Title of Invention

PROXIMAL ULNA PROSTHESIS WITH ELBOW JOINT

Abstract

An surgically implantable Proximal ulna prosthesis with elbow joint consists.of the distal humeral stem with condylar component, proximal ulnar shaft with stem, collared bushes, pivot pin and pivot pin fixing screw. The distal humeral stem has an inter-medullary stem at its upper end and the lower part expands to form the condylar head which has a central notch anteriorly formed by two walls, the floor being formed by a radial groove which accommodates the upper circular portion of the proximal ulnar component. The collar bushes and the pivot pin are fitted between the walls of th~ condylar component and the proximal ulnar shaft. The proximal ulnar component continues as the shaft, which replaces the upper part of the ulna and ends in the intramedullary stem. All the components are assembled together by the pivot pin and pivot pin fixing screw, permitting a movement of 0 -1700.

Full Text

Field of invention This invention in general relates to the field of medical technology. Further, this invention relates to a novel custom-built endoprosthesis namely the Proximal Ulna Prosthesis with Elbow Joint. More particularly this invention relates to custom-built endoprosthesis Elbow Joint with Ulna. Introduction Management of patients with musculoskeletal neoplasms has always been one of the most challenging areas in oncology. Prior to 1970, almost every patient with a primary malignant tumour of musculoskeletal system would have any surgical treatment. They would not have adjuvant chemotherapy or irradiation and surgical treatment was almost an amputation with a five-year survival rate of 20%. For benign lesions such as Giant Cell Tumours, the treatment was curettage with 40-60% recurrence rate. Patients with painful metastatic lesions were managed palliatively until they were mercifully relived by death. Prior Art Technique and Practice The conventional treatment for bone tumours over the years has been amputation, which is surgical removal of the affected part of the body. Amputation led to severe disability and psychological problems. The patient was made to lose not only part of the physical human body, but also a part of the personality of the patient. By the advent of limb salvage, the technique of removing the tumour only and saving the limb of the patient was developed. The aim of limb salvage in bone tumour management is to eradicate the disease, retain the integrity of the skeletal system and preserve the limb with useful functions using metallic prosthesis. The early methods of reconstruction after limb salvage used the patient's own bone from another part of the body, but were associated with severe disability due to the lack of knee motion. The technique of endoprosthetic replacement revolutionized limb salvage by providing a method of reconstruction that provides stability and mobility. The endoprostheses that is used after excision of bone tumours around the Elbow Joint differs from other joint replacement prosthesis because of the amount of mobility required at the site for good function. The prosthesis is fabricated according to the anatomical dimensions of the patient and is therefore termed as the Custom Prosthesis. The custom prosthesis was designed by us to meet the anatomical and functional demands after excision of bone tumours. Different types of Custom Prosthesis have been developed by us to replace bone defects after limb salvage surgery for bone tumours of the elbow, distal radius, distal femur (Thigh bone) shoulder joint (Proximal Humerus) proximal tibia (Leg bone) and sholder joint (Proximal Humerus). Our Patent No. 198872, which has been awarded, is Proximal Tibial Prosthesis with a Pivotal Hinge Mechanism our Patent No: 198869, is a Proximal Tibial Prosthesis with Trust Bearing Pad Mechanism. Our Patent No. 196333 is Distal Femoral Prosthesis with Thrust bearing Pad and Oscillating Hinge Mechanism and our Patent application No: 898/MAS/2001, which has also been submitted, is a Distal Femoral Prosthesis with Pivotal Hinge Mechanism. Our Patent No: 196333, which has also been awarded, is a Distal Femoral Prosthesis With Thrust Bearing Pad And Rotating Axis Mechanism. Even though all these patent applications are for prostheses around the knee joint, the anatomical part replaced by Patent Nos: 198872 and 198869 covers the region of Knee and the accompanying bone below the knee (Proximal Tibia), whereas the patent application No: 898/MAS/2001, and Patent No: 196333 replaces the knee joint and the adjoining thigh bone (Distal Femur). Our other similar patents that have been awarded are