FR2721192A1 - Interchangeable orthopaedic scraper handle - Google Patents

Abstract

The handle incorporates a coupling with a male or female component (9,11) engaging with a matching component (12) on the end of the scraper (2), together with a spring-loaded mechanism (16,18,19) for locking the coupling. The spring-loaded mechanism is connected to the coupling by a rod (7) which slides inside a channel (8) in the handle (1) when actuated by a lever (16). The lever turns about a pivot (17) between two positions in which the coupling is engaged and released respectively.

Description

 The present invention relates to an orthopedic rasp handle or rasp holder, that is to say an ancillary device used by orthopedic surgeons to prepare the medullary canal of a long bone, such as a femur or a humerus. , for the installation of a prosthesis rod.

In addition, the subject of the invention is also the assembly formed by the grater handle and the associated grater.

 Up to now, to prepare the medullary canal of a long bone, one-piece rasps have long been used, consisting on the one hand of a manual grip handle and on the other hand of the rasp itself .

The latter is permanently secured to said grip handle, for example by welding the two ends placed in contact.

 Such a solution is extremely expensive because it presupposes the production of a number of handles equal to the number of rasps necessary for a surgeon during an operation. This must indeed have at its disposal and ready for use, therefore previously sterilized, a set of graters of various dimensions and sizes usable according to the nature and quality of the patient's bone; only the surgeon appreciates the value during the operation.

 Although these graters benefit from an absence of mechanical play in the connection of each grater with its handle since the latter is produced by welding, such a solution is not suitable, not only because of the cost represented by all of the handles gripping, but especially because of the size and weight that it represents.

 On the one hand, if each dimension of rasp is definitively linked to a corresponding grip handle, this results in a considerable bulk, as much during the handling of all the orthopedic ancillary equipment by the surgeon's assistants, as during the spreading of this set on tables arranged inside the operating room so that each element is close to the specialized assistant.

On the other hand, this also implies a high load and weight, both for transporting cases of orthopedic equipment and for handling within a clinic or hospital, since this equipment must be sterilized beforehand.

 Since, in addition, this type of manipulation is generally carried out by female personnel, it is easily understandable that solutions of this kind, in addition to the aforementioned bulk, have appreciable disadvantages in the living environment of hospital personnel.

 We have therefore proposed other solutions which consist in separating the grip handle from its grater, so that all of the equipment necessary for the operation contains only one grater handle common to all dimensions. of rasps contained in said set.

 So far, the achievements of handles for interchangeable rasps have not been satisfactory. For example, a rasp holder has recently been produced which is suitable for rasps, the proximal part of which is extended by a grip rod which can be introduced into a corresponding female orifice formed on the end of the grip handle. Means for locking in translation and in rotation of the grip rod then allow the attachment of each grater with the handle.

 This solution, although reducing the weight of the operating material, is not yet satisfactory, firstly because of the presence of the grip neck on the rasp, but also because of the possibilities of mechanical play existing in the connection, which quickly make it unreliable.

 Indeed, the grip neck located in the proximal extension of the rasp, which most of the time is also used as a test rod for the prosthesis, is placed in the operating space of the surgeon. It therefore tends to interfere with the surgeon's natural operating gestures, so it is rather desirable that it can be removed.

 The object of the invention is therefore to propose a grater-holder grip handle which does not have the aforementioned drawbacks, as far as the grater itself is concerned, due to the elimination of the need for a grip neck (also called neck since it allows the provisional installation of a test articulation head), as regards the rasp holder handle proper.

 According to the invention, the handle comprises a connection system provided with a male or female part cooperating with a female or male part of the rasp, as well as elastic means for locking and blocking the two male and female parts. one over the other.

 The invention opens to the surgeon the possibility of adapting to the trial prosthesis constituted by the rasp, the neck-support of the articulation head which suits him according to the specific morphology of the patient. This is made possible by the advantage provided by the constitution of the prosthesis stem in two parts, the attachment of the neck to the stem itself, which can be easily and quickly carried out in situ.

