FR2784893A1 - MOUTH OF MOBILIZATION OF A LOWER MEMBER - Google Patents

Abstract

The splint has a base (1) which supports an articulated structure (4) which has leg segments (9,5) connected by motorised and plain joints (20,10). A rail (19) allows horizontal movement of the structure and a footrest (17) supports the patient's feet. The footrest is mounted on the lower leg segment of the structure (9) by rods which slide in tubes (11) and are sprung internally or externally to return to a position of least extension

Description

 The present invention relates to the medical field and relates to equipment used for orthopedic treatments or functional rehabilitation of the lower limbs. For the above purposes, the proposed equipment is generally constituted in the form of a splint comprising a base or base supporting an articulated structure composed of a segment or crural cradle connected by an articulation to a segment or cradle cradle most equipped often, like the crural cradle, a hammock for receiving and supporting the corresponding part of the lower limb to be mobilized.

 Such splints, called articulated as opposed to fixed splints allowing only immobilization in determined posture of a lower limb, are intended to allow mobilization in flexion-extension at least for two of the joints of a lower limb, namely coxofemoral joint and knee.

 To this end, provision is generally made for mounting the end of the cradle on a carriage which is movable along a longitudinal axis of the base or of the base. By such an arrangement, it becomes possible to control the alternating sliding of the carriage either directly by the physical action of the lower limb, or indirectly by means of a motor acting independently.

 This last type of material is generally qualified as passive mobilization splint, since it is responsible for causing flexion and extension of the lower limb without the muscular systems of the latter being responsible for such movement.

 Such so-called passive mobilization splints have brought great progress in rehabilitation methods and should be considered as generally satisfactory.

 However, the putting into practice of such materials has made it possible to note a non-optimal flexion-extension functionality in certain applications or implementations.

 In fact, depending on the types of equipment and / or the use put in place, it is frequent to observe that the axis of articulation of the crural segment on the base or the base is not located in exact coincidence with the anatomical axis of the coxo-femoral joint. It is frequent to note a plane offset with respect to that of the base support, but also an offset in the same plane.

 Such a non-coincidence has a consequence which is that the effective length of the crural segment between its articulation on the base and the axis of articulation with the leg segment, appears of length greater than that of the osseous segment of the member to be reeducated and, more in particular, the length of the femur between the coxofemoral axis and the knee.

 The consequence of such non-identity is that, from a flexion situation, for example of the order of 90 and in which it could be considered that the knee joint and the joint between the crural and leg segments are substantially coincidentally, any displacement in extension results in a shift between the trajectories in arcs of a circle described by these points of articulation.

 This results in an absence of support between the foot and the footrest and rehabilitative conditions which, due to this consequence, are no longer optimal and induce disorders and constraints which are not favorable for obtaining the result. research.

 The problem therefore arises of being able to propose a solution overcoming this difficulty so that, by construction, this drawback can be remedied, in order to be able to properly mobilize a lower limb without giving rise to induced fatigue which negatively counterbalances the rehabilitative results obtained by commissioning of such a splint.

 The object of the invention is to propose a constructive solution which precisely makes it possible to solve the problem thus posed.

 The means according to the invention are particularly designed to meet, in addition to the above problem, a second requirement frequently imposed on the personnel responsible for the commissioning of such splints and which is that of the need for power or duty adjust the length of the leg segment according to the length of the corresponding bone segment of the limb to be rehabilitated.

 The object of the invention, by the means used to resolve the above problem, opens a possibility of automatic adjustment of such a length.

 The object of the invention is also designed to take account of a finding frequently made in the field of rehabilitation, when the functional rehabilitation treatment, following a trauma of great importance, leaves the lower limb in a passive level of work not involving any voluntary muscular solicitation, mainly in the thigh muscles.

 In such a case and if the rehabilitative treatment must take place for a relatively long time, it is frequent to note a significant loss of the muscular possibilities of the quadriceps group which must then be considered to rehabilitate by other means to restore the patient to voluntary contraction reflex, as well as anterior muscle power.

 The object of the invention is precisely to choose technical means which, if necessary, can be used to provide a first type of response to such a finding, without having the pretension of being able to constitute a substitute for the means of rehabilitation. functional and effective functional of the quadriceps muscles.

 An additional object of the invention is therefore to propose technical means which are able to offer several rehabilitative functionalities which can be considered independently or simultaneously.

 To achieve the above objectives, the mobilization splint of a lower limb, of the type comprising a base carrying an articulated structure composed of a crural segment or cradle articulated at one end of the base and a cradle or leg segment linked to the crural cradle by a hinge pin orthogonal to the direction of a rail defined by the base for guiding the leg cradle, a motor means interposed between the base and the articulated structure for moving the leg segment relative to the rail in an alternative rectilinear movement and a footrest adapted at the end of the leg cradle or segment opposite the crural cradle, is characterized in that, according to the invention, said footrest is mounted on the cradle cradle by means of at least one slide with the interposition of an elastic return means always tending to bring the footrest into a position of least extension relative to the cradle cradle.

 Various other characteristics will emerge from the description given below with reference to the appended drawings which show, by way of nonlimiting examples, embodiments and implementation of the subject of the invention.

 Fig. 1 is a schematic perspective of a lower limb mobilization splint.

 Fig. 2 is an explanatory diagram highlighting the fundamental problem that the object of the invention aims to solve.

 Fig. 3 is a partial sectional elevation showing, on a larger scale, a detail of constructive embodiment of the splint according to FIG. 1.

 Fig. 4 is a sectional elevation, on a larger scale, illustrating an alternative embodiment.

Fig. 5 is a partial sectional elevation, partially cut away, showing, on a still larger scale, another embodiment of the means according to the invention
Fig. 1 shows a so-called passive mobilization splint of a lower limb which can be either a right limb or a left limb, given that the illustrated splint reveals a symmetrical construction.

 The splint includes a base or base 1 which is intended to rest on a support surface, such as 2, of any suitable nature and advantageously constituted by the mattress of bedding.

 The base or base 1 comprises a proximal part 3 with which it supports an articulated structure 4 composed of a crural segment or cradle 5 connected by a hinge 6 to the proximal part 3. The crural segment 5 is composed of two longitudinal members or the like 7 possibly interconnected by a spacer and even being fitted with a flexible element for supporting the thigh of a lower limb, for example, a hammock 8 made of any suitable material.

 The structure 4 is also composed of a leg segment 9 which is articulated in the extension of the crural segment 5 by means of trunnions or pivots 10 which define between them a pivot axis x-x 'which is orthogonal to the direction general of the base or the base 1.

 The leg segment 9 is constituted by two longitudinal members or the like 11 possibly connected by a transverse spacer 12 and also capable of being fitted with a flexible support mattress, such as a hammock 13.

 The end portion of the leg segment 9 opposite the pins 10 carries a footrest 14 consisting of a support 15 possibly adjustable in orientation along an axis y-y 'substantially parallel to the axis x-x'. The support 15 carries a sole 16 which can be adjusted in orientation in the double direction of the arrow f1 by means of any suitable means known in the art, making use, for example, of a pivot and a tightening button. The plate 16 carries a sole 17 possibly adjustable in the double direction of the arrow f2 and, preferably, made in the form of an open shell to allow the establishment and support of the foot of the lower limb to be rehabilitated.

Finally, the structure 4 is carried at the level of the leg segment 9 by a carriage 18 supported by a guide track 19 materialized by the base or the base 1 in a rectilinear direction which is orthogonal to the axis x-x '
The structure 4 is associated with motorization means, such as those designated by the general reference 20, to act on the structure so as to control a movement of the carriage 18 in alternating rectilinear travel on the track 19 to drive the structure 4 from of a complete extension in a flexion movement and vice versa, as is known to those skilled in the art. It must be considered that the motorization means 20, which can be controlled from a remote control unit 21, can be adapted on one of the pivots 10 or even be placed in relation to the carriage 18 by involving then an appropriate transmission.

 The choice of such motorization means does not fall directly within the scope of the invention and are accessible to those skilled in the art.

 A mobilization splint of the above type generally, or at least, frequently occurs during its installation, a situation of the type illustrated in FIG. 2, in which by sliding, inadvertence or impossibility of positioning, the articulation 6 between the crural segment and the base 1 is not in coincidence with the coxo-femoral articulation 22 of the member 23 to be rehabilitated.

 Such a situation also involves a length of the crural segment 4 which is different from the length of the femoral articular segment of the limb 23, so that two types of offset can occur between axes 6 and 22, namely an offset N relative to the plane of the base and an offset n in a plane perpendicular to this plane.

 This absence of coincidence translates automatically during an extension-flexion movement by trajectories tl and t2 which are different for the axis x-x 'and for the knee 24 to which normally this axis x-x' must correspond.

 The difference between the trajectories tl and t2 can be variable but, in all cases, results in non-optimal functional conditions.

 Fig. 2 clearly shows that the offset of the trajectories tl and t2 has the consequence that, in the extended position, the knee trajectory t2 is located behind the trajectory tl relative to the distal end of the base and that, by thereafter, the footrest 17 gradually disappears forward relative to the foot which is no longer supported nor, if necessary, supported.

 The object of the invention is to propose means which make it possible to compensate for this progressive deviation during the trajectory, so as to restore, over the whole trajectory, a support between the foot and the footrest 17, whatever the difference between the trajectories tl and t2.

 To this end, as illustrated in FIG. 3, provision is made to mount the support 15 carrying the plate 16 and the footrest 17, on at least one rod 30 and, preferably, two, which are arranged so that they can slide telescopically inside at at least one and, preferably, the two side members 11, which are in this regard, at least in part, tubular. Each rod 30 is provided with an end collar 31 and slides in a tubular plug 32 closing the distal end of the spar 11, so as to constitute a sliding bearing for the rod 30. The spar 11 delimits a blind bore which defines with the rod 30, an annular interval 33 capable of receiving an elastic return member 34 constituting a means always tending to act on the rod 30, so as to urge it in the direction of the arrow f3 to give it a position of least extension relative to the spar 11. Such a position of least extension is, for example but not exclusively, determined by the supply bearing the collar 31 on the bottom of the bore of the spar 11. The elastic members 34 are advantageously constituted by springs helical placed under compression stress.

 The plug 32 can be in the form of a smooth bearing, or even a ball bushing and is fitted on the end of the beam 11, advantageously removable to facilitate the mounting of the rod 30, as well as that spring 34.

 By resting on fig. 2, it can be seen that the adaptation of the splint to the member 23 to be mobilized takes place in a position of initial presetting of flexion, for example at 90, in which the existence of a pseudo coincidence can be considered between axis x-x 'and axis 24 of the knee. In such a position, the useful length between the axis x-x 'and the axis y-y is adjusted, for example, by means of the position of the support 15 on the rods 30, in such a way that it is less than the length of the tibial segment 25 of the lower limb 23, so that in this position, the footrest 17 is urged in partial extension stroke against the antagonistic action of the spring or springs 34 which are subjected to a stress greater than that which they undergo in the position of least extension, as mentioned above.

During the extension movement requesting the articulated structure in the direction of arrow 4, the offset between the paths t, and t2 shows that the one t2 followed by the knee 24 tends to lag behind that tl followed by the axis xx '
Ordinarily in such a situation, this results in a withdrawal of the foot relative to the footrest 17, so that the third point of support initially sought is reduced or even eliminated.

 On the contrary, according to the invention, the delay taken by the path t2 causes a retreat of the foot which is faithfully followed by the footrest 17 urged in the retraction race and of lesser extension by the spring or springs 34, the preload of which origin was accentuated by the adjustment carried out as said previously.

 Fig. 4 shows that it may be advantageous to constitute the plug 32 in the form of a smooth or ball bearing, adjustable, for example by thread-tapping, in the direction of the arrow 5 relative to the spar 11.

 Such an adjustment makes it possible, when it is desirable, to modify the restoring force of the spring 34 and to envisage, for example, using the means according to the invention to offer a possibility of active mobilization which would be voluntarily maintained by the patient to cause the footrest 17 to recede against the antagonistic action of the spring or springs 34, so as to stress the muscular function of the quadriceps.

 It should be considered that such a possibility is more fully offered when it is possible to adjust the nominal length of the leg segment 9 by means of the means for fixing and mounting the support 15 on the rods 30, for example at by means of tightening knobs 35.

