EP4213721A1

EP4213721A1 - Method and device for detecting and therapeutically monitoring knee ligament injuries

Info

Publication number: EP4213721A1
Application number: EP21785961.0A
Authority: EP
Inventors: Stéphane NOUVEAU; Henri Robert
Original assignee: Genourob
Current assignee: Genourob
Priority date: 2020-09-15
Filing date: 2021-09-15
Publication date: 2023-07-26
Also published as: FR3114020B1; US20230355168A1; CN116568210A; WO2022058686A1; FR3114020A1

Abstract

According to the method of the invention, a translational movement of the tibia of a patient is caused by a first motor (9b) for moving a thrust member (9a) of the patient's calf, and is measured by a first sensor (15a) located on the TTA. The tibia is caused to rotate by a second motor (12) for rotating a foot support (11b) of the patient, and is measured by a second sensor (14b) located as close as possible to the TTA. The respective operations of the first motor (9b) and the second motor (12) are correlated by a control member, by being mutually controlled according to pre-set and reproducible force models.

Description

DESCRIPTION

TITLE: Method and apparatus for the detection and therapeutic monitoring of knee ligament injuries.

Technical field of the invention

The invention relates to the field of measuring methods and apparatus intended for the detection, characterization and monitoring of injuries to the ligaments of a patient's knee. More specifically, the invention relates to a method and an apparatus for its implementation, making it possible to measure rotational instability of the knee in combination with a measurement of a translational movement of the tibia relative to the femur of a patient, at different degrees of knee flexion.

Terminology

In this patent, the following abbreviations, usual for those skilled in the art, will be used:

• ACL for “anterior cruciate ligament”

• TTA for “Anterior Tibial Tuberosity”

Prior art

Among the measuring devices used to establish a diagnosis, devices are known that make it possible to measure and monitor an anterior cruciate ligament lesion of a patient's knee. The anterior cruciate ligament (ACL) is made up of numerous collagen fibers that can be separated into two bundles according to their insertion on the tibia and the femur, including an anteromedial bundle and a posterolateral bundle. Depending on the trauma suffered by the patient, an ACL tear can be total or partial.

It is essential to be able to quickly detect and establish an accurate diagnosis of an ACL lesion, especially in the event of a partial lesion which is difficult to detect when the patient is hot after physical exertion. Such early diagnosis is particularly crucial for athletes whose knee strength conditions their performance. A start of ACL tear diagnosed as soon as possible allows the patient time to heal, avoiding the risk of permanent ACL tearing, and setting up suitable rehabilitation to protect the ligament during its healing.

It is important that the established diagnosis be as precise as possible in order to optimize the patient's rehabilitation methods within the framework of a therapeutic follow-up. The patient's condition must be monitored by repetitively, accurately and reliably measuring the progress of an improvement in the patient's ACL, which in particular makes it possible to best adapt his therapeutic follow-up.

For this purpose, devices are known for detecting a partial lesion of the ACL of the knee, such as for example the device described by the document EP2699160-B1 (GENOUROB). According to this document, the device comprises a seat for installing the patient, comprising a support plate for the patient's leg which is pivotally mounted on the seat. The patient's knee is immobilized on the plate and the patient's foot is immobilized on a foot support rotatably mounted on the plate.

The plate is equipped with a member for pushing the patient's calf, which is mounted so as to be able to move in translation on the plate. A first sensor measures a displacement in translation of the antero-superior face of the patient's tibia as a result of the thrust exerted on the calf by said thrust member. The foot support is equipped with a second sensor arranged as an inclinometer, to identify an angle of rotation of the tibia following a rotation of the foot support.

From the measurements made by the first sensor and the second sensor, a logic analysis system identifies a possible partial lesion of the anteromedial ligament and/or of the posterolateral ligament. To do this, the measurement is then established from a comparison between measurements carried out successively on the one hand for the leg potentially affected by an ACL lesion, and on the other hand for the healthy leg of the patient. A measurement of the internal and/or external rotation of the foot of a tested leg makes it possible to detect any rotational instability of the knee during a translational movement of the tibia relative to the femur caused via the thrust member, and this at different degrees of knee flexion. this allows to highlight a partial lesion of one of the two bundles of the ACL of the knee and rotational instability of the knee. Such a technique is therefore advantageous in that it makes it possible to detect with precision a lesion of the anteromedial bundle and/or a lesion of the posterolateral bundle which take into account the rotational instability of the knee.

Also known is the Japanese patent application JPH09276252A proposing a knee support and an ankle support, and a seat with a backrest mounted on the upper end of the base. It includes a forward pulling mechanism, a backward pressing mechanism and a measuring means are arranged on the knee support base. A subject's calf is pushed forward to impart forward pulling force to the knee joint ligament, and the upper surface of the patella placed on the hamstring support is pressed by the pressure imparting mechanism backwards to impart a rearward pressure force to the patella.

The forward movement of the vertically displaced tibia is measured as a function of the displacement of the upper surface of the patella by the measuring means.

Patent WO2008/040790 is also known, describing a device for detecting and monitoring a lesion (rupture or tear) of the ACL by anterior translation of the tibia relative to the femur comprising a lower limb support characterized in that it comprises a pushing means for the postero-upper face of the calf and a tibia displacement sensor positioned on the antero-upper face of the tibia, on the ATT (Anterior Tibia Tuberosity).

