The invention relates to a repositioning device and a method for the treatment of distal radius fractures by means of an osteosynthesis plate.
The use of angle-stable plates is known for the treatment of fractures of the forearm distant from the body (spoke bone, radius). A problem here is to obtain an adequate repositioning of the fracture fragments. The outcome should be to restore the human anatomy before the fall.
The anatomical position in the frontal plane with an angle of 25° steepness and approx. 1-5 mm additional length with respect to the ulna at the level of the distal radioulnar joint is decisive for the distal spoke bone (radius) distant from the body. In the sagittal plane, the articular surface of the radius is tilted by approx. 10° in the palmar direction (palm of the hand side). In a typical fracture of the radius, there is a dislocation of the distal fracture fragment out of this anatomical position of around 20-50° in the direction of the back of the hand (dorsal). This dislocation has to be corrected by the treating surgeon. However, this is usually not completely successful. An angle of 0° to 5°, in many cases only a repositioning angle of 0°, is achieved with a conventional operation. In this case, the distal fracture fragment in the sagittal plane is fixed only vertical to the radius shaft.
A T-shaped osteosynthesis plate is previously known from US 2005/0065522 A1. When it is used for an osteotomy, the short leg is screwed by means of bone screws to the distal end of the bone, the subsequent fracture segment, the long leg standing away at an angle from the proximal bone near the body. The bone proximal to the distal end is then sawn off and the plate is swiveled through the angle by means of its long leg to the bone near the body and screwed to the proximal bone near the body by means of bone screws introduced through the long leg into the proximal bone near the body.
The known T-shaped osteosynthesis plate can be used not only in connection with an osteotomy, but also in connection with bone fractures, as has been described at the outset. In the case of a typical fracture of the distal radius distant from the body, the dislocation of the distal fracture fragment has to be corrected by the treating surgeon. However, this is not usually completely successful with the known T-shaped osteosynthesis plate.
The problem underlying the invention, therefore, is to improve the repositioning device and the method for the treatment of distal radius fractures by means of a T-shaped osteosynthesis plate, in such a way that the required tilting of the articular surface in the palmar direction of the employed osteosynthesis plate can be carried out with angular precision.
In order to solve this problem, the invention provides a repositioning device, wherein the lower surface of the long, proximal leg of the T-shaped plate facing the proximal bone or radius shaft is provided with a spacer in order to keep the long leg at a specific angle with respect to the proximal bone near the body.
For this purpose, the spacer beneath the long leg of the T-shaped plate is adjusted to achieve the required angle. When the long leg is then placed with its lower surface, with the interposition of the spacer, on the proximal bone near the body, the short leg of the T-shaped plate already lying with its underside on the dislocated fracture fragment, the T-shaped plate is first fixed distally with the bone screws. The long leg of the T-shaped plate does not therefore lie directly on the proximal bone, but rather stands several millimetres away. An angle between 5° and 20° thus arises between the distal fracture fragment fixed in a neutral position (neutral with respect to the shaft axis of the bone) and the T-shaped plate. If the spacer is now removed by the surgeon and the T-shaped plate is pressed with the long leg onto the proximal bone, the distal fracture fragment fastened to the T-shaped plate is tilted in the palmar direction by the angle of the previously introduced spacer. The anatomy of the distal radius is thus restored in a straightforward manner with a 10° palmar tilt in the sagittal plane, i.e. the remaining 10° tilt of the articular surface in the palmar direction is achieved again together with the T-shaped plate.
In a further embodiment of the invention, the spacer is a distancing element in the form of a wedge, cylinder or parallelepiped that can be disposed on the lower surface of the long leg facing the proximal bone near the body. These distancing elements have to be adapted in their size to the desired angle before insertion in order to achieve a specific, desired angle between the long leg and the proximal bone.
According to the invention, the wedge has an angle of 5° to 20° between its wedge surfaces resting on the proximal bone near the body and on the lower surface of the long leg facing said proximal bone. Furthermore, the wedge can be fastened detachably on the contact side of the long leg facing the proximal bone near the body. With the spacer according to the invention, in this case a wedge, an anatomical repositioning of at least approx. 15° is achieved.
In a further embodiment of the invention, the spacer or the distancing element is a distancing screw that can be screwed in the long leg, said distancing screw comprising a contact face for the proximal bone near the body. Furthermore, the distancing screw can comprise a head thread and a smooth shank. The distancing screw that can be screwed in the long leg enables easy adaptation of the angle between the long leg and the proximal bone to the requirements of the individual application.
