WO1999042053A1 - Hip compression screw assemblies and joints therefor - Google Patents
Hip compression screw assemblies and joints therefor Download PDFInfo
- Publication number
- WO1999042053A1 WO1999042053A1 PCT/GB1999/000545 GB9900545W WO9942053A1 WO 1999042053 A1 WO1999042053 A1 WO 1999042053A1 GB 9900545 W GB9900545 W GB 9900545W WO 9942053 A1 WO9942053 A1 WO 9942053A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- joint according
- setting
- setting member
- block
- screw
- Prior art date
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- 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, setting implements or the like
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/74—Devices for the head or neck or trochanter of the femur
- A61B17/742—Devices for the head or neck or trochanter of the femur having one or more longitudinal elements oriented along or parallel to the axis of the neck
- A61B17/748—Devices for the head or neck or trochanter of the femur having one or more longitudinal elements oriented along or parallel to the axis of the neck with means for adapting the angle between the longitudinal elements and the shaft axis of the femur
Definitions
- This invention relates to two-dimensional joints and their use in compression screw assemblies, particularly for use in surgical operations and in the treatment of proximal femur fracture.
- the typical orthopaedic surgical process is to secure the fractured bone using a compression screw consisting of a lag screw and an angle plate secured thereto at a fixed angle.
- Such screws are available with different angles between the lag screw and plate, typically increasing at 5° intervals from 120° to 150°.
- the angle plates are coupled to the lag screw by a system which allows axial movement of the plate relative to the screw. Because the location of the lag screw in the treatment of a fracture of this kind is critical, the limitation on the angular relationship between the lag screw and the angle plate means that it is difficult in almost every case to fit the compression screw at the ideal position.
- That Application discloses an adjustable two-dimensional joint for use in compression screw assemblies, which allows for relative alignment of the angle plate of such an assembly with the lag screw, even when these components are effectively fitted to the respective bone sections.
- That joint adjustable in two dimensions, comprises first and second elements formed with complementary male and female cylindrical surfaces defining the plane of adjustment, the first element defining a hinge point at the axis of the male cylindrical surface, and the second element including a fulcrum extending to the axis of the female cylindrical surface.
- a setting device extends between pivot points on the first and second elements which is adjustable in length between the pivot points to alter the angle 2 between the elements.
- the first element will constitute or be effectively part of the angle plate and the second element constitute or be part of the lag screw.
- the present invention seeks to improve on the joint disclosed in my International Application referred to above, and particularly to simplify its assembly. This is primarily achieved by modifying the geometry of the joint such that adjustment of the setting device is substantially linear. This enables the joint to be set by means of a relatively simple linear coupling, such as a screw thread.
- a joint according to the present invention as in my previous design, comprises first and second elongate elements formed with complementary male and female cylindrical surfaces defining the plane of adjustment in two dimensions.
- the setting member extends from a pivot point on the first element into the second element along a set axis inclined to the axis of the second element, and it is adjustably coupled to the second element to alter the angle between the elements when the cylindrical surfaces are in sliding engagement.
- the adjustable coupling will typically comprise complementary male and female screw threads, with the male thread normally being formed on the setting member.
- the coupling between the setting member and the second element can be deliberately designed to provide a degree of freedom accommodating some lateral shift of the pivot point on the first element relative to the set axis during adjustment of the coupling. This can be accomplished by providing for some translational movement of the point on the first element, or permitting some pivotal movement between the setting member and the set axis during adjustment of the coupling. Generally, the latter is preferred as it provides more positive locking of the first element in the joint, and it can be accomplished by establishing no 3 more than a loose fit between screw threads on the setting member and the second element.
- some form of mechanism will usually be provided for locking the elements at an angle set by the setting member.
- a simple such mechanism comprises a pin or screw which engages the setting member to prevent it pivoting away from the locked position.
- a preferred mechanism exploits the optional use of a block mounted in the second element to which the second member is adjustably coupled.
- Such a block can be adjustably mounted in the second element, preferably for selective axial movement parallel to the set axis.
- a locking mechanism can thus comprise engagement of the exposed end of such a block with a projection or other part of the first element; before, during or after setting of the angle between the elements.
- the block can be mounted in the second element by means of a screw thread assembly, and if a similar mechanism is employed for coupling the second member to the block, then by using oppositely sensed threads adjustment of the elements and the locking of such adjustment can be accomplished substantially simultaneously.
- Figure 1 shows in cross-section a two-dimensional joint according to the invention for use in a hip compression screw assembly; and Figure 2 shows a view similar to that of Figure 1, but illustrating the use of an alternative form of setting member.
