CUTTER

A surgical cutter intended in particular for the prosthetic replacement of a knee ligament and comprising a blade-holder tube provided with a handle at one of its ends, a blade of generally rectangular shape mounted pivotably, at the other end of said blade-holder tube, about a rotation axis perpendicular to the longitudinal axis of the latter between a “retracted” position, in which it does not protrude from the body of said blade-holder tube, and a “deployed” position, in which it extends on each side of said blade-holder tube, and a locking mechanism for locking said blade in the “retracted” position or “deployed” position.

FIELD OF THE INVENTION

The present invention relates to a multipurpose surgical instrument particularly for the plasty (or prosthetic replacement) of a knee ligament.

PRIOR ART

In the case of a ligament rupture, following an accident for example, it is well-known that it may be necessary to replace the damaged ligament(s) which, in the case of some, cannot regenerate themselves.

The difficulty in replacing this type of ligament is no longer associated with the ligaments themselves since very suitable artificial ligament embodiments are now known, but with restricted accessibility problems due to the particularly overcrowded anatomy of the joints, as well as with problems associated with artificial ligament holders, i.e. the anatomic parts wherein and on said ligament is sought to be mounted.

Indeed, in order to mount and insert the ligament, it is necessary to produce tunnels (drill holes) in some anatomical parts such as the femur and tibia. However, in view of the mechanical strength of these anatomical parts, it is important to minimise the number and dimensions of these tunnels, particularly the diameter thereof, so as not to weaken said anatomical parts.

DESCRIPTION OF THE INVENTION

Therefore, the aim of the present invention is that of remedying these drawbacks by providing a multipurpose surgical instrument, used in particular for the plasty (or prosthetic replacement) of a knee ligament, of compact design, easy to use and suitable for only increasing the diameter of a tunnel produced in an anatomical part locally, particularly and essentially at the inaccessible end of said tunnel opening into a joint cavity.

In this regard, the present invention relates to a surgical cutter intended in particular for the plasty (or prosthetic replacement) of a knee ligament and comprising:a blade-holder tube provided with a handle at one of the ends thereof,a blade of generally rectangular shape mounted pivotably, at the other end of said blade-holder tube, about a rotation axis perpendicular to the longitudinal axis thereof between a “retracted” position wherein it does not protrude from the body of said blade-holder, and a “deployed” position, andlocking means suitable for locking said blade in the “retracted” position or “deployed position, said cutter being characterised in that the blade rotates freely when it is not locked by the locking means and in that it extends on either side of said blade-holder tube when it is in the “deployed” position.

Advantageously, the blade-holder tube is a hollow tube and comprises:a slot traversing therethrough and suitable for receiving the blade when it is oriented such that the longitudinal axis thereof is aligned with the longitudinal axis of said blade-holder tube, andan orifice traversing therethrough and being arranged such that the longitudinal axis thereof is perpendicular to the longitudinal plane of symmetry of the slot and passes through the centre of said slot, said orifice being suitable for engaging with a rivet to enable the blade to pivot about the longitudinal axis thereof.

The blade is preferably a sheet of generally rectangular shape wherein the thickness is strictly less than the thickness of the slot of the blade-holder tube, the width is at most equal to the diameter D of the blade-holder tube and the length is strictly greater than said diameter D, and said blade further comprises a central orifice traversing through the thickness thereof and suitable for engaging with the rivet to enable the pivoting thereof about the longitudinal axis of said orifice.

According to one preferred embodiment, the locking means comprise a shaft wherein one of the ends is suitable for engaging with the blade and a locking member fastened to the other end of said shaft, suitable for engaging with the end of the blade-holder tube, opposite that receiving the blade, in order to slide said shaft inside the blade-holder tube and lock same in a defined position.

The blade advantageously comprises cut-out sections situated at the midpoint of the lateral and longitudinal edges thereof.

The end of the shaft is then suitable for engaging with one of the cut-out sections of the blade.

Preferably, the locking member is rigidly connected to the end of the blade-holder tube by a helical link and in that it comprises a cap provided with an internal or external thread suitable for engaging with an internal or external thread produced on the associated end of the blade-holder tube.

PREFERRED EMBODIMENT OF THE TECHNICAL INVENTION

InFIGS. 1 to 6, a surgical cutter1, according to the invention, has been represented, comprising a hollow blade-holder tube2provided at one of the ends thereof with a handle3, a flat blade4of generally rectangular shape mounted pivotably at the other end of said blade-holder tube2about an axis of rotation perpendicular to the longitudinal axis thereof and locking means5suitable for locking said blade4in position.

The term “generally rectangular” denotes herein a shape which may be rectangular in the strict sense with a right angle at each vertex or indeed a rectangular shape with a rounded corner at each vertex optionally ranging up to an oblong shape.

