US2526959A - Fracture reduction apparatus - Google Patents

Description

Qct. 24, 1950 F. A. LORENZO FRACTURE REDUCTION APPARATUS Filed July 1, 19474 ZNVENTOR;

FRANK A. LORENZO Patented Oct. 24, 1950 2,526,959 FRACTURE REDUCTION APPARATUS Frank A. Lorenzo, Punxsutawney, Pa.

Application July 1, 1947, Serial No. 758,370

6 Claims.

My invention relates to the reduction of bone fractures and more particularly to an improved apparatus for use in the reduction and immobilization of hip fractures.

In Patent 2,242,003, issued to me May 13, 1941, there is disclosed method and apparatus for eduction of fracture of th femur wherein the bone elements adjacent the fracture are temporarily supported and inhibited against rotative movement prior to and during insertion of the means used for fixation of the fracture. In accordance with the aforementioned patent, the bone elements adjacent the fracture are supported and maintained in desired position by means of -a threaded bolt member, constructed and arranged to function as an auxiliary core, internally of the neck of the femur, the threaded portion of the bolt having bearin engagement throughout a substantial area of the head and upper shaft in the region of the trochanter, whereby considerable force may be exerted axially of the neck of the femur to draw the parts together. While the arrangement disclosed in my prior patent has proved eminently satisfactory for use in the reduction and immobilization of fracture of the neck of the femur, I have found, after'considerable research and experimentation, together with practicable applications of the device, that improved results are obtained by-modification of the apparatus of the patent, including the addition of intertrochanteric and sub-trochanteric support means, and a lock device to prevent the bolt from becoming loose.

The case histories of certain of the reductions, wherein my prior device was used, indicate that in order to minimize the possibility of the bolt breaking, due to the patients weight, it is desirable to provide a bolt or lag screw of maximum strength, consistent with the required length of the threaded portion, depth of threads and the sharpness thereof. In some cases it has been found that after the patient is able to walk there is a tendency for the lag screw to become loose, that is to say, movement of the parts incident to walking, tends to cause the screw to back away from its normal operative seated position. Accordingly, to prevent accidental reverse movement of the screw, it is highly desirable that locking means be provided. Study of a number of cases of hip fracture also indicates the need for intertrochanteric and sub-trochanteric bone support means adapted for use in conjunction with the cannulated lag screw.

The femur or thigh bone is formed at its upper end with a rounded head joined to the shaft of the bone by a constricted neck, the base portion of which lies adjacent two projections or eminences'called the greater and lesser trochanters.

While fractures of the femur usually occur in the restricted portion between the rounded head and the area defined by the trochanters, they sometimes occur in the intertrochantel'ic area, and in the shaft or sub-trochanteric area.

In accordance with the present invention, I have provided improved apparatus for use in the reduction and immobilization of fracturesof the femur, wherein the cannulated lag screw used for fixation of the fracture is designed to minimize the possibility of breakage when subjected to sudden jars, thrusts, and the like, or by reason of the bearing weight of the patient thereon; intertrochanteric and sub-trochanteric support is obtained by means of a plate designed for attachment to the bone in cooperative relationship with the head portion of the lag screw, and a positive lock device, associated with the plate and the head of the lag screw, is used to prevent accidental displacement of the screw.

An object of my invention is to provide improved means for use in the reduction and immobilization of hip fractures.

Another object of my invention is to provide improved means for use in the reduction andimmobilization of fractures of a femur.

Yet another object of my invention is to provide improved means adapted to be positioned interiorly of the neck of the femur and arranged ,to afford maximum support for the bone elements adj acent the fracture.

Still another object of my invention is to provide an improved cannulated lag screw adapted for use in the reduction of fracture of a femur.

A further object of my invention is to provide apparatus for use in the reduction and immobilization of fracture of a femur, having improved intertrochanteric and sub-trochanteric support means associated therewith.

Yet a further object of my invention i to provide an improved sub-trochanteric bone plate. I.

