Title of Invention

INTRAMEDULLARY PIN FOR INSERTION INTO THE MEDULLARY SPACE OF A FEMUR

Abstract The invention relates to an intramedullary pin (1) for insertion into the medullary space of a femur through the lateral compacta of the trochanta major. Said pin comprises a proximal pin section, an adjoining distal pin section and bores (2, 3, 4, 5, 6, 7, 8) for bone screws in both pin sections. The proximal pin section comprises at least one bore (3, 4) running obliquely to the longitudinal axis, so that bone screws can be introduced through said bore into the head of the femur, or a screw can be inserted in an antegrade direction through the bore (2). The distal pin section is at least partially vertical and the proximal pin section curves in a lateral-posterior direction.
Full Text FORM 2
THE PATENT ACT 1970 (39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See Section 10, and rule 13)
1. TITLE OF INVENTION
INTRAMEDULLARY PIN FOR INSERTION INTO THE MEDULLARY SPACE OF A FEMUR

APPLICANT(S)
a) Name
b) Nationality
c) Address

SYNTHES GMBH SWISS Company EIMATTSTRASSE 3, CH-4436 OBERDORF, SWITZERLAND

3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

Description
The invention relates to an intramedullary pin for insertion into the medullary space of a femur.
The prior art includes the document US6461360B1. It substantially describes an intramedullary pin for osteosynthesis. Before insertion into a femur, said intramedullary pin has, at its distal end, in the sagittal plane, a curvature which corresponds to the counter-curvature of the femur. Its proximal end substantially describes a continuous curve with constant radius of curvature in the frontal plane.
US6010506 discloses a hybrid pin having different radii, all of which extend in a plane.
WO02089683 discloses the geometry of a pin as a helix. This geometry ensures that the entry point for a pin inserted in an antegrade direction can be displaced laterally from the trochanter tip. On insertion of pin, the pin rotates through about 90°. The rotation of the pin is influenced substantially by its geometry. The inner wall of the medullary space and spongiosa serve here as a guide structure.
With the use of the pure helical geometry, however, there are difficulties which are caused by the varying anatomy of bones. On reaching the end position, the distal locking holes are not in lateral medial alignment. For correction, the pin must be either inserted further or drawn back. However, the pin rotates about its longitudinal axis as a result. This consequently results in an undesired changed height of the locking position. On reaching the end position, the screws thus cannot be introduced centrally through the neck of the femur for locking in the head of the femur. If only the rotation is to be corrected, this in turn on the other hand leads to a displacement of the implant depth of the pin and hence to an undesired change in the height of the locking position. If the proximal pin end is not yet completely in the bone, the pin must be inserted more deeply. However, this results in an
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undesired continuation of the rotational movement. As a result of this, the optimum positions of the locking options once again change.
It would be desirable for the distal locking holes preferably to be parallel to the frontal plane or in lateral/medial alignment when the pin comes to rest in its final implantation depth range. The pin can then be fixed in the proximal region by means of screws which are inserted through the neck of the femur into the head of the femur. For this locking, the implantation depth of the pin must ensure that the screws can be passed centrally through the neck of the femur. The neck of the femur and head are, however, rotated relative to the frontal plane about the longitudinal axis of the femur. This rotation is described as the anteversion angle. This means that the pin must be adapted to the anatomically changing anteversion angles by rotation of the pin about its longitudinal axis. This is intended to ensure that the screws can be placed centrally through the neck of the femur and centrally in the head. Furthermore, the proximal pin end should be flush with the surrounding cortex or deeper. This is intended to prevent the surrounding tissue from being irritated by the proximal pin end.
It is therefore the object to provide a pin which need not have an adapted geometry for every femur bone exhibiting different growth, in order to fulfil the abovementioned conditions.
The inventor achieves the object by modification of the ends of the helical shape. Here, the proximal end of the pin is curved in a plane. The distal end remains straight. This ensures that, on reaching its final implantation depth range, the pin ceases to rotate by itself. In the final implantation depth range, the pin can be displaced along its longitudinal axis without change of rotation. The pin can nevertheless be arbitrarily rotated about its longitudinal axis without changing its implantation depth.
While the distal pin section therefore has, at least partly, no curvature at all, the
