FR2708462A1 - Instrumentation of recovery of total hip prosthesis. - Google Patents

Abstract

The present invention is a device for implementing a method of revising a total hip prosthesis (P.T.H.) when the latter was cemented. This process allows the ablation of the stem of the original total hip prosthesis, the excision of the residual cement, to perforate the surgical cement plug in its center, whatever the initial position of the removed prosthesis (varus or valgus), by the combination of an alignment or centro-medullary sight, of bits and burs of particular shapes so as to penetrate and advance in said surgical cement only under the effect of a force (pressure) and all carried and guided by a sighting gun preventing their scanning in contact with said surgical cement. The field of application of the invention is in the field of orthopedic surgery.

Description

DESCRIPTION
The present invention relates to a device for implementing the method of recovery of total hip prosthesis. It is composed of a series of instruments allowing to successively carry out the operations of ablation of the femoral stem, the excision of its coat of surgical cement or PMMA and the intramedullary plug.

 The technical field of the invention is in the medical field and more particularly in the field of orthopedic surgery where the risk of fracturing the femur during PTT occasions. is important and where the operative time and therefore anesthesia is very long.

 The main application of the invention is the respect of the integrity of the long bone which receives the prosthetic stem during the ablation thereof and during the removal of the surgical cement which was an interface between the bone and the bone. metal of the stem.

 Indeed, until then, the surgeon only has instruments that are poorly adapted to physiology: 1 / Material unsuitable for ablation of the stem: chisels, needles, hammers to hit under the prosthetic stem.

2 / Viewers that take the axis of the stem from where it may come out through the bone if the prosthesis is placed in varus or valgus.

3 / Helical drills that have two major disadvantages, the first is due to the heating of the surgical cement or P.M.M.A. which "stuffs" and "sticks" to the wick therefore causes a spiral fracture of the femur at the level of the lower plug, the second is due to the helical threads that cause the wick to undergo an uncontrollable penetration during the rotation of the latter. where there is a risk of crossing the bone if the wick is not in the exact axis of the femur and unable to attack the cement at an angle.

 Of all these facts, the operating time and therefore anesthesia is all the longer.

 The problem thus posed is to have a universal extractor of prosthetic stems, a complete instrumentation comprising a sighting tool or centromedullary alignment on the anatomical axis of the femur, and strawberries and wicks which make it possible to make chips in the cement without heating to avoid the phenomenon of sticking and which can not sink in the cement with a pressure phenomenon on the part of the surgeon to avoid the phenomena of uncontrollable penetration and that the locks and the strawberries all are guided by sighting cannons (Fig. 11, 18 and 20).

 The solutions proposed to these problems respond to a method and a device for implementing the method of recovery of total hip prosthesis which by its ease of use and its reliability will save time and safety for the surgeon and the patient. anesthesiologist and, therefore, to the patient.

 Each operating phase has its own specific tools: a - Ablation of the original total hip prosthesis stem with a universal tool (Fig. 1). It is a room equipped at its upper part with a gimbal system (14). On this gimbal is screwed a rod (15) surmounted by a fixed stop (17), a rod on which slides a feeder (16) whose impact against the stop allows to remove the stem of the hip prosthesis. The cardan has several degrees of freedom to respect the longitudinal axis of the femur (Figs 1,2 and 3).

 This part (A) equipped with the gimbal (13) (FIG 3) is perforated in the axis (x, y) of the universal joint by an opening (7) whose cut is spherical, preferably shaped heart whose tip is directed towards the back. The distance between the tip of the heart and the posterior surface of the piece is lower at the bottom than at the top, so as to catch the taper of the Morse taper.

 Another opening (8) is made in the room, perpendicular to the first. In this hole is housed a key (9) (Figures 4 and 5) whose purpose is to fit on the morse taper of the prosthesis (10) to secure the stem of the hip prosthesis with the extractor (1) (Fig. 2).

