NL1009831C2 - Hip prosthesis as well as an assembly of a hip prosthesis and a clamping tool. - Google Patents

Description

Title: Hip prosthesis and an assembly of a hip prosthesis and a tensioning tool

The invention relates to a hip prosthesis = provided with a first fastening assembly which is intended to be mounted in the hip bone and a second

mounting assembly intended to be J

5 mounted in the upper end of the femur, with the first and second fastening assemblies connected together by a hinged connection, with all parts of the hip prosthesis being small / and / or slender such that each can be placed in the intended Ξ The end position thereof via a bore in the femur, which bore extends from an insertion opening in the cortical bone on the lateral outer side of the femur through the femoral neck substantially in the direction of the imaginary longitudinal axis from the femoral neck to the femoral head. . r

The applicant has described such a prosthesis in the unpublished international I

patent application PCT / NL98 / 00084.

The present application aims at supplementing said international patent application with a number of possibilities for fixing the second fixing assembly in the femur bore. The subject matter of PCT / NL98 / 00084 is incorporated in the present application by reference therein (English: PCT / NL98 / 00084 is incorporated 25 herein by reference).

According to the invention, the hip prosthesis of the type described in the preamble is characterized in that the second fastening assembly is provided near a lateral end with locking means which are movable from a first position in a second position, said locking means in the first position the inlet opening. of the femur bore, these securing means in the second position being unable to pass through the inlet opening of the femur bore, in a mounted condition of "1009831; 2, the second fastening assembly, the locking means is in the second position and engages a side of a femoral interior facing the lateral cortical bone wall of the femur defining the entry opening.

5 As is known, the femur consists of, among other things, a cortical bone wall that is filled with cancellous bone. The cortical bone wall in particular is strong and can offer good resistance to the forces exerted on it. Spongy bone is not suitable for absorbing high local forces exerted thereon. Since the second fastening assembly is loaded in particular by compressive forces directed in the longitudinal direction of the second fastening assembly, it is particularly favorable when these compressive forces are absorbed by a cortical wall part. With the hip prosthesis according to the invention this intended effect is realized in that the hip prosthesis is provided with securing means which, in the second position, engage the side of the lateral cortical bone wall of the femur which borders the inlet opening 20, which faces the femoral interior. Since the locking means must have dimensions larger than the diameter of the insertion opening in the lateral cortical bone wall of the femur, the locking means are designed in such a way that they can assume two positions. In the first position, the dimensions of the locking means are still such that the locking means can still pass through the inlet opening, while in the second position such passage of the locking means through the inlet opening is no longer possible.

When the second fastening assembly 30 is introduced, the locking means in the first position are passed through the inlet opening, after which the locking means are then brought into the second position.

A large number of possibilities are available for bringing the locking means from the first position to the second position. Consider, for example, a principle known from plasterboard plugs 1009831 3 which, after being fed into a drilled hole in a plasterboard, can assume enlarged transverse dimensions by tightening.

Another possibility is to use a second securing assembly comprising a pin that can be received in the femur bore, the securing means comprising an anchor pivotally connected to a lateral end of the pin, the anchor being dimensionally longitudinally greater than the diameter of the pin, wherein the longitudinal axis of the anchor, when the anchor is in the first position, extends parallel to the longitudinal axis of the pin, the anchor in a second position being pivoted relative to of the pin, that the free ends of the anchor extend beyond the circumferential contour of the pin. After the I

inserting the pin into the femur bore, the anchor can then be pivoted from the first position to the second position. When the pen is subsequently brought under the normal loading condition that occurs when the patient is walking, the pen will be pushed in the lateral direction, with the anchor firmly against the side of the lateral cortical bone wall of the femoral interior facing the femoral interior. femur delimiting the inlet opening will lie on.