A still further object of my invention is to provide a hip fracture reduction apparatus having an improved lock device adapted. to prevent accidental loosing of the cannulated screw used for fixation of the fracture. v l

With these and other objects in view, which may be incident to my improvements, the invention consists in the parts and combinationsto be hereinafter set forth and claimed, with the understanding that the several necessary elements, comprising my invention, may be varied in construction, proportions and arrangements, without departing from the spirit and scope of the appended claims.

In order to make my invention more clearly understood, I have shown in the accompanying drawing means for carrying the same into practransverse of the neck, or in a plane at a dif tical effect, without limitin the improvements in their useful applications to the particular constructions, which for the purpose of explanation, have been made the subject of illustration.

In the drawings:

Figure l is a sectional view of a fractured femur, immobilized by means of the fracture reduction apparatus of the present invention.

Fig. 2 is 9, sectional view of a fractured femur, immobilized by a modified form of fracture reduction apparatus.

Fig. 3 is a front elevational view of the subtrochanteric Plate and lag screw locking means, shown in Fig. 1.

Fig. 4 is a front elevational view of a sub-trochanteric plate having a modified form of lag screw locking means.

Fig. 5 is a sectional view along line C-5 of Fig. 4.

Fig. 6 is a perspective view of the lag screw shown in Fi 2.

Fig. '7 is a fragmentary sectional view along line "l--'! of Fig. 1.

Fig. 8 is a top View of the head of the lag screw shown in Fig. 6; and

Fig. 9 is a fragmentary front elevational view of the head of the sub-trochanteric plate.

Referring to the drawings and more particular 1y to Fig. 1, the apparatus adapted for use in the reduction and immobilization of fracture of the femur comprises a, cannulated lag screw, designated generally by numeral I, having a body portion formed with a head member 2 and a re duced end portion 3. The body of the screw, between the head and tapered end. is formed with a threaded portion, the individual threads 4 being cut so that the edges or crests 5 thereof, are comparatively thin and sharp.

The upper portion of the femur comprises a 'rounded head 6, a restricted portion or neck I, the base 8 of which lies adjacent the greater and lesser trochanters 9 and 15, respectively, a shaft 1 I, having a lower end, not shown, adapted to articulate with the tibia and patella. As hereinbefore indicated, fractures of the femur usually occur in the restricted portion or neck I, for example, as at l2 in a plane substantially rent angle to the axis of the neck. Fractures may also occur in the intertrochanteric and sub-trochanteric areas as at l3 and l l, respectively.

The above described lag screw forms part of the required fixation and support means; tional means, comprising a sub-trochanteric bone plate, adapted for use in conjunction with the lag screw, is also provided. The plate, designated generally by numeral 55, comprises a shank portion 18, and an enlarged head ll, haying a substantially elliptical shaped opening 18, for the passage of the lag screw i therethrough. The shank portion [6 of the plate is formed with a plurality of apertures l8, for the passage of suitable securing means therethrough, the

apertures being bored so that the heads 2! of the securing means may counter-sink therein. With reference to the formation of head ll, it will be noted that it is deflected outwardly from the plane of the axis of the shank l6, and that opening [8 is formed with a peripheral recessed portion 22, (Fig. 5), providing a seat for the tapered portion 23 of the lag screw, when the screw is turned to the operative fixation position. In addition to apertures IS, the plate is provided with an elongated slot 24, for the passage of a pin member 25', and it is also tapped as at 26 (Fig. 5), between the head and the slot, to receive securing means 2?, the purpose and functions of which will be described more fully hereinafter. In order to reduce the weight of the plate, without sacrificing strength required for proper support, the shank thereof may be scalloped as at [5.

It will thus be seen, from the description of the apparatus so far, that the elements of the femur adjacent the fractures are immobilized and adequately supported by means of the lag screw and the sub-trochanteric plate. In order to prevent accidental reverse movement of the lag screw, occasioned by walking or other cause, lock means associated with the plate, and adaptedto embrace the head of the lag screw, are provided.