 In order to block all types of existing hip prosthesis cones (10) and in a particular embodiment, we have made several keys (9), whose opposite faces, upper and lower have an angle defined according to the type cone to extract, striated on their lower parts and pulled by a threaded rod (11) from locking the cone to the workpiece by the action of the nut (12).

b - The drilling of the first cavity (Fig. 8,9 and 10) is done by a tool (Fig. 11 and 12) of elongated shape (18) whose end is refined so that it can penetrate into the hole ( 20) left after removal of the original prosthesis (Fig. 6,7,9 and 10).

 Said end is recessed (21) so as to allow the cutter (43 and 22) carried by its rod (23) to penetrate inside the tool (18) (Fig. 12 and 13) so that in a neutral position , the bur is entered inside the tool (18).

c - The centromedullary alignment (Fig. 6) is also obtained without using phase b, directly by one of the olives (13) of increasing size from 4 to 20 mm of O sunk into the light (20) left during extraction the femoral element.

 The type of olive is chosen according to the diameter of the opening in which it is pressed. The olive is attached to the end of a solid rod (27) serving as a guide to the cutter (28) attached to the end of a hollow rod (31) sliding on the solid rod.

d - The centromedullary alignment (Figs 14 and 14a) is constituted by a cylindrical or olive-shaped instrument (26) of the same diameter as the cutters (22 and 28) and carrying in its longitudinal axis a rod guide (27) of a length of about 10 cm which gives the surgeon alignment or centromedullary aim, and in that the cutter (28) of the same diameter as the olive (26) of the second pre-hole (Figs 15 and 9) is located at the end of a hollow rod slidable on the guide rod of the olive (27).

e - The adjustment of a second pre-hole in the anatomical axis of the femur (Fig. 15) consists of a hollow stem slidable on the guide rod of the olive (27).

f - The digging of a cylinder from the axis given by this adjustment over a length approximately equal to the length of the rod P.T.H. removed is constituted by a cutter (32) of the same diameter as the already open sluice, mounted at the end of a rod (33) on which can rotate a cylinder (34) conical end (35) to avoid the stuffing with chips, the same diameter as the cutter (32) and locked longitudinally by a pin (36). In a given embodiment, the length of the cylinder (34) is 13 cm.

g - Verification of the medico-medullary alignment at any time of the intervention (Fig. 14a) by the same instrument.

h - The bore of the duct (Fig. 16) consists of a tool (Fig. 17 and 18) necessary for digging the cylinder (Fig. 16) according to the given axis.

 - - The introduction of the wick guide constituted by a tool representing a hollow cylinder-shaped aiming gun (4) carrying at its upper end a withdrawal means (37) of the same diameter as the already drilled sluice, a preferential length of about 13 cm and an inside diameter sufficient to allow a wick (5) with a diameter of between 4 and 12 mm, preferably 8 mm, to pass through - the introduction of the wick (5) and the drilling of the stopper cement (3) at its center, whatever the position (Varus or Valgus) of the THA original consists of the aiming gun (h) and a wick (5) with straight flutes (39) and that the tip thereof may be multi-angular for example: triangular (38a), quadrangular (38b). The tool is composed of one or more knives. Each of them has one or more upper and lateral bevels forming a cutting angle with respect to the plane perpendicular to the longitudinal axis of the tool (for the upper and parallel to the longitudinal axis to the tool for the side.

 In a preferred embodiment, the tool (Fig. 21) has two knives (40); it also includes a conical body to prevent overheating.

The rest of the cement is removed by burs of increasing diameter carrying at their ends a guide rod 2 whose diameter corresponds to the diameter of the hole left by the wick (5) or by the preceding burs, or determined directly by a pre-operative radio.

FIG. 1 represents the universal instrument for ablation of the rod.

- Figure 2 shows the instrument of Figure 1 in operating mode.

- Figures 3, 4 and 5 represent the lower part of the universal tool.

- Figure 6 shows a longitudinal section of the femur after ablation of the original prosthesis rod and centromedullary targeting with one of the olives (13) set in the middle part of the light.