The invention also relates to a

assembly of a hip prosthesis according to the plasterboard plug principle and a clamping tool for the first I

position the securing means to the second position. :

Further elaborations of the invention are described in the subclaims and will be further elucidated hereinbelow on the basis of two exemplary embodiments, under reference to the drawing. 1

Figure 1 shows a front view of a bus which? is part of a second mounting assembly; Figure 2 shows a cross-sectional view along line II-II from Figure 1; Figure 3 shows a rear view of the front view of the bus shown in Figure 1 / Figure 4 shows a cross-sectional view along line IV-IV of Figure 3;

Figure 5 shows a cross-sectional view along line V-V

from Figure 6 of a coupling bush which forms part of the second mounting assembly; Figure 6 shows a view from the lateral end face of the coupling sleeve shown in Figure 5; Figure 7 shows a longitudinal section of the second mounting assembly, wherein the locking means are in the second position; Figure 8 shows the sleeve 4 in the femur in the first position; Figure 9 shows the sleeve 4 with the associated clamping tool, wherein the locking means are in a position situated between the first and the second position; Figure 10 shows the second fastening assembly in the fully assembled state in the femur; and Figure 11 shows a cross-sectional view of the femur containing a second exemplary embodiment of the second hip prosthesis mounting assembly.

In the figures each time only the second fastening assembly of an embodiment of the hip prosthesis according to the invention is shown. For a complete representation of a possible exemplary embodiment of a hip prosthesis, reference is made to the international patent application PCT / NL98 / 00084, the material of which is to be regarded as incorporated herein. The figures show two exemplary embodiments for securing the second securing assembly in the femur. As described extensively in PCT / NL98 / 00084, the parts of the hip prosthesis should be designed so that they can all be placed in the end position by a bore in the femur F, which bore extends from the lateral outside F0 of the femur F through the femoral neck Fn in 1009831 5 substantially in the direction of the imaginary longitudinal axis from the femoral neck to the femoral head. When placing the hip prosthesis, a relatively small incision is made in the leg that provides access to the lateral outside of the femur F. Then, a bore as described above is made in the femur F. Through this bore, a special tool, which is described in the above-mentioned international patent application,

described, the femoral head removed. Then in the E

10 hip bone the first mounting assembly to be mounted

through the bore in the femur F. After placing the first E

mounting assembly, the second mounting assembly can then be mounted.

In both exemplary embodiments, the second = 15 mounting assembly 1, 51 is provided near a lateral end with locking means 2, 2 ', 3, 3', 52 which are movable from a first position into a second position. In the first position, these locking means 2, 2 1, 3, 3 ', 52 can pass through the inlet opening Fi of the femur bore. In the second position, these locking means 2, 2 ', 3, 3', 52 cannot pass through the inlet opening Fi of the femur bore. In a z-mounted position of the second fastening assembly 1, 51, the locking means 2, 2 ', 3, 3', 52 are in the ~ second position and engage on a side C of the femoral interior I facing the ~. lateral cortical bone wall C of the femur F delimiting the entry opening Fi =. The axially directed forces exerted on the second = fastening assembly, for example E ~ when the hip prosthesis wearer is walking or standing, "30 are applied to the firm - lateral cortical bone wall C of the femur F, which bone wall ~ using the locking means. C limits the input opening, transferred. The locking means ~ 2, 2 ', 3, 3', 52 press against the inside C of the cortical bone wall and may be designed such that a relatively large pressure surface is created. 1008831 6

Such a securing of the second securing assembly 1, 51 is much stronger than if, for example, the second securing assembly 1, 51 were screwed with an end plate to the lateral outside of the cortical bone wall of the femur at the location of the insertion opening. After all, all axial forces exerted on the second fastening assembly must then be absorbed with the aid of a few screws, which have been screwed into the cortical bone wall. Such a screw connection is not stable for a long time, especially under varying loads. After all, the contact surface between the bone screws and the cortical bone wall is considerably smaller than the contact surface that can be created with the aid of locking means 2, 2 ', 3, 3', 52 which engage on a side C of the lateral interior I facing the femoral interior I cortical bone wall of the femur F.

The second mounting assembly 1 of the first exemplary embodiment is shown in the assembled state in figures 7 and 10. The second mounting assembly 1 is provided with a bush 4 and a coupling bush 8. Furthermore, the second mounting assembly 1 is provided with a pin 15 which is attached to a the medial end is provided with at least a number of hinge parts to form the hinged connection between the first mounting assembly and the second mounting assembly.

These hinge parts are not shown in figures 1-10, however, the hinge parts can for instance be formed by a ball of a ball joint, as shown in figure 11. Other possible hinge connections are described in the above-mentioned international patent application PCT / NL98 / 00048. The pin 15 is received in the sleeve 4 via a cylindrical liner 24. The sleeve 4 is provided near a lateral end with a deformation zone 2, 2 ', 3, 3' which forms the locking means. For the sake of clarity, some views of the bus 4 are shown in Figures 1-4. In these views 1008831

7 I

the locking means 2, 2 ', 3, 3' are in the first, not yet deformed position. The first position of the locking means corresponds to an as yet undeformed state of the deformation zone 2, 2 ', 3, 3'. The second position of the locking means corresponds to a deformed state of the deformation zone 2, 2 ', 3, 3'. In the not yet deformed state of the deformation zone 2, 2 ', 3, 3' the transverse dimensions of the sleeve 4 at the location of the deformation zone 2, 2 ', 3, 3' correspond substantially to the sleeve diameter DO on the other parts of the sleeve 4. In the (deformed state of the deformation zone 2, 2 ', 3, 3' (figure 7 and figure 10), the deformation zone, compared to the other parts of the sleeve, has enlarged transverse dimensions D1 in at least one direction As can be clearly seen from the figures, the sleeve 4 is provided with: a medial sleeve part 5 and a lateral sleeve part 6. The deformation zone 2, 2 ', 3, 3' connects the medial and the 1 lateral sleeve part 5, respectively. 6. In the present embodiment, the deformation zone comprises some ribs;

2, 2 ', 3, 3', each of which is provided with three I.

local weakenings 7. The weakenings 7 are [such that, when exerting a compressive force on the front ends of the medial on the one hand and the lateral sleeve part 5 on the other hand, respectively. 6, the ribs 2, 25 ', 3, 3', fold outward as shown in Figure 7. The deformation zone 2, 2 ', 3, 3' is seen as a-symmetric about the circumference of the sleeve such that the parts of the deformation zone 2, 2 ', 3, 3' radially outwardly extending in the deformed state abut against the cortical bone wall C which delimits the input opening Fi. This abutment must be realized in a 7 position, in which the bus 4 has the desired angular position at 7

relative to the femur F, i.e., a condition I.

in which the centerline of the can substantially coincides with the = 35 centerline of the femur bore in the femur F. 1 1000831 8

In order to ensure that the deformation zone 2, 2 ', 3, 3' retains its shape, even when the second fastening assembly 1 is loaded, the second fastening assembly 1 also comprises a coupling sleeve 8 which is provided with medial engaging means 9 intended for cooperation with the medial sleeve part 5. The coupling sleeve 8 is further provided with lateral engaging means 10a which are intended for co-action with the lateral sleeve part 6. In the present exemplary embodiment, the medial engaging means 9 are designed as external screw threads which co-act with internal screw threads 11 which engage in the medial bush part 5 is provided. The coupling sleeve 8 is provided at its lateral end with means 12 for engaging a tightening tool thereon. In the present exemplary embodiment, these means are formed by an internal hexagon on which an Allen key can engage.

In the present exemplary embodiment, the lateral engaging means 10 are designed as a locking bore 10a directed perpendicularly to the longitudinal axis of the coupling sleeve 8 and two locking pins 10b which can be inserted into this locking bore. The lateral sleeve part 6 is provided with a transverse bore 13, which in a deformed state of the deformation zone 2, 2 ', 3, 3' is in line with the locking bore 10a of the coupling sleeve 8. Both locking pins 10b extend through the locking bore 10a as through the transverse bore 13. The locking pins 10b therefore provide the connection of the lateral sleeve part 6 to the lateral end of the coupling sleeve 8.

As already described above, the second mounting assembly 1 is provided with a pin 15 which is connected to hinge parts of the hinged connection between the first and the second mounting assembly and with a liner 24. The pin 15 with the liner 24 is accommodated in a bore 14 in the coupling sleeve 8, which bore 14 extends from the medial end 8M in the longitudinal direction of the coupling sleeve 8.

1009831 9

A set screw bore 25 is arranged in the coupling sleeve 8, in which a set screw 16 is arranged which abuts against a free end of the pin 15 remote from the hinged connection. Using the set screw 16, the axial position of the pin 15 with respect to the coupling sleeve 8 and thus with respect to sleeve 4 and the cortical bone wall C are adjusted.

For the purpose of placing the second mounting assembly 1, the sleeve 4 is placed in the femur bore 10 until the stops 26 of the sleeve 4 abut the outwardly facing side of the lateral

cortical bone wall. The medial end of the sleeve 4 extends I.

extending into or beyond the opening at the "femoral neck Fn created by removing the femoral head from the femur F. This situation is shown in: FIG. 8. Then, using a clamping tool 17, the deformation zone 2, 2 ", 3, 3", brought into the deformed state. The clamping tool is used for this purpose

equipped with a cylindrical clamping pin or bush 22. The I

Tension pin 22 is provided at the medial end with engaging means 18 which are adapted for engaging the medial sleeve part 5. The engaging means 18 in the present embodiment are designed as external 2 screw thread 18 which is suitable for engaging the

Internal screw thread 11 in the medial sleeve part 5 of the I

bush 4. The clamping pin 22 is provided on a lateral end z with external screw thread 21 which is suitable for

co-operation with internal thread 20 of a T

pressure element 19. The pressure element 19 is provided with z 30 lever means 23 for exerting a considerable tightening torque. For the purpose of deforming the deformation zone 2, 2 ', 3, 3', the clamping pin 22 is rotated in the medial sleeve part 51 by means of the engaging means 18. The pressure element 19 is then removed with the aid of ï

3 5 of the thread 2 0 on the lateral end of the "."

clamping pin rotated until the pressure element 19 abuts against 1009831 10 the lateral end of the lateral sleeve part 6. By turning the pressure element 19 further on the clamping pin 22 with increased force, the ribs 2, 2 ', 3, 3' of the deformation zone compressed in the manner shown by the tensioning tool pulling the medial sleeve portion 5 towards the lateral sleeve portion 6. The degree of deformation can be viewed, for example, by means of X-rays. It is also possible that the clamping tool is provided with markings or the like, with the aid of which the degree of deformation can be determined. When the desired deformation of the deformation zone 2, 2 ', 3, 3' has been achieved, the locking means have assumed the second position and the clamping tool can be loosened. Figure 9 shows the sleeve 4 in a partially deformed state which occurs during the deformation of the deformation zone with the aid of the tensioning tool 17.

After the deformation as shown in Figure 7 is reached, the clamping tool 17 can be removed. In order to ensure that the sleeve 4 retains the deformed state, the coupling sleeve 8 is then fixed in the screw thread 11 of the medial sleeve part 5 by means of the screw thread 9. The coupling sleeve is rotated in the medial sleeve part 5 such that the locking bore 10a in the sleeve 8 is aligned with the transverse bore 13 in the medial sleeve part 6. Then, the two locking pins 10b can be arranged so that a connection between the lateral bus part 6 and the coupling bus 8 is created. This connection not only prevents an axial displacement of the lateral bus part 6 with respect to the coupling bush 8, but also prevents a rotation of the coupling bush 8 with respect to the medial bus part 5. It goes without saying that before placing the coupling bush 8 the pin 15 and the liner 24 must still be fitted in the sleeve 4. The axial position of the pin 15 with respect to the coupling sleeve 8 and the sleeve 4 can then be adjusted by means of the adjusting screw 16. The further fixation of the second fixing assembly 1 will result from growth of bone material around the sleeve 4. Optionally, the sleeve 4 may be coated for this purpose or the sleeve 4 may be made of porous material which allows bone ingrowth 5. The second fastening assembly 1 is shown fully assembled in the femur F in figure 10.