Patent EP2839775 proposes a device for determining a relative position of a femur with respect to a tibia comprising at least:

- a first measuring member intended to be positioned against the tibia and comprising means for generating a signal representative of a position of the measuring member; a second and a third measurement member intended to be positioned relative to the femur, each encircling the thigh associated with the femur at different heights, the second and the third measuring device each comprising means for generating a signal representative of a position of the associated measuring device;

- a calculating unit comprising communication means for receiving at least the signals generated by the first, second and third measuring units, comparison means which compare the signals from the second and third units to deduce therefrom an absolute position of the femur and processing means which analyze the signal from the first measurement member and the absolute position of the femur to deduce therefrom a relative position of the femur with respect to the tibia.

Patent EP3178381 relates to an evaluation device, for evaluating morphological parameters of a lower limb of a patient, in particular during a preoperative or postoperative consultation, the evaluation device being characterized in that it comprises at less :

- a femoral set of inertial sensors comprising three femoral gyrometers and three femoral accelerometers, the femoral gyrometers being configured to respectively generate signals representative of their respective angular velocities around the three dimensions of a Galilean frame of reference, the femoral accelerometers being configured to generate signals representative of their respective linear accelerations according to the three dimensions of the Galilean frame of reference,

- a tibial set of inertial sensors comprising three tibial gyrometers and three tibial accelerometers, the tibial gyrometers being configured to respectively generate signals representative of their respective angular velocities around the three dimensions of a Galilean frame of reference, the tibial accelerometers being configured to generate signals representative of their respective linear accelerations according to the three dimensions of the Galilean frame of reference, - a femoral support configured to hold the femoral inertial sensor assembly on the patient's thigh, the femoral support having: i) a proximal femoral attachment portion configured to secure the femoral support on a proximal portion of the thigh, and ii) a distal femoral fixation portion configured to fix the femoral support to a distal portion of the thigh,

- a tibial bracket configured to hold the tibial inertial sensor assembly to the patient's leg, the tibial bracket having: i) a proximal tibial attachment portion configured to secure the tibial bracket to a proximal portion of the leg and ii) a distal tibial fixation portion configured to fix the tibial support to a distal portion of the leg,

- a malleolar feeler fixed to the tibial support, the malleolar feeler comprising a medial branch and a lateral branch which are articulated to the tibial support so as to be movable between: oi) a contact configuration, in which a contact zone of the medial branch and a side branch contact zone are brought into contact with the medial malleolus and the lateral malleolus, respectively, and o ii) a distant configuration, in which the medial branch and the lateral branch are distant from the medial malleolus and the lateral malleolus, and o a calculation unit configured to receive the signals generated by the femoral gyrometers, by the femoral accelerometers, by the tibial gyrometers and by the tibial accelerometers, the calculation unit being further configured for:

■ receiving said signals generated when the tibial assembly of inertial sensors follows a first circular movement induced when the lower limb in extension or in hyperextension rotates around the femoral head of the patient, ■ calculate, from the signals received, the position of the center of the femoral head,

■ receiving said signals generated when the femoral set of inertial sensors is stationary, the patient's thigh being stationary and in extension or hyperextension, and when the tibial set of inertial sensors follows a second circular movement induced by at least one flexion of the upper leg at 60 degrees, for example higher than 90 degrees,

■ calculate, from the signals received, the position of the center of the knee,

■ receiving said signals generated when the medial branch and the lateral branch are brought into contact respectively with the medial malleolus and with the lateral malleolus while the foot is immobile, and calculating, from said signals received, the position of the center of the ankle as the midpoint of the segment bounded by the medial branch contact area and the side branch contact area when the medial branch and the side branch are in contact configuration.

Presentation of the invention

The subject of the invention is a method for evaluating a cruciate ligament lesion of the knee of a patient, by implementing an apparatus of the aforementioned type according to which measurements are carried out to identify a possible rotational instability of the knee in combination with a translational movement of the tibia relative to the femur, at different degrees of knee flexion.

The apparatus is of the aforementioned type comprising a seat placed on a base (6) comprising an extended seat with a backrest that can be tilted with respect to the seat, and an installation plate for the leg of a patient which is movably mounted in tilting relative to the seat. A thrust member for the patient's calf is mounted to move in translation on the plate and a first sensor is assigned to the measurement of a displacement in translation of the patient's tibia as a result of the thrust exerted against the calf. A foot support is rotatably mounted at the end of the plate, to cause rotation of the tibia and a second sensor is assigned to the measurement of an angle of rotation of the tibia. A logic system for analyzing the measurements taken by the first sensor and by the second sensor makes it possible to diagnose and/or monitor the evolution of a possible partial lesion of the ACL of the knee.

It appeared in use that such a device and its methods of implementation could be improved to improve its ergonomics, the quality of the diagnosis obtained and the adaptation of a therapeutic follow-up of the patient, including if necessary in postoperative phase.

On the basis of this observation, the object of the invention is in particular to propose such improvements to apparatuses belonging to the prior art.

A related objective is to allow demonstration of a lesion of the lateral capsulo-ligamentary structures at the level of the knee joint - such as in particular the antero-lateral ligament or other lateral capsulo-ligamentary structures - which have a strong influence on the rotational instability of the knee, making it very difficult to assess it objectively.

Another related objective is to make it possible to rapidly detect a lesion of the ACL of a patient's knee, by being able, if possible - in particular during therapeutic follow-up - to abstain, without prejudice to the relevance of the diagnosis obtained, from then comparing measurements carried out respectively for the leg affected by a lesion of the ACL of the knee and for the healthy leg of the patient.

Another related objective is to find ways to measure rotational instability of the knee in combination with translational and rotational movement of the tibia relative to the femur, making it possible to increase the relevance of the diagnosis which is deduced therefrom and/or to avoid a loss of reliability of the measurements carried out in the event of translation or tibial rotation tests alone.

