Compliant anti-resorption implant

Abstract

Systems, devices, and methods for providing orthopedic implants that reduce the negative effects of stress shielding on surrounding bone structure. The orthopedic implants include two portions, a shell portion that forms an articulation interfaces and an intermediate portion that forms a bone interface. The shell portion is designed to reduce absorption of Carticulation forces and evenly distribute incident forces to the intermediate portion. The intermediate portion is designed to form a strong interface with native bone and transmit forces from the shell into the bone.

1 .- 18 . (canceled) 
     
     
         19 . A method of manufacturing an orthopedic implant, comprising:
 forming a shell region of the orthopedic implant; and   forming an intermediate region of the orthopedic implant, wherein the intermediate region has different mechanical properties than the shell region.   
     
     
         20 . The method of  claim 19 , wherein the shell region and intermediate region are formed by rapid manufacturing. 
     
     
         21 . The method of  claim 19 , wherein the shell region is formed using a different material than the intermediate region. 
     
     
         22 . The method of  claim 19 , wherein the intermediate region is formed by depositing material at a different density than the shell region. 
     
     
         23 . The method of  claim 19 , wherein the intermediate region is formed as a porous region, and the shell region is formed as a solid region. 
     
     
         24 . The method of  claim 19 , wherein forming the shell region comprises forming an outer articulation surface;
 wherein the shell region has a plurality of cross-sections; and   wherein each cross-section is taken perpendicular to the outer articulation surface.   
     
     
         25 . The method of  claim 24 , wherein each cross-section comprises a cross-sectional profile and a cross-sectional area; and
 wherein the method further comprises varying the cross-sectional profiles among the plurality of cross-sections while maintaining uniformity among the cross-sectional areas.   
     
     
         26 . The method of  claim 24 , further comprising:
 selecting a cross-sectional area; and   selecting a plurality of cross-sectional profiles, wherein each cross-sectional profile has the selected cross-sectional area, and wherein the plurality of cross-sectional profiles have different shapes; and   wherein forming the shell region comprises forming each of the cross-sections with a corresponding and respective cross-sectional profile and the selected cross-sectional area.   
     
     
         27 . The method of  claim 24 , wherein the plurality of cross-sections comprises a first cross-section and a second cross-section;
 wherein the first cross-section comprises a first cross-sectional profile and a first cross-sectional area;   wherein the second cross-section comprises a second cross-sectional profile and a second cross-sectional area;   wherein the first cross-sectional profile is different from the second cross-sectional profile; and   wherein the first cross-sectional area is equal to the second cross-sectional area.   
     
     
         28 . The method of  claim 27 , wherein the first cross-sectional profile has a first thickness dimension and a first width dimension;
 wherein the second cross-sectional profile has a second thickness dimension and a second width dimension;   wherein the first thickness dimension is greater than the second thickness dimension; and   wherein the first width dimension is less than the second width dimension.   
     
     
         29 . The method of  claim 24 , wherein the plurality of cross-sections comprises:
 a first cross-section of an anterior portion of the shell region, the first cross-section having a first cross-sectional area;   a second cross-section of a medial condyle portion of the shell region, the second cross-section having a second cross-sectional area; and   a third cross-section of a lateral condyle portion of the shell region, the third cross-section having a third cross-sectional area; and   wherein the first cross-sectional area is equal to the sum of the second cross-sectional area and the third cross-sectional area.   
     
     
         30 . A method of manufacturing an orthopedic implant, comprising:
 selecting a uniform cross-sectional area for a shell region of the implant;   selecting a plurality of different cross-sectional profiles for the shell region, wherein each of the cross-sectional profiles has the selected uniform cross-sectional area; and   forming the shell region, wherein the shell region includes an outer articulation surface and a plurality of cross-sections taken perpendicular to the outer articulation surface, and wherein each of the cross-sections has the uniform cross-sectional area and a corresponding and respective one of the plurality of different cross-sectional profiles.   
     
     
         31 . The method of  claim 30 , further comprising forming an intermediate region of the orthopedic implant, the intermediate region comprising a shell interface and a bone interface opposite the shell interface. 
     
     
         32 . The method of  claim 31 , wherein forming the shell region and forming the intermediate region comprise forming the intermediate region with different mechanical properties than the shell region. 
     
     
         33 . The method of  claim 30 , wherein a first of the cross-sections extends through an anterior portion of the shell such that the first of the cross-sections is contiguous, and wherein a second of the cross-sections extends through a lateral condyle of the shell and a medial condyle of the shell such that the second of the cross-sections is non-contiguous. 
     
     
         34 . The method of  claim 30 , wherein selecting the plurality of different cross-sectional profiles comprises:
 selecting a first cross-sectional profile of the plurality of different cross-sectional profiles with a first width dimension and a first thickness dimension; and   selecting a second cross-sectional profile of the plurality of different cross-sectional profiles with a second width dimension and a second thickness dimension; and   wherein the first width dimension is greater than the second width dimension; and wherein the first thickness dimension is less than the second thickness dimension.   
     
     
         35 . A method of manufacturing an orthopedic implant, comprising:
 forming a shell region comprising an outer articulation surface, a first condylar region, a second condylar region, and a junction of the first condylar region and the second condylar region; and   forming an intermediate region having a bone interface;   wherein forming the shell region comprises forming a strengthening rib; and   wherein forming the strengthening rib comprises:
 forming a first portion of the strengthening rib such that the first portion extends in a medial-lateral direction at the junction of the first condylar region and the second condylar region; and 
 forming a second portion of the strengthening rib such that the second portion extends in an inferior-superior direction at the first condylar region. 
   
     
     
         36 . The method of  claim 35 , wherein forming the strengthening rib further comprises forming a connecting portion connecting the first portion and the second portion. 
     
     
         37 . The method of  claim 36 , wherein the connecting portion is curved. 
     
     
         38 . The method of  claim 35  further comprising forming at least one additional strengthening rib, and wherein the at least one additional strengthening rib comprises at least one of a medial-lateral strengthening rib and an inferior-superior strengthening rib.