- the joint shown in Figure 1 has first and second elements 2, 4 which are pivotal relative to each other around an axis 6. Such pivotal movement is constrained to be in a single two-dimensional plane by complementary male (10) and female (12) cylindrical surfaces 4 respectively on the elements 2 and 4.
- the pivot axis 6 is located at the axis of the male cylindrical surface 10 on the first element 2, which coincides with the axis of the female surface 12, when the cylindrical surfaces 10, 12 are in sliding engagement with each other.
- the female cylindrical surface 12 is formed on an enlarged peripheral segment 14 of the second element 4 which, in a hip screw assembly, would constitute the lag screw secured to or to be secured in the caput of a femur in the treatment of a typical proximal femur fracture.
- a block 16 mounted for translational movement along a set axis 18, inclined to the axis itself of the element 4.
- the block 16 is typically cylindrical, and mounted on the second element 4 by means of a screw thread.
- a setting member 20 is coupled to the block 16 for axial movement relative thereto substantially along the set axis 18.
- the setting member 20 comprises a ball 22 and shaft 24, the shaft 24 bearing a male screw thread received in a complementary female thread within the block 16.
- the ball 22 is mounted in a suitable recess in the first element 2, and the geometry of the joint is such that rotation of the ball 22 and therefore the shaft 24 to cause axial movement of the setting member 20 relative to the block 16 and therefore the second element 4, adjusts the angle between the elements 2 and 4 while maintaining the complementary cylindrical surfaces 10 and 12 in sliding engagement.
- This geometry requires the coupling between the setting member 20 and the block 16 and/or the second element 4 to accommodate some lateral movement of the ball 22 relative to the set axis 18, and in the illustrated embodiment this is accomplished by the adoption of a slightly loose threaded coupling between the member 20 and the block 16 and/or the block 16 and the body of the second element 4. This permits some pivotal movement of the member 20 5 in the second element 4.
- the complementary socket 26 in the first element 1 which receives the ball 22 may be enlarged in a direction substantially perpendicular to the set axis but of course in the plane of the angular adjustment of the joint .
- the arrangement described above sets the angle of the joint described against turning in one sense.
- the joint can still be turned in the other sense by separation of the complementary cylindrical surfaces 10 and 12 and/or withdrawal of the ball 22 from its seat 26.
- a locking mechanism is employed which effectively prevents such pivotal movement of the shaft 24 relative to the ball seat 26.
- a locking screw or pin can be used to achieve this end, or a simple wedge.
- a preferred mechanism exploits the use of the block 16 as the means for receiving the shaft 24 of the setting member 20.
- the block 16 is adjustably mounted in the second element 4 and as shown can be withdrawn from the element to engage a projection 28 at the proximal end of the first element 2.
- the block 16 is normally mounted in the element 4 by means of a conventional screw thread, which particularly facilitates this locking adjustment. It is further facilitated if the thread coupling the shaft 24 to the block 16 is of the opposite hand relative to that of the thread coupling the block 16 to the second element 4. With this arrangement the exercise of adjusting and tightening the setting member 20 can simultaneously draw the block 16 up and into locking engagement with the projection 28 on the first element 2.
- the setting member 20 comprises a main body consisting of two threaded portions 30,32.
- One threaded portion 32 defines the adjustable coupling to the second element 4 in a manner similar to that described above with reference to Figure 1.
- the other portion 30 has mounted 6 thereon a ball unit 34 with a complementary female thread, enabling the position of the ball 34 relative to the setting member 20 itself to be adjusted.
- This adjustment can be effected by a tool 36 adapted to engage appropriate elements such as castellations 38 on the exposed end of the ball unit 34.
- the preferred ball unit is in the form of a sleeve whereby the end of the setting member 20 is accessible therethrough, enabling the coupling of the setting member 20 to the second element 4 to be adjusted independently of the ball unit 34 relative to the setting member 20.
- the end face of the setting member is provided with an alien key junction (not shown in the drawing) accessible through the tool 36 for adjusting the ball unit 34, enabling both to be adjusted simultaneously.
- an alien key junction (not shown in the drawing) accessible through the tool 36 for adjusting the ball unit 34, enabling both to be adjusted simultaneously.
- One or both of the tool and key on the one hand, and the ball and setting member on the other can be locked for this purpose .
- the second element 4 will be installed in the caput of the femur as a separate exercise. If it is not already fitted, then the block 16 will be coupled to the element 4, and the element 2 laid against the femur with the ball seat 20 generally located on the axis 18 of the block 16. The setting member is then fitted to the block 16 and tightened against its seat with the elements 2 and 4 in place. With the threads on the block 16 being oppositely handled as noted above, rotation of the setting member can serve effectively simultaneously to set the angle between the two elements, and lock it against subsequent straightening.