The blade-holder tube2, which extends beyond the handle3, is a tube with a circular cross-section and comprises:a slot21traversing therethrough and suitable for receiving the blade4when it is oriented such that the longitudinal axis thereof is aligned with the longitudinal axis22of said blade-holder tube2, andan orifice23traversing therethrough and being arranged such that the longitudinal axis231thereof is perpendicular to the longitudinal plane211of symmetry of the slot21and passes through the centre of said slot21.

Said orifice23being suitable for engaging with a rivet6to enable the blade4to pivot about the longitudinal axis231thereof.

The blade4is a sheet of generally rectangular shape wherein the thickness is strictly less than the thickness of the slot21of the blade-holder tube2, the width is at most equal to the diameter D of the blade-holder tube2and the length is strictly greater than said diameter D.

The blade-holder tube may have a non-circular cross-section without leaving the scope of the present invention, the diameter D will then correspond to the size of said blade-holder tube2situated in the longitudinal plane of symmetry of said slot.

Said blade4further comprises a central orifice41traversing through the thickness thereof and suitable for engaging with the rivet6to enable the pivoting thereof about the longitudinal axis231of said orifice23between a “retracted” position wherein the blade4is oriented such that the longitudinal axis thereof is aligned with the longitudinal axis22of said blade-holder tube2(seeFIG. 4) and a “deployed” position wherein the blade4is oriented such that the longitudinal axis thereof is perpendicular to said longitudinal axis22(seeFIG. 6), the blade4only protruding from the blade-holder tube2when it is in the “deployed” position wherein it extends on either side of said blade-holder tube2.

Moreover, the blade4also comprises cut-out sections42,43situated at the midpoint respectively of the lateral44and longitudinal45edges thereof, said cut-out sections42,43being preferably semicircular in shape. However, said cut-out sections42,43may be of any other shape such as, for example, square, rectangular or triangular, without leaving the scope of the present invention.

The cutter1according to the invention also comprises locking means5suitable for locking said blade4in the “retracted” position or “deployed position. Said locking means5comprise a shaft51wherein one of the ends is suitable for engaging with the cut-out sections42,43of the blade4and a locking member52fastened to the other end of said shaft51, suitable for engaging with the end of the blade-holder tube2, opposite that receiving the blade4, in order to slide said shaft51inside the blade-holder tube2and lock same in a defined position.

Said locking member52is therefore rigidly connected to the end of the tube-holder blade2by a link enabling the relative displacement of the locking member52with respect to the blade-holder tube2at least along the longitudinal axis thereof. For reasons of ease of cleaning, said link is preferably a helical link and the locking member52is in this case a cap521provided with an internal thread522suitable for engaging with an external thread24produced on the associated end of the blade-holder tube2.

The cap521of the locking member52may be provided with an external thread suitable for engaging with an external thread produced on the associated end of the blade-holder tube2, without leaving the scope of the present invention.

As such, with reference toFIGS. 4 to 6and with this surgical cutter1design, according to the invention, the procedure described hereinafter is applied to produce a counterbore in an existing tunnel (or pre-tunnel) so as to increase the diameter of said tunnel locally.

First of all, after having produced a pre-tunnel of a slightly greater diameter than the diameter of the blade-holder tube2in the tibia and the femur, observing a correct alignment with no angulation, the femoral tunnel, followed by the tibial tunnel, will be prepared.

For this, under arthroscopic monitoring, the blade-holder tube2of the cutter1, wherein the blade4is locked in the “retracted” position by the locking means5, is inserted.

Then, when the end of the cutter1is in the joint cavity, insertion is continued by approximately some ten millimetres beyond the end of the pre-tunnel opening into said cavity.

At this stage, the blade4is released by unfastening the cap521of the locking member52slightly from the associated end of the blade-holder tube2such that the end of the shaft51is no longer engaged in the associated cut-out section42, conventionally by a rotation in the anti-clockwise direction.

Then, using a spindle or optionally an arthroscopic instrument, the blade4is pivoted about the longitudinal axis231of the orifice23of the blade-holder tube2until it reaches the “deployed” position.

Next, the blade4is locked in this position by refastening the cap521of the locking member52onto the associated end of the blade-holder tube2such that the end of the shaft51is engaged into the associated cut-out section43, conventionally by a rotation in the clockwise direction.

Finally, the cutter1is pulled outwards, using the handle3by making rotation movements, thereby boring the tunnel of a length and a diameter suitable for the chosen surgical procedure.

Finally, the blade4is unlocked once again, pivoted to return it to the “retracted” position thereof, locked once again and removed from the femoral tunnel.

If required, after selecting the cutter, the same procedure is applied to produce the tibial tunnel to dimensions suitable for the chosen surgical procedure.

INDUSTRIAL APPLICABILITY

It is understood that the cutter1, according to the invention, is more particularly suitable for the plasty (or prosthetic replacement) of a knee ligament, but it may also be used for other types of surgical procedure.

Finally, it is obvious that the present invention is not restricted to the sole embodiment of this cutter1; on the contrary, it encompasses all alternative embodiments and applications observing the same principle.