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proximal pin section runs in the lateral posterior direction when it is inserted into the medullary space through the lateral compacta of a trochanter major.
By changing the ends of the helical shape, it is possible to produce an implant which functions optimally for a certain group of bones. The variation in the anatomy no longer has any effect on the functionality of the implant. The implant can be optimally oriented for locking in the bone.
The pin according to the invention preferably has, in the proximal region, two bores running obliquely to the longitudinal axis and parallel to one another and a third bore intersecting the first two bores. The peculiarity of this locking lies in the combination of the possibilities for locking. In the pin according to the invention, the antegrade locking acquires particular importance. The new lateral opening for the pin almost coincides with the insertion direction of the antegrade screw. If only one screw is set proximally, no further skin incision is therefore necessary.
The pin according to the invention preferably has two bores running transversely and parallel to one another and, at the distal end, a bore which is arranged in between, is rotated about the longitudinal axis relative to the plane defined by the two bores and likewise runs transversely. The middle locking screw is arranged rotated through 25° relative to the left and right locking screw.
The peculiarity of the distal locking lies in the combination of the possibilities for locking. In addition to the generally known standard locking, a third bore is present between the two standard bores. By locking the pin with 3 screws, axial stability is achieved. This means that the position of the distal pin end is fixed. The pin cannot be displaced on the screws. The 25° angle of the axial blocking screw prevents the screw from injuring important soft tissues during insertion. This could occur, for example, if the screw is inserted in the sagittal direction (90°). The locking screws are present at a distance of about 30 mm away from one another.
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For introduction of the implant, the pin is connected to a target bow. This usually rests flat on the end of the pin. It results in a continuous transition and contour matching between pin and target bow.
For proper implantation, it is very important to be able to recognise the end of the pin clearly with the aid of an imaging method (X-rays). This is not possible or possible only to an insufficient extent according to the prior art to date. Incorrect insertion depth might have the following consequences: if the pin does not come to rest sufficiently deeply in the bone, the projecting pin end may result in complications such as pain, necrosis, etc. If the pin is implanted too deeply, the result may be offset of the proximal pin end. Furthermore, in growth of bone may occur so that the upper part of the original insertion channel is closed. These possibilities complicate the subsequent explantation of the implant. Moreover, there is the danger that the tip of the pin will penetrate into the knee.
A bevel which interrupts the transition and the contour matching between target bow and pin is preferably formed laterally at the proximal end of the pin according to the invention. In the case of an anterior-posterior X-ray photograph, the end of the pin is as a result easily and clearly detectable. This simplifies the surgery and leads to safer use and a shorter operation time. The pin entry point is on the lateral surface of the trochanter major. This surface can be palpated particularly in slim patients. This means that the surface is covered only by a thin layer of skin. Through the lateral entry point of the pin, it is necessary to prevent the soft tissue from being irritated by the proximal pin end. The advantage of the bevel is that the bevel also ensures that the proximal pin end fits the lateral cortex wall with a matching contour. This prevents irritation of the soft tissue.
A groove by means of which the rotation of the pin on the target bow is fixed is preferably present on the medial side of the proximal end. In comparison, the prior art comprises rotational fixing via two grooves, which however result in a higher manufacturing cost.
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A cylindrical recess into which the diametrically opposite shaft of the connecting screw can penetrate between target bow and pin is present at the proximal end. Consequently, the pin axis is aligned coaxially with the target bow, the thread exerting only the contact pressure. In comparison, the prior art comprises the coaxial alignment directly and only by the thread of the connecting screw.
A particular development provides a special formation of the tip so that this can be tapped without rotation into the spongiosa in the distal femur region in order to be secured there to prevent rotation even without locking by means of a screw. The tip of the pin has, in a radial section, differing from the circular shape, special tip surfaces, in particular concave notches or planar surfaces. In this variant, however, subsequent, arbitrary or involuntary rotation is not possible.