 According to one embodiment of the invention, the locking and locking means comprise a rod-shaped tie rod slidingly mounted in a bore formed in the second part of the handle and opening at both ends of said second part; this tie rod is provided at one end with a hooking element for the rasp while on its opposite end part a manual cocking lever is articulated around a transverse axis between a raised position and tilted on one of the sides in which the rasp is detached from the handle, and a central position folded over said first part in which the rasp can be secured with the handle means are further provided for cooperating with the lever in order to exert traction on the tie rod when the lever tilts from its raised position, the hooking element of the rasp being able to be locked therein by rotation of the tie rod and of the lever around the axis of the tie rod.

 Such a connection mechanism between the handle and the rasp makes it possible, when it is armed, to firmly secure the rasp with the handle and to maintain this connection without failure. The first part of the handle is long enough to be suitable for manual gripping by any type of person, the curvature of the handle between the two parts also making it possible to bypass the fleshy thickness of the patient's thigh. Thus, the surgeon holds the handle with one hand by its first part, and can manually actuate its rasp as he wishes or even impact it with the other hand using a hammer by acting on the free end of the handle.

 Other particularities and advantages will appear during the description which follows, made with reference to the appended drawings which illustrate two embodiments thereof by way of nonlimiting examples.

 Figure 1 is a longitudinal elevational view with cutaway, on a reduced scale, of a first embodiment of the orthopedic handle rasp holder according to the invention.

 Figure 2 is an elevational view in partial section, substantially to scale, of the handle of Figure 1 and the end of an associated rasp.

 FIG. 3 is a partial top view of the rasp holder handle of FIGS. 1 and 2.

 FIG. 4 is a cross-sectional view on an enlarged scale along 3.3 of FIG. 2.

 Figure 5 is an elevational view in partial section of a second embodiment of the orthopedic handle according to the invention.

 The orthopedic handle 1 shown in Figures 1 to 4 is adapted to be removably attached by its end to a rasp 2 partially shown, intended for the preparation of the medullary canal of a bone not shown, such as a femur or a humerus, before placing a prosthesis stem in this channel.

 The handle 1 essentially consists of two roughly rectilinear parts 3 and 4, connected by a curved part 5, and forming between them an obtuse angle A, the rasp 2 can be secured at the end of the second part 4. L obtuse angle A is determined so that the axis of impaction of a hammer (not shown) on the end 6 of the first part 3 always passes through the mean center C of the various rasps 2 capable of being fixed to the end of the second part 4, regardless of the point of impact I1, I2 ... on the end 6, which is advantageously curved for this purpose.

 Thus the impaction of the rasp 2 in the medullary canal is ensured with the best efficiency, as well as the corresponding preparation of the canal.

 The end 6 constitutes a pommel which can advantageously be made, for example, of unhardened steel, while the rest of the handle 1 is made of hardened steel.

The use of non-hardened steel for the knob 6 avoids the projection of shards during hammer impacts, shards which would be produced with a hardened steel.

 The removable male-female connection means between the second part 4 of the tool holder 1 and the rasp 2 comprise, in the example shown, a tie rod 7 which is essentially cylindrical. The tie rod 7 is slidably mounted in a longitudinal bore 8 machined in the second part 4 and opens out freely at the two ends of the latter. At its end facing the rasp 2, the tie rod 7 ends in a cylindrical portion 9 of diameter smaller than that of the rest of the tie rod 7, and which projects partially outside of the part 4. This male terminal part 9 is provided with an element 11 for attaching the rasp 2, constituted in the example represented by a radial bar 11 of the bayonet type.

 The bar 11 is adapted to be able to be inserted into a corresponding housing 12 of the rasp 2 constituting the female part of the connection system between the rasp 2 and the handle 1. The housing 12 has an entry slot 12a and an offset bottom 12b 90 degrees relative to the slot 12a and separated from the latter by a shoulder 33. The bar 11 and the end 9 can therefore be introduced into the slot 11, then rotated 90 degrees in order to place the bar 11 perpendicular to the entry 11 in the bottom 12b which locks the grater 2 on the handle 1.

 The coupling mechanism of the handle 1 and the rasp 2 also comprises elastic means for locking and blocking the female 12 and male (9, 11) parts one on the other. In the assembly described, these means comprise an eccentric 13 disposed in a chamber 14 formed in the end of the part 4 opposite the radial bar 11 and opening on one side into the bore 8.

