Title of Invention

"BI-CENTRIC HIP DEVICE"

Abstract

The invention relates to a bi-centric hip system having two components viz. a cup being made from metal and inner lining of cup being made up from ultra high molecular weight polyethylene or ceramic and second component called prosthesis which has got a head and a stem ; head being of predetermined size ,being made up from steel or ceramic and a stem with collar and neck , stem being made of steel or titanium, coated with or without hydroxyappetite ;can be articulated at the time of surgery with the help of a jig or it can come as a single piece. System can be disarticulated with disarticulated jig. Fig: F1G1

Full Text

BI-CENTRIC HIP SYSTEM IS A HIGHLY VERSATILE SYSTEM TO SATISFY PATIENTS SURGICAL AND NURSING NEEDS CLINICAL INDICATIONS PRIMARY Fractures of the proximal femur. Non-unions of proximal femoral fractures. Aseptic necrosis of the femoral head™ SECONDARY Qsteo,, rheumatoid, and post-traumatic arthritis of the hip with minimal distortion of the acetabulum. Salvage of failed total hip arthroplasty, which will be used to marry the cup and the ball. Another jig will be used to un-match them if it. is needed. The greatest advantage of this system is that after serving for a couple of years in the human body when the system fails usually the cup compo-nent then it can be converted into total hip by reoperating. In the second surgery the cup will be dismantled and thrown out instead a new cup of the total hip system will be fitted into the ascetabu-lum with the help of cement, and the already exist-ing prosthesis with 22mm diameter head will be married to the new cup, thus reducing the time of surgery as well as the cost to a great extent. The presently designed system has got certain advantages over the already existing bipolar hip prostheses, The two component of the bipolar already existing are not dismantable. The seating angle of the prosthesis is unac-ceptably low so, the surgeon have to cut a lot of calcarbone which is so disadvantageous to the patient as far as the long term results are con-cerned . The long term results are not good because of the stiffness that develops probably due to abnor-mally high stress generated at. the acetabular cartliage and the metallic cup level as well as the metallic head and the polyethylene cup. The inner ball of the presently existing bipolar has got a diameter of 28mm which is diffi¬cult to marry with the commonly existing cup of the total hip system which has got a 22.5mm inner diameter. The present existing bipolar system cannot be converted into a total hip system. Brief description of the accompanying drawings: Fig 1 represents the right hand side view of the Bi-Centric Hip device. Fig 2 represents the front view of the Bi-Centric Hip device. Fig 3 represents the view of the Disarticulating Jig Fig 4 represents the view of the Articulating jig. Fig 5 represents the view of the hollow hemispherical cup. Accordingly the present invention describes about A Bi-centric hip device comprising (a) A stem portion (endoprosthesis) having a distal end (1) of a predetermined length which is straight and an opposed proximal end(2) which is arcuately shaped; the said proximal end (2) having a collar portion (3); said collar portion having a neck of reducing diameter; a head portion (4) which is an extension of the said neck portion; the said head portion being in the shape of a spheroid having a predetermined diameter; the said collar [portion having a groove of a predetermined radius for inserting the said stem into the hollow bone structure by way of slight hammering; the said arcuated potion (2) having at least two through holes of predetermined radius at predetermined positions for removing the said stem from the hollow bone structure; the said proximal end (2) being so arcuated such that the angle formed between the straight distal end(l) of the stem and the opposed proximal end(2) is about 138° and the angle between the collar (3) and the straight distal end(l) is about 40° -50° preferably 45°; (b) A bi-centric hemispherical hollow cup (6) having a predetermined diameter and predetermined thickness; the inner portion of the hemispherical hollow cup having a layer of a suitable material of a predetermined thickness; the said layer(5) being arcuately shaped so that the resulting obstruction between the said layer and the portion between the said neck and head portion is minimal; the said cup being adapted to be inserted on to the head portion (4) of the stem in a