US3530854A - Fracture nail assembly - Google Patents

Description

[lll 3,530,854

128/92 12S/92 l28/92 aude! Assistant Examiner- Ronald L. F rinks Inventor John Kearney 3,029,811 4/[962 9024 Kennedy Blvd., North Bergen, New 3,107,666 lO/l 963 Cecere et al. Jersey 07047 3,374,786 3/l968 Callender..................... 744 165 y July l l 1968 Primary Exannner Richard A. G sept' 29 1970 Attorney- Mandeville and Schweitzer FRACTURE NAIL ASSEMBLY United States Patent [2l] AppLNo.

[22] Filed [45] Patented Patentedv Sept. 2 9, 1970 INVENTOR l JOHN KEARNEY I' BY ATTORNEYS BACKGROUND oF'INvENTIoN lIVlaissie type nails and screws have been widely employed heretforeinthe fixationv ofifractured bones. A commonly used 'telescopingMassie nail includes a` hollow nail member haying'fa cyliiidrical body and a plurality of fins disposed at its forwardend and a telescoping cylindrical impacting member, the outer end of which is adapted 'to be fastened to an appropriat'eplate assembly supported on theouter surface of a femur shaft.

` As `is lstandard practice in theplacement of Massie nails,` a thin Kir'ehnerg'uide wire is first inserted into the fractured portions of the bone at an established lsubstantially optimum axis for the fixation ofl the fragments of t-he fracturedvfemur. Thereafter, the Massie nail,A which'has alongitudinal bore slightly larger than the outer diameter of lthe guide wire, is drivenint 'the bone over-the wire` in alignment withV the optimum axis. The guide wire isthen withdrawn and the protruding endof the nail may be secured to a plate affixedto the femur shaft.

`While the devices of the above described construction have been generally acceptable, irisome cases, after an extended period l`of time, the insert'ednail has manifested "a tendencyto loosen orotherwisebecome unstable with resultanrdeleterious effects.; whenthis'occurs, the removal of the nail assembly and the refixation of the fractured femur is necessitated. Accordinglynit is the primary objectief the present invention t provide an improved telescoping nail assembly which will maintain its ftrman'chora'ge andstable fixation of the fracturedfemiir indefinitely.

SUMMARY 0F INVENTION VIn accordance with the invention, the improved Smith` Peterson nail assembly includes an auxiliary, threaded, anchoring rod member which is` adaptedto substantially fill the internal bore ofthe finned, hollow nail body'member and to project beyond the periphery of the nail body into the femoral head in a manner supplementing and enhancing the anchorage of the nail. Additionally, and as an important aspect of the invention, claw-like portions are formed by extensions of' the fins. These clawlike portions extend beyond 'the forward cnd ofthe cylindrical nailbody and have substantial" or openings therebetween, which gaps permit communication between the anchoring rod and the surrounding bone tissue. Importantly, in addition to itsfunction of enhancing the anchoring of the sliding nail assembly, the auxiliary rod also serves to expel or extrude any tissue, bone fragments, or other debris that may have workedits way into the internal bore of the nail body after the Kirchner guide wire has been removed therefrom. Moreover, the rod acts as a plug or seal forl the boire to prevent the entrance of organic matter into the internal bore of the nail body. This arrangement prevents the accumulation of build up of necrotic or decayable material within the assembly which might, over an extended course of time, tend to weaken or to otherwise interfere with the anchoring ofthe nail assembly in the femoral head.

DRAWING For a more complete understanding of the present invention and a better appreciation of its attendant advantages, reference should be made `to the following detailed description taken in conjunction with the accompanying drawing, in which: p

, FIG. I is an exploded, perspective view ofthe components of atclcscopi'ng nail assembly embodying the principles of the invention; and

FIG. 2 is a cross-sectional view of the new and improved nail assembly of the invention showing its disposition in a fractured hip bone.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION Referring now to FIG. l, the new and improved telescoping nail assembly of the present invention includes three major elements, a forward or inner nail body element l0, a rearward or outer impactingmember l l, and an auxiliary anchoring rod l2. The nail body member 10` is a one-piece element, advantageously formed from stainless steel or a comparable high strength alloy by conventional manufacturing processes. Asi

shown, the nail body l0 includes a hollow cylindrical body element l3'having a uniform outer diameterfor approximately: two-thirds its length and`tapering to a substantially smaller diameter at its forwardmost end k14. The outer surfaces of ther body portion 13 of the nail include a longitudinallyiextending` keyway 18.

The forward portions of the body element l3support a plui rality of integral, laterally projecting fins 15 which, as shown, include extensions 16 which `project axially forwardly ofthe end 14 of the hollow nail body in the nature of gripping claws. Advantageously, the surfaces of the claws 16 are in the form of beveled knife edges which are rearwardly sloped,` as shown best in FIG. 2, to facilitate driving of the nail body element l0 into bone tissue B.

The impacting element-ll may be of a suitable designand advantageously is a hollow cylindrical element, as illustrated. The inner longitudinal cylindrical bore 20'of the impacter ll is adapted to f'It snugly over the cylindrical surfaces l3aof the nail body l0in a telescoping manner. As shownin FIG. 2, the impacter 11 includes an internally disposed key 23 which is adapted to cooperate with the keyway 18 to maintain the telescoping elements 10, ll ina non-rotationalengagement. Advantageously, the impacter 1I includes an integral, inwardly sprung element 2l which is arranged to provide a preuse frictional engagementbetween the bore 20 and the surface portions 13, .e., friction of approximately 14 to I8 ounces is present at all times. As will be understood, it is through the telescoping, frictional engagement of the impacter lfl and the nail body l0 that the driving forces of hammer blows applied by the surgeon to the enlarged outer end 22 of the impacter are transmitted to the nail element l0.