Referring to Fig. 3, the lock means comprises a disc or plate 28, of substantially the same configuration as the enlarged head ll of the subtrochanteric plate, having an opening 29 therein adapted to receive the head of the screw 2. The opening is formed with straight sides 30 and curved ends 3|, conforming with the shape of the reduced end portion of the lag screw, the fiat faces 32 of which abut or lie contiguous to the sides 30 when the head of the screw is seated in the opening 29. The disc is also provided with an aperture 33 for the passage of fastening means 2'! therethrough.

By means of the above-described arrangement, the lag screw is locked in operative fixation position. By reason of the fact that the disc is constructed and arranged to embrace the head of the screw, and is attached to the sub-trachanteric plate, accidental reverse movement of the screw is positively prevented. Accordingly, it will be observed that the improved locking means of the present invention is in sharp contra-distinction to devices wherein frictional engagement between the fixation means and other elements is relied upon to prevent reverse movement.

It will be readily appreciated that in addition to operative skill, reduction and immobilization of fractures of a femur, of the character illustrated, requires the use of apparatus of a nature to provide positive fixation and support, with minimum discomfort to the patient. When it is desired to reduce a fracture of a femur, in acc0rdance with the present invention, the bone elements adjacent the fracture or fractures, are positioned in correct anatomical relationship and a passage is bored through the upper portion of the shaft H, substantially centrally of the neck I, the passage terminating in the rounded head 6. The pin member 25, is then inserted into the passage thus bored, and the elements of the bone are examined, as by X-ray, to determine whether or not they are in desired position. If the inclination of the bore is found to be in proper direction, relative to the head and neck a second passage approximately parallel to said first passage is bored through the upper shaft and neck, the second passage also terminating in the rounded head. A pin member 25', similar to pin 25 is then inserted in this passage, as shown.

After the pins 25 and 25 have been placed in seated position, the diameter of the passage which accommodates pin 25 is increased, using a reamer provided with an axial passage of suificient diameter to permit pin 25 to pass freely there-through. It will be noted that reaming is effected while pin 25 is in position, and that pin 25 cooperates with pin 25' to inhibit or prevent rotative movement of the head with respect to the neck, during the reaming operation. The cannulated lag screw I, after first being inserted through opening H3 in thesub-trochanteric plate, is thereafterwards introducedinto the opening of the enlarged passage, the end of the pin 25 externally of the shaft being inserted in the passage formed axially of'the screw. Rotation of the lag screw may be effected by means of a suitable wrench or other tool adapted to engage with the flat faces 32 of the head member 2, the lag screw being advanced so that the tapered head portion 23 thereof seats in the openirig'lfi of plate It will be understood that during advancement of the lag screw, and particularly prior to the time the head becomes fully seated in opening I8, that the sub-trochanteric plate is manipulated to bring it into alignment with the shaft ll, so that its concave bone contacting surface 34 (Fig. '7), rests against the bone in desired position. At the later stages of the positioning of the lag screw and plate, as above described, the end of pin 25 is passed through the elongated slot 24 of the plate.

The lag screw having been advanced so that the head is seatedv in the opening of the plate, the reduced end 3 of the screw is then well within the compact bone area of the head 6, and further rotation of the screw causes the head to be drawn axially of the neck 1, whereby the bone elements adjacent the fractures are forced tightly together and maintained in fixed position. It will be noted that during the above described operations, pins 25 and 25' are seated in their respective passages and rotative movement of the head with respect to the neck, and/or between adjacent elements, is thus prevented.

When the lag screw is in seated position, that is, after it has been turned down so.that the parts are drawn tightly together, the plate I5 secured to shaft H by means of the screws 20 which are of such length to pass completely through the bone. Finally, the lag screw is locked against accidental reverse movementby applying disc 23 to the head of thescrew, with the straight sides iii! of the disc adjacent the flat faces 32 ofthe reduced head portion, and securing the disc to the plate by means of the screw 27, threadable through the plate and into. the opposite side of the cortex of the femur.