manner wherein the center of the said head portion (4) and the center of the said hollow cup(6) is offset by about 2mm providing greater movement of the said head portion(4) in the said cup (6) as compared to the movement of the hollow cup(6) itself. Accordingly the present invention also describes about a disarticulating jig for dismantling the bi-centric hip device comprising a rod portion (8) of a predetermined length; an arcuated frame portion (11) shaped to accommodate the head portion of the said stem; a threaded spindle (10) attached to a screw (9); the said spindle having soft pads (12) wherein the said frame portion (11) is adjusted over the head portion of the stem and the spindle is moved through screw(9) to hold the said head portion. Also the present invention describes about an articulating Jig for fixing the Bi-centric hip device comprising two leg portions (14,15) having a straight distal end(17) and proximal ends(18, 19) which are arcuately shaped; the said legs (14, 15) being pivoted at a point (16) closer to the proximal end; the said proximal end (18,19) being so shaped so as to properly hold the Bi-Centric hip device on the soft pads(12). I claim 1. A Bi-centric hip device comprising a) A stem portion (endoprosthesis) having a distal end (1) of a predetermined length which is straight and an opposed proximal end (2) which is arcuately shaped; the said proximal end (2) having a collar portion (3); said collar portion having a neck of reducing diameter; a head portion (4) which is an extension of the said neck portion; the said head portion being in the shape of a spheroid having a predetermined diameter and set collar portion having a groove of a predetermined radius for inserting the said stem into the hollow bone structure by way of slight hammering; the said arcuated potion (2) having at least two thorough holes of predetermined radius at predetermined position for removing the said stem from the hollow bone structure; the said proximal end (2) being so arcuated such that the angel formed between the straight distal end(l) of the steam and the opposed proximal end(2) is about 138° and the angle between the collar (3) and the straight distal end(l) is about 40°- 50° preferably 45° j b) A bi-centric hemispherical hollow cup (6) having a predetermined diameter and predetermined thickness; the inner portion of the hemispherical hollow cup having a layer of a suitable material of a predetermined thickness; the said layer (5) being arcuately shaped so that the resulting obstruction between the said layer and the portion between the said neck and head portion is minimal; the said cup being adapted to be inserted on to the head portion (4) of the stem in a manner wherein the center of the said head portion (4) and the center of the said hollow cup(6) is offset by about 2mm providing greater movement of the said head portion (4) in the said cup (6) as compared to the movement of the hollow cup (6) itself. 2. A device as claimed in claim 1 wherein the said stem and said hollow cup are made up of non-corrosive material preferably steel ( 3. A device as claimed in claim 1 wherein the said layer (5) is made up of Ultra High Molecular Weight Polyethylene (or ceramic) 4. A disarticulating jig for dismantling the bi-centric hip device as claimed in claiml comprising a rod portion (8) of a predetermined length; an arcuated frame portion (11) shaped to accommodate the head portion of said stem; a threaded spindle (10) attached to a screw (9); the said spindle having soft pads (12) wherein the said frame portion (11) is adjusted over the head portion of stem and spindle is moved through screw (9) to hold the said head portion. 5. An articulating Jig for fixing the Bi-centric hip device a s claimed in claim 1 comprising two portions (14,15) having a straight distal end (17) and proximal e.ids (18,19) which are arcuately shaped; the sad legs (14,15) being pivoted at point(16) closer to proximal end; the said proximal end (18,19) being so shaped so as to properly hold the Bi-Centric hip device on the soft pads(12). 6. A Bi-Centric hip device substantially as herein described with reference to the accompanying drawings.

Documents:

125-del-1999-abstract.pdf

125-del-1999-claims.pdf

125-del-1999-correspondence-others.pdf

125-del-1999-correspondence-po.pdf

125-del-1999-description (complete).pdf

125-del-1999-drawings.pdf

125-del-1999-form-1.pdf

125-del-1999-form-13.pdf

125-del-1999-form-19.pdf

125-del-1999-form-2.pdf

125-del-1999-form-62.pdf

abstract.jpg