Antibiotic delivery system and method for treating an infected synovial joint during re-implantation of an orthopedic prosthesis

Abstract

An antibiotic delivery system including an intramedullary stem that is adapted to be removably mounted into a medullary canal of a bone. The stem includes a body having an inlet adapted to be in fluid communication with a source of liquid-borne antibiotic and a plurality of outlets disposed along the stem. A channel extends between the inlet and the plurality of outlets for delivering a fluid-borne antibiotic from the inlet to the plurality of outlets so as to distribute the antibiotic along the medullary canal in a controlled fashion. A method of treating an infected joint during a two-stage re-implantation of an orthopedic implant is also disclosed.

What is claimed is: 
     
       1. An antibiotic delivery system comprising:
 a femoral intramedullary stem adapted to be removably mounted into a medullary canal of a femur bone, said femoral intramedullary stem including a body having a proximate end and a distal end disposed remote from said proximate end, said body including a plurality of fins extending therealong and disposed in spaced angular relationship with respect to each other so as to define valleys that provide fluid flow spaces disposed between adjacent fins, said fins adapted to engage said medullary canal in a removably stable fashion, a femoral head and a neck extending from said proximal end of said body and between said body and said femoral head, said femoral intramedullary stem including at least one inlet, and a plurality of outlets disposed along said stem and between an outer surface of one of said plurality of adjacent fins in said valleys and in fluid communication with said fluid flow spaces and a channel extending between said inlet and said plurality of outlets, said femoral head having a plurality of outlets and a channel extending between said at least one inlet and said plurality of outlets for delivering fluid-borne antibiotics from said at least one inlet to said plurality of outlets so as to distribute said antibiotic along said intramedullary canal and the socket of a hip joint in a controlled fashion.   
     
     
       2. An antibiotic delivery system as set forth in  claim 1 , wherein said body includes an inlet and said femoral head includes an inlet, both inlets being in fluid communication with a source of fluid-borne antibiotic. 
     
     
       3. An antibiotic delivery system as set forth in  claim 1 , wherein said femoral head has a hemispherical shape so as to be complimentarily received in the socket of a hip joint. 
     
     
       4. A method of treating an infected joint during a two-stage re-implantation of an orthopedic implant, said method comprising the steps of: removing the infected implants mounted to the medullary canal of a bone; debriding the medullary canal; installing an intramedullary stem into the medullary canal where the stem includes an inlet, a plurality of outlets and a channel extending between the inlet and the plurality of outlets; said stem including a plurality of fins extending along a longitudinal axis of the stem and disposed in spaced angular relationship with respect to each other so as to define valleys that provide fluid flow spaces disposed between adjacent fins and a plurality of outlets disposed along said stem and between an outer surface of one of said plurality of adjacent fins in said valleys and in fluid communication with said fluid flow spaces providing a source of fluid-borne antibiotic to the inlet of the intramedullary stem so as to distribute the antibiotic into the medullary canal in a controlled fashion. 
     
     
       5. A method of treating an infected orthopedic implant as set forth in  claim 4 , wherein said step of installing an intramedullary stem includes installing a tibial intramedullary stem into the medullary canal of the tibia bone and installing a femoral intramedullary stem into the medullary canal of a femur bone. 
     
     
       6. A method of treating an infected orthopedic implant as set forth in  claim 5 , wherein the method further includes the step of positioning a coupler between the tibial intramedullary stem and the femoral intramedullary stem so as to provide axial stability between the tibial and femoral intramedullary stems. 
     
     
       7. A method of treating an infected orthopedic implant as set forth in  claim 6 , wherein the method further includes the step of establishing fluid communication between the coupler and the inlet of the tibial and femoral intramedullary stems and providing fluid communication between the coupler and a source of fluid-borne antibiotic so as to distribute the antibiotic through the tibial and femoral intramedullary stems and along the medullary canals in a controlled fashion. 
     
