WO2012093181A1

WO2012093181A1 - System for measuring loads on forearm crutches

Info

Publication number: WO2012093181A1
Application number: PCT/ES2011/000340
Authority: WO
Inventors: Gema CHAMORRO MOLLINA
Original assignee: Universidad De Sevilla
Priority date: 2010-11-30
Filing date: 2011-11-30
Publication date: 2012-07-12
Also published as: ES2383412B1; ES2383412A1

Abstract

The invention relates to a system for measuring loads on forearm crutches, that is to say on crutches provided with a body (1) that can be adapted to the user's forearm, has a grip (2) and extends downwards as a long shaft (3), which finishes in an end piece (4) for supporting the crutch on the ground, characterized in that it incorporates, in line with the lower end of the shaft (3) and inside the latter, a charge cell (5) connected to the signal amplifier, data acquisition, radio and supply battery cards, the data acquisition card being provided with connections for both crutches and for an acoustic, visual and/or tactile warning system which is activated when the patient exceeds or does not reach the prescribed load range, and also when the crutches are not supported synchronously with the limb affected.

Description

SYSTEM OF MEASUREMENT OF LOADS IN ANTIBRAZE BOTTOMS

The present invention relates to a new system for measuring the loads that are supported by forearm canes, also called Canadian canes, in order to determine whether said loads are in practice adapted to the instructions given in this regard by a physiotherapist. The invention thus falls within the scope of physiotherapy equipment.

The object of the invention is, from a certain range of forces with which the cane must act on the ground, to provide the user with acoustic and / or visual information at the moment when said range is abandoned, both by excess and by default, so that the subject can become aware of his mistake and correct himself. In the same way, the system offers, in a complementary way, information on the coincidence of the loads exerted on the canes with the supports, and therefore discharges, of the affected lower limb. The measurement system also has the possibility of recording, analyzing and visualizing the data simultaneously with the execution of the patient on a PC.

STATE OF THE PREVIOUS TECHNIQUE

In functional recovery therapies with the participation of canes, it is essential to follow the instructions of the physiotherapist regarding the body load that, through the arms and canes, must be transmitted directly to the ground, discharging the lower extremities.

Many patients with musculoskeletal injuries of a lower limb, or surgically operated, require the use of canes to partially discharge their body weight. Functional reeducation of gait usually requires a progressive increase in load on the affected limb, which varies depending on the pathology and the individual conditions of the patient. As a general rule, both the doctor and the physiotherapist give verbal guidelines to the patient about the burdens they must perform, but it is known, after multiple investigations, which are hardly met, given the difficulty of the accuracy of these percentages. To this we must add that, sometimes, patients do not support and load the canes slightly before or synchronously to the supports and loads of the affected limbs, but erroneously, the cane contacts the ground after the foot is already supporting weight, thus performing an inefficient and dangerous assisted march for the subject. In addition, it should be borne in mind that, not only is the fact that it is a complicated action to be carried out and that it requires a learning process, but that the patient's ability and agility are essential for its achievement.

On the other hand, on many occasions physiotherapists observe that patients with partial discharge use a single cane, although this implies constant alterations in relation to a normal gait pattern, such as body misalignment, abnormal plantar supports, asymmetries in the steps, etc.

Therefore, a load measurement system is required that does not require large spatial resources or high technical knowledge for its use, and which in turn allows dynamic measurements of gait in different real situations, such as going down a step or going up a ramp.

Through the Patent DE 102004049551, a device consisting of a pressure sensor placed on the patient's foot that collects the loads is known and that thanks to a cable carries the information of the data to the patient through a screen or display located in the fist of the cane. When receiving visual information in the fist, it is understood that the patient must be in static standing position, since walking should not look down, and in addition, the display would also be in constant displacement along with the cane.

For its part, Patent FR 2638340 describes a system consisting of the use of strain gauges at the end of the cane rod, which allows controlling the amount of load exerted by the patient. This patent shows an acoustic warning system (bio-feedback) installed in the cane itself, which requires constant system calibrations, so it needs continuous technical maintenance, not being able to collect and analyze the data on a PC. .