As shown in FIG. 2, the nail body element I0 includes an internal longitudinally extending bore 25, which has a diameter slightly greater than a Kirchner guide wire. The bore 25 extends from the forward end I4 of the cylindricalnail body portion for the major portion of the length of the nail and terminates in an enlarged, threaded bore or recess 26 at the rearward end of the nail body.

As a most important aspect of the invention, an auxiliary anchoring rod element 12 having an overall length on the order of the length of the nail body element l0 is included in the assembly. The rod 12 includes a threaded forwardend 27 terminating in a conical pointed tip 28, and an enlarged, threaded, rearwardly disposed head portion 29 which `is adapted to threadedly engage the recess 26 of the nail body l0, as will be understood. Advantageously, the pitch of the threads 27, 29 at the opposite ends of the rod l2 is the same. An appropriate screw driving slot 30 is provided at the outermost head portions of the auxiliary rod l2. I I

The anchoring rod l2, as well as the impacter device Il, is advantageously manufactured from the same material or from a mechanically strong, durable material having the same thermal coefficient of expansion as the material used for the nail element 10.

In accordance with the principles of the invention, fixation of a fractured hip bone using the new and improved telescoping nail assembly may be accomplished by a surgeon following the same general procedures currently employed in the placement of Smith-Peterson type nails. That is to say, after the optimum axis of fixation has been properly determined and a Kirchner wire has been driven into the site F of fixation along that axis, the fracture nail assembly, including the nail body element and the impacter element ll, is slipped over the Kirchner wire and'is driven into the bone along the predetermined axis by the repeated application of hammer blows to the head 22 of the impacter. As a most important aspect of the invention, after the Kirchner wire is removed and the nail element l0 is fully driven (causing a telescoping of the elements l0, ll as shown), the auxiliary rod l2 is inserted through the bore of the impacter and is fed into the bore 25 of the nail body. Thereafter and in accordance with the principles of the invention, as the auxiliary rod l2 is introduced into the bore 25, any organic matter which might have entered the bore will be expelled through the opening in the forward end 14 of the nail body by the extruding action of the auxiliary rod as it is advanced therethrough.

As a further important aspect of the invention, the auxiliary rod is so proportioned that the thread 29 will engage the threaded bore portions 26 of the nail body at approximately the same instant that the threaded anchoring portions 27 of the rod extend beyond the forwardmost body portion 14 and into the bone tissue. At this point, the surgeon can easily drive the auxiliary rod into the bone tissue lying between and beyond the claws I6 by engaging a screwdriver in the slot 30 to rotate the rod and thus to advance the threaded portions 29 within the threaded bore 26 while simultaneously advancing the threaded portions 27 within the bone tissue of the femoral head. The rod may be driven until the enlarged threaded portions 29 are bottomed in the stepped bore, as shown in FlG. 2, and the forwardmost end of the auxiliary rod extends beyond the claws 16.

As will be appreciated, the auxiliary rod l2 will substantially fill and effectively seal thc bore it will supplement and enhance the anchoring of the nail body element in the fractured hip bone; and it will expel undesired organic matter from within the bore of the nail body element. lt will be understood that the expelled matter will be assimilated or otherwise disposed of by the natural healing processes of the bone.

With the nail body element impacted and fully driven, and the assembly telescoped as shown, the fixation of the fracture may be completed by fastening the outer end 22 of the impacter in place to prevent rearward displacement. This is readily accomplished by the use of a conventional bone plate 30 (only a small portion of which is shown) which may be appropriately attached by screws 3l to the femur shaft. More specifically, the bone plate 30 includes a canted flange 32 having an opening 33 therein through which an appropriate screw or bolt 34 may be fastened to the bore of the impacter by means of suitable threads 35 provided therein.

lt should be understood that the specific telescoping nail assembly herein illustrated in connection with a fractured hip bone and described in connection with a fractured hip bone is intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.

l claim:

1. An assembly for securing bone fractures comprising:

a. an elongated nail body element of predetermined length defining an elongated internal bore extending throughout said body;

b. a plurality of laterally projecting fin means disposed about outer, forward portions of said nail body;

c. said Fin means projecting axially beyond the forward end of said body and forming claw means defining openings therebetween;

d. a hollow impacting element;

e. said nail body having portions mounting said impacting element in telescoping, frictional engagement therewith; an auxiliary rod means slightly smaller in diameter than said internal bore so as to substantially fill said internal bore;

g. said rod means including a tapered and threaded forward end and having an enlarged, threaded head portion at the opposite end thereof; 0 said elongated bore of said nail body having an enlarged,

threaded rearmost portion matingly receiving said head portion of said rod means; and

. said rod means being of sufficient length to project outwardly and beyond the forward end of said bore and between said claw means upon the threaded engagement of the head portion of said rod means with said enlarged bore portion of said nail body.

2. The assembly of claim l, in which said rod means is of predetermined length sufficient to extend beyond the ends of said claw means.

3. The assembly of claim l, in which said claw means include beveled, sloped, knife edge portions.

4. The assembly of claim l, which further includes:

a. bone plate means; and

b. fastening means detachably connecting said impacting element and said bone plate means.

5. The assembly of claim l, further characterized in that:

a. said nail body element and said impacting element are substantially cylindrical; and

b. cooperating key and keyway means prevent the rotational displacement of said impacting element arid said nail body with respect to one another.

6. The assembly of claim 5, in which:

a. said key means comprises a projection formed within the bore of said impacting element; and

b. said keyway means comprises an elongated groove formed in an external surface ofsaid nail body.

7. An assembly in accordance with claim vl, in which the threaded end portions and threaded head-portions of said rod means are of the same pitch.

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