By reason of the design ofthe threads 4 of the lag screw, and more particularly due to the spacing, pitch and formation of the crestslof the threads which are thin and sharp, considerable force can be exerted axially of the neck of the femur to pull the bone elements together, since the threads have considerable contact area throughout the bone. The material from which the lag screw, sub-trochanteric plate, locking disc and the various securing means is made, should be of a non-corrosive character because of the natureof the environment in which they are used.

tion and electrolysis, and have considerable strength. A chromium-nickle-molybdenum steel,

for example, 18% chromium, 8% nickle and 2.3%

In addition .to being non-corrosive; the material should be ductile, free from oxida molybdenum, is particularly well adapted for use,,-

in making the parts of the fracture reduction apparatus since this material possesses all of the above desirable required characteristics.- Other alloys of stainless steel may be used, provided that they meet the above noted requirements.

Concerning the construction and arrangement I bearing support. Y The sub-trochanteric' bone plate (Fig. 2) 1 is 6 of the sub-trochanteric plate, the opening therein adapted for the passage of the lag screw is of oval or elliptical shape in order that the lag screw can be introduced into the fractured neck in valgus position. This design assists in maintaining a natural position for the lag screw, since the angularity of the neck of the femur of different patients exhibits wide variation. It is to be particularly noted that the head of the lag screw is of such configuration to provide a snug fit with the opening of the sub-trochanteric plate, and

that due to the depth of the grooves between the threads, the body portion of the screw is of substantial thickness, whereby to materially strengthen its weight bearing properties.

Referring to Fig. 2, the fracture reduction apparatus shown therein is similar to the arrangement of Fig. 1, but differs therefrom in the design of the lag screw and sub-trochanteric plate. When fractures occur in the neck, intertrochanteric area and sub-trochanteric area, as at 34, 35 and 36, respectively, a modified form of apparatus may be used. In the arrangement shown, the lag screw designated generally by numeral I, is provided with threads 4, for a portion of its length, the body 3'! of the screw between the head 2 and the threaded portion being smooth and of increased diameter, thus providing increased bearing support axially of the neck of the femur. It has been found that a lag screw of this type, that is, a threaded portion for entry into the compact bone area of the head of the femur and a smooth body portion of substantial length between the head of the screw and the threaded portion thereof, enables the head to be drawn axially of the neck and provides desired similar to the plate [5 of Fig. 1, however, it is of increased length, in order to provide support for the bone elements adjacentthe fracture 36, in the shaft of the femur. It will be understood that plates of different lengths and lag screws having various combinations of threaded and smooth portions may be used, depending upon the seat of the fracture, that is to say, whether the frac- V ture is trochanteric, .intertrochanteri'c, sub-trochanteric and/or in the neckof the femur.

Referring to Figs-4 and 5, a modified form of locking device for the lag screw is'shown. In this arrangement, the disc 28, is attached to the plate [5 by means of a member 38, having inturned projections or arms 39 arranged in overhanging relationship with the front surface of the subtrochanteric plate. The body portion 40 of member 38, adjacent the bone contacting surface of the plate, is of concave shape to conform with the concaved portion of the plate, and is provided with a tapped aperture 4 I, for the passage of the securing means 2! therethrough. In assembling the device, the lower end of plate 15 is inserted between the overhanging arms 39 and the body portion 40, and member 38 raised to th vicinity of the elongated slot 24 of the plate. The securing means is then passed through the opening in the bottom of the disc, slot 24, and threaded into the body portion of member 38, at the rear of the plate.

It will thus be seen that member 38 is designed for sliding movement longitudinally of the shank of the plate, and that adjustment of the disc into locking position with the head of the lag screw may be quickly and easily accomplished'by manipulating the disc, prior to the time securing means 2! is turned to operative seated'position in the bone shaft.

It will thus be appreciated that I have Provided improved apparatus for reducing fractures of the femur, wherein the construction and arrangement of the lag screw and the sub-trochanteric plate is in the nature of a three-point suspension which provides the type of support necessary for complete immobilization and support at the seat of the fracture or fractures.

While I have shown and described the preferred embodiment of my invention, I wish it to be understood that I do not confine myself to the precise details of construction herein set forth, by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention or exceeding the scope of the appended claims.