The invention also relates to a method for the treatment of distal radius fractures by means of the T-shaped osteosynthesis plate of the repositioning device. The short, distal leg of the T-shaped plate is first screwed to the distal fracture fragment, the long, proximal leg of the T-shaped plate being held spaced apart by means of the spacer at a specific angle with respect to the proximal bone near the body, and finally after removal of the spacer the long leg of the T-shaped plate is pressed onto the proximal bone near the body and is fastened there, as a result of which the distal fracture fragment fastened to the T-shaped plate is tilted by the adjusted angle in the palmar direction.
In one form, the invention is directed to a method of treating a distal radius fracture that produces a bone fragment at a radius shaft. The method includes the steps of: obtaining: a) an osteosynthesis plate with a long, proximal leg and a short, distal leg; and b) a distancing element; fastening the short, distal leg to the bone fragment with the distancing element acting between the long, proximal leg and the radius shaft so that the distancing element maintains the long, proximal leg at a specific angle with respect to the radius shaft; removing the distancing element from between the long, proximal leg and the radius shaft; pressing the long, proximal leg towards the radius shaft to thereby reposition the bone fragment relative to the radius shaft; and fastening the long, proximal leg to the radius shaft,
In one form, the short, distal leg has an opening therein. The step of fastening the short, distal leg to the bone fragment involves directing a fastener through the opening in the short, distal leg and into the bone fragment.
In one form, the long, proximal leg has an opening therein. The step of fastening the long, proximal leg to the radius shaft involves directing a fastener through the opening in the long, proximal leg and into the radius shaft.
In one form, the long, proximal leg has a surface that engages the radius shaft with the long, proximal leg fastened to the radius shaft. The step of obtaining a distancing element involves obtaining a distancing element that is configured to maintain the surface of the long, proximal leg at an angle of 5-20° with respect to the radius shaft with the distancing element acting between the long, proximal leg and the radius shaft.
In one form, the short, distal leg has a surface that engages the bone fragment with the short, distal leg fastened to the bone fragment. The step of obtaining an osteosynthesis plate involves obtaining an osteosynthesis plate wherein the surfaces on the long, proximal leg and short, distal leg together make an obtuse angle.
In one form, the step of removing the distancing element from between the long, proximal leg and the radius shaft involves fully separating the distancing element from the osteosynthesis plate.
In one form, the distancing element and osteosynthesis plate are fully separable from each other. The method of treating a distal radius fracture further includes the step of directing a fastener through the long, proximal leg and distancing element and into the radius shaft to maintain the distancing element between the long, proximal leg and the radius shaft.
In one form, the method further includes the step of removing the fastener to allow the distancing element to be separated from the osteosynthesis plate before the long, proximal leg is fastened to the radius shaft.
In one form, the distancing element has oppositely facing surfaces that are angled with respect to each other. One of the oppositely facing surfaces engages the long, proximal leg and the other of the oppositely facing surfaces engages the radius shaft with the distancing element maintaining the long, proximal leg at the specific angle.
In one form, the step of obtaining an osteosynthesis plate involves obtaining a T-shaped osteosynthesis plate.
In one form, with the long, proximal leg fixed to the radius shaft the surface of the short, distal leg makes an angle of at least 15° with respect to the surface of the long, proximal leg.
In one form, the distancing element has oppositely facing surfaces that are substantially parallel with respect to each other. One of the oppositely facing surfaces engages the long, proximal leg and the other of the oppositely facing surfaces engages the radius shaft with the distancing element maintaining the long, proximal leg at the specific angle.
In one form, the step of obtaining a distancing element involves obtaining a distancing element that is configured to be advanced relative to the long, proximal leg and against the radius shaft to thereby selectively change the specific angle.
In one form, the step of obtaining a distancing element involves obtaining a distancing element that is threadably engaged with the long, proximal leg. The method further includes the step of turning the distancing element relative to the long, proximal leg to thereby change the specific angle.
In one form, the distancing element has a shank that is unthreaded.
In one form, the distancing element has a threaded shank.
In one form, the distancing element has a shank with a blunt free end that abuts to the radius shaft with the distancing element maintaining the long, proximal leg at the specific angle.
In one form, the method further includes the step of separating the distancing element from the long, proximal leg before fastening the long, proximal leg to the radius shaft.
In one form, the long, proximal leg has a distal end adjacent the short, distal leg and a free, proximal end. The distancing element is closer to the free proximal end than the distal end with the distancing element maintaining the long, proximal leg at the specific angle.
In one form, the step of fastening the short, distal leg involves directing a plurality of fasteners through the short, distal leg and into the bone fragment. The step of fastening the long, proximal leg involves directing a plurality of fasteners through the long, proximal leg and into the radius shaft.
