DE19820721A1 - Instrument for handling components of joint prostheses - Google Patents

Abstract

To facilitate the insertion of an inserting shell into an outer shell of a two-part joint socket prosthesis, the invention provides for an instrument (1) which consists of a handle (3) and a holding tool (4) joined to same. The holding tool (4) comprises at least two grasping claws (5) which extend substantially radially (7) in relation to the longitudinal axis (6) of the handle (3). The grasping claws (5) contact the front face (15) of the inserting shell (2). The grasping claws (5) comprise hooks (8) which each extend beyond the narrowing exterior surface (9) of the inserting shell (2) by the same length (10) and such that they can be released when pressure is applied onto the inserting shell (2). A hole (17) in which a plunger protruding from the handle (3) is mounted in a sliding manner extends through the handle (3) concentrically to its longitudinal axis (6). When the plunger (16) is slid in the direction (20) of the inserting shell (2) said shell is pushed out of the holding tool (4).

Description

The invention relates to an instrument for handling and inserting a Insert shell in an outer shell of a two-part acetabular prosthesis according to the preamble of the first claim.

Joint prostheses, in which one joint partner acts as a socket and the other Joint partner is designed as a ball head, which is rotatably mounted in the pan are known in particular as shoulder and hip joint prostheses. This Prostheses are generally modular. That means, for example the socket is in two parts and consists of an outer shell, which in the Bone is inserted and from an insert shell into the outer shell is used and the joint surface, the sliding surface for the other Joint partner. The insertion of the insert shell in the outer shell usually takes place by means of a press fit. For this it is necessary that the Insert shell must be aligned very precisely to the outer shell in order to Avoid jamming. When tilted insertion, except for an inaccurate assignment of the articular surface to the ball head Damage to the insert shell occurs. In particular insert shells Ceramic can break out or even break.

If the insert tray is inserted by hand by the surgeon, it is Handling in the area of the surgical wound due to the Body fluids wet surgeon's and bad gloves Clarity difficult. Because of this, it is known to be instruments to be easier to handle with the insert shells to be used should. From the German utility model DE 297 02 093 U1 is a Known handling instrument of joint components with joint surfaces, which has a grip part and a suction element arranged on the end thereof,  which is a self-contained, attached to the articular surface of the articular component sealingly put on and with this articular surface a sealed suction chamber forming sealing element and a pressure of the suction chamber lowering device. This Handling instrument is placed on the joint surface of the sealing element insert tray to be used, the pressure in the suction chamber lowered and thereby sucked the insert shell. After inserting the Insert shell, the pressure is increased again and the handling instrument releases automatically from the insert shell used.

The known handling instrument offers no security that the Insert shell with the required accuracy placed on the outer shell and thereby tilting can be avoided. Besides, they are known handling devices long (up to 40 cm). This makes them unwieldy and thus lack the required sensitivity during the insertion process.

The present invention has for its object an instrument for Handling and for inserting an insert shell into an outer shell to introduce two-part acetabular prostheses with which a light Position and a tilt-free insertion is possible.

The task is solved with the help of the characteristic features of the first claim. Advantageous embodiments of the invention are in the Claimed claims.

The instrument according to the invention for handling and inserting a Insert shell in an outer shell of a two-part acetabular prosthesis consists of a handle with an attached holding tool. By the handle can be easily handled by the holding tool for the insert shell. The holding tool has at least two gripping claws. These extend essentially radial to the longitudinal axis of the handle. The claws of the gripping claws  lie on the front circumferential surface of the insert shell to be used. Due to the arrangement of the gripping claws and their claws, the insert shell becomes exactly centered on the longitudinal axis of the handle and perpendicular to this axis kept aligned. This will provide the surgeon with precise alignment the insert shell possible when inserting. The short design of it Instruments also offers the surgeon the necessary sensitivity when Insertion process.

The claws of the gripping claws grip the tapered outer surface of the Insert shell in the same length so far that on the one hand a safe On the other hand, keep it easy to eject from the claws is. Ejecting the insert shell from the gripping claws of the holding tool takes place by means of a plunger which is slidably mounted in a bore concentric to the longitudinal axis of the handle. When moving the ram in the direction of the insert shell, this becomes from the claws of the gripping claws pushed out and can be in the outer shell of the acetabular prosthesis be pushed in.

In one embodiment of the invention, the claws of the gripping claws face perpendicular to the longitudinal axis. These end faces serve to be placed on the face of the outer shell. Since the claws on the Gripping claws are all the same length is when all claws are placed on the Face of the outer shell, the insert shell exactly for their use positioned. This configuration of the gripping claws is an advantageous aid for the surgeon with whom he is in the difficult environment of the surgical wound can position the insert shell securely and precisely for use.

So when positioning the instrument with the insert shell on the The outer shell has not adversely affected the position of the insert shell The length of the claws should be dimensioned at least so that when it is placed on the Face of the outer shell, the insert shell held by them still does not  Has clamp contact with the outer shell. This is a correction of the Positioning possible at any time. This is complete when all claws are with their end faces rest on the end face of the outer shell.

In a further embodiment of the invention, the claws are made of an elastic Material, so that the insert shell is easily removed from the holding tool can be squeezed out. Another advantage is that insert shells that differ only slightly in their diameters, from one and that same holding tool can be held.

In another embodiment of the invention, the claws are the gripping claws made of an elastic material. Especially with instruments that used only once, the claws can be designed so that they are when pressing the insert shell out of the gripping claws, it even remains deform.

In a further advantageous embodiment of the invention, the handle has a Recessed grip. This recessed grip enables, for example, the clamping of the Handle between two parallel fingers, for example the middle and the Ring finger or the index and middle finger. The recessed grip can For example, be U-shaped and run around the entire handle so that one optimal storage of the instrument in the surgeon's hand in every possible Alignment is possible. The insert shell can then be pressed out for example by means of the thumb or the ball of the hand.

So that the plunger does not come out when the insert shell is ejected from the gripping claws exerting selective stress on the insert shell, it is advantageous to be End has at least one plate with which it is ring-shaped on the Insert shell supported. Such a plate has the advantage that the plunger for Insert shells with different joint surface diameters can be used.  

In another embodiment of the invention, the plunger has at its end a stamp head adapted to the articular surface of the insert shell. Of the The stamp head then has the shape of a spherical cap, the radius of which corresponds to the radius of the Articular surface corresponds. Such a plunger is only for one diameter an insert shell can be used, but has the advantage that it is at Apply force to be applied evenly and over a large area Insert shell distributed.

The insert shell is usually pressed into the outer shell by the surgeon manually. However, one can still be used for final fixation subsequent impact with an impact tool may be required. In one In such a case, the instrument according to the invention also offers a possibility to apply such a fixation strike specifically to the insert shell. By the exact alignment of the instrument to the outer shell and thus the Insert shell to the outer shell are those brought up by the blow Forces evenly and precisely according to their purpose in the insert shell initiated.

The invention is explained in more detail using an exemplary embodiment.

Show it:

Fig. 1 with an instrument to be inserted insert shell in the holding tool of the invention,

Fig. 2 shows a section along the axis through the handle of the instrument, as shown in the figure, and

Fig. 3 is a sectional view corresponding to FIG. 2 with a further embodiment of the plunger.

The illustration in the figures takes place on an enlarged scale. In FIG. 1, 1 denotes the instrument according to the invention for handling and inserting the insert shell 2 held by it. The instrument 1 consists of a handle 3 and a holding tool 4 . In the present exemplary embodiment, the holding tool 4 has three gripping claws 5 which extend essentially radially from the longitudinal axis 6 of the handle 3 . This can be seen from the right angle 7 in the sectional view of FIG. 2. In the present exemplary embodiment, the gripping claws are arranged at equal angular intervals α, but this is not absolutely necessary.

The gripping claws 5 have claws 8 which overlap the tapering outer surface 9 of the insert shell 2 . In order to take into account the taper of the outer surface 9 of the insert shell 2 , the claws 8 each have an undercut 13 . The claws 8 all have the same length 10 . So that an exact positioning and alignment of the insert shell 2 to the outer shell is possible, the contact surfaces 14 of the gripping claws 5 , which lie on the end face 15 of the insert shell 2, are perpendicular to the longitudinal axis 6 of the handle 3 . Their extension cuts the axis 6 at a right angle 7 , as shown in Fig. 2. This enables the instrument to be placed precisely against the end face of the outer shell, as can be seen from FIG. 2.

In the present exemplary embodiment, the gripping claws 5 are elastic, so that when the insert shell 2 is pressed in the direction out of the instrument 1 , the claws 8 are bent outwards and release the insert shell 2 .

The expressions of the insert shell 2 from the retaining tool 4 takes place by means of a plunger sixteenth The plunger 16 is mounted in a bore 17 which runs concentrically to the longitudinal axis 6 in the handle 3 . At its end facing the insert shell 2 , the plunger 16 carries a plate 18 in the present exemplary embodiment. This lies with its outer circumference 27 in a ring on the hinge surface 19 of the insert shell 2 . The contact surface is concentric with the longitudinal axis 6 of the handle 3 , as can be seen in FIG. 2. This ensures a uniform introduction of the pressure force into the insert shell 2 . If a force is exerted on the plunger 16 in the direction of the arrow 20 , the gripping claws 5 release the insert shell 2 due to their elasticity.

The handle 3 has a U-shaped recessed grip 21 which rotates centrally around the handle. It is designed so that the handle can be held in particular between two parallel fingers. It is then possible to press the end face 22 of the plunger 16 by means of the ball of the hand or with the thumb and to press the insert shell 2 out of the holding tool 4 . A cap 23 on the end face 22 of the plunger 16 has a diameter such that the plunger cannot slide through the bore 17 when the insert shell 2 is pressed into the outer shell. In addition, this cap 23 protects the shaft 22 in the event of an impact with a striking tool and thus prevents the front edges of the plunger 16 from flaking or splintering.

FIG. 2 shows a longitudinal section through the instrument 1 and the insert shell 2 held by it in the positioning position on an outer shell 24 . The course of the cut is drawn in Fig. 1 with II-II. It runs through two adjacent gripping claws 5 .

In FIG. 2, the instrument 1 with the insert shell 2 held by it, with the end faces 11 of the claws 8, is placed on the end face 25 of the outer shell 24 . The insert shell 2 is positioned in the outer shell 24 . When all end faces 11 of the claws 8 are placed on the end face 25 of the outer shell 24 , exact centering and positioning of the insert shell 2 is ensured.

As can be seen from the sectional view, the claws 8 overlap the outer surface 9 of the insert shell 2 in their edge region in the same length 10 . This length corresponds to the length of the claws 8 . The length 10 of the claws 8 is selected so that when their end faces 11 lie completely on the end face 25 of the outer shell 24 , there is still no clamping contact between the outer surface 9 of the insert shell 2 and the inner surface 26 of the outer shell 24 .

Only when the plunger 16 is actuated by a force acting in the direction of the arrow 20 will the gripping claws 5 release the insert shell 2 due to their elasticity. In the present exemplary embodiment, the plunger 16 carries, at its end facing the insert shell 2, a plate 18 which lies on its outer circumference 27 in a ring on the hinge surface 19 of the insert shell 2 . By force acting in the direction of arrow 20 on the plunger 16 , the insert shell 2 is pressed into the outer shell 24 after being released by the holding tool 4 . Due to the conicity of the outer surface 9 of the insert shell 2 and the inner surface 26 of the outer shell 24 , an interference fit takes place.

In FIG. 3, which shows a sectional view corresponding to FIG. 2, the plunger 16 carries at its end facing the insert shell 2 a stamp head 28 adapted to the articular surface 19 . In this exemplary embodiment, similar features are designated with the same reference symbols. The stamp head 28 has the shape of a spherical cap and its surface 29 corresponds exactly to that of the joint surface 19 of the insert shell 2 . In this embodiment, a large-area and uniform introduction of the force into the insert shell 2 is possible.

The instrument 1 for handling an insert shell 2 can be made from a sterilizable material, for example from a heat and chemical resistant plastic or from a metal with the same properties, so that reuse is possible. However, the instrument can also be viewed as a disposable tool that is disposed of after use. In this case, it is possible to provide the surgeon with a sterile package together with an instrument that already holds the insert shell with its holding tool. This eliminates the manual insertion of the insert shell into the holding tool of the instrument during the operation, which simplifies the surgeon's working conditions and prevents damage to the sensitive joint surface of the insert shell.

Claims (9)

1. Instrument for handling and inserting an insert shell into an outer shell of a two-part acetabular prosthesis with a holding tool for detachably holding the insert shell to be inserted, characterized in that the instrument ( 1 ) consists of a handle ( 3 ) and an adjoining holding tool ( 4 ) that the holding tool ( 4 ) has at least two gripping claws ( 5 ), that the gripping claws ( 5 ) extend essentially radially ( 7 ) from the longitudinal axis ( 6 ) of the handle ( 3 ), that the gripping claws ( 5 ) rest on the end face ( 15 ) of the insert shell ( 2 ) such that the gripping claws ( 5 ) have claws ( 8 ) which overlap the tapering outer surface ( 9 ) of the insert shell ( 2 ) in the same length ( 10 ) so far that the insert shell ( 2 ) is released with a pressure force exerted on it so that a bore ( 17 ) runs through the handle ( 3 ) concentrically with its longitudinal axis ( 6 ), in a plunger ( 16 ) protruding from the handle ( 3 ) is slidably mounted, and that when the plunger ( 16 ) is moved in the direction ( 20 ) onto the insert shell ( 2 ), it can be pressed out of the holding tool ( 4 ). 2. Instrument according to claim 1, characterized in that the claws ( 8 ) of the gripping claws ( 5 ) of the holding tool ( 4 ) perpendicular ( 12 ) to the longitudinal axis ( 6 ) of the handle ( 3 ) extending end faces ( 11 ) for placement on the end face ( 25 ) of the outer shell ( 24 ). 3. Instrument according to claim 1 or 2, characterized in that the length ( 10 ) of the claws ( 8 ) is dimensioned at least so that when the device ( 1 ) is placed on the end face ( 25 ) of the outer shell ( 24 ) the conical outer surface ( 9 ) the insert shell ( 2 ) has no clamping contact with the inner surface ( 26 ) of the outer shell ( 24 ). 4. Instrument according to one of claims 1 to 3, characterized in that the gripping claws ( 5 ) of the holding tool ( 4 ) consist of an elastic material. 5. Instrument according to one of claims 1 to 3, characterized in that the claws ( 8 ) of the gripping claws ( 5 ) of the holding tool ( 4 ) consist of an elastic material. 6. Instrument according to one of claims 1 to 5, characterized in that the handle ( 3 ) of the instrument ( 1 ) has a recessed grip ( 21 ). 7. Instrument according to claim 6, characterized in that the recessed grip ( 21 ) is U-shaped and circumferential. 8. Instrument according to one of claims 1 to 7, characterized in that the plunger ( 16 ) at its end facing the insert shell ( 2 ) has a plate ( 18 ) which is concentric with its outer circumference ( 27 ) on the articular surface ( 19th ) the insert shell ( 2 ) can be put on. 9. Instrument according to one of claims 1 to 8, characterized in that the plunger ( 16 ) at its end facing the insert shell ( 2 ) carries an articulated surface ( 19 ) adapted stamp head ( 28 ).