Bone nail for the treatment of fractures of the proximal part of the femur, and the appropriate tools.

The invention relates to a bone nail for the treatment of fractures of the proximal femoral region, with a lying on the outside of the femoral condyles distal end portion having a coupling portion for engagement with a driving tool, an arcuate portion between the ends and one in the proximal femur imprisoned proximal end portion.

Such a nail is known (DE-PS 23 41 439 or DE-GM 7,218,224). It is usually along with several uses (bundle nailing). The individual is made of metal bone pins are provided with a diameter that they are resilient from reaching, so that they can be driven through a window in the condyles of the femur into the bone canal of the femur. The proximal end of the nail is seeking passage through the bone canal and passes through the femoral neck into the femoral head. The distal end of the nail is designed such that it is engageable with a driving tool to engage. With the help of the driving tool of the bone nail is driven under observation in an image intensifier in the bone channel, in particular the first nail must be rotated to reposition the bone fragment more or less. The force application of the driving tool at the distal end of the nail must therefore able to transfer considerable torques to the nail.

The known bone nails are associated with some disadvantages. The oriented transversely to the plane of curvature flattened at the distal end which are a turning tool also provided with a hole in order to effectively attack, can act as chisels, if they are not completely flat on the bone and parallel to this. The thus formed relatively sharp edges can be irritating effect on the adjacent tissue. Since the flattening are usually formed by a swaging operation, additional processing is required to thereby eliminate any burrs or sharp edges. By flattening a round nail cross section also creates a critical transition region with a relatively high stress concentration, so that it can lead to plastic deformation or even a shearing at high torques at the distal end in this area. Upon rotation of the distal ends against each other several flattened distal ends require relatively much space, whereby the patient's condition may be adversely affected.

Thus, the known bone nails can be driven in the bone canal easier, is known, these rejuvenate at the proximal end. However, results in the risk that the proximal ends emerge in the neck or in the head region and enter the hip bone or hip socket, which must be regarded as serious complication of supply method, rendering them inoperative.

The invention is therefore based on the object to provide a bone nail for the treatment of fractures of the proximal femoral region with which it is ensured that unwanted bone injuries in the area of ​​the proximal femur not occur.

This object is achieved in that the proximal end portion having a rounded bulge at the free end. When such thickeners unquestionably increases the driving-in for each nail, it may otherwise be readily accepted because avoids the renewal measure in accordance that the proximal end of the nail area at its insertion into the neck or head the femur to the femur in this area injured by penetrating or penetrating into or Cortikalis. The . greater driving-relative to that required for a peak at the proximal end, is nevertheless in a range which is acceptable in the usual surgical technique for such bone nails readily.

It will be understood that the thickening is rounded uniformly in order to avoid a violation. According to one embodiment of the invention, the thickening is a bead formed. It is preferably formed by upsetting of the proximal nail end.

The plane of curvature of the bone nail lies approximately in the plane which is spanned between the femoral shaft and femoral neck.

The introduction of force in the implanted nail is essentially parallel to the femoral shaft and thus to the proximal end of the nails, which is applied to the curved proximal end portion of a torque in the plane of curvature.

The loading of the nails is therefore largely a bending load. For this reason, a sharp proximal end has a negative effect, since only a small force attack surface is given. Also in this respect brings a bulge at the proximal end of an improvement. The force available working surface is substantially increased. In this connection, according to a further embodiment of the invention, that at the free end of the thickening is provided a flattening whose plane at an angle to the axis of the proximal nail end extends such that it is approximately perpendicular to the loading direction. This means that the flattening, achieve their surface area relative to the nail cross-section a considerable degree can, approximately perpendicular to the axis of the femur and thus also perpendicular to the loading direction.

The known bone nails sind.im circular cross section. but is largely for the demanding to the bone pins section modulus of the nail diameter in the plane of curvature crucial. That is, perpendicular to the plane of curvature can be reduced, the nail, without thereby the moment of resistance is significantly affected. With such shaped nail cross-sections can be a considerable reduction in the nail material achieve. In this regard, one embodiment of the invention, that the cross section of the nail is polygonal over its length with rounded edges. Here, however, is preferably the major axis in the^{curvature plane}, In a further embodiment of the invention it is proposed in this connection that the cross section is triangular, preferably an equilateral triangle. Also in this cross-sectional shape saves material without the resistance moment against a nail would be appreciably reduced with a similar circular cross section. Since the edges of the triangular cross-section are noticeably rounded, there is also no risk of injury in the bone canal. Furthermore, is also readily ensured that the nail can be rotated to repositioning and Eintreibzwecken. However, a triangular cross-section has the further advantage that a closer packing is possible than with a circular cross-section, so that, if necessary, more nails can be driven as a cross-sectional circular Knochennägel.Das is total resistance moment. at a given cross section of the bone canal set higher than the Rnndnägeln.