It should also be noted Patent DE 10214745, in which a system is described in which the loads applied to the cane are analyzed by means of a sensor that measures the changes in length in the cane thereof. These changes will be related to the forces exerted on the cane, emitting excess signals, and without being able to collect and analyze the data. None of the aforementioned systems allows their use with one or two sticks interchangeably, so that comparisons between the advantages and disadvantages of the use of a cane or two in cases of partial discharge, with a percentage of specific body weight, cannot be made.

Finally, we highlight Patent P200901942, from which, important improvements reflected in the present invention have been made, considering this the closest antecedent to it. These mainly consist of adding, in a complementary way, a new biofeedback mechanism that allows to know the simultaneity of the support of the rods and the lower limb to be unloaded. If such synchronism did not occur, the patient would receive acoustic and / or visual information to later correct his wrong assisted walking. In addition, the electronic components have been improved, as well as the signal amplifiers incorporated into the control box that the patient carries in the belt, with the intention of reducing the weight of the rods and consequently facilitating their handling. A last novelty, but no less important, in relation to the mentioned patent, consists in the possibility of replacing the cables that go from the sensors to the control box with a wireless system, allowing the latter (in the form of a clock, mobile , search, etc.) is much more attractive and convenient to transport, this option being considered a second practical embodiment of the present invention.

EXPLANATION OF THE INVENTION

The system that the invention proposes, solves in a completely satisfactory way the problem previously exposed, so that it allows to record, analyze and visualize the load information in each cane independently, with which comparisons can be made between the use of one and two canes with the same amount of load, as well as the tendency to the greater load in a contralateral or ipsilateral cane. It also offers the patient the possibility of correcting their lack of precision on the prescribed loads, thanks to a biofeedback mechanism with acoustic or tactile and visual signals, when the requested weight range is exceeded or not reached. A second optional feedback mechanism that complements the measurement system is the one that informs the subject about the simultaneity between the supports of the rods and the support of the lower limb to be unloaded. To do this, more specifically, the load measurement system that the invention proposes is to provide each baton with a miniature prehensile load cell, placed at the end of the rod, thus limiting the errors caused by the moments of force exerted by the support and force applied by the hand and forearm simultaneously. Said load cell will allow a slight flexibility of the same to be able to measure the loads when the cane is not completely perpendicular to the ground, as occurs at the beginning and the end of each step. If the sensitivity range of the sensor is not sufficient, a dynamic coupling system will be installed that will correct said error margin.

In a first practical embodiment of the invention, the load cell is accompanied by a cable along the inside of the rod, which will be connected to a small signal amplifier, and this in turn to a data acquisition card and radiofrequency powered by a battery. The set of the aforementioned elements are integrated in a pouch-shaped control box placed on the back of the patient's belt, so as not to hinder or alter the gait.

In a second practical embodiment of the invention, the cables from the sensors to the control box are replaced by a wireless system, preferably by radiofrequency, such as Bluetooth® or equivalent, so that the load cells, the electronics and their batteries would be immersed inside the cane of each cane. The signals from the sensors are picked up by a much smaller control device in size and weight that no longer necessarily has to be placed on the back of the patient's belt to connect the wiring. The device could have various designs such as a watch, mobile or search among others, which could be placed on the wrist and / or arm, on the belt, etc. We can optionally add a data storage card to this control module.

By means of a wireless system independent of the mentioned one, the data arrives at a receiver with input to a PC through a USB port. The information is recorded, analyzed and visualized simultaneously to the execution of the subject, showing graphs of load behavior. This program allows the printing of external data, such as patient weight, so that information about loads can be received in percentages of body weight and thus facilitate comparative analysis of the sample and other previous studies. The data acquisition card that incorporates the control device that the patient carries, in addition to having connections for both canes, has other channels for the adaptation of complementary systems:

- Biofeedback mechanism I: that emits acoustic, visual, light and / or tactile signals (by means of vibrations in the handle), when the patient exceeds or does not reach the load range marked by the physiotherapist, and that has previously been introduced in the control module by means of the pulsometers and the digital display that allow modifying the parameters.

