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EP-4228535-B1 - PROSTHESES WITH FLEXIBLE SURFACE LAMELLAS

EP4228535B1EP 4228535 B1EP4228535 B1EP 4228535B1EP-4228535-B1

Inventors

  • LINK, HELMUT, D.
  • BAUER, ECKHARD

Dates

Publication Date
20260506
Application Date
20211013

Claims (12)

  1. A prosthesis or implant device for use in joint or bone repair comprising a stem (5) having a proximal end (6), a distal end (7), and an external surface (8), in which a portion of the stem (5) comprises two or more non-overlapping lamellas (13) around part or all of the circumference of the stem (5); wherein: each lamella (13) comprises an outer surface (18), an inner surface (19), and a thickness therebetween, wherein the inner surface of the lamella (13) faces the external surface of the stem (5), wherein each of the lamellas (13) comprises a proximal edge (14), a distal edge (15), a left edge (16), and a right edge (17), the proximal edge (14) being nearest the proximal end (6), the distal edge (15) being nearest the distal end (7); each lamella (13) is connected to the external surface of the stem (5) via a bending joint (21); the bending joint (21) is located on the inner surface (19) of the lamella at one of the edges (14, 15, 16, 17) of the lamella (13) or adjacent thereto, wherein the rest of the inner surface (19) of the lamella (13) and the external surface (8) of the stem (5) is separated by a space (22); and the bending joint (21) permits the space (22) between the rest of the inner surface (19) of the lamella (13) and the external surface (8) of the stem (5) to decrease upon application of a force to the outer surface of the lamella (13); characterized in that the bending joint (21) is on the right edge (17) of the lamella (13) or adjacent thereto, or on the left edge (16) of the lamella (13) or adjacent thereto.
  2. The prosthesis or implant device of claim 1, wherein the stem (5) comprises substantially a shape of a cylinder, preferably a circular cylinder or an elliptical cylinder.
  3. The prosthesis or implant device of claim 1, wherein the stem (5) comprises a taper between the proximal end (6) and the distal end (7).
  4. The prosthesis or implant device of claim 3, wherein the stem (5) comprises substantially a shape of a rounded cone or portion thereof, wherein the rounded cone is preferably a rounded circular cone or a rounded elliptical cone.
  5. The prosthesis or implant device of any one of claims 1 to 4, wherein the lamellas (13) are arranged in two or more columns of lamellas (13) in a direction of the proximal end (6) to the distal end (7) of the stem (5), and two or more rows of lamellas (13) around a circumference of the stem (5).
  6. The prosthesis or implant device of any one of claims 1 to 5, wherein the number of lamellas (13) in each column and each row is the same.
  7. The prosthesis or implant device of any one of claim 1 to 5, wherein the number of lamellas (13) in each column and each row is not the same.
  8. The prosthesis or implant device of any one of claims 1 to 7, wherein each of the lamellas (13) comprises substantially a shape of a quadrilateral, trapezoid or parallelogram.
  9. The prosthesis or implant device of any one of claims 1-8, wherein the bending joint (21) provides on the edge of the lamella (13), or adjacent thereto, a single continuous connection point (23) between the inner surface (19) of the lamella (13) and the external surface (8) of the stem (5).
  10. The prosthesis or implant device of any one of claims 1-8, wherein the bending joint (21) provides on the edge of the lamella (13), or adjacent thereto, two or more connection points (23) between the inner surface (19) of the lamella (13) and the external surface (8) of the stem (5).
  11. The prosthesis or implant device of any one of claims 1-10, wherein one or more of the lamellas (13) comprise a porous coating on the outer surface (18) of the lamellas (13) or a portion thereof.
  12. The implant of any one of claims 1-11, wherein the prothesis or implant device is one of the following: a prosthesis, a dental implant, or an intramedullary nail.

