Implant and implant system

Abstract

An implant system for implantation at a joint, the implant system including an implant device, the implant device comprising a body portion having first and second ends, and a first elongate member, extending from the first or second end of the body portion, the implant system further comprising a corresponding fixation device for securing the first elongate member to a subject, the fixation device comprising at least one latching element, the first elongate member comprising at least one cooperating element, the at least one cooperating element being capable of cooperating with said at least one latching element of the fixation device in use.

1 . An implant system for implantation at a joint, the implant system including an implant device, the implant device comprising:
 a body portion having first and second ends, and   a first elongate member, extending from the first or second end of the body portion,   a second elongate member extending from the other of the first or second end of the body portion from which the first elongate member extends,   the implant system further comprising a corresponding fixation device for securing the first elongate member to a subject, the fixation device comprising at least one latching element,   the implant system further comprises a second corresponding fixation device for securing the second elongate member to the subject, said fixation device comprising at least one latching element,   wherein the first elongate member is securable to a subject's tibia at a first location and the second elongate member is securable to a second location on the subject's tibia,   the first and second fixation devices each comprising a mechanism to fix the corresponding elongate member to the corresponding location on the subject's tibia, wherein each fixation device comprises external threading forming a plurality of latching elements to interlock with the corresponding elongate member.   
     
     
         2 . An implant system according to  claim 1 , wherein the first and/or second elongate member terminates in a free end. 
     
     
         3 . An implant system according to  claim 1 , wherein at least a portion of the first and/or second elongate member is substantially crescent shaped in cross-section. 
     
     
         4 . An implant system according to  claim 1 , wherein each fixation device is a screw, the screw being externally helically threaded. 
     
     
         5 . An implant system according to  claim 1 , wherein the first and/or second elongate member is insertable in a tunnel in a subject's bone, the tunnel having first and second open ends, the corresponding fixation device being insertable in the second end of the tunnel, such that the at least one latching element of said fixation device engages with the at least one cooperating element on said elongate member, the corresponding fixation device being securable non-movably relative to the tunnel, preventing the elongate member from being withdrawn from the tunnel via the first open end. 
     
     
         6 . An implant system according to  claim 1 , wherein the implant device further comprises a reinforcing element, which extends through the first elongate member and through the body portion of the implant device. 
     
     
         7 . An implant system according to  claim 6 , wherein the reinforcing element extends through the first elongate member, through the body portion of the implant device, and through the second elongate member. 
     
     
         8 . An implant system according to  claim 6 , wherein the reinforcing element is strap shaped. 
     
     
         9 . An implant device according to  claim 6 , wherein the body portion is substantially crescent shaped, having an arcuate rim, reinforcing element extends along, or close to and substantially parallel with, the arcuate outer rim of the body portion of the device. 
     
     
         10 . An implant device according to  claim 8 , wherein the strap shaped reinforcing element has a planar face, the planar face being substantially perpendicular to the transverse plane of the body portion of the device in use. 
     
     
         11 . An implant device according  claim 1 , wherein the implant device further comprises a structural element comprising a plurality of fibres embedded within the body portion. 
     
     
         12 . An implant device according to  claim 11 , wherein at least a portion of each of the fibres extends through the body portion. 
     
     
         13 . An implant device according to  claim 12 , wherein each of the fibres extends through the first elongate member, through the body portion of the implant device, and through the second elongate member. 
     
     
         14 . An implant device according to  claim 11 , wherein each of the fibres is coupled to the reinforcing element at at least one point along the length of said fibre. 
     
     
         15 . An implant device according to  claim 11 , wherein the plurality of fibres are arranged such that each fibre crosses over at least one other fibre. 
     
     
         16 . An implant device according to  claim 11 , wherein when the implant device is not subjected to any external forces, the fibres are arranged substantially parallel with the arcuate outer rim of the body portion. 
     
     
         17 . An implant device according to  claim 11 , wherein when the implant device is not subjected to any external forces, at least a portion of each fibre is arranged in wave like formation. 
     
     
         18 . An implant device according to  claim 17 , wherein at least a portion of each fibre extends between the posterior and anterior ends of the body portion in a sinusoidal shaped formation. 
     
     
         19 . An implant device according to  claim 11 , wherein the plurality of fibres comprises at least one electrospun anisotropic polymer sheet. 
     
     
         20 . An implant device according to  claim 1 , wherein the body portion is made of or includes a functionally graded material. 
     
     
         21 . An implant device according to  claim 1 , wherein the body portion has an elastic modulus gradient, the elastic modulus varying spatially within the body portion. 
     
     
         22 . An implant device according to  claim 21 , wherein the elastic modulus increases in a radial direction, towards the arcuate outer rim of the body portion. 
     
     
         23 . An implant device according to  claim 21 , wherein the elastic modulus increases in a circumferential direction towards free ends of the first and second elongate members. 
     
     
         24 . An implant device according to  claim 21 , wherein the elastic modulus increases towards the outer surface of the body portion. 
     
     
         25 . An implant device according to  claim 1 , wherein the body portion has a high tensile stiffness along an axis substantially parallel with the outer rim of the body portion, preferably in the range 50 MPa to 2 GPa and low shear stiffness in a plane substantially transverse to the outer rim of the body portion, preferably in the range 2 to 50 MPa. 
     
     
         26 . An implant device according to  claim 1 , wherein the body portion has a higher tensile stiffness along an axis substantially parallel with the outer rim of the body portion than its shear stiffness in a plane substantially transverse to the outer rim of the body portion.