WO1991004715A1

WO1991004715A1 - Femoro-patellar prosthesis and its devices for setting in place

Info

Publication number: WO1991004715A1
Application number: PCT/FR1990/000691
Authority: WO
Inventors: Georges Mendolia
Original assignee: Georges Mendolia
Priority date: 1989-09-29
Filing date: 1990-09-26
Publication date: 1991-04-18
Also published as: AU6518390A; FR2652497B1; FR2652497A1

Abstract

The invention relates to a femoro-patellar prosthesis comprised of a trochlear element and of a rotulian element intended to be fixed respectively to the lower femoral extremity and to the patella after having done the corresponding resections. The trochlear element (10) is essentially comprised of a semi-circular curved groove (11) integral with a sole (12) of which one of the extremities has a securing orifice (121) and of which the other extremity is prolounged, in the medial plane, by a semi-cylindrical inclined heel (13) provided with a transverse shaft (14) arranged parallel to the sole (12) in the medial plane thereof and oriented towards the securing orifice (121). The rotulian element (30) has on the bearing face of its medallion (31) and at the periphery of its implantation post (32), incrustation scores and recesses.

Description

Femoro-patellar prosthesis and its positioning devices.

The invention relates to a femoro-patellar prosthesis and its delivery devices.

It is often necessary to interpose, between the kneecap and the femur, a so-called femoro-patellar prosthesis intended to ensure the reconstruction of the corresponding joint.

This reconstruction was obtained, until then, by placing in place - using a very artisanal process inspired by the techniques used in cabinet making - of a femoral prosthesis, called "trochleen element", on the femoral trochlea, and a patellar prosthesis, called "patellar element" or "medial", on the oteus; Implantation being carried out by nailing or screwing, with or without interposition of cement, as described in document FR-A-2,521,421, which corresponds to the preamble of claim 1.

It resulted from this situation a fairly low success rate, mainly due to excessive and poor bone resections which caused articulation problems, greatly annoying the people concerned and causing them, suffering that was difficult to bear, constituting a handicap. permanent which justified successive interventions which most often only worsened the situation.

The object of the present invention is to remedy these drawbacks. This invention, such as it is characterized, solves the problem of creating a prosthesis and its placement devices making it possible to perform, without any trial and error, on the femoral trochlea and on the ro tule, the bone resections adapted exactly to the shape and dimensions of the corresponding prostheses, by ensuring a rigorous positioning of the elements constituting the prosthesis and of this relative to the leg-ankle-head-femur alignment, in particular ensuring, on the trochlean surface, very precise sections strictly parallel to the posterior bi-condylar axis, of profile strictly parallel to the axis of the femur, and, on the patella, a precise and plane section corresponding exactly to the thickness of the medallion of the patellar prosthesis.

The femoro-patellar prosthesis according to the invention, consisting of a trochIean element with a curved semi-circular groove and a patellar element with a semi-spherical medallion of corresponding radius, intended to be fixed, respectively, on the lower femoral end , by nails and screws, and on the ball joint, by implantation stud, after execution of the corresponding resections, is characterized in that the curved semi-circular groove of the trochlear element is integral with a sole whose end comprises a fixing orifice and the other end of which is extended, in the median plane, by an inclined semi-cylindrical heel provided with a rod arranged parallel to the sole in the median plane thereof and oriented towards the fixing orifice , and in that the rotuiian element comprises, on the bearing face of its medallion, circular inlay recesses connected radially by grooves and, at the periphery of its contact pad plantation, inlay streaks connected transversely by notches.

The devices for placing the femoro-patellar prosthesis are characterized in that: 1) The devices for placing the trochlear element include: - a davit, mainly consisting of a plate at the base of lacquerIe are fixed euiIIères with spacing and adjustable lateral positioning, in the plane of symmetry of IaqueIle is made a bore communicating laterally by grooves with the front and rear sides era of the plate, in which the axis is mounted comprising, towards one of its ends, a drilling guide orifice, towards the other end another orifice provided with an alignment rod, and towards its middle, a cutting guide surmounted by a feeler arm; the drilling guide hole, the alignment rod and the feeler arm being located in the same plane, while the cutting guide is located in a perpendicular plane, - a milling template consisting of a fixing plate, provided fixing orifices, soIidaire of an inclined tubular milling guide, indented longitudinally in its part located under the fixing plate, on the side thereof, and comprising, at its base, a stud forming a stop,

- a milling cutter, called a "tréfine", made up of a hollow cylindrical part, partially indented, comprising, at one of its ends, cutting teeth and, at the other end, a circular heel surmounted by a tail drive.

