FR2889048A1 - Patellar retractor for implanting knee prosthesis, has terminal support point delimiting femoral intercondylar space and wing, to form frontal push surface, along mediolateral direction, of part of tendon of quadriceps with patella - Google Patents

Abstract

The retractor has an elongated body (11) with a distal end (13) having a terminal support point (15) on femoral condylar walls. The point delimits a femoral intercondylar space (3D) of a knee (1) and a wing (18) extending laterally projecting from the end to form a frontal push surface (18a), along mediolateral direction, of a part (5A) of tendon of quadriceps (5) containing a patella (2), when the points are in support in the intercondylar space.

Description

The present invention relates to a patellar spacer for use

  during surgery at the knee, especially when implanting a unicompartmental knee prosthesis. The invention relates to

  also a method of surgical intervention at the knee, using such a retractor.

  When implanting a knee prosthesis, it is necessary to incise the anterior aspect of the knee and recliner the corresponding soft parts, that is to say to release back these soft parts, so to make the operating field more visible and thus allow the surgeon access to the femoral and tibial epiphyses articulated on one another, in particular to the femoral condyles and the corresponding articular tibial cavities.

  It is known from US-A-5,380,331 to use various spacers intended to facilitate the access and treatment of bone or ligament zones of the operated knee, according to the current operating stage. This type of retractor is in the form of an elongated rigid body whose distal end is introduced at specific interstitial zones of the knee to lift, remove and / or release muscular, bony or ligamentous parts of the knee. US Pat. No. 5,380,331 thus envisages retractors for the tibia, posterior ligament, collateral ligament, etc., as well as patellar spacers whose distal end, inclined relative to the rest of the rectilinear body of the retractor, is applied against the lateral lateral surface of the tibial epiphysis, to pick the lower part of the quadriceps tendon and dislocate the patella contained in the upper part of this tendon. These patellar spacers are practically ineffective in that, by elasticity of the quadriceps tendon, the patella has a tendency to return to its original position, only a lower zone of the small tendon tendon being effectively released towards one of the lateral sides knee. The surgeon is often forced to use these patellar spreaders to force the tendon of the quadriceps and completely turn the patella, which may damage the tendon and / or the patella. In addition, as these patella spacers bear against the lateral lateral surface of the tibia, their use requires a long and deep incision of the soft parts of the knee, and even if the intervention would only aim to implant a unicompartmental prosthesis, c that is to say a prosthesis to implant only one of the outer or inner sides of the knee.

  In the field of the implantation of unicompartmental prostheses of the knee, intramedullary patellar spacers are known, whose stem-shaped distal end is to be introduced into the medullary canal of the femur, after having previously pierced an access to this canal through the femoral epiphysis. Although, in practice, this type of retractor limits the loading of the tendon of the quadriceps and the patella during the retraction of the latter, the need to access the femoral medullary canal leads to a long intervention, destructive of the bone material. of the patient and particularly invasive.

  The purpose of the present invention is to provide a patellar retractor which allows effectively recline the patella, without evers it, that is to say without returning it completely on itself, to provide a good field of view of operation at surgeon, while limiting the extent and depth of the incision necessary for its use, in particular that does not require access to the medullary canal of the femur or tibia, and which is thus particularly suitable for the implantation of a unicompartmental prosthesis.

  To this end, the subject of the invention is a patellar spacer, comprising a generally elongated body, characterized in that the distal end portion of the body is provided with at least one end support point on one of the femoral condylar walls which delimit between them the femoral intercondylar space of the knee, and a wing extending laterally projecting from this end portion to form a frontal thrust surface, in a medio-lateral direction, of the portion quadriceps tendon containing the patella when the point or points are supported in the intercondylar space.

  The quadriceps tendon contains the patella since the patella is integrated with this tendon.

  The structure of the spacer according to the invention is particularly simple to manufacture and use. When the surgeon seeks access to one of the femoral condyles, in particular to implant a unicompartmental prosthesis at this level, he inserts the distal end portion of the retractor into the femoral intercondylar space, and then, by Supporting the point or points on the wall of the treated condyle turned towards the intercondylar space, it is levered with the body of the retractor to, thanks to the lateral wing, dislocate the patella by pushing it in a directed medio-lateral direction to the other condyle. By this simple action, the surgeon effectively recovers the tendon of the quadriceps, by soliciting the latter at its current part, that is to say its part containing the patella, and thanks to the lateral wing whose surface frontal then extends along this current part of the tendon. It is understood that, in the invention, the term tip broadly means a bulge or relief, able to allow a stable support of the distal end of the spacer in the intercondylar space during his solicitation as a thrust lever of the ball joint.

