FIXING DEVICE FOR A TIBIA ALIGNMENT SYSTEM

Abstract

A fixing device for a tibia alignment system for knee operations includes a transverse bar, the front end of which can be connected to a main rod of the tibia alignment system. The main rod is configured for an alignment along the tibia. A rear end of the transverse bar has an anchor system with at least one anchor pin that extends obliquely to the transverse bar and can be driven into a knee joint-side end of the tibia. The anchor system has a drive-in anvil into which the anchor pin is integrated and which is designed to transmit impact forces acting on the drive-in anvil from the outside to the anchor pin in order to drive the anchor pin into the tibia. The anchor pin and drive-in anvil are guided in the transverse bar in a longitudinally movable manner.

Claims

1. A fixing device for a tibia alignment system for knee operations, the fixing device comprising: a transverse bar comprising a front end that is connectable to a main rod of the tibia alignment system, said main rod being provided for alignment along a tibia, the transverse bar further comprising a rear end having an anchor system with at least one anchor pin that extends obliquely to the transverse bar and is drivable into a knee joint-side end of the tibia, the anchor system comprising a drive-in anvil for improving fixation of the anchor system to the tibia, the at least one anchor pin being connected to and integrated into the drive-in anvil, the anchor system configured to transmit impact forces acting on the drive-in anvil from outside to the at least one anchor pin in order to drive the at least one anchor pin into the tibia, the at least one anchor pin and drive-in anvil being guided in the transverse bar in a longitudinally movable manner.

2. The fixing device according to claim 1, wherein a drive-in length of the at least one anchor pin is defined by a stop between the drive-in anvil and the transverse bar.

3. The fixing device according to claim 1, wherein said fixing device further comprises an auxiliary device for releasing the drive-in anvil and the at least one anchor pin.

4. The fixing device according to claim 3, wherein the auxiliary device comprises a lever which is mounted or supported centrally on the transverse bar, is hinged, at a lifting end, to the at least one anchor pin or the drive-in anvil or supported therein so as to displace the drive-in anvil relative to the transverse bar in a longitudinal direction of the at least one anchor pin.

5. The fixing device according to claim 3, wherein the auxiliary device comprises a separately provided lever configured to be clamped as single component part between the transverse bar and a base of the anchor system to lever the at least one anchor pin out of the tibia.

6. The fixing device according to claim 4, wherein the lever is hinged to the drive-in anvil or the at least one anchor pin and is supported centrally on the transverse bar.

7. The fixing device according to claim 4, wherein the lever is hinged centrally to the transverse bar and is supported at the lifting end on the drive-in anvil or the at least one anchor pin.

8. The fixing device according to claim 7, wherein the lever and the drive-in anvil are arranged on an upper side of the transverse bar as a different side relative to the at least one anchor pin.

9. The fixing device according to claim 8, wherein: a lower front face of the drive-in anvil facing the tibia and/or the transverse bar is adapted to abut, in a driven-in position of the anchor system, on the upper side of the transverse bar to provide a stop for restricting a drive-in length of the at least one anchor pin; the drive-in anvil forms a step at its lower end for engaging the lifting end of the lever to force the anchor system away from the transverse bar; the lever is designed to be S-shaped and to extend substantially forward and is hinged by a hinge pin, in corresponding hinge eyes formed in an extension and/or a projection on the upper side of the transverse bar; and a handle end of the lever opposed to the lifting end is provided for actuation of the lever.

10. The fixing device according to claim 1, wherein the transverse bar at its front end includes a guide member via which the transverse bar is supportable on the main rod of the tibia alignment system to be freely movable along an axis of the bar.

11. The fixing device according to claim 10, wherein the transverse bar is supportable on the main rod to be freely extractable.

12. The fixing device according to claim 10, wherein a distance of the at least one anchor pin from the main rod is adjustable by support of the transverse bar movable along the axis of the bar so as to adjust a cutting depth.

13. The fixing device according to claim 1, wherein the at least one anchor pin comprises two anchor pins extending in parallel to each other which are connected to the drive-in anvil.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0024] In the following, the present invention is described by way of an example embodiment with the aid of the attached Figures. The Figures are not intended to limit the scope of the present invention but merely serve for illustration purposes.

[0025] FIG. 1 shows a side view of a fixing device according to the invention.

[0026] FIG. 2 shows a rear view of the fixing device of FIG. 1.

[0027] FIG. 3 shows a side view of the fixing device during an operation.

DETAILED DESCRIPTION

[0028] The fixing device 1 shown in FIG. 1 comprises a transverse bar 2 at the front end 3 of which (on the right in FIG. 1) a preferably cylindrical guide is provided through which the transverse bar 2 can be inserted into a corresponding seat A of the main rod H of a tibia alignment system (ETA). At a rear end 4 (on the left in FIG. 1) of the transverse bar 2 an anchor system 5 is provided which includes two anchor pins 6 arranged to be axially spaced in the longitudinal direction of the bar, said anchor pins 6 protruding obliquely, preferably at an angle of 80° to 130°, from the lower side (viewed in FIG. 1) of the transverse bar 2.