2) The devices for fitting the rotuIary element include:

- a davit consisting mainly of two arms joined and held parallel to each other by means of an articulated crossover equipped with a spring permanently reminding one of the arms against a knurled nut mounted on a solid threaded graduated rod of the other arm; The said arms being provided, at one of their ends, respectively ment of a cylindrical square threaded and graduated, axially drilled, on which slides a cutting guide consisting of a split bell connected by a smooth ring, provided with a circular lip, with a knurled nut, made in two parts, comprising a groove intended to receive the lip of the ring of the bell, of a sliding sliding cup having in its center a pointed lug,

- a centering template consisting of a drilled cylindrical part, comprising a circular base provided with anchoring points,

- a drill bit for drilling the implantation hole of the nipple for fixing the rotatory element of the prosthesis, consisting of a heel drill bit surmounted by a drive shank,

- a jaw fitting on the base of the bell intended to facilitate the implantation by clamping the rotuIien element.

The means for adjusting the spacing and positioning of the cookers of the trochlear davit is obtained by means of a dovetail groove made at the base of the plate, of pins of the same shape, located at the base of the spoons, and a threaded rod, with two opposite threads, fitted with a knob.

The probe arm, equipping the trochial cutting guide, has a square-shaped end, pierced in the middle, the base of which is situated in a plane perpendicular to the support axis coinciding with the upper face of the cutting guide. The zero graduation of the cy li ndr i square that is threaded, supporting the cup guide bell, corresponds to a resection medium (9 mm).

The advantages obtained thanks to this invention consist mainly in an anatomical positioning in the three planes of space; minimal bone resection with a simple geometry cut; a thickness of the implant identical to the resection; an easy, precise and calculated miIMimetric cut; a guided rotuiian course from flexion to full extension; a large bearing surface ensuring excellent load distribution; a double fixing, by sceIIement and screw; compatibility with all other single-compartment femoral-tibial prostheses. Other characteristics and advantages will appear in the description which follows of a prosthesis and of its implementation devices made according to the invention, given by way of nonlimiting example with regard to the appended drawings in which:

- Figure 1 shows a longitudinal sectional view of a lower end of the femur fitted with trochIean and patellar prostheses, - Figure 2 shows a front view of a femur head fitted with the troch I éenne and ro tu prostheses link,

FIG. 3 represents a bottom view of the trochlear prosthesis,

- Figure 4 shows a perspective view of the piercing and cutting guide of the trochlea, in place on a lower end of the femur, - Figure 5 shows a side view of the piercing and cutting guide of the trochlea in place on a lower end femur laugh,

FIG. 6 represents a partial bottom view of the guide for piercing and cutting the trochlea,

- Figure 7 shows a side view, in section, of a femur head provided with the milling template equipped with its wire, in place in the inter-condylar notch, - Figure 8 shows a top view of a lower end of the femur provided with the milling template equipped with its trine in place in the inter-condylar notch,

FIG. 9 represents a side view in partial section of the guide for cutting and drilling the ball joint,

FIG. 10 represents a side view in partial section of the cutting and drilling guide of the IarotuIe in place on a ball joint before cutting and drilling,

FIG. 11 represents a view in partial section of the cutting and drilling guide of the patella used for the implantation of the corresponding prosthesis, FIG. 12 represents a bottom view of a prosthesis of large diameter patella,

FIG. 13 represents three views in elevation of a patella prosthesis,

FIG. 14 represents a bottom view of a small diameter ball prosthesis,

FIG. 15 represents a bottom view of a ball joint prosthesis of medium diameter, FIG. 16 represents a bottom view of a large ball joint prosthesis,

FIG. 17 represents a sectional view of the patellar milling device in place on a ball joint,

- Figure 18 shows a partial sectional view of the drilling guide of the axis of the trochIée in place on the lower end of a femur at the time of the drilling operation.

By examining FIGS. 1 to 3, it can be seen that the femoro-patellar prosthesis consists of a trochleen element 10 comprising a curved semi-circular groove 11 forming a body with a sole 12, one of the ends of which has a fixing orifice 121 by a screw 2 and the other end of which is extended, in the median plane, by an ineIined semi-cylindrical pin 13 provided with a transverse rod 14 disposed parallel to the sole 12, in the median plane of the latter, and a patellar element 30 consisting of a medaiIIon 31 and an anchoring pad 32.

The sole 12 rests on a flat surface, resulting from a bone resection carried out according to a cut in the plane X of profiI strictly parallel to the axis XX of the femur 40 and perpendicular to the posterior bi-condylar axis 22. The rod 14 enters an orifice 41 previously drilled in the intra-condylar space 42, parallel to the axis XX of the femur 40.

Referring to Figures 4 to 6, it is noted that the anterior cutting guide davit 50 consists of a plate 51 having, at its base, a dovetail groove 511 in which slides, under the action of a rod 52 with two opposite threads 521 and 522 and a knurled button 53, the heel in the shape of a tenon 541 of two cutters 542 and 543, intended to bear on the posterior condyIes 43 and 44, and, in its median plane, a bore 512, provided with grooves 513, in which is mounted, free in translation and in rotation, an axis 55 comprising, at its base, a transverse drilling guide orifice 551 for orifice 41, at its upper part, an orifice 552 intended to receive a removable guide rod 56, and, towards its middle, a cutting guide 57, materializing the cutting plane V, surmounted a feeler arm 58 provided with a finger 581 pierced with an orifice 582 into which a fixing nail 583 penetrates.

Thus, as can be seen, the adjustment of the spacing of the spoons 542 and 543 as a function of that of the condyles 43 and 44, followed by the pressing against the said condyles, then the adjustment of the positioning of the plate 51 to the using the guide rod 56, by locating the latter in a plane parallel to the axis XX of the femur 40, makes it possible to determine the cutting plane Y of the bone resection by pressing the finger 581 of the feeler arm 58 on the middle of the femoral shaft, by simple sliding and rotation of the axis 55. The soldering of the forceps at the lower femoral end by means of the nail 583 therefore makes it possible to carry out the bone resection 45 by resting on the face upper 571 of the cutting guide 57.

Now examining FIGS. 7 and 8, it can be seen that the milling template 60 consists of a plate 61 provided with fixing holes 611 by means of points 63, integral with an inclined cylindrical milling guide 62 comprising a longitudinal notch 621 in its part located under the plate 61 and, at its base, a stud forming a stop 622.

Thus, after having positioned the plate 61 on the trochIean bone resection, previously carried out, and fixed the said plate with the aid of the tips 63, it suffices to intro duire the tréfine 70 in the guide 62 then make the chamfer in the intra-condylar space, until the heel 71 of the said cutter comes into contact with the upper end of the guide 62. The cutter 70 has a obviously 72, over part of its height, communicating laterally with the outside by means of a light 73.

Referring now to Figures 9, 10 and 11, it is noted that the davit 80 for cutting the ball 8 consists of two arms 81 and 82, connected and held parallel to each other by means of an articulated cross 83 provided a return spring 831, ensuring the return of the upper arm 82 against a knurled nut 841 mounted on a threaded and graduated rod 840 connected to the lower arm 81. The upper arm 82 has, at one of its ends, a square cylindrical threaded graduated 821, comprising an axial bore 822, on IaqueIle slides the cutting guide consisting of a bell 85 having a lateral slot 851, allowing the passage of the upper arm 82, connected by a smooth ring 852 with lip 853 to a nut thumbwheel 86, made in two parts, comprising a groove 861 receiving the lip 853 from the ring 852 from the cutting guide bell 85. The lower arm 81 is provided, at its end situated under the bell 85, with a cutter removable health 87, comprising, in its center, a pointed lug 871 and, radially, fixing orifices 872 by means of nails 873 on the anterior face of the ball, before the forceps are placed thereon. A mόrdache 88 fits at the base of the bell 85 and makes it possible to exert an axial force on the medaiIlon 31 of the patellar element 30 of the prosthesis to facilitate its complete implantation, by exerting an effort of bringing the arms 81 together and 82 by means of the threaded rod 840 and the knurled nut 841. A graduation, carried on the square, which indicates a zero cut then depths eh mm in addition and in minus, brings the cutting guide bell to a predetermined position which can be reconsidered as appropriate (0 = 9 mm; + = 7 mm; - = 11 mm). The drilling axiaI 822 of the bell holder bracket 821 allows the fixing of the forceps on the ball joint 8 by means of a nail 89.

By examining FIGS. 12 to 16, it can be seen that the patellar element 30 of the prosthesis, although having an implantation pad 32 provided with identical ridges 321 and notches 322, differ as to the diameter of the medallion 31 and, for each diameter, according to the height H of the medallion. Furthermore, depending on the diameter, the circular inlay recesses 311 are 1 or 2 in number. These are connected radially by grooves 312.

FIG. 17 represents the centering template 90 consisting of a cylindrical conduit 91 provided with a circular base 92 provided with anchoring points 93. Thus, to carry out the drilling of the patella after carrying out the bone resection, it suffices to put in place the said template then introduce therein the drill bit 94 provided with a heel 941 and a tail 942 and then drive it in rotation until the heel comes into contact 941 against the upper end of the cylindrical duct 91.