 The eccentric 13 is articulated around a transverse axis 15 carried by the longitudinal walls of the chamber 14.

The tie rod 7 extends over the major part of the chamber 14, outside the bore 8, and a lever 16 is articulated on the end of the tie rod 7 around a transverse axis 17. The latter crosses a cam 18 constituting the end of the lever 16. An elastic rod or blade 19 is fixed by one of its ends to the eccentric 13, while its free end cooperates with the corresponding face of the cam 18, at the inside the chamber 14, the elastic rod 19 extending parallel to the tie rod 7.

 The cam 18 which is integral with the lever 16 is made so that the forces exerted on the lever 16 are transmitted by said cam to the elastic rod 19 up to a position of maximum elastic tension of the rod 19; Beyond this maximum position, the elastic reaction of the elastic rod 19 takes place and constitutes a non-return means of the lever 16 while maintaining it in the locked position. Thus, this non-return means provides security to the mechanical connection of the rasp with the handle, and makes it possible to maintain this connection without failure during the entire use of the rasp by the surgeon.

 The eccentric 13 is adapted to be able to cooperate with the tie rod 7 in order to make the latter move back in translation in the bore 8 when the eccentric 13 is itself driven in rotation by the tilting of the elastic rod 19. This tilting can itself be caused by lowering the lever 16 from the raised position of the latter, shown in solid lines in Figure 2, which causes the rotation of the cam 18, the elastic rod 19 and the eccentric 13 .

 In the example illustrated, the cooperation between the eccentric 13 and the tie rod 7 is ensured by means of a radial peripheral notch 21 formed on the eccentric 13 and engaged in abutment without play against a projecting flange 22 of the tie rod 7. The radial edge of the notch or notch 21 is turned towards the cam 18, so that if the cam 13 rotates counterclockwise, it drives the flange 22 and consequently the tie rod 7 and the lever 16 in translation by making them move back relative to the rasp 2. Depending on the angle of rotation of the eccentric 13, the rod 19 which is integral with it can travel a determined angle of clearance in the chamber 14, between its position in solid lines and its position 19 in dashed lines.

 Between the flange 22 and the axis 17, a peripheral groove 23 is formed in which the ends 24 of the radial fingers 25 for retaining the tie rod and the lever 16 in translation are engaged. The fingers 25 are housed in bores 26 containing springs 27 for pushing the fingers 25 against the bottom of the groove 23 (FIG. 4).

 The end of part 4 is fitted with a non-rotating centering pin 28 for the grater 2 and fixed to this end by any suitable means such as a pin 29.

Opposite the stud 28 a corresponding cavity 31 is arranged in the end of the rasp 2 in order to receive the stud which, after hooking and locking of the rasp 2 on the end 9 and the bar 11, s' thus opposes any untimely rotation of the rasp. Finally, in a manner known per se, a hole 32 is machined in the first part 3 of the handle 1 in order to be able to receive a transverse axis (not shown) for locating the anteversion.

 The implementation of the orthopedic handle 1 and the associated rasp 2 which have just been described is carried out as follows.

 To assemble the grater 2 to the handle 1, the mechanism 16, 7, 13, 19, 11 is in the disarmed free position, represented in FIG. 2. The operator then switches the lever 16 to one side or from the other from its position shown in Figure 2. The tilting entralne the tie rod 7 in rotation about its axis, so that after rotation of about 90 degrees, the bar 11, which was perpendicular to the inlet 12a, is parallel to it and can be engaged in it. At the same time the stud 28 is introduced into the housing 31. The end 9 is pushed in so that the bar 11 comes to be placed in the bottom 12t of the housing 12. Then the operator raises the lever 16, so that the bar 11 rotates 90 degrees and is locked in its housing 12b.