Patent No: 201520 for the Distal Tibial Prosthesis with ankle Joint, and the Patent No. 202044 for Distal Radial Prosthesis with Wrist Joint, This patent application that is being filed is the Proximal Ulnar Prosthesis with Elbow joint which surgically replaces the upper part of the ulna (forearm bone) and does not have an oscillating mechanism, whereas the patent application No 1240/CHE/2004, Distal Humerus and Elbow joint with Oscillating Mechanism, replaces the lower part of the humerus (arm bone) and has an oscillating mechanism. All the other applications except 1240/CHE/2004 are for prosthesis that replace other anatomical regions of the body and not the elbow joint. Objects of Invention It is the primary object of the invention to invent and construct a novel - Proximal Ulna Prosthesis with Elbow Joint. It is yet another object of the invention to invent and construct a novel endoprosthesis Proximal Ulna Prosthesis with Elbow Joint, which is unique. It is yet another object of the invention to invent and construct a novel endoprosthesis Proximal Ulna Prosthesis with Elbow Joint, which mimics the physiological action of the elbow joint. It is yet another object of the invention to invent and construct a novel endoprosthesis Proximal Ulna Prosthesis with Elbow Joint, which would retain the functional aspects of the elbow joint with ulna. It is yet another object of the invention to invent and construct a novel endoprosthesis - Proximal Ulna Prosthesis with Elbow Joint, which would take care of the structural loading which were encountered by the elbow joint before the lesions. It is yet another object of the invention to invent and construct a novel endoprosthesis - Proximal Ulna Prosthesis with Elbow Joint, which matches in, profile the anatomic region of the distal humerus, elbow and proximal ulna. It is yet another object of the invention to invent and construct a novel endoprosthesis - Proximal Ulna Prosthesis with Elbow Joint, which is economical. It is yet another object of the invention to invent and construct a novel endprosthesis - Proximal Ulna Prosthesis with Elbow Joint, which is safe in usage. It is yet another object of the invention to invent and construct a novel endoprosthesis - Proximal Ulna Prosthesis with Elbow Joint, wherein the said device is provided with hinge mechanism to impart articulating motion of the elbow joint. Further objects of the invention will be clear from the following description. BRIEF DESCRIPTION OF THE DRAWINGS The following specification will describe in detail with reference drawings accompanying the specification. The nature of the invention and the manner in which it is to be performed is clearly and sufficiently described in the complete specification. The final portion of the complete specification ends with a statement of claims, which defines the invention. Drawing sheet No: 1 Front view - Proximal ulnar prosthesis with elbow joint. Drawing sheet No:2. Folded side view - Proximal ulnar prosthesis with elbow joint. Drawing sheet No:3. Exploded front view - Proximal ulnar prosthesis with elbow joint. Drawing sheet No:4. 3D view - Proximal ulnar prosthesis with elbow joint. Basic components of the device are designated by numerals in the illustrated drawings and are referred in the description of the complete specification. The designations of various parts of the device are as follows. LEGEND OF PARTS This Proximal Ulna Prosthesis with Elbow Joint as the following components as per drawing sheet No: 1 to 4 I. Distal humeral stem with condylar component - Fig.3 - (1-10) II. Proximal Ulna Component - Fig.3 & 4 - (11 - 20) III. Collared Bushes - Fig.3 - (24-28) IV. Pivot Pin - Fig.3 - (29-3 V V. Locking Screw - Fig.3 - (32 - 35) All the components are made of surgical stainless steel of AISI - 316L, 317L Grade or Titanium alloy of ASTM - B 348, Grade 5, except the collared bushes, which are made of Ultra High Molecular Weight Polyethylene provided to avoid metal-to-metal friction providing smooth movements and preventing wear and tear. DETAILED DESCRIPTION OF INVENTION I. Distal Humeral Stem with Condylar Component (1-10) The Distal humeral stem with condylar component (a) consists of an intramedullary stem and condylar head. The intramedullary stem is present at the upper end and forms the bone-anchoring component. It is tapered (2 & 3 of fig.3) with a matted finish surface and is provided with longitudinal grooves (1 of fig.3) along its length, for fixing into the cement in the intramedullary canal of the humerus. The lower part of the intramedullary stem (3 of fig.3) ends on the upper flat surface of the condylar region. This