Title of Invention

A BONE PLATE AND AN ASSEMBLY

Abstract

A bone plate comprising a top side (1), an underside (2) that shall make contact with the bone, and several holes (4) from the top side (1) to the underside (2) and configured along the longitudinal plate axis (3) and receiving bone screws (11), where (a) the diameter DL of at least one of these holes (4) when measured in the direction of the longitudinal plate axis (3) is larger than the diameter DQ. of this hole when measured perpendicularly to the longitudinal plate axis (3), and (b) at least one of these holes (4) is fitted with an inside thread (5), whereby (c) at least one of the holes (4) defined in feature (a) comprises a concave recess (6) in its portion facing the top side (1) to receive a bone screw (11) having a spherical head (13), characterized in that (d) the inside thread (3) conically tapers in the direction of the bone-plate's underside (2); and (e) the cone angle of the inside thread (5) is between 5 and 20°.

Full Text

FORM 2 THE PATENTS ACT, 1970 [39 OF 1970] & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See Section 10; rule 13] "A BONE PLATE AND AN ASSEMBLY" SYNTHES AG CHUR, of Grabenstrasse 15, CH-7002 Chur, Switzerland, The following specification particularly describes the nature of the invention and the manner in which it is to be performed:- BONE PLATE WITH CONICAL THREAD The invention relates to as bone plate ' affixation system comprising such a bone plate. Basically there are two kinds of osteosyntheses implemented with bone plates. The first kind relates to „rigid osteosynthesis". Rigid osteosynthesis is used when treating fractures of joints, simple shaft fractures (where nailing is impossible), and also osteotomies. Aside anatomic repositioning ability, the bone per se supports the* stability of osteosynthesis, resulting in earlier and more pain-free extremity-stressing. The advantages of stable fracture treatment also are observed where the blood circulation on account of trauma has been substantially reduced. When treating „non-unions" or in the presence of infection, the fracture must be treated in stabilized manner to allow bone healing and to preclude further stimulating the infection by instability in the fracture gap. The second kind relates to ..flexible osteosynthesis". The biggest advantages of flexible (biological) osteosynthesis relate to caring for comminuted fractures in the shaft zone of long bones. The goal relating to these fractures is keeping the bone lengths, and furthermore the bone ends (joints), in their proper mutual positions. In this procedure the fracture zone is not directly affixed or manipulated, and consequently the blood circulation in this zone is not additionally hampered. The bone plates operate similarly to a locking, medullary pin solely anchored in the metaphyses. These two extremes of plate osteosynthesis, they are indeed far apart. Fractures cannot always be assigned to either kind of osteosynthesis, and accordingly the surgeon frequently must compromise because no implant tradeoff is available to him when combining both methods. Such a combination for instance would be called for when a joint fracture can be compressed by means of tightening screws through the bone plate and the full joint part can be connected, by means of an inner affixation of a cone tapering downward toward the underside 2, and accordingly the inside thread 5 also tapers downward toward the bone plate's underside 2 at a cone angle of 10°. Preferably the inside thread 5 is a double thread. As shown in Fig. 3, the inside thread 5 of the hole 4 nearer the plate end runs along the full thickness of the bone plate from the top side 1 to the underside 2. In the preferred embodiment of the invention shown in Figs. 2 and 4, the two bone-plate holes 4 of Fig. 1 are combined . as a result of which the inside thread 5 shall be inside both elongated holes 4. The thread 5 is situated at that end of the elongated hole which is nearer the center of the plate. Furthermore the two elongated holes are the same as in the embodiment of Fig. 1. Measured.at the underside2 and as indicated by the arc of circle 9, the inside thread 5 subtends an arc of 223° and when measured at the top side 1 and as indicated by the arc of circle 10 subtends an arc of 256°. The table below the preferred parameters depending on the diameter of the inside thread 5. thread diameter 3.0 mm 4.0 mm 5.0 mm double thread yes yes yes pitch of thread 0.7 [mm] 0.9 [mm] 1.0 [mm] depth of thread (= 1/2 of outside/inside diameter- differential) 0.2025 [mm] 0.2575 [mm] 0.2810 [mm] angular excursion (at top side) 200° 200° 190° angular excursion (at underside) 260° 240° 250° Shape of the thread Conical Conical Conical Fig. 5 shows an affixation system fitted with a bone plate as shown in Fig. 4, wherein a bone screw 11 comprising an outside thread 12 at the screwhead 13, said outside thread 12 matching the bone-plate's inside thread 5. Appropriately the bone screw 12 is self-drilling and self-tapping. WE CLAIM: 1. A bone plate comprising a top side (1), an underside (2) that shall make contact with the bone, and several holes (4) from the top side (1) to the underside (2) and configured along the longitudinal plate axis (3) and receiving bone screws (11), where (a) the diameter DL of at least one of these holes (4) when measured in the direction of the longitudinal plate axis (3) is larger than the diameter DQ. of this hole when measured perpendicularly to the longitudinal plate axis (3), and (b) at least one of these holes (4) is fitted with an inside thread (5), whereby (c) at least one of the holes (4) defined in feature (a) comprises a concave recess (6) in its portion facing the top side (1) to receive a bone screw (11) having a spherical head (13), characterized in that (d) the inside thread (3) conically tapers in the direction of the bone-plate's underside (2); and (e) the cone angle of the inside thread (5) is between 5 and 20°. 2. The bone plate as claimed in claim 1, wherein the said inside thread (5) subtends an arc of at least 180° of the geometric body formed by it. 3. The bone plate as claimed in either of claims 1 and 2, wherein the said inside thread (5) subtends an arc of 190 to 280° of the geometric body formed by it. 4. The bone plate as claimed in claim 3, wherein the said inside thread (5) subtends an arc at least of 200 to 250° of the geometric body formed by it. 5. The bone plate as claimed in one of claims 1 to 4, wherein when measured at the underside (2) the said inside thread runs across an arc of 180 to 230° and when measured at the top side (1) it runs across an arc of 200 to 270°. 6. The bone plate as claimed in one of claims 1 to 5, wherein the holes (4) defined by the features (a) and (b) are mutually identical whereby the inside thread (5) is fitted inside a hole (4) of which the diameter DL when measured in the direction of the longitudinal plate axis (3) is larger than the diameter D of this hole (4) measured perpendicularly to the longitudinal plate axis (3). 7. The bone plate as claimed in claim 6, wherein when seen in the direction of the longitudinal plate axis (3), the inside thread (5) is situated at one of the two ends of the elongated hole (4) defined in feature (a), preferably nearer the plate's center (8). 8. The bone plate as claimed in one of claims 1 to 7, wherein the concave recess (6) is spherically configured. 9. The bone plate as claimed in one of claims 1 to 8, wherein the said underside (1) is concave. 10. The bone plate as in one of claims 1 to 9, wherein the said inside thread (5) runs through the full thickness of the bone plate from the top side (1) to the underside (2). 11. The bone plate as claimed in one of claims 1 to 11, wherein the said hole (4) flares in its unthreaded sector in its lower portion facing the underside (2). 12. The bone plate as claimed in one of claims 1 to 11, wherein the ratio of DL/D is in the range of 1.01 to 3.00. 13. The bone plate as claimed in claim 12, wherein the said ratio of DL/D is in the range of 1.1 to 1.5. 14. An assembly comprising a bone plate claimed in any one of claims 1 to 13, wherein in addition it comprises at least one bone screw (11) fitted with an outer thread (12) at the screwhead (13), said outer thread (12) matching the inside thread (5). 15. The assembly as claimed in claim 14, wherein the said bone screw (11) is self-drilling. 16. The assembly as claimed in any one of claims 14 and 15, wherein the said bone screw (11) is self-tapping. Dated this 16th day of August, 2001. [RANJNA MEHTA-DUTT] OF REMFRY & SAGAR ATTORNEY FOR THE APPLICANTS