In another embodiment of the invention it is provided that the cross section is rectangular and the major axis lies in the plane of curvature. In such cross-sectional shape the material saving is even greater.

A space-saving arrangement of the distal nail ends arises when the radial extension of the distal end not on the rest of the nail goes, that is, the outer contour of the nail does not increase in the distal end.

In this context, an embodiment of the invention provides that there is provided a bore at the distal end, preferably a through-bore whose axis lies preferably in the plane of curvature. A portion of the driving tool can be brought into engagement with the bore, so that a twist can be applied to the distal end of the nail.

Alternatively, it is proposed according to a further embodiment of the invention that the distance to the distal end, a recess is formed to form a polygonal cross-section the clamping section. In the case of a polygonal cross section of the nail has a recess would not be necessary in view of the application of a rotational force. However, a recess has the advantage that also extraction forces acting on the nail can be applied.

In other Advantageous inventive embodiments of an instrument for hitting the nail invention are disclosed.

Embodiments of the invention are described with reference to drawings.

<ul><li>Fig. 1 shows a section through a femur, are implanted in the three inventive bone nails.</li><li>Fig. 2 shows a side view of the distal end of a bone nail of FIG. 1.</li><li>Fig. 3 shows a section through the bone nail of Fig. 2 taken along line 3-3.</li><li>Fig. 4 shows another profile of a bone nail according to the invention.</li><li>Fig. 5 shows another profile of a bone nail according to the invention.</li><li>Fig. 6 shows an embodiment of a proximal end of the bone nail of FIG. 1.</li><li>Fig. 7 shows a proposal device for a bone nail according to the invention.</li><li>Fig. 8 shows a section through the front portion of the - device of Fig. 7.</li><li>Fig. 9 shows a look-up device for a bone nail according to the invention.</li><li>Fig. Figure 10 shows a 90 ° rotated back end view of the device according to Fig. 9.</li><li>Fig. Figure 11 shows a front view of the device according to Fig. 9.</li><li>Fig. 12 shows a section through the device of FIG. 9 taken along line 12-12.</li><li>Fig. Figure 13 shows a cross section through another embodiment of a nail.</li></ul>

Before discussing the details shown in the drawings, was preceded by that of each of the described and illustrated characteristics is by itself or in combination with features of the claims of the invention is essential.

The three in FIG. 1 implanted in a femur 10 bone pins are generally designated 11. They are, starting from the proximal end portion provided with a continuous curvature, as shown at the 12th In the area of ​​the distal end a bend 13 is formed, followed by a straight piece fourteenth The bone pins 11 are driven via a window 15 of the medial condyle of the femur 10 shown by means of a driving tool, not shown, namely a bone nail according to the other. The first driven-in nail normally used for repositioning of the fracture segment. The insertion of the bone nails done under control with the aid of an image intensifier, so that can achieve diversification in the head region of the femur, which implies a certain rotational stability of the head is achieved relative to the rest of the femur. The proximal end portions are provided with thickenings that are generally referred to in FIG. 1 by 16.

As seen from Fig. 3, the cross-section of the nails 12 is an equilateral triangle whose corner edges are shown at 17, strongly rounded. A Page 18 forms die.konvexe side of the curve 12, while the opposite edge 19 located on the concave side of the nail 11th

As indicated by the dashed circle 20, the nail has a nail 11 opposite to the circular cross-section 20 is a significant material saving a result, without the drag torque in the plane of curvature would be much lower. The cross-sectional shape shown in Fig. 3 has the further advantage that better allow the nails in the bone canal "pack".

As further seen from Figures 2 and 3, a recess 21 is formed in the straight distal end portion 14 whose bottom 22 is approximately parallel to the side 18 of the nail eleventh With the recess 21, a driving tool can be brought into 'engagement to propel the nail in the bone tunnel or to extract it out of the bone canal, and in addition to perform a rotational movement at these movements. The remaining cross-section 23 is quite adequate to withstand rotational forces. It is recommended that in choosing the transition of the cross section 23 of the triangular solid cross-section continuously in order to avoid unnecessarily high notched forces.

It can be seen from Figures 2 and 3 that, in spite of a coupling portion for a driving tool, the outer contour of the rest of the nail will not leave, so no protruding parts are present that unnecessarily enlarge the space and affecting the tissue.

In FIG. 4, a bone pin 30 is shown in cross-section which is approximately rectangular with rounded edges also greatly 31. The plane of curvature coincides with the major axis 32 of the rectangular cross-section together. The bone nail 30 has a comparable modulus as a bone pin of circular cross-section as indicated by the dashed circle 33rd The former has therefore a significant material savings result without the carrying capacity would be less characterized.