surface comes into contact with the distal humeral bone when the prosthesis is assembled and has troughs (10 of fig.3) for integration with the bone cement. The distal humeral component then expands into the condylar component (4-9 of fig 3). The anterior surface of the condylar component has a notch placed centrally and two circular walls ( 7 of fig.3), which project anteriorly and have a central hole (6 of fig 3 & 4), and have a semi circular groove (8 of fig.3), to accommodate the upper end of the ulnar component and ends as the free inferior surface of the condylar component (9 of fig.3), which acts as a stopper when the joint is fully extended up to 0 °. II. Proximal Ulnar Component: (11 - 20) The ulnar component (b) of fig.l, 2,3 and 4 has a shaft, which is oval in shape (11 of fig.l-4). The upper end of the shaft, expands into a circular shape which projects anteriorly, and has a central hole (20 of fig.3, 4). The anterior curved surface of the upper circular part of the proximal ulnar component has a central counter hole with threads, ( 19 of fig 4), which opens into the central hole (20 of fig 4) in the upper of the ulnar component. The lower part of the ulnar component expands into a collar (12 of fig.3), the lower surface of which forms the circular platform for contact with the cut end of the ulnar bone. This surface has grooves (13 of fig.3) which serve to integrate with the cement at the junction with the cut end of the ulna. From the platform arises the intramedullary stem (14 of fig.3), which anchors, into the cement in the medullary canal of the ulna. This stem is tapered (16 of 3) and has a matted finish surface with three longitudinal grooves (15 of 3) for anchorage within the cement in the medullary canal of the ulna. ffl. Collared bushes ( 24 - 28) The collar bushes (c) are in the shape of a hollow cylinder with a collar at one end. The surface of the cylindrical portion (26 of fig.3) is in contact with the inner surface of the holes (6 of fig.l) in the two anterior projecting circular walls of the condylar component (7 of fig.3) and the inner surfaces of the cylinder bore of the collar bush (27 of fig.3) come into contact with the outer surface (29 of fig.3) of the pivot pin. The outer surface of the collar (24 of fig.3) is in content with the inner surfaces of the anterior circular walls of the condylar component and the inner surface of the anterior circular walls of the condylar component and the inner surface of the collar (25 of fig.3) comes into contact with the outer surfaces of the upper circular portion (18 of fig.3) of the ulnar component (b of fig.3). The free edge of the collar (20 of fig.3) is visible between the anterior circular extensions walls of the condylar component (a of fig. 1) and the upper circular portion (18 of fig.3) of the proximal ulnar component (b of fig.3). IV. Pivot Pin (29 - 31) The pivot pin (d of fig. 1-4) has a smooth cylindrical shaft (31 of 3). The anterior aspect of the middle of the pivot pin has a hole (29 of fig.3) for the distal end of the pivot pin fixing screw (e of fig 3) to engage. The two ends of the pivot pin have a longitudinal slot (30 of fig 3) to indicate the central counter hole (19 of fig 4). The two ends of the pivot pin seat in the bore of the collar bush, which seated in the walls of the part (a) of the condylar component (7 of fig.3) and the central part goes through the ulnar component and is locked by the locking screw. This enables the unit to function as a single assembly permitting free movement. V. Pivot Pin Fixing Screw (32 - 35) The pivot pin fixing screw (e of fig.3) has a head (33 of fig.3) with a slot (35 of fig.3). The under portion of the head (34 of fig.3) is flat, from which the threaded part of the screw (32 of fig.3) arises. The thread position of screw fits into the threaded narrower portion of the hole (19 of fig.3) in the proximal ulnar component. When the screw is fully tightened, the head of the screw lies flush with the counter bore of the groove, threaded part the screw engages with the threads in the lower narrower portion of the groove and the tip of the screw engages through in the middle of the anterior aspect of the pivot pin (29 of fig.3). The either ends of the pivot pin are provided with a slot (35 of fig.3) to align the through in the pivot pin with the counter hole. The pivot pin fixing screw can pass through the hole thereby locking the pivot pin with the proximal ulnar component. Thus the condylar component, collared bushes, proximal ulnar component with pivot pin in to a full assembly. The elbow joint mechanism is formed by the distal humeral component (I of Fig 