     
       8. A method of treating infected tissue in a patient, the method comprising:
 a) installing a first intramedullary stem into a first medullary canal of a first bone, said intramedullary stem comprising a longitudinal axis, wherein said installing comprises engaging an outer stem surface of the first intramedullary stem with said first medullary canal of the first bone, the outer stem surface comprising a plurality of fins extending along said first intramedullary stem, said plurality of fins disposed in spaced angular relationship so as to define a plurality of valleys, each of said plurality of valleys disposed between an adjacent pair of fins and providing a fluid-flow space between said adjacent pair of fins when said stem is installed in said first medullary canal,   wherein the first intramedullary stem comprises a first inlet, a first plurality of outlets and a first channel therein and in fluid communication with each of said first inlet, said first plurality of outlets and each of the fluid-flow spaces, and further wherein said first plurality of outlets is disposed along said stem in said plurality of valleys; and   b) infusing a first fluid through said first inlet, said first channel and said first plurality of outlets directly into said medullary canal in a controlled fashion to treat said infected tissue.   
     
     
       9. The method of  claim 8 , further comprising removing a second fluid from said first medullary canal. 
     
     
       10. The method of  claim 9 , wherein said first fluid comprises at least one of an antibiotic, an irrigating fluid, a debriding fluid, a cleansing fluid and a fluid-borne agent for treating infected tissue. 
     
     
       11. The method of  claim 9 , wherein said second fluid comprises excessive fluid. 
     
     
       12. The method of  claim 9 , further comprising introducing an additional dose of fresh fluid into said first medullary canal via said first inlet, said first channel and said first plurality of outlets after said removing said second fluid. 
     
     
       13. The method of  claim 12 , wherein said fresh fluid comprises fresh antibiotic. 
     
     
       14. The method of  claim 12 , further comprising performing said method over a period of approximately one week to treat said infected tissue. 
     
     
       15. The method of  claim 14 , further comprising, after said period of approximately one week, removing said first intramedullary stem from said first intramedullary canal. 
     
     
       16. The method of  claim 15 , further comprising implanting an implant into said first medullary canal after removing said first intramedullary stem. 
     
     
       17. The method of  claim 9 , wherein said infusing comprises a first pump in fluid communication with said first channel and a source of first fluid, said first pump pumping the first fluid into said first medullary canal through said first channel. 
     
     
       18. The method of  claim 17 , wherein said first fluid comprises fluid-borne antibiotic, and wherein said pumping comprises said first pump controlling infusion of said fluid-borne antibiotic from said source into said first medullary canal. 
     
     
       19. The method of  claim 17 , wherein said removing comprises using negative pressure to remove said second fluid from said first medullary canal. 
     
     
       20. The method of  claim 19 , wherein a second pump generates said negative pressure to remove said second fluid, and further wherein said first pump is different from said second pump. 
     
     
       21. The method of  claim 9 , wherein said second fluid comprises a portion of said first fluid. 
     
     
       22. The method of  claim 9 , wherein said removing comprises using negative pressure to remove said second fluid from said first medullary canal. 
     
     
       23. The method of  claim 22 , where a pump generates said negative pressure to remove said second fluid. 
     
     
       24. The method of  claim 23 , where said pump for generating said negative pressure also serves to infuse said first fluid from a first fluid source into said first medullary canal. 
     
     
       25. The method of  claim 22 , further comprising applying a porous material to a wound of said patient, said wound providing access to said first medullary canal, and removing said second fluid via said negative pressure through said porous material. 
     
     
       26. The method of  claim 25 , wherein said porous material comprises a sponge. 
     
     
       27. The method of  claim 8 , further comprising, with said first medullary canal comprising said infected tissue, removing at least one implant from the first medullary canal before installing said first intramedullary stem. 
     
     
       28. The method of  claim 27 , further comprising debriding the first medullary canal before installing said first intramedullary stem. 
     
     
       29. The method of  claim 8 , wherein each of said plurality of fins has an outermost surface for engaging said first medullary canal. 
     
     
       30. The method of  claim 29 , wherein each of said outermost surfaces of said plurality of fins is generally planar or smooth. 
     
     
       31. The method of  claim 29 , wherein each of said outermost surfaces of said plurality of fins comprises a plurality of peaks, wherein said plurality of peaks are adapted to contact said first medullary canal. 
     
     
       32. The method of  claim 8 , wherein a first cross-section of a proximal portion of said stem has a larger area than a second cross-section of a distal portion of said stem, such that said stem has a tapered shape. 
     
     
       33. The method of  claim 8 , wherein at least one outlet of said first plurality of outlets comprises a larger outlet size than a second outlet. 
     
