FOAM CUSHION FOR INSERTION IN A KNEE JOINT
A cushion is disclosed for insertion in a patient's knee joint to serve as a buffer between a patient's femur and tibia. The cushion is filled with a substantially incompressible fluid, which can be a foam or a gel or a liquid, like water, which is capable of supporting the entire weight of the patient's body. The cushion is preferably made from a flexible material that allows relative movement between the patient's femur and tibia, while resisting rupture as it supports these two bones as they are moving relative to one another as the knee joint is flexed, bent or extended.
1 . A cushion adapted to be implanted in a patient's knee joint between the patient's femur and tibia bones, the cushion comprising: a pocket made from a flexible material, and a fluid filling the interior of the pocket, the pocket being sized to fit in the space between the patient's femur and tibia bones.
2 . The cushion of claim 1 , wherein the pocket is adapted to accommodate two interior crucible ligaments extending between the patient's femur and tibia bones.
3 . The cushion of claim 1 , wherein the cushion substantially has a size corresponding to the menisci originally in the patient's knee joint between the patient's femur and tibia bones.
4 . The cushion of claim 1 , wherein the fluid is a substantially incompressible fluid.
5 . The cushion of claim 4 , wherein the substantially incompressible fluid is water.
6 . The cushion of claim 1 , wherein the fluid is a foam.
7 . The cushion of claim 1 , wherein the fluid is a gel.
8 . The cushion of claim 1 , comprising an opening adapted to accommodate two interior crucible ligaments, wherein said opening is placed substantially in the center of the cushion through which the ligaments pass.
9 . The cushion of claim 1 , comprising a narrow section adapted to accommodate two interior crucible ligaments in a narrow center section of the cushion, that passes between the ligaments, so that the cushion is shaped substantially like a bow tie.
10 . The cushion of claim 1 , wherein the flexible material is a polymer type of material.
11 . The cushion of claim 1 , wherein the cushion is comprised of a plurality of interior pockets filled with the fluid and isolated from another so that a rupture of one pocket results in the fluid draining from the ruptured pocket and not from the other pockets comprising the plurality of pockets.
12 . The cushion of claim 1 , wherein the cushion has a first fixating section for attaching the cushion to the bottom of the femur at least a first point of attachment and a second fixating section for attaching the cushion to the top of the tibia at least a second point of attachment so that, as the femur moves relative to the tibia when a patient bends his or her knee joint, the positioning of the first and second points of attachment are caused to shift relative to one another to accommodate a change in orientation between the femur and the tibia caused by the bending of the patient's knee joint.
13 . The cushion of claim 1 , wherein the cushion further comprises a valve arrangement for adding and removing fluid from the cushion to thereby change the level of pressure in the cushion and thereby the support provided by the cushion with respect to the patient's knee bones.
14 . The cushion of claim 13 , further comprising an apparatus adapted to be implanted in a patient that is connected to the valve arrangement for adding fluid to, or removing fluid from, the cushion.
15 . The cushion of claim 14 , wherein the apparatus is comprised of: an internal control unit adapted to be implanted in the patient, a fluid reservoir adapted to be implanted in the patient from which fluid is obtained or to which fluid is added for changing the level of fluid in the cushion, and a motor pump unit adapted to be implanted in a patient for transferring fluid from the fluid reservoir to the cushion and from the cushion to the fluid reservoir to thereby change the pressure in the cushion.
16 . The cushion of claim 1 , further comprising a second cushion positioned between the cushion and either the femur or the tibia bones so that two cushions are positioned between said bones, wherein the cushion has a first fixating section for attaching the cushion to the bottom of the femur at least a first point of attachment and the second cushion has a second fixating section for attaching the second cushion to the top of the tibia at least a second point of attachment.
17 . The cushion of claim 16 , further comprising first and second flat metal plates positioned between the cushion and the second cushion, the first and second metal plates being attached to the cushion and the second cushion so that the plates slide relative to one another as the orientation between the femur and the tibia changes as the patient bends his or her knee.
18 . The cushion of claim 17 , wherein the first and second metal plates are fixed relative to one another so that the first and second points of attachment are caused to shift relative to one another to accommodate a change in orientation between the femur and the tibia caused by the bending of the patient's knee joint.
19 . The cushion of claim 13 , further comprising a pressure sensor connected to the cushion that determines the level of pressure in the cushion.
20 . The cushion of claim 15 , further comprising an external control unit including an external source of energy and a wireless remote control transmitting to the internal control unit a control signal generated by the external source of energy.
21 - 31 . (canceled)