WO2000015154A1

WO2000015154A1 - Implantable prosthesis having at least two sections which can be displaced in relation to one another, and the use of displaceable sections

Info

Publication number: WO2000015154A1
Application number: PCT/EP1999/006689
Authority: WO
Inventors: Philipp Kropf
Original assignee: Argomedical Ag
Priority date: 1998-09-11
Filing date: 1999-09-10
Publication date: 2000-03-23
Also published as: DE19841611B4; DE19841612A1; DE19841611A1

Abstract

The invention relates to an implantable prosthesis (10) having at least two sections (12, 34, 40) which can be displaced in relation to one another. The invention especially relates to a prosthesis for the upper end of a human upper arm comprising a shaft (12) which can be inserted into the humerus channel thereof, and having a dome-shaped joint head (40) assigned to the joint socket located adjacent to the upper arm. Said joint head is connected to a face (14) of the shaft (12) in an eccentric position relative to the center axis (M) thereof by means of an intermediate disc (34) which has a circular periphery (34a) and which comprises socket pins (32, 32a) or a similar peg-like element that is formed on. Said socket pin or similar peg-like element can be inserted into a borehole (16, 46) in both the joint head and in the shaft (12). According to the invention, the sections (12, 34, 40) which can be displaced in relation to one another can be continuously displaced in relation to one another around axes (M, M1; Q, Q1), said displacement occurring in at least one displacement plane (E, E1). In addition, at least one of the socket pins (32, 32a) is eccentrically arranged at a radial distance (9) from the axis (Q) of the intermediate disc (34) and the intermediate disc (34) is inserted with a centric socket pin (32a) into a recess (44, 46) which corresponds to the shaping thereof and which is eccentrically shaped inside a connecting surface (42) of the joint head (40).

Description

DESCRIPTION

Implantable prosthesis with at least two cross-adjustable sections and use of adjustable sections

The invention relates to an implantable prosthesis with at least two mutually adjustable sections, in particular a prosthesis for the upper end of a human upper arm with a shaft which can be inserted into its humeral canal and a dome-shaped joint head which can be assigned to the joint socket adjacent to the upper arm and which is connected to it by means of - both to it as well as to the shaft one insertable plug or the like into a hole. having a peg-like shape - washer of circular circumference to an end face of the shaft in an eccentric position - to the central axis thereof - can be connected. The invention also covers the use of adjustable sections and an intermediate washer on an adjustment plane.

Such a joint prosthesis can be found in EP 0 549 480 AI. A central spigot protrudes from the washer on both sides. An eccentric bore is provided in the joint head for the plug on the head side and a ring of smaller bores around this for receiving an axially parallel fixing pin which engages both in this and in the intermediate disk. The adjustment of the joint or humeral head takes place gradually, so it cannot be adapted to the circumstances in all situations. In addition, the construction of this shoulder joint prosthesis does not allow the cutting axes or resection axes to be displaced.

EP 0 712 617 AI also describes a joint prosthesis in the shaft of which the joint head is supported by means of a ball joint. This also does not offer fine tuning of the joint head. Knowing this state of the art, the inventor has set himself the goal of designing a prosthesis of the type mentioned at the outset in such a way that when it is adapted to the particular anatomical conditions of the human bones to be connected to it, fine stone adjustment is also possible without problems.

The teaching of the independent claim leads to the solution of this task; the subclaims indicate favorable further training. In addition, all combinations of at least two of the features disclosed in the description, the drawing and / or the claims fall within the scope of the invention.

According to the invention, the mutually adjustable sections are arranged to be infinitely adjustable relative to each other about axes on at least one adjustment plane, preferably one of the socket pins should be arranged at a radial distance from the axis of the intermediate disk.

Thanks to these specifications, the shaft and joint head - or two parts of other implant prostheses that can be adjusted accordingly - can be continuously shifted against each other on that face or parallel to it.

