|Title of Invention||
EXTERNAL FIXATOR ASSEMBLY FOR TIBIAL FRACTURE
|Abstract||This invention relates to a new external fixator for treating tibial fractures. It comprises two vertically disposed frame members provided inwardly with two supplementary stiffeners. The main and the supplementary members have clamp like means for holding pins inserted pins inserted there through. The two main frame members are inter-connected at the top and the bottom with horizontal and diagonal members to provided required rigidity when assembled.|
This invention relates to an external fixator assembly for tibial fracture.
Unilateral biplanar external fixators are conventionally used in orthopaedic treatment of fractures of the tibia, a bone in the leg. One of the popular methods of treatment for mending broken tibia consists of rigidly connecting and supporting the broken tibia with the help of two vertical steel rods and multiple steel pins. Each rod is connected to the bone by two separate sets of pins located on either side of the fracture site. Each rod with its associated set of pins forms a frame in one plane. The two rods along with the associated pins constitute a biplanar assembly with an included angle which is generally close to 90o. Optionally these two frame members are interconnected diagonally by means of rods disposed at the top and bottom of the frame members.
The main purpose of such a fixator is to hold the fractured segments of the tibia in proper alignment during the process of healing and to bear loads without displacing the fracture. However, problems of malunion, non-union, delayed union, malalignment, pin loosening and consequent pin tract infection are some of the practical problems noticed while using the
conventional biplanar fixators. These drawbacks are largely attributed to the inadequate rigidities of the fixators. Loading in the axial, latero-medial, antero-posterior and torsional modes also result in significant displacement of the fracture site.
The above discussed drawbacks of the conventional unilateral biplanar f ixators can be avoided by increasing the rigidity of the frame members and this objective is achieved by providing additional or supplementary stiffeners, both horizontally and vertically. The external fixator assembly developed by us provides at least two additional stiffeners or support members positioned between the fractured bone and each of the main vertical member or rod. Two horizontal members are disposed at the top and bottom of the biplanar fixator to diagonally connect the two main vertical frame members or rods. Pins that bridge the fracture are positioned on the main vertical frame members and are interconnected with the vertical supplementary stiffeners.
The external fixator assembly for tibial fracture according to this invention comprises at least one vertically disposed main frame members provided with means for mounting pins thereon, characterised in that each of the main frame members are provided with a vertically and inwardly disposed supplementary stiffening
member, the said supplementary stiffening memoers also being provided with means for mounting pins, and at least one horizontal and diagonal members interconnecting the two main frame members at the top and the bottom of the said assembly.
The frame members may be rods made of stainless steel and clamp like means are provided for holding the pins which are to be drilled through the bones when the assembly is to be used. The clamps of the main frame members and that of the supplementary stiffening members are adjacently disposed to allow the same pin to pass there through.
The invention will now be described with reference to the figures in the accompanying drawings.
Figure I represents the conventional external fixators known in the art, wherein reference numerals 1, 1\ 2 and 3 represent the vertical frame member, the clamp means for holding pins and the pins held by the clamp. This figure represents the unit in the assembled position. B represents the fractured bone which is to be treated. Reference numeral 4 stands for two diagonally and horizontally disposed members interconnecting the frame members 1, This is an optional and not an essential feature of the conventional unit.
Figure II represents the fixator assembly of this invention. Reference numerals 1, 1', 2, 3 and 4 represent the vertical frame members, means for housing the pins, pins housed therein and the horizontally disposed member connecting the main frame member 1 and 1'. Reference numeral 5 stands for the supplementary stiffening member. It is to be understood that horizontal member is an essential feature in our invention and this in combination with the supplementary stiffeners enhance the rigidity of the fixator. B stands for the tibial bone on which the assembly is fixed.
It is established analytically, experimentally and clinically that the improved fixator has substantially increased rigidity. This ensures that bone fragments remain in proper alignment and that the pins do not become loose thereby reducing pin tract infection. Yet another advantage is that fewer pins are required and may be located further from the fracture site, thus providing room for soft tissue management. Enhanced rigidity of the novel fixator is derived from the integral action of all the components and due to each of the components functioning independently.
Though the invention has been described hereinabove with a specific embodiment, obvious equivalents known to persons skilled in the art are not excluded therefrom and from the appended claims.
1. An external fixator assembly for tibial fracture comprising at least one vertically disposed main frame members provided with means for mounting pins thereon, characterised in that each of the main frame members are provided with a vertically and inwardly disposed supplementary stiffening member, the said stiffening members also being provided with means for mounting pins, and at least one horizontal and diagonal members interconnecting the two main frame members at the top and the bottom of the said assembly.
2. The external fixator assembly as claimed in claim 1, wherein the. means for mounting pins are clamps.
3. The external fixator assembly as claimed in claims 1 and 2, wherein the frame members and the supplementary stiffening members are stainless steel rods.
4. The external fixator assembly as claimed in any of the preceding claims wherein the means for mounting pins on the main frame and supplementary sitffening members are adjacently located to allow the same pin to pass therethrough.
5. An external fixator assembly for tibial fracture substantially as herein described, with particular reference to Fig.II of the accompanying drawings.
Dated this 30th day of April 1997
|Indian Patent Application Number||915/MAS/1997|
|PG Journal Number||30/2009|
|Date of Filing||30-Apr-1997|
|Name of Patentee||M/S. CALICUT REGIONAL ENGINEERING COLLEGE|
|Applicant Address||KOZHIKODE 673601, KERALA|
|PCT International Classification Number||A61F 5/04|
|PCT International Application Number||N/A|
|PCT International Filing date|