US 2003/0191466 A1 · Orthopaedic fixation method and device

Abstract

Embodiments of the present invention include devices and methods for aligning fragments of a fractured bone or for positioning bones. In some embodiments, fixation devices and anatomical features are modeled with the aid of a computer, and the model is used to determine how an actual fixation device should be configured to align or position the bones.

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Claims68

Dependent claims

An external orthopaedic fixation device in combination with a computer, the combination for aligning fragments of a fractured bone comprising:

a first fixation element for coupling to a first bone fragment;
a second fixation element for coupling to a second bone fragment;
a first adjustable length strut coupled at its first end to the first fixation element and coupled at its second end to the second fixation element;
a second adjustable length strut coupled at its first end to the first fixation element and coupled at its second end to the second fixation element;
a third adjustable length strut coupled at its first end to the first fixation element and coupled at its second end to the second fixation element;
a fourth adjustable length strut coupled at its first end to the first fixation element and coupled at its second end to the second fixation element;
a fifth adjustable length strut coupled at its first end to the first fixation element and coupled at its second end to the second fixation element;
and
a sixth adjustable length strut coupled at its first end to the first fixation element and coupled at its second end to the second fixation element;
wherein when the first bone fragment and the second bone fragment are out of alignment, at least two of the first, second, third, fourth, fifth, and sixth adjustable length struts are different lengths, and if the first, second, third, fourth, fifth, and sixth adjustable length struts were any same length, the first bone fragment and the second bone fragment would be out of alignment;
wherein the combination is operable to bring the first bone fragment into alignment with the second bone fragment by:
storing the relative locations of the first fixation element and the first bone fragment,
storing the locations of the couplings of the first ends of the first, second, third, fourth, fifth, and sixth adjustable length struts relative to the first fixation element,
storing the relative locations of the second fixation element and the second bone fragment,
storing the locations of the couplings of the second ends of the first, second, third, fourth, fifth, and sixth adjustable length struts relative to the second fixation element,
spatially associating the stored location of the first fixation element with the stored location of the second fixation element,
aligning a computer generated representation of the stored location of the first bone fragment relative to a computer generated representation of the stored location of the second bone fragment,
obtaining the respective distances in the aligned computer generated representations between the first and second ends of the first, second, third, fourth, fifth, and sixth adjustable length struts respectively, and
providing the aligned lengths of the first, second, third, fourth, fifth, and sixth adjustable length struts to a user for adjusting the adjustable length struts of the external orthopaedic fixation device.

16 more elements

A method of configuring an orthopaedic fixation device that can be coupled to fragments of a fractured bone comprising the acts of:

representing a first fixation element of the fixation device virtually in three-dimensional space;
representing a first bone fragment virtually in three-dimensional space;
spatially associating the representation of the first fixation element with the representation of the first bone fragment;
representing a second fixation element of the fixation device virtually in three-dimensional space;
representing a second bone fragment virtually in three-dimensional space;
spatially associating the representation of the second fixation element with the representation of the second bone fragment;
spatially associating the representation of the first bone fragment with the representation of the second bone fragment;
aligning the virtual representation of the first bone fragment with the virtual representation of the second bone fragment while tracking the spatially associated locations of the representation of first fixation element and the representation of the second fixation element;
and
configuring the orthopaedic fixation device such that the first fixation element is in the same relative position to the second fixation element as the aligned representation of the first fixation element is with the aligned representation of the second fixation element.

7 more elements

A method of determining adjustments required to align fragments of a fractured bone coupled in an orthopaedic fixation device that has a first fixation element coupled to a second fixation element by at least three struts, each strut coupled at its first end to the first fixation element and at its second end to the second fixation element, comprising the acts of:

representing the first fixation element in a computer;
representing a first bone fragment in the computer;
spatially associating the first fixation element with the first bone fragment;
representing the second fixation element in the computer;
representing a second bone fragment in the computer;
spatially associating the representation of the second fixation element with the representation of the second bone fragment;
spatially associating the representation of the first bone fragment with the representation of the second bone fragment;
aligning the representation of the first bone fragment with the representation of the second bone fragment;
determining the location of the representation of the first fixation element relative to the representation of the second fixation element subsequent to the aligning of the representation of the first bone fragment and the representation of the second bone fragment;
determining the distance between the couplings of each of the at least three struts to the representation of the first fixation element and the representation of the second fixation element;
and
determining the amount to adjust each of the at least three struts to equal the determined distance between couplings.

9 more elements

A digital computing device programmed to provide data to a user for adjusting an orthopaedic fixation device that can be coupled to fragments of a fractured bone comprising:

a motherboard;
a central processing unit electrically coupled to the motherboard for executing program instructions;
a monitor electrically coupled to the motherboard for displaying representations of the fixation device;
and
a memory device electrically coupled to the motherboard that stores program instructions that enable the computing device to:
represent a first fixation element of the fixation device virtually in three-dimensional space;
represent a first bone fragment virtually in three-dimensional space;
spatially associate the virtual representation of the first fixation element with the virtual representation of the first bone fragment;
represent a second fixation element of the fixation device virtually in three-dimensional space;
represent a second bone fragment virtually in three-dimensional space;
spatially associate the virtual representation of the second fixation element with the virtual representation of the second bone fragment;
spatially associate the virtual representation of the first bone fragment with the virtual representation of the second bone fragment;
align the virtual representation of the first bone fragment with the virtual representation of the second bone fragment while tracking the spatially associated locations of the virtual representation of first fixation element and the virtual representation of the second fixation element;
and
output data specifying how the first fixation element is to be positioned relative to the second fixation element to align the first bone fragment and the second bone fragment

12 more elements

A program storage device containing instructions that enable a computer to provide data specifying how to configure an orthopaedic fixation device that can be coupled to fragments of a fractured bone, the instructions comprising the acts of:

representing a first fixation element of the fixation device virtually in three-dimensional space;
representing a first bone fragment virtually in three-dimensional space;
spatially associating the virtual representation of the first fixation element with the virtual representation of the first bone fragment;
representing a second fixation element of the fixation device virtually in three-dimensional space;
representing a second bone fragment virtually in three-dimensional space;
spatially associating the virtual representation of the second fixation element with the second bone fragment;
spatially associating the virtual representation of the first bone fragment with the second bone fragment;
aligning the virtual representation of the first bone fragment with the virtual representation of the second bone fragment while tracking the spatially associated locations of the virtual representation of the first fixation element and the virtual representation of the second fixation element;
and
providing data specifying how to configure the orthopaedic fixation device such that the first fixation element is in the same relative position to the second fixation element as the virtual representation of the first fixation element is with the aligned, virtual representation of the second fixation element after the virtual representations of the bone fragments have been aligned.

7 more elements

A method of configuring a multi-strut orthopaedic fixation device that can be coupled to fragments of a fractured bone comprising the acts of:

representing a first fixation element of the fixation device virtually in three-dimensional space;
representing a first bone fragment virtually in three-dimensional space;
spatially associating the representation of the first fixation element with the representation of the first bone fragment;
representing a second fixation element of the fixation device virtually in three-dimensional space;
representing a second bone fragment virtually in three-dimensional space;
spatially associating the representation of the second fixation element with the representation of the second bone fragment;
spatially associating the representation of the first bone fragment with the representation of the second bone fragment;
configuring the representation of the multi-strut orthopaedic fixation device to any neutral frame configuration while tracking the fixation elements and bone fragments;
noting virtual deformity parameters of the bone fragments with the multi-strut orthopaedic fixation device virtually configured to a neutral frame;
solving for correcting strut lengths by aligning virtual representations of the virtually altered representations of the bone fragments while tracking the representations of the spatially associated fixation elements and calculating the resulting strut lengths.

7 more elements

Dependencies are inferred from the claim text.

Description8,958 words

Summary2,977 words

#Embodiments of the invention are directed to treating musculoskeletal conditions, including skeletal fractures. More specifically, apparatuses and methods for securing and placing fragments of a fractured bone or bones on two sides of a joint in desired locations are disclosed. In some embodiments of the invention, apparatuses and methods are used to generate a computer model of a fixation device and bones or bone fragments. Through operations on the model, desired placement of the bones or bone fragments is determined quickly and accurately regardless of the initial configuration of the fixation device. The operations required to create the desired placement of the bones or bone fragments may then be enacted on a corresponding physical device to treat the musculoskeletal condition.

#Devices and methods of treating skeletal fractures using ring external fixation structures are well known in the art. Smith & Nephew, Inc. has developed and marketed a number of SPATIAL FRAME® brand external ring fixators based on the general concept of a Stewart platform. Smith & Nephew, Inc. owns U.S. Pat. Nos. 5,702,389; 5,728,095; 5,891,143; 5,971,984; 6,030,386; and 6,129,727 that disclose many basic concepts of and improvements to Stewart platform based external fixators. The disclosure of those patents is incorporated by reference herein.

#As will be appreciated by one skilled in the art, mathematically solving for the relative positions of the members of a Stewart platform creates a somewhat cumbersome equation. As an example, note the rotational matrix detailed in U.S. Pat. No. 5,971,984. This rotational matrix is a means by which one Stewart platform fixation element can be transformed relative to another to align fragments of a bone with inputs commonly obtainable from a clinical examination. However, in order to use the rotational matrix, a starting position for the fixation elements must be known. Therefore, prior art systems typically have required a Stewart platform type ring fixator to either start or end its transformation in a neutral position. A neutral position is a position where all of the six struts are the same length, and consequently, the rings of the fixator are parallel to one another. See FIGS. 4 and 5. A neutral position makes locating the starting positions of the fixation elements readily calculable. Once the frame moves beyond neutral, Cartesian coordinates of the frame components are difficult to find mathematically. This limitation results in complexity with regard to a mathematical solution for a Stewart platform. As a practical matter, it means that in the past, supposed correction solutions that did not in fact solve a particular deformity were very difficult to secondarily correct. This situation will be described in more detail below as a “crooked-frame/crooked-bone” situation. A solution for the crooked-frame/crooked-bone situation will be described as a “total residual” solution.

Brief description of the drawings29 figures

#FIG. 1 is a perspective view of an orthopaedic fixation device.

#FIG. 2 is a perspective view of an orthopaedic fixation device coupled to a tibia.

#FIG. 3 is a system diagram of an orthopaedic fixation device in combination with a computer.

Detailed description5,309 words

#FIG. 1 shows an external orthopaedic fixation device 100 useful for aligning fragments of a fractured bone. The device shown is a Stewart platform based ring fixator device. Smith & Nephew, Inc. markets the particular device shown as a SPATIAL FRAME® brand or TAYLOR SPATIAL FRAME® brand external fixator. The fixation device 100 includes a proximal ring or first fixation element 10 and a distal ring or second fixation element 20. In other embodiments of the invention, the proximal ring could be the second fixation element and the distal ring could be the first fixation element. In FIG. 1, the first fixation element 10 is coupled to the second fixation element 20 by six adjustable length struts 1-6. Each of the struts 1-6 is coupled at its first end to the first fixation element 10 and at its second end to the second fixation element 20.

#FIG. 2 illustrates the first fixation element 10 coupled to a first bone fragment 11, and the second fixation element 20 coupled to a second bone fragment 21. As shown, the bone fragments are coupled to the fixation elements using cantilevered bone pins 13. In other embodiments, wires, bilateral pins, or any variety of coupling devices effective to secure a bone relative to a fixation element may be used. The fixation device 100 shown is coupled to a tibia; however, the device may be used on practically any bone on which it could be placed. For example, and without limitation, the device could also be used on a femur or a humerus.

#FIG. 3 shows the fixation device 100 in combination with a computer 200. Such a combination is useful to align fragments of a fractured bone. The computer 200 may be an autonomously operating computer system such as, for example, first computer system 201. All storage, processing, etc. necessary to align fragments of a fractured bone may be accomplished with the first computer system 201. In other embodiments, two or more computers may be linked together over a network to accomplish tasks necessary to align the fragments. As shown, computer systems 201 and 202 are linked over a network 203. The network may be a local area network or a wide area network such as the Internet. In some embodiments, all of the programs that are run to accomplish the tasks may be run on one or more of the computer systems, and another of the computer systems may merely be used to display data. Alternatively, the programs run may be run partially on several computer systems, with data and instructions being shared over the network.

Orthopaedic fixation method and device

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Orthopaedic fixation method and device

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Abstract

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Claims68

Description8,958 words

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Classification3 codes

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Description8,958 words