Surgery – Instruments – Orthopedic instrumentation
Reexamination Certificate
2000-03-28
2001-07-31
Philogene, Pedro (Department: 3732)
Surgery
Instruments
Orthopedic instrumentation
C606S056000, C606S057000, C606S088000, C606S08600R
Reexamination Certificate
active
06267762
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for the positioning of a proximal extremity of a tibia against a cutting guide, so that the cutting guide can guide a saw blade in cutting the tibia following a given resection plan, in order to install a knee prosthetic.
2. Description of the Related Art
Devices for positioning of this type are already known from the former art. They generally include a support bracket and means of distally immobilising a tibia In a given position, where those means are implemented so that they may slide along the support bracket and be securely held in place, following at least one direction, preferably two perpendicular directions, within a perpendicular plane. They also generally include means of proximally immobilising a tibia in a given position, where those means are implemented so that they may slide longitudinally along the support bracket Finally, they also include a cutting guide implemented on the support bracket.
These devices known from the former art feature several inconveniences,
The chosen resection plan takes into account the inclination of the tibia in both the ante-posterior plane as well as the inclination of the tibia in the frontal plane. When positioning the cutting guide with regard to the immobilised tibia, it is therefore necessary to be able to adjust the angle between the support bracket and the tibia within the sagittal plane (posterior slope) and also the angle between the support bracket and the tibia within the frontal plane (varus valgus). However, in order for these adjustments, as well as adjusting the height of the cutting guide to take place, these devices known from the former art consist of a great number of assembling components, complicated and difficult to manipulate.
BRIEF SUMMARY OF THE INVENTION
The invention aims to remedy those inconveniences, notably with a positioning device of the type described previously, which would be easier to grasp and manipulate, especially when adjusting the inclination of the tibia within the frontal and posterior planes and also when adjusting the height of the cutting guide with regard to the tibia.
The device for positioning the proximal extremity of a tibia with regard to a cutting guide according to the invention, is characterised in that it includes a gun handle with a hammer and a trigger fixed to the support bracket. The hammer acts on devices that allow the adjustment of the relative position of the immobilising devices with regard to the support bracket, with the possibility of blocking. The trigger acts on devices that allow the adjustment of the angle (posterior slope) between the support bracket and the tibia within the sagittal plane.
As a gun handle with a-hammer and a trigger is implemented, the device enables the surgeon to position the tibia with regard to the cutting guide in a simple manner. The positioning of proximal immobilising devices is simply done by the use of the hammer and sliding those devices along the support bracket, once the appropriate position has been reached, the hammer is released, which then blocks the proximal immobilising devices in place with the chosen resection plan facing the cutting guide. The trigger is depressed next which enables the adjustment of the posterior slope of the tibia and then released to block the adjusted value of the posterior slope. Finally, without using neither the hammer nor the trigger, the handle is used to adjust the angle of (varus valgus) by sliding within the frontal plane.
According to an aspect of the present invention, the devices that adjust the angle between the tibia and the support bracket in the sagittal plane consist of a lever, an extremity of which co-operates with a pushing component, the inferior extremity of which features gears which themselves couple with the gears of a supporting arm. The action of depressing the trigger de-couples the gears of the pushing component from the gears of the supporting arm and by releasing the trigger, couples those same gears in order to adjust the angle between the support bracket and the tibia in the sagittal plane. The device according to this improvement is of a simple assembly.
According to a further aspect of the present invention, the supporting arm includes a plate which slides within a rail that is formed within a support of the distal immobilising devices of the tibia. The sliding action takes place with the possibility of blocking by way of the co-operation between an ergot and regularly spaced notches that have been implemented on the guiding rail. The notches successively receive the ergot to enable the blocking of the plate with regard to the distal immobilising devices in order to adjust the angle between the tibia and the support bracket within the frontal plane (angle of varus/valgus).
According to a further aspect of the present invention, the proximal immobilising devices of the tibia include a stem which can slide within the support bracket, and which includes notches that couple with gears of a first pushing piece, the moving of which is acted by the hammer. Depressing of the hammer de-couples the gears of the piece from the notches of the stem, so that the stem may slide with regard to the support bracket. Suspending the action of depressing the hammer couples the gears of the piece with the notches, so that the stem is blocked in place with regard to the support bracket, therefore the proximal immobilising devices with regard to the tibia is blocked into place.
According to a further aspect of the present invention, the number of notches on the supporting arm relates to a pre-determined bracket of adjustment, based on the angle of the posterior slope, ie between zero degrees and eight degrees.
According to a further aspect of the present invention, the number of notches on the guiding rail relates to a predetermined bracket of adjustment, based on the angle of varus valgus, ie between three degrees and minus three degrees.
According to a further aspect of the present invention, the cutting guide may slide vertically with regard to the support bracket and, being blocked as for rotation, do so independently from the proximal immobilising devices. This enables an even finer adjustment of the position of the cutting guide, therefore a finer adjustment of the position is obtained for the resection of the tibia.
REFERENCES:
patent: 5628749 (1997-05-01), Vendrely et al.
patent: 5628750 (1997-05-01), Whitlock et al.
patent: 5643272 (1997-07-01), Haines et al.
patent: 5968043 (1999-10-01), Ross, Jr. et al.
patent: 6090114 (2000-07-01), Matsuno et al.
Biegun Jean-François
Millard Thierry
Aesculap
Philogene Pedro
Renner Kenner Greive Bobak Taylor & Weber
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