FR2879916A1 - Hip prosthesis for human being, has spacer to integrate eyelet with acetabulum, and fixation screw cooperating with eyelet`s opening and having stem, threading for step and another threading formed between shoulder head and determined point - Google Patents

Abstract

The prosthesis has an insert (5), a prosthesis leg (7), a connection spacer (13) to integrate an eyelet (10) with an acetabulum (1), and a fixation screw (15) to cooperate with the eyelet`s opening (11) having a tapping for a step. The screw has a cylindrical stem, a shoulder head (19), a threading (23) for the step, and a threading (28) that is formed on the stem between the head (19) and a determined point.

Description

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HIP PROSTHESIS

  The present invention relates to hip prostheses comprising an acetabulum whose outer face of substantially spherical shape is determined to be impacted in a complementary cavity made in the acetabulum of the pelvis, at least one insert adapted to be mounted in the acetabulum in cooperation with the inner face of said acetabulum, and a prosthesis lug of which a distal end is adapted to be implanted in the medullary canal of a femur and therefore the other proximal end comprises a head of generally spherical shape adapted to cooperate in rotation in a spherical complementary housing made in the insert, which finds a particularly advantageous application as double rotation prostheses such as those described in EP-1 099 426, EP-0 360 734, FR-2 387 641 and FR: -2,744,357.

  The problem that arises with this type of prosthesis is that of placing the acetabulum in the acetabulum of the pelvic bone and of maintaining it in time.

  Also, the present invention is intended to provide a hip prosthesis which facilitates its implementation and which also helps to promote the holding in time of the acetabulum that includes this kind of hip prosthesis.

  More specifically, the subject of the present invention is a hip prosthesis comprising: an acetabulum whose outer face of substantially hemispherical shape is determined to be impacted in a complementary cavity made in the acetabulum of the pelvis, and at least one insert capable of to be mounted in said acetabulum in cooperation with the internal face of said acetabulum, and É a prosthesis lug whose distal end is adapted to be implanted in the medullary canal of a femur and whose other proximal end has a shaped head spherical general adapted to cooperate in rotation in a substantially hemispherical complementary housing made in said insert, characterized in that it further comprises: E at least one eyelet, said eyelet having a through-hole whose wall comprises a tapping of a step of value P, r é a binding spacer for securing said eyelet with a portion of the bo rd of said acetabulum, and E a fastening screw capable of cooperating with the penetration through said eyelet, said screw comprising: a substantially cylindrical rod having a longitudinal axis, a shoulder head integral with a first end of the rod, a first thread with a pitch of value P, whose diameter at the thread vertex is at most equal to the diameter at the thread vertex of the thread, said first thread being formed on the rod between a given point and the second end of said thread; rod, and * a second thread of a pitch P value and complementary tapping, said second thread being formed on the rod between the shoulder head and said determined point.

  Other characteristics and advantages of the invention will become apparent from the following description given with reference to the accompanying drawings, which are illustrative but in no way limiting, in which: FIGS. 1 to 5 show an embodiment of a hip prosthesis according to the invention, the figures, 1, 2 3 and 5 being perspective representations of the various components of the prosthesis, Figure 4 being a partially cutaway view of the prosthesis with the acetabulum implanted in an acetabular cavity of the bone basin, of a human person.

  It is first of all specified that, in the figures, the same references designate the same elements, whatever the figure on which they appear and whatever the form of representation of these elements. Similarly, if elements are not specifically referenced in one of the figures, their references can be easily found by referring to another figure.

  It is also stated that the figures essentially represent a single embodiment of the object according to the invention, but that there may be other embodiments that meet the definition of this invention.

  It is furthermore specified that, when, according to the definition of the invention, the object of the invention comprises "at least one" element having a given function, the embodiment described may comprise several of these elements. Conversely, if the embodiments of the object according to the invention as illustrated comprise several elements of identical function and if, in the description, it is not specified that the object according to this invention must obligatorily comprise a number particular of these elements, the object of the invention may be defined as comprising "at least one" of these elements.

  Finally, it is pointed out that when, in the present description, an expression defines alone, without specific specific mention concerning it, a set of structural characteristics, [for example E = E (p, t, s, ...)] , these characteristics can be taken, for the definition of the object of the protection requested, when technically possible, either separately, [for example s, and / or i, and / or p,

  .], either in total and / or partial combination, [eg E (sp), and / or E (s, t), and / or E (ti, p), and / or E (s, p)] The invention relates to a hip prosthesis, which as illustrated in the five figures, comprises in a final configuration, an acetabulum 1 whose outer face 2 of substantially hemispherical shape is determined to be impacted in a complementary cavity 3 performed in the acetabular bone of the pelvis 4, at least one insert 5 adapted to be mounted in said acetabulum 1 in cooperation with the internal face 6 of said acetabulum, and a prosthesis lug 7, a distal end of which is adapted to be implanted in the acetabulum. medullary canal of a femur and whose other proximal end comprises a generally spherical shaped head capable of cooperating in rotation in a substantially hemispherical complementary housing formed in said insert 5.