A second exemplary embodiment of the invention is shown in figure 11. In this exemplary embodiment, the second fastening assembly 51 is provided with a pin 53 which can be received in the femur bore. The locking means comprise an anchor 52 pivotally connected to a lateral end 53L of the pin 53. The armature 52 has a longitudinal dimension L greater than the diameter Dp of the pin 53. When the armature is in the first position, the armature extends with a longitudinal axis parallel to the longitudinal axis of the pin 53. in a second position, the anchor 52 is pivoted relative to the pin 53 such that the free ends of the anchor 52 extend beyond the circumferential contour of the pin 53. The first position of the anchor 52 is shown in broken lines in Figure 11. The second position of the anchor 52 is shown in solid lines. In order to allow the pivot of the anchor 52 to be pivoted, the armature is pivotable about a pivot axis 54 extending perpendicular to the pin 53, and a pin 55 is included in the pin 53 in which the anchor 52 is at least partly in the first position is included. When placing the second fastening assembly 51, the anchor 52 is brought into the dotted position and the pin 53 is temporarily slid slightly too far into the femur bore. Then, the anchor 52 can be pivoted into the position shown by solid lines, after which the pin 53 can be retracted somewhat laterally, so that the anchor 52 rests against the side C of the cortical bone wall facing the femoral interior I.

1009831 12

It is clear that the invention is not limited to the described exemplary embodiments, but that various modifications are possible within the scope of the invention.

j 1008331

Claims (12)

