Systems and methods for using polyaxial plates
Certain embodiments of the invention provide plates for treating periarticular fractures or other non-full body weight bearing applications that combine polyaxial fixation with a low profile and enhanced contouring that more closely conforms to bone. Such plates can be designed to achieve buttressing effect and/or to be used in a reinforcement mode. Other features can be combined with these. Such plates can be created for use on bone sites such as on a tibia, fibula, metatarsal, calcaneous, other foot bone, humerus, radius, ulna, spinal, maxillofacial, as well as sites on other bones.
1. An implant comprising:
a first surface;
a second surface;
an aperture extending from the first surface to the second surface, the aperture including an inner surface and a central axis; and
a plurality of inwardly protruding fins defining a non-threaded opening for cooperating with a head portion of a bone fastener, each of the plurality of fins extending from the inner surface of the aperture towards the central axis of the aperture to a terminal end portion of the fin;
wherein each of the plurality of fins includes a first side surface and a second side surface, the first and second side surfaces having an inwardly tapered surface so that a distance between the first and second side surfaces adjacent to the inner surface is greater than a distance between the first and second side surfaces at the terminal end portion.
2. The implant of claim 1 , wherein each of the plurality of fins has an equal length as measured from the inner surface of the aperture to the terminal end portion of the fin.
3. The implant of claim 1 , wherein the terminal end portion of each of the plurality of fins resides an equal distance from the central axis of the aperture.
4. The implant of claim 1 , wherein the plurality of fins are each integrally connected to, and protruding from, the inner surface of the aperture.
5. The implant of claim 1 , wherein the plurality of fins are provided as a series of concavely indented, inwardly protruding fins.
6. The implant of claim 1 , wherein the plurality of fins are deflectable relative to a head portion of a fastener so that when the fastener is inserted into the aperture, the fastener is retained at any one of a plurality of angles relative to the aperture.
7. The implant of claim 6 , wherein the plurality of fins are deflectable so that the fins are interposed between threads formed on the head portion of the fastener.
8. The implant of claim 1 , wherein the plurality of fins are adapted and configured to deform in order to retain the head portion of the fastener.