  It is clearly stated that the invention applies equally well to a prosthesis comprising a single insert and several, in general, two which are pivotally mounted one inside the other, to obtain what technicians call "double ball joint". rotation".

  The prosthesis further comprises at least one eyelet 10, said eyelet having a through-hole 11, the wall of which has a tapping 12 of a pitch P, a connecting strut 13 for securing the eyelet 10 with a part of the edge 14 said acetabulum 1, and a fixing screw 15 adapted to cooperate with the piercing 11 passing through the eyelet 10.

  According to a particularly advantageous characteristic according to the invention, this screw 15 comprises a substantially cylindrical rod 16 advantageously of revolution, thereby having a longitudinal axis 17, a shoulder head 19 integral with a first end 21 of the rod 16, a first thread 23 with a pitch P, the diameter of which at the thread vertex is at most equal to the diameter at the thread vertex of the thread 12, this first thread 23 being formed on the rod 16 between a given point 25 and the second end 27 of the rod, and a second thread 28 with a pitch P and complementary to the thread 12, this second thread being formed on the rod 16 between the shoulder head 19 and this determined point 25.

  Preferably, the length of the second thread 28, taken along the axis 17 of the rod 16, is at least equal to the thickness of the eyelet 10 taken along the axis 30 of the through-hole 11, and advantageously the first and second threads 23, 28 are in continuity with one another.

  In addition, it is advantageous for the first thread 23 to be a self-tapping thread of the bone type and the second thread 28 to be a mechanical type thread.

  Preferably, the prosthesis further comprises an impaction head 40 whose outer shape is substantially complementary to the inner face 6 of the acetabulum 1, a gripping sleeve 42 of the impaction head 40, and holding means 44. of this handle 42 with respect to the acetabulum 1 so that the impaction head 40 can be kept in contact with the inner face 6 of the acetabulum 1.

  In a particularly advantageous embodiment, more particularly illustrated in FIG. 5, the holding means 44 of the handle 42 with respect to the acetabulum so that the impaction head can be held in contact with the internal face of the acetabulum, comprise a crosspiece 46, an orifice 48 formed in a first end 50 of said crosspiece 46, a bolt 52 or the like shoulder head 54 and rod 56 having a thread complementary to the thread 12 formed in the wall of the piercing 11 through the eyelet 10, for securing the crossmember 46 with the acetabulum 1 when the rod of the bolt 56 passes through the orifice 48 and is screwed into the bore 11 of the eyelet 10.

  The crosspiece 46 is further arranged so that, when its first end 50 is secured to the eyelet by means of the bolt, its second end 58 comes to rest on the portion 60 of the edge 14 of the acetabulum substantially diametrically opposed to that 62 which is secured to said spacer 13.

  The prosthesis further comprises means 62 for linking the handle 42 with the crosspiece 46 so that the impaction head 40 can be held in contact with the inner face 6 of the acetabulum 1.

  In addition it is preferred that the handle 42 is substantially cylindrical, at least over a certain length, and in this case the means 62 for connecting the handle 42 with the crosspiece 46 so that the impaction head 40 can being held in contact with the inner face of the acetabulum, comprise a hole 64 or the like substantially oriented on the diameter of the inner face 6 of the acetabulum passing through its polar apex and whose section is substantially complementary to the cross section of the handle 42 so that the handle can slide and pivot in this hole 64.

  In addition, it is also preferable for the prosthesis to comprise a strip 70 of pins 72 or the like on the external face 2 of the acetabulum 1, this band 70 being defined between two parallel planes 74, 76 substantially perpendicular to the diameter of the external face 2 of the cotyle passing through its polar summit 66.

  The acetabulum, as described above, is implanted as follows: Firstly, the practitioner gives the prosthesis the structure as described above and illustrated in Figure 5. After preparing the cavity acetabulum, by means of the grip handle 42 with which it applies a penetration force to the acetabulum, it impacts it in this cavity, to anchor at least temporarily the acetabulum with the pins 72 of the band 70, to give it a position as that which is illustrated in FIG. 5, the eyelet pressed against the pelvic bone 4.

  Once the acetabulum is impacted, it unscrews the bolt 52 and removes the crosspiece 46 and the impaction head with its handle 42, which is released at the piercing 11 of the eyelet 10.

  After these first manipulations, it then screws the screw 15 into the pelvic bone passing through the piercing 11. The portion of the rod 16 which has the first thread 23 enters the acetabulum by self-tapping. When all the thread 23 has penetrated into this bone, the second thread 28 which has the same pitch as the first and which is in continuity with the first, continues to be screwed into the tapping 12 of the piercing of the loop 10, with the same penetration as in the bone since the two P steps are the same.