- Figure 7 shows an upper view of the femur after removal of the stem P.T.H. original.

Figures 8 and 10 show a view of step h described below.

- Figures 11, 12 and 13 represent the tools necessary for this operation.

FIG. 14 represents the alignment or the centromedullary aiming.

FIG. 15 shows the second prehole of step d described below.

Lafigurel6 is a strong ductilizer of step e, g, described below.

FIG. 14a shows the possibility of verifying the alignment or centromedullary aim at all stages of stage f described hereinafter.

FIGS. 17 and 18 show the tool necessary for digging the cylinder over the approximate length of the P.T.H. original.

FIG. 19 represents the tool necessary for the centromedullary alignment surmounted by the sliding cutter for the purpose of digging the second pre-hole.

- Figures 20 and 21 show the aiming gun and its wick.

FIG. 22 represents an example of one of the cutters used for the progressive removal of the oment plug.

FIG. 23 represents an example of a four knife cutter with section planes.

 Other embodiments are possible within the scope and scope of the present invention, in particular by changing the shape of the tools, the arrangement of the drilling means (burs or drill bits or sighting gun), their cutting angle.

In summary, the advantages of the present invention are:
- Respect of the bone integrity.

- Reliability of the process and increased safety for the surgeonL
- Saving time for the surgeon, the anesthesiologist and, therefore, safety for the patient and
better postoperative result, immediate loading possibility, limitation of
anesthetic and post-operative pharma- ceutical products.

invention relates to a device for implementing the
method of recovery of total hip prosthesis (THA) (Fig.2) or C other method of resumption or implantation of prosthesis of
1st intention requiring alignment or centro-medullary aim
consisting of specific instrumentation to perform
successively the operations of ablation of the femoral stem (1) of
PTH, its surgical cement coat or PMMA (2), and the intramedullary cap (3), characterized in that the method consists of a centromedullary alignment or aiming and used it
wicks (Fig. 20 and 21) or strawberries (Fig. 8,12,13,17,18
19, 22, and 23), which move forward in cement only under pressure and
all are guided by sighting cannons (Fig. 11,18, and (4) Fig.

 20), and in that the device for carrying out the method consists of different tools, each of which corresponds to a phase of the operation a-ablation of the original prosthesis (Figures 2.6 and 7).

b - Drilling a first cavity at best in the longitudinal axis of the femur over a length of about 3 cm (Figs 8 and 10).

c - Central and medullary alignment (Figs 14 and 14a).

d - Adjustment of a second pre-hole in the anatomical axis of the femur (Fig. 15).

e - Digging a cylinder from the axis given by this adjustment.

f - Verification of the centromedullary alignment at any time of the procedure (Fig. 14 bis).

g - Reaming the duct to a height of about 12 cm (Fig. 16).

h - Introduction of the wick guide (4).

i - Introduction of the wick (5) and drilling of the cement plug (3) at its center whatever the position (varus or valgus) of the P.T.H. original (Fig. 2, 6).

j - Removing the rest of the cement by gradually increasing the size of the burs (Fig. 22) or by using the burr (41) of the size corresponding to the dimensions given by the preoperative radio.

 The invention also relates to a device for implementing the method, characterized in that tick (Fig 1) used for the ablation of the stem of the original prosthesis is a piece (Fig. 3) carrying at its upper part (B) a gimbal system with several degrees of freedom (14) on which is screwed a rod (15) surmounted by a fixed part (17), on which rod slides a flyweight (16), the whole allowing Extract the hip prosthesis rods (1) respecting the longitudinal axis of the femur.

 The piece (Fig. 3 and 4) is traversed from bottom to top by an opening (7) whose cut is spherical, preferably heart-shaped, the tip is directed rearwardly. The distance between the tip of the heart and the posterior face of the piece is less at the bottom than at the top (Fig. 3) so as to catch the taper of the Morse taper (10).

