US 3547114 A
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United States Patent zm'nn T em N 171mm! OTHER REFERENCES Fracture Equipment by Zimmer, Zimmer Catalog, Zimmer Mfg. Co., Warsaw Indiana, Feb. 1, 1947, Vitallium Screws, page 37. Copy available in Group 335.128/92B Combination Smoplates, Zimmer Mfg. Col Catalog, Warsaw, Indiana, page 124, picture No. 339, 1950, received in Group 335 Mar. 23, 1954.
Primary ExaminerRichard A. Gaudet Assistant Examiner-Ronald L. Frinks Attorney-Jacobs & Jacobs ABSTRACT: Fractured bones subject to compressive and tensile forces are provided with compensating plate means attached to the fractured bone and extending across the site of the fracture to hasten fusion of the fractured joint. The compensating means may take the form of a plate one end of which is fixedly secured to the bone above or on one side of the fracture site and the other end of which permits, due to a special type of connection, relative limited bone movement below or on the other side of the fracture site to take care of compressive and tensile forces acting on the bone. In a modified form of the invention, two relatively slidable plate sections, one of which has an enlarged hollow casing, are provided which can telescope under the influence of the compressive forces.
COMPENSATING PLATE MEANS FOR BONE FRACTURES The present invention relates to compensating plate means especially adapted to be applied to fractured bones and which is so constructed and designed that compressive or tensile forces acting on the fractured bone are automatically compensated for. Bone misalignment or separation is prevented and fusion of any of the major joints of the body is hastened. The invention is useful for any fractured bone where application of the compensating plate means is surgically or mechanically possible or for medical demonstration or educational purposes.
In the accompanying drawing:
FIG. 1 is an elevational perspective view of a part of a fractured bone with the preferred form of the invention applied thereto;
FIG. 2 is a fragmentary sectional view taken along line 2-2 of FIG. I;
FIG. 3 is a face view of the toothed or serrated disc element of FIG. 2;
FIG. 4 is a view similar to FIG. 1 wherein a modified form of the invention is used;
FIG. 5 is in part a sectional view taken on line 5-5 of FIG. 4; and
FIG. 6 is a sectional view taken on line 6-6 of FIG. 5.
Referring to the preferred and best mode of carrying out the invention as shown in FIGS. 13, the numeral 10 designates portions or fragments of a bone which has been fractured, the site of the fracture being indicated at 11. The arrows 12 show the direction of compressive axial forces acting on the fractured bone by the weight of or during movements of the patient. A plate- 13, preferably of elongated rectangular shape and of a suitable thickness and material, is permanently secured at one end to that portion of the bone 10 which is above or on one side of the fracture site 11 and this can be carried out by any suitable fastening instrumentalities such as the screws 14, which are preferably flat-headed and which may optionally be countersunk.
It will be seen that plate 13 also extends below or to the other side of the fracture site 11 of bone 10 and is provided with an elongated or oval slot or aperture 15 surrounded, on the surface of the plate, by ratchet teeth or serrations l6 and through such slot or aperture 15 a spring washer screw I7 (Belleville spring washer) is adapted to be passed and screwed into the bone while still, however, enabling the lower portion of bone 10 below the fracture site a certain limited and controlled amount of vertical movement depending upon the length of the opening 15 and the compressive or tensile forces acting on the fractured bone at any given instant. Spring washer screw 17 has shank 17' extending into bone fragment 10, a disc 17" having teeth or serrations 17"" and a spring washer 17" all arranged as shown in FIG. 2. Only one such screw with ratchet and slot is required. The other screws 17 afford added stability without interfering with the action of the screw with ratchet and slot.
The plate 13 can be composed of stainless steel or other metal or alloy, synthetic plastic or any physiologically acceptable, sterilizable material having requisite strength and rigidity and its exact shape, length, width and thickness depend upon the particular bone or joint and its size and the location of the fracture site. It will thus be seen that in a safe, simple and effective manner compressive forces on bone 10 push the bone fragments together and keeps them aligned whereas if the fracture site collapses the mating ratchet teeth allow the fragments to move closer but restrain extension due to tensile force.
In the modified form of the invention illustrated in FIGS. 4- -6, the portion of the bone 10 above the fracture site 11 is provided with a plate 13a similar to the upper portion of plate 13 ,and similarly provided with securing screws 14a, but the plate 130 is relatively short in length as will be observed and at its lower end flares out into a hollow casing 18 which is smooth on its external surface, but which is provided with inclined notches (cam surfaces) 19 on its inner surface. The
remainder of the compensating plate means of this form of the invention is made up of a separate lower plate 20 permanently secured as by screws 14a to a portion of bone I0 below the fracture site 11 and this lower plate 20, as will be best seen from FIG. 5, extends upwardly into the cavity 2] within the hollow casing 18 and can move in a guided controlled manner vertically upwardly and downwardly with relation to casing 18. In addition, ball bearings 22 are located in the spaces formed between the cam surfaces 19 and the adjacent surface or edge of lower plate 20 and due to the construction of the cam surfaces and the shoulders 23 thereof together with the inclination of the bottom of the notches, acts to limit the vertical up and down movement of lower plate 20 with respect to casing 18 responsive to forces acting on the fractured bone. The dimensions and construction are such as to take care of all normal compressive or tensile forces acting on the fractured bone. This modified form of the invention while somewhat less simple in construction than the preferred form of the invention, is particularly suitable for certain types of bone fractures or fracture site locations within the judgement of the surgeon or other technician, and further depending on the particular bone which is fractured and the amount of relative movement to be expected from the portions of the bone 'on each side of the fracture.
It is further understood that parts or elements of the invention such as l5, l6 and 17 in particular are exaggerated as to size for clarity of illustration and that the drawing is not to be interpreted as setting forth scale or relative sizes. The distance R in FIG. 5 shows the range of compensation of that form of the invention. When the parts are under compression, the plate sections telescope and the overall length of the plate becomes shorter; when under tension the ball bearings and inclined notch (cam) surfaces lock the two sections to prevent extension.
l. Compensating plate means for bone fractures comprising a flat, solid, one-piece serrated plate made from physiologically acceptable material with apertures spaced therealong adapted to be placed in contact with a fractured bone across the fracture site, first means passing through some of the apertures for securing one end portion of the plate to the fractured bone on one side of the fracture site and second means passing through another aperture and adapted to be responsive to compressive and tensile forces acting on the bone for securing the other end portion of the serrated plate to the fractured bone on the other side of the fracture side, said second means having a head with an attached shank extending through said another aperture, the length of said another aperture being greater than the diameter of said shank, a serrated washer mounted around said shank having its serrations in engagement with the serrations on said plate, a spring means interposed between the undersurface of said head and in engagement with the top surface of said serrated washer, whereby relative movement between said plate and said second means is possible in response to compressive and tensile forces acting on said fractured bone.
2. Compensating plate means for bone fractures according to claim 1 wherein the firs't means includes flat-headed screws extending through the plate.
3. Compensating plate means for bone fractures according to claim 2 wherein said head and shank defines a spring washer screw and said another aperture is an elongated slot extending through the plate.