RO138295A0 - Prosthetic system for detection and compensation of the length difference between human lower limbs - Google Patents

Abstract

The invention relates to a prosthetic system for detection and compensation of the length difference between human lower limbs in growing patients, to be applied in the field of recuperative medicine and prosthetics. According to the invention, the system consists of a self-adaptive prosthesis (1) attached to the stump (4) of a unilaterally amputee and a digital system (6) that takes pictures which are processed by a dedicated software in view of quick automatic detection of the length difference between the lower limbs of the amputee, using control elements (8) positioned on the amputee and other control elements (9) positioned on a flat surface behind the amputee and, based on the biomechanical data obtained thereby, a microcontroller (12) controls the lengthening or compression of the self-adaptive prosthesis, in order to equalize the limbs lengths in correlation with the automatically detected data, without requiring the intervention of a specialist, of the amputee or of an accompanying person.

Description

PROSTHETIC SYSTEM FOR DETECTION AND COMPENSATION OF THE LENGTH DIFFERENCE OF HUMAN LOWER LIMBS

The invention relates to a prosthetic system for the detection and compensation of the difference in length of human lower limbs, used in the case of patients with lower limb prostheses and growing, with applicability in the field of recuperative medicine and prosthetics, capable of detecting and compensating automatic human lower limb length difference device intended for the faithful replacement of the lost biological limb.

Several methods are known for determining limb length difference, such as direct limb measurement with a calibrated tape measure, blocks or objects of known size placed under the shorter limb or under the prosthesis, to level the pelvis using a special device in this sense, but also imaging methods, such as: simple radiography, orthoroentgenography, scanography, etc. [1, 2].

Electronic devices for determining the difference in limb length are also known which consist of the use of platforms equipped with sensors and on which the patient places each foot, some also containing sensors placed at the level of the pelvis, including devices that use plantar analysis in this sense [ 3-6],

These devices and methods present a number of disadvantages, related to:

- the adjustments to equalize the length of the artificial limb with the contralateral biological one are performed manually (passively), by a specialist, during the initial fitting of the prosthesis, with inaccurate measurement methods and instruments that do not ensure repeatability and traceability of the entire process;

the lack of tools necessary to carry out independent adjustments simultaneously with the growth rate, which causes asymmetries in the walking kinematics, changing the physiological position of the center of gravity of the body of the prosthesis wearer and causing chain pathologies at the level of healthy joints, the spine and at the level of the prosthesis;

RO 138295 AO

- the need for the permanent presence of a medical specialist capable of constantly adjusting the length of the prosthesis;

- the biomechanical imbalances caused by the difference in the length of the limbs which are most often visible and which make it difficult for the social and professional reintegration of the patient;

the permanent need to update the length of the prostheses during the growth period to use an identical, or at least similar, size to that of the biological contralateral limb;

- the regular, sometimes cumbersome movement of the amputee patient to the specialist capable of adjusting the height of the artificial limb;

the lack of remote monitoring of the biomechanical data collected by the prosthetic system.

The technical problem that the invention solves is to create a prosthetic system for the detection and compensation of the difference in the length of the human lower limbs which, based on the information obtained independently and automatically, the patient's prosthesis to adapt its length autonomously, without the intervention of a medical specialist or an attendant, until reaching a length equal to that of the contralateral biological limb, to monitor the patient's condition and to self-adapt continuously, during and according to the growth rate of the amputee.

The prosthetic system for detecting and compensating the difference in limb length, according to the invention, removes the above disadvantages in that, for the purpose of automatically, functionally and aesthetically equalizing the length of the prosthetic lower limb with that of the length of the contralateral lower limb, it consists of a system that uses a video camera device and a set of guidance landmarks managed by a dedicated software program for the detection of the difference in limb length, during the physiological or pathological growth of each individual patient, the resulting data providing the necessary input to the control of a self-adaptive prostheses managed by a microcontroller for the purpose of correcting the defect caused by the difference in the length of the limbs that appeared during the growth period of a patient, but also for permanent verification for the purpose of periodic control to maintain the alignment of the patient's lower limbs.

RO 138295 AO

By applying the invention, the following advantages are obtained:

- the patient's prosthesis changes its length autonomously, based on biomechanical determinations made in real time, eliminating possible errors caused by the performer or by the classic measurement methods used in prosthetics at this time;

- the prosthesis can manage the entire limb length difference detection system by itself;

- the adjustment of the self-adaptive prosthesis takes place autonomously, being also suitable for pediatric patients or patients with cognitive impairments, who normally would not be able to manage the adjustment of a prosthesis by themselves;

the system provides real-time feedback to the prosthesis user and/or an attendant via visual and/or acoustic and/or haptic signals regarding any changes that may or should occur;

- the system allows the prosthetic patient to always use a prosthetic limb of the correct size for several years, preventing the appearance of the difference in limb length which is the cause of related pathologies;

- eliminates the need to purchase several classic prostheses of different sizes during the period of growth of the pediatric patient;

- frequent visits to the prosthetics specialist are not necessary; favors the natural social reintegration of the prosthetic amputee.

Next, an example of the invention is given, with reference to fig. 1...3, which represent:

- fig. 1, block diagram with the functional connections of the prosthetic system for limb length difference detection and compensation;

- fig. 2, frontal view of the prosthetic manikin ready for use;

- fig. 3, view with the mechanism for simulating the difference in length of the mannequin's lower limbs.

