Rotary-rigid orthopaedic rod

Abstract

Apparatus and method for repairing a fractured bone. The apparatus and methods may involve an intramedullary rod. The rod may include a first elongated member and a second elongated member. Each of the first and second elongated members may be configured to bend in a first direction and to resist bending in a second direction. The first and second elongated members may be arranged such that; (1) the rod is bendable when the first direction of the first elongated member is aligned with the first direction of the second elongated member; and (2) the rod is rigid when the first direction of the first elongated member is aligned with the second direction of the second elongated member. Some embodiments may include rods that have sections that may be configured to be curved and rigid.

1 . An intramedullary rod defining a longitudinal axis and comprising:
 a first elongated member disposed within a second elongated member, the first elongated member having inner stress relief features and an inner longitudinal member and the second elongated member having outer stress relief features and an outer longitudinal member; and   an expandable bone support extending from an end of one of the first and second elongated members; wherein the elongated members are arranged so that:
 the rod is bendable when the second elongated member is circumferentially rotated about the longitudinal axis to align the inner stress relief features with the outer stress relief features; and 
 the rod is rigid when the second elongated member is circumferentially rotated about the longitudinal axis to align the inner longitudinal member with the outer stress relief features. 
   
     
     
         2 . The intramedullary rod of  claim 1  wherein:
 the expandable bone support is a first expandable bone support; 
 the end is a first end; and 
 a second expandable bone support extends from a second end of one of the first and second elongated members. 
 
     
     
         3 . The intramedullary rod of  claim 1  wherein the expandable bone support extends from a proximal end of the first member and a proximal end of the second member. 
     
     
         4 . The intramedullary rod of  claim 1  wherein the expandable bone support extends from a distal end of the first member and a distal end of the second member. 
     
     
         5 . The intramedullary rod of  claim 1  wherein:
 the outer stress relief features correspond to a first arrangement of slots that are longitudinally spaced from each other; and 
 the inner stress relief features correspond to a second arrangement of slots that are longitudinally spaced from each other. 
 
     
     
         6 . The intramedullary rod of  claim 5  wherein the slots are longitudinally separated by ribs. 
     
     
         7 . The intramedullary rod of  claim 5  wherein:
 the inner longitudinal member is a first inner longitudinal member; 
 the outer longitudinal member is a first outer longitudinal member; 
 the slots defined by the inner member are circumferentially separated by the first inner longitudinal member and a second inner longitudinal member; and 
 the slots defined by the outer member are circumferentially separated by the first outer longitudinal member and a second outer longitudinal member. 
 
     
     
         8 . The intramedullary rod of  claim 5  wherein the slots are configured to provide tension relief. 
     
     
         9 . The intramedullary rod of  claim 5  wherein the slots are configured to provide compression relief. 
     
     
         10 . The intramedullary rod of  claim 1  wherein:
 the outer stress relief features correspond to:
 a first arrangement of slots that are longitudinally spaced from each other for tension relief; and 
 a second arrangement of slots that are longitudinally spaced from each other to provide compression relief, wherein the first and second arrangements of slots are spaced circumferentially apart from each other; and 
 
 the inner stress relief features correspond to:
 a third arrangement of slots that are longitudinally spaced from each other for tension relief; and 
 a fourth arrangement of slots that are longitudinally spaced from each other to provide compression relief, wherein the third and fourth arrangements of slots are spaced circumferentially apparat from each other. 
 
 
     
     
         11 . The intramedullary rod of  claim 1  wherein both the inner stress relief features and the outer stress relief features include sinter. 
     
     
         12 . The intramedullary rod of  claim 1  wherein both the inner stress relief features and the outer stress relief features include kerfs. 
     
     
         13 . The intramedullary rod of  claim 1  wherein the first and second elongated members include, respectively, a first and second anchor receiving feature. 
     
     
         14 . The intramedullary rod of  claim 13  wherein the first and second elongated members are configured to be positioned relative to each other such that the first and second anchor receiving features are positioned to receive the same anchor. 
     
     
         15 . The intramedullary rod of  claim 14  wherein the first and second anchor receiving features are distal a first and a second arrangement of slots. 
     
     
         16 . The intramedullary rod of  claim 15  wherein the first and second elongated members include, respectively, a third and fourth anchor receiving feature. 
     
     
         17 . The intramedullary rod of  claim 16  wherein the third and fourth anchor receiving features are proximal the first and second arrangements of slots. 
     
     
         18  . The intramedullary rod of  claim 1  further comprising a locking mechanism that includes:
 a first adjustment flange attached to the first elongated member; 
 a second adjustment flange attached to the second elongated member; and 
 a setting element that is configured to prevent relative rotation about the longitudinal axis of the first elongated member with respect to the second elongated member. 
 
     
     
         19 . The intramedullary rod of  claim 18  wherein one of the first and second adjustment flanges is threaded. 
     
     
         20 . The intramedullary rod of  claim 1  wherein the first elongated member includes a first fixed curve and the second elongated member includes a second fixed curve. 
     
     
         21 . The intramedullary rod of  claim 1  wherein, when the rod is rigid, the rod includes one or more straight sections. 
     
     
         22 . The intramedullary rod of  claim 1  wherein, when the rod is rigid, the rod includes one or more curved sections. 
     
     
         23 . The intramedullary rod of  claim 1  wherein, when the rod is rigid, the rod includes one or more straight sections and one or more curved sections. 
     
     
         24 . The intramedullary rod of  claim 1  wherein the expandable bone support is configured to support one or more bone fragments. 
     
     
         25 . The intramedullary rod of  claim 1  wherein the inner member can rotate freely within the outer member. 
     
     
         26 . The intramedullary rod of  claim 1  wherein:
 the inner member has a first length; 
 the outer member has a second length; and 
 the first length is shorter than the second length. 
 
     
     
         27 . The intramedullary rod of  claim 1  wherein:
 the inner member has a first length; 
 the outer member has a second length; and 
 the first length is longer than the second length. 
 
     
     
         28 . The intramedullary rod of  claim 1  wherein:
 the inner member has a first length; 
 the outer member has a second length; and 
 the first length is substantially the same as the second length. 
 
     
     
         29 . The intramedullary rod of  claim 1  wherein the inner member is essentially solid. 
     
     
         30 . The intramedullary rod of  claim 1  wherein the inner member defines a central longitudinal void. 
     
     
         31 . The intramedullary rod of  claim 1  wherein the inner member is 
       porous. 
     
     
         32 . The intramedullary rod of  claim 1  wherein the inner member includes one or more elastic sections. 
     
     
         33 . The intramedullary rod of  claim 1  wherein the outer member includes one or more elastic sections. 
     
     
         34 . The intramedullary rod of  claim 1  wherein the inner member is disposed coaxially within the outer member. 
     
     
         35 . The intramedullary rod of  claim 1  wherein the inner member is disposed within the outer member such that the inner member is substantially flush with the outer member. 
     
     
         36 . The intramedullary rod of  claim 1  wherein the thickness of the inner member varies along a longitudinal axis defined by the inner member. 
     
     
         37 . The intramedullary rod of  claim 1  wherein the thickness of the outer member varies along a longitudinal axis defined by the outer member. 
     
     
         38 - 71 . (canceled)