According to another feature of the invention, the washer - which can be inserted into a recess of one of the adjacent sections which has the same shape - is to be inserted with a central plug pin into a corresponding recess which is eccentrically formed in a connecting plane of the joint head; the other - eccentrically attached - plug pin is assigned to the end face of the shaft. That connection level also determines one of two adjustment levels of the prosthesis; the other lies in the face of the shaft. It has proven to be advantageous to have the diameter of the intermediate disk correspond approximately to half the diameter of the joint head and its height approximately to the respective height of its plug pins; For this purpose, the height of the intermediate washer should be approximately one third of its diameter with a preferred bolt diameter, the length of which corresponds to the diameter of its intermediate washer, such as approximately 1: 2.5 to 1: 3.0. In addition, the radial distance of the eccentrically provided plug pin from the axis of the washer should correspond to approximately half the pin diameter.

It is clear that the connection surface of the joint head according to the invention offers a flat sack recess displaced from its axis for inserting the intermediate washer, which is equipped with a plug pin on both sides of the washer. The two plug pins are radially offset from each other and allow the joint head to be moved continuously with respect to the prosthesis.

The plug pins are preferably press-fitted into their blind holes. For example, you can offer an annular press-fit area, the height of which is sufficiently dimensioned with a tenth of the bolt height, but can also be wider.

In a further embodiment, the socket pin may be slightly conical; this taper of the plug pin also ensures its seat in the cylindrical blind bore.

According to a further feature of the invention, the position of the intermediate disk is fixed by plugging it together with the joint head or the shaft. In a specific embodiment of the invention, the diameter of the plug pins can measure 1 to 9 mm, preferably up to 7 mm. For this purpose, the intermediate or eccentric disc then has a diameter of 10 to 35 mm - preferably 12 to 30 mm - and a thickness of 2 to 8 mm, preferably 3 to 7 mm.

With such dimensions, it has proven to be advantageous if the flat recess for the washer in the spherical joint head of the implantable prosthesis is displaced from its central axis by up to 10 mm, preferably up to 8 mm.

The assignment according to the invention of two adjustable sections and their intermediate disc on an adjustment plane can also be used for implantable prostheses of a different type.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in

1: a schematic side view of a modular shoulder joint prosthesis with an intermediate disk assigned to a shaft and a joint head that can be placed on this, in a separated state;

2: the shaft of FIG. 1, which has an end face on one end;

3: the top view of the end face of the shaft;

4 shows a cross section through FIG. 2 along the line IV-IV;

5: the partially sectioned front view of the shaft;

6 is a side view of the washer;

7, 8: top views of the intermediate washer;

9: an enlarged detail from

6 according to their arrow IX;

10: the top view of the joint head;

11 is a sectional side view of the

Condyle; Fig. 12: an enlarged compared to Fig. 10

Representation of another joint head;

13: a front view of the shoulder joint prosthesis in a first setting;

14 to 17: the shoulder joint prosthesis of FIG. 13 in different - mutually different - settings of its joint head.

A prosthesis 10 for a human shoulder joint, not shown, has a shaft 12 with an end face 14, the central axis M of which is inclined at an angle w of 45 ° relative to the longitudinal axis A of the shaft 12. The greatest length a of this shaft 12 measures 125 mm, the width b of the end face 14 is approximately 14 mm and its length e is approximately 23 mm. The projection length e _1, which can be seen in FIG. 2, of the end face 14 into a plane crossing the longitudinal axis A at a right angle is then 27.3 mm.

The central axis M of the end face 14 determines the position of a blind hole 16 of diameter d of approximately 7 mm with a conical end 17 there. The head region 22 is opposite the free shaft end 20 of width 11 of a width of 11 mm, which ends on an inclined foot surface 18 of the shaft 14 extended to that length e or e _x . The upper, slightly rounded narrow edge 15 of the end face 14 is offset by a dimension h of about 4.5 mm from the alignment of its shaft side 24 thanks to an inclination region 24 _a provided in the latter of the axially parallel length a of about 25 mm; the other shaft side 26 is curved outwards toward the second narrow edge 15 _{a of} the end face 14 in a radius r = 70 mm. In the roughly constant cross-sectional area of the shaft run on both sides of central flat grooves 28 of width f _x from here 4.6 mm and length i of 65 mm.

At a distance k of approximately 5.5 mm, that head region 22 of the shaft 12 crosses a transverse bore 30 near the shaft side 26 curved in the radius r; at 30 _a , a possible further transverse bore near the upper narrow edge 15 of the end face 14 is also indicated in FIG. 2 at a distance from the blind hole 16. 31 denotes a tangential bore to the blind hole 16 for a screw fixing the bolt seat.

The blind hole 16 of the end face 14 serves to receive a plug pin or plug pin 32 - corresponding to the round cross section of the diameter c _x of 7 mm - an intermediate or eccentric disc 34 of the diameter d of 20 mm and the height n of 5 mm, on both sides is provided with such a plug pin 32, 32 _{a of the} same height n; the shank pin 32 is radially offset at an axial distance q of 3 mm to the central axis Q of the eccentric disk 34, the second pin 32 _a projects axially from the disk surface 35. Depending on the version, the distance q can measure from 1 mm to 10 mm - preferably up to 8 mm.

FIG. 8 illustrates a scale 36 oriented to the disk center Z with marking lines on the disk surface 35 _a , FIG. 9 shows the eccentric plug pin 32 with an annular press-fit area 38 of width s of 0.5 mm, which is at a distance n _x of 1.5 mm from the other disk surface 35 _{a of} the eccentric disk 34, which is attached to the plug pin 32 above an undercut 39. The latter is used in two variants, namely on the one hand with the press fit shown for both ends - not shown - a slightly conically tapering plug pin 32, 32 _a or the other entirely without a press fit. The above-mentioned transverse bore 30 can receive an unrecognizable stud screw to increase the clamping force of the shaft 12. The central plug pin 32 _a is intended for connection to the dome-like humerus or joint head 40, which on a connection surface 42 for the eccentric disk 34 offers _a recess 44 of the diameter d _λ corresponding to its shape with a central blind bore 46 for the plug pin 32 _a . The bore axis Q ₁ lies here at an axial distance t of 3 mm to the central axis M _{1 of} the joint head 40, and the central axis M of the eccentric disk 34 falls into the cylinder wall of the eccentric bore 46 of the recess 44. Here too, the axial distance t can vary depending on the design correspondingly from 1 mm to 10 mm, preferably up to 8 mm.

The height n ₂ of the spherical head 40 of the joint head 40, which has a polished surface 41, is preferably proportional to the diameter length of the partial spherical surface and measures, for example, somewhat more than 17 mm, the diameter d _{2 of} the joint head 40 here somewhat more than 44 mm.

12 also offers a scale 36 _a oriented to its center Z ₁ , and also a marking triangle 37 on the edge of the recess 44.

13 to 17 show the different settings of the joint head 40 on the shaft 12 thanks to the eccentricity possible through the eccentric disk 34, with E and E _x representing the end face 14 of the shaft 12 and the connecting plane 42 of the joint head 40 certain - in the installed position adjoining - adjustment planes and with F and F _λ revolving circles for the contour 40 _{a of} the joint head 40 and the contour 34 _{a of} the eccentric disc 34 are designated.

The maximum eccentricity towards the outside can be seen in FIG. 13 with t = 6 mm here. With a simultaneous rotation of an adjustment angle y by 45 ° according to FIG. 14 and by 135 ° according to FIG. sitions on the circulation circuit F - with simple eccentricity - occupied. The maximum eccentricity towards the inside is achieved according to FIG. 16 after an adjustment angle of 180 °.

The possibility of continuously rotating the eccentric disk 34 independently of the joint head 40 enables an unlimited number of positions to be approached. Any position within the two circulation circles F, F of FIG. 17 can be set; In this figure the complete zero position can be seen, ie the joint head 40 is concentric in the orbits E, E _± . 13 and 16, the longitudinal axis A of the shaft 12 forms a line of symmetry.