FIG. 5 shows a nail 35, which has approximately the .Form a Maltese cross in cross-section, the edges are in turn strongly rounded as shown at 36. Here is a dashed circle 37 a circular cross section of a bone nail, whose modulus is comparable with respect to the bone nail 35th

In FIG. 6, the bone pin 11 is shown with the proximal end portion. One recognizes an enlarged diameter bead 16, whose outer contour is approximately circular. Further, the bead at the free end is flattened, as shown at 40th

The flattening lies in a plane which is approximately perpendicular to the loading direction, 'which is indicated by an arrow 41st This arrow 41 is also shown in FIG. 1.

It is understood that in addition to the section 23 can be provided with a bore or a through hole 23 'in order to improve the force engagement with a driving tool ..

A through-hole at the distal end may be formed in other at any cross-section to allow attack wrapping and extraction tool.

With 2311 in Fig. 2, a hole is indicated, which is disposed facing the outside end of the recessed portion 21. With 23 '' 'in Fig. 3 to a transversely arranged bore is designated.

The nail has in the rest of the distal end portion has a straight portion which is connected by a large sheet with the rest of the nail.

In Figs. 7 and 8, a device for bone nails proposal shown in Figs. 1 to 6 is shown. It consists of a handle portion 45 and a coupling portion 46. Both have an elongated circular cross-sectional shaft 47 which has in the handle portion 45 a transverse rod 48 which passes through a corresponding bore. In the coupling portion 46, a clutch lever 49 is pivotably mounted (Fig. 8), with the aid of a bearing pin 50. In order to accommodate the coupling lever 49 is axially formed in the shaft 47, a slot 51 which receives the relatively narrow clutch lever 49, so that it only a little beyond the outer contour of the shank 47 protrudes. The clutch lever 49 extends to the end of the shaft 47 and spans a triangular cross-section recess 52 which is open at the end of the shaft 47 and which is delimited at the opposite end by an abutment wall 53, at the foot of which a transverse groove is 54th A sunken in the shaft 47 pin 55 protrudes upward into the recess 52nd

In the bottom of the slot 51 is a blind bore 56 which receives eine'.Druckfeder 57, which 49 applied to the clutch lever clockwise. The slot 51 is provided downwardly in the diametrical direction with an opening 58 for receiving a cam 59.eines clamping lever 60th

The clamping lever 60 is pivotally mounted in the region 61 of the cam 59 with the aid of a bearing pin, the levers 49 and 60 are pivotally approximately in the same plane. A central portion of the lever 60 is received in a recess 62 of the shaft 47 partially. A handle 63 extends obliquely outwards.

In the position shown in Fig. 8, the clutch lever 49 is locked by the clamping lever 60. The highest point of the cam 59 is opposite to the rotational axis of the pin 61 offset from the pivot pin 50 toward. The spring 57 tries to rotate the clutch lever 49 in the clockwise direction. This pushes the 8 right in Fig. Part of the lever 49 on the cam 59 from above and applied den.Klemmhebel 60 counter-clockwise. However, a pivoting of the clamping lever 60 in this direction is not possible, since it is limited by the shaft 57 and the recess 62nd Only when the handle is gripped by hand 63 and the clamping lever 60 is also rotated in the clockwise direction, the clutch lever 59 can also pivot clockwise. This allows the distal end of a bone nail to be inserted into the recess 42, wherein the pin engages in the recess 55, for example, 21 of a bone nail according to FIGS. 1 to 3. Such a recorded bone nail can now be taken using the proposed tool of Figs. 7 and 8 and manipulated in a desired manner, for example, again be wholly or partially withdrawn. Inadvertent release of the device from the bone nail is prevented by the described clamping device.

Since it is difficult, especially in a plurality of nails to collect by means of a proposal device according to FIGS. 7 and 8 the bone nail to the entirety, a look-up device according to FIGS. 9 to 12 is provided. The look-up unit has an elongate shaft 65 of approximately circular cross-section which is bent in the region of the anterior third at 66 bit. The shaft 66 tapers toward the front end steadily. At its front end, it has an open forward recess 67 whose cross section is matched to the cross-section of the distal end, that is for example triangular, as in Fig. 11. The actual handle portion has a longitudinal ribbing 68, so that the look-up unit by hand can be better detected. In the back of an open outward transverse slot is formed in the shaft 69 65th Further, in parallel, a through hole 70 is provided (Fig. 10). The slot 69 has a width or the through bore 70 has a diameter which is slightly larger than the largest diameter of the bone nail. The apparatus of Figs. 9 to 12 can therefore also als.sog. Bending Iron serve, by means of which it is possible to deform the bone nail in a limited manner, ie for example to give a different curvature or direction. Preferably two such devices are being introduced.

The tip of the lookup unit can have at the bottom of a chamfer or flattened, so that they can intervene to rash purposes in the groove 21 of the nail 11th In this way, the implanted nail can be so far turned down until the proposed device can be used.

Although the profile of the nail 80 of FIG. 13 is also generally triangular as in Figures 1 to 3. The convex side 81, however, is not straight, but convex in cross-section. The relatively large radius of side 81 provides a smooth transition to the radii at the edges of the nail 80. The concave edge 82 is provided with a radius.