1. TITLE OF INVENTION:
EXPANDING MECHANISM IN PROXIMAL FEMUR PROSTHESIS
2. FIELD OF INVENTION:
This invention generally relates to the field of medical technology. Further this invention relates to a novel custom built endo prosthesis with expandable mechanism in proximal femur prosthesis, more particularly for pediatric and young patients who suffered from length shortage during growth.
3. BACKGROUND OF INVENTION:
Management of patient with musculoskeletal neoplasm has always been one of the most challenging areas in oncology. Prior to 1970, patient with a primary malignant tumor of musculoskeletal system would have no surgical treatment except amputation. Later on the custom built prosthesis and mounted prosthesis are introduced to replace the affected bone. This prosthesis is give suitable for adults where shortage of height not required near future.
The pediatric and young patients are suffered from length shortage during growth due to no growth in the prosthesis portion which is fixed into the patient's body. Because of this there is an imbalance in the length in the leg or hand and over period of time, length of one leg or hand become longer than the other one. A person fixed with prosthesis in the early age need to suffer this deformity throughout life or otherwise once again an old prosthesis shall be replaced by a new one having the required length. Prosthesis replacement is painful, expensive and it is not advisable. Therefore it is an object of the present invention to provide a prosthesis in which a length adjustment mechanism is incorporated to increase the length of the prosthesis whenever required.
The length of the prosthesis can be adjusted equal to the growth of the other bone. More particularly, the invention related to expandable mechanism proximal femur prosthesis. The expandable mechanism of the present invention is not limited to proximal femur prosthesis, but it can be utilized in (1). Distal femur, (2). Proximal tibia, (3). Distal tibia, (4). Proximal Humorous and (5). Distal Humorous with elbow. This expanding mechanism not only just rectify the timely

shortage of length but also it help to increase and to extend the correct length in the region whenever if needed.
4. OBJECT OF INVENTION:
This expandable mechanism in proximal femur prosthesis like other (1). Distal femur, (2). Proximal tibia, (3). Distal tibia, (4). Proximal Humorous and (5). Distal Humorous with elbow. This expanding mechanism not only just rectify the timely shortage of length but also it help to increase and to extend the correct length in the region whenever if needed.
5. STATEMENT OF INVENTION:
The expandable mechanism in the proximal femur prosthesis protects the affected bone to normal length when it is fixed in the body and it works as a normal bone. The mechanism of proximal femur prosthesis not only gives the extension of length at time to time compare with other side of the body it also gives normal life to the affected patient. If prosthesis fitted with the body others persons cannot identify that the disability or artificial bone fitted with the bone because of the length of the bone increased step by step without any shortage.
6. SUMMARY OF INVENTION:
The expandable mechanism in proximal femur prosthesis comprises as (a). Proximal Femur housing, (b) Worm gear and cup bearing, (c) Worm Shaft and cup bearing and (d) Expanding shaft with stem. This expandable mechanism in proximal femur relates to rectify the shortage and helps to increase the prosthesis length at the time to time whenever needed.
7. DETAIL OF DRAWINGS:
Figure-1. Illustrates 1) Isometric view of normal expanding length assembly. Figure-1. Illustrates 2) Isometric view of maximum expanding length assembly. Figure-2. a. Housing for expandable. Figure-3. b. Worm gear with cup bearing. Figure-3. c. Worm shaft with cup bearing. Figure-4. d. Expandable shaft with stem.

a. The HOUSING OF EXPANDABLE SHAFT of proximal femur in fig.2 have a total
height in - a6 -, at top of the housing have a angle bore of -a9- for fixing femur head, long vertical
bore at - a4, also a having a threaded hole just above the bottom of housing - a5 - and a horizontal
bore in housing at - a2 - having a threaded mouth portion of - a7 - and also have a slot for locking
washer at - a8 -.
b. The WORM GEAR of proximal femur in fig. 3 consist of the worm gear at the middle of
- b8 - with outer diameter of- b9 - and step diameter of- b6 - step length of- b7 - in one end.
The other end of the worm gear having a extension portion length of - blO - with diameter of-
bl 1 - it also a have a hexagonal mouth bore in - b 12 - at the end of the extension portion. Between
to the worm gear and extension portion having a collar of - bl7, The extension portion
accommodate the thrust spacer - bl3 -, nut - bl4 -, lock washer - bl5 - and lock nut - bl6. The
thrust cup bearing having outer diameter of - bl - and step diameter of - b4 - with the step length
of - b3 - and seating area of - b2 - with the housing and inner seating area of- b5 - for the worm
shaft.
c. The WORM SHAFT of proximal femur in fig.3 has a step height of- c9 - in upper end,
step diameter - c8 and upper face - clO. The middle portion of worm shaft having gear meshing
area - cl 1. A long threaded portion at - cl3 - with the outer diameter of - cl2 and also having a
sub assembly of thrust cup bearing with the height of - cl, Housing seating area - c6 - in the
upper portion of bearing, step bore diameter of- c3 -, step height of- c4 -, seating area of - c5 -
and outer diameter of - c2 -.
d. The EXPANDING SHAFT WITH STEM of proximal femur in fig.4 have a long shaft
in - d5-, length of the female threaded portion in - d4- and the inner thread bore of- d2, the outer
diameter of expanding shaft - dl- and - d3- indicates keyway slot and also step collar at the end of
the expanding shaft - d6- and a stem - d7- at the bottom of expanding shaft.