Documents:

abstract1.jpg

in-pct-2001-00986-mum-assingment(13-9-2006).pdf

in-pct-2001-00986-mum-cancelled pages(20-1-2005).pdf

in-pct-2001-00986-mum-claims(granted)-(20-1-2005).doc

in-pct-2001-00986-mum-claims(granted)-(20-1-2005).pdf

in-pct-2001-00986-mum-correspondence(14-11-2006).pdf

in-pct-2001-00986-mum-correspondence(ipo)-(12-10-2006).pdf

in-pct-2001-00986-mum-drawing(20-1-2005).pdf

in-pct-2001-00986-mum-form 19(11-3-2004).pdf

in-pct-2001-00986-mum-form 1a(16-8-2001).pdf

in-pct-2001-00986-mum-form 1a(20-1-2005).pdf

in-pct-2001-00986-mum-form 2(granted)-(20-1-2005).doc

in-pct-2001-00986-mum-form 2(granted)-(20-1-2005).pdf

in-pct-2001-00986-mum-form 3(16-8-2001).pdf

in-pct-2001-00986-mum-form 3(20-1-2005).pdf

in-pct-2001-00986-mum-form 6(11-11-2006).pdf

in-pct-2001-00986-mum-petition under rule 137(20-1-2005).pdf

in-pct-2001-00986-mum-petition under rule 138(20-1-2005).pdf

in-pct-2001-00986-mum-power of authority(10-7-2001).pdf

in-pct-2001-00986-mum-power of authority(2-10-2006).pdf

in-pct-2001-00986-mum-power of authority(20-1-2005).pdf