Title of Invention	DYNAMIC EXTERNAL WRIST FIXATOR
Abstract	The dynamic external wrist fixator of this invention consists okf \wo hingedly connected frame members. Pin-gripping units are dis,posed on these frame members in a longitudinally displaceable ~anner. The free end of the first frame member has a tensioning means for adjusting the pin gripping unit. The hinge means consists of a three way adjusting and fastening means for controlling multiplanar ligamentotaxis of the wrist.

Title of Invention

DYNAMIC EXTERNAL WRIST FIXATOR

Abstract

The dynamic external wrist fixator of this invention consists okf \wo hingedly connected frame members. Pin-gripping units are dis,posed on these frame members in a longitudinally displaceable ~anner. The free end of the first frame member has a tensioning means for adjusting the pin gripping unit. The hinge means consists of a three way adjusting and fastening means for controlling multiplanar ligamentotaxis of the wrist.

Full Text	This Invention relates to dynamic external wrist fixator which Is a device meant for orthopaedic treatment of unstable fractures of the distal radius or the wrist bone through external fixation. Treatment of unstable fractures of the wrist or the distal radius caused by high velocity injuries is very difficult. Different types of treatments are required depending on various factors such as the type of fracture, age and the lifestyle of the patient. Fracture, pattern, degree of communities, radial shortening and displacement, dorsal-palmar displacement and angulations and soft tissue involvement are also considered while deciding the typ e of treatment to be administered. The basic treatment principle is to obtain accurate fracture reduction, and to maintain the reduction while protecting the wrist to rehabilitate the hand. Plaster immobilization, functional bracing percutaneous pinning and external fixation are the different types of treatment currently in use. A conservative way of treating wrist fracture is by plaster immobilization and is accomplished by placing the wrist in some palmar flexion and ulnar deviation while moulding a cast over the posteriolateral wrist and anteromedial forearm. Deformity and malunion are often noticed in cases where the position of immobilization is not appropriately chosen. Functional bracing is carried out with the forearm in supination, thus allowing full palmar flexion of the wrist and full elbow flexion extension. This treatment is not fully satisfactory as it enhanced collapse of the fractured fragments and often resulted in swellings. Percutaneous pinning of fractured wrist does not yield satisfactory results. Delayed union and displacement are often observed in patients treated by this technique. External fixation is generally accepted as superior to other techniques of treating wrist fracture. Conventionally, external fixators apply traction and restore displacement. Most fixators use only longitudinal traction forces which are not capable of restoring palmar tilt. Though biplanar closing wedge osteomy with distal ulnar resection and carpal tunnel release as a combination procedure has been described, there remains a need for a device that permits management of the deformity in three planes. This dynamic external wrist fixator has been developed with a view to fulfil this objective of providing traction in all the three planes. This dynamic external fixator is different from the existing static and dynamic fixator in that it permits multi¬planar ligamentotaxis that can be finely tuned at any stage and that it facilitates controlled and protected mobilization of the wrist with the operation of one degree of freedom at a time. This device also facilitates the reduction and maintenance of the fracture and the realignment of the articular surfaces to an extent as anatomically possible. The external fixator according to this invention consists of a wrist bridging frame made of two separate members such as rods, inter-connected by a specially designed hinge means. This hinged means permits three degree freedom that can be controlled independently at any direction and is provided with locking means to lock the hinge means at the desired plane or position. The hinge means also enables the memJDer of the frame to be fixed at any orientation relative to each other. Each member of the frame is provided with a pin gripping unit and is disposed along the longitudinal axis of these members. These pin gripping units have the freedom to traverse longitudinally along this axis of the frame members. One of the members of the wrist frame has tensioning means such as a threaded nut for adjusting the longitudinal movement of the pin gripping unit housed thereon. This tensioning means is located at the free end of the first member or rod. The hinge means connecting the two members of the wrist frame have means for allowing three degree or directional fifeedom. It has an adjustable threaded nut and screw assembly, rotating about the longitudinal axis to adjust the length. Palmar and dorsi flexion of the wrist is controlled by another adjustable means located laterally on the second member/rod while the centre of the hinge means has an adjustable nut for regulating radial and ulnar deviation. The pin gripping means have sleeves through which pins can be drilled to the desired