 Fig. 4 shows that in certain cases, it may be advantageous to provide a possibility of adjusting the abutment position in a lesser extension, other than by bringing the collar 31 to bear on the bottom of the bore of the beam 11.

 Such a possibility of adjustment, as illustrated in FIG. 4, can intervene by a nut 36, for example formed by two half-collars assembled by a deformable hoop 37 elastically forcing the half-collars to occupy a tightened state on the rod 30 in an axial immobilization position in which each half -collar is engaged by a rib 38 in notches 39 of a series presented axially by the rod 30.

An alternative embodiment of such a means is illustrated in FIG. 5 in
which the tubular proximal part of the spar 11 has one or more series of
holes 40 allowing the engagement of a pin 41 on which comes to bear the
collar 31.

In addition to the two functions likely to be assumed by the means described
above, it should be noted that the possibility of telescopic sliding at
elastic return to footrest 17, provides an automatic adjustment adjustment to
the length of the tibial segment of member 23 to be rehabilitated, without it being absolutely
necessary to make a specific adjustment by the buttons 35 when by default, such
nominal length setting is chosen below the length of said segment.

Fig. 1 highlights a simplified embodiment of the means
according to the invention. According to this variant, each rod 30-spar 11 assembly is
associated with an elastic return means constituted by a spring 34 which is interposed
under prior stretching constraint between an anchoring ring 42 carried by the rod 30,
see the support 15, and a bar with holes 43 carried by the beam 11 near the
pin 10.

The members 34 can be springs of all appropriate types and,
in particular, elastic cables of the type of those known commercially under the
name of SANDOW. A variant may also consist in replacing the springs
helical in fig. 3 by elastic cables housed inside the rods 30 which are
then tubular, and so that one of the ends is integral with said rod,
while the other is linked to tube 11.

 Such simpler and less expensive means offer a possibility of adaptation to the will of the user and confer the same functional characteristics as those described above.

 The invention is not limited to the examples described and shown, since various modifications can be made thereto without departing from its scope.

Claims (10)

CLAIMS:  1-Mobilization splint of a lower limb, of the type comprising a base (1) carrying an articulated structure (4) composed of a crural segment or cradle (5) articulated at one end of the base and of a cradle or leg segment (9) linked to the crural cradle by an articulation axis (x-x ') orthogonal to the direction of a rail (19) defined by the base for guiding the cradle cradle, a motorization means ( 20) interposed between the base and the articulated structure for moving the leg segment relative to the rail in an alternating rectilinear movement and a footrest (17) adapted at the end of the leg cradle or segment opposite the crural cradle,  characterized in that said footrest is mounted on the cradle cradle by means of at least one slide (11,30) with the interposition of an elastic return means (34) always tending to bring the footrest into a position of lesser extension relative to the cradle.  2-splint according to claim 1, characterized in that the elastic return means is attached externally.  3-splint according to claim 1, characterized in that the elastic return means is included in the slide.  4-Splint according to one of claims 1 to 3, characterized in that the elastic return means is associated with a member (32) for adjusting its return force.  5-Splint according to one of claims 1 to 4, characterized in that the elastic return means is completed by a member (36 or 41) for adjusting the stop position in the least extension of the footrest.  6-splint according to one of claims 3 to 5, characterized in that the elastic return means is constituted by a helical spring (34) threaded concentrically on a rod (30) mounted telescopically in a beam (11) at least in tubular part of the cradle (9), said spring being mounted under stress between a collar (31) of the rod and a tubular plug (32) adapted on the beam to form a sliding bearing of the rod.  7-splint according to claim 6, characterized in that the pedal cap is adjustable in axial position relative to the beam to constitute the means for adjusting the force of the spring.  8-splint according to claim 5, characterized in that the member for adjusting the stop position is constituted by an adjustable stop (36) adapted between the rod and the spar.  9-splint according to claim 8, characterized in that the adjustable stop is constituted by a pin (41) passing through one of a series of holes (40) made in the beam to form a support for the collar of the rod .  10-splint according to claim 8, characterized in that the adjustable stop consists of a nut (36) with elastic opening adapting to a series of notches or the like (39).