Method for producing a tailor-made implant

Abstract

A method for producing a tailor-made implant intended to be implanted at an implantation site of a damaged bone part, the method comprising a step in which a 3D representation of a standard implant is superposed on a 3D representation of a damaged bone part by positioning said standard implant on an implantation site of the damaged bone part, in order, if necessary, to modify the dimensions and/or to adjust the shape of said standard implant, and also, if necessary, to modify the outer surface of said standard implant, which may be either the impression or substantially the impression of the outer surface of said bone part in the state prior to superpositioning of said implant, when the geometry of the damaged bone part is intended to be retained, or a functional outer surface, when said tailor-made implant is intended to be used at the interface of two bone parts cooperating with each other.

Claims

1. A method for producing a tailor-made implant intended to be implanted on a placement site of at least one damaged bone part, comprising the following steps: i. acquisition of one or more images of at least said damaged bone part; ii. graphical 3D representation of the image of at least said damaged bone part acquired at step i.; iii. superpositioning of a 3D representation of a standard implant on the 3D representation obtained at step ii., by positioning said standard implant on a placement site at the surface of said at least one damaged bone part, then, modification of the dimensions and/or adjustment of the shape of said standard implant, taking account of at least one parameter of said at least one damaged bone part, then modification of the outer surface of said standard implant, the modification of the outer surface of said standard implant being such that said standard implant thus positioned on said placement site is imparted an outer surface which is: a functional outer surface, when said tailor-made implant is intended to be used at the interface of two bone parts cooperating with each other, said functional surface being determined in such a way that, being at least partially in contact with a conjugate surface of the other bone part with which said damaged bone part cooperates, it ensures the articulation of said bone parts, the determination of said functional surface is performed while the two bone parts are in a functional position in the graphical 3D representation, an acquisition of one or more images of said two bone parts having been performed at step i; and iv. realization of the tailor-made implant from the definitive parameters of said implant obtained at step iii.

2. The production method of claim 1, wherein said superpositioning of a 3D representation of a standard implant on the 3D representation obtained at step ii. is performed by fading.

3. The production method of claim 1, wherein, before the step of determination of the outer surface of said implant, the step iii) comprises a step in which at least one local modification directly on a placement site of the graphical 3D representation of said at least one damaged bone part, determination of the shape and dimensions of said anchoring surface of an implant depending on the shape and the dimensions of said at least one local modification performed on said graphical 3D representation, said anchoring surface permitting the anchoring thereof on said damaged bone part.

4. The production method of claim 1, wherein said implant is a part of a medical device intended to be implanted.

5. The production method of claim 1, wherein said conjugate surface corresponds to the outer surface of another implant received at the surface of said other bone part cooperating with said damaged bone part.

6. The production method of claim 1, wherein the outer surface of said implant is determined by removing material from a solid surface of the graphical representation of the implant.

7. The production method of claim 6, wherein, at step iii. a), the portion of the implant to be removed is determined by subtracting the only graphical representation of said at least one bone part to be repaired obtained at step ii. from the graphical representation representing the combination of bone part and standard implant positioned on its placement site.

8. The production method of claim 1, wherein the outer surface of said implant is determined by addition of material.

9. The production method of claim 1, wherein, at step iii. b), said local modification is a continuous recess.

10. The production method of claim 1, wherein, at step iv), said implant is formed by additive manufacture.

11. The production method of claim 1, further comprising a supplementary step of additive manufacture of said at least one bone part acquired at step ii.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other advantages, aims and particular features of the present invention will become clear from the following description which is given for explanatory purposes and is non-limiting and in which reference is made to the appended drawings, in which:

(2) FIG. 1 is a perspective view of two tailor-made implants, produced by the method according to the invention, and of the tibiofemoral joint.

(3) FIG. 2 is a perspective view of two tailor-made implants produced by the method according to the invention, said implants being anchored in the tibio-femoral joint.

(4) FIG. 3 is a perspective view of two tailor-made implants produced by the method according to the invention.

(5) FIG. 4 is a perspective view of a standard implant chosen from a library. The implant is a 60% bicompartmental implant.

(6) FIG. 5 is a perspective view of a 3D representation of a bone part and the superpositioning of a 3D representation of a standard implant.

(7) FIGS. 6A AND 6B are perspective views of a 3D representation of a bone part in 3D and of a 3D representation of a standard implant and the modification of the dimensions and/or adjustment of the shape of the 3D representation of said standard implant, and the modification of the outer surface.

(8) FIG. 7 is a perspective view of a 3D representation of the tibiofemoral joint and a 3D representation of a standard implant specifically designed for the damaged bone parts.

(9) FIG. 8 is a perspective view of a 3D representation of the tibiofemoral joint and a 3D representation of an implant designed specifically for the damaged bone parts, the functional surfaces of the implant having been determined.

(10) FIG. 9 is a 3D representation of the tibiofemoral joint and a 3D representation of an implant having geometric shapes substantially corresponding to the local modifications.

(11) FIG. 10 is a 3D representation of the tibiofemoral joint and of the placement site once the shapes and dimensions and also the functional surfaces of the 3D representation of the implant are determined.

DETAILED DESCRIPTION OF THE DISCLOSURE

(12) First of all, it will be noted that the figures are not to scale.

(13) The images of the bone parts, here the bone parts cooperating in the tibiofemoral joint, have been acquired by magnetic resonance imaging and have then been segmented and modeled in 3D on a computer, said images being transmitted in STL format. A 3D image of the tibiofemoral joint, i.e. of the proximal end 30 of the tibia and the distal end 20 of the femur has thus been acquired, and, for example as shown in FIG. 1, in the functional position.

(14) On the basis of this 3D image of the tibiofemoral joint in the functional position, the recesses necessary for receiving the tailor-made implants 11, 12 have been made on the 3D image of the tibiofemoral joint in order to modify locally the proximal tibial bone end 30 and distal femoral bone end 20.

(15) A recess 21 has been formed on the distal femoral end 20 and a recess 31 has been formed on the proximal tibial end 30.

(16) By virtue of each recess 21, 31, the shape and dimensions of each implant, respectively 11 and 12, will be determined in such a way that the anchoring surface 111, 121 of each implant is the impression of the removed zone 21, 31 of the distal femoral end 20 and of the proximal tibial end 30.

(17) The tailor-made implants 11 and 12 are intended to be used at the interface of two bones parts cooperating with each other, the outer surfaces 112 and 122 of the implants 11 and 12 being functional surfaces.

(18) Thus, the functional surface 112 of the implant 11 will be determined according to the conjugate surface of the proximal tibial end 30 with which the distal femoral end 20 cooperates, this to ensure the articulation between the proximal tibial end 30 and the distal femoral end 20, the conjugate surface corresponding to the functional outer surface 122 of the implant 12.

(19) In the same way, the functional surface 122 of the implant 12 will be determined according to the conjugate surface of the distal femoral end 20 with which the proximal tibial end 30 cooperates, this to ensure the articulation between the proximal tibial end 30 and the distal femoral end 20, the conjugate surface corresponding to the functional outer surface 112 of the implant 11.

(20) The articulation between the proximal tibial end 30 and the distal femoral end 20 is advantageously recovered.

(21) Advantageously, the method for producing a tailor-made implant according to the present invention will make it possible to resect the bone only to the extent required and will preserve the bone reserves of the patient and recreate the tibiofemoral joint (FIG. 2).

(22) In the present embodiment, the distal femoral end 20 and the proximal tibial end 30 have been made by additive manufacturing in order to verify the suitability of the implants.

(23) FIG. 3 shows a tailor-made medical device composed of an implant 11 intended to be received on the distal end 20 of the femur (not shown) and an implant 12 intended to be received on the proximal end 30 of the tibia (not shown), the two implants representing a tricompartmental prosthesis obtained by the method according to the invention.

(24) Each implant comprises an anchoring surface 111, 121 being the impression or substantially the impression of at least one local modification on a damaged bone part, a functional surface 112, 122 intended to be used at the interface of the two bone parts cooperating with each other to ensure the articulation of the tibia and femur, and a protuberance 113, 123 connecting the two tabs of each body. The relationship of the outer surfaces 112 and 122 is the frictional torque.

(25) The anchoring surface of each implant comprises a surface relief intended to reinforce the anchoring of said implant. This inner relief is composed of trabeculae, which are porous structures taking up the design of the spongy bone and permitting particularly effective bone reconstruction.

(26) The implants 11 and 12 are made of titanium. The trabeculae of the anchoring surfaces 111 and 121 of the implants are made by plasma spraying of a titanium oxide suspension.

(27) Advantageously, the implants according to the invention and more particularly the total knee prosthesis according to this particular embodiment of the invention are tailor-made implants, identical to the morphology of the patient and fully integrating the personal functioning of the patient (displacement/sliding/rotation), obtained from the method according to the invention.

(28) FIG. 4 corresponds to the standard implant 40 chosen from a library. The implant is a 60% bicompartmental implant.

(29) The standard implant is modeled in CAD.

(30) FIG. 5 is a perspective view of a 3D representation of a bone part, here the proximal tibial end 30, and the superpositioning of a 3D representation of a standard implant 40.

(31) According to the method for producing a tailor-made implant according to the invention, intended to be implanted on a placement site of a damaged bone part, the images of the proximal end 30 of the tibia have been acquired by magnetic resonance imaging and have been subsequently segmented and modeled in 3D on a computer, said images being transmitted in STL format. A 3D image of the proximal tibial end 30 is thus acquired.

(32) The 3D representation of a standard implant 40 has been superposed on the 3D representation of the proximal end 30 of the tibia, by positioning said standard implant 40 on a placement site at the surface of the damaged proximal end 30 of the tibia.

(33) According to FIG. 6, the dimensions of the standard implant 40 will be modified, and the shape of said standard implant 40 will be adjusted by subtracting material from the implant.

(34) The outer surface 41 of said standard implant will be modified in such a way as to be the impression or substantially the impression of the outer surface of said bone part, occupied by said standard implant, in the state before superpositioning of said implant, so as to preserve the geometry of the bone part.

(35) Thus, and advantageously, the geometry of the proximal end will be able to be recreated.

(36) FIG. 7 is a perspective view of a 3D representation of the tibiofemoral joint and of a 3D representation of a standard implant designed specifically for the damaged bone parts.

(37) In the same way as before, the images of the proximal end 30 of the tibia and the distal end 20 of the femur have been acquired by magnetic resonance imaging and have been subsequently segmented and modeled in 3D on a computer, said images being transmitted in STL format. A 3D image of the proximal end 30 of the tibia and of the distal end 20 of the femur is thus acquired.

(38) The 3D representation of an implant 50 designed in a geometrical shape specifically intended for the damaged bone part, that is to say the lateral condyle 21 of the distal end of the femur and the lateral plateau 31 of the proximal end of the tibia, has been superposed on the 3D representation on a placement site at the surface of each damaged bone part, that is to say at the surface of the lateral condyle 21 of the distal end of the femur and at the surface of the lateral plateau of the proximal end of the tibia.

(39) In this case, the 3D representation of the implant does not correspond to a standard implant, but to a 3D representation of a newly created implant determined by the practitioner as being more adapted, from a geometrical point of view, to the damaged bone parts.

(40) The shapes and dimensions of the 3D representation of the implant will be modified in order to replace, on the 3D representation, the injured bone part at the surface of the lateral condyle of the distal end of the femur and the lateral plateau of the proximal end of the tibia by the 3D representation of the implant in order to determine the limitations of the implant and also the limitations of the anchoring of the implant in the lateral femoral condyle and in the lateral tibial plateau in such a way that the implant is the correct and personalized representation of the subtracted and damaged bone parts.

(41) The implant is intended to be used at the interface of two bones parts cooperating with each other, namely the lateral condyle 21 of the distal end of the femur and the lateral plateau 31 of the proximal end of the tibia.

(42) Moreover, once the 3D representation of the implant 50 has been positioned on the placement sites of the injured bone parts and the modifications of the dimensions and the adjustment of the shape of the implant have been carried out in order to correspond to those damaged bone parts to be treated, the outer surface of the implant anchored in the lateral condyle 21 of the distal end of the femur and the outer surface of the implant anchored on the lateral plateau of the proximal end of the tibia will be determined, the two surfaces being functional surfaces.

(43) Thus, as shown in FIG. 8, the functional surface 51 of the 3D representation of the implant anchored on the lateral plateau 31 will be determined according to the conjugate surface of the lateral condyle 21 with which it cooperates, this in order to ensure the articulation between the lateral plateau 31 and the lateral condyle 21, the conjugate surface corresponding to the functional outer surface 52 of the implant.

(44) In the same way, the functional surface 52 of the 3D representation of the implant anchored on the lateral condyle 21 will be determined according to the conjugate surface of the tibial plateau 31 with which it cooperates, this in order to ensure the articulation between the lateral plateau 31 and the lateral condyle 21, the conjugate surface corresponding to the functional outer surface 51 of the implant.

