of hand-transmitted vibration, characterized in that, comprising: An external transmission device, comprising an acceleration sensor, a band, a vibration signal output platform, a force sensor, and a vibration table; the acceleration sensor is fixed to the proximal end and the distal end of the fracture site through the band; specifically: the acceleration sensor is fixed to the proximal end and the distal end of the fracture site through the band, and is respectively used to collect the time-domain signals g yy (t) and g xx (t); A force sensor is arranged between the vibration table and the vibration signal output platform for collecting the positive pressure exerted by the patient on the vibration table; a vibration table that vibrates with a predetermined random vibration signal; a fracture acting end presses on the vibration signal output platform with a certain pressure, and the direction of the pressing force is parallel to the direction of the vibration signal; A signal acquisition and analysis module, which acquires the data collected by each sensor, obtains the system resonance frequency and the root mean square value of the signal, and judges the fracture healing condition; The signal acquisition and analysis module calculates the fracture system resonance frequency and the root mean square value of the signal according to the acceleration signal input at the distal end of the fracture site and the acceleration signal output at the proximal end of the fracture system. Specifically: where \(g(\tau)\) is the time-domain signal of acceleration, specifically the acceleration signal \(g_{in}(t)\) input at the telecentric end and the acceleration signal \(g_{out}(t)\) output at the centripetal end. The power spectral densities \(S_{in}(e^{j\omega})\) and \(S_{out}(e^{j\omega})\) of the input and output signals of the fracture system are calculated from the above formula and are used to analyze the frequency response function of the dynamic characteristics of the fracture system, which is calculated from the following formula, where xx (t) and the acceleration signal \(g_{out}\) yy (t) at the centripetal end output. The power spectral densities \(S_{in}(e^{j\omega})\) and \(S_{out}(e^{j\omega})\) of the input and output signals of the fracture system are calculated from the above formula and are used to analyze the frequency response function of the dynamic characteristics of the fracture system, which is calculated from the following formula, where xx (e^{j\omega}) and \(S_{out}\) jw (e^{j\omega}) are used to analyze the frequency response function of the dynamic characteristics of the fracture system and are calculated from the following formula, where yy (e^{j\omega}) are used to analyze the frequency response function of the dynamic characteristics of the fracture system and are calculated from the following formula, where jw (e^{j\omega}) are used to analyze the frequency response function of the dynamic characteristics of the fracture system and are calculated from the following formula, where S yy (e jw ) = |H(e jw )| 2 S xx (e jw ) Among which S yy (e jw ) is the power spectral density of the vibration signal output from the proximal end of the fracture site, and S xx (e jw ) is the power spectral density of the vibration signal input by the shaker to the distal end of the fracture site, and H(e jw ) is the frequency response function of the fracture system; where w = 2πf, f is the frequency, and the unit is Hz; The root mean square value of the signal is calculated by the following formula Among which G i 2 is the amplitude of the ith discrete output acceleration signal g(t) in the time domain collected by the signal acquisition system, with the unit of g, where i = 1, 2, 3... n and n is the number of vibration signals. yy (t), with the unit of g, i = 1, 2, 3... n, and n is the number of vibration signals.

2. The fracture healing monitoring device based on the principle of hand-transmitted vibration according to claim 1, characterized in that, The fracture acting end presses on the vibration signal output platform with a certain pressure, and the certain pressure is 25N - 55N.

3. The fracture healing monitoring device based on the principle of hand-transmitted vibration according to claim 1, characterized in that, The vibration table vibrates with a predetermined random vibration signal, and the vibration frequency range is 1 - 1600Hz.

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