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 comprising:
 a first elongated member and a second elongated member, each of the first and second elongated members having a first direction and a second direction and being configured to bend in the first direction and to resist bending in the second direction;   
       wherein the elongated members are arranged such that:
 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 
 the rod is rigid when the first direction of the first elongated member is aligned with the second direction of the second elongated member. 
 
     
     
         2 . The intramedullary rod of  claim 1  wherein the first elongated member is disposed coaxially within the second elongated member. 
     
     
         3 . The intramedullary rod of  claim 1  wherein each of the first directions corresponds to an arrangement of slots that are longitudinally spaced from each other. 
     
     
         4 . The intramedullary rod of  claim 3  wherein the slots are configured to provide tension relief. 
     
     
         5 . The intramedullary rod of  claim 3  wherein the slots are configured to provide compression relief. 
     
     
         6 . The intramedullary rod of  claim 2  wherein:
 the first directions 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; and 
 
 the first and second arrangements of slots are spaced circumferentially apart from each other on one of the elongated members. 
 
     
     
         7 . The intramedullary rod of  claim 1  wherein the first and second elongated members include, respectively, a first and second anchor receiving feature. 
     
     
         8 . The intramedullary rod of  claim 7  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. 
     
     
         9 . The intramedullary rod of  claim 8  wherein the first and second anchor receiving features are distal a first and a second arrangement of slots. 
     
     
         10 . The intramedullary rod of  claim 9  wherein the first and second elongated members include, respectively, a third and fourth anchor receiving feature. 
     
     
         11 . The intramedullary rod of  claim 10  wherein the third and fourth anchor receiving features are proximal the first and second arrangements of slots. 
     
     
         12 . The intramedullary rod of  claim 1  further comprising, when the rod includes a longitudinal axis, a locking mechanism that includes:
 a first attachment to the first elongated member; 
 a second attachment to the second elongated member; and 
 a bridging member that is configured to prevent relative rotation about the longitudinal axis of the first elongated member with respect to the second elongated member. 
 
     
     
         13 . The intramedullary rod of  claim 12  wherein one of the first and second attachments is threaded. 
     
     
         14 . The intramedullary rod of  claim 1  wherein the first elongated member comprises a fixed-curve portion that includes a fixed curve, the fixed curve defining a fixed-curve plane, the fixed-curve plane including the second direction of the first elongated member. 
     
     
         15 . The intramedullary rod of  claim 14  wherein, when the fixed-curve portion is a first fixed-curve portion, the second elongated member comprises a second fixed-curve portion that includes a second fixed curve, the second fixed curve defining a second fixed-curve plane, the second fixed curve plane including the second direction of the second elongated member. 
     
     
         16 . The intramedullary rod of  claim 14  wherein:
 the fixed-curve portion includes a first segment and a second segment, the second segment being attached to the first segment; 
 the first segment includes a first rigid bend; 
 the second segment includes a second rigid bend; and, 
 
       when the first and second bends lie in the fixed-curve plane, the fixed-curve portion is resistant to bending in the fixed-curve plane and the fixed curve portion is not resistant to bending in a plane that is different from the fixed-curve plane. 
     
     
         17 . The intramedullary rod of  claim 14  wherein the first segment is linked to the second segment by an articulating linkage. 
     
     
         18 . The intramedullary rod of  claim 14  wherein the first and second segments are formed from a unitary body. 
     
     
         19 . The intramedullary rod of  claim 18  wherein the unitary body is a tube. 
     
     
         20 . The intramedullary rod of  claim 1  wherein the first elongated member comprises a segment that includes:
 a first end that includes a first linkage that has a first pivot axis, the first linkage providing a connection to a first neighboring segment; and 
 a second end that is spaced a distance apart from the first end and includes a second linkage that has a second pivot axis, the second linkage providing a connection to a second neighboring segment; 
 
       wherein:
 the distance defines a longitudinal axis; and 
 the second pivot axis is angularly offset, about the longitudinal axis, from the first pivot axis. 
 
     
     
         21 . The intramedullary rod of  claim 20  wherein the second pivot axis defines the second direction of the first elongated member. 
     
     
         22 . The intramedullary rod of  claim 20  wherein the first pivot axis defines the first direction of the first elongated member. 
     
     
         23 . The intramedullary rod of  claim 1  wherein the first elongated member comprises a segment that includes:
 a first end that includes a first linkage that has a first pivot axis, the first linkage providing a connection to a first neighboring segment; and 
 a second end that is spaced a distance apart from the first end and includes a second linkage that has a second pivot axis, the second linkage providing a connection to a second neighboring segment; 
 
       wherein:
 the distance defines a longitudinal axis; and 
 the first and second pivot axes define intersecting lines when the segment is viewed along a direction that is substantially normal to the longitudinal axis. 
 
     
     
         24 . The intramedullary rod of  claim 23  wherein the second pivot axis defines the second direction of the first elongated member. 
     
     
         25 . The intramedullary rod of  claim 23  wherein the first pivot axis defines the first direction of the first elongated member. 
     
     
         26 . The intramedullary rod of  claim 23  wherein the second pivot axis is angularly offset, about the longitudinal axis, from the first pivot axis. 
     
     
         27 . The intramedullary rod of  claim 26  wherein the first and second elongated members include, respectively, a first and second anchor receiving feature. 
     
     
         28 . The intramedullary rod of  claim 27  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. 
     
     
         29 . The intramedullary rod of  claim 1  further comprising a bone support extending from an end of one of the first and second elongated members. 
     
     
         30 . The intramedullary rod of  claim 29  further comprising, when the bone support is a first bone support and the end is a first end, a second bone support extending from a second end of one of the first and second elongated members. 
     
     
         31 . An intramedullary rod comprising:
 an outer tubular member that is configured to bend about a first axis; and   an inner member disposed inside the outer tubular member, the inner member including a segment that is configured to move:
 relative to a first attached neighboring segment, about a second axis; and 
 relative to a second attached neighboring segment opposite the first attached neighboring segment, about a third axis; 
   
       wherein:
 the second axis is substantially parallel to the first axis; and 
 the third axis is substantially perpendicular to the first axis. 
 
     
     
         32 . The intramedullary rod of  claim 31  wherein the inner member is configured to rotate, relative to the outer tubular member, from a first position in which the second axis is parallel to the first axis, and the rod is bendable, to a second position in which the third axis is substantially perpendicular to the first axis, and the rod is resistant to bending. 
     
     
         33 . The intramedullary rod of  claim 31  wherein the segment is configured to move relative to the first and second neighboring segments by respective operation of first and second articulating linkages. 
     
     
         34 . The intramedullary rod of  claim 33  wherein the segment, the first neighboring segment and the second neighboring segment are formed from a unitary body. 
     
     
         35 . The intramedullary rod of  claim 34  wherein the unitary body is a tube. 
     
     
         36 . A method for delivering an intramedullary rod to a bone, the method comprising:
 inserting a flexible intramedullary rod through an angled access hole into an intramedullary channel; and   configuring the intramedullary rod in a rigid configuration by aligning a bending feature of a first sleeve with a non-bending feature of a second sleeve.   
     
     
         37 . The method of  claim 36  further comprising, when the bone has a longitudinal axis, drilling the angled access hole at angle to the bone axis. 
     
     
         38 . The method of  claim 36  further comprising, when the bone includes an intramedullary space, preparing the intramedullary space to receive the rod. 
     
     
         39 . The method of  claim 36  further comprising aligning the first and second sleeves. 
     
     
         40 . The method of  claim 36  further comprising inserting the rod into the intramedullary space. 
     
     
         41 . The method of  claim 36  further comprising rotating the first sleeve relative to the second sleeve. 
     
     
         42 . The method of  claim 36  further comprising fixing a rotational offset between the first sleeve and the second sleeve. 
     
     
         43 . The method of  claim 36  further comprising anchoring a distal end of the rod to the bone. 
     
     
         44 . The method of  claim 36  further comprising applying a tension to the rod. 
     
     
         45 . The method of  claim 36  further comprising anchoring a proximal end of the rod to the bone. 
     
     
         46 . The method of  claim 36  further comprising expanding a bone support at one end of the rod.