1. Field of the Invention
The present invention relates to a ring and a bone fixation system. More particularly, the present invention relates to a ring for fixing a relative position of a bone screw and a bone plate, and a bone fixation system utilizing the ring.
2. Description of the Prior Art
In prior art, for curing the bone fracture, the doctor will connect two broken bones by an operation and attach the bone plate near the broken bones. Then, the bone plate will be fixed with the bones by a bone screw passing through the threaded holes on the bone plate. Accordingly, the bone screw will press the broken bones to accelerate the healing time. Generally, the design of the fixing structure of the bone plate and the bone screw is that the bone screw can be fixed with the threaded holes of the bone plate. However, if the patient with osteoporosis fracture or crush fracture, the operation will become difficult. The bone screw only can be fixed with fixing angle, so that the bone screw may penetrate the joint and the risk is high. If the threaded holes are located below the smashed area or the area of severe osteoporosis, the inclination angle will be changed to avoid the smashed area or the area of severe osteoporosis. Thus, the difficulty of the operation will be increased. The inclination angle of the bone screw can be changed lower than 10 degrees, however, the threaded holes and the screw may be damaged. Accordingly, the bone screw will not be used again.
Take TW. patent No. M282644 for example, a scope of the said patent is to provide a fixing device structure for the bone fracture. The fixing device is capable of fixing the screw to the through hole of the bone plate in various directions or angles, so the fixing direction can be changed. Thus, the fixing position can be changed with wide range and the process of the operation will become smooth. By threaded holes with different angles, the bone screw can pass through the threaded holes to fix two broken bones. Accordingly, the fixing device structure is capable of avoiding damage and decreasing the trouble for the operator. However, Taiwan Patent No. M282644 discloses a design with the bottom side of the through hole, an adjustment slot and an angle glove with a hook-type tenon. Thus, the user shall determine the position and the direction of the pre-determined tenon and the adjustment slot, and applies a huge pressure by a tool, for letting the hook-type tenon of the angle glove be fixed in the through hole of the bone plate. Thus, jig devices or tools shall be developed. In the process, if the angle of the spiral angle of the angle glove is wrong and the user wants to remove the angle glove, the user shall use a tool to let the angle glove shrink. Accordingly, the angle glove with a hook-type tenon will be damaged easily.
To sum up, developing a fixation device for curing the bone fracture became an important issue in the field. The fixation device shall be capable of fixing the screw to the through hole of the bone plate in various directions or angles and prevent the bone screw from passing through the joint, the smashed area or the area of severe osteoporosis. Furthermore, the fixation device shall be easy to operate, capable of avoiding damage and decreasing the trouble for the operator.
A scope of the invention is to provide a ring embedded in a bone plate, for fixing a relative position of a bone screw and the bone plate. The ring has a sidewall, the sidewall has a plurality of gaps. The ring further comprises a lower holding portion and a bottom surface. The lower holding portion is located at the junction of the sidewall and a bottom surface of the ring, for holding a lower surface of the bone plate. The lower holding portion is formed by extending outward from the sidewall. The upper holding portion is located at the junction of the sidewall and a top surface of the ring, for holding an upper surface of the bone plate, wherein the upper surface is relative to the lower surface. Wherein, the lower surface is contacted with a bone, the upper surface is relative to the lower surface. Additionally, the plurality of gaps extend from the bottom surface and toward the top surface of the ring along the normal vector of the bottom surface. The plurality of gaps are formed at the sidewall in a matrix form. The ring further comprises a penetrated hole, wherein a determined angle is formed between the extension direction of the penetrated hole and the horizontal direction of the bone plate. The determined angle is larger than 100 degrees or less than 80 degrees.
Another scope of the invention is to provide a bone fixation system. The bone fixation system comprises a bone plate, a bone screw and a ring. The bone plate comprises an upper surface and a lower surface. The lower surface is contacted with the bone, the upper surface is relative to the lower surface. The lower surface comprises a lower concave structure for holding the lower holding portion of the ring. The upper surface comprises an upper concave structure, for holding the upper holding portion of the ring. The lower concave structure and the upper concave structure pass through and connect to each other by a through hole, so that the ring can be embedded in the bone plate.
