Early Intervention Knee Implant Device and Methods

Abstract

A replacement knee implant has a femoral implant and a tibial implant, each of which are inset in a bone surface. The tibial implant is generally elongated with one end rounded and an opposite end conforming to the shape of the tibia, and is made of a metal alloy or a ceramic. The upper surface is dished while the lower surface is planar and can be parallel or sloped relative to the upper surface, and can have a keel for fixation. The femoral implant for implementation in a femoral condyle is rounded such that, when implemented, the femoral implant is flush at the anterior and posterior sides and protruding away from the femur between the anterior and posterior ends. The femoral implant can have an elongated keel for extending into the femur, and can be made from a highly cross-linked polyethylene.

What is claimed is: 
     
         1 . A tibial resurfacing implant, comprising:
 a tibial implant structure comprising:
 a surfacing portion with a tibia-facing surface and a femur-facing surface, wherein the surfacing portion is substantially planar; 
 a keel extending from the tibia-facing surface of the surfacing portion in a direction substantially perpendicular to the surfacing portion, wherein the keel comprises a substantially planar element; and 
 a cylindrical element extending from an anterior end of the keel to a posterior end of the keel. 
   
     
     
         2 . The tibial resurfacing implant of  claim 1 , wherein the surfacing portion is configured to be implanted along a surface of a resected condyle of a tibia, the surfacing portion having a lateral end that is configured to be positioned along a lateral portion of the tibia and a medial end that is configured to be positioned along a medial portion of the tibia, and wherein the keel extends from the tibia-facing surface along a plane that is between the lateral and medial ends of the surfacing portion. 
     
     
         3 . The tibial resurfacing implant of  claim 2 , wherein the plane along which the keel extends is substantially equidistant from the lateral and medial ends of the surfacing portion. 
     
     
         4 . The tibial resurfacing implant of  claim 1 , wherein the keel comprises a first end portion in contact with the tibia-facing surface and a second end portion that is located opposite to the first end portion, wherein the cylindrical element is located at the second end portion. 
     
     
         5 . The tibial resurfacing implant of  claim 1 , wherein the keel with the cylindrical element is configured to affix the tibial implant structure to a tibia without requiring a cement preparation. 
     
     
         6 . The tibial resurfacing implant of  claim 1 , wherein the cylindrical element has annular notches or extrusions. 
     
     
         7 . The tibial resurfacing implant of  claim 6 , wherein the annular notches or extrusions are between 0.1 and 0.2 mm relative to a diameter of the cylindrical element. 
     
     
         8 . The tibial resurfacing implant of  claim 1 , wherein a diameter of the cylindrical element at the anterior end of the keel approximates a diameter of the cylindrical element at the posterior end of the keel. 
     
     
         9 . The tibial resurfacing implant of  claim 1 , wherein a diameter of the cylindrical element at the anterior end of the keel is greater than a diameter of the cylindrical element at the posterior end of the keel. 
     
     
         10 . The tibial resurfacing implant of  claim 1 , wherein a distance between the tibia-facing surface and the cylindrical element at the posterior end of the keel is greater than a distance between the tibia-facing surface and the cylindrical element at the anterior end of the keel. 
     
     
         11 . The tibial resurfacing implant of  claim 10 , wherein a difference between the distance between the tibia-facing surface and cylindrical element at the anterior end of the keel and the distance between the tibia-facing surface and the cylindrical element at the posterior end of the keel is between about 0.2 mm and 0.5 mm 
     
     
         12 . The tibial resurfacing implant of  claim 1 , wherein the femur-facing surface has a dished morphology. 
     
     
         13 . The tibial resurfacing implant of  claim 1 , wherein the surfacing portion has a thickness of about 5 mm or less at its thinnest point. 
     
     
         14 . The tibial resurfacing implant of  claim 1 , wherein the surfacing portion has a thickness of no more than about 2 mm to allow for mounting the surfacing portion along relatively strong bone tissue of a proximal region of a tibia to provide better strength at an interface of the tibia and the tibia-facing surface. 
     
     
         15 . The tibial resurfacing implant of  claim 1 , wherein the surfacing portion is tapered relative to the keel. 
     
     
         16 . The tibial resurfacing implant of  claim 15 , wherein the surfacing portion is tapered along a frontal plane, the frontal plane being defined with respect to a patient in whom the tibial implant structure is implanted. 
     
     
         17 . The tibial resurfacing implant of  claim 15 , wherein the surfacing portion is tapered along a sagittal plane, the sagittal plane being defined with respect to a patient in whom the tibial implant structure is implanted. 
     
     
         18 . The tibial resurfacing implant of  claim 15 , wherein the surfacing portion is tapered along:
 a frontal plane, the frontal plane being defined with respect to a patient in whom the tibial implant structure is implanted, and   a sagittal plane, the sagittal plane being defined with respect to the patient.   
     
     
         19 . A method for implanting a tibial implant structure on a tibia of a patient, the method comprising:
 removing a portion of a condyle of the tibia to create a resected tibial condyle for mounting the tibial implant structure, the tibial implant structure comprising:   a surfacing portion with a tibia-facing surface and a femur-facing surface, wherein the surfacing portion is substantially planar,   a keel extending from the tibia-facing surface of the surfacing portion in a direction substantially perpendicular to the surfacing portion, wherein the keel comprises a substantially planar element, and
 a cylindrical element extending from an anterior end of the keel to a posterior end of the keel; 
   creating a groove along the resected tibial condyle to accommodate the keel of the tibial implant structure;   creating an aperture along a length of the groove to accommodate the cylindrical element of the tibial implant structure; and   mounting the tibial implant structure on the resected tibial condyle, wherein: the surfacing portion is caused to interface with a surface of the resected tibial condyle, the keel is caused to be disposed within the groove, and the cylindrical element is caused to be disposed within the aperture.   
     
     
         20 . The method of  claim 19 , wherein the surface of the resected tibial condyle is caused to be sloped along:
 a frontal plane, the frontal plane being defined with respect to a patient in whom the tibial implant structure is implanted, or   a sagittal plane, the sagittal plane being defined with respect to the patient.