(45) The articulation between the lateral condyle 21 of the distal end of the femur and the lateral plateau 31 of the proximal end of the tibia is advantageously recovered.

(46) FIG. 9 is the 3D representation of the tibiofemoral joint and a 3D representation of an implant having geometric shapes corresponding substantially to the local modifications.

(47) In the same way as before, the images of the proximal end 30 of the tibia and of the distal femoral end 20 have been acquired by magnetic resonance imaging and have subsequently been segmented and modeled in 3D on a computer, the transmission of said images being made in STL format. A 3D image of the proximal tibial end 30 and of the distal femoral end 20 is thus acquired.

(48) The 3D representation of an ancillary 60 comprising cutting axes, each determined by the longitudinal axis of a guide tube of a tool such as a drill defining work zones, has been superposed on the 3D representation on a placement site at the surface of each damaged bone part. The cutting axes of the 3D representation of this ancillary correspond to the local modifications to be made to the surface of each damaged bone part.

(49) Thus, the 3D representation of the ancillary 60 has eight tubular elements 61, 62, 63, 64, 65, 66, 67, 68, each having a longitudinal axis, each longitudinal axis of each of the tubular elements coinciding with only one of the eight work axes determined by the practitioner on the 3D representation of the tibiofemoral joint, these work axes corresponding to the local modifications to be made to the damaged bone parts.

(50) For example, the longitudinal axis of the tubular element of the 3D representation of the ancillary will correspond substantially to the recess passing through the lower part of the lateral condyle of the distal femoral end.

(51) The longitudinal axis of the tubular element 62 of the 3D representation of the ancillary will correspond substantially to the recess passing through the lower part of the medial condyle of the distal femoral end.

(52) The longitudinal axis of the tubular element 63 of the 3D representation of the ancillary will correspond substantially to the recess directed toward the lateral cheek of the trochlea.

(53) The longitudinal axis of the tubular element 64 of the 3D representation of the ancillary will correspond substantially to the recess directed toward the juxtaposition zone between the posterior part of the lateral condyle and the lateral glenoid surface of the tibial plateau.

(54) The longitudinal axis of the tubular element 66 of the 3D representation of the ancillary will correspond substantially to the recess directed toward the juxtaposition zone between the posterior part of the medial condyle and the medial glenoid surface of the tibial plateau.

(55) The longitudinal axis of the tubular element 65 of the 3D representation of the ancillary will correspond substantially to the recess directed toward the median groove (or furrow) of the trochlea.

(56) The longitudinal axis of the tubular element 67 of the 3D representation of the ancillary will correspond substantially to the recess directed toward the medial cheek of the trochlea.

(57) The longitudinal axis of the tubular element 68 of the 3D representation of the ancillary will correspond substantially to the recess directed toward the pre-spinal surface of the upper face of the proximal end of the tibia.

(58) Thus, as shown in FIG. 10, with local modifications made to the 3D representation of the tibiofemoral joint, the shapes and dimensions of the anchoring surface of the implant will be able to be determined according to the shape and dimensions of the local modifications thus made, here the recesses 612, 622 formed on the 3D representation of the tibiofemoral joint, by subtraction of the volume of the implant 60 such that the anchoring surface of the implant permits the anchoring of the implant on the damaged bone part.

(59) Once the anchoring surface has been formed, the outer surface of the implant will be determined.

(60) The functional surface of the 3D representation of the implant anchored on the distal femoral end 20 will be determined according to the conjugate surface of the proximal tibial end 30 with which it cooperates, this in order to ensure the articulation between the distal femoral end 20 and the proximal tibial end 30, the conjugate surface corresponding to the functional outer surface of the implant.

(61) In the same way, the functional surface of the 3D representation of the implant anchored on the proximal tibial end 30 will be determined according to the conjugate surface of the distal femoral end 20 with which it cooperates, this in order to ensure the articulation between the distal femoral end 20 and the proximal tibial end 30, the conjugate surface corresponding to the functional outer surface of the implant.

(62) The articulation between the distal femoral end 20 and the proximal tibial end 30 is advantageously recovered by virtue of the knee-resurfacing prosthesis thus obtained and is intended to replace the worn rollers of the condyles which roll, slide and turn on the glenoid surfaces, themselves worn, of the tibial plateaus, and is intended to do so without in any way affecting the mechanical balance of the joint.