Title of Invention	A KNEE JOINT ASSEMBLY FOR BODY IMPLANT
Abstract	This invention relates to a flexible knee joint implant for human body. It consists of an upper rod and a lower rod. The upper rod terminates in an annular cavity. The lower rod has a projection which lies in flush with this annular cavity. These two parts are held together at the knee area with the help of hinged fixing means such as the pin and screw types.

Full Text

This invent ion relates to a knee .joint assembly for body implants and is particularly but not exclusively related to knee Joints between femur and tibia ferula of the human leg. Total knee replacement often becomes necessary in the event of severe knee joint damage either due to injury or disease. The implanted knee joint must be strong enough to bear the body weight of the individual and must be reasonably flexible for providing normal ambulation. At the same time the implant must be compatible with the body and must not be too heavy. An object of this invention is to develop a knee point assembly which provides adequate flexibility, which is ■ biocompatible, and is comfortable to the user. The thigh bone, femur of the human body has a hole running right through which has an elliptical cross section. The bone, faba of the lower leg also has a hole therein with elliptical cross section. The knee joint assembly developed by us has two solid reds of elliptical cross section flexibly joined together at the knee area The rods may be made of any gametal or alloy. However, a titanium alloy having extra low interstitial properties is preferred. The preferred titanium alloy has the following watts composition. Aluminium 5.5 to 6.5, Vanadium 3.5 to 4.5, Carbon 0.08 max. Nitrogen 0.03 max. Hydrogen 0.0125 max. Oxygen 0,13 max. Iron 0,25 max and the balance being titanium. This alloy may also contain extra - low interstitial elements like oxygen. The upper rod which goes into the fearer bone when asseitiblsd is tapered and one end of which is provided with an annular cavity to accept the lower part of the assembly. The lower part consists of a solid rod which may be tapered towards one end. A projection is provided on the unhampered end of the lower rod and is intended to correspond to the annular cavity of the upper rod the projection lies in flush with the annular cavity and is flexibly joined with the upper part of the assembly through the walls of the annular cavity provided therein. The taper of the upper rod and lower rods may be in the range of 12mBi 0 to 7 mn 0 . Any conventional flexible means may be used for Joining the projection of the lower part within the upper part. A cylindrical pin provided with a locking screw is one such embodiment. The looking arrangement may also contain a hinge pin and a key screw. The knee joint assembly for body implant according to this invention comprises an upper rod and a lower rod, both of elliptical cross section flexibly joined at the knee area, the lower end of said upper rod being provided with an annular cavity, the upper end of said lower rod having an outward projection that corresponds to and lies In flush with the annular cavity of said upper rod and means for flexibly joining said projection of the lower rod with the Walla of the annular cavity of the upper rod. This invention will now be described with reference to Figure 1 of the accompanying drawings which represents a line diagram of the knee joint. Reference letter F stands for the femur bone of human body while the letter T represents Tibia. The upper rod and the lower rod of the knee joint assembly are shown by U R and L B respectively. The annular cavity of the ripper rod is shown by letters AC while the outer wails that surround the cavity is shown by OW. The projection on the lower rod is shown by the letter P. Means for flexibly joining the two parts at the knee area is shown by HP which is a hinge pin which may be cylindrical. LS represents the locking screw which locks the projection within the annular cavity. KS shows the key screw which may be used for adjusting the flexibility. During knew transplant the upper rod is inserted into the femurs and the lower rod into the tibia. The elliptical cross section of these rods helps the implants to snugly fit into the annular cavity when implanted. The projection of the lower rod is housed within the cavity of the upper rod and is fixed thereto with the help of a cylindrical pin, lock nut and key screw. This arrangement prevents undesirable rotating movements of the implant while allowing necessary flexibility to enable the person with the implant to walk with minimum discomfort. Though this invention has been described hereinabove with a specific embodiment, obvious equivalents and modifications known to persons skilled in the art are within the scope and ambit of the appended claims. WE CLAIM: 1. A knee joint assembly for body implant comprising an upper rod (UR) and a lower rod (LR) both of elliptical cross section, flexibly joined at the knee area, the lower end of said upper rod being provided with an annular cavity (AC) , the upper end of the lower rod having an outward projection (P) that corresponds to and lies in flush within the annular cavity of said upper rod, and means (LS, HP, KS) for joining said projection of the lower rod within the walls of said annular cavity of the upper rod. 2. The knee joint assembly for body implant as claimed in claim 1 wherein both the upper and lower rods are tapered, the taper being in the range of 12mm 0 to 7mm 0. 3. The knee joint assembly for body implant as claimed in claims 1 and 2 wherein the said rods are made of a metal or an alloy. 4. The knee joint assembly for body implant as claimed in claim 3, wherein said rods are made of a titanium containing alloy consisting of 5.5 to 6.5 of Al, 3.5 to 4.5 of vanadium, 0.08 max of carbon, 0.03 max of nitrogen, 0.0125 max of hydrogen, 0.13 max of oxygen, 0.25 max of Fe, the balance being titanium all ranges expressed by weight percentage. 5. The knee joint assembly for body implant as claimed in claims 1 to 4, wherein said means for flexibly joining the upper rod and the lower rod consists of a cylindrical pin, hinge pin, and a locking screw. 6. The knee joint assembly for body implant as claimed in claims 1 to 5, wherein said means for flexibly joining the upper and lower rods has a key screw.

Documents:

1118-mas-1999 abstract-duplicate.pdf

1118-mas-1999 abstract.pdf

1118-mas-1999 claims-duplicate.pdf

1118-mas-1999 claims.pdf

1118-mas-1999 correspondence-others.pdf

1118-mas-1999 correspondence-po.pdf

1118-mas-1999 description (complete)-duplicate.pdf

1118-mas-1999 description (complete).pdf

1118-mas-1999 drawings-duplicate.pdf

1118-mas-1999 drawings.pdf

1118-mas-1999 form-1.pdf

1118-mas-1999 form-19.pdf

1118-mas-1999 form-26.pdf

1118-mas-1999 form-3.pdf

1118-mas-1999 form-4.pdf