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
  • A61B17/60—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 for external osteosynthesis, e.g. distractors, contractors
  • A61B17/64—Devices extending alongside the bones to be positioned
  • A61B17/6466—Devices extending alongside the bones to be positioned with pin-clamps movable along a solid connecting rod
  • A61B17/6475—Devices extending alongside the bones to be positioned with pin-clamps movable along a solid connecting rod the connecting rod being threaded
• • 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
  • A61B17/60—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 for external osteosynthesis, e.g. distractors, contractors
  • A61B17/64—Devices extending alongside the bones to be positioned
  • A61B17/6458—Devices extending alongside the bones to be positioned with pin-clamps fixed at ends of connecting element

Definitions

• This invention relates to a post-fracture bone fixator.
• post-fracture bone fixators or ⁇ stabilisers There have been a number of proposals described in the literature relating to post-fracture bone fixators or ⁇ stabilisers. For example reference may be made to British Patent Specifications Nos. 567715, 1480167, and 2029702A.
• a device known as the Oxford fixator is described in a paper in "Engineering in
• the present invention seeks to provide a post-fracture bone fixator or stabiliser combining strength, lightness, and low bulk with ease of adjustment, in practice, so as to allow the patient to use the broken limb as quickly as possible.
• OMPI of a lockable ball and socket joint the ball being formed from a rigid material and the material of the socket comprising an elastomeric material.
• the fixator comprises two pin clamps, each lockably mounted on the support by means of a lockable ball and socket joint, the ball being formed from a rigid material and the material of the socket comprising an elastomeric material.
• the ball of the or each ball and socket joint is carried by the pin clamp and is provided with surface indentations, for example crevices which extend in both latitudinal and longitudinal directions around the ball.
• each pin clamp is preferably adapted to receive a plurality of skeletal or Steinman pins, for example three skeletal pins, in spaced, substantially parallel relationship to one another.
• each pin clamp comprises a block of elastomeric material, which has a rigid plate embedded therein, a clamping plate for clamping the skeletal pins against the block of elastomeric material, and means adapted to co-operate with the rigid plate to urge the clamping plate into clamping engagement with the block.
• the ball of the lockable ball and socket joint is preferably located in the pin clamp by means of the rigid plate and the means adapted to co-operate with the rigid plate comprises a pair of bolts adapted to engage screw threadedly in the rigid plate.
• the socket is preferably formed in a block of elastomeric material which comprises a pair of jaws, each of which is formed with a surface that .is complementary to that of the ball, and means for drawing the jaws one towards the other to lock the ball therebetween; such complementary surfaces may each be substantially part-spherical.
• the means for drawing the jaws one towards the other may comprise a rigid plate embedded in one of the jaws and bolt means adapted to bear against the other jaw and to engage screw threadedly in said rigid plate in said one jaw.
• the other jaw may also be provided with a rigid plate embedded therein.
• the elongate support comprises a rigid rod having a connector device corresponding to each pin clamp detachably mounted thereon, the lockable ball and socket joint being arranged to connect the respective pin clamp to the corresponding connector device.
• Each such pin clamp may be provided with the ball of the corresponding ball and socket joint, the socket of which is formed in the connector device.
• at least one of the connector devices is adjustable in position on the rod.
• the rod is threaded over at least a portion of its length and carries a pair of nuts for releasably securing the connector device to the rod in a selected position.
• the connector device preferably has a bore therethrough for snugly receiving the rod.
• the rod may be keyed in the bore through the connector device so as to restrict rotational movement of the connector device about the axis of the rod.
• the bore through the connector device may be non-circular (e.g. of D-section) and the rod is of corresponding cross-section (e.g. of D-section) over at least a portion of its length.
• the connector device may comprise a block of elastomeric material having a cylindrical sleeve embedded therein for receipt of the rod, which sleeve is partly filled with elastomeric material forming part of the block so as to render the bore non-circular.
• the bore in the connector device may be formed in a portion which is offset longitudinally of the connector device with respect to the ball and socket joint. In this way reversal of one or both of the connector devices upon the rod can be used to obtain adjustment of the positions of the pin clamps relative to one another.
• the pin clamp is adapted to clamp a plurality of skeletal pins extending transversely of the- in clamp and the ball and socket joint is .arranged offset longitudinally of the pin clamp. By rotating one or both of the pin clamps through 180° about its respective ball and socket joint the distance between the pin clamps can be quickly adjusted.
• the elongate support comprises a pair of connector devices each having a screw threaded rod extending therefrom and a turnbuckle device for adjusting the distance between the connector devices.
• the threads on the two rods are of opposite hand one to another.
• lock nuts are provided to secure the turnbuckle device and the connector devices one to another.