FIG. 18 represents the use of the intracondylar bit 59, comprising a semi-cylindrical ring 591 introduced into the drilling guide orifice 551 existing in the axis 55 of the cutting guide forceps 50.

The method of implanting the femoropateal prosthesis, using the devices designed for this purpose, according to the invention, after having made a large external para-patellar skin incision with incision of the internal flap, so as to offset the skin incision and

The incision opening the joint, and having dislocated the patella outward while keeping the knee in flexion, consists mainly:

1) for the trochlear element, to make a frontal cut along a plane Y strictly parallel to the posterior bicondylar axis 22 of profiI strictly parallel to the axis XX of the femur 40, so as to take into account, on the one hand, the axis of the femur 40 on the profiI and from the front, and, on the other hand, the low femoral rotation which varies from one individual to another, the posterior bi-condyI axis being the reference plane, by doing the following:

- Positioning of the anterior cutting guide davit 50 while ensuring that the euiIlers come to bear on the posterior condy 43 and 44 and that the alignment rod 56 is strictly parallel to the axis XX of the femur 40 on Ie profile, and that the finger 581 of the trap arm 58 is in abutment on the middle of the femoral shaft, with fixing of the latter by means of a nail 583,

placing the intra-condy bit by passing it through the orifice 551 provided for this purpose in the axis 55 supporting the cutting guide 57, the feeler arm 58 and the guide rod 56,

- execution of the anterior trochIean cut by resting on the upper face 571 of the cutting guide 57, thus performing a minimum bone resection (1 to 5 mm at the bottom of the trochlea), well focused and well positioned both from the front and from the profiI , as well as on the rotating pIan; Ie goal being to respect and provide material, only laterally, to guide the patella, without extra thickness at the bottom of the notch of the trochlea, so as not to create any extra thickness likely to cause pain femoro- pasta, - establishment of the milling template 60 on the trochial surface by determining, depending on the width, the prosthesis which best adapts (small, medium or large), - realization of the inter-condy chamfering by resecting, using of the tréfine 70, the just necessary part, of the inter-condylar notch at the implantation of the trochleen element of the prosthesis, - disassembly of the milling template 60 and presentation of the trochleen element 10 of the prosthesis after having regularized, if necessary, the edges of the cut and makes the rod 14 penetrate into the orifice 41 previously drilled, - sealing of the trochleen element 10 and definitive fixing of this by means of a cortical neutralization screw 2 passed through the orifice 121 provided for this purpose in the sole 12 of the prosthesis, in order to apply it perfectly on the surface of the cut.

2) For the patellar element, make a perfectly flat and precise cut so that the thickness of the patellar resection corresponds to the thickness of the medallion 31 of the patellar element 30 so as not to cause excess thickness at the level of the femoro-patellar joint, source of pain and imitation of flexion, or an under-thickness, source of instability of the patella and reduction of the force of extension, by proceeding as follows:

positioning the removable cup 87 of the cutting guide davit 80 in the center of the ball joint 8 on the external part thereof, using the pointed lug 871 and nails 873 passed through the radial holes 872 provided for this; which allows the patella to be luxated by turning it 180 °, - Positioning of the rotuiar cutting forceps 80 by inserting the corresponding arm thereof 81 in the recess provided for this purpose at the base of the sliding island cutter, then bringing the arms 81 and 82 of the forceps 80 closer, by action on the nut 841, until the base of the bell holder square 821 comes into contact with the internal part of the ball joint 8, then securing the assembly by nailing via a nail 89 introduced into the axial hole 822 existing in the bell holder bracket 821.

- determination of the cutting plane by action on the thumb nut 86 for operating your bell 85 while looking for the zero position of the graduation corresponding to an average resection,

- Realization of the rotuiienne cut by resting on the crown located at the base of the bell 85,

- drilling of the implantation orifice of the rotuIian element 30 using the drill bit 94 and the centering template

90 planned for that,

- choice of prosthesis allowing to best cover the surface of the patellar cut, using a small, medium or large size,

- Placement of the prosthesis with the help of the cutting guide forceps 80, after having fitted the base of the bell 85 with the clamping jaw 88, and by screwing the thumb nut 841 ensuring the bringing together of the arms 81 and 82 of the davit 80 until close contact is obtained between the base of the prosthesis medaiIIon and the cutting plane, with cement interposition, - reduction of the patella and re-suturing of the patellar fins. The track first is then closed yaw by plan.

Thus, the trochIean throat was put back very high so as to guide the patella in its complete positioning, taking into account that the arthroses are often very high patella which need to be guided at a distance markedly greater than the height of the trochlea. usual.

