JP2016517783A - Implant for fracture stabilization outside the cortex - Google Patents

Abstract

The present invention relates to an implant for osteosynthesis (1), wherein the implant (1) is pressed against the bone by one or more fastening wires, cables or bands and the pressing is set by fastening under tension A contact area (11) that prevents relative movement of the implant (1) is included on the underside (10).

Description

  The present invention relates in particular to an implant for human osteosynthesis, the implant being pressed against the bone by a wire, cable or band, so that displacement of the bone relative to the implant is prevented due to the resulting contact force. It interacts with the bone surface in a specially formed contact area on the underside.

  Osteointegrated implants have been used in human and veterinary medicine for a considerable period of time in various configurations and fixation methods. A very commonly used design is a plate with holes that need to be screwed to the bone. For fractures in or near implants that are inserted into the intramedullary canal of long bones, such as for example joint prostheses, severe constraints can be imposed when screwing in close proximity to such implants. Osteoporosis and thin cortex combined with such implants in the intramedullary canal present the greatest challenge in fracture fixation around the joint prosthesis. Fixation using screws is almost impossible in the thin cortex near the implant placed in the intramedullary canal. This is especially true for implants that include set screw fixation, as commonly used and recommended in osteoporotic bone. This is because the screw arrangement specified by the locking function provides only a limited arrangement range. Thus, as known from various publications, screws that interfere with the implant in the intramedullary canal can cause premature damage to the osteosynthesis. In addition, the insertion of screws in close proximity to this contact surface can damage the implant / bone contact surface, and in the case of a joint prosthesis, the joint can be partially destroyed, leading to an early It is clear from other publications that it causes loosening.

EP 0 355 035 US Patent Application Publication No. 2010/0094294 International Publication No. 2006/039900

  All of these findings indicate that plate fixation is purely extracortical, especially with or without fractures in or around the implant placed in the intramedullary canal, with or without a bonded interface. Is desirable. A known solution for this is to use fasteners with wires, cables or bands to attach the plate to the bone instead of fixing the plate using screws. However, experience shows that such fixation using conventional plate systems lacks rotational stability and results in a high damage rate.

  In order to improve the stability of this type of fixation, different plate inserts have been developed for improved connection with wires. Nevertheless, such an insert that does not directly contact the bone will not improve rotational stability.

  An insert that requires fixation of a single cortical bone in a short hole improves rotational stability, but is at least partially affected by the aforementioned screw fixation disadvantages. With thinner skin layers, these single skin layer inserts cannot be placed deep enough in the bone, affecting the stability of these inserts.

  The present disclosure provides rotational and axially stable fixation using an extrascleral fastener with wires, cables or bands. The most important for rotation and stable axial fixation of the implant by the fastener is the implant / bone contact surface underneath the implant facing the bone, which contact surface is generated by the fastener This is caused by the contact force between the bone and the bone, in particular by the tension of the fastening part. It can be clearly estimated that this implant / bone interface should be as large as possible. However, various publications indicate that extensive implant / bone contact surfaces have drawbacks that can inhibit blood flow to the periosteum and underlying bone and thus cause bone necrosis. Known from things.

  From EP 0 355 035, the implant has a certain contact point between the implant and the bone, and provides the smallest possible contact area when the implant presses the bone by its fixation. It has been known. These defined contact points aim to keep the entire contact area of the implant to the bone as small as possible in order to allow blood flow in the periosteum and therefore not significantly disturbed in the bone. The disadvantage of this concept is that only a few of these contact points are actually in contact with the bone, these points do not have a surface defined to engage the bone surface, and the implant along the bone surface It can interfere with movement.

  The disclosed implants expand at individual contact areas to provide various contact teeth formed by special surfaces, whereby the individual contact areas apply a pressing force through the periosteum into the bone itself, In this way, the displacement of the implant along the bone surface in all directions can be prevented. From US 2010/0094294 and WO 2006/039900, an implant is known which has a spike in the contact area between the implant and the bone, this spike fastening itself. Fix to the inside of the bone under the tension of the part. Such spikes have the disadvantage of penetrating the periosteum and substantially damaging the bone, even though there is still little resistance to any movement along the bone surface. Especially in very thin bone walls, as is often seen in osteoporotic bones, such spikes can destroy the bone wall while retaining its retention force, thus greatly impairing stability.

  The disclosed implant solves this problem by providing at least one flat contact area with a special surface. This special surface interlocks the bone surface through the engagement of multiple spikes and / or teeth on the surface of this contact area in the periosteum and underlying bone, thereby providing the desired rotational and axial orientation. Provides a stable implant / bone contact surface.

FIG. 3 is a schematic view of an embodiment of the implant of the present invention in the form of a plate having a lower side that includes a special contact area that engages as a contact surface with bone. FIG. 6 is a lower view of such an implant of the present invention showing the groove structure on the surface of the contact area. FIG. 3 is a top view of such an implant of the present invention that can be connected to a plate by a cylindrical projection.

  The embodiment of the implant (1) shown in FIG. 1 is one of many possible variants. The implant (1) comprises a general means for fixing one or more bone screws (4) by receiving them in the through-hole (40) and a fastening part for holding the implant (1) and the bone (3) (2) Provide both fixing means. On the underside (10) of the illustrated implant (1), the contact area (11) is oriented in different directions, forming spikes and / or teeth (13) comprising aligned elongated sharp contact ends (131). A large number of grooves (12) are provided.

  The upper side (20) of the implant (1) is for a fastening part (2) that holds in a stable position relative to the implant when the fastening part (2) engages in one of these grooves (21). You may provide a groove part (21) as a connection means.

  The view of the contact area (11) on the lower side (10) of the implant (1) of the invention shown in FIG. 2 shows the shape (120) of the groove (12), the direction (121) of the groove (12) and the same direction ( 121a-n) illustrates the way in which the teeth (13) are formed by the distance (122a-n) between the grooves (12). Preferably, the tooth (13) in the contact area (11) does not have a sharp point, but has an elongated sharp end (131) facing in a different direction (131a-n), the elongated sharp end. The part (131) increases the contact area of the individual teeth and improves the rotation and axial stability of the implant / bone contact surface.

  The embodiment of the implant (1) shown in FIG. 3 additionally comprises a cylindrical projection (51) on the upper side (20) as a securing means (50), so that at least one implant according to the invention is commercially available. Secure to at least one hole in the osteosynthesis plate. The implant (1) of the present invention may comprise any shape securing means (50) for external or internal fixation of any other shape implant (5), but under the implant (1). The condition is that it does not interfere with the contact area (11) on the side (10) or otherwise damage the contact surface between the contact area (11) and the bone (3). Such a fixing means (50) is an internal protrusion specially provided on one or more side surfaces (30), either in one or more through holes (40), depending on the contour of the implant (1) itself. Or it may be provided by an external protrusion (51).

Claims (14)

a) a lower side (10) comprising one or more protruding contact areas (11);
b) the upper side (20);
c) an implant (1) for fixing to a bone (3) by pressing comprising one or more side surfaces (30),
d) The one or more contact areas (11) are provided with teeth (13) formed by a plurality of grooves (12) arranged in two or more different directions (121a-n). An implant.   Implant according to claim 1, characterized in that the tooth (13) has a sharp contact point or contact end (131) facing the bone (3).   Implant according to claim 2, characterized in that the contact ends (131) are arranged in two or more different directions (131a-n).   A groove (12) arranged in one or more directions (121a-m) is bent so that the obtained contact end (131) is bent in the same way, according to claim 2 or 3 The described implant.   Implant according to any one of the preceding claims, characterized in that the implant (1) can be pressed onto the bone (3) by means of one or more holding fasteners (2).   Implant according to any one of the preceding claims, characterized in that the upper side (20) comprises one or more grooves (21). Each of the one or more grooves (21)
a) accepting one fastening part (2), and
7. Implant according to claims 5 and 6, characterized in that it is arranged to fix b) the fastening part (2) against movement with respect to the implant (1) under tension.   Implant according to any one of the preceding claims, characterized in that the implant (1) comprises one or more through holes (40).   Implant according to claim 8, characterized in that at least one through-hole (40) is configured to receive a bone screw (2) and to fix the implant (1) to the bone (3).   Implant according to any one of the preceding claims, characterized in that the implant (1) comprises one or more fixing means (50). At least one securing means (50),
a) the implant (1) is receptive to the osteosynthesis plate (5), and
Implant according to claim 10, characterized in that it is configured such that b) the implant (1) can be fixed in the osteosynthesis plate (5) so as not to move relative to the osteosynthesis plate (5). At least one securing means (50),
a) receiving support means (5), and
Implant according to claim 10, characterized in that it is arranged to b) fix the support means (5) against movement with respect to the implant (1). Support means (5) according to claim 12,
a) connecting several implants (1) according to any one of claims 1 to 13 to each other; and
b) Support means (5), characterized in that they are arranged to fix these implants (1) against movement relative to each other.   14. Implant (1) can be formed at least on the lower side (10) by pressing the implant (1) so as to conform to the shape of the bone (3). The implant according to any one of the above.

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