 Finally, the operator presses the lever 16 in the direction indicated by the arrow in order to tilt it around the axis 17. During this tilting, the cam 18 rotates and in turn drives the rod 19 and the eccentric 13 in tilting around the axis 15. This eccentric allows a reduction in the force to be exerted on the lever 16; its corresponding rotation, indicated by the arrow in FIG. 2, causes the rear tie rod 7 to move slightly (for example 0.7 mm). This retraction of the tie rod 7, at the end of which the lever 16 comes to take its lowered position 16a in which it is in abutment on the intermediate zone 5, causes a corresponding retraction of the bar 11, which therefore comes to be pressed firmly on the shoulder 33 .So, the rasp 2 is firmly pressed against the end of the part 4 of the handle 1, and locked on the latter the tie rod 7 being prevented from continuing its recoil by the retaining fingers 25 pushed by the springs 27 in the groove 23.

 At the end of the lever 16 tilting, the rod 19 is in the lowered position 19a, as is the cam 18.

The contact point 18a between the latter and the rod 19a is placed relative to the tilting axis 17, so that the restoring torque R exerted on the cam 18 by the rod 19a is directed between the axis 17 and the groove 23, and thus tends to maintain the lever 16 in its locking position 16. This self-locking is obtained by means of an appropriate configuration of the cam 18, which in its armed position exerts a pressure on the rod 19a by its tip 18a , and also thanks to the proper positioning of axis 17.

 The assembly of the handle 1 and the grater 2 is then ready for use. According to an advantageous variant, a caster mounted freely in rotation is disposed in the cam 18 of the lever 16 and is placed in contact with the elastic rod 19, to cooperate with the latter and facilitate the locking-unlocking movements by reducing the forces to exercise on the lever 16.

 Of course, to release the rasp 2, it suffices to maneuver the lever 16, in the opposite direction, by elastic raising of the lever 16, after passing from the non-return position of the cam 18, then by tilting the lever 16 around the axis of the tie rod 7, on one side or the other to a position such as 16b (Figure 3). The rasp thus unlocked can be separated from the handle 1 by simple pulling extracting the end 9 and the bar 11 from the housing 12.

 In the embodiment illustrated in Figure 5, the eccentric 34 does not have a notch or peripheral notch, but is partially engaged in a peripheral groove 35 of the tie rod 36. A spring 37 constituted by a flexible and elastic blade is disposed in the chamber 14, its end situated opposite the eccentric 34 being fixed to the bottom of the chamber 14, for example by a screw 38. Its opposite end exerts permanently on the rod 19 and on the eccentric 34 a return torque in the direction which keeps the lever 16 in the high position, disarmed.

 The operation of this second embodiment is similar to that of FIGS. 1 to 4.

 For the preparation of the medullary canal of a femur associated with a right hip, the cocking lever 16 is rocked to the right, while for a left hip, it is rocked to the left, which keeps it off each time contact with the patient's flesh.

 The lever 16 should not be too long to avoid contact with the flesh, but nevertheless have a length sufficient to reduce the effort required to maneuver. Its length is also adapted so that it can be accessed by the operator's thumb, holding the handle in its hand by its first part 3.

 The invention has in particular the following advantages: at the end of the preparation of the medullary canal, a head of suitable length can be adjusted on the end of the rasp, whereas in the prior art, the surgeon finished the preparation with the last rasp and a grip neck not having the desired length to receive the patella and introduce it into the acetabulum for presetting the prosthesis.

 The rasp / rasp holder connection means used are of the male-female type: they therefore meet a surgical need to free the operating space, and they also allow the surgeon excellent manual holding of the ancillary due to the quality of the link obtained.

 In fact, the invention, which ensures excellent joining of the two elements present and very good reliability, not only does not create mechanical play, but moreover avoids any untimely loosening during the use of the instrument, and therefore provides the surgeon with excellent manual hold. This result is obtained thanks to an automatic device for compensating for the wear of the opposing parts for keeping the faces in contact in the presence of the rasp and the grip handle.

 The wear take-up device is essentially constituted by the cooperation of the cam 18 integral with the lever 16 and the elastic blade 19, on which the cam 18 acts during the rotation action exerted on the lever 16.

 The invention is capable of various variants: thus for example any other means of retaining the tie rod 7 equivalent to the fingers 25 and to the groove 35 can be used and any suitable material, other than steel, can be used for making the grater holder. In addition, the female part 12 could be arranged in the end of the tie rod 7, and conversely the combined male part, can be arranged in the end of the rasp 2, from which it then projects.