 Another opening (8) passes through the room perpendicularly to the first. In this hole, is housed a key (9) whose function is to fit on the Morse taper of the prosthesis, to secure the stem of the hip prosthesis with the extractor (Figure 2).

 In order to block all the existing hip prosthesis cones, and in a particular embodiment, we have made several keys of different sizes (Fig. 5) whose opposite upper and lower faces have an angle a defined along the stem of cone to extract, and pulled by a threaded rod (11) from locking the cone to the workpiece by the action of emou (12).

 The invention also relates to a device for implementing the method, characterized in that the tool (FIGS 8, 11, 12 and 13) necessary for drilling the first cavity (FIGS. by an elongated tool (18), one end of which is refined (19) so as to be able to penetrate into the hole (20) left after the ablation of the original prosthesis (FIGS. 6, 7, 9 and 10).

Said end being recessed (21) so as to allow the cutter (22) carried by its rod (23) to penetrate inside the tool (18) (Fig. 12 and 13) so that in neutral position the cutter (22) is retracted into its housing (21). In order to mill about 3 cm into the cement, the stem of it is graduated (24). In a preferred embodiment, the tool (18) carries a handle (25).

 The invention also relates to a device for carrying out the method, characterized in that the tool necessary for alignment or centromedullary aiming (FIG 14) consists of a cylindrical instrument or of a preferred form of an olive (26) of the same diameter as the strawberries (22 and 28) and carrying in its longitudinal axis a guide rod (27) of a length of about 10 cm which gives the surgeon its alignment or its centromedullary aim, and in that the cutter (28) of the same diameter as the olive (26) of the second pre-hole (Figs 15 and 9) is located at the end of a hollow rod slidable on the guide rod of the olive (27).

 The invention also relates to a device, characterized in that it consists of one of the olives (13) of different sizes fixed at the end of a solid rod (27) serving as a guide, driven into the lumen (20) left during the extraction of the femoral component of the total prosthesis of the reed. A cutter (28) is attached to a hollow rod (31) slidable around the solid rod (27).

This device is completed by the use of a sighting gun (34 - Fig. 18) (4 - Fig. 20).

 In a particular embodiment, the size of the olives (13) is increasing from 4 to 20 millimeters in diameter.

 The invention also relates to a device for implementing the method, characterized in that the necessary tool (FIG.17, 18) for digging the cylinder (FIG.16) according to the axis given during the centromedullary alignment (Figs 14 and 14a) and the adjustment of a second pre-hole in the anatomical axis of the femur (Fig. 15) consists of a cutter (32) of the same diameter as the trap already open, mounted at the end of a rod (33) on which can rot a cylinder (34) with conical end (35) to 6ii * .er the stuffing by the chips, the same diameter as the strawberry (32) and locked longitudinally by a pin (36). By way of example, in a given embodiment, the length of the cylinder (34) is 13 cm.

 The invention also relates to a device for implementing the method, characterized in that tick necessary for the operation of the introduction of the drill guide (4) is a sighting gun in the form of a hollow cylinder (4), carrying at its upper end a withdrawal means (37) of the same diameter as the already drilled sluice, of a preferential length of about 13 cm and an inside diameter sufficient to allow a bit (5) of diameter between 4 to pass. and 12 mm, preferably 8 mm.

 The invention also relates to a device for implementing the method, characterized in that the tool (FIG 21) used for the introduction of the wick (5) and the drilling of the cement plug (3) in its center whatever the position (varus or valgus) of the PTH original (FIG 2, 6) is a wick (5) with straight flutes (39) and that the tip thereof may be multi-angular for example: triangular (38a), quadrangular (38b), and in that the tool being composed of one or more knives, each of them has one or more upper and lateral bevels forming a cutting angle with respect to the plane perpendicular to the longitudinal axis of the tool (for the upper) and parallel to the longitudinal axis to the tool (for the lateral ones).

