This invention relates to a plate for connecting bone fragments, in particular base splinters with bone shafts.
Nowadays, in orthopedic surgery there is a tendency to ensue, apart from connection of bone spinters, a firm internal stabilization thereof and to eliminate, in this way, a stiff dressing. This is a therapeutic method called stable osteosynthesis. One of variants of this therapy is connection of bone splinters by means of plates with holes and bone screws.
Those skilled in this field of art are aware of means providing for a compressive connection of bones consisting of a thrust plate screwed onto the bone by means of or screws with a cortex thread, with a head in the form of a shoulder, or a shaped screw nut, which is associated with a necessary operative cut indispensable for a positioning of the fracture. In the case of some fracture of humerus, elbow osteosynthesis of humerus, fracture of upper tibia and some other lesions in the vicinity of the connection, special T shaped plates are used. A common feature of the known plates is a widened fixing part which has two, or more round hole, Hole axes are either parallel, or inclined at certain angle to one another. The fixing part is provided with several round holes, or a combination of round and oval holes.
During the first stage of the operation the fixing arms of the plate are fixed by means of screws to the bone splinters. Next, the shaft portion of the plate is fastened to the bone. If necessary, before fixing the shaft portion, the bone splinters are pressed axially to each other by means of a clamping device, or an automatic compression is used.
The design of the plate and screws so far used has not made possible stiffening of the fracture in the form of a stabilizer. In order to obtain a good stabilization of the spinters one must press the plate with a considerable force against the bone by means of screws. Such a pressure of the plate against the bone, together with isolation of a large bone area by the plate from the surrounding tissues either worsens, or completely precludes revascularization of the cortex layer lying under the plate. This has been confirmed by numerous histopathologic examinations of bone splinters taken from under the plate during removal of connecting material.