Junction element for osteosynthesis.

p0001The invention relates to a connecting element for osteosynthesis of the specified in the preamble of claim 1..

p0002The association repositioned bone fragments is previously carried out mainly by means of screws, plates, External fixation devices, tension band and nailing.

p0003The operation of drives and external hard holders corresponds to a development or modification of the direct screw. A disadvantage of the gland repositioned bone fragments is mainly a remaining uncertainty as regards the stability of the connection. To achieve optimum stability, an accurate account of all characteristic for the respective application conditions is required. Correspondingly large the Sorti-ment is broad with screws, plates and external hard holders. Moreover, the use of plates and external hard holders placed a strain on the tissue on either side of the fracture, as each come more screws are used. Preparatory work before the insertion of the screws are very time and labor consuming.

p0004The field of application of the tension band is very limited, since the tension band is only applicable to simple fractures or offering additional security in other methods.

p0005The union of bone fragments by intramedullary nailing is also limited to certain types of fractures. A stable nailing is possible only after drilling the medullary cavity. In order to prevent movements in the fracture gap, the nail must be extremely long and thick. Nail dimensions of the order of 13 mm diameter and 300 mm length are the result. The Preparation of intramedullary nailing is no less complicated than that of the screw.

p0006The main disadvantage of all known implants for osteosynthesis Association repositioned Knochenfragmen te is that its stabilizing effect is relatively small and difficult to predict.

p0007The invention has for its object to provide a connecting element for association repositioned bone fragments, which is characterized by improved stability and minimize the impact of the surrounding tissue fracture. In addition, should they not do so reoperation.

p0008This object is solved by the characterizing features of claim 1.

p0009The invention is based on the realization that, a very intensive contact with the bone and thus a tight fit of the implant is achieved by means of a two-piece implant, said part serves for spreading the other part. In this case, the implant consists of a cylinder-like receiving part which is provided with a conical axial bore and a nail, the shank diameter is between the smallest and the largest bore diameter of the receiving part and the shank length approximately corresponds to that of the bore of the receiving part. The nail is driven after the insertion of the receiving part between the bone fragments in the conical bore of the receiving part, which - assuming low elasticity or flexibility of the receiving part - wedging between the receiving part and the surrounding bone tissue caused. By reabsorbing degradation of the implant and replacement by bone tissue whose subsequent surgical removal is unnecessary.

p0010This effect is enhanced in accordance with an advantageous development of the invention by slitting the wall of the receiving part in the area approximate agreement of the diameter of the tapered hole and the nail diameter. In this way, a spreading apart of a certain part, preferably the distal end reach of the receiving part.

p0011If the outer surface of the receiving part provided with transverse to bore tooth-like projections, this results in a barb-like clawing of the implant in the bone tissue, thereby reducing the likelihood of inadvertent Auslockerns the implant continues to decrease. Such projections may be formed for example as concentric rings or a thread.

p0012Groove-like projections which extend along the bore axis, which prevent unintentional rotation of the implant.

p0013The hammering of the nail can be facilitated by a steady decrease of the nail diameter towards the nail tip while reducing the risk of jamming. However, the decrease in diameter of the nail must be less than that of the bore of Aufdnahmeteiles.

p0014The bore of the receiving part does not necessarily enforce its entire length. This can be particularly advantageous with regard to the possible need for Wiederentfer opening of the implant. When fully bolt hole is formed after insertion of the implant at the distal end of the receiving part, a cavity - assuming the inserted beating in the receiving part includes nail distal not exactly with the receiving part from. In this cavity bone grows into and since the shape of the cavity is generally that of a truncated cone with decreasing diameter in the distal direction is the ingrown bone holds the implant in the explant. Distal closed receiving parts have material-related so far to be flexible enough that they deform when hitting the nail bulbous or spread apart by slits, which, however, again experiencing the problem of the cavity.

p0015If the implantation depth of the receiving part extending from the bone surface, the receiving part to further improve the proposed seat in the bone fragments with a radially outwardly projecting collar-like abutment or support flange may be provided.

p0016By a locking mechanism between the receiving part and the nail, again resulting in an improvement of the anchoring of the implant safety, since in this way a subsequent sliding back of the under intense pressure nail is prevented. For example, the nail having at its head end a concentrically arranged around the shaft groove, while the inner bore of the receiving part is provided at the end of its greatest diameter with a corresponding snap-ring groove. This limitation of the driving depth of the nail, there is also a well-defined spreading of the receiving part, so that conclusions about the effectiveness of the implant are possible.

p0017One particularly advantageous development of the invention, there is the entire implant of resorbable material, preferably made of polylactide. This eliminates the problem of the removal of the implant, thus also no limit on the barb-like clawing more is necessary. In this embodiment, the advantages of the invention are fully usable.

p0018Advantageous developments of the invention are characterized in the dependent claims and described in more detail below together with the description of the preferred embodiments of the invention with reference to FIGS. Show it:<ul><li>Figure 1 is an embodiment of an inventive implant in longitudinal section,</li><li>Figure 2 shows an embodiment of a receiving part in cross-section as viewed in the direction of implantation and</li><li>Figure 3 is an illustration of a use case in section.</li></ul>

p0019The inventive implant is shown in FIG 1 from a receiving part 1 and a nail 2. The receiving part 1 is provided with a tapered bore 3 formed as a cylindrical hollow body itself. The smallest diameter of the bore 3 of largest diam ser of the bore 3 is larger and smaller than the diameter of the nail shaft 4 over the entire length of the shaft 4. Also the nail stem 4 tapers from the head 5 of the nail 2. The diameter of the bore 3 but takes over equal distances from much stronger than that of the nail shank 4. the length of the bore 3 is approximately equal to that of the nail shaft 4. the outer circumferential surface 6 of the receiving part 1 is provided with sawtooth-like projections 7th The flanks of the teeth are arranged barb similar to the implantation direction.

p0020To facilitate the implantation and explantation of a possible, the receiving part 1 is provided with a flange 8 for resting on the bone. After insertion of the receiving part 1 in a corresponding hole, the 9 and 10 passes through the to be combined bone fragments, the nail 2 is driven into the tapered bore of the receiving part 3. 1 In this case, the distal end 11 of the receiving part 1 spreads on, whereby a barb-like clawing the sawtooth projections 7 with the surrounding bone of the fracture piece 10 is caused. In order to guarantee a permanent connection between the nail 2 and the receiving part 1 in a defined relative position of the nail shank 4 is provided with an annular recess 12 which is engageable within the bore 3 of the female part 1 in a corresponding annular groove. 13

p00212 shows another possible embodiment of the shell surface 6. Here, longitudinal grooves 14 which star jagged protruding in the cross-section corresponding to the view of the outer surface. 6 A longitudinal slot 15 at the distal end 11 of the receiving part 1 facilitates the spreading during insertion of the nail. 2

p0022The implant used for the union of two bone fragments 10 and 11 is shown in FIG. 3 The arrow directions indicate the force effects during insertion of the nail 2. It is seen that the fracture piece 9 is pressed onto the bone fragment 10, wherein there is a simultaneous spreading of the distal end 11 of the receiving part first Thus, the projections 7 of the lateral surface 6 of the receiving part 1 to dig barb with the bone fragment 10. The implant is preferably made of absorbable material, such as polylactic acid, so that the need for removal of the implant after healing of the breach deleted. Consequently, the advantages of the inventive implant, in particular the auslockerungsherabsetzende effect can be fully exploited by the spreading of the receiving part. 1

p0023The invention is not limited in its embodiment to the above-described preferred embodiment. Rather, a number of variants are conceivable, which make use of the described solution even for basically different configurations.