In a preferred embodiment, the tool (Fig. 21) has two knives (40); it also includes a conical body to prevent heating
The invention also relates to a device for carrying out the method, characterized in that the tools necessary for the gradual removal of the thickness of the cement are burs of increasing diameter (41) carrying at their end a guide rod (42). ) whose diameter corresponds to the diameter of the hole left by the wick (5) or the preceding strawberries, or determined directly by a pre-operative radio.

 The invention also relates to a device for carrying out the method, characterized in that the cutters (22, 28, 32, 41 and 43) consist of two to eight knives (42 and 43), preferably four, positioned perpendicularly to each other. with respect to each other (Fig.

12) of which each knife (Fig. 23) comprises two resizable cutting planes, one lateral (44) and one upper (45) forming a cutting angle with respect to the perpendicular plane of the tool axis (for the upper part). ) and parallel to the longitudinal axis of Tool (for the laterals).

 Other advantages of the present invention could be mentioned, but those mentioned above already show enough to demonstrate novelty and interest.

Claims (11)

 1. Set of tools for recovery of total hip prosthesis, characterized in that it comprises:  a) extraction tool of the prosthesis comprising means for gripping an element of the prosthesis;  (b) cement wick or cutter advancing only if pressure is exerted;  c) device for guiding said wicks or strawberries;  d) sighting device for controlling the depth and the orientation of the hole made by said wicks or strawberries.  2. prosthesis extraction tool of the assembly of claim 1, characterized in that said means for gripping a conical end of the prosthesis to be extracted comprise an opening (7, 8) for receiving an end of the prosthesis and means (7 to 12) for blocking this end.  3. Tool according to claim 2, characterized in that the locking means of a conical end of the prosthesis comprise a first opening (7) heart-shaped receiving the conical end of the prosthesis, the distance between the heart tip and an opposite face of the opening being less at a first end than at a second end, so as to catch the taper of the end of the prosthesis, a second opening (8) perpendicular to the opening (7) heart-shaped receives a key having two opposite faces forming an angle and also locking means (12) of the key (9) embedded against the conical end of the prosthesis.  4. Extraction tool of the prosthesis according to claim 2 or 3, characterized in that it comprises a connection with several degrees of freedom, including a universal joint (14) connecting the gripping means of a prosthesis element to a rod (15) terminated at an end opposite to the connecting element (14) by a stop (17) and guiding in translation a flyweight (16) to allow the hip prosthesis rods to be removed ( 1) respecting the longitudinal axis of the femur.  5. Tool of the assembly of claim 1 of wick or milling type, characterized in that it comprises a plurality of knives substantially rectilinear edge, including knives whose edges are parallel and / or perpendicular to the axis of rotation of the cutter.  6. milling cutter according to claim 5, characterized in that it comprises rotary drive means formed by a rod or a tube, in particular a graduated tube.  7. Milling cutter according to claim 6, characterized in that the tube has the same diameter as the wick or the milling cutter, and in that it comprises a frustoconical end (35) on the side of the bit or the milling cutter in order to avoid stuffing with chips.  8. Tool of the assembly of claim 1 for guiding and / or sighting for controlling the depth and orientation of the hole made in the cement by said drill bits or cutters, characterized in that it comprises a tube, preferably terminated by an olive-shaped piece (26) preferably having the same diameter as the locks or the cutters.  9. Tool according to claims 6 and 9, characterized in that the tube (31) of the wick or the cutter (28) is slidably mounted on the tube (27) of the sighting device.  The wick or bit guide tool of the assembly of claim 1, characterized by its elongated shape and a refined end (19) capable of penetrating into a hole (20) left by the removal of the original prosthesis and having a recess (21) for guiding the cutter (22).  11. Tool according to claim 5, 6 or 7, of wick type (5) cement (3) with straight flutes (39) characterized in that it comprises a polygonal base, in particular triangular (38a) or quadriangular ( 38b), and in that it comprises a plurality of knives, each having an upper bevel forming a cutting angle with respect to a plane perpendicular to the longitudinal axis of the tool and / or lateral bevels parallel to the longitudinal axis of the tool.