GB2542350A - Method of creating polyaxial threads and a workpiece with a novel polyaxial thread - Google Patents
Method of creating polyaxial threads and a workpiece with a novel polyaxial thread Download PDFInfo
- Publication number
- GB2542350A GB2542350A GB1516298.5A GB201516298A GB2542350A GB 2542350 A GB2542350 A GB 2542350A GB 201516298 A GB201516298 A GB 201516298A GB 2542350 A GB2542350 A GB 2542350A
- Authority
- GB
- United Kingdom
- Prior art keywords
- polyaxial
- thread
- workpiece
- threads
- creating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 17
- 238000003801 milling Methods 0.000 claims abstract description 6
- 238000010146 3D printing Methods 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/80—Cortical plates, i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates
- A61B17/8052—Cortical plates, i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates immobilised relative to screws by interlocking form of the heads and plate holes, e.g. conical or threaded
- A61B17/8057—Cortical plates, i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates immobilised relative to screws by interlocking form of the heads and plate holes, e.g. conical or threaded the interlocking form comprising a thread
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/80—Cortical plates, i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates
- A61B17/8033—Cortical plates, i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates having indirect contact with screw heads, or having contact with screw heads maintained with the aid of additional components, e.g. nuts, wedges or head covers
- A61B17/8047—Cortical plates, i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates having indirect contact with screw heads, or having contact with screw heads maintained with the aid of additional components, e.g. nuts, wedges or head covers wherein the additional element surrounds the screw head in the plate hole
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/80—Cortical plates, i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/80—Cortical plates, i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates
- A61B17/8061—Cortical plates, i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates specially adapted for particular bones
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61D—VETERINARY INSTRUMENTS, IMPLEMENTS, TOOLS, OR METHODS
- A61D1/00—Surgical instruments for veterinary use
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
- B23G1/00—Thread cutting; Automatic machines specially designed therefor
- B23G1/32—Thread cutting; Automatic machines specially designed therefor by milling
- B23G1/34—Thread cutting; Automatic machines specially designed therefor by milling with a cutting bit moving in a closed path arranged eccentrically with respect to the axis of the rotating workpieces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B39/00—Locking of screws, bolts or nuts
- F16B39/22—Locking of screws, bolts or nuts in which the locking takes place during screwing down or tightening
- F16B39/28—Locking of screws, bolts or nuts in which the locking takes place during screwing down or tightening by special members on, or shape of, the nut or bolt
- F16B39/30—Locking exclusively by special shape of the screw-thread
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
- B23G2210/00—Details of threads produced
- B23G2210/04—Internal threads
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
- B23G2210/00—Details of threads produced
- B23G2210/48—Threads having a special form or profile not otherwise provided for
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B37/00—Nuts or like thread-engaging members
- F16B37/08—Quickly-detachable or mountable nuts, e.g. consisting of two or more parts; Nuts movable along the bolt after tilting the nut
- F16B37/0807—Nuts engaged from the end of the bolt, e.g. axially slidable nuts
- F16B37/085—Nuts engaged from the end of the bolt, e.g. axially slidable nuts with at least one unthreaded portion in both the nut and the bolt
Landscapes
- Health & Medical Sciences (AREA)
- Orthopedic Medicine & Surgery (AREA)
- Life Sciences & Earth Sciences (AREA)
- Surgery (AREA)
- Engineering & Computer Science (AREA)
- Veterinary Medicine (AREA)
- Public Health (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Medical Informatics (AREA)
- Neurology (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Molecular Biology (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Zoology (AREA)
- Wood Science & Technology (AREA)
- Surgical Instruments (AREA)
Abstract
A method of creating polyaxial threads and a work piece with polyaxial threads wherein the polyaxial threads comprise milling a tapered reuleaux triangle threaded aperture 51A, 52A, 53A, 54A, 55A in a work piece. The workpiece will preferably be an osteosynthesis plate or a TPLO plate 50 which will have one or more threaded apertures.
Description
TITLE: Method of Creating Polvaxial Threads and a Workpiece with a Novel Polyaxial Thread
The present invention relates to a method of creating polyaxial threads, and a workpiece with a novel polyaxial thread.
