Multi-joint device for objective measurement of laxity and cartilage damage

Abstract

The present application discloses a medical device useful for the diagnosis and/or treatment follow-up of human joints, in particular a device for positioning human joints for CT-scan and MRI. The medical device allows an accurate and comprehensive assessment of human joints, characterizing quantitatively biomechanical consequences, whole joint kinematics alterations, cartilage mechanical behavior under pressure and clinical susceptibility to further damage.

Claims

1. A device for facilitating measurement of laxity of a human joint with an imaging equipment, the device comprising: a first part, adapted to receive and hold a thigh, the first part including one or more first belts adapted to hold the thigh; a second part adapted to receive and hold a portion of a leg; a first element attached to the second part, the first element adapted to cause movement of an anterior zone of the leg; a second element attached to the second part, the second element adapted to cause movement of a posterior zone of the leg; a third part adapted to receive and hold a foot, the third part including one or more second belts; and at least one third element attached to the third part, the at least one third element adapted to cause rotational movement of the third part in a first angular direction and in a second angular direction.

2. The device according to claim 1 further comprising a force actuator adapted to cause one of: an external or internal rotation of a patella parallel to a coronal plane; a lateral or medial translation of the patella parallel to the coronal plane; or a lateral or medial tilt of the patella relative to the coronal plane.

3. The device according to claim 2 further comprising a second force actuator arranged to cause a lateral or medial tilt of the patella relative to the coronal plane, wherein the first force actuator is arranged to cause a lateral or medial translation of the patella parallel to the coronal plane, wherein said second force actuator is configured to actuate only after the first force actuator is actuating.

4. The device according to claim 1 wherein first element is disposed on a first inner wall of the second part and the second element is disposed on a second inner wall of the second part.

5. The device according to claim 1 comprising at least one scale disposed in one of the first part, the second part, and the third part, the scale adapted to a position or angle of a first body part relative to a second body part.

6. The device according to claim 1, wherein one of the first element, the second element, and the at least one third element comprises an inflatable element.

7. The device according to claim 6, wherein the inflatable element is one of a hydraulic inflatable element, a pneumatic air cylinder and an inflatable bag.

8. The device according to claim 1, wherein the first and second parts are coupled by a plurality of sliding lockable joints adapted to be locked by tightening nuts.

9. The device according to claim 1 further comprising a flat base attached to the first and second parts, the flat base being adapted to provide support and stability in a horizontal plane to the device.

10. The device according to claim 1, wherein the imaging equipment is one of a computed tomography scan device and a magnetic resonance imaging device.

11. The device according to claim 1 wherein the device comprises one of polymers, resins, composites, and mixtures thereof.

12. A magnetic resonance imaging device comprising the device of claim 1.

13. A method comprising: using the device of claim 1 to measure one of hip internal-external rotation and proximal-distal translations, tibial anterior-posterior translation, internal-external rotation of a knee, medial-lateral patella translation, medial-lateral patellar tilt, internal-external patellar rotation, varus and valgus talar tilt within an ankle joint, anterior-posterior translation of a foot, inversion and eversion of a foot and multi-axis coaptation of a joint.

14. A computer axial tomography device comprising the device of claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The following figures provide preferred embodiments for illustrating the description and should not be seen as limiting the scope of invention:

(2) FIG. 1device diagrams of the movements applied to the (a) hip and knee and (b, c) patellofemoral joints and (d) foot and ankle joints, provided by the device;

(3) FIG. 2schematic representation of a preferred embodiment where it is represented a perspective view of the device for thigh, leg and foot anatomic segments, thus knee and ankle joints, and patella;

(4) FIG. 3schematic representation of a preferred embodiment where it is represented a front view of the device for thigh, leg and foot anatomic segments and patella.