- Biofeedback Mechanism II: which provides information on the simultaneity of stick loads and supports and discharges of the affected limbs, by means of two transducers or sensors placed on the front and back of the sole of the patient's footwear, that mark the beginning and end of the foot support on the ground. The devices are protected by a semi-elastic material in the shape of a bowl (in the heel and toe), which are fixed and adjusted to the footwear by elastic straps with sailboat and straps. From the transducers or sensors part a cable to the control box, in mode I, by the back of the affected member, fixed and guided by a strap placed on the leg. In mode II, the data would reach the control device wirelessly, so the sensors must have the same as the poles of a transmitter with its own power. The support range will be graphically compared in the computer equipment with the beginning and end of the supports and loads of the sticks. Like the biofeedback mechanism I, it emits informative signals to the patient if he or she is not synchronously performing the supports.

In addition to the acoustic and / or tactile “biofeedback” warning or “warning” system that allows mobility to the patient without limiting the progress to the laboratory or treatment room, the incorporation of a visual feedback through a cannon is planned. issue the image of the large-scale physiotherapist / researcher's computer screen, so that the patient observes it while walking.

Throughout the description and the claims the word "comprises" and its variants are not intended to exclude other technical characteristics, additives, components or steps. For those skilled in the art, other objects, advantages and features of the invention will be derived partly from the description and partly from the practice of the invention. The following examples and drawings are provided by way of illustration, and are not intended to be limiting of the present invention. In addition, the present invention covers all possible combinations of particular and preferred embodiments indicated herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG 1. Schematically shows an individual carrying a forearm cane provided with the load measurement system of the invention, in a first practical embodiment, with cable connections, as well as the complementary data analysis equipment.

FIG 2. Schematically shows a detailed view of the fixation of the invention at the foot of the carrier individual.

FIG 3. Schematically shows an individual carrying a forearm cane provided with the load measurement system of the invention, in a first practical embodiment, with wireless connections, as well as the complementary data analysis equipment.

PREFERRED EMBODIMENT OF THE INVENTION

In a first embodiment of the invention, as shown in Figures 1 and 2, a forearm cane is represented, that is to say a cane (1) provided with means for adapting to the user's forearm, with a handle (2) and a reed (3) of appropriate length, topped by its lower end in a bead (4), and where the invention consists of installing inside the reed (3) and near its lower and free end, that is to say, next to the container (4), a load cell (5).

The load cell (5) is connected, through a cable (6) that runs inside the rod, with a control box (7), which integrates signal amplifiers, data acquisition and radio frequency cards, battery, etc. ., placed on the back of a belt (8) that the patient is given.

The aforementioned control box (7) transmits the data received from the load cell (5) to a receiver (9), also wireless, with a USB port for data recording, analysis and simultaneous visualization of the same in a PC (10).

In addition, the control box (7) is also associated with a system of warning, that is to say a biofeedback system, acoustic, visual and / or tactile, that allows mobility to the patient without limiting it to the laboratory or treatment room, and that by means of vibrations in the handle of the cane or by any other means , generate warning signals to the patient when the patient exceeds or does not reach the load range marked by the physician's prescription. Similarly, a second biofeedback mechanism composed of a transducer or sensor in the forefoot (11) and another in the rearfoot (12), is connected to the data acquisition card integrated in the control box (7).

Returning again to the connection between the load cell (5) and the control box (7), the said cable (6) that runs through the cane, leaves said rod substantially in correspondence with the upper extremity thereof, from where said cable (6) is kept in the air and duly oversized to reach the flask (7), without said cable (6) being the least obstacle to the normal movement of the user's body, as well as of the rods themselves.