It is known to create poly-axial threads in workpieces such as osteosynthesis or TPLO (Tibial Plateau Levelling Osteotomy) plates. Figure 1 shows part of such an osteosynthesis plate 1 in which holes 10 have polyaxial threads. The method of creating the holes 10 involve a) drilling a round hole in the plate 1, b) milling a thread 11 in the hole wall, and c) machining four radially spaced cut-outs 12A,12B,12C,12D parallel to and radially spaced from the thread axis. The process of creating the cut-outs creates burrs at the ends of the threads which need to be removed by d) re-threading and brushing the holes. This four step process is time consuming leading to; ' ' : additional cost of fabricating such plates 1. It is the cut-outs which allow a threaded head screw to be received at different angles in the polyaxial thread. Also because the thread is not continuous (formed from sections of threads), the thread is structurally weaker. This process can have limitations, as the interrupts in thread form reduce the thread strength and can result in thread stripping if subjected to excessive load after placement or excessive torque during placement. Thread stripping although uncommon will weaken the overall construct. To avoid this occurrence where excessive load after placement is anticipated, it is usual to advise an increase in the plate size to the next range, i.e. 2.7mm to 3.5mm or 3.5mm to 3.5mm broad etc. This is not always ideal for many reasons, one such being wound closure.
The invention seeks to provide an easier method of creating a polyaxial thread, and a workpiece with a novel polyaxial thread.
According to a first aspect of the present invention there is provided a method creating a polyaxial thread comprising milling a tapered Reuleaux triangle threaded aperture in a workpiece.
The invention also relates to a workpiece, such as an osteosynthesis plate or TPLO plate, with one or more threaded apertures made by the above method.
According to a second aspect of the present invention there is provided a workpiece, such as an osteosynthesis plate or TPLO plate, with a polyaxial thread formed by a tapered Reuleaux triangle threaded aperture.
Embodiments of the invention will now be described with reference to the accompanying drawings in which:
Figure 2 A shows a plan view of an osteosynthesis plate with six thread apertures, and
Figure 2B shows cross-section enlarged view of one aperture of Figure 2A with a cross section of a polyaxial screw therein.
Figure 3 shows a plan view of a small and large TPLO (Tibial Plateau Levelling Osteotomy) plate.
Referring to the Figure 2A there is shown an osteosynthesis plate 20 with six tapered threaded apertures 31,32,33,34,35,36 each made by the method of the invention. Plate 20 may be similar to that shown in Figure l.Each thread 31A,32A,33A,34A,35A,36A of the apertures 31,32,33,34,35,36 is a tapered Reuleaux triangle thread. A Reuleaux triangle is a constant width curve based on an equilateral triangle. All points on a side are equidistant from the opposite vertex.
In Figure 2B there is shown a cross-section enlarged view of one aperture of Figure 2A with a cross section of the thread of a tapered polyaxial screw 40 engaged in the tapered Reuleaux thread 31A of aperture 31. As shown the thread of the screw 40 does not engage in the Reuleaux triangle thread of the aperture 31 adjacent the apexes 3 IB of the triangle whereby radially spaced gaps are provided around the screw 40. This allows a threaded head screw to be received at different angles in the polyaxial thread 31 A, with the gaps serving as if cut-outs (as known hitherto) had been provided.
The invention thus allow a polyaxial thread to be produced using a single milling operation so reducing the cost of producing a workpiece, such as an osteosynthesis plate.
In Figure 3 there is shown a plan view of a large and small TPLO (Tibial Plateau Levelling Osteotomy) plate 50,60. Plate 50 has five threaded apertures 51,52,53,54,55 with Reuleux triangle threads 51 A,52A,53A,54A,55A. Plate 60 has five threaded apertures 61,62,63,64,65,66 with tapered Reuleux triangle threads 61A,62A,63A,64A,65A,66A.
It will be seen that the tread formed as a Reuleux triangular thread is a continuous thread, which provides a stronger structure than a thread formed with sections of thread as hitherto known, thus improving the rigidity of the locking surface.
Instead of forming the Reuleux triangular thread in a workpiece by a milling process, it could be formed by any other suitable manufacturing technique, such as 3D printing techniques or using a lathe.The invention thus also relates to a workpiece, such as an osteosynthesis plate or TPLO plate, with a polyaxial thread formed by a tapered Reuleaux triangle threaded aperture.