  Once the shoulder head comes into abutment against the eyelet, the screw 15 can no longer penetrate into the bone, the head abutting against the second threading prohibiting any additional screwing and thus prevents, in case of additional screwing, with a only eyelet 10, a tilt that could exert on the acetabulum around the fulcrum that would constitute in this case the eyelet 10. It is varied that this disadvantage could be offset by the presence for example of them eyelet diametrically opposite on the acetabulum , but this realization is almost not possible because of the lack of bone for screws such as screw 15 and it is still preferable to limit the number of these implantation of screws in the bones Once this implantation is completed, the or the inserts are placed in the acetabulum as in the case of the prior art, and the spherical head of the prosthesis lug 7 once implanted in the medullary canal is positioned in the housing of the serves.

  The advantages of the prosthesis according to the invention appear in the description made above, without any need to further develop them.

Claims (1)

7 CLAIMS   1. Hip prosthesis comprising: E an acetabulum (1) whose outer face (2) of substantially hemispherical shape is determined to be impacted in a complementary cavity (3) made in the acetabulum of the pelvis (4), at least one insert (5) adapted to be mounted in said acetabulum (1) in cooperation with the inner face (6) of said acetabulum, and E a prosthesis lug (7), a distal end of which is adapted to be implanted in the canal medullary of a femur and whose other proximal end comprises a generally spherical head adapted to cooperate in rotation in a substantially hemispherical complementary housing formed in said insert (5), characterized in that it further comprises: E at least one eyelet (10), said eyelet having a through-hole (11) whose wall comprises a tapping (12) of a pitch P, É a connecting spacer (13) for securing said eyelet (10) with some of the edge (14) of said cup (1), and E a fixing screw (15) adapted to cooperate with the piercing (11) passing through said eyelet (10), said screw comprising: * a substantially cylindrical rod (16) having a longitudinal axis (17), * a shoulder head (19) integral with a first end (21) of the rod (16), * a first thread (23) of a pitch of value P, whose diameter at top of thread is at most equal to the diameter at the thread vertex of the thread (12), said first thread (23) being formed on the rod (16) between a given point (25) and the second end (27) of said rod , and * a second thread (28) of a pitch P value and complementary to the tapping (12), said second thread being formed on the rod (16) between the shoulder head (19) and said determined point ( 25).   2. Prosthesis according to claim 1, characterized in that the length of the second thread (28), taken along the axis (17) of the rod (16), is at 2879916 8 less equal to the thickness of the loop (10) taken along the axis (30) of the through-hole (II).   3. Prosthesis according to one of claims 1 and 2, characterized in that the first and second threads (23, 28) are in continuity with one another.   4. Prosthesis according to one of claims 1 to 3, characterized in that the first thread (23) is a self-tapping thread type bone and the second thread (28) is a thread type mechanical.   5. Prosthesis according to one of claims 1 to 4 adapted to be impacted by means of an ancillary having an impaction head (40) whose outer shape is substantially complementary to the inner face (6) of the acetabulum (1). and a gripping sleeve (42) of said impaction head (40), characterized in that it comprises means (44) able to hold (44) the handle (42) relative to the acetabulum (1). ) so that said impingement head (40) is adapted to be maintained in contact with the inner face (6) of the acetabulum (1).   6. Prosthesis according to claim 5, characterized in that the means (44) adapted to maintain the handle (42) relative to the acetabulum so that the impaction head is able to be maintained in contact with the face internal portion of the acetabulum comprises: E a crosspiece (46), É an orifice (48) formed in a first end (50) of said crossmember (46), É a bolt (52) with a shoulder head (54) and rod (56) having a thread complementary to the thread (12) formed in the wall of the bore (11) passing through the eyelet (10), for securing said crossmember (46) with said cup (1) when the bolt rod ( 56) passes through said orifice (48) and is screwed into the piercing (11) of the eyelet (10), said crosspiece (46) being further arranged so that when its first end (50) is secured to said eyelet by means of said bolt, its second end (58) comes to rest on the part (60) of the edge (14) of the acetabulum. diametrically opposed to that (62) which is secured to said spacer (13), and 2879916 9E means (62) for connecting said handle (42) with said crossbar (46) so that the impaction head (40) can be maintained in contact with the inner face (6) of the acetabulum (1).   7. Prosthesis according to claim 6, when the handle (42) is substantially cylindrical, characterized in that the means (62) for connecting said handle (42) with the crosspiece (46) so that the head impaction (40) can be maintained in contact with the inner face of the acetabulum, comprise a hole (64) substantially oriented on the diameter of the inner face (6) of the acetabulum passing through its polar apex and whose section is substantially complementary of the cross section of the handle (42) so that said grip handle is slidable and pivotable in the hole (64).   8. hip prosthesis according to one of the preceding claims, characterized in that it comprises a strip (70) of pins (72) on the outer face (2) of said acetabulum (1), this band (70) being defined between two parallel planes (74, 76) substantially perpendicular to the diameter of the outer face (2) of the acetabulum passing through its polar apex (66).