As far as the patella is concerned, the patellar cut is perfectly guided by the tick 85 of the patellar cut guide 80, since the latter makes it possible to firmly stabilize the patella 8 during cutting, hence obtaining a perfectly precise cut. plane. The thickness of the patellar resection is, in turn, determined very precisely taking into account, possibly, certain peculiarities, such as the thickness of the cement layer for example, given the presence of graduation on the '' Davit bell holder square, in order to avoid any excess thickness or under-thickness.

Claims

Claims.

1. Femoro-patellar prosthesis consisting of a trochleen element with a curved semi-circular groove and a patellar element with a semi-spherical medallion of corresponding radius intended to be fixed respectively by nails and by screws to the lower femoral end and, by implantation stud, on the patella, after execution of the corresponding bone resections, characterized in that the curved semicircular groove (11) of the trochleen element (10) is integral with a sole (12), one of which of the ends comprises a fixing orifice (121) and the other end of which is extended, in the median plane, by an unfinished semi-cylindrical heel (13) provided with a transverse rod (14) disposed parallel to the sole (12 ) in the median plane thereof and oriented towards the fixing orifice (121), and in that the patellar element (30) comprises, on the bearing face of its medallion (31), circular recesses inlay (311) connected r adially by grooves (312) and, at the periphery of its implantation stud (32), inlay streaks (321) joined transversely by notches (322).

2. Devices for placing the femoro-pate II prosthesis according to claim 1, characterized in that:

1) the devices for placing the trochIean element (10) comprise: - a forceps (50) mainly consisting of a plate (51) at the base of the lacquer are fixed spacers (542 and 543) and with adjustable lateral positioning, in the plane of symmetry of the plate, a bore (512) communicates laterally, by grooves (513), with the front and rear faces of the plate (51), in which an axis (55) is mounted. ), comprising, towards one of its ends, a drilling guide hole (551), towards the other end another hole (552) provided with a removable guide rod (56), towards its middle a cutting guide (57) surmounted by a feeler arm (58) provided with a finger (581) pierced with a fixing orifice (582); The drilling guide orifice (551), the removable guide head (56) and the feeler arm (58) being located in the same plane, while the cutting guide (57) is located in a perpendicular plane,

- a milling template (60) consisting of a plate (61) provided with fixing orifices (611), soIidaire of an inclined cylindrical milling guide (62), cut longitudinally in its part located under the plate fixing (61) on the side thereof and comprising at its base a stud forming a stop (622),

- a milling cutter (70), called "tréfine", consisting of a hollow cylindrical part, partially indented, comprising, at one of its ends, cutting teeth and, at the other end, a circular heel (71 ) topped with a training tail.

2) The devices for placing the patellar element include:

- a davit (80) mainly consisting of two arms (81 and 82) connected and held parallel to each other by means of an articulated cross (83) equipped with a spring (831) permanently reminding one of the arms (82) against a thumb nut (841) mounted on a graduated threaded rod (840) secured to the other arm (81), said arms (81 and 82) being provided, at one of their ends, respectively d '' a cylindrical square threaded and graduated (821), axially drilled, on which slides a cutting guide consisting of a split bell (85) connected by a smooth ring (852), provided with a circular lip (853) to a thumb nut (86), produced in two parts, comprising a groove (861) intended to receive a lip (853) of the ring (852) of the bell (85), of a removable sliding cup (87) comprising, in its center, a pointed lug (871) and, rad ia ly, fixing orifices (872) by nails (873),

a centering template (90) consisting of a cylindrical conduit (91) comprising a circular base (92) provided with anchoring points (93),

- a drill for drilling the impIantation orifice of the pIot (32) for fixing the patellar element (30) of the prosthesis consisting of a drill bit (94) with heel (941) surmounted by a tail training (942),

- A jaw (88), adapting to the base of the bell (85), intended to facilitate the imposition by clamping the patellar element (30).

3. Devices according to claim 2, characterized in that the regulation of the spacing and of the positioning of the spoons (542 and 543) of the trochium forceps (50) is obtained by means of a dovetail groove ( 511) made at the base of the plate (51), studs (541) of the same shape located at the base of the cookers (542 and 543) and of a threaded rod (52) with two opposite threads (521 and 522) fitted with an operating knob (53).

4. Devices according to claim 2, characterized in that the end of the finger (581) of the feeler arm (58) equipping the trochlear forceps (50) is located in a plane perpendicular to the support axis (55) coincide with the upper face (571) of the cutting guide (57).

5. Devices according to claim 2, characterized in that the zero graduation of the threaded cylindrical bracket (821), supporting the cup guide bell (85), corresponds to an average resection.