The prosthetic system for the detection and compensation of the limb length difference, according to the invention, is composed of a self-adaptive prosthesis 1 containing an artificial leg 2 with passive or active ankle joint attached by means of a prosthetic cup 3 or by an implant with osseointegration at the abutment of a subject 4 unilaterally amputated at the transtibial level presenting a biologically contralateral 5 limb. A digital system 6, which can be a camera

RO 138295 professional AO, a smartphone or any other device containing a camera, operationally supported by a fixed support or a human companion 7, captures images that are processed by dedicated software in order to automatically and quickly detect the difference in the length of lower limbs of the prosthetic subject, with the help of small witnesses 8 positioned as a permanent or temporary tattoo, for example, on the tibial tuberosities of the subject's lower limbs and witnesses 9 positioned on a rigid surface behind the subject 4. The data determined regarding the difference in the length of the limbs with the system 6 are transmitted through a wireless interface 10 which is in functional connection with a wireless interface 11 connected to a microcontroller 12 which commands the elongation or compression of the self-adaptive prosthesis in order to equalize the length of the limbs of the subject 4 in correlation with the information detected automatically and without the intervention of a specialist, the prosthesis wearer or an attendant. The microcontroller 12 can provide feedback to the user via a module 13 in the form of various alerts regarding the status of the prosthesis and information regarding any action to be taken. Also, the data can be transmitted remotely, in real time, to a cloud-type network 14 where a medical and/or technical specialist 15 can have access through the connection with a digital system 16 through which he can occasionally monitor the status of the entire prosthetic system, it can perform preventive and corrective maintenance of the system or intervene in the process of automatic compensation of the difference in limb length.

A dummy 17, illustrated in fig. 2, contains the self-adaptive prosthesis 1 and a module 18 for simulating the growth of the lower limb by changing its length which is positioned between the fixed area a of the leg of the mannequin and the mobile area b corresponding to the leg of the mannequin. for the purpose of carrying out experimental tests, the dummy 17 can contain the witnesses 8 and 9 useful in determining the difference in limb length, but also for validating the entire process of detection and compensation of the difference in limb length with the help of an auxiliary standardized metrological system.

Module 18 for simulating the growth of the lower limb, illustrated in fig. 3, can contain an actuator 19 commanded by a microcontroller 20 that prints a translational movement to the element b in relation to the element a through a guide 21 that ensures the simulation of the increase/decrease in the length of the member considered biological, a movement monitored with a displacement transducer 22. A wireless interface 23 provides the bidirectional connection between the microcontroller 20 and the network 14 or an electronic device for control purposes.

RO 138295 AO

BIBLIOGRAPHY

1. S. Sabharwal, A. Kumar, Methods for assessing leg length discrepancy, Clinical Orthopaedics and Related Research, 466(12), 2910- 2922, 2007;

2. M. R. Petrone et al., The Accuracy of the Palpation Meter (PALM) for MeasuringPelvic Crest Height Difference and Leg Length Discrepancy, Journal of Orthopedic&Sports Physical Therapy, 33, 6, 319-325, 2003;

3. D. C. Fodor, N. E. Seghedin, Self-adaptive active prosthesis for the lower limb, RO137490A0, 2022;

4. Z. Vrhovski et al., System for Evaluation and Compensation of Leg Length Discrepancy for Human Body Balancing, Applied Sciences, 9(12), 2504, 2019;

5. Y. Salekzamani et al., Motorized leg length discrepancy measure: a new device for clinical use - a cross-sectional study, Crescent Journal of Medical and Biological Sciences, 9, 3, 161-167, 2022;

6. Z. O. Abu-Faraj et al., A holter-type, microprocessor-based, rehabilitation instrument for acquisition and storage of plantar pressure data, Journal of Rehabilitation Research and Development, 34, 2, 187-194, 1997.

Claims (3)

1. Prosthetic system which for the detection and compensation of the difference in length of human lower limbs is characterized by the fact that it consists of a self-adaptive prosthesis (1) controlled by a microcontroller (12) and attached to the abutment of a subject (4) unilaterally amputated at transtibial level showing a biologically contralateral limb (5) and a digital system (6), , the system (6) captures images that are processed by dedicated software in order to automatically and quickly detect the difference in length of the lower limbs of the prosthetic subject with with the help of small witnesses (8) positioned as a permanent or temporary tattoo on the tibial tuberosities of the subject's lower limbs and witnesses (9) positioned on a rigid surface behind the subject, the data determined with the system (6) regarding the difference of limb length are transmitted through the wireless interface (10) which is in functional communication with the wireless interface (11) connected to a microcontroller (12) which commands the elongation or compression of the self-adaptive prosthesis in order to equalize the length of the subject's limbs (4) in correlation with the information detected automatically and without the intervention of a specialist, the prosthesis wearer or an attendant, the microcontroller (12) being able to transmit to the user through a module (13) various alerts regarding the status of the prosthesis and information regarding any action to be taken happens, and the data can be transmitted remotely, in real time, to a cloud network (14) where a medical and/or technical specialist (15) can have access by connecting to a digital system (16). 2. Prosthetic system for detecting and compensating limb length difference, which for the purpose of testing, is characterized in that it consists of a dummy (17), containing the self-adaptive prosthesis (1) and the controls (8) and (9) useful in determining the difference in the length of the limbs, a module (18) for simulating the growth of the lower limb is used to change its length, being positioned between the fixed area (a) of the calf of the mannequin and the mobile area (b) corresponding to the foot of the mannequin, and for the validation the entire detection process may contain an auxiliary standardized metrological system. RO 138295 AO 3. Prosthetic system for detecting and compensating the difference in limb length, according to claim 2, characterized in that the module (18) for simulating the growth of the lower limb contains an actuator (19) controlled by a microcontroller (20) that prints the translational movement element (b) in relation to element a through the guide (21) which ensures the simulation of the increase and decrease in the length of the member considered biological, movement monitored with the displacement transducer (22), and a wireless interface (23) ensures the bidirectional connection between the microcontroller (20) and the network (14) or an electronic device for the purpose of digital control.