- the angle of the set axis relative to the axis of the element 4 must be chosen carefully to enable sufficient adjustment to be made within the tolerence of the coupling used, normally a screw threaded coupling. Suitable angles are typically 7 between 8 and 15° with the preferred angle being around 10.5°. With the angle within this range, sufficient movement can be accommodated by the use of loosely engaging threads. Even if the ball seat 26 does not accommodate translational movement of the ball 22, a loose thread can quite safely accommodate the requisite pivotal movement .
- Respective bone sections can be coupled by appropriate bone screws to components which are themselves coupled by means of a joint according to the invention. The joint will allow individual adjustment to alter the relative orientation of the bone sections to be fixed.
Landscapes
- Health & Medical Sciences (AREA)
- Orthopedic Medicine & Surgery (AREA)
- Surgery (AREA)
- Life Sciences & Earth Sciences (AREA)
- Heart & Thoracic Surgery (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Neurology (AREA)
- Medical Informatics (AREA)
- Molecular Biology (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Prostheses (AREA)
- Surgical Instruments (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000532074A JP4119091B2 (en) | 1998-02-23 | 1999-02-23 | Femoral compression screw assembly and joint therefor |
EP99906340A EP1063934A1 (en) | 1998-02-23 | 1999-02-23 | Hip compression screw assemblies and joints therefor |
AU26311/99A AU2631199A (en) | 1998-02-23 | 1999-02-23 | Hip compression screw assemblies and joints therefor |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9803747.6 | 1998-02-23 | ||
GBGB9803747.6A GB9803747D0 (en) | 1998-02-23 | 1998-02-23 | Hip compression screw assemblies and joints therefor |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999042053A1 true WO1999042053A1 (en) | 1999-08-26 |
Family
ID=10827420
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1999/000545 WO1999042053A1 (en) | 1998-02-23 | 1999-02-23 | Hip compression screw assemblies and joints therefor |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP1063934A1 (en) |
JP (1) | JP4119091B2 (en) |
AU (1) | AU2631199A (en) |
GB (1) | GB9803747D0 (en) |
WO (1) | WO1999042053A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6916323B2 (en) | 2001-08-21 | 2005-07-12 | Depuy Products, Inc. | Method and apparatus for percutaneously securing a bone screw and a bone plate to a bone of a patient |
US8926611B2 (en) | 2009-09-14 | 2015-01-06 | Zimmer Gmbh | Angular lag implant for intramedullary nails |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP7000248B2 (en) | 2018-05-29 | 2022-01-19 | Ykk Ap株式会社 | Folding door |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2442185A (en) * | 1944-05-11 | 1948-05-25 | Szerenyi Andrew | Compass for use in drafting |
WO1998001078A1 (en) | 1996-07-04 | 1998-01-15 | Vagn Erik Dall | Hip compression screw assemblies and joints therefor |
-
1998
- 1998-02-23 GB GBGB9803747.6A patent/GB9803747D0/en not_active Ceased
-
1999
- 1999-02-23 WO PCT/GB1999/000545 patent/WO1999042053A1/en active Application Filing
- 1999-02-23 JP JP2000532074A patent/JP4119091B2/en not_active Expired - Fee Related
- 1999-02-23 AU AU26311/99A patent/AU2631199A/en not_active Abandoned
- 1999-02-23 EP EP99906340A patent/EP1063934A1/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2442185A (en) * | 1944-05-11 | 1948-05-25 | Szerenyi Andrew | Compass for use in drafting |
WO1998001078A1 (en) | 1996-07-04 | 1998-01-15 | Vagn Erik Dall | Hip compression screw assemblies and joints therefor |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6916323B2 (en) | 2001-08-21 | 2005-07-12 | Depuy Products, Inc. | Method and apparatus for percutaneously securing a bone screw and a bone plate to a bone of a patient |
US7431731B2 (en) | 2001-08-21 | 2008-10-07 | Depuy Products, Inc. | Method and apparatus for percutaneously securing a bone screw and a bone plate to a bone of a patient |
US7955361B2 (en) | 2001-08-21 | 2011-06-07 | Depuy Products, Inc. | Method and apparatus for percutaneously securing a bone screw and a bone plate to a bone of a patient |
US8926611B2 (en) | 2009-09-14 | 2015-01-06 | Zimmer Gmbh | Angular lag implant for intramedullary nails |
Also Published As
Publication number | Publication date |
---|---|
JP2002503514A (en) | 2002-02-05 |
EP1063934A1 (en) | 2001-01-03 |
AU2631199A (en) | 1999-09-06 |
JP4119091B2 (en) | 2008-07-16 |
GB9803747D0 (en) | 1998-04-15 |
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