Another related objective of the invention is to improve the ergonomics of the device, by allowing the practitioner to perform reliably and quickly various measurements in translation and rotation of the tibia during therapeutic follow-up of the patient, at from which he can establish a precise diagnosis of the evolution of the lesion of the ACL of the patient's knee by easily adapting his examination methods.

Another related objective is to obtain reliable and precise measurements favoring the relevance of their comparison with similar measurements subsequently carried out within the framework of a therapeutic follow-up, in particular in the postoperative phase of the patient. More precisely, the goal is to take into consideration an evaluation of the evolution of the resistance of a transplant during repeated tests throughout the rehabilitation and the resumption of a pivotal sport of the patient, to detect a potential relaxation of the transplant.

More specifically, the aim is to make it possible to evaluate an apparent distension of the transplant from the measurements taken via the device during the first months, to correct exercises performed by the patient in the postoperative phase in order to make them less restrictive. It is thus finally sought to allow the transplant to tighten thanks to the process of reconstruction of the graft of the transplant, which is not an ordinary healing, by promoting early and progressive post-operative care of the patient.

It is also more specifically aimed at providing a precise analysis of the translation associated with the internal rotation of the tibia, in particular to achieve an objective and precise study of potentially existing lesions of the lateral, antero-lateral and/or postero-lateral capsulo-ligamentary structures. lateral, based on a comparative analysis of the measurements precisely taken in the patient's post-operative phase.

To do this and according to an approach of the invention, both in its generality and in its specificities, the invention proposes via a control device to enslave in correlation motorized rotation of the patient's foot and motorized translational displacement of the tibia relative to the femur at different degrees of knee flexion caused by the thrust member.

The rotation of the foot support controlled by the control member in correlation with the thrust exerted against the patient's calf, at different degrees of knee flexion, has the advantage of causing an equivalent to jump tests which is problem to be carried out manually by a practitioner in an awake subject. This also makes it possible to objectify the examination carried out of the patient under conditions of optimum reproducibility during the therapeutic follow-up of the patient.

In addition, such servo-control makes it possible to easily carry out such jump tests at different stressing thresholds of the tibia, according to various predefined examination methods and/or adaptable by the practitioner according to the evolution of the ACL lesion during therapeutic follow-up of the patient.

It is thus not only possible to overcome the difficulty for a practitioner to carry out the test manually, but also to obtain on the one hand reliable and precise measurements and on the other hand a possibility of identical reproduction - in the framework of a therapeutic follow-up - the combined movements of rotation of the foot and translation of the tibia with respect to the femur operated under control of the control device.

The practitioner is also allowed to adapt the correlated servoing of the rotational and translational movements imparted to the tibia, by being able to modify the stressing efforts of the tibia according to the evolution of the healing of the ACL lesion and/or based on the practitioner's search for an identification of a specific ligament injury in the patient's knee.

The rotation of the foot support by the control member is preferably carried out at constant speed, according to a torque supplied by the foot rotation drive motor which is selected from force laws listed in a range of several torques to be applied between 3 N/m and 8 N/m (N/m: Newton per meter of lever arm), depending on the rotation amplitude of the foot and/or motorized translational movement of the tibia via the thrust member.

The rotation of the foot support can be carried out according to an internal angle then according to an external angle of values varying for example over a range of angles which can extend up to 45 degrees on either side of a position neutral of the foot in position at the zenith of the anterior tibial tuberosity, depending on the torque applied. The motorized displacement in translation of the tibia is achieved by applying - according to an amplitude of displacement of the thrust member - of a force which can for example reach 134 N (N: Newton) - or according to the international reference 30 lbs (lbs: pounds) -, in accordance with listed effort laws.

Such a servo-control makes it possible to measure either simultaneously or consecutively on the one hand an angle of rotation of the tibia and on the other hand a displacement in translation of the tibia, while allowing a logical correlation by an analysis system of the measurements respectively obtained .

In particular within the framework of a therapeutic follow-up, it is thus avoided a loss of reliability of the setting in combination of the measurements carried out relating to the setting in mobility of the tibia in translation compared to the femur and to its setting in rotation, compared to such measurements obtained by setting the mobility of the tibia not controlled and/or necessarily carried out only simultaneously in rotation and in translation.

In addition, the practitioner has the possibility of carrying out diversified measurements at different degrees of given flexion of the knee, according to various selected conditions of rotation of the tibia combined with its displacement in translation, and this simultaneously and/or consecutively. The diversification of the measurements obtained allows the practitioner to compare the results of the logical analysis obtained to increase the relevance of his diagnosis.

It emerges that the precision, diversity and adaptation that can be configured by the practitioner of the methods of capturing the measurements, makes it possible to quickly and easily establish a reliable and relevant diagnosis from said correlated servoing of the motorizations respectively assigned to the rotation of the tibia and to its displacement in translation, and this independently of the simultaneous and/or successive implementations of said motorizations.

This is particularly useful in the context of early detection of a possible injury to the ACL of the knee. This is also particularly useful in the context of therapeutic follow-up of the patient, from a modeling of the modalities of mobility of the tibia via said motorizations servo-controlled in correlation on the basis of pre-established effort models, allowing their subsequent reproduction. identically and/or adapted in the context of the therapeutic follow-up of a specific patient.

It is also proposed to place the second sensor for measuring a rotation of the tibia as close as possible to the anterior tibial tuberosity—hereinafter referred to as TTA. Such a position of the second sensor provides reliable and precise measurements of the angle of rotation of the tibia closest to the femoro-tibial joint, which improves the relevance of the diagnosis obtained, in particular because of its distance from the foot to which it is applied rotation of the tibia.

This makes it possible to avoid interference with the measurements taken by the second sensor and/or to obtain precise measurements of the effective rotation of the tibia by comparison with a given angle of rotation of the foot support. It is also avoided potential interference on the measurements provided by the second sensor which could affect their relevance. Such interferences are likely to occur in the event of an overestimation of the amplitude of the angle of rotation of the tibia as a result of the movements induced by the joints of the foot and the ankle, and/or due to the mass of collagenous tissues interfaced between the patient's foot and knee.

An assistance device is preferably used to guide the practitioner in positioning the first sensor and/or the second sensor on the patient. A signal transmitter, such as sound and/or visual signals, can be used for this purpose based on a prior calibration of the sensors in a reference position. Such a calibration is also advantageously used for the construction models of efforts exploited by the control unit to reproduce and/or adapt - during the therapeutic follow-up of the patient - the methods of putting the tibia under stress and consequently the measurements previously carried out and stored for a specific patient.

The second sensor can be placed on the leg segment as close as possible to the antero-superior part of the tibia, preferably on the tibial edge (close to the ATT). The second sensor is potentially placed as a temporary replacement for the first sensor preferably placed in the active position against the ATT. This is particularly useful for best placing the second sensor in application close to the ATT without excluding a measurement previously or subsequently carried out by the first sensor then placed on the ATT, in the case of respective measurements of the rotation of the tibia and its displacement in translation which are carried out alternately under the control of the control member.

Account is therefore taken of the potential presence of the first sensor for measuring the displacement in translation of the tibia, which is preferably placed in application against the ATT.

In the case of simultaneous measurements of the angle of rotation of the tibia and its displacement in translation, the second sensor is then placed as close as possible to the ATT in the immediate vicinity of the first sensor following the extension of the patient's leg, in being for example mounted on a legging at least partially enclosing the patient's calf. In the case of consecutive measurements of the angle of rotation of the tibia and its displacement in translation, the second sensor can then be placed on the ATT as a temporary replacement for the first sensor which are then advantageously jointly mounted independently movable on an articulated bracket.

Moreover, the seat is furthermore equipped with various motor members via which the patient is installed on the seat in the examination position. Such motor organs are assigned at least to the relative positioning of the components of the seat, in particular to the positioning in relative inclination between and the seat and the backrest, at the positioning in relative inclination between the plate and the seat, and alternatively to the positioning in elevation of the seat.

It is therefore also proposed to model for a given patient the conditions of initial examination of a patient, and therefore the conditions under which the measures of mobility of the tibia are carried out. Such a model of the patient's examination conditions is produced from a memorization of the relative positions between the movable components of the seat, from which memorization the various motor organs assigned to the components of the seat are implemented. Thus, the conditions of an initial examination at different degrees of flexion of the patient's knee can be reproduced with precision during his therapeutic follow-up, in particular via the control member.

In the light of what has just been explained, a method relating to the invention is a method for evaluating a lesion of the ACL of the knee of a patient, at least by measuring rotational instability of the knee in combination with a measurement of a translational displacement movement of the tibia relative to the patient's femur at different degrees of knee flexion.

The method implements an apparatus at least comprising a seat for installing the patient comprising an extended seat with a reclining backrest relative to the seat, and comprising a support plate for a patient's leg which is mounted tilting in position on the seat. The plate is equipped with a first member for immobilizing the patient's knee on the plate, with a foot support which is provided with a second member for immobilizing the patient's foot and which is rotatably mounted on the plate, and a thrust member for the patient's knee mounted movable in translation on the plate, the device being equipped with a first sensor for measuring a translational displacement of the tibia relative to the femur placed on the ATT, and a second sensor for measuring an angle of rotation of said tibia close to the ATT.

According to such a method, said evaluation of an ACL lesion is diagnosed from a collection and a logical processing by a measurement analysis system at least comprising a first measurement provided by the first sensor and a second measurement provided by the second sensor for each of said different degrees of knee flexion.

In this context, a method in accordance with the invention has the following characteristics:

-) the measurement of the displacement in translation of the tibia is carried out by the first measurement sensor from a translation of the thrust member on the plate which is operated by a first motor,

-) the measurement of the angle of rotation of the tibia is carried out by the second sensor placed closest to the ATT of the patient's knee, from a rotation of the foot support which is operated by a second motor,

-) The respective implementations of the first motor and the second motor are controlled in correlation by a first control module that includes a control device,

-) The respective activation methods of the first motor and of the second motor are regulated dependent on each other, in particular with regard to their kinematics, their dynamics and their simultaneous and/or consecutive implementations, according to at least one model of efforts listed for stressing the tibia of a specific patient which is pre-established and reproducible and/or adaptable according to the evolution of the lesion of the ACL of the patient's knee, in particular within the framework of a therapeutic follow-up of the patient for which said at least one effort model is listed,

-) said at least one force model combines, for each of the degrees of flexion of the patient's knee, on the one hand a first force law relating to the translational displacement of the tibia, via the displaced thrust member in translation on the plate by the first motor, and on the other hand a second force law relating to the rotation of the patient's foot, via the foot support, by the second motor for rotating the foot support .

According to one implementation of the method, the second sensor is placed close to the thrust member following the extension of the leg, the first sensor being placed on the ATT and the second sensor being placed adjacent to the first sensor. In this case, the second sensor is for example mounted on a leg piece installed at least partially around the patient's calf.

According to a variant, the second sensor and the first sensor are mounted on an articulated bracket which is fixed to the plate, on which bracket the second sensor and the first sensor are installed selectively in isolation and/or jointly individually mobile on the bracket.

In other words, only the first sensor can be installed on the stem and the second sensor can be placed adjacent to the first sensor, for example being mounted on said leg piece. According to a variant, the first sensor and the second sensor can be jointly installed on the same said bracket, or be installed on said respective brackets. In this case, the bracket or brackets are equipped with respective members for mounting the first sensor and the second sensor on the bracket or brackets, in respective adjustable positions.

This makes it possible to selectively carry out measurements of the mobility of the tibia on the one hand by respective applications on the ATT for the first sensor and close to the ATT for the second sensor to carry out said measurements simultaneously, and/or by applications individual alternately of the first sensor or of the second sensor against the ATT, to carry out said measurements consecutively to improve their accuracy as needed.

Thus, the second sensor can be placed on the ATT as a temporary replacement for the first sensor. The first sensor is for example mounted in isolation on the stem and the second sensor is mounted on the leg guard, and/or the first sensor and the second sensor are jointly mounted on a stem or are mounted on respective stems, being selectively applied in alternation against the TTA.

Thus, according to first examination methods, the measurement of the translational displacement of the tibia by the first sensor and the measurement of the angle of rotation of the tibia by the second sensor, are carried out simultaneously under control of the control member in accordance with the says at least one effort model. Thus again according to second examination methods, the measurement of the translational displacement of the tibia by the first sensor and the measurement of the angle of rotation of the tibia by the second sensor, are carried out consecutively under control of the control member in accordance at least said effort model.

According to an implementation of the method and prior to an evaluation examination of a lesion of the ACL of the knee of a specific patient, the first sensor and the second sensor are calibrated in respective reference positions, by examination of a healthy leg of the patient subjected to said at least one stress model.

Such a calibration being carried out and taking into account the correlated implementations of the first motor and of the second motor according to said at least one pre-established effort model, the examination of the patient's knee during a therapeutic follow-up can be carried out directly without new measurements taken on the healthy leg.

According to one implementation of the method, the control member comprises a second servo control module correlated with at least a third motor for positioning in relative inclination between the seat and the backrest, a fourth motor for positioning in relative inclination between the plate and the seat, and a fifth positioning motor in elevation of the seat. The respective strokes of the third motor, of the fourth motor and of the fifth motor are in particular regulated dependent on one another according to at least one pre-established and reproducible seat configuration model for a specific patient. Said seat configuration model is constructed in particular during an initial examination of the patient to detect a possible lesion of the ACL.

The invention also relates to an apparatus configured for the implementation of a method in accordance with the invention. The device of the invention is of the type of device comprising said seat comprising an extended seat with a backrest that can be tilted relative to the seat, and comprising a support plate for the patient's leg which is mounted tilting in position on the seat and which is equipped with a first member for immobilizing the patient's knee on the plate, such as for example arranged as a knee tightening strap on a knee support base. The plate is also equipped with a knee thrust member mounted movable in translation on the plate and with a foot support which is provided with a second member for immobilizing the patient's foot on the foot support, such as for example arranged as a strap for tightening the foot and the base of the leg on the foot support. The foot support is rotatably mounted on the plate.

The apparatus also comprises a member for positioning the first sensor on the ATT and a second member for positioning the second sensor relative to the foot support.

The apparatus also comprises a system for analyzing the measurements respectively supplied by the first sensor and by the second sensor and relating to their travels following a setting in motion of the tibia respectively in translation and in rotation, and an interface for display of data provided by the analysis system from which a diagnosis of at least partial lesion of the ACL of the knee is deduced by a practitioner.

According to the invention, the apparatus comprises said first motor assigned to a translational setting of the thrust member and said second motor assigned to a rotational setting of the foot support. The apparatus also comprises said first control module which comprises said control member for correlated implementations of the first motor and of the second motor, in accordance with the application of said at least one pre-established force model and stored in a first directory via a first memory equipping said first control module.

Said at least one effort model is assigned to a specific patient and/or is selected by the practitioner, via for example a menu with selective choices, according to the examination to be performed from among a plurality of standard effort models previously established and listed in the first memory. The first repertoire of effort models can be upgraded during the therapeutic follow-up of the patient, by being adapted and/or supplemented by the practitioner with one or more new effort models specific to the patient. According to one embodiment, at least one said second member for positioning the second sensor is configured to be placed on the patient in an area of one of the patient's legs located closest to the ATT of the patient's knee.

A said second member for positioning a said second sensor is for example arranged in a said leg piece for at least partially enclosing the patient's calf placed close to the thrust member, and/or is part of a said gallows articulated which is fixed to the plate and which is moreover potentially carrying the first sensor.

According to an advantageous embodiment, the first member for positioning the first sensor and a said second member for positioning a said second sensor are mounted on at least one articulated bracket which is fixed to the plate.

The potentially alternate or joint uses of a second sensor mounted on the leg piece and/or of a second sensor mounted on the stem, allows the practitioner to perform diversified measurements of the rotation of the tibia. The practitioner can selectively use, in isolation or in combination, a second sensor mounted on the leg piece by being placed close to the ATT and/or a second sensor mounted on the stem and applied against the ATT as a temporary replacement for the first sensor. Such a combination of use of several second sensors makes it possible to refine the detection of rotational instability of the knee.

According to one embodiment, the apparatus is provided with at least one assistance device comprising a signal transmitter capable of indicating to a practitioner correct positioning of the first sensor and/or of the second sensor on a specific patient, with regard to reference positions respectively of the first sensor and/or of the second sensor on the patient which are previously defined and stored in a second directory of positions of the individualized sensors for various patients via a second memory of the assistance device.

Following the application of the first sensor and/or the second sensor to a specific patient's leg during an initial examination, a calibration of the sensors is performed at reference positions of the sensors which are then stored in the second directory.

During a subsequent examination, in particular in the context of therapeutic follow-up of the patient, the practitioner can reproduce the positioning of the first sensor and/or of the second sensor on the same patient in accordance with their respective previously stored reference positions, by being guided by an audible signal and/or by a light signal emitted by the assistance device. A reliable reproducibility of the initial examination is obtained, which reinforces the relevance of the diagnoses then made during the therapeutic follow-up of the patient.

According to one embodiment, the control member comprises a second control module for at least one configuration of the seat for a specific patient, the second control module being a servo module correlated with at least a third motor for positioning in relative inclination between the seat and the backrest, a fourth motor for positioning in relative inclination between the plate and the seat, and preferably a fifth motor for positioning in elevation of the seat.

The second control module comprises a third memory for storing a third directory of individualized seat configuration models for various patients which are previously established and which are reproducible by the control unit.

Presentation of figures

The invention will be better understood on reading the following detailed description of an embodiment of the present invention, in relation to the following figure:

[Fig. 1] Figure (1) is a schematic presentation of the profile of a patient installed on a seat that includes a device according to an embodiment of the invention.

Detailed description of the invention The figure and its non-limiting detailed description, expose the invention according to particular modalities which are not restrictive as to the scope of the invention. The figures and their detailed descriptions of an exemplary embodiment of the invention can be used to better define it, if necessary in relation to the general description which has just been given.

In FIG. 1, an apparatus is organized to assess a possible injury to the ACL of a patient's knee. The apparatus comprises a seat (1) for installing the patient for his examination by a practitioner. The seat (1) comprises a seat (18) and a backrest (19) which can be tilted relative to each other, the position of the seat (18) being adjustable in height. A plate (17a) for supporting the patient's leg is mounted on a support (17b) which is pivotally articulated with respect to the seat (18)).

The seat (1) can thus be placed in various specific configurations for installing the patient on the device, by adjusting the relative positions between the seat (18), the backrest (19) and the plate (17a). During an examination of the patient, the practitioner can thus modify the configuration of the seat (1) according to specific methods of implementation of the device in order to establish an evaluation at various degrees of flexion of the patient's knee.

The plate (17a) is equipped with a base (11a) for supporting the patient's knee. The tray (17a) is also equipped with a foot support (11b) receiving the patient's foot and with a thrust member (9a) comprising a shell (9c) on which the patient's calf rests, close to his knee.

The patient's knee is firmly held on the base (11a) via a first immobilization member (16) arranged in a strap for enclosing the knee on the base (11a). The patient's foot is firmly held on the foot support (11 b) via a second immobilization member (13) arranged in a strap gripping at least the foot and the base of the patient's leg on the support foot (11b).

The thrust member (9a) is mounted to move in translation on the plate (17a), to exert a thrust force against the patient's calf at a desired force threshold. The foot support (11b) is rotatably mounted on the plate (17a), to cause rotation of the tibia at a desired force threshold.

The apparatus is equipped with different motors (4, 5, 7) to adjust the configuration of the seat (1) at various patient examination stations. The motor (4) adjusts the inclination between the seat (18) and the backrest (19). The motor (7) makes it possible to adjust the inclination between the seat (18) and the plate (17a) via the support 10 carrying the plate (17a). The motor (5) makes it possible to adjust the elevation position of the seat (18).

The apparatus is also equipped with various motors (9b, 12) to place the patient's tibia under stress in translation and/or in rotation. A first motor (9b), such as in particular an electric actuator, is assigned to the translation maneuver of the thrust member (9a), in order to cause a translational movement of the tibia relative to the femur. A second motor (12), such as in particular an electric rotary motor, is assigned to the rotational maneuver of the foot support (11b), in order to cause rotation of the patient's tibia.

The device is also equipped with a first sensor (15a) for measuring the translational displacement of the tibia following the activation of the first motor (9b) causing the translational displacement of the thrust member (9a).

The first sensor (15a), such as a proximity sensor with potential difference, is mounted on a bracket (15b) fixed to the plate (17a) by being applied against the ATT during the examination of the patient. A second sensor (14b) such as a potential difference proximity sensor configured as an inclinometer and/or an accelerometer, is mounted according to the example illustrated on a leg piece (14a) for enclosing the patient's calf by being applied against the tibia close to the first sensor (15), as close as possible to the ATT.

A Man/Machine Interface hereinafter referred to as HMI - allows the practitioner to establish his diagnosis from the logic processing by a system for analyzing the measurements provided at least by the first sensor (15a) and the second sensor (14b) which are performed at different degrees of knee flexion by tilting the plate (17a) relative to the seat (18) according to the predefined configurations of the seat (19).

At the end of a patient examination sequence, a display interface of the logical processing of the measurements carried out by the analysis system provides a display of the result obtained in the form of a diagram. The diagram includes two comparative curves, including a reference curve relating to an absence of ACL injury (green curve) and a curve relating to a possible ACL injury (red curve) identified by the analysis system from the treatment of measurements taken.

To perform the examination of the patient, a control member that comprises the HMI comprises a second control module which regulates the implementation of the motor (4), the motor (5) and the motor (7) to place the seat (19) according to previously defined configurations at different degrees of knee flexion.

The configurations of the seat (19) are then applied according to configuration models of the seat (19) which are selected and/or adaptable by the practitioner, and which are classified according to a third directory previously established and stored in a third memory of the second module control.