8. DETAILED DESCRIPTION OF INVENTION:
The expandable mechanism in the proximal femur housing in fig.2 having a angle bore of-a9- at the top to accommodate the ball socket for proximal head and adjoin to the angle bore -a9-have a long vertical bore of-a4- to accommodate the worm shaft with the seating area of-a3- to accommodate cup bearing -c2- of worm shaft and just above the bottom of the housing have a threaded portion of -a5- to resist the rotation movement of the expanding shaft and it provides longitudinal travel. The vertical bore of -a4- is to accommodate the outer diameter of expanding shaft and helps to support at the time of longitudinal travel. The housing of horizontal bore -a2-adjoin to the tip of the bore -al- and one end of horizontal bore to accommodate -bl- of the worm shaft cup bearing and middle portion of the horizontal bore to accommodate the -b8- of the worm gear meshing area and open end of the horizontal bore -a7- to accommodate the extension portion of the worm gear with thrust spacer, nut, lock washer and lock nut. This mechanism gives the prosthesis long life without loosening or fixing.
The worm shaft step outer diameter - c8- goes into the bore diameter of- c3- in thrust cup bearing and seated with - clO- and threaded portion of- cl5- in worm shaft assembly goes into the female threaded portion of expanding shaft - d2 - in fig.4.
This sub assembly of worm shaft -c- and expanding shaft -d- goes into the vertical bore of - a4- in fig.2 of the housing. The thrust bearing cup seating area of -c6- is seated with the expanding bore end of the housing - al. Thus the thrust cup bearing and worm shaft upper portion worked as a load bearing the UHMWPE cup bearing work as a lubricant and resist metal to metal friction and free rotation to the worm gear and worm shaft. At the time bottom of the housing a screw entered through the threaded hole at - a5- in fig.2 of housing and seated with the expandable shaft keyway slot - d3 - in fig.4. The entire threaded portion of -cl2- of worm gear shaft goes into the full depth of-b2- of the expandable shaft. The expanding shaft outer diameter -dl- travelled through the vertical bore of -a4- in housing along with the keyway slot upto the end of screw provided in the housing -a5. This mechanism of expanding upon the keyway slot -d3- provided in

expandable shaft with screw fitted in the housing -a5 and threaded portion of worm shaft -d4- and expandable shaft -cl3.
The worm gear step outer diameter of - b6 - in fig. 3 entered into the inner step diameter of - d4 - of thrust bearing cup and seated with the seating area of thrust bearing cup - b5 -This assembly goes through the horizontal bore of housing - a2 - in fig. 2 and worm shaft gear meshing area and seated with - a3 - horizontal bore seating area end. It gives a smooth rotation to the worm gear without any wear and tear at the time of expanding. Then the thrust spacer - bl3 - entered through the mouth of - a7 - and seated with the worm gear collar of- bl7 - and it works as a thrust bearing followed by a nut - bl4- entered into the housing and tightened by a box spanner with worm gear threaded portion. It protects the worm gear and helps to the entire mechanism in rotating movement of the worm gear. This assembly gives a smooth vertical movement without any gap between worm gear and worm shaft of the entire assembly to ensure the fitting permanently and without loosening or over tightening. The lock washer of - bl5 - seated with the groove provided in housing - a8- and lock washer locked by a locknut - bl6-. The lock nut seated adjoin to the lock washer it not allows the lock washer comes out from the position and ensure the locking system of the entire expanding mechanism of the proximal femur prosthesis. In Fig. 1 part.2 illustrates the maximum expanding length of the proximal femur prosthesis
The hexagonal bore in -bl2- of the worm gear is driven by a surgical tool which the entire mechanism of expanding gives a vertical movement. The cup bearing fitted with the worm gear give smooth rotation and acts as a lubricant at the time of load acting between the housing and worm gear. The cup bearing fitted with the worm shaft reduces the load acting between the housing and worm shaft of the proximal femur prosthesis. The stem of the expanding shaft gives into the intramedullary canal of the femur bone and fastened permanently.

1. I claim the expanding mechanism in the proximal femur prosthesis comprising of the housing have a long vertical bore to accommodate the worm shaft and expandable shaft and upper portion of the housing have a angle bore to provide fixing of the proximal femur head adjoin to the top of vertical bore have horizontal bore to accommodate the worm gear assembly with a threaded mouth portion and slot for locking washer. The worm shaft upper step portion fitted with thrust cup bearing assembled with the female threaded portion of the expanding shaft. This sub assembly of worm shaft and expandable shaft seated with the vertical bore of the housing. The worm gear with a step at one end fitted with a thrust cup bearing goes through the horizontal bore of the housing and meshing with the grooves of worm shaft and seated with the horizontal bore in the housing. The thrust spacer fitted with the extension portion of worm gear with nut at the threaded portion of the housing. The lock washer and lock nut is fitted with the housing to keep locking system in permanently. The hexagonal mouth provided in the worm gear helps to actuate the expanding mechanism of the system when it turned by the spanner the worm gear drives the worm shaft gear it gives a longitudinal movement up and down to the expandable shaft to extend the length of the system when it is required at the time of expanding. A screw is fixed in the keyway slot provided in the expanding shaft through the point of -a5- in the vertical bore of the housing allows the vertical movement only to the expandable shaft. The stem of the expandable shaft fastened with the intramedullary canal of the femur bone. At the top of the housing have a angle bore to provide fixing with the femur head. The expandable mechanism in proximal femur prosthesis also utilized for the following prosthesis of (1). Distal femur, (2). Proximal tibia, (3). Distal tibia, (4). Proximal Humorous and (5). Distal Humorous with elbow. 1) The expandable mechanism in proximal femur prosthesis in claim 1 - housing have of long
vertical bore to accommodate the worm shaft with cup bearing and expandable shaft and
horizontal bore to accommodate the worm gear with cup bearing, thrust washer, nut, lock
washer and lock nut.

2) The expandable mechanism in proximal femur prosthesis in claim 1 - has worm gear consists of a thrust bearing cup in one end and gear portion in middle and extension shaft in the other end with a hexagonal hole in the face to provide the turning expanding mechanism.
3) The expandable mechanism in proximal femur prosthesis in claim 1 - worm gear assembly fitted with thrust spacer, between the gear and nut to provide smooth rotation and the protection from wear and tear also resist the metal to metal friction.
4) The expandable mechanism in proximal femur prosthesis in claim 1 - has worm gear assembly the nut protects the mechanism from over tightening and loosening when it utilized.
5) The expandable mechanism in proximal femur prosthesis in claim 1 - has worm gear assembly the lock nut provides gives full protection from loosening or jamming the mechanical system of the worm gear assembly.
6) The expandable mechanism in proximal femur prosthesis in claim 1 - gives full locking system provided by a locking washer and locking nut at the end of the worm gear.
7) The expandable mechanism in proximal femur prosthesis in claim 1 - provides smooth vertical movement by using a surgical hexagonal tool at the mouth of worm gear.
8) The expandable mechanism in proximal femur prosthesis in claim 1 - has a cup bearing fitted with the tip of the worm shaft mate with the gear outer diameter and also seated with the end of the vertical bore and seated with the face end in - al - of the housing. This system worked as a thrust bearing mechanism. The cup bearing made of UHMWPE it resist the wear and tear and give smooth friction free rotation.
9) The expandable mechanism in proximal femur prosthesis in claim 1 - have worm gear and worm shaft give smooth and longitudinal movement through the expandable shaft.
10) The expandable mechanism in proximal femur prosthesis in claim 1 - the worm shaft threaded portion fitted with the expandable shaft threaded female portion gives maximum length as required by the surgeon.

1 l)The expandable mechanism in proximal femur prosthesis in claim 1 - a screw is fitted through threaded portion of the housing it resist the rotating movement and allows the longitudinal travel through the slot provide in the expandable shaft.
12) The expandable mechanism in proximal femur prosthesis in claim 1 - the expandable shaft with stem travel through the vertical bore of the housing and guided by the keyway slot provided in expandable shaft with a screw fitted in the housing.
13) The expandable mechanism in proximal femur prosthesis in claim 1 - the maximum length of expanding mechanism is depends upon the threaded portion of worm shaft, threaded portion of expandable shaft and keyway slot.
14) The expandable mechanism in proximal femur prosthesis in claim 1 - can be utilized for following prosthesis such as (1). Distal femur, (2). Proximal tibia, (3). Distal tibia, (4). Proximal Humorous and (5). Distal Humorous with elbow.