The repositioning device according to the invention for the treatment of distal radius fractures by means of a T-shaped osteosynthesis plate is explained in greater detail below with the aid of several embodiments. In the figures:
This previously known repositioning takes place by means of a T-shaped osteosynthesis plate 7, in short a T-shaped plate 7, the short and long legs 12, 13 whereof are screwed according to
In order to make it easier for the surgeon to achieve the remaining 10° tilt of the articular surface in the palmar direction according to reference number 6 together with employed T-shaped plate 7, lower face 14 of long, proximal leg 13 facing the proximal bone or radius shaft 11 is provided according to the present invention with a spacer 15 in the form of a wedge 16 in order to keep long leg 13 at a specific angle γ of between 5° and 20° by means of its wedge faces. Wedge 16 can be held in particular by means of a bone screw 17, which passes through holes 18 and 19 in long leg 13 and in wedge 16 (
Spacer 15 forms a distancing element 20 disposed on lower surface 14 of long leg 13 facing proximal bone or radius shaft 11 near the body. According to
The long leg 13 having lengthwise proximal and distal ends. The spacer 15 and plate 7 are configured so that with the short leg 12 operatively fastened, the spacer 15 produces a wedging force in the plate 7 at a location closer to the proximal end than the distal end.
According to
By means of distancing screw 24 or screw pin 26 of differing length, arbitrary distances between long leg 13 of T-shaped plate 7 and proximal bone or radius shaft 11 and therefore arbitrary angles γ can be adjusted. It can thus be seen that a spacer 16 is provided as a distancing element 20, which is not necessarily a solid wedge 16, but rather other geometrical figures can also be used.
The method for the treatment of distal radius fractures by means of T-shaped osteosynthesis plate 7 of the repositioning device described above is characterised in that short, distal leg 13 of T-shaped plate 7 is rigidly screwed to distal fracture fragment 10, that long, proximal leg 13 of T-shaped plate 7 is held spaced apart by means of spacer 15 or distancing element 20 at a specific angle γ between 5° and 20° with respect to proximal bone or radius shaft 11 facing inwards towards the body and that, after removal of spacer 15 or distancing element 20, long leg 13 of T-shaped plate 7 is pressed onto proximal bone or radius shaft 11 and is fastened there by means of bone screws 8, as a result of which distal fracture fragment 10 fastened to T-shaped plate 7 is tilted by adjusted angle γ in the palmar direction according to reference number 6 (
The anatomical adaptation of T-shaped plate 7, which has an angulation or an angle δ of approx. 20° of short leg 12 of T-shaped plate 7 with respect to long leg 13, rules out the possibility of this pre-bending alone also leading automatically to a corresponding fracture repositioning. The 0° position of the articular surface is on the contrary reached with the angular T-shaped osteosynthesis plates previously known in the prior art, as has already been mentioned in the introduction. As a result of the inventive embodiment of angled T-shaped plate 7, said angulation automatically resulting from the plate pre-bending through angle δ and the use of a spacer 15 or distancing element 20, e.g. in the form of wedge 16, the fracture is “forced” into the required tilt. With the angulation of T-shaped plate 7 alone, this is only possible if T-shaped plate 7 somehow “is held in air” during the operation. This is accompanied by the risk of T-shaped plate 7 then not lying orthograde on bone shaft or radius shaft 11, but being displaced laterally. The surgeon cannot possibly bring a T-shaped plate 7 held by hand in the air subsequently up to bone or radius shaft 11 with the required precision. Moreover, a defined spacing is thus also not complied with that subsequently permits a predictable tilt of fracture fragment 10. This purely “manual” precision is not sufficient and is fundamentally changed by the repositioning device according to the invention and the method performed with said repositioning device.
T-shaped osteosynthesis plate 7 alone is not a repositioning device for the treatment of distal radius fractures, but rather a pure support plate, which is adapted by its angulation to the anatomy and is placed on a bone preset by other fixing elements such as Kirschner wires and already prefixed anatomically and, due to its angulation, does not then displace the latter again during the fixing.
There follows a comparison of the chronological sequence in the case of
A: a normal operation with a T-shaped osteosynthesis plate according to the prior art:
with
B: the chronological sequence with an osteosynthesis plate in the first embodiment of the invention with a wedge:
This comparison of the repositioning procedures according to the prior art and according to the invention shows that the chronological sequence in a normal operation agrees with the chronological sequence with the repositioning device according to the invention only in steps 1 to 3. The sequence with the use of the repositioning device according to the invention then takes, with steps 4 to 7, a different procedural route from the previously known method which then comprises steps 4 to 6.
The foregoing disclosure of specific embodiments is intended to be illustrative of the broad concepts comprehended by the invention.
Number | Date | Country | Kind |
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10 2009 030 622.6 | Jun 2009 | DE | national |
This application is a continuation of U.S. application Ser. No. 13/380,133, filed Dec. 22, 2011, which is a national stage of PCT/EP2010/058910, filed Jun. 23, 2010.
Number | Date | Country | |
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Parent | 13380133 | Dec 2011 | US |
Child | 15862090 | US |