Prior to an examination of the patient, the first sensor (15a) and the second sensor (14b) are calibrated by being placed in reference positions (15b, 14a), respectively against the TTA for the first sensor (15a) and near of the ATT for the second sensor (14b) according to the example illustrated. The HMI comprises an assistance device guiding the practitioner to reproduce the reference positions (15b), (14a) of the first sensor (15a) and of the second sensor (14b) to carry out an examination of the patient. The respective reference positions (15b, 14a) of the sensors (15a, 14b) are classified according to a second directory previously established and stored in a second memory of the assistance device. Subsequently during a therapeutic follow-up of the patient, the positions of installation of the sensors (15b, 14a) by the practitioner are compared with their respective reference positions (15a, 14b), to define the relevance of the subsequent positioning of the sensors (15a, 14b) on the patient. In the event of a position shift of the sensors (15a and 14b) with respect to their previously stored reference positions (15b, 14a), the practitioner is then guided via a transmitter of a signal - sound and/or light - to placing the first sensor (15a) and the second sensor (14b) on the patient in accordance with their respective reference positions (15a, 14b).

To perform an examination of the patient, the practitioner uses the MMI to cause the translational movement of the thrust member (9a) and the rotation of the foot support (11b). To this end, the control unit comprises a first control module for implementing the first motor (9b) and the second motor (12), which are regulated in correlation by the first control module.

More particularly for a patient examination phase, the forces and/or the amplitudes of stressing the tibia in translation - via the first motor (9b) - and in rotation - via the second motor (12) are regulated according to effort models selected and/or adaptable by the practitioner, which are classified according to a first directory established beforehand and stored in a first memory. Each of the force models comprises a first force law regulating the operation of the first motor (9b) and a second force law regulating the operation of the second motor (12).

The first motor (9b) and the second motor (12) are thus slaved in combination, by applying a force model - combining in correlation a said first law of force and a said second law of force - which is selected by the practitioner from among various effort models listed in the first memory, and this for various degrees of inflection of the knee.

The implementation of the first motor 9a and the second motor 12 according to a model of effort selected by the practitioner makes it possible to regulate - via the control member - the methods of placing the tibia under stress desired by the practitioner. From the application of an effort model, a combined servoing of the first motor (9a) and the second motor (12) by the first control module makes it possible to subject the patient's tibia to a constraint in translation and in rotation according to forces and amplitudes which are correlated, being able to be selectively applied - on requests from the practitioner - simultaneously or consecutively.

The various measurements of the mobility of the tibia in translation and/or in rotation are selectively carried out by the practitioner according to predefined effort models adapted to a specific patient, from which effort models the respective implementations of the first motor (9b) and the second motor (12) are correlated. The effort models are pre-established on the basis of standardized effort models or on the basis of specific effort models constructed and/or potentially adapted during an initial examination of a patient, being reproducible during a therapeutic follow-up of the patient and/or adapted according to the evolution of the ACL lesion identified during the initial examination.

A precise and reliable diagnosis can thus be quickly established by the practitioner, taking into account a rotational instability of the tibia evaluated precisely from various measurements of a translation of the tibia and a rotation of the tibia which are correlated on both sides. combined enslavement of the implementations of the first motor (9b) according to a so-called first specific force law and of the second motor (12) according to a said second specific force law.

The reproducibility of the examination during a therapeutic follow-up is thereby made more reliable and/or can be adapted according to the evolution of the patient's ACL lesion, based on a choice by the practitioner of the effort models to be applied and /or to adapt. The accuracy of the measurements performed is also enhanced by applying the first sensor (15a) and/or the second sensor (14b) against the TTA, or at least as close as possible to the TTA.

The analysis system can provide effective and comparative results between measurements whose measurement methods can be diversified while being easy to implement by the practitioner on the basis of pre-established and/or adapted effort models. The interlocking of the constraints applied to the tibia for its displacement in translation for various configurations of the seat - under the control of the implementation of the first motor (9b) and of the second motor (12) by the control member - contribute to the quality and the precision obtained - via the analysis system - from the analysis of the measurements carried out.

Use of patented equipment

The aforementioned apparatus is intended in particular for preoperative diagnosis.

It makes it possible to implement a method for measuring a rotational movement of a knee of a patient in combination with a measurement of a movement of displacement in translation of the associated tibia with respect to the associated femur of the patient at different degrees knee flexion, the method being implemented by a device at least comprising a seat (1) for installing the patient comprising a seat (18) extended by a backrest (19) tiltable with respect to the seat (18 ), and comprising a plate (17a) for supporting a leg of the patient which is mounted tilting in position on the seat (18), the plate (17a) being equipped with a first member (16) for immobilizing the patient's knee on the plate (17a), a foot support (11 b) which is provided with a second member (13) for immobilizing the patient's foot and which is rotatably mounted on the plate (10 ), and a thrust member (9a) for the patient's knee which is mounted to move in translation on the plate (17a), the apparatus being equipped with a first sensor (15a) for measuring a translational displacement of the tibia relative to the femur placed on the ATT, and a second sensor (14b) for measuring an angle of rotation of said tibia, close to the TTA, according to which method a collection and a logical processing are carried out by a measurement analysis system at least comprising a first measurement provided by the first sensor (15a) and a second measurement provided by the second sensor (14b) for each said different degrees of knee flexion, characterized in that:

-) the measurement of the displacement in translation of the tibia is carried out by the first measurement sensor (15a) based on a translation of the thrust member (9a) on the plate (17a) which is operated by a first motor (9b),