Claims

PATENT CLAIMS

1. Implantable prosthesis with at least two sections that can be adjusted relative to one another, in particular a prosthesis for the upper end of a human upper arm with a shaft (12) that can be inserted into its humeral canal and a dome-shaped joint head (40) that is to be assigned to the joint socket adjacent to the upper arm him as well

Shank each in a hole (16, 46) insertable pin (32) or the like. the washer-like washer (34) of circular circumference (34 _a ) can be connected to an end face (14) of the shaft in an eccentric position with respect to its central axis (M),

characterized,

that the mutually adjustable sections (12, 34, 40) are arranged on at least one adjustment plane (E, E _λ ) against each other to be continuously adjustable about axes (M, M _x ; Q, Q).

2. Prosthesis according to claim 1, characterized in that at least one of the socket pins (32) is arranged at a radial distance (q) to the axis (Q) of the intermediate disc (34).

3. Prosthesis, the washer in an approximately corresponding recess (44) of one of the adjacent sections (14, 42) can be used according to claim 1 or 2, characterized in that the washer (34) with a central plug pin (32 _a ) inserted into a recess (44, 46) corresponding to its shape and eccentrically formed in a connection surface (42) of the joint head (40) and the other, eccentrically attached plug pin (32) is assigned to the end face (14) of the shaft (12).

4. A prosthesis according to claim 3, characterized in that the connection surface (42) determines an adjustment plane (E of the prosthesis (10).

5. A prosthesis according to claim 2 or 3, characterized in that the diameter (d) of the intermediate disc (34) corresponds approximately to half the diameter (d ₂ ) of the joint head (40) and its height (n) approximately the respective height of its socket pins ( 32, 32 _a ).

6. The prosthesis according to claim 5, characterized in that the height (s) of the intermediate disc (34) is approximately one

Corresponds to one third of their diameter (d).

7. A prosthesis according to claim 5 or 6, characterized by a bolt diameter (c _x ), the length of which corresponds to the diameter (d) of its intermediate disk (34), such as 1: 2, 5 to 1: 3.0.

8. Prosthesis according to one of claims 2 to 7, characterized in that the radial distance (q) of the eccentrically provided plug pin (32) from the axis (Q) of the intermediate plate (34) corresponds approximately to half the pin diameter (c).

9. Prosthesis according to one of claims 1 to 8, characterized in that the plug pin (32, 32 _a ) has an annular press-fit region (38).

10. The prosthesis according to claim 9, characterized in that the height (s) of the press fit region (38) corresponds to approximately one tenth to three tenths of the bolt height (n).

11. A prosthesis according to one of claims 1 to 10, characterized in that the socket pin (32, 32 _a ) for the cylindrical blind bore (16, 46) tapers away conically from the washer.

12. Prosthesis according to one of claims 1 to 11, characterized in that the diameter of the plug pin

(32, 32 _a ) measures 1 to 9 mm, preferably 3 to 7 mm.

13. Prosthesis according to one of claims 1 to 12, characterized by a tangential bore (31) for a tangential screw on the blind bore (16, 46).

14. A prosthesis according to at least one of claims 1 to 13, characterized in that the washer

(42) has a diameter (d) of 10 to 35 mm, preferably 3 to 7 mm.

15. Prosthesis according to one of claims 1 to 14, characterized in that the flat recess (44) for the intermediate disc (34) in the joint head (40) is displaced from its central axis (M up to 10 mm, preferably up to 8 mm.

16. A prosthesis according to at least one of claims 1 to 15, characterized in that the disc surface (35) of the intermediate disc (34) and / or the connecting surface (42) of the joint head (40) with a scale assigned to the direction of rotation (36, 36 _a ) are provided.

17. Use of the assignment of adjustable sections (12, 40) and an intermediate disc (34) on an adjustment plane (E, E _λ ) according to at least one of claims 1 to 16 for an elbow, knee or hip joint prosthesis.

18. Use of the assignment of adjustable sections (12, 40) and an intermediate disk (34) on an adjustment plane (E, E _λ ) according to at least one of claims 1 to 16 for a hand or ankle prosthesis.

19. Use of the assignment of adjustable sections (12, 40) and an intermediate disk (34) on an adjustment plane (E, E ₁ ) according to at least one of claims 1 to 16 for a spinal disc prosthesis.