     
       34. The method of  claim 33 , wherein said at least one outlet is closer to a distal tip of said stem than said second outlet. 
     
     
       35. The method of  claim 8 , wherein said first bone is one of a femur and a tibia. 
     
     
       36. The method of  claim 8 , further comprising installing a second intramedullary stem into a second medullary canal of a second bone, the second intramedullary stem comprising a second inlet, a second channel therein and in fluid communication with said second inlet and a second plurality of outlets disposed along said second intramedullary stem. 
     
     
       37. The method of  claim 36 , wherein said first bone is a femur and said second bone is a tibia. 
     
     
       38. The method of  claim 36 , further comprising coupling a coupler to a first proximal portion of said first intramedullary stem and a second proximal portion of said second intramedullary stem. 
     
     
       39. The method of  claim 38 , wherein said coupler, when coupled to said first and second intramedullary stems, provides structural rigidity to a joint of said patient. 
     
     
       40. The method of  claim 39 , further comprising selecting said coupler from a plurality of couplers of different sizes in order to achieve a desired distraction of said joint. 
     
     
       41. The method of  claim 38 , wherein said coupler comprises a coupler inlet, and further wherein, when said coupler is coupled to said first and second intramedullary stems, said coupler inlet is in fluid communication with said first and second inlets. 
     
     
       42. The method of  claim 41 , further comprising placing the coupler inlet in fluid communication with a source of first fluid, and infusing said first fluid via said coupler inlet and first plurality of outlets into said first medullary canal and via said coupler inlet and second plurality of outlets into said second medullary canal. 
     
     
       43. The method of  claim 42 , further comprising removing said second fluid from said first medullary canal and said second medullary canal. 
     
     
       44. The method of  claim 43 , wherein said removing said second fluid from said first and second medullary canals comprises using negative pressure. 
     
     
       45. The method of  claim 42 , wherein said first fluid comprises at least one of an antibiotic, an irrigating fluid, a debriding fluid, a cleansing fluid, and a fluid-borne agent for treating infected tissue. 
     
     
       46. The method of  claim 8 , wherein a proximal portion of said first intramedullary stem is coupled to a head, said head comprising a head outer surface adapted to engage a socket of a second bone, said head outer surface comprising a second plurality of outlets in fluid communication with a second channel within said head. 
     
     
       47. The implant of  claim 46 , wherein the head is releasably coupled to the first intramedullary stem. 
     
     
       48. The method of  claim 46 , further comprising engaging said head with said socket and infusing said first fluid via said first plurality of outlets into said first medullary canal and via said second plurality of outlets into said socket. 
     
     
       49. The method of  claim 48 , further comprising removing said second fluid from said first medullary canal and said socket. 
     
     
       50. The method of  claim 49 , wherein said removing said second fluid from said first medullary canal and said socket comprises using negative pressure. 
     
     
       51. The method of  claim 48 , wherein said second channel is in fluid communication with said first inlet, and wherein said infusing said first fluid comprises infusing said first fluid via said first inlet and said first plurality of outlets into said first medullary canal and via said first inlet and said second plurality of outlets into said socket. 
     
     
       52. The method of  claim 48 , where said head further comprises a second inlet in fluid communication with said second channel, and wherein said infusing said first fluid comprises infusing said first fluid via said first inlet and said first plurality of outlets into said first medullary canal and via said second inlet and said second plurality of outlets into said socket. 
     
     
       53. The method of  claim 47 , wherein said head is hemispherically shaped. 
     
     
       54. The method of  claim 47 , wherein said first bone is a femur and said socket of said second bone is a hip socket. 
     
     
       55. The method of  claim 47 , wherein said head is coupled to said stem via a neck portion. 
     
     
       56. The method of  claim 8 , wherein said first intramedullary stem comprises a material to reduce bacterial contamination. 
     
     
       57. The method of  claim 56 , wherein said material comprises a copper alloy. 
     
     
       58. The method of  claim 8 , wherein a proximal portion of said first intramedullary stem comprises said first inlet. 
     
     
       59. The method of  claim 58 , wherein said proximal portion of said first intramedullary stem further comprises a base plate. 
     
     
       60. The method of  claim 59 , wherein said base plate comprises said first inlet.