(5) Wherein the reference numbers refer to: (1) represents a device for measuring the instability of human joints, in particular knee and patellofemoral, foot and ankle joints; (2) represents a part for posterior support and fixation of the thigh; (3) represents a part for posterior support and fixation of the leg; (4) represents a supporting piece; (5) represents a part for posterior-plantar-lateral support and fixation of the foot; (6) represents moving parts with flat bases; (7) represents articulation elements; (8) represents a removable part for posterior and front fixation of the leg; (9) represents a removable part for positioning onto the patella; (10) represents a removable part to adjust the means to each patient (15) and the removable part for positioning onto the patella (9); (11) represents a removable supporting part; (12) represents sliding elements to adjust the device to the leg length of each patient; (13) represents means to execute the rotational movements of the ankle and the foot in clockwise and anticlockwise direction; (14) represents means to push the foot forward; (15) represents means to push the patella medially or laterally and/or to tilt the patella; (16) represents means to push the leg posteriorly and anteriorly; (17) represents means to adjust and support the removable supporting part (11); (18) represents tightening nuts for the moving parts (6), for the articulation elements (7) and for the removable supporting part (11).

DESCRIPTION OF EMBODIMENTS

(6) The present application discloses a medical device useful for the diagnosis and/or treatment follow-up of human joints. Specifying some applications, the medical device is useful for accurate and direct quantification of hip, knee and patellofemoral, foot and ankle joints dynamic and/or static laxity i.e., abnormal movement patterns of the referred injured joints, as well as for the evaluation of their cartilage mechanics through coaptation. This medical device is MR and CT-scan Safe and MR Compatible allowing in the scope of human joints the quantification of ligaments and cartilage damage. The present device allows measurements of static and/or dynamic joint laxities in all planes and axes of motion; static laxity is measured involving only one degree of freedom of the joint, whereas dynamic laxity measurements consider the whole joint kinematics. Additionally, the device enhances the visualization and measuring of bone morphometrics and soft tissues (eg.: femur and its trochlear groove depth).

(7) As can be seen in FIGS. 2 and 3, a particular embodiment of the device for measuring human joints (1) described is comprised by parts, namely a part for the posterior support and fixation of the thigh (2), a part for the posterior support and fixation of the leg (3), a supporting part (4) and a part for posterior-plantar-lateral support and fixation of the foot and ankle (5).

(8) These parts may respectively include multiple belts, not represented in the figures, which together with additional parts (8) ensure that the leg, thigh and foot lay and remain fixed against the device (1). Other restraining means are also possible, as straps, girdles, fasteners, cuffs, clamps, or removable parts.

(9) The device comprises at least two actuator push elements placed in opposite sides of the anatomic segment to be actuated, said actuator push elements being arranged to actuate independently. Independently of the human joint to be measured, the force actuators are equal to each other.

(10) To ensure that the images obtained with the device (1) by imaging equipment, in particular by computed axial tomography scan or magnetic resonance imaging, do not show distortions, all materials used in the device are not ferromagnetic, preferably polymers, resins, composites, among others.

(11) The device (1) comprises independent means (16) to push backwards or forward, towards the leg, respectively the anterior or posterior zone of the leg, shown in FIG. 2, respectively located in the inner wall of a part (8) for posterior or anterior support and fixation of the leg. One or both parts are preferably removable.

(12) The device also includes a part for positioning the device onto the patella (9) containing means (15) to push the patella medially or laterally and/or to tilt the patella and/or to rotate the patella, which are adjusted and supported by the parts (10 and 11) attached on the articulation elements (7) in particular through tightening nuts (18), as shown in FIG. 2, allowing to test the patellar movements in any position of the articulated device.

(13) Example measurements of clinical relevance of the patellofemoral joint include measurements of both angles and displacements caused by the force means of the present device, as is detailed further below. This also applies to other jointsthe layout and design of the presently disclosed force means enable the evaluation of joint laxity in both angles and displacements, thus making possible measurements that improve the observability of relevant clinical circumstances.

(14) The displacements the device promotes by applying pressure also allow better distal femoral epiphyseal and patellar morphometric measurements, such as trochlear groove depth, crossing sign, lateral trochlear inclination, trochlear facet asymmetry, by exposure of bone landmarks and soft tissues ability to restraint motion is also measured in the scope of diagnosis and or clinic follow-up after conservative or surgical treatments.

(15) On the other hand, in the foot zone (4), as can be seen in FIG. 3, the device also comprises means (13) that are able, respectively alternating through vertical and horizontal shafts, to push the foot and to push the ankle, in multiplanar motions, in clockwise and anti-clockwise direction, as well as means (14) to push the foot forward and backward, strategically located into the support piece (4).

(16) These means (13, 14, 15 and 16), denominated actuators, to move their respective foot and ankle, patella and leg zones, so as to position and hold the patient foot and/or patella and/or leg into position, can be of any suitable kind, namely manually inflatable bags or compressor filled ones, or by hydraulic means, or by spring-loaded elements, and can work independently and alternatively from each other.

(17) The device allows the release of the actuators in order to the accurate and safe application of the test, preventing the application of excessive force onto the anatomical structures.

(18) Moreover, the means (16) to push their respective leg zones can work in conjunction with the means (13) to push the foot, so as to position and hold the foot and/or the patient's leg into position. This combined movement is an advantageous feature of the device. It is also an advantageous feature of the device to make it combined simultaneously with a MRI or CT-scan equipment.

(19) Thus, as described, the device can position, hold and move the foot and/or the patella and/or the leg and/or the thigh of the patient in various positions, from 10 to 500 degrees of knee flexion.

(20) The measurements performed with the device (1) include the evaluation in mm and/or degrees of translation and/or rotation into the MRI or CT-scan device, or any other imaging device that permits these measurements. These measurements are normally taken with no pressure and then with pressure, wherein a certain loading is applied on a given anatomic segment, considering the bony landmarks of its respective joint. It is important to refer that from the movements induced by the present device combined with the compatibility with imaging devices, one can get more than a single measurement: taking in consideration the example of the patellofemoral joint evaluation, from a loading applied on the medial facet of the patella along the medial-lateral axis (lateral patellar translation), one can measure either its lateral displacement considering the distance from the medial edge of the patella to a line drawn perpendicular to the posterior condylar line and passing through the most anterior point of the medial femur condyle; either its lateral tilt considered as the angle between the posterior condylar line and a line drawn through the maximum width of the patella. Similar procedure is translated to the other referred joints, in order to characterize the whole joint's movements.

(21) The device is manually or automatically placed over the examination table of the MRI or CT-scan equipment. Through the visualization of the MRI or CT-scan images, one can evaluate the condition of the tissues that ideally resist dislocation and promote alignment of the anatomical structures of the mentioned joints.

(22) The device (1) includes scales to initially indicate the position of the leg and/or patella and/or foot, both in mm and/or degrees of translation and/or rotation.

(23) In the device, the parts of the leg and thigh can be positioned at different angles between their own, in particular comprised between 10 and 50 degrees, through the articulation elements (7) held in the desired positions by suitable means, for example tightening nuts (18), clamps, ratchets. The parts of the leg and thigh can also be adapted to various anatomical dimensions of the patient by sliding said elements (12) and parts (2, 3 and 4) which are then fixed in the desired positions by mechanical fixing means, not represented in the Figures, placed in openings or holes existing in those elements and parts. Through the same sliding system, the piece (9) for positioning onto the patella, removable part (9) and supporting part (10) can identically be adapted to various anatomical dimensions of the patella of each patient, as well as to different anatomical positions of the patella on the patient's knee and also to the various positions of the device through the articulated elements (7).

(24) In FIGS. 2 and 3 one can see the moving parts (6) comprising flat bases which will provide support and stability to the device (1) on a horizontal plane. These moving parts (6) are fastened to the sides of parts (2) and (3) through tightening nuts (18).

(25) The disclosure is of course not in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof without departing from the basic idea of the disclosure as defined in the appended claims.

(26) The above described embodiments are obviously combinable.

(27) The following dependent claims set out particular embodiments of the disclosure.