13 ί 1. Hip prosthesis provided with a first one; fastening assembly intended to be mounted in the hip bone and a second fastening assembly (1, 51) intended to be mounted in the top of the femur (F), the first and second fastening assemblies using a hinged joined together, all the parts of the hip prosthesis being small and / or slender such that they can each be placed in its arcuate end position via a bore in the femur (F), which bore extends from an inlet opening (Fi) in the I cortical bone on the lateral outer side (Fo) of the femur = (F) through the femoral neck (Fn) substantially in the direction of the imaginary longitudinal axis from the femoral neck (Fn) to the femoral head, with the second mounting assembly (1, 51) near a lateral end is provided with locking means (2, 2 ', 3, 3', 52) which are movable from a first position into a second position, these locking means (2, 2 ', = 3, 3 ', 52) in the first position the passage opening (Fi) of the ~ 20 femur bore can pass, wherein these locking means (2, 2 ', 3, 3', 52) in the second position cannot pass the inlet opening (Fi) of the femur bore, whereby in a mounted position of the second fastening assembly (1, - 51. the locking means (2, 2 ', 3, 3', 52) are in the second position and engage on a side facing a femoral interior (1) ( C) of the lateral cortical bone wall of the femur (F) defining the entry opening ^ (Fi). Hip prosthesis according to claim 1, characterized in that the securing means of the second fastening assembly T comprise a sleeve (4), which sleeve (4) is provided with a deformation zone (2, 2 ', 3, 3) near a lateral end. '), wherein the first position of the locking means I 1009831 corresponds to an as yet undeformed state of the deformation zone (2, 2', 3, 3 '), wherein the second position of the locking means corresponds to a deformed state of the deformation zone ( 2, 2 ', 3, 3'), in which the deformation zone (2, 2 ', 3, 3') is not yet deformed, the transverse dimensions of the sleeve (4) at the location of the deformation zone (2, 2 ', 3, 3') substantially correspond to sleeve diameter (Do) on the other parts of the sleeve (4), wherein in the deformed state of the deformation zone (2, 10 2 ', 3, 3'), the deformation zone has a has obtained enlarged transverse dimensions (D1) in at least one direction relative to the other parts of the sleeve (4). Hip prosthesis according to claim 2, characterized in that the sleeve (4) comprises a medial sleeve section (5) and a lateral sleeve section (6), the deformation zone comprising the medial and the lateral sleeve section (5, 6 respectively). joining together, the deformation zone comprising some ribs (2, 2 ', 3, 3') with a local weakening (7). Hip prosthesis according to claim 3, characterized in that the deformation zone (2, 2 ', 3, 3') is a-symmetrical when viewed over the circumference of the sleeve (4), such that, in the deformed state, outwardly extending parts of the deformation zone (2, 2 ', 3, 3') abut against the cortical bone wall (C) delimiting the inlet opening (Fi). Hip prosthesis according to claim 3 or 4, characterized in that the second fastening assembly (1) also comprises a coupling sleeve (8) which is provided with medial engaging means (9) intended for cooperation with the medial sleeve part (5) and provided with lateral engaging means (10a) designed to cooperate with the lateral sleeve portion (6), the engagement between the medial engagement means (9) and the medial sleeve portion (5) and the engagement between the lateral (10a) engagement means and the lateral sleeve portion (6 ) cause the 1009831 deformation zone (2, 2 ', 3, 3') to maintain its deformed position. Hip prosthesis according to claim 5, characterized in that the medial engaging means (9) are designed as an external screw thread which interacts with an internal screw thread (11) which is arranged in the medial sleeve part (5), the coupling bush (8) on its lateral end is provided with means (12) for engaging tightening tools thereon. Hip prosthesis according to claim 5 or 6, characterized in that the lateral engaging means (10) are designed as a locking bore (10a) oriented perpendicular to the longitudinal axis of the coupling sleeve and at least one locking pin which can be inserted into this locking bore. (10b), the lateral sleeve part (6) being provided with a transverse bore (13), which in a deformed state of the deformation zone (2, = 2 ', 3, 3') is in line with the locking bore (10a) of the 7 coupling sleeve (8), the one locking pin (10b) extending at least 7 through both the locking bore (10a) and the transverse bore (13). 7 Hip prosthesis according to any one of claims 5-7, characterized in that the coupling sleeve (8) has a bore (14) extending from the medial end (8M) in the longitudinal direction of the coupling sleeve (8), in which bore (14) a pin (15) of the second mounting assembly (1) can be accommodated, which pin (15) is connected to hinge parts of the hinged connection between the first and the second mounting assembly, wherein in the coupling bush (8 a 77 30 set screw (16) is provided which abuts against a free end of the 77 pin (15) remote from the hinged connection. _ 9. Assembly of a hip prosthesis according to claims 5-7 and a clamping tool (17), wherein the clamping tool [2 (17) is provided at a medial end with Z engagement means (18) which are adapted for engagement = 1009831 7 on the medial sleeve section (5), the tensioning tool (17) at the lateral end being provided with a pressure element (19) adapted to engage the front lateral end of the lateral sleeve section (6) of the sleeve (4), the tensioning tool (17) comprising means (20, 21) for reducing the distance between the pressure member (19) and the engaging means (18) at the medial end of the tensioning tool (17) against resistance. Assembly according to claim 9, characterized in that the means (20, 21) for decreasing the distance between the pressure element (19) and the engaging means (18) at the medial end of the clamping tool (17) against resistance , are constructed as internal threads (20) of the thrust member (19) and external threads (21) on the lateral end of a cylindrical tension pin or sleeve (22) which also carries the gripping means (18) on the medial end, the pressure element (19) being provided with 20 lever means (23) for exerting a considerable tightening torque thereon. Hip prosthesis according to claim 1, characterized in that the second fastening assembly (51) comprises a pin (53) which can be received in the femur bore, the locking means (52) comprising an anchor (52) pivotable with a lateral end (53L) of the pin (53) is connected, the armature (52) in a longitudinal direction having a dimension (L) greater than the diameter (Dp) of the pin (53), a longitudinal axis of the armature ( 52), when the armature (52) is in the first position, I extends parallel to a longitudinal axis of the pin (53), the armature (52) in the second position being pivoted relative to the pin ( 53) that the free ends of the armature (52) extend outside the peripheral contour 35 of the pin (53). 1008831 i Hip prosthesis according to claim 11, characterized in that the armature (52) is pivotable about a hinge axis; (54) extending perpendicular to the pin (53), the slot (53) incorporating a slot (55) in which the anchor; 5 (52) is at least partly included in the first position. 1 0 0983 1