Further developments of the invention are given in the figures and in the dependent patent claims.
These and the list of reference numerals are part of the disclosure.
The invention is explained -in more detail schematically and by way of example with reference to figures.
The figures are described in relation to one another and as a whole.
Fig. 1 shows the pin according to the invention viewed in the anterior to
posterior direction, i.e. in the lateral-medial plane,
Fig. 2 shows the pin according to the invention viewed in the lateral to
medial direction, i.e. in the anterior-posterior plane,
Fig. 3 shows the pin according to the invention viewed in the proximal to
distal direction,
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Fig. 4a shows a particular embodiment of the tip of the pin according to the
invention, viewed in the lateral to medial direction,
Fig. 4b shows a particular embodiment of the tip of the pin according to the
invention, viewed in the distal to proximal direction,
Fig. 5a shows a particular embodiment of the tip of the pin according to the
invention, viewed in the lateral to medial direction,
Fig. 5b shows a particular embodiment of the tip of the pin according to the
invention, viewed in the distal to proximal direction,
Fig. 6a shows a particular embodiment of the tip of the pin according to the
invention, viewed in the lateral to medial direction,
Fig. 6b shows a particular embodiment of the tip of the pin according to the
invention, viewed in the distal to proximal direction and
Fig. 7 shows the proximal end of the tip according to the invention, viewed
in the proximal to distal direction.
Fig. 1-3 show the pin 1 according to the invention in three views. The proximal and distal end planes are rotated 60°-110o, preferably 70°-90° and in particular 80° relative to one another. In this working example, the radius is 300-1300 mm, preferably 900-1200 mm and in particular about 1100 mm. The length of the proximal radius corresponds to the lateral contact surface with the cortex. It is 300-1000 mm, preferably 600-800 mm and in particular 700 mm.
The length of the distal straight section corresponds to the depth to which the distal pin end penetrates into the distal spongiosa structure. It is 35-70 mm, preferably 40-60 mm and in particular about 52 mm.
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The pin 1 is designed with a 120° antegrade bore 2 for a 3.9-6.0 mm thick locking screw, a cranial 130° recon bore 3 for an approx. 6.5 mm thick headless screw which coincides medially with a 120° antegrade bore 2 for a 3.9-6.0 mm thick locking screw, a caudal approx. 130° recon bore 4 for an approx. 6.5 mm thick headless screw and an oval bore 5 for static and dynamic positioning of a 3.9-6.0 mm thick locking screw in the proximal region. Furthermore, a lateral bevel 9 is recognizable at the proximal end.
Finally, two bores 6 and 7 running transversely and parallel to one another and an anterolateral bore 8 which is rotated through 25° relative to the parallel bores 6 and 7 are shown at the distal end. The angle is preferably between 45° and 10° (0°corresponds to the frontal plane or the plane of the two standard locking screws).
Fig. 4a and 4b show a variant of the tip of the pin 1 according to the invention in two views. It has, in a radial section, differing from the circular shape, special tip surfaces 13, in particular three planar surfaces, which have a length of 10-40 mm, preferably 15-25 mm and in particular 20 mm. The total length of the tip is 20-50 mm, preferably 25-35 mm and in particular 30 mm. In addition, the bore 7 is shown.
Fig. 5a and 5b show a variant of the tip of the pin 1 according to the invention in two views. It has, in a radial section, differing from the circular shape, special tip surfaces 13, in particular three concave notches, which have a length of 10-40 mm, preferably 15-25 mm and in particular 20 mm, and a radius of 4-10 mm, preferably 5-8 mm and in particular 6 mm. The total length of the tip is 20-50 mm, preferably 25-35 mm and in particular 30 mm. In addition, the bore 7 is shown.
Fig. 6a and 6b show a variant of the tip of the pin 1 according to the invention in two views. It has, in a radial section, differing from the circular shape, special tip surfaces 13, in particular four concave notches, which have a length of 10-40 mm, preferably 15-25 mm and in particular about 20 mm, and a radius of 4-10 mm, preferably 5-8 mm and in particular about 6 mm. The total length of the tip is 20-50
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mm, preferably 25-35 mm and in particular about 30 mm. In addition, the bore 7 is shown.
Fig. 7 shows the proximal end of the pin 1 according to the invention, viewed from the proximal to distal direction. A lateral bevel 9 which has an angle at the lateral-proximal end relative to the axial pin axis of 10° to 60°, preferably about 40°, is shown. Finally, a cylindrical recess 12 having a thread 11, and a positioning groove 10 on the medial side of the proximal end, are shown.
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List of reference numerals