The invention may take a form different to that specifically described above.
Further modification will be apparent to those skilled in the art without departing form the scope of the present invention.
Claims (7)
1. A method of creating a polyaxial thread comprising milling a tapered Reuleaux triangle threaded aperture in a workpiece.
2. A workpiece with one or more threaded apertures made by the method of claim 1.
3. A workpiece according to claim 2 when in the form of an osteosynthesis plate or TPLO plate.
4. A workpiece with a polyaxial thread formed by a tapered Reuleaux triangle threaded aperture.
5. A workpiece according to claim 4 when in the form of an osteosynthesis plate or TPLO plate.
6. A method of creating a polyaxial thread substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
7. A workpiece substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1516298.5A GB2542350A (en) | 2015-05-15 | 2015-09-15 | Method of creating polyaxial threads and a workpiece with a novel polyaxial thread |
| EP16723445.9A EP3294169A1 (en) | 2015-05-15 | 2016-05-12 | Method of creating polyaxial threads and a workpiece with a novel polyaxial thread |
| PCT/GB2016/000097 WO2016185156A1 (en) | 2015-05-15 | 2016-05-12 | Method of creating polyaxial threads and a workpiece with a novel polyaxial thread |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB1508532.7A GB201508532D0 (en) | 2015-05-15 | 2015-05-15 | Method of creating polyaxial threads |
| GB1516298.5A GB2542350A (en) | 2015-05-15 | 2015-09-15 | Method of creating polyaxial threads and a workpiece with a novel polyaxial thread |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB201516298D0 GB201516298D0 (en) | 2015-10-28 |
| GB2542350A true GB2542350A (en) | 2017-03-22 |
| GB2542350A8 GB2542350A8 (en) | 2017-10-25 |
Family
ID=56015034
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1516298.5A Withdrawn GB2542350A (en) | 2015-05-15 | 2015-09-15 | Method of creating polyaxial threads and a workpiece with a novel polyaxial thread |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP3294169A1 (en) |
| GB (1) | GB2542350A (en) |
| WO (1) | WO2016185156A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11039865B2 (en) | 2018-03-02 | 2021-06-22 | Stryker European Operations Limited | Bone plates and associated screws |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE8519854U1 (en) * | 1985-07-05 | 1986-04-30 | Mecron Medizinische Produkte Gmbh, 1000 Berlin | Self-tightening straight bone plate |
| DE9114118U1 (en) * | 1991-11-13 | 1992-01-02 | Howmedica GmbH, 2314 Schönkirchen | Supports for the human spine |
| US20110264149A1 (en) * | 2010-04-27 | 2011-10-27 | Dana Pappalardo | Bone fixation system including k-wire compression |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BR112012030248A2 (en) * | 2010-06-02 | 2017-01-24 | Synthes Gmbh | bone plate |
| US9404525B2 (en) * | 2013-03-14 | 2016-08-02 | Imds Llc | Polyaxial locking interface |
-
2015
- 2015-09-15 GB GB1516298.5A patent/GB2542350A/en not_active Withdrawn
-
2016
- 2016-05-12 WO PCT/GB2016/000097 patent/WO2016185156A1/en not_active Ceased
- 2016-05-12 EP EP16723445.9A patent/EP3294169A1/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE8519854U1 (en) * | 1985-07-05 | 1986-04-30 | Mecron Medizinische Produkte Gmbh, 1000 Berlin | Self-tightening straight bone plate |
| DE9114118U1 (en) * | 1991-11-13 | 1992-01-02 | Howmedica GmbH, 2314 Schönkirchen | Supports for the human spine |
| US20110264149A1 (en) * | 2010-04-27 | 2011-10-27 | Dana Pappalardo | Bone fixation system including k-wire compression |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11039865B2 (en) | 2018-03-02 | 2021-06-22 | Stryker European Operations Limited | Bone plates and associated screws |
| US12144529B2 (en) | 2018-03-02 | 2024-11-19 | Stryker European Operations Limited | Bone plates and associated screws |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201516298D0 (en) | 2015-10-28 |
| WO2016185156A1 (en) | 2016-11-24 |
| EP3294169A1 (en) | 2018-03-21 |
| GB2542350A8 (en) | 2017-10-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |