Modular knee finishing block and method of finishing an artificial limb

A modular knee finishing block comprising a rigid molded finishing block having an upper and a lower surface and a posterior surface extending between the upper and lower surface, and a tapered surface extending between the upper and lower surface between opposed edges of the posterior surface, and having a knee bracket casting receiving cavity formed in the finishing block and opening into the lower surface and the posterior surface. The receiving cavity has a receiving surface with a plurality of attachment members opening into the receiving surface and each including a passage between the receiving surface and the upper surface. A pair of posterior flexion clearance grooves extend from the receiving surface to the posterior surface. A finishing plug is shaped to conform to the receiving cavity and have a lip sealingly engaging the bottom surface adjacent the receiving cavity, and to conform to the shape of the grooves. An alignment duplication mandrel and alignment plate is used to hold the knee finishing block in an aligned position to duplicate the knee finishing block's alignment in the finished artificial limb.

FIELD OF THE INVENTION 
The field of the invention pertains to the field of prosthetic devices, 
more particularly knee finishing blocks. 
BACKGROUND AND SUMMARY OF THE INVENTION 
In the past it has been common to supply a wooden knee platform assembly 
kit along with an artificial limb for above-the-knee amputees. Because the 
alignment and overall length of the artificial limb are crucial to proper 
operation, and because each stump socket must be custom made for each 
individual amputee, the prior art provided this wooden knee platform 
assembly kit to attach the knee platform to the lower end of the stump 
socket. Such attachment must be aligned and sized properly for each 
individual patient. Several such wooden knee platform assemblies are shown 
in a brochure of United States Manufacturing Company entitled 
"Endoskeletal Prosthetic Systems" at pages 52-59 attached to the Prior Art 
Statement filed along with the present application. 
The procedure used in the prior art to align and attach the artificial limb 
knee bracket casting, used for attaching the lower leg portion of the limb 
containing the mechanical cadence apparatus to the stump socket, is shown, 
e.g., in a manual of United States Manufacturing Company entitled 
"Hydra-Cadence Guide Book". A copy of that book is also attached to the 
Prior Art Statement referred to above. 
The pertinent portion of such procedure involves first properly aligning 
the lower leg cadence portion of the artificial limb to the stump socket 
on the patient's leg with the patient standing. The above referenced 
manual shows a wooden stump socket; however, it is now also common to form 
the socket of a lamination of suitable material, e.g., organic plastic 
material or hardenable organic polymer foam materials. Steps 11 and 13 at 
page 18 of the above referenced manual show the artificial limb, with a 
lower leg cadance portion simulator, in an alignment jig, with an 
alignment coupling in place. The alignment coupling is a pair of plates, 
one tripod mounted upon the other. Mechanical means are provided to adjust 
the distance between the plates and the angles of the plates to custom-fit 
the lower leg portion of the artificial limb to the stump socket. In the 
case of the wooden stump sockets shown in the above referenced manual, the 
lower end thereof is cut flat to receive one plate of the alignment 
coupling. In the case of currently used laminated or otherwise formed 
stump sockets, a lower end block is provided to receive the one plate of 
the alignment coupling. The upper and lower portions of the artificial 
limb are removed from the jig after certain measurements are recorded with 
the whole unit in the jig. The above referenced manual shows a horizontal 
alignment jig; however it is also now common to use a vertical alignment 
jig, e.g., a Hosmer "Milmo", verticle duplication machine. 
The knee bracket casting is then placed on the knee platform. The knee 
platform is a flat generally rectangular piece of wood having a pair of 
bolts extending through it from a reinforcing plate and protruding from 
the lower side thereof. Also attached to the lower side is a socket plate 
containing receiving sockets for a pair of posterior hex spacers with 
studs, which screw into a respective one of the receiving sockets. 
Integral with the socket plate is a metal reinforcing strap. 
The knee bracket casting, with the attached cadence mechanical apparatus 
for the lower leg portion of the artificial limb, is attached to the knee 
platform by a pair of anterior hex spacers which screw onto the bolts and 
by the pair of posterior hex spacers with studs which screw into the 
sockets. 
The knee platform and attached cadence mechanism is then placed in an 
alignment jig, which has been previously set into proper alignment of the 
lower leg portion of the artificial limb and a stump socket for a 
particular patient, along with the proper length and foot alignment for 
that patient as described above with respect to the use of the alignment 
coupling. The lower leg mechanical portion has also been properly aligned 
to the knee bracket casting. Once on the jig, the knee platform is then 
leveled, if necessary, to a 90.degree. angle to the jig horizontal. 
The stump socket is then brought into contact with the upper side of the 
knee platform and the stump socket is trimmed in length as necessary. 
Thereafter, the outline of the lower end of the stump socket is traced on 
the knee platform. 
The knee platform and stump socket are then removed from the jig and holes 
drilled through the knee platform for reinforcing screws to attach the 
knee platform to the stump socket. The knee platform is then glued to the 
stump socket and the reinforcing screws installed. This procedure of using 
reinforcing screws is only applicable when the stump socket is made of 
wood. Currently it is common to use certain suitable rigid urethane foams 
for the stump socket, in which event no reinforcing screws are used. 
Certain other steps are then carried out to align the foot portion of the 
lower leg portion of the artificial limb, which are not pertinent to the 
present invention. 
A spare temporary knee bracket casting is then attached to the bolts and 
sockets on the lower side of the knee platform and a wooden fairing is put 
in place onto the lower side of the knee platform. The wooden fairing has 
a cut-out conforming generally to the outline of the spare knee bracket 
casting. The wooden fairing is temporarily held in place frictionally, by 
attaching the plastic knee cap to the knee bracket casting. The knee 
platform and the fairing are then cut and sanded to conform to the shape 
of the lower end of the stump socket and, in the case of a wooden stump 
socket casting, a channel is cut for the metal reinforcing strap which is 
then screwed into the channel. In the case of urethane foam stump sockets 
the metal reinforcing strap is attached to the stump socket by embedding 
it in the foam. 
The knee cap and fairing are then removed and grooves are cut using, e.g., 
a rounded file, in the posterior portion of the knee platform to allow for 
clearance of the side frames of the cadence mechanism when the artificial 
limb is flexed. The temporary knee bracket casting must be removed to 
fully cut and shape the grooves. 
The sockets in the knee platform and the extending portions of the bolts in 
the knee platform are then coated with a lubricant, e.g. silicon, and a 
piece of stockinette is pulled over the end of the knee platform and stump 
socket casting making holes for the bolts. The stockinette is painted with 
a polyester resin over the distal end of the knee platform and for several 
inches along the stump socket, avoiding coating the bolts. A piece of PVA 
sheeting is then pulled over the distal end. The PVA sheeting is taped 
down to insure it conforms to the shape of the previously cut grooves. 
The temporary knee bracket casting is then coated with the silicon 
lubricant and the knee bracket casting, wooden fairing and knee cap are 
placed in position and secured by the anterior hex spacers, posterior hex 
spacers with studs and the knee cap screws. Tape is then supplied to 
further hold the fairing in place and the excess stockinette is cut away, 
along with the removal of the tape, once the resin hardens. 
The knee cap, fairing and temporary knee bracket casting are then detached 
and the PVA sheeting is removed. Further lubricant, e.g. silicon grease is 
applied to the temporary knee bracket casting and it is reinstalled on the 
knee platform. Modeling clay is then applied to the knee platform to 
provide a seal between the knee platform and the temporary knee bracket 
casting. The fairing is then placed on the knee platform. The seal 
prevents later-to-be-applied resin from entering between the knee platform 
and the knee bracket casting. A clay seal is then formed on the fairing 
around the circumference of the knee cap, which is then put in place and 
the excess clay trimmed. 
Clay is then used to seal all of the openings in the knee cap plastic 
piece. Finally a stockinette is put in place over the whole assembly of 
the stump socket casting and knee platform and knee cap assembly. A PVA 
bag is pulled over the stockinette and resin poured into the bag to form 
the stockinette into a hardened smooth outer covering for the upper 
portion of the artificial limb. 
The stockinette is trimmed away from the knee cap area, once the resin 
hardens, being careful to trim at about one half-inch overlap onto the 
knee cap and fairing. The knee cap and temporary knee bracket casting are 
removed. The edges of the fairing are then trimmed and all modeling clay 
removed from inside the fairing and from the knee cap. 
It is thus apparent that the above described procedure is very time 
consuming and messy. It contains several steps which if improperly carried 
out could lead to an improper alignment or fit for the artificial limb, 
necessitating repeating the process. It also involves much skilled labor 
and the use of large and expensive cutting and wood finishing machinery in 
the prosthetic laboratory. There is, therefore, a need for a simpler 
method and apparatus for attaching the lower portion of the artificial 
limb to the stump socket while still maintaining the proper alignment and 
sizing. 
The problems enumerated in the foregoing are not intended to be exhaustive, 
but rather are among many which tend to impair the effectiveness of the 
previously known methods and apparatus for aligning, sizing and finishing 
the attachment of the stump socket portion to the lower leg portion of an 
artificial limb for above-the-knee amputees. Other noteworthy problems may 
exist; however, those presented above should be sufficient to demonstrate 
that the prior art method and apparatus for aligning sizing and finishing 
the attachment of the stump socket and lower leg portion of an artificial 
limb for above-the-knee amputees have not been altogether satisfactory. 
The present invention, therefore, relates to a modular knee finishing 
block. More particularly, the present invention relates to a molded rigid 
knee finishing block having an upper surface and a lower surface, and a 
curved tapered surface extending between the upper and lower surfaces and 
the edges of the posterior surface. A knee bracket casting receiving 
cavity is formed in the finishing block and has a receiving surface with a 
plurality of attachment members opening onto the receiving surface and 
each containing a passage between the receiving surface and the upper 
surface. A pair of posterior flexion clearance grooves extend from the 
receiving surface to the posterior surface. A finishing plug conforms to 
the shape of the cavity and grooves and has a domed surface which assists 
in shaping the finished outer surface of the upper leg portion of the 
artificial limb. An alignment duplication mandrel and alignment plate is 
used to hold the knee finishing block in an aligned position to duplicate 
the knee block's alignment in the finished artificial leg. 
Examples of the more important features of the present invention have thus 
been summarized rather broadly in order that the detailed description 
which follows may be better understood, and in order that the contribution 
to the art may be better appreciated. There are, of course, additional 
features of the invention that will be described hereinafter and which 
will form the subject of the appended claims. These other features and 
advantages of the present invention will become more apparent with 
reference to the following detailed description of a preferred embodiment 
thereof in connection with the accompanying drawings wherein like 
reference numerals have been applied to like elements.

DETAILED DESCRIPTION 
Turning now to FIG. 1 the knee platform assembly of the prior art is shown 
to include a knee platform 10 which consists of a flat rectangular piece 
of wood approximately one-half inch thick. The knee platform 10 has a pair 
of stud sockets 12 mounted therein. Each stud socket 12 has a broad flat 
top 13, flush with the top surface of the knee platform 10, and a 
screwdriving slot 15 in the flat top 13. A reinforcing strap 14 is 
integrally formed on a strap anchoring plate 16 on the bottom, i.e., knee 
joint, side of the knee platform 10. The strap reinforcing plate 16 has a 
pair of threaded openings (not shown) through which the stud sockets 12 
pass, into which threads (not shown) on the outer wall of the stud sockets 
12 are threaded. A pair of studs 18 also pass through the knee platform 10 
and are mounted to a stud anchoring plate 20 on the top side of the knee 
platform 10. 
The fairing 22, discussed above, is a somewhat thicker block of wood, i.e., 
of about one and one-half inches thick at its maximum at the anterior side 
21 thereof, with the bottom side thereof defining a uniform thickness for 
a portion of the fairing and then a slight taper, terminating at a 
thickness of about one inch at the posterior end 23 thereof. A knee 
bracket casting cut-out 24 is formed at the center of the posterior end 23 
of the fairing 22. 
The spare knee bracket casting 25, as is also discussed above, is formed of 
an integral piece of metal and is fitted to the knee platform 10, with or 
without the fairing 22 in place, by a pair of anterior hex spacers 26, 
which are threaded onto the studs 18, and a pair of posterior studs 28 
with hex spacers integrally attached. The molded plastic knee cap 30 is 
then placed in position with its integrally formed knee cap screw sleeves 
32 aligned with the respective one of the hex spacers 26 and posterior hex 
spacers with studs 28, and knee cap screws 34 are then extended through 
the sleeves 32 and threaded into internal threads on the anterior hex 
spacers 26 or on the hex spacers on the posterior studs 28, passing 
through corresponding holes 27 in the spare knee bracket casting. 
The elements of the knee platform assembly are shown in FIG. 1 in order to 
assist in understanding the above description of the method and apparatus 
of the prior art. 
Turning now to FIGS. 2-4 the modular knee block apparatus of the present 
invention is shown. A modular knee finishing block 40 is shown to have a 
bottom surface 42 and a top surface 44. A generally flat posterior surface 
46 extends between the top and bottom surfaces 44, 42 at the posterior 
facing side of the knee finishing block 40. A tapered surface 48 also 
extends between the bottom and top surfaces 42, 44, tapering towards the 
bottom surface 42. The tapered surface 48 extends between the opposite 
side edges of the posterior surface 46 and forms three general regions 
consisting of a medial surface 50, a lateral surface 52, and an anterior 
surface 54, assuming the modular knee finishing block 40 of FIGS. 2-4 is 
for an artificial limb to be placed on the left leg of a patient. 
The knee finishing block 40 has a knee bracket casting receiving cavity 58 
which opens into the bottom surface 42 and the posterior surface 46, and 
contains four attachment members 56 which terminate flush against a knee 
bracket casting receiving surface 64. The knee bracket casting receiving 
surface 64 is a generally flat surface at the deepest penetration of the 
knee bracket casting receiving cavity 58 into the knee finishing block 40, 
i.e., at the terminal end of a cavity wall 62, defining the cavity 58. 
A pair of posterior flexion clearance grooves 60 slant upwardly from the 
knee bracket casting receiving surface and open into the posterior surface 
46. These allow for clearance of the side frames (not shown) of the 
cadence mechanism (not shown) contained in the lower portion of the 
artificial limb (not shown), when the cadence mechanism is attached by 
attaching its knee bracket casting to the attaching members 56, and when 
the artificial limb is in the flexed position. For some currently 
available cadence units, there is no need for the flexion clearance 
grooves 60 and they can be, thus, optionally formed in the molded knee 
finishing block 40. 
FIG. 3 shows, in the top view depicted therein, that the cavity wall 62 
slants inwardly slightly over most of the circumference of the cavity 58 
defined by the cavity wall 62, except for the opposed portions of the 
cavity wall 62 adjacent the clearance grooves 60. The receiving surface 64 
thus has a slightly smaller circumference in the region where the side 
wall 62 slants inwardly. 
FIG. 4 shows in cross-section the components which are imbedded in the knee 
finishing block 40. Each of the attachment members 56 has a stud socket 70 
having internal and external threads, as shown in more detail in FIGS. 5 
and 6. FIGS. 5 and 6 show, respectively, a bottom view and a side view of 
the component parts of the knee finishing block 40 imbedded within the 
knee finishing block 40. An outline of the knee bracket casting receiving 
surface 64 is shown in FIG. 5 to assist in visualizing the location of the 
components shown. The two posterior-most attachment members 56 as shown in 
FIG. 4 are threaded through one of a pair of holes in a reinforcing strap 
anchor plate or support plate 76, to which is integrally attached a 
reinforcing strap 74 which lies just inside the finishing block 40 from 
the receiving surface 64, with the stud sockets 70 extending through the 
anchor plate 76 to lie flush with the receiving surface 64. The 
posterior-most attachment members 56 are also each threaded through one of 
a pair of holes in a reinforcing bar 78. The attachment member 56 stud 
sockets 70 each have a head 84 which has an opening therein (not shown) to 
provide, in conjunction with a passage 92, formed in the knee finishing 
block 40, an opening between the top surface 44 and the receiving surface 
64. 
The anterior-most pair of attachment members 56 are each comprised of an 
identical stud socket 70 having a head 84 with an opening to a passage 92 
formed in the finishing block 40. The anterior-most pair of attachment 
members 56 could also be threaded through a reinforcing bar, similar to 
reinforcing bar 78. However, they are shown to be optionally provided with 
additional reinforcement through the threading thereon of a nut 88, as 
explained in more detail in regard to FIGS. 5 and 6. It will also be 
understood that reinforcing bar 78 could be replaced by reinforcement 
through the use of a nut 88, or that nuts 88 could be used on the 
posterior-most attachment members 56 and a reinforcing bar 78 used on the 
anterior-most attachment members 56. 
The posterior-most attachment member stud sockets 70 are shown to have 
interior threads. In FIG. 6 the posterior-most stud sockets 56 are shown 
to pass through the reinforcing strap anchor plate 76 a slight distance 
equal to the distance which the anchor plate 76 is displaced from the 
receiving surface 64. The posterior-most stud sockets 70 also are threaded 
on external threads 90 through a reinforcing bar 78 which has a right wing 
80 and a left wing 82, as viewed in FIG. 5. The right and left wings 80, 
82 are bent away from the anchor plate 76 to accommodate the locations of 
the clearance grooves 60 in the finishing block 40. FIG. 6 is partially 
cut away in the region of the right wing 80 to show the head 84 of the 
socket stud 70, normally hidden in the side view of FIG. 6. 
The view of the anterior-most attachment members 56 in FIGS. 5 and 6 more 
fully illustrates the construction of the stud sockets 70, of both the 
anterior-most and posterior-most attachment members 56. The stud sockets 
70 of the anterior-most attachment members 56, as well as the 
posterior-most attachment members 56, have internal threads 72 extending 
throughout the length thereof. A large flat head 84, having a tapered 
underside, is formed at one end of the stud sockets 70. The stud sockets 
were simply chosen for the present invention from available off-the-shelf 
items, and thus are identical in construction to the stud sockets which 
come with the knee platform of the prior art shown in FIG. 1. Thus, they 
have a screw driving slot 86 therein. The anterior most stud sockets 70 
are shown to have threaded on the external threads 90 thereof a nut 88. 
The knee finishing block 40 of the present invention is composed of a 
suitable strong rigid thermo-setting plastic material, e.g., a high 
density polyurethane. A mold is constructed in the shape discussed above 
and the components shown in FIGS. 5 and 6 are placed in the mold, which 
has an open top where the top surface 44 of the knee finishing block 40 
will ultimately be formed. It will be understood that the particular form 
of the stud sockets 70 is not crucial to the present invention so long as 
they will be anchored firmly within the knee finishing block 40 when the 
thermo-setting material sets. Thus in the form shown in FIGS. 5 and 6, the 
broad head 84 on each stud socket 70, and the external threads 90 serve to 
anchor the stud sockets 70 within the hardened material of the knee 
finishing block 40. The reinforcing bar 78 and nuts 88 are added for 
further firmly securing the stud sockets 70 within the hardened material, 
but are optional. As the material hardens around the threads 90 and head 
84 of each stud socket 70, sufficient locking of the stud sockets within 
the hardened material occurs, but for added reinforcement the hardening of 
the material around the reinforcing bar 78 and/or the nuts 88 is useful. 
In order to form the passages 92, a stud (not shown) can be placed in each 
of the stud sockets 70 positioned in the mold prior to adding the 
thermo-setting material. Each stud is threaded into the opening in the 
head 84 end of a respective one of the stud sockets 70 and left in that 
position until the thermo-setting material has firmed up enough to leave a 
passage 92 when the stud is removed, but not sufficiently to prevent 
removal of the stud. Removal of the studs at such a time, therefore, 
leaves the desired passages 92. 
FIGS. 7-13 show the manner in which the present invention is utilized. 
Referring to FIG. 7, a stump socket 101, formed from a mold of the 
patient's upper leg stump (as known to the art) is temporarily attached to 
an alignment coupling 114 (also as known to the art, for example, a 
Staros-Gardner coupling) which permits the stump socket 101 to tilt or 
slide in all planes. Normally attachment is accomplished via a wood block 
116 screwed to the top surface of the coupling 114 and adhered to the 
socket 101 with resin or organic polymer foam material 118. 
Referring to FIG. 8, once the stump socket 101 is attached to the alignment 
coupling 114, a knee mechanism 126 is attached to the socket-coupling 
unit. The knee mechanism 126 includes a knee bracket casting 25, such as 
shown in FIG. 1 and is attached to the socket 101 with bolts 124 that pass 
through holes in the knee bracket casting 25. The casting holes align 
precisely with threaded holes through the alignment coupling 114 and, 
later, with the knee block holes 56 (FIG. 3). 
There is thus provided an entire temporary leg consisting of the stump 
socket 101, wooden block 116 and resin or foam adhesive 118 therefor, 
alignment coupling 114 and knee mechanism 126 including the knee bracket 
casting 25. The patient is then walked on this temporary unit. Alignment 
changes are made as needed using the alignment coupling 118 and the length 
of the entire unit is adjusted by substituting a thicker or thinner block 
116 and/or adhesive 118 as appropriate. 
Referring to FIG. 9, when alignment is completed the knee mechanism 126 is 
removed and a mandrel 96 is attached to the alignment coupling 114. The 
mandrel 96 includes an upper alignment plate 100 which duplicates in shape 
the flat portion of the knee bracket casting 25 with correspondingly 
located stud holes through which bolts 125 are used to secure the mandrel 
96 to the alignment coupling 114. The upper alignment plate 100 is shown 
to comprise a flat plate. It will be understood that it could also be, 
e.g., a spare knee bracket casting 25 welded, or otherwise attached, to 
the mandrel 96 to thereby duplicate the flat portion of the knee bracket 
casting 25 at the upper end of the mandrel 96. The mandrel 96 is shown to 
be an elongated pipe or bar, and has means at its lower end for attaching 
the mandrel 96 to an alignment jig 95 as known to the art, e.g., a "Milmo" 
vertical duplicating apparatus. 
The resulting unit is placed in a Milmo apparatus 