Compared to prior art, the bone fixation system lets the lower holding portion pass through the through hole of the bone plate and hold the lower concave structure of the bone plate by the elastic deformation of the sidewall of the ring. Additionally, the upper holding portion holds the upper concave structure so that the ting can be embedded in the bone plate. The ring can be embedded in the bone plate by a pressure applied from a tool easily. The ring can be prevented from damaging, so that the trouble of the medical personnel can be decreased. Furthermore, the bone screw can be fixed in the hole of the ring tightly and the ring is embedded in the bone plate, so that the bone plate can be fixed in the bone by the bone screw. The fixing angle can be changed by the different rings which have different determined angles. Thus, the fixing angle can be changed and the through hole of the bone plate can be fixed in various directions or angles. Accordingly, the doctor can choose the fitting angles match with bone screw for preventing the bone screw from passing through the joint, the smashed area or the area of severe osteoporosis.
The advantage and spirit of the invention may be understood by the following recitations together with the appended drawings.
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In the embodiment, the lower concave structure 38 is formed on the lower surface 34 of the bone plate 30. The concave area of the lower concave structure 38 is larger than the area of the through hole 39, wherein the lower concave structure 38 is an elliptical slot. However, the lower concave structure 38 is not limited to the said design, the lower concave structure 38 also can be a strip of slot or a concave structure corresponds to the shape of the through hole 39. The upper concave structure 36 is formed on the upper surface 32 of the bone plate 30. The concave area is larger than the area of the through hole 39. The concave area decreases and decreases along the extension direction of the lower surface 34, and a paraboloid is formed accordingly. Wherein, the concave shape of the upper concave structure 36 on the upper surface 32 is an ellipse. However, the lower concave structure 38 is not limited to the said design, the lower concave structure also can be a concave structure corresponds to the shape of the through hole 39 or the lower concave structure 38.
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In the embodiment, the lower holding portion 18 passes through the through hole 39 and hold the lower concave structure 38 of the bone plate 30. The upper holding portion 19 holds the upper concave structure 36 of the bone plate 30.
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In practice, because of the plurality of gaps 14, the sidewall 12 has enough space to elastically deform for decreasing the resistance generated by the extrusion of the material. Additionally, because the plurality of gaps 14 divide the sidewall 12 into many intervals, the sidewall 12 can elastically deform separately and decrease the shear stress can be decreased. Furthermore, because the stress of the material can be concentrate, the resistance of the elastic deformation will be decreased and the material can be prevented from damaging. Compared to prior art, the ring can be embedded in the bone plate by a pressure applied from a tool easily and prevented from damaging. Thus, the trouble of the medical personnel can be decreased.
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In practice, the fixing angle can be changed by the different rings which have different determined angles. Thus, the fixing angle can be changed and the through hole of the bone plate can be fixed in various directions or angles. Accordingly, the doctor can choose the fitting angles match with bone screw for preventing the bone screw from passing through the joint, the smashed area or the area of severe osteoporosis.
To sum up, the bone fixation system lets the lower holding portion pass through the through hole of the bone plate and hold the lower concave structure of the bone plate by the elastic deformation of the sidewall of the ring. Additionally, the upper holding portion holds the upper concave structure so that the ting can be embedded in the bone plate. The ring can be embedded in the bone plate by a pressure applied from a tool easily. The ring can be prevented from damaging, so that the trouble of the medical personnel can be decreased. Furthermore, the bone screw can be fixed in the hole of the ring tightly and the ring is embedded in the bone plate, so that the bone plate can be fixed in the bone by the bone screw. The fixing angle can be changed by the different rings which have different determined angles. Thus, the fixing angle can be changed and the through hole of the bone plate can be fixed in various directions or angles. Accordingly, the doctor can choose the fitting angles match with bone screw for preventing the bone screw from passing through the joint, the smashed area or the area of severe osteoporosis.
With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
Number | Date | Country | Kind |
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100209435 | May 2011 | TW | national |