1 Intramedullary pin
2 Antegrade bore
3 Cranial bore
4 Caudal bore
5 Oval bore
6 Bore parallel to 7
7 Bore parallel to 6
8 Anterolateral bore
9 Lateral bevel
10 Positioning groove
11 Thread
12 Cylindrical recess
13 Tip surface

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WE CLAIM:
1. Intramedullary pin (1) for insertion into the medullary space of a femur through the lateral compacta of the trochanter major, comprising a proximal pin section and an adjoining distal pin section and comprising bores (2,3,4, 5, 6,7,8) for bone screws in both pin sections, the proximal pin section having at least one bore (3, 4) running obliquely to the longitudinal axis, so that bone screws can be inserted through said bore into the head of the femur, characterized in that the distal pin section is at least partly straight and in that the proximal pin section has a curvature in the lateral-posterior direction.
2. Intramedullary pin (1) according to Claim 1, characterized in that a bone screw can be inserted through an antegrade bore (2) instead of through one of the oblique bores (3,4).
3. Intramedullary pin (1) according- to either of the preceding Claims, characterized in that the proximal and distal end planes are rotated 60°-110°, preferably 70°-90° and in particular about 80° relative to one another and the radius of the pin is 300-1300 mm, preferably 900-1200 mm and in particular about 1100 mm.
4. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the length of the proximal pin section corresponds to the lateral contact surface with the cortex, and in that the proximal pin section has a radius of 300-1000 mm, preferably 600-800 mm and in particular about 700 mm.
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5. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the length of the distal straight section corresponds to the depth at which the distal pin end in the implanted state penetrates into the distal spongiosa structure and is 35-70 mm, preferably 40-60 mm and in particular about 52 mm.
6. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the pin is formed in such a way that, on reaching its final implantation depth range, it ceases to rotate by itself and, in the final implantation depth range, can be displaced along its longitudinal axis without changing the rotation, and in that the pin can be rotated arbitrarily about its longitudinal axis in the final implantation depth range without changing its implantation depth.
7. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the pin has the following bores:
- a 120° antegrade bore (2) for an approx. 5.0 mm thick locking screw
- a cranial 130° recon bore (3) for an approx. 6.5 mm thick headless screw
which coincides medially with the antegrade bore (2),
- a caudal 130° recon bore (4) for a 3.9-6.0 mm thick headless screw,
- an oval bore (5) for static and dynamic positioning of a 3.9-6.0 mm thick
locking screw in the proximal region
- and two bores (6) and (7) running transversely and parallel to one another
and, at the distal end, an anterolateral bore (8) rotated through 25°
relative to said bores (6, 7).
8. Intramedullary pin (1) according to any of the preceding Claims,
characterized in that exclusively the proximal pin section has an oval bore (5).
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9. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the pin has, at its proximal end, a lateral bevel (9) which has an angle of 10° to 60°C, preferably about 40° to the axial pin axis at the lateral-proximal end.
10. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the transition and contour matching between the proximal end of the pin and a target bow which can be caused to engage the pin is interrupted.
11. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the pin has a single positioning groove (10) at its proximal end.
12. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the pin has, at its proximal end, a cylindrical recess (12) with a thread (11).
13. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the pin axis through the cylindrical recess (12) can be aligned coaxially with a target bow, and the thread (11) exerts only the contact pressure.
14. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the total length of the pin tip is 20-50 mm, preferably 25-35 mm and in particular about 30 mm, and in that this has, in a radial section, differing from the circular shape, special tip surfaces (13) in particular at least three concave notches, the length of which is 10-40 mm, preferably 15-25 mm and in particular about 20 mm and the radius of which is 4-10 mm, preferably 5-8 mm and in particular about 6 mm.
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15. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the total length of the pin tip is 20-50 mm, preferably 25-35 mm and in particular about 30 mm, and in that this has, in a radial section, differing from the circular shape, special tip surfaces (13), in particular at least three planar surfaces, the length of which is 10-40 mm, preferably 15-25 mm and in particular about 20 mm.
16. Intramedullary pin (1) according to any of the preceding Claims, characterized in that the tip of the pin is formed in such a way that it can be tapped without rotation into the spongiosa in the distal femur region in order to be secured there to prevent rotation even without locking by means of a screw.
Dated this 2nd day of April, 2007

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Abstract
The invention relates to an intramedullary pin (1) for insertion into the medullary space of the femur through the lateral compacta of the trochanter major, comprising a proximal pin section and an adjoining distal pin section and comprising bores (2,3, 4, 5, 6, 7, 8) for bone screws in both pin sections, the proximal pin section having at least one bore (3, 4) running obliquely to the longitudinal axis, so that bone screws can be inserted through said bore into the head of the femur, or a screw can be inserted in the antegrade direction through the bore (2), the distal pin section being at least partly straight and the proximal pin section having a curvature in the lateral-posterior direction.
To,
The Controller of Patents,
The Patent Office,
15
Mumbai


Documents:

479-mumnp-2007-abstract(2-4-2007).pdf

479-mumnp-2007-abstract(29-5-2009).pdf

479-mumnp-2007-abstract(amanded)-(29-7-2009).pdf

479-mumnp-2007-abstract(granted)-(21-3-2011).pdf

479-mumnp-2007-abstract.doc

479-mumnp-2007-abstract.pdf

479-MUMNP-2007-CANCELLED PAGE(29-7-2009).pdf

479-mumnp-2007-cancelled pages(29-7-2009).pdf

479-mumnp-2007-claims(2-4-2007).pdf

479-mumnp-2007-claims(29-5-2009).pdf

479-MUMNP-2007-CLAIMS(29-7-2009).pdf

479-mumnp-2007-claims(amanded)-(29-7-2009).pdf

479-MUMNP-2007-CLAIMS(AMENDED)-(22-2-2011).pdf

479-mumnp-2007-claims(granted)-(21-3-2011).pdf

479-mumnp-2007-claims.doc

479-mumnp-2007-claims.pdf

479-MUMNP-2007-CORRESPONDENCE(17-2-2011).pdf

479-MUMNP-2007-CORRESPONDENCE(22-2-2011).pdf

479-mumnp-2007-correspondence(29-5-2009).pdf

479-MUMNP-2007-CORRESPONDENCE(29-7-2009).pdf

479-mumnp-2007-correspondence(ipo)-(23-3-2011).pdf

479-mumnp-2007-correspondence(ipo)-(9-7-2009).pdf

479-mumnp-2007-correspondence-received.pdf

479-mumnp-2007-descripiton (complete).pdf

479-mumnp-2007-description(complete)-(2-4-2007).pdf

479-mumnp-2007-description(complete)-(29-5-2009).pdf

479-mumnp-2007-description(granted)-(21-3-2011).pdf

479-mumnp-2007-drawing(2-4-2007).pdf

479-mumnp-2007-drawing(29-5-2009).pdf

479-mumnp-2007-drawing(granted)-(21-3-2011).pdf

479-mumnp-2007-drawings.pdf

479-MUMNP-2007-ENCLOUSER(29-7-2009).pdf

479-MUMNP-2007-ENGLISH TRANSLATION(22-2-2011).pdf

479-mumnp-2007-form 1(2-4-2007).pdf

479-mumnp-2007-form 1(25-5-2007).pdf

479-mumnp-2007-form 1(29-5-2009).pdf

479-mumnp-2007-form 18(2-4-2007).pdf

479-mumnp-2007-form 2(29-5-2009).pdf

479-mumnp-2007-form 2(complete)-(2-4-2007).pdf

479-mumnp-2007-form 2(granted)-(21-3-2011).pdf

479-mumnp-2007-form 2(title page)-(2-4-2007).pdf

479-mumnp-2007-form 2(title page)-(29-5-2009).pdf

479-mumnp-2007-form 2(title page)-(granted)-(21-3-2011).pdf

479-MUMNP-2007-FORM 26(22-2-2011).pdf

479-MUMNP-2007-FORM 3(17-2-2011).pdf

479-mumnp-2007-form 3(29-5-2009).pdf

479-mumnp-2007-form 5(2-4-2007).pdf

479-mumnp-2007-form 5(29-5-2009).pdf

479-mumnp-2007-form-1.pdf

479-mumnp-2007-form-2.doc

479-mumnp-2007-form-2.pdf

479-mumnp-2007-form-26.pdf

479-mumnp-2007-form-3.pdf

479-mumnp-2007-form-5.pdf

479-mumnp-2007-form-pct-ib-306.pdf

479-mumnp-2007-pct-search report.pdf

479-MUMNP-2007-PETITION UNDER RULE 137(17-2-2011).pdf

479-MUMNP-2007-REPLY TO HEARING(22-2-2011).pdf

479-mumnp-2007-wo international publication report(29-5-2009).pdf

abstract1.jpg


Patent Number 246904
Indian Patent Application Number 479/MUMNP/2007
PG Journal Number 12/2011
Publication Date 25-Mar-2011
Grant Date 21-Mar-2011
Date of Filing 02-Apr-2007
Name of Patentee SYNTHES GMBH
Applicant Address EIMATTSTRASSE 3, CH - 4436 OBERDORF
Inventors:
# Inventor's Name Inventor's Address
1 KAUP THOMAS BIREGGSTRASSE 16, CH-6003 LUZERN
PCT International Classification Number A61B17/72
PCT International Application Number PCT/IB2004/003425
PCT International Filing date 2004-10-20
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/522,568 2004-10-14 U.S.A.