Description

FIELD OF INVENTION The invention is associated with the field of orthopedic implants, in particular prostheses and implants for joint replacement, bone repair, and restoration of function. BACKGROUND OF THE INVENTION Prostheses are a common tool for repairing joints that have lost full or partial function due to damage, disease, or injury. Surgical implantation of a prosthetic device often involves insertion of a portion of the device, such as a stem, into bone. For instance, in total hip arthroplasty the femoral component comprises a stem that is inserted into the femur, and in knee replacement surgery the tibial component has a stem that extends into the tibia. One of the main purposes of the stem is to provide stability of the prosthesis within the bone. Consequently, it is critical that the stem can be securely fitted. However, current stem designs are often inflexible and upon insertion can cause damage to the surrounding bone. For instance, stems known in the art are typically made of metal such as cobalt chrome alloy and, as demonstrated in Figures 1A-1C, the surface of these stems 1 may be smooth 2, textured 3, or have features such as ridges 4 made of same material as the rest of the stem. As a result, these stems are incompressible, and insertion of these stems into bone can damage the surrounding bone tissue. Such damage may impede osseointegration of the tissue with the stem and ultimately lead to an unstable implant. Prior art document FR2549717 discloses a femoral stem made of metal, a substance or material of suitable kind and having a permanent elastic deformability, which is provided, near one or several contact faces and over a suitable length, with at least one slit passing through the stem from one side to the other, so as to form one or more flexible tongues. When the stem is engaged in the femur, the tongues provide large contact surfaces and bend to prevent excessive pressure. FR2783702 discloses a self-locking prosthesis for a bone insert, which is provided with heat activated anchor wings formed of a shape memory material mounted on a central core. After insertion into the medullary canal of a bone, the wings expand due to the heat of the body and become locked. US2016317198 discloses a bone intramedullary fixation device comprising a body that is operable to change shape to expand and shorten the body, wherein (i) the body comprises an elastic material; (ii) the body has a plurality of prongs on each of a first end and a second end; (iii) the body has a shortening section between the prongs on the first end and the second end; and (iv) the shortening section is operable to shorten the body by moving from an elongated position to a shortened position. DE19705571 discloses an expanding dental implant with a hollow shaft which has an expanding section. An expanding section of the shaft near a first end of the implant provided with connectors for attachment to a tooth prosthesis. The shaft may have slits along it and an expanding body can be inserted into it, which expands the slits as well as the periphery of the shaft. When enlarged, the expanding section of the shaft has a greater circumference than that of the opposite end. US2017/0258557 discloses a dental implant system for supporting a cosmetic tooth prosthesis, which includes an elongated body adapted to be disposed in a jaw bone of a patient. The elongated body has a tapered outer surface that tapers along a longitudinal axis distally from a proximal end of the elongated body. The outer surface of the tapered elongated body includes a plurality of barbs for securing the elongated body in the jaw bone of the patient. FR2681239A1 discloses a femoral stem for a total hip prosthesis with primary fixation, having a tapered longitudinal profile from the head to the tip, a generally trapezoidal cross-section, and an ovalized cross-section of the stem. The anterior curvature of the stem, seen in a longitudinal plane, coincides with the curvature of the obturator arch of the femur in relation to the acetabulum. The proximal trochanter-diaphyseal portion of the stem is flared in the anteroposterior plane and has longitudinal grooves on its two main lateral faces. The trochanter-diaphyseal portion has two parallel and symmetrical longitudinal slots, open from the anterior-posterior face to the anterior face, said slots being of constant and identical cross-section. A similar femoral stem is disclosed in FR2634643. Thus, there remains a need in the art for a prosthesis with a stem component that can be inserted into bone without causing damage to the surrounding tissue. SUMMARY OF INVENTION According to the invention, there is provided a prothesis or implant device as claimed in claim 1. In one aspect, the present invention relates to a prosthesis for use in joint or bone repair, the prosthesis comprising a stem. In another aspect, the present invention relates to a dental implant for use in dental repair or restoration of function, the d