  As the tendon of the quadriceps tendon is made over a substantial length of the current portion of this tendon, no overpressure or overtraining is applied to the tendon, while ensuring sufficient lateral clearance of the patella without having to turn it completely on herself. During the later stages of the surgical procedure, in particular during bone cuts of the condyle to be treated, the lateral wing of the retractor effectively maintains the patella in its retracted position, while protecting it from the ancillaries used at the treated condyle, for example ancillary cutting, since this wing is then interposed, in the mediolateral direction, between the front zone of the treated condyle and the current part of the quadriceps tendon. As the patellar retractor is conveniently handled with one hand, the surgical procedure is easy and easily reproducible.

  As the distal end of the spacer according to the invention can access the intercondylar space via the incision necessary for access to the condyle to be treated, the use of the spacer does not imply any extension of this incision, the surgical approach can then be considered as minimally invasive. In addition, no removal of bone material is required to use this spacer.

  According to other advantageous features of this spacer, taken individually or in any technically possible combination: the or each tip extends in the longitudinal extension of the distal end portion; - In longitudinal section, the or each tip, on the one hand, and the zone of the distal end portion, connected to the rest of the body, on the other hand, have respective opposite curvatures; the frontal thrust surface is concave; in a frontal view, the wing has a generally triangular outline, one of whose edges corresponds to the side of the distal end portion from which the wing extends; a second edge of the triangular contour, turned towards the point or points, has a hollow profile, advantageously corresponding to an arc of circle whose center is situated in the vicinity of the point or points; a third edge of the triangular contour, turned away from the point (s), has a curved profile directed away from the distal end portion; - The proximal end portion of the body forms or is provided with a handle for manual manipulation of the spacer; in longitudinal section, the profiles of the two end portions, except at the point or points, together form a substantially continuous arc; the distal end portion is furthermore provided with a second wing extending laterally projecting from this end portion, on the side opposite to that from which the first wing extends.

  The invention also proposes to provide a method of surgical intervention at the knee, which makes it possible to recline the patella efficiently, without turning it completely on itself, to offer a wide operational field of vision, while limiting the extent and depth of incisions or the like needed, in particular that does not require access to the medullary canal of the femur or tibia.

  For this purpose, the subject of the invention is a method of surgical intervention at the level of the knee, which comprises the following successive stages: - an anterior and external or internal zone of the knee is incised, - the edges of the incision are spread apart to at least partially discover the corresponding external or internal femoral condyle 5, - a pointed distal end of a patellar spacer is introduced into the femoral intercondylar space, via the incision, - the spacer is used as a lever for dislocate the patella by pushing the part of the tendon of the quadriceps containing the patella in a mediolateral direction directed towards the other condyle, by making said pointed end bear on the wall of the condyle discovered turned towards the intercondylar space.

  The method according to the invention leads to approaching one of the outer or inner condyles of the femur minimally invasive, since the patellar retractor used, borrowing the incision necessary for access to this condyle to treat it, n implies no extension of this incision. Thus, the method according to the invention is more particularly adapted to the implantation of a unicompartmental knee prosthesis.

  In practice, the patellar spacer as defined above is advantageously used in the method according to the invention.

  According to other advantageous features of this method: to introduce the pointed end of the spacer into the intercondylar space, this end is slid against successively the front wall and the wall facing the intercondylar space of the uncovered condyle; when the part of the tendon of the quadriceps containing the patella is pushed, the patella is slid laterally on the anterior surface of the lower epiphysis of the femur; and / or when the part of the tendon of the quadriceps containing the patella is pushed, the posterior surface of the patella directed towards the femur is maintained.