[0029] At the top/on a far side of the tibia T (at the top in FIG. 1), the anchor pins 6 are connected to/held on/integrated in/fastened to a drive-in anvil 7 that is disposed on an upper side of the transverse bar 2 and extends upward in the longitudinal direction of the pin. Further, the anchor pins 6 are of different length, in particular the more rearward anchor pin 6 is shorter than the anchor pin 6 at the front.

[0030] A lower front face of the drive-in anvil 7 facing the tibia T and the transverse bar is adapted, particularly beveled, so as to bear on the upper side of the transverse bar 2 in a driven-in position of the anchor system 4 shown here and, thus, to provide a stop 8 for restricting a drive-in length of the anchor pins 6. The drive-in anvil 7 further forms, at its lower end (at the bottom in FIG. 1) a step 9 onto which a lifting end 10 of a lever 11 engages so as to press the anchor system 4 away from the transverse bar 2. For this purpose, the rounded lifting end 10 presses against the step 9. Therefore, the lever 11 acts as an auxiliary device for releasing the drive-in anvil 7 with the two anchor pins 6, 6.

[0031] The lever 11 is S-shaped and extends substantially forward. At a central area of the S-shape of the lever 11, a hinge pin 12 is provided which is inserted in corresponding hinge eyes for forming a hinge point that is configured in an extension/projection 13 on the upper side of the transverse bar 2. The hinge pin 12 is perpendicular but offset to the longitudinal axis of the transverse bar 2.

[0032] As can be seen from FIG. 1, the lever 11 and the drive-in anvil 7 are arranged on the upper side of the transverse bar 2 so that they are located on a different (other) side of the (than the) two anchor pins 6, 6 (i.e., far side of the tibia). Thus, both the hinge point of the lever 11 formed by the hinge pin 12 in the corresponding hinge eyes and a support point of the lever 11 formed between the lifting end 10 and the step 9 are provided on the upper side of the transverse bar 2.

[0033] A handle end 14 of the lever 11 opposed to the lifting end 10 serves as a handle to actuate the lever. The S-shape of the lever 11 ensures sufficient space to be provided between the handle end 14 and the upper side of the transverse bar 2 so that the handle end 14 can be grasped and moved. Upon actuation of the lever 11 by pressing down the handle end 14 toward the upper side of the transverse bar 2, the support point lifts rocker-like in the direction away from the upper side of the transverse bar 2. Accordingly, the line of movement of the support point will not cross the longitudinal axis of the transverse bar 2. Thus, the actuation, respectively, the kinematic course of movement of the lever 11 takes place on the side of the transverse bar 2 far from the two anchor pins 6, 6, i.e. far from the tibia, and in a space above the upper side of the transverse bar 2.

[0034] FIG. 2 illustrates a rear view of the afore-described fixing device 1. It is evident from FIG. 2 that the drive-in anvil 7, the lever 11, the transverse bar 2 and the anchor pins 6 are arranged in a line symmetrically to each other, respectively, symmetrically to a plane of symmetry that extends in the vertical direction, as viewed in FIG. 2. In particular, the bifurcated lifting end 10 is shown which, in the area of the step 9, encompasses the drive-in anvil 7 to press upward against the step 9. At its front face 8, the drive-in anvil 7 abuts on the rear end 4 of the transverse bar 2 to restrict the drive-in length of the anchor pins 6. Further, the transverse bar 2 is sufficiently narrow at a rear end so that it can be located between the tines/jaws of the bifurcated lifting end 10. Thus, easy handling and mounting of the lever 11 is ensured.

[0035] The view shown in FIG. 3 substantially corresponds to a simplified representation of the embodiment of the fixing device 1 according to the invention of FIG. 1, but it illustrates the fixing device 1 when it is utilized in a knee operation. It can be seen in more detail that the anchor pins 6 which are retained at the rear end 4 of the transverse bar 2 are driven from above (as seen in FIG. 3) or frontally into an upper front face of the tibia T. The transverse bar 2 is thus fixed to the tibia T. The transverse bar extends forward in the direction of the main rod H and is guided on the latter movably along the bar axis.

[0036] On the main rod H extending substantially in parallel to the tibia T, a cutting block S, respectively, a saw jig or saw holder is held to be movable along the main rod H. If the cutting block S is to be displaced downward, with a rigid connection of the main rod H and the transverse bar 2, the cutting block would abut against or rub along and damage a part of the tibia T, as is clearly visible in this schematic view. As, however, the main rod H or at least the upper end thereof is movable forward along the fixed transverse bar 2, it is possible to space apart to this one jointly with the cutting block S from the tibia T. Subsequently, the cutting block S is movable (slidable) along the main rod H without any risk of injuring the tibia T.

[0037] In order to extract, after fixing the cutting block S, the pins from the front face of the tibia T, the lever 14 can be pressed down to pull the drive-in anvil 7 and the anchor pins 6 arranged/held thereon upwards relative to the tibia T and the transverse bar 2. As the anchor pins 6 are movable (slidable) along the pin axis in the transverse bar 2, the transverse bar 2 and the main rod H can remain fixed, as described in detail before, and the connection of the cutting block S/the saw jig to the main rod H need not be simultaneously released.