• each connector device has the ball of the .ball and socket joint integrally formed therewith and the socket joint is formed in an end of a corresponding pin clamp.
• Figure 1 is a side view of a post-fracture • * bone fixator constructed in accordance with the present invention
• Figure 2 is a plan view of the fixator of Figure 1;
• Figure 3 is an end view of the fixator of Figures 1 and 2;
• Figure 4 is a detail view of the ball of the lockable ball and socket joint of a modified form of fixator;
• Figure 5 is a side view of a drilling guide for use with the fixator of Figures 1 to 4;
• Figure 6 is a top plan view of the drilling guide of Figure 6;
• Figure 7 is a side view of a second form of fixator.
• a post-fracture bone fixator comprises an elongate stainless steel rod 1, each end of which is threaded, as indicated at 2 and 3.
• Each of the threaded ends 2 and 3 of the rod 1 is machined to provide a corresponding flat running surface 4 and 5 respectively; thus the threaded portions 2 and 3 of the rod l ' are of D-section.
• the two connector devices 6 and 7 are of similar construction but of opposite hand.
• Each of the connector devices 6 and 7 comprises a block moulded from a suitable elastomeric material.
• elastomeric material comprises a synthetic rubbery polymeric material, for example one of the commercially available twin-pack synthetic rubbers which polymerise exother ally upon mixing the polymer component and cross linking agent prior to pouring the mixture in the mould.
• the elastomeric material should be a hard elastomeric material, preferably a material having a Shore hardness of at least 50, and even more preferably at least about 60. Particularly preferred materials have a Shore hardness in the range of from about 68 (Shore A) to about 78 (Shore D).
• the elastomeric material should be capable of being autoclaved without deformation or significant detrimental effect upon its properties upon recooling to room temperature.
• a suitable material is that sold under the trade mark
• Vulkollan more particularly a “Vulkollan” material which is formulated to produce a cured polymer having a Shore hardness of about 70 (Shore A).
• the material may contain a pigment, such as carbon black; this has the advantage that any discolouration of the polymer in use due to the influence of light or heat is masked by the presence of the pigment.
• connector device 6 is formed with a longitudinal slit in it so as to form a pair of jaws 12 and 13.
• Each jaw 12,13 has a corresponding stainless steel plate 14,15 embedded therein.
• a pair of bolts 16,17 are threadably engaged in the plate 14 and pass freely through corresponding apertures in the plate 15.
• Reference numeral 18. indicates washers on each of bolts 16,17.
• Each of jaws 12,13 has a hollowed out portion, as indicated at 19,20 in Figure 3, each having a part- spherical surface, so as to form together the socket of the lockable ball and socket joint. This joint allows considerable azimuthal adjustment of the corresponding pin clamp 8,9.
• Ball 21 of the ball and socket joint is - • carried by the pin clamp 8.
• Ball 21 is made of stainless steel and is formed with a series of surface grooves which extend both latitudinally and longitudinally with respect to the polar axis of the ball.
• Ball 21 is formed integrally with a flange 22 an with a shank 23 which carries a flange 40, having chamfered sides 41 (see Figure 2), and has at its end a screw threaded portion 24, the axis of which coincides with the polar axis of ball 21.
• ball 21 is secured in a stainless steel plate 25 which is embedded in the block of polymeric material (e.g. Vulkollan 70) from which the body of pin clamp 8 is formed.
• Pin clamp 8 has three transverse grooves 26,27,28 formed in the upper surface thereof. These are adapted to receive each a corresponding skeletal or Steinman pin (not shown). Grooves 26,27 and 28 are aligned parallel one to another.
• Clamping of the skeletal or Steinman pins is achieved by means of a clamping plate 29 and clamping bolts 30,31 which pass through corresponding holes in clamping plate 29 into the pin clamp 8 and are threadably received in corresponding threaded bores in plate 25.
• Reference numeral 32 indicates washers on bolts 30,31.
• Connector device 6 has a cylindrical sleeve 33 embedded therein, the internal diameter of which corresponds to the diameter of rod 1.
• Sleeve 33 has a *• •
• Reference numeral 36 indicates washers embedded one at each end of sleeve 33 in the elastomeric material from which
• connector device 7 Two nuts 37,38 are threaded upon threaded portion 2, being arranged one on each side of connector device 6 to lock the same upon threaded portion 2.
• the construction of connector device 7 is
• Pin clamp 9 is essentially similar to pin clamp 8 and the construction, of ball and socket joint 11 • • is similar to that of ball and socket joint 10.
• pin clamp 9 has been reversed by rotation through 180° about the polar axis of the ball of ball and socket joint 11, compared with pin clamp 8. As will be described below, this rotational movement provides a convenient means of adjusting the fixator for the surgeon during the course of a surgical operation.
• Figure 4 shows the ball 101 of a modified for of fixator.
• the longitudinal grooves 102 and the latitudinal grooves 103 are clearly visible.
• Figure 5 shows a drilling guide for use in conjunction with the fixator of Figures 1 to 3.
• This comprises a generally rectangular yoke piece 110, conveniently formed of carbon black-filled Vulkollan 70, having six metal sleeves 111 moulded therein.
• the sleeves 111 are arranged in pairs so as to provide three accurately parallel passages each for guiding a skeletal or Steinman pin during drilling and insertion of the pin through the corresponding part of the bone fracture.
• the spacing between sleeves 111 corresponds exactly to the spacing between the slots 26,27,28 and the space 112 within yoke piece 110 is designed to receive snugly either of the pin clamps 8,9.
• the surgeon will use the drill guide 110 for insertion of the skeletal or Steinman pins into the parts of the bone fracture concerned. Most commonly this will be a tibia. However the fixator of Figures 1 to 3 can also be used in connection with fractures of the ulna, radius or humerus. Usually it will be convenient to insert first the middle pin, i.e. the one to occupy the groove 27, in the first set of three pins. Having inserted one set of three pins, one of the pin clamps 8 or 9 can be fixed to the first set of three pins and the other set of pins inserted in the other part of the bone fracture, using the guide 110 as before, having possibly first positioned this by fitting it over the other pin clamp 9 or 8 as the case may be.
• either or both of the pin clamps 8,9 can be rotated about the corresponding ball and socket joint from the position shown in Figure 1 to compensate for differences in length of the bone in which the fracture has occurred.
• the clamps 8,9 are both in a position similar to that of clamp 9 in Figure 1 and are then both rotated about the corresponding ball and socket joint 10,11 through 180° so that each ends up in a position corresponding to that of clamp 8 in Figure 1, then it -will be found that the positions of the outermost skeletal pins can differ by about 3 cm. This is a very easy way to obtain extra distance, either positive or
• OMPI negative when constructing a scaffold around a bone fracture. Further adjustment can be obtained by moving connector devices 6 and 7 along the threaded portions 2 and 3.
• the use of nuts 37,38 on the rod 1 allows easy and precise movement of the connector devices 6,7, after the fixator has been attached to the patient, and the distance between the pin clamps 8,9 on the separate parts of the bone fracture can be reduced or lengthened by a fraction, or by a multiple, of the screw pitch. Further adjustment still is provided by reversing connector device 6 and/or 7 on the rod 1 from the positions shown in Figure 1 as the surgeon may require.
• the fixator illustrated in Figures 1 to 3 is suitable for use in cases of fracture in bones of varying length, it may be expedient to use a longer or shorter rod 1 than that illustrated.
• Figure 7 illustrates a further embodiment according to the invention.
• This comprises two pin clamps 201, the construction of which is similar to that of pin clamps 8,9 of the embodiment of Figures 1 to 3.
• Grooves 202,203,204 are provided to receive the skeletal or Steinman pins which are held in place by means of clamping plate 205 and bolts 206,207.
• each pin clamp 201 has a pair of jaws 208; in ' Figures 7 only one jaw 208 of each pair is visible.
• the construction of jaws 208 is similar to that of the jaws 12,13 of the fixator of Figures 1 to 3.
• Jaws 208 each have a metal plate (not shown) embedded therein, similar to plates 14,15 and are formed with part-spherical recesses to form a socket of a lockable ball and socket joint, the ball of which is illustrated at 209. Jaws 208 can be drawn towards one another to clamp the ball 209 by means of bolts, the shanks of which are indicated at 210.
• Balls 209 are formed each at one end of a respective one of a pair of threaded rods 211 and 212.
• the thread on rod 211 has an opposite hand to that of the thread on rod 212.
• a turnbuckle device 213 is engaged with the free ends of the rods 211 and 212.
• Reference numerals 214 and 215 indicate lock nuts.
• balls 209 are formed with longitudinal and latitudinal crevices similar to those illustrated in Figure 4.
• fixator of Figure 7 The method of use of the fixator of Figure 7 is similar to that described in relation to the fixator of Figures 1 to 3. In this case, however, adjustment of the length of the elongate member formed by the rods 211 and 212 and the turnbuckle 213 can be adjusted by means of the turnbuckle 213 and this latter can be fixed in place by means of lock nuts 214,215.

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• Health & Medical Sciences (AREA)
• Orthopedic Medicine & Surgery (AREA)
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• 1983
  • 1983-01-27 WO PCT/GB1983/000014 patent/WO1983002554A1/en unknown
  • 1983-01-27 EP EP19830900495 patent/EP0099391A1/de not_active Withdrawn
  • 1983-01-27 AU AU11561/83A patent/AU1156183A/en not_active Abandoned

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