  The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the drawings, in which: FIG. 1 is a perspective view of a patellar spacer according to FIG. invention, illustrated in use at a knee shown schematically only; Figure 2 is an elevational view, taken along line II of Figure 1, of the spacer; FIG. 3 is a perspective view on a larger scale of the distal end of the spacer of FIG. 1; FIG. 4 is a diagrammatic section, along plane IV of FIG. 3, of the spacer and corresponding bony parts of the knee in the use configuration of FIG. 1; Figures 5 to 8 are perspective views illustrating successive steps of the surgical method according to the invention; and FIG. 9 is a perspective view of a variant of the patellar spacer according to the invention.

  In Figures 1 to 4 is shown a patellar retractor 10 adapted to recliner a kneecap 2 of a knee 1.

  In Figures 1 and 4, the knee 1 is shown flexed, with the lower epiphysis of the femur 3, the upper epiphysis of the tibia 4 and the tendon of the quadriceps 5 which contains, at the rear of its current portion 5A, the patella 2, while its upper 5B and lower 5C ends are respectively linked to the front faces of the femur 3 and tibia 4. The knee 1 shown being a right knee, the femoral epiphysis has an external condyle 3A and an internal condyle 3B, the upper parts of these condyles being connected by a 3C trochlea bone while, in their lower part, these condyles are distant from each other in a medio-lateral direction, delimiting between them a 3D intercondylar space, clearly visible in Figure 4. During the movements of the knee 1, the condyles 3A and 3B articulate in complementary cavities 4A and 4B provided at the upper end of the epiphysis of the tibia 4.

  The spacer 10 consists of a rigid one-piece body 11, made for example of metal or any sufficiently rigid material to allow to separate the ball 2 when using the spacer detailed further. The body 11 is in the form of an elongated piece in a curved direction X-X, the other two dimensions of this piece being significantly smaller than its length. In other words, the body 11 is in the form of a curved flat bar. The thickness of the body 11, that is to say the dimension seen in plan in Figure 2, is substantially constant over its entire length, while its width varies as detailed below.

  The body 11 has a proximal end portion 12 which forms a manual handling handle.

  In contrast, the body 11 has a distal end portion 13 connected to the portion 12 by a common portion 14 of the body, of increasing width of the portion 13 to the portion 12. Along the axis XX, the parts 12 and 14, as well as part 13 with the exception of its distal end zone 13A are each curved in the same direction and are connected to each other tangentially, so that most of the body 11 has, in longitudinal section , a continuous arched profile.

  At its distal end, the end zone 13A of the portion 13 is provided with two points 15 which extend generally in the longitudinal extension of the portion 13, the pointed end of each of these points constituting the distal end point of the Spreader 10. As shown in FIG. 3, each spike 15 has a generally pyramidal shape with a rectangular base, it being understood that other tip shapes are conceivable, for example conical shapes, and that the number of spikes can be variant, be equal to one or be greater than two.

  Each tip 15 is intended to bear firmly against the walls 3A1 and 3B1 of the condyles 3A, 3B, which delimit between them the 3D intercondylar space, as shown in Figure 4. To allow the insertion of the distal end of the spacer 10 in the intercondylar space, the thickness of the tips 15 and that of at least the end zone 13A are smaller than the medio-lateral dimension of this space, while the width of the terminal zone 13A is less to the vertical dimension of the intercondylar space considered with the knee flexed.

  The tips 15 are connected to the portion 13 in a curved manner. As can be seen in FIG. 2, the tips and the end zone 13A do not, however, extend in a direction connecting to the direction XX without any change in curvature, but, on the contrary, in longitudinal section of the spacer, the tips 15 and the end zone 13A, on the one hand, and the remainder 13B of the part 13, that is to say the zone of the part 13 facing the parts 12 and 14, on the other hand, have respective curvatures opposed. Thus, on a frontal side of the body 11 seen in the viewing direction of FIG. 2, the portion 13 has a concave face at its zone 13A and then convex at its zone 13B, while at the other side, it has a convex front face at its area 13A and concave at its area 19B.

  The zone 13B of the portion 13 is provided with a solid wing 18 rigidly connected to the rest of the body 11, for example being integral with this body. This wing extends laterally projecting from the zone 13B, from the longitudinal edge 13C of this zone turned upwards in use. The wing 18 has a substantially constant thickness, equal to that of the body 11, and, along the X-X axis, a curvature identical to that of the zone 13B, as can be seen in FIG.

