FR2689751A1 - Positioning and impacting assembly for intramedullary nail - comprises nail gripping arm with assembly of slidably-fitting support and securing components aligning nail with guide in medullary canal - Google Patents

Abstract

A gripping and manipulating arm (1) receives a nail (2) in cooperation with a nail guide assembly positioned in the medullary canal.Complementary securing components (3-4) are mounted on the arm to ensure temporary angular and translational locking of the nail during its insertion into the guide. A bladed shaft (9) is inserted into the nail after it has been impacted into the medullary canal, following withdrawal of the guide and removal of the securing components. ADVANTAGE - Rapid and secure fastening of nail into position, with simple connection of components.

Description

 Apparatus for the Dose of a medullary nail.

 The invention relates more particularly to an apparatus for placing a nail in the medullary canal of the femur or tibia.

In particular, the nail is hollow and can be slightly bent to correspond to the anatomical profile of the bone considered.

 The problem which the invention proposes to solve is to be able to quickly, safely and effectively impact the medullary nail, on a nailing guide previously placed in the bone, to align the fracture. To date, the means used, generally an aiming impactor device, are not satisfactory. Very often fixing the nail on the impactor device is very difficult to achieve.

 In addition, some central medullary nails use a pallet device for distal locking which protrudes from the end of the nail through slots to ensure its anchoring. However, the establishment of the vane rod requires, in most cases, the disassembly of the impactor, so that guidance problems may appear.

 The object of the invention is to remedy these drawbacks in a simple, safe, efficient and rational manner.

The problem which the invention proposes to solve is to achieve the following essential objectives:
- Ensure simple attachment of the aiming and targeting device to the medullary nail.

 - Being able to lock the vane rod without dismantling the sighting impactor.

 - Obtain, thanks to the impactor sight, a locking of the nail proximally in the two anteroposterior and internal external planes, in particular for the tibia.

 To solve this problem, it was designed and developed an apparatus of the type of those comprising a gripping manipulator arm, intended to receive the nail for its impaction in combination with a nailing guide previously disposed in the medullary canal. .

 According to the invention, the apparatus comprises, suitably mounted on a part of the arm, a series of complementary shaped elements, on the one hand, for temporarily ensuring the angular and translational locking of the nail for its introduction on the nailing guide and, on the other hand, the placement of a vane rod in the impacted nail after removal of the nailing guide and some of said elements.

 To solve the problem posed of securing the nail on the device in a simple and effective manner, while allowing the introduction of the vane rod, without being obliged to dismantle the device, the latter comprises - a positioning element capable of being fixed in angular indexing position on a part of the arm, said element having arrangements, cooperating with arrangements complementary to the nail for its angular indexing.

- A locking element slidably engaged in said positioning element while being angularly indexed therein in the abutment position, said locking element having locking means capable of cooperating with the arrangements of the nail.

- A pusher element intended to be slidably engaged in the locking element, after placing the nail in the positioning element, to act on the locking means in order to put them in cooperation with the arrangements of said nail for ensuring its locking in translation1 said pusher element cooperating in abutment with the nailing guide to be automatically withdrawn, as the nail is introduced on said guide.

 To solve the problem posed of ensuring the angular indexing of the nail, the positioning element is constituted by a cylindrical sleeve engaged in sliding in a centering bearing of the arm, the sleeve and the bearing having complementary means of angular indexing .

 The bore of the sleeve has lugs capable of cooperating with the arrangements of the nail, in the form of a constricted opening constituting a bayonet system formed at the end of the nail.

 To solve the problem of ensuring the locking in translation of the nail relative to the device, the locking element is a hollow rod intended to be engaged in the cylindrical sleeve, in the angular indexing position by means of complementary flats that has a part of said rod and said sleeve.

 The locking means of the locking element can be executed according to different embodiments.

 In one embodiment, these elements consist of retractable balls capable of being urged by the pusher element, to be engaged in the bayonet system of the nail.