 The use of the rasp holder for prostheses other than those of the femur and humerus can be considered if necessary.

Claims (12)

 1. Orthopedic rasp-holder handle (1) adapted to support a rasp (2) for preparing the medullary canal of a long bone, for placing a prosthesis, characterized in that it comprises a connection system provided with '' a male (9,11) or female part cooperating with a female (12) or male part of the rasp, as well as elastic means (16,18,11,19) for locking and blocking the two male and female parts one over the other.  2. Handle according to claim 1, characterized in that said means comprise a tie rod (7) slidably mounted in a bore (8) formed in the handle (1), in that this tie rod is provided at a male end with a element (11) for hooking in a female means (12) of the rasp, while on its opposite end part a manual cocking lever (16) is articulated around a transverse axis (17) between a raised position and tilted on one of the sides in which the rasp (2) is detached from the handle, and a central position folded over said first part (3), in which the rasp can be secured with the handle, and that means (13, 19) are provided to cooperate with the lever (16) in order to exert traction on the tie rod when the lever rocks from its raised position, and to lock the male element (9,11) for hooking in the rasp by rotation of the tie rod and the lever around the axis of the tie rod.  3. Handle according to claim 2, characterized in that said means comprise an eccentric (13) placed in a chamber (14) extending the bore (8) towards the lever, articulated on a transverse axis (15) in the vicinity of an elastic rod or blade (19), one end of which is fixed to the eccentric, extending in the chamber parallel to the tie rod (7) and cooperating with a cam (18) formed by the end of the lever, the eccentric being adapted to cooperate with the tie rod in order to make the latter move back in translation in the bore when said eccentric is itself driven in rotation by the tilting of the rod, of the cam and of the lever from the raised position of this latest.  4. Handle according to one of claims 2 and 3 characterized in that the attachment element (11) is of the bayonet type, adapted to be able to be housed in a female means constituted by a corresponding recess (12) of the grater (2) and to lock the latter on the end of the handle (1) by rotation of the tie rod (7) about its axis, this hooking element being for example constituted by a radial bar.  5. Handle according to claim 4, characterized in that a nipple (28) of anti-rotation centering for the rasp (2) is fixed to the end of said second part (4) of the handle (1), and sized to be able be introduced into a housing (12) complementary to the grater.  6. Handle according to one of claims 3 to 5, characterized in that the cam (18) is shaped so that the elastic rod (19) exerts on this cam a couple (R) of self-locking, by tending elastic reaction maintaining the lever (16) in an armed and non-return position, folded over said first part after cocking and retraction of the tie rod (7).  7. Handle according to one of claims 3 to 5 characterized in that the cam (18) is provided with an end wheel mounted free in rotation, to cooperate with the elastic rod (19).  8. Handle according to one of claims 3 to 5, characterized in that the elastic rod (19) cooperates with a flexible and elastic leaf spring (37), the end of which is located opposite the eccentric (34) is fixed to the bottom of the chamber (14), while its opposite end permanently exerts a restoring torque on the rod (19) and the eccentric (34).  9. Handle according to one of claims 3 to 6 characterized in that the eccentric (13) has a peripheral notch (21) radial engaged without play against a projecting flange (22) of the tie rod (7).  10. Handle according to any one of claims 3 to 8, characterized in that it comprises means for retaining the tie rod (7) in translation, for example radial retaining fingers (25) housed in the walls of the chamber (14) and pushed by springs (27) against an annular groove (23) of the tie rod (7).  11. Handle according to any one of the preceding claims, characterized in that the impaction end (6) of said first part (3) is curved in order to constitute a pommel, made for example of unhardened steel, while the rest (4, 5) of the handle (1) is made of hardened steel.  12. An assembly formed by an orthopedic rasp-holder handle (1) according to any one of claims 1 to 10, and by a rasp (2), in which one end of the rasp comprises a female part (12,12a), adapted to receive a male part (9,11) complementary to the handle in order to ensure the connection between the rasp and the handle, or a male part adapted to cooperate with a complementary female part arranged in the end of the handle.