  In this way, at the two frontal sides of the wing 18 seen in the direction of observation of Figure 2, this wing household respectively a concave surface 18A and a convex surface 18B convex. In practice, the curvature of the concave face 18A is sized to correspond substantially to the geometry of the lateral flanks of the current portion 5A of the tendon of the quadriceps 5.

  Viewed frontally, the wing 18 has a generally triangular shape, one of the edges, indicated in dashed lines in FIG. 3 and referenced 18C, corresponds to the longitudinal edge 13C of the portion 13. A second edge 18D of this triangular shape, turned towards the tips 15, has a hollow profile, approximately corresponding to a circular arc C centered at a point 0 located in the vicinity of the points 15, while the third edge 18E has a curved profile.

  The use of the spacer 10 will be described below, essentially with reference to FIGS. 5 to 8.

  In FIG. 5, it is considered that the knee represented corresponds to the knee 1 of FIG. 1, being noted that, contrary to FIGS. 1 and 7, on which all of the soft parts of the knee, except the quadriceps tendon 5, do not are not shown for reasons of visibility, the outer skin envelope and all surrounding soft tissues of the knee are shown in Figure 5, as well as Figures 6 and 8.

  The surgical procedure described below aims to implant a unicompartmental knee prosthesis at the outer compartment of the right knee 1. For this purpose, as shown in Figure 5, the surgeon places the knee flexion configuration and then incise by the front soft parts of the right compartment of the knee. The edges of the incision 20, made substantially vertically, are separated by surgical claws 22.

  The incision and the separation of the soft parts of the right compartment of the knee 1 are continued until the external condyl 3A of the femur 3 is accessible to the surgeon by a voice initially globally anteroposterior, as represented in FIG.

  Without further incising the soft tissues of the knee, the surgeon manipulates the patellar retractor 10, grasping it at its proximal end portion 12. To do this, the surgeon introduces the end zone 13A of the portion 13 of the spacer in the knee 1, by sliding the concave face of its pointed end zone 13A against the front wall of the external condyle 3A, in the direction of the intercondylar space 3D. The concavity of this pointed end zone facilitates the positioning and the progression of the spacer along the external condyle 3A, first on its front face and then on its intercondylar face 3A1r the body 11 of the spacer is thus manipulated so that the wing 18 extends away from the outer flank of the tendon of the quadriceps 5, as shown in dotted lines in Figure 7. In this configuration, the concave front face 18A is turned towards the outer side of the current portion 5A of the tendon quadriceps 5 also shown in dotted lines, while the opposite convex face 18B is turned to the outer condyle 3A.

  The distal end of the portion 13 is thus introduced until its tips 15 are received in the 3D intercondylar space. Advantageously, the length LD of the distal end of the portion 13, between the tips 15 and the junction between the edges 18C and 18D of the wing 18, is provided to guarantee the surgeon that the tips 15 have reached a sufficient depth in the intercondylar space when the edge 18D of the wing 18 is in the immediate vicinity, or substantially in contact with the soft parts adjacent to the condyle 3A.

  Then, as indicated by the arrow 24 in FIG. 7, the surgeon drives the spacer 10, still by manipulating it at the proximal end portion 12, in a tilting motion in a generally horizontal plane, centered on the 3D intercondylar space. More specifically, during the tilting drive of the spacer 10, the tips 15 bear against the wall 3A1 of the outer condyle 3, as shown in Figure 4, which forms stable and resistant points of support. The concave face 18A of the wing is then brought into contact against the outer flank of the running portion 5A of the tendon of the quadriceps 5, then pushes laterally inwardly this portion 5A, to bring the tendon in its shifted position shown 7. The spacer is thus used in the manner of a tilting lever of the tendon 5. By complementarity of the forms between the face 18A and the outer flank of the tendon 5, the training force of this tendon is distributed over substantially the entire length of the running part 5A, in other words over the length of the tendon at which the ball 2 is located, without the wing 18 coming into pressing contact with the femoral epiphysis since its edge 18D is arched centrally on the intercondylar space. The patella is thus reclined.

  Since the tilting is generally centered on the 3D intercondylar space, the patella 2 slides on the anterior face of the femoral epiphysis 3, passing from its sagittal position in dotted lines to FIG. 7, in which it is received in the femoral trochlea 3C, at an inwardly displaced position, but without being completely turned over since the posterior surface of the patella remains directed towards the femur.