-) the measurement of the angle of rotation of the tibia is carried out by the second sensor (14b) placed closest to the ATT of the patient's knee, from a rotation of the foot support (11b) which is operated by a second motor (12), and

-) The respective implementations of the first motor (9b) and of the second motor (12) are controlled in correlation by a first control module that comprises a control member,

-) the respective activation modes of the first motor (9b) and of the second motor (12) are regulated dependent on each other according to at least one model of efforts listed for stressing the tibia of a patient specific which is pre-established and reproducible and/or adaptable to the patient in question,

-) said at least one force model combines, for each of the degrees of flexion of the patient's knee, on the one hand a first force law relating to the translational displacement of the tibia, via the thrust member ( 9a) moved in translation on the plate (17a) by the first motor (9b), and on the other hand a second force law relating to the rotation of the patient's foot, via the foot support (11b) , by the second motor (12) for rotating the foot support (11 b).

Preferably, the second sensor (14b) is placed close to the thrust member (9a) following the extension of the leg, the first sensor (15a) being placed on the TTA and the second sensor (14b) being placed adjacent to the first sensor (15a), close to the TTA.

Advantageously, the second sensor (14b) is mounted on a leg piece (14a) fitted around the patient's calf.

According to first examination methods, the measurement of the translational displacement of the tibia by the first sensor (15a) and the measurement of the angle of rotation of the tibia by the second sensor (14b) are carried out simultaneously under the control of the controller in accordance with said at least one effort model. According to second examination methods, the measurement of the translational displacement of the tibia by the first sensor (15a) and the measurement of the angle of rotation of the tibia by the second sensor (14b) are carried out consecutively under the control of the controller in accordance with said at least one effort model.

Advantageously, prior to a reading of measurements on the patient, the first sensor (15a) and the second sensor (14b) are calibrated in respective reference positions (15b, 14a) by examination of a healthy leg of the patient subjected to said at least one effort model.

Preferably, the control member comprises a second servo control module correlated with at least a third motor (4) for positioning in relative inclination between the seat (18) and the backrest (19), a fourth motor (7) for positioning in relative inclination between the plate (17b) and the seat (18), and of a fifth motor (5) for positioning the seat (18) in elevation, the respective strokes of the third motor (4), the fourth motor (7) and the fifth motor (5) being regulated dependent on each other according to at least one configuration model of the seat (3 and 8) pre-established and reproducible for a specific patient.

Claims

28

Claims

1 - Measuring device for the characterization of a lesion of the anterior cruciate ligament of the knee (ACL) of a patient, comprising a seat (1) provided with a seat (18) having a reclining backrest (19), a (17a) for supporting the patient's leg, movable in rotation relative to the seat (18) and a member (9a for pushing the patient's calf (2) equipped with a first immobilizing member (16 ) of the patient's knee on the plate (17a), a thrust member (9a) of the knee mounted movable in translation on the plate (17a)

Characterized in that said apparatus further comprises:

- a foot support (11 b), rotatable on the plate (17a), capable of causing rotation of the tibia at a desired force threshold, said foot support (11 b) being provided with a second member (13) for immobilizing the patient's foot a first sensor (15a) capable of being positioned on the ATT of said patient as well as a second sensor (14b) assigned to the measurement of an angle of rotation of the tibia and mounted on a member for positioning said second sensor relative to the foot support (11b)

- a system for analyzing the measurements respectively supplied by the first sensor (15a) and by the second sensor (14b) and relating to their strokes following a setting in motion of the tibia respectively in translation and in rotation, and an interface display of data provided by the analysis system.

2 - Measuring device for the characterization of a lesion of the anterior cruciate ligament of the knee (ACL) of a patient according to claim 1 characterized in that it comprises a first motor (9b) controlling the translation of the organ of thrust (9a) and a second motor (12) controlling rotation of the foot support (11b).

3 - Measuring device for the characterization of a lesion of the anterior cruciate ligament of the knee (ACL) of a patient according to the preceding claim characterized in that it comprises a computer memory for recording at least one digital model effort and a computer controlling said motor (9b and 12) by applying control laws functions of the content of said computer memory.

4 - Measuring device for the characterization of a lesion of the anterior cruciate ligament of the knee (ACL) of a patient according to claim 1 characterized in that said second member for positioning a said second sensor (14b) is arranged in a said leg piece (14a).

5 - Measuring device for characterizing a lesion of the anterior cruciate ligament of the knee (ACL) of a patient according to claim 1 characterized in that the first positioning member of the first sensor (15a) and a said second member of positioning of a said second sensor (14b) are mounted on at least one articulated bracket (15b) which is fixed to the plate (17a).

6 - Measuring device for the characterization of a lesion of the anterior cruciate ligament of the knee (ACL) of a patient according to claim 1 characterized in that it is further provided with an assistance device at least comprising a signal transmitter suitable for indicating to a practitioner a correct positioning of the first sensor (15a) and/or of the second sensor (14b) on a specific patient, with regard to reference positions (15b and 14a) respectively of the first sensor (15a) and/or of the second sensor (14b) on the patient previously defined and stored in a second directory of positions of individualized sensors for various patients via a second memory of the assistance device.

7. Apparatus according to any one of the preceding claims, characterized in that the control member comprises a second control module for at least one configuration of the seat (1) for a specific patient, the second control module being a servo module correlated with at least a third motor (4) for positioning in relative inclination between the seat (18) and the backrest (19), of a fourth motor (7) for positioning in relative inclination between the plate (17a) and the seat (18), the second control module comprising a third memory of storage of a third directory of seat configuration models (1) individualized for various patients which are previously established and which are reproducible by the control unit.