3), ulnar component (b) of 1-5, collar bushes (c) of fig. 1-5 Pivot pin (e of 1-5) and pivot pin-fixing screw. The collar bushes fit into the holes (6 of fig.3) in the distal humeral component and the semicircular grooves accommodate the collars of the bushes ( 28 of fig 3). The upper circular portion of the proximal ulnar component ( 20 of fig 3 & 4) seats between the inner surface of the two collared bushes( 25 of fig 3). The pivot pin posses through the groove in the collar bush of side (27 of fig..3) and then through the hole in the upper circular portion of the proximal ulnar component (20 of 3,4) and then through the hole in the collar bush of the opposite side. The pivot pin is held in place by the pivot pin fixing screw (e of fig.3), which passes in to the groove in the anterior part of the proximal ulnar component (19 of fig.3) and engages in the trough in the anterior aspect of pivot pin. All the components are therefore integrated into a single assembly unit held together by the pivot pin, forming the elbow joint. The elbow joint permits a movement of 0-170°. When the joint is fully extended, the upper part of the posterior aspect of the ulnar component comes into contact the free inferior portion of the distal humeral component (19 of fig 3). The flexion of the elbow beyond 170° is limited by contact between the anterior surface of the arm and the forearm. claim: 1. An surgically implantable Proximal ulna prosthesis with elbow joint, the invention characterized herein consists of the distal humeral stem with condylar component, which has an intramedullary stem at one end and the other end expands to form the condylar head which has a central notch anteriorly formed by two walls arising from the base and having a concentric bore on each other to accommodate the collar bushes and the pivot pin, the floor of the condylar component being formed by a radial groove also concentric with that of the axis of the pivot pin, which accommodates the radial portion on the hub of the proximal ulnar component, which has a cylindrical shaft to replace the proximal part of the ulna and has the intramedullary stem on the other end, all the components being held together by the pivot pin and locked by a pivot pin fixing screw which enters the head of the ulnar component radially and positioned into the blind radial hole of the pivot pin, permitting the flexion required by the elbow. * 2. Proximal ulna prosthesis with elbow joint as claimed in Claim 1, wherein the distal humeral stem expands into the condylar component, which structurally resembles the lower part of the humeral bone. 3. Proximal ulna prosthesis with elbow joint as claimed in Claim 1, wherein the condylar head has two projecting walls anteriorly and the floor of the walls, has a radial groove to accommodate the head of the ulnar component and the collar of the collar bush. 4. Proximal ulna prosthesis with elbow joint as claimed in Claim 1, wherein the condylar head has a semi circular groove anteriorly, the free inferior edge which comes into contact with the posterior surface of the ulnar stem at the position of full extension (0°), thereby preventing further extension of the joint. 5. Proximal ulna prosthesis with elbow joint as claimed in Claim 1, wherein head of the proximal ulnae component is in the form of a hub, which has a central hole to accommodate the pivot pin. 6. Proximal ulna prosthesis with elbow joint as claimed in Claim 1, wherein the collared bushes fit into the holes in the two raised walls on the anterior surface of the condylar component. 7. Proximal ulna prosthesis with elbow joint as claimed in Claim 1, wherein the collared bushes have a axial bore to permit the pivot pin to pass through. 8. Proximal ulna prosthesis with elbow joint as claimed in Claim 1, wherein the proximal ulnar component is in the form of an oval shaft to replace the proximal portion of the ulna. 9. Proximal ulna prosthesis with elbow joint as claimed in Claim 1, wherein the pivot pin links the various components of the joint into a single assembly. 10. Proximal ulna prosthesis with elbow joint as claimed in Claim 1, wherein the pivot pin fixing screw passes radially through the head of the proximal ulnar component and engages in the blind hole the pivot pin, therefore preventing movement of the pivot pin. Dated this 10th day of November 2004.

Documents:

1369-che-2004-abstract.pdf

1369-che-2004-claims.pdf

1369-che-2004-correspondnece-others.pdf

1369-che-2004-correspondnece-po.pdf

1369-che-2004-description(complete).pdf

1369-che-2004-drawings.pdf

1369-che-2004-form 1.pdf

1369-che-2004-form 19.pdf

1369-che-2004-form 3.pdf