 In a preferred embodiment, these elements consist of elastically deformable blades formed at the end of the rod and having bosses, said blades being able to be urged by the pusher element, to cause the engagement of said bosses in the system. nail bayonets.

 Another problem which the invention proposes to solve is to maintain the nail in the locked position relative to the device, while allowing the withdrawal of the medullary guide.

 Such a problem is solved in that the pusher element is constituted by a solid rod, intended to be engaged in the bore of the hollow rod to act on the balls, said solid rod being pushed back by the nailing guide, at as the nail is introduced, so that the guide acts on the locking means, to maintain the locking position in translation.

 To resolve the problem posed of placing the vane rod in the medullary nail, without having to dismantle it from the impactor device, the vane rod is engaged in the bore of the socket, after removal of the elements of locking, to be introduced by means of a gripper handle until these pallets overflow into two slots formed at the end of said nail, opposite the end having the bayonet arrangements.

 Another problem which the invention proposes to solve is to modify the angular orientation of the nail in the apparatus, depending on the application envisaged, in particular in the case of an impaction in the medullary canal of the femur or tibia. .

 Such a problem is solved in that a ring is interposed between the centering surface of the arm and the socket, said ring having angular indexing means, cooperating with those of said range and said socket, for shifting by 90 " the angular positioning of the socket and therefore that of the nail.

 In view of the above and the possibilities of angular positioning of the nail in two positions offset by 90, the socket has holes capable of cooperating with a fixing screw engaged in the arm, the holes being spaced and angularly offset, to correspond at the desired angular indexing of the socket.

 To resolve the problem posed of securing the nail thus impacted in the medullary canal of the bone considered, the arm has a bent portion arranged for engagement and positioning of wicks for making holes for engagement of fixing screws cooperating with the nail.

 In an alternative embodiment, the arm receives a central medullary guide.

The invention is set out below in more detail with the aid of the appended drawings, in which:
Figure 1 is a perspective view before assembly of the main components of the device.

 Figure 2 is a partial view in longitudinal section showing the mounting of the sleeve on the centering surface of the gripper arm.

 Figure 3 is a view corresponding to Figure 2, after interposition of the angular indexing ring.

 Figure 4 is a partial longitudinal sectional view showing the mounting of the sleeve locking element.

 Figure 5 is a cross-sectional view taken along line 5.5 of Figure 4.

 Figure 6 is a view corresponding to Figure 4, after mounting the nail at the end of the sleeve in the angular indexing position.

 FIG. 7 is a cross-sectional view taken along line 7.7 of FIG. 6.

 Figure 8 is a sectional view corresponding to Figure 6, after introduction of the pusher element.

 Figure 8a is a view similar to Figure 8, in another embodiment of the locking means.

 Figure 9 is a cross-sectional view taken along line 9.9 of Figure 8, in the translational locking position of the nail.

 Figure 9 bis is a cross-sectional view taken along line 9bis.9bis of Figure 8bis.

 Figure 10 shows the placement of the nail on the nailing guide.

 Figure 11 is a view corresponding to Figure 10, showing the withdrawal of the pusher element by the nailing guide.

 Figure 12 is a view corresponding to Figure 11, after removal of the nailing guide and the locking element.

 Figure 13 shows the placement of the paddle rod.

Figure 14 shows the drilling of the holes for the passage of the fixing screws of the nail
As shown in FIG. 1, the apparatus comprises a manipulator arm (1) intended to receive a central medullary nail (2) with a view to its impaction in the medullary canal (C) of the bone considered.

 In a known manner, the manipulator arm (1) constitutes a grip handle (la), equipped with a handle (las), to be gripped manually by the operator, in optimum anatomical conditions. Similarly, the nail (2) is hollow to receive a vane rod (9) to ensure the impact of the nail, as will be indicated in the following description.

 According to a characteristic underlying the invention, the gripping manipulator arm (1) is arranged to receive a series of complementary elements (3) (4) (5) determined to ensure the angular and translational locking of the nail ( 2). For this purpose, the different elements (3) (4) (5) are determined to each fulfill a specific function.