bones of the broken hand. The rods may have appropriate openings for housing the pin gripping means which are displacable longitudinally therein. The dynamic external wrist fixator according to this invention comprises a wrist frame consisting of at least two members inter-connected by hinge means, each of the said members having mounted thereon at least one longitudinally displaceable pin gripping unit, the free end of the first member being provided with a tensioning means for controlling the longitudinal movement of the pin gripping unit mounted thereon and the said hinge means consisting of three way adjusting and fastening means for controlling multiplanar ligamentotaxis of the wrist. The procedure for using the dynamic external wrist fixator will be described hereinafter. The wrist fixator assembly is positioned against the injured wrist with the rod containing the tensioning means on the hand side of the fracture and the other rod on the forearm side. The hinge mechanism connecting the two rods must be in line with the fulcrum of the wrist joint. The wrist is then kept in moderate palmar flexion and slight ulnar deviation. The rods and the pin gripping units are aligned in the desired manner and then locked with the help of fastening means in the hinge mechanism. Pins are then inserted through the sleeves provided in the pin gripping unit. Jigs known in the art may be used for drilling pins into the metacarpal bone and into the radius. Multi-planar ligamentotaxis is applied with the help of the adjusting means in the hinge to achieve preliminary fracture reduction. The wrist is then immobilised for a pferiod of three weeks. During this period, sustained fracture reduction can be obtained by adjusting the traction or tension mechanism periodically. After three weeks of immobilization, the patient is allowed to exercise and mobilise the wrist joint periodically by unlocking the adjusting nuts in the hinge mechanism. Care must be taken to operate only one nut at a time so that multiplanar movement is avoided. The pins and the fixators may be released after a lapse of six weeks. Multiplanar movement that is afforded by the device according to this invention minimises malunion of the fracture. This invention wHl now be described with reference to the figures in the accompanying drawings. Fig I shows the dynamic external wrist fixator wherein reference number 1 indicates the pin gripping unit. Reference numberals 2, 3 and 4 show the hinge means, the tensioning means and the pins respectively. R^ and R2 are the members or rods of the wrist frame hingedly connected. Fig II shows an exploded view of the hinge means showing the ends of the rods connected thereto. In Fig II (a) represents a * threaded nut, rotation of which controls the turning of the longitudinal axis of rod R^. Reference letter (b) indicates an adjusting means such as a threaded nut and screw which controls radial and lunar deviation of the wrist. Threaded nut (c) located by the rod Ro controls the palmar and dorsa flexion of the hand. By adjusting the tensioning means 3 and the adjusting means a, b and c, fracture reduction takes place. By periodically unlocking these adjusting means, it is also possible to provide the desired quantum of movement to the broken hand. This invention, though illustrated herein above with a particular embodiment includes obvious equivalents known to persons skilled in the art within the scope and ambit of the appended claims. We Claim: 1. A dynamic external wrist fixator comprising a wrist frame consisting of at least two members interconnected by hinge means, each of the said members having mounted thereon, at least one longitudinally displaceable pin gripping unit the free end of the first member being provided with a tensioning means for controlling the longitudinal movement of the pin gripping unit mounted thereon and the said hinge means consisting of three way adjusting and fastening means for controlling multiplanar ligamentotaxis of the wrist. 2. The dynamic external wrist fixator as claimed in claim 1, wherein the two members constituting the wrist frame are rods, provided with openings for housing the said pin gripping units in a longitudinally displaceable manner. 3. The dynamic external wrist fixator as claimed in claims 1 and 2 wherein the pin gripping means have sleeves for drilling pins therethrough. 4. The dynamic external wrist fixator as claimed in any of the preceding claims wherein the tensioning means is a threaded nut and screw assembly. 5. The dynamic external wrist fixator as claimed in any of the preceding claims wherein the hinge means has an adjusting and , fastening means oppositely disposed to the tensioning means for controlling the longitudinal axis by rotation. 6. The dynamic external wrist fixator as claimed in any of the preceding claims wherein the hinge means has a centrally located nut and screw assembly for controlling the radial and lunar deviation. 7. The dynamic external wrist fixator as claimed in claims 1 to 6, wherein an adjusting and fastening means such as a threaded nut and screw assembly is located lateraly on the second member of the wrist frame for controlling plalmar and dorsi flexion. 8. A dynamic external wrist fixator substantially as herein described, with particular reference to the accompanying drawings.