The fixation of the forefoot transducer (11) and the rearfoot transducer (12) to the anterior and posterior ends, respectively, of the sole of the footwear, is solved by means of semi-elastic protective cups (13) with adjustable fasteners, starting from these devices, a cable (14) that ascends through the back of the lower limb, guided and held by a strap (15) placed on the patient's leg, until connected to the control box (7).

A second practical embodiment is shown in Figure 3, a forearm cane is represented, that is to say a cane (1) provided with adaptation means to the user's forearm, with a handle (2) and a rod (3) in length appropriate, topped by its lower end in a bead (4), and the invention consists in installing inside the reed (3) and near its lower and free end, that is to say next to the bead (4), a cell loading (5).

The load cell (5) is related to the corresponding electronics (26), batteries (27) that give it autonomy and a wireless system (28) that sends the data to the control device (29). In turn, the fixation of the forefoot transducer or sensor (11) and the rearfoot transducer or sensor (12) to the front and rear ends, respectively, of the sole of the footwear, is resolved by protective cups

(13) semi-elastic with adjustable fixings, starting from these devices, a cable

(14) that connects to a wireless transmitter (25) with its corresponding power (21), fixed to the ankle or foot of the subject by means of a strap (22), which will send the data to the control device (29). In addition, according to the need of the physiotherapist and / or researcher, the data can also be sent to a computer (24) wirelessly, being collected by a receiver (23) connected via a USB port.

Claims

I ^a .- Load measurement system in forearm canes, that is, in canes equipped with a body (1) adaptable to the user's forearm, with a handle (2) and extended inferiorly in a long rod (3) finished off in a support (4) support on the ground, characterized in that in correspondence with the lower end of the rod (3) and inside it incorporates a load cell (5) connected to the signal amplifier, acquisition cards of data and radio and battery of feeding, being the card of acquisition of data provided of connections for both sticks and for a system of acoustic, visual and tactile warning, that is activated when the patient exceeds or does not reach the prescribed load range , as well as to a feedback mechanism that informs of the simultaneity between the support of the canes and that of the affected member, data acquisition card associated in addition to a wireless transmitter that transmits the information extracted by the load cell (5) to a similarly wireless receiver (9.23), with connection body for recording, analysis and visualization of the received data, in a computer equipment (10,24).

2 .- system load measuring sticks forearm, according to claim 1, wherein the data acquisition card and signal amplifier is integrated in a control box (7) shaped pouch that is attached to the waist of the user through a belt (8), said control box (7) being connected to the load cell (5) by means of a cable (6) that runs through the hollow interior of the cane rod (3), to emerge from the outside through the free limb of the same, leaving a sector long enough to not interfere with the patient's body movement or the movement of the complementary cane.

3 .- system load measuring sticks forearm, according to claim 1 wherein the load cell (5) is associated with the corresponding electronics (26), batteries (27) that give autonomy and a wireless system ( 28) that sends the data to a control device (29).

4 .- system load measuring sticks forearm, according ^to claim 3 characterized in that it comprises control means in the affected member wherein fixing the transducer or sensor forefoot (11) and the transducer or sensor rearfoot (12 ) to the front and rear ends, respectively, of the sole of the footwear, it is resolved by means of semi-elastic protective cups (13) with adjustable fixings, starting from these devices, a cable (14) that connects to a Wireless transmitter (25) with its corresponding power supply (25), fixed to the ankle or foot of the subject by means of a strap (22), which will send the data to the control device (29).

5 .- system load measuring sticks forearm, according ^to claim 2 comprising control means in the affected wherein the transducer mounting member the forefoot (11) and rearfoot transducer (12) to the ends front and back, respectively, of the sole of the footwear, is resolved by means of semi-elastic protective cups (13) with adjustable fixings, starting from these devices, a cable (14) that ascends through the back of the lower limb, guided and held by a webbing (15) placed on the patient's leg, until connected to the control box (7).

6 ^a. - System of measurement of loads in forearm sticks, according to claims 1, 3 and 4 characterized in that, according to the need of the physiotherapist and / or researcher, the data can also be sent to a computer equipment (24) of wirelessly, being picked up by a receiver (23) connected through a USB port.