 The element (3) constitutes a positioning element capable of being fixed in the angular indexing position on a part of the arm (1), being shaped to receive the nail (2). This positioning element (3) consists of a cylindrical sleeve engaged in a centering surface (lob) of the arm (1). As shown in Figure 1, the sleeve (3) and the bearing (lob) have complementary means of angular indexing. For example, these means consist of lugs (1 bi) formed in a diametrically opposite manner projecting beyond the bearing surface (it), to cooperate with notches (3a) formed on a support flange (3b) of the socket (3).

 The bore of the sleeve (3) has an internal bearing (3c) connecting with another internal bearing (3d) of smaller diameter, so as to constitute a shoulder (3e) acting as a stop. This stop (3e) has two diametrically opposite lugs (3e1) to ensure the angular indexing of the nail (2).

 In this regard, one of the ends of the nail (2) has two diametrically opposite throttled openings (2a), constituting a bayonet system. These slots (2a) cooperate, after engagement of the end of the nail (2) in the internal surface (3c), in the abutment position against the shoulder (3e), with the lugs (3e1), thus ensuring the blocking in angular position of the nail (figure 2).

 The sleeve (3) is fixed in the arm (1b), for example by means of a screw (6) engaged in the body (1), at the level (it), to cooperate with a series of holes (3f) or (3g) formed transversely in the thickness of the sleeve.

 Note that a ring (7) can be interposed between the centering surface (lob) and the sleeve (3). This ring (7) has on one side, diametrically opposite lugs (7a) and, on the other side, diametrically opposite notches (7b) intended to cooperate with respectively, the notches (3a) of the sleeve (3) and lugs (1 b1) of the scope (il).

The pins (7a) and the notches (7b) are offset by 90, so that after engagement of the ring (7) on the bearing surface (3h) of the sleeve (3), the latter is angularly offset by 90 "by relative to the gripper arm (1).

 These provisions are important depending on the impact of the medullary nail in the tibia or femur.

 Note that the holes (3g) and (3f) of the sleeve (3), intended to receive the fixing screw (6), are also angularly offset to correspond to the angular indexing of the sleeve, depending on the interposition or not of the ring (7).

 The element (4) constitutes a locking element shaped to be engaged with free sliding, in the internal range (3d) of the sleeve (3). This element (4) is constituted by a hollow rod (4a), engaged, as indicated, in the bearing surface (3d) of the sleeve (3), in the angular indexing position. For this purpose, one of the ends of the rod (4a) has a cylindrical nose (4b) with two diametrically opposed flats (4b1), in order to cooperate with complementary notches (3j) formed at the end of the sleeve (3), in particular at the end of the range (3i).

 The rod (4a) has locking means capable of cooperating under determined conditions, with the arrangements for angular locking of the nail formed by the constricted slots (2a).

 In the embodiment illustrated in particular in FIGS. 8 and 9, the blocking means consist of two balls (8) diametrically opposite and capable of being urged by the element (5), to be engaged in the constricted slots (2a) .

 In the embodiment illustrated in particular in FIGS. 8a and 9a, the blocking means consist of elastically deformable blades (4d) formed at the end of the rod (4a).

The free end of the blades (4d) has bosses (4d1). The blades (4d) are urged by the element (5) to cause the engagement of said bosses in the constricted openings (2a).

 For this purpose, the element (5) constitutes a pusher in the form of a solid rod (5a) intended to be engaged in the bore (4c) of the rod (4). This rod (5a) has the effect of urging the balls (8). in order to cause their separation to put them in the blocking position with the strangled lights (2a) of the nail (2). The end of the rod (5a) has a cylindrical nose (5b) to facilitate gripping of the element (5).

 It is now necessary to analyze the operation of the apparatus, with particular reference to FIGS. 2 to 14, which show the impact of the central medullary nail (2) in the medullary canal of a tibia (T), by example.

 First of all, it is recalled, in a perfectly known manner, that a nailing guide (10) is previously introduced into the bone marrow canal (T) to reduce the fracture.

 As shown in Figure 2, the sleeve (3) is engaged in the centering surface (lob) of the manipulator arm (1). The sleeve (3) is indexed in rotation, taking into account the engagement of the pins (1b1) in the notches (3a) of the support flange (3b). Depending on the desired angular orientation, for the nail (2), the ring (7) may or may not be interposed (Figure 3). The sleeve (3) is fixed in translation by the screw (6), cooperating either with the holes (3f), or with the holes (3g) (Figures 2 and 3).

 The rod (4a) is then engaged in the socket (3), in particular in the bearing surface (3d) (Figure 4). The locking element (4) is angularly indexed in the sleeve (3) by the system of complementary flats and notches (3j) (4b1).

 The operator then takes the nail (2) and engages it at the end of the socket (3), in particular in the internal bearing (3c) up to the stop position with the shoulder (3e). An angular displacement of the nail has the effect of engaging the bayonet system (2a) with the lugs (3e1) (Figures 5 and 6).

 At this stage, the locking means (8) or (4d1) of the locking element are not in engagement with the constricted openings (2a) of the nail (FIG. 7).

 The pusher element (5) is then engaged in the bore (4c) of the rod (4) (Figures 8 and 8bis). The rod (5a) has the effect of spreading the locking means (8) or (4d1) by pushing them concomitantly, in the constricted slots (2a) of the nail (2) (Figures 9 and 9bis).

 At this level, the nail (2) is fixed to the gripping arm (1) while being blocked there, on the one hand, angularly and, on the other hand, in translation.

 The operator can thus introduce by means of the gripping arm (1), the nail (2) on the nailing guide (10) (Figure 10).

 When the nailing guide (10) abuts against the end of the push rod (5a) of the element (5), the latter is automatically pushed back as the nail (2) is introduced. on the guide (10) (figure 11). It therefore appears that the nailing guide (10) replaces the function of the push rod (5a) by maintaining the locking means (8) or (4d1) in the constricted slots (2a) to keep the nail (2) blocked. , on the one hand, angularly and, on the other hand, in translation.

 The nail being thus impacted, the nailing guide (10) and the element (5) are removed (FIG. 12).

 It is then necessary to engage the vane rod (9) in the nail (2). For this purpose, a grip handle (11) is used. In known manner, this handle (11) is intended to be screwed at the end of the rod (9), for example on a threaded seat (9a). The operator introduces the rod (9) into the bore of the medullary nail which remains integral with the manipulator arm (1). When the rod (9) comes into abutment at the distal end of the nail, the pallets (9b) are automatically spaced through slots (2b) formed at the end of the nail (2) (Figure 13). The primary fixing of the nail (2) is thus obtained. The handle (11) is then unscrewed.

 To ensure the fixing of the nail (2) at the proximal level, use is made in a known manner, for example of drills guided in holes which have a bent part (tic) formed at the level of the centering surface (lob) receiving the various elements. (3) (4) (5). For example, this bent part (1c) has two holes (1 cI) (1c2) to correspond to the holes (2c) and (2d) (Figure 14). The holes (here) and (1c2) are consequently arranged on the bent arm (Ic) to correspond to the orientation of the fixing holes (2c) and (2d) of the nail.

 Note that this fixing is carried out in a perfectly known manner, by screws.

 As indicated, the gripping arm (1) can be shaped in particular at the level of its bent part (1c), to receive a central medullary guide.

 The advantages are apparent from the description.

Claims (13)

-1-Apparatus for placing a central medullary nail in particular, comprising a gripping manipulator arm (1), intended to receive the nail (2) for its impaction in combination with a nailing guide (10) beforehand disposed in the medullary canal, characterized in that it comprises, suitably mounted on a part of the arm (1), a series of complementary elements (3) (4) (5) shaped, on the one hand, to ensure temporarily, the angular and translational locking of the nail (2) with a view to its introduction onto the nailing guide (10) and, on the other hand, the positioning of a vane rod (9) in the impacted nail (2) after removal of the nailing guide (10) and of some of said elements (3) (4) (5). -2- Apparatus according to claim 1, characterized in that the series of elements consists of: - a positioning element (3) adapted to be fixed in angular indexing position on a part (lob) of the arm (1 ), said element (3) having arrangements (3e1), cooperating with complementary arrangements (2a) of the nail for its angular indexing. - a locking element (4) slidably engaged in said positioning element (3) by being angularly indexed therein in the stop position, said locking element (4) having locking means (8) or (4d1) capable of cooperate with the arrangements (2a) of the nail (2). The positioning element (3), to act on the locking means (8) in order to put them in cooperation with the arrangements (2a) of said nail (2) to ensure its locking in translation, said pusher element (5) cooperating in abutment with the nailing guide (10) to be automatically withdrawn, as the nail (2) is introduced on said guide (10). - a pusher element (5) intended to be slidably engaged in the locking element (4), after insertion of the nail (2) in -3- Apparatus according to claim 2, characterized in that the positioning element (3) is constituted by a cylindrical sleeve engaged in sliding in a centering surface (1b) of the arm (1), the sleeve (3) and the scope (1b) having complementary means (3a) (1bI) for angular indexing. -4- Apparatus according to claim 3, characterized in that the bore of the sleeve (3) has lugs (3e1) capable of cooperating with the arrangements (2a) of the nail (2), in the form of a throttled light constituting a bayonet system located at the end of the nail (2). -5- Apparatus according to claim 2, characterized in that the locking element (4) is a hollow rod (4a) intended to be engaged in the cylindrical sleeve (3), in angular indexing position by means of flats complementary (4b1) (3j) that has a part of said rod and said bushing. -6- Apparatus according to claim 2, characterized in that the locking means of the locking element (4) consist of retractable balls (8) adapted to be urged by the pusher element (5), to be engaged in the nail bayonet system (2). -7- Apparatus according to claim 2, characterized in that the locking means of the locking element (4) are constituted by elastically deformable blades (4d) formed at the end of the rod (4a) and having bosses ( 4d1), said blades (4d) being able to be urged by the pusher element (5) to cause the engagement of said bosses in the bayonet system of the nail (2). -8- Apparatus according to claim 2, characterized in that the pusher element (5) consists of a solid rod (5a), intended to be engaged in the bore of the hollow rod (4a) to act on the means blocking (8) or (4d1), said solid rod (5a) being pushed back by the nailing guide (10), as the nail (2) is introduced, so that the guide acts on said locking means for maintaining the locking position in translation. -9- Apparatus according to claim 1, characterized in that the vane rod (9) is engaged in the bore of the sleeve (3), after removal of the locking element (4), to be introduced by means a gripper handle until its pallets overflow (9b) in two slots (2b) formed at the end of said nail (2), opposite the end having the bayonet arrangements (2a). -10- Apparatus according to claim 1, characterized in that a ring (7) is interposed between the centering surface (lob) of the arm (1) and the sleeve (3), said ring (7) having means of 'angular indexing (7a) (7b), cooperating with those of the socket, to offset by 90 "the angular positioning of the socket and therefore that of the nail (2). -11- Apparatus according to claim 1, characterized in that the sleeve (3) has holes (3f) (3g) capable of cooperating with a fixing screw (6) engaged in the arm (1), the holes (3f ) (3g) being spaced and angularly offset, to correspond to the desired angular indexing of the sleeve (3). -12- Apparatus according to claim 1, characterized in that the arm (1) has a bent portion (tic) arranged for the engagement and positioning of wicks to make fixing holes for the fixing of the nail (2 ). -13- Apparatus according to claim 1, characterized in that the arm (1) receives a central medullary guide.