I claim:

1. A sub-trochanteric bone plate adapted to be secured to the femur, comprising a shank portion and an enlarged head, said shank having a concave bone contacting surface, said head being deflected outwardly from the plane of the shank portion and having an oval shaped opening for the passage of securing means therethrough, said opening having a tapered peripheral portion forming a seat for the free end of the securing means, when said means is in operative fixation position, the shank portion of the plate being apertured for the passage of other securing means therethrough.

2. A device of the character described for use in the reduction and immobilization of fracture of the femur, comprising a cannulated lag screw having a body portion formed with a head member and a reduced end portion, a plurality of relatively deep threads formed in the body portion of the screw between the head and end portion, said threads having thin sharp crests, the head portion adjacent the body of the screw being tapered, an intertrochanteric bone plate adapted to be secured to the femur, said plate having an oval-shaped opening in the vicinity of one end thereof, said opening having a complementary tapered peripheral portion to receive the tapered portion of the head of the screw, when said screw is turned to operative fixation position, and means attached to the plate adapted to engage the head of the screw, whereby to lock the screw in the operative position.

3. In a hip fracture reducticn device of the character described, a lag screw comprising a body portion having a passage longitudinally thereof, said body being formed with a head member and a reduced end portion, a plurality of relatively deep threads formed in the body between the head and end portion, said threads having thin sharp crests, the head portion adjacent the body of the screw being tapered, the free end portion of the head having reduced flat faces at diametrically opposite points thereof, a sub-trochanteric bone plate adapted to be secured to the femur, said plate having an oval-shaped opening in the vicinity of one end thereof, said opening having a complementary tapered peripheral portion to receive the tapered portion of the head of the screw, when said screw is turned to operative fixation position, and means attached to the plate adapted to engage the flat faces of the head of the screw whereby to lock the screw in the operative position.

4. A device of the character described for use in the reduction and immobilization of fracture of the femur, comprising a cannulated lag screw having a body portion formed with a head member and a reduced end portion, a plurality of relatively deep threads found in the body portion of the screw between the head and end portion, said threads having thin sharp crests, the head 5 portion adjacent the body of the screw being tapered, a sub-trochanteric bone plate adapted to be secured to the femur, said plate comprising a shank portion and an enlarged head, said head being deflected outwardly from the plane of the shank portion and having an oval shaped opening therein, said opening having a tapered peripheral portion to receive the tapered head of the screw, when said screw is turned to operative fixation position, and means attached to the plate adapted to embrace the head of the screw,

whereby to lock the screw in the operative position.

5. A device of the character described for use in the reduction and immobilization of fracture of the femur, comprising a cannulated lag screw having a body portion formed with a head member and a reduced end portion, a plurality of relatively deep threads formed in the body portion of the screw between the head and end portion, the head portion adjacent the body of the screw being tapered, said head portion having reduced fiat faces at diametrically opposite points thereof and a curved surface adjacent opposite ends of the faces, a subtrochanteric bone plate adapted to be secured to the femur, said plate having an opening in the vicinity of one end for the passage of the lag screw therethrough, said opening having a tapered peripheral portion to receive the head of the screw, when said screw is turned to operative fixation position, and means attached to the plate to lock the screw in the operative position comprising a" disc having an aperature of the same peripheral configuration as the head of the screw, adapted to embrace the head of the screw, when said screw is turned to the operative fixation position.

6. In a femur fracture reduction apparatus of the character described, a lag screw comprising a body portion having a passage longitudinally thereof, said body being formed with a head member and a reduced end portion, a plurality of relatively deep threads formed in the body between the head and end portion, said threads having thin sharp crests, the head portion adja- 50 cent the body of the screw being tapered, the free end portion of the head having reduced flat faces at diametrically opposite points thereof, a subtrochanteric bone plate adapted to be secured to the femur, said plate having an opening in the vicinity of one end thereof, the opening having a complementary tapered peripheral portion to receive the tapered portion of the head of the screw, when said screw is turned to operative fixation position, and means attached to the plate to lock 60 the screw in the operative position comprising a disc having an aperture of the same peripheral configuration as the head of the screw, adapted to embrace the head of the screw, when said screw is turned to the operative fixation position.

FRANK A. LORENZO.

REFERENCES CITED The following references are of record in the 0 file of this patent:

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