Fixation of orthopaedic devices

Abstract

The present invention provides an orthopaedic implant including a base device having a device surface and a fixation material attached to at least one portion of the device surface. The fixation material is configured to provide a minimally sufficient adhesive force to resist natural pull out caused by forces acting on the base device after implantation and bone growth. Also provided is a method of manufacturing an orthopaedic implant. A base device with a device surface is provided and a minimally sufficient adhesive force, that can resist natural pull out caused by forces acting on the base device after implantation and bone growth, is determined. A proper amount of fixation material sufficient to provide an adhesive force equal to the minimally sufficient adhesive force is determined and fixation material is applied to the device. When the proper amount of fixation material is applied to the device surface, application is stopped.

What is claimed is: 
     
         1 . An orthopaedic implant, comprising:
 a base device having a device surface; and   a fixation material attached to at least one portion of said device surface configured to provide a minimally sufficient adhesive force to resist natural pull out caused by forces acting on said base device after implantation and bone ingrowth.   
     
     
         2 . The orthopaedic implant of  claim 1 , wherein said base device is one of a bone screw, a bone pin and a bone plate. 
     
     
         3 . The orthopaedic implant of  claim 2 , wherein said fixation material is a porous material having a plurality of pores and a roughened outer surface. 
     
     
         4 . The orthopaedic implant of  claim 3 , wherein said fixation material is at least one of a metal and a polymer. 
     
     
         5 . The orthopaedic implant of  claim 4 , wherein said fixation material is at least one of titanium, cobalt-chrome and polyether ether ketone (PEEK). 
     
     
         6 . The orthopaedic implant of  claim 5 , wherein said base device comprises at least one of a metal and a polymer. 
     
     
         7 . The orthopaedic implant of  claim 6 , wherein said fixation material has a biologically active substance provided within said plurality of pores. 
     
     
         8 . The orthopaedic implant of  claim 7 , wherein said biologically active substance is at least one of a growth factor, an antibacterial agent, an anti-inflammatory, a bone growth promoter and a bone growth inhibitor. 
     
     
         9 . The orthopaedic implant of  claim 6 , wherein said base device has a plurality of openings formed on said device surface. 
     
     
         10 . The orthopaedic implant of  claim 9 , wherein said base device includes a reservoir in fluid communication with at least one of said plurality of openings. 
     
     
         11 . The orthopaedic implant of  claim 10 , wherein said reservoir is at least partially filled with a treatment substance. 
     
     
         12 . The orthopaedic implant of  claim 11 , wherein said treatment substance is at least one of a growth factor, an antibacterial agent, an anti-inflammatory, a bone growth promoter and a bone growth inhibitor. 
     
     
         13 . The orthopaedic implant of  claim 6 , wherein said base device is composed of PEEK. 
     
     
         14 . A method of manufacturing an orthopaedic implant, comprising the steps of:
 providing a base device having a device surface;   determining a minimally sufficient adhesive force to resist natural pull out caused by forces acting on said base device after implantation and bone ingrowth;   determining a proper amount of a fixation material sufficient to provide an adhesive force equal to said minimally sufficient adhesive force;   applying said fixation material to said device surface; and   stopping application of said fixation material to said device surface when said proper amount of said fixation material is applied.   
     
     
         15 . The method according to  claim 14 , further comprising the steps of:
 determining a proper placement of said proper amount of said fixation material to provide said adhesive force equal to said minimally sufficient adhesive force; and   distributing said proper amount of said fixation material on said device surface in accordance with said proper placement.   
     
     
         16 . The method according to  claim 15 , wherein said base device and said fixation material are composed of at least one of titanium, cobalt-chromium, and polyether ether ketone (PEEK). 
     
     
         17 . The method according to  claim 16 , wherein said fixation material includes a roughened surface and a plurality of pores. 
     
     
         18 . The method according to  claim 15 , wherein said proper placement is affected by at least one of a size of said base device, said device surface area, an intended implantation site, a diameter of said base device, and how proud said fixation material will be relative to said device surface. 
     
     
         19 . A method of performing an orthopaedic surgery, comprising the steps of:
 providing an orthopaedic implant having a device surface and a fixation material attached to said device surface, said fixation material configured to provide a minimally sufficient adhesive force to resist natural pull out caused by forces acting on said base device after implantation and bone ingrowth;   implanting said orthopaedic implant at an implantation site within a patient; and   revising the implantation of said orthopaedic implant by applying a revisionary force to said orthopaedic implant that is slightly greater than said minimally sufficient adhesive force.   
     
     
         20 . The method according to  claim 19 , wherein said revising step creates minimal trauma to the implantation site and surrounding anatomy structures of the patient.