  In its reclined configuration, the patella 2 and the corresponding portion 5A of the tendon 5 release anteroposterior access to the entire external condyle 3A, as shown in FIG. 8. This condyle 3A is then completely exposed to the surgeon who, at the Using appropriate ancillaries, such as a saw 26 or the like, performs one or more surgical actions necessary for the implantation of the unicompartmental prosthesis at this condyle. During these actions, the wing 18 protects the ball 2, in particular thanks to its curved edge 18E.

  Thus, the patellar retractor 10 is an easy to handle ancillary and particularly effective for reclining the current portion 5A of the quadriceps tendon, without applying excessive excessive stresses to the latter.

  This spacer is easy to manufacture, for example from a substantially flat piece and machined to present the tips 15 and the wing 18, which is subsequently bent to give the retractor its final curvatures.

  It is understood that the patellar spacer 10 described above is specifically intended to recline the patella during an intervention at the external condyle of a knee. If it is desired to intervene at the level of the internal condyle, for example of the condyle 3B for the knee 1, another patellar spacer should be used, having arrangements similar to the spacer 10 and obtained by symmetry of the spacer 10 relative to at the plane P indicated in FIG. 2, which, for the retractor 10 in use, corresponds to a sagittal plane of the knee.

  In Figure 9 is shown a variant of the patellar retractor 10, which differs from that of the preceding figures only by the additional presence of a second lateral flange 30 located on the longitudinal side opposite to that of which extends l wing 18. The wing 30 thus extends projecting from the body 11 from the lower longitudinal edge 13D of the portion 13. This additional wing 30 has arrangements similar to those of the wing 18, especially with respect to its curvature, so that the wing 30 allows, when driving the retractor in the manner of a lever described above, to push, in a mediolateral direction, the lower end 5C of the tendon Quadriceps 5

  Various adaptations and variants patellar spacers, as well as the surgical method described above are also possible. For example, the proximal end portion 12 of the spacer can be equipped with an attached handle, including a recessed profile and bumps to facilitate manual gripping by the surgeon.

Claims (10)

  Patellar retractor (10) having a generally elongated body (11), characterized in that the distal end portion (13) of the body (11) is provided with at least one end point (15). bearing on one of the femoral condylar walls (3A1, 3B1) which delimit between them the intercondylar femoral (3D) space of the knee (1), and a wing (18) extending laterally projecting from this part of end (13) to form a front surface (18A) of thrust, in a mediolateral direction, of the portion (5A) of the quadriceps tendon (5) containing the patella (2) when the at least one point bears in the intercondylar space.   2. Retractor according to claim 1, characterized in that the or each tip (15) extends in the longitudinal extension of the distal end portion (13).   3. Retractor according to one of claims 1 or 2,   characterized in that, in longitudinal section, the or each tip (15), on the one hand, and the area (13B) of the distal end portion (13), connected to the remainder (12, 14) of the body ( 11), on the other hand, have respective opposite curvatures.   4. Spreader according to any one of the preceding claims, characterized in that the front thrust surface (18A) is concave.   5. Spreader according to any one of the preceding claims, characterized in that, in front view, the flange (18) has a generally triangular outline, one of the edges (18C) corresponds to the side (13C) of the part of distal end (_1.3) from which the wing extends.   6. Spreader according to claim 5, characterized in that a second edge (18D) of the triangular contour, facing the point or points (15), has a hollow profile, preferably corresponding to an arc (C) of which the center (0) is situated in the vicinity of the point (s) (15).   7. Spreader according to one of claims 5 or 6, characterized in that a third edge (18E) of the triangular contour, turned away from the point or points (15), has a curved profile directed to the opposite of the distal end portion (1.3A).   8. Retractor according to any one of the preceding claims, characterized in that the proximal end portion (12) of the body (11) forms or is provided with a handle for manual manipulation of the spacer (10).   9. Spreader according to claim 8, characterized in that, in longitudinal section, the profiles of the two end portions (12, 13), except at the point or points (15), together form a substantially continuous arc.   10. Spreader according to any one of the preceding claims, characterized in that the distal end portion (13) is further provided with a second flange (30) extending laterally projecting from said end portion ( 13), on the side opposite to that from which extends the first wing (18).