Full Text

This Invention relates to dynamic external wrist fixator
which Is a device meant for orthopaedic treatment of unstable
fractures of the distal radius or the wrist bone through external
fixation.
Treatment of unstable fractures of the wrist or the distal radius caused by high velocity injuries is very difficult. Different types of treatments are required depending on various factors such as the type of fracture, age and the lifestyle of the patient. Fracture, pattern, degree of communities, radial shortening and displacement, dorsal-palmar displacement and angulations and soft tissue involvement are also considered while deciding the typ e of treatment to be administered. The basic treatment principle is to obtain accurate fracture reduction, and to maintain the reduction while protecting the wrist to rehabilitate the hand. Plaster immobilization, functional bracing percutaneous pinning and external fixation are the different types of treatment currently in use.
A conservative way of treating wrist fracture is by plaster
immobilization and is accomplished by placing the wrist in
some palmar flexion and ulnar deviation while moulding a cast
over the posteriolateral wrist and anteromedial forearm.

Deformity and malunion are often noticed in cases where the position of immobilization is not appropriately chosen. Functional bracing is carried out with the forearm in supination, thus allowing full palmar flexion of the wrist and full elbow flexion extension. This treatment is not fully satisfactory as it enhanced collapse of the fractured fragments and often resulted in swellings. Percutaneous pinning of fractured wrist does not yield satisfactory results. Delayed union and displacement are often observed in patients treated by this technique.
External fixation is generally accepted as superior to other techniques of treating wrist fracture. Conventionally, external fixators apply traction and restore displacement. Most fixators use only longitudinal traction forces which are not capable of restoring palmar tilt. Though biplanar closing wedge osteomy with distal ulnar resection and carpal tunnel release as a combination procedure has been described, there remains a need for a device that permits management of the deformity in three planes.

This dynamic external wrist fixator has been developed with a view to fulfil this objective of providing traction in all the three planes. This dynamic external fixator is different from the existing static and dynamic fixator in that it permits multi¬planar ligamentotaxis that can be finely tuned at any stage and that it facilitates controlled and protected mobilization of the wrist with the operation of one degree of freedom at a time. This device also facilitates the reduction and maintenance of the fracture and the realignment of the articular surfaces to an extent as anatomically possible. The external fixator according to this invention consists of a wrist bridging frame made of two separate members such as rods, inter-connected by a specially designed hinge means. This hinged means permits three degree freedom that can be controlled independently at any direction and is provided with locking means to lock the hinge means at the desired plane or position. The hinge means also enables the memJDer of the frame to be fixed at any orientation relative to each other. Each member of the frame is provided with a pin gripping unit and is disposed along the longitudinal axis of these members. These pin gripping units have the freedom to traverse longitudinally along this axis of the frame members.

One of the members of the wrist frame has tensioning means such as a threaded nut for adjusting the longitudinal movement of the pin gripping unit housed thereon. This tensioning means is located at the free end of the first member or rod.
The hinge means connecting the two members of the wrist frame have means for allowing three degree or directional fifeedom. It has an adjustable threaded nut and screw assembly, rotating about the longitudinal axis to adjust the length. Palmar and dorsi flexion of the wrist is controlled by another adjustable means located laterally on the second member/rod while the centre of the hinge means has an adjustable nut for regulating radial and ulnar deviation. The pin gripping means have sleeves through which pins can be drilled to the desired bones of the broken hand. The rods may have appropriate openings for housing the pin gripping means which are displacable longitudinally therein.
The dynamic external wrist fixator according to this invention comprises a wrist frame consisting of at least two members inter-connected by hinge means, each of the said members having mounted thereon at least one longitudinally displaceable

pin gripping unit, the free end of the first member being provided with a tensioning means for controlling the longitudinal movement of the pin gripping unit mounted thereon and the said hinge means consisting of three way adjusting and fastening means for controlling multiplanar ligamentotaxis of the wrist.
The procedure for using the dynamic external wrist fixator will be described hereinafter.
The wrist fixator assembly is positioned against the injured wrist with the rod containing the tensioning means on the hand side of the fracture and the other rod on the forearm side. The hinge mechanism connecting the two rods must be in line with the fulcrum of the wrist joint. The wrist is then kept in moderate palmar flexion and slight ulnar deviation. The rods and the pin gripping units are aligned in the desired manner and then locked with the help of fastening means in the hinge mechanism.
Pins are then inserted through the sleeves provided in the pin gripping unit. Jigs known in the art may be used for drilling pins into the metacarpal bone and into the radius. Multi-planar ligamentotaxis is applied with the help of the adjusting means in

the hinge to achieve preliminary fracture reduction. The wrist is then immobilised for a pferiod of three weeks. During this period, sustained fracture reduction can be obtained by adjusting the traction or tension mechanism periodically.
After three weeks of immobilization, the patient is allowed to exercise and mobilise the wrist joint periodically by unlocking the adjusting nuts in the hinge mechanism. Care must be taken to operate only one nut at a time so that multiplanar movement is avoided. The pins and the fixators may be released after a lapse of six weeks.
Multiplanar movement that is afforded by the device according to this invention minimises malunion of the fracture.
This invention wHl now be described with reference to the figures in the accompanying drawings.
Fig I shows the dynamic external wrist fixator wherein reference number 1 indicates the pin gripping unit. Reference numberals 2, 3 and 4 show the hinge means, the tensioning means and the pins respectively. R^ and R2 are the members or rods of the wrist frame hingedly connected.

Fig II shows an exploded view of the hinge means showing the ends of the rods connected thereto. In Fig II (a) represents a * threaded nut, rotation of which controls the turning of the longitudinal axis of rod R^. Reference letter (b) indicates an adjusting means such as a threaded nut and screw which controls radial and lunar deviation of the wrist. Threaded nut (c) located by the rod Ro controls the palmar and dorsa flexion of the hand. By adjusting the tensioning means 3 and the adjusting means a, b and c, fracture reduction takes place. By periodically unlocking these adjusting means, it is also possible to provide the desired quantum of movement to the broken hand.
This invention, though illustrated herein above with a particular embodiment includes obvious equivalents known to persons skilled in the art within the scope and ambit of the appended claims.

We Claim:
1. A dynamic external wrist fixator comprising a wrist frame consisting of at least two members interconnected by hinge means, each of the said members having mounted thereon, at least one longitudinally displaceable pin gripping unit the free end of the first member being provided with a tensioning means for controlling the longitudinal movement of the pin gripping unit mounted thereon and the said hinge means consisting of three way adjusting and fastening means for controlling multiplanar ligamentotaxis of the wrist.
2. The dynamic external wrist fixator as claimed in claim 1, wherein the two members constituting the wrist frame are rods, provided with openings for housing the said pin gripping units in a longitudinally displaceable manner.
3. The dynamic external wrist fixator as claimed in claims 1 and 2 wherein the pin gripping means have sleeves for drilling pins therethrough.
4. The dynamic external wrist fixator as claimed in any of the
preceding claims wherein the tensioning means is a threaded nut
and screw assembly.

5. The dynamic external wrist fixator as claimed in any of the preceding claims wherein the hinge means has an adjusting and , fastening means oppositely disposed to the tensioning means for controlling the longitudinal axis by rotation.
6. The dynamic external wrist fixator as claimed in any of the preceding claims wherein the hinge means has a centrally located nut and screw assembly for controlling the radial and lunar deviation.
7. The dynamic external wrist fixator as claimed in claims 1 to 6, wherein an adjusting and fastening means such as a threaded nut and screw assembly is located lateraly on the second member of the wrist frame for controlling plalmar and dorsi flexion.
8. A dynamic external wrist fixator substantially as herein
described, with particular reference to the accompanying
drawings.

Documents:

0914-mas-1997 abstract-duplicate.jpg

0914-mas-1997 abstract-duplicate.pdf

0914-mas-1997 claims-duplicate.pdf

0914-mas-1997 description (complete)-duplicate.pdf

0914-mas-1997 drawings-duplicate.pdf

914-mas-1997 abstract.pdf

914-mas-1997 claims.pdf

914-mas-1997 correspondence others.pdf

914-mas-1997 correspondence po.pdf

914-mas-1997 description (complete).pdf

914-mas-1997 drawing.pdf

914-mas-1997 form-1.pdf

914-mas-1997 form-19.pdf

914-mas-1997 form-26.pdf

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Patent Number

196326

Indian Patent Application Number

914/MAS/1997

PG Journal Number

27/2006

Publication Date

07-Jul-2006

Grant Date

27-Apr-2006

Date of Filing

30-Apr-1997

Name of Patentee

M/S. CALICUT REGIONAL ENGINEERING COLLEGE

Applicant Address

KOZHIKODE 670 601

Inventors:

#	Inventor's Name	Inventor's Address
1	DR. DEVDAS MENON	PARIJATH 19/1022, TALI EAST, KOZHIKODE 673 002
2	MADAYI PUTHIYAVEETIL CHANDRASEKHARAN	ASWATHI 33/2254 VELLIMADUKUNNU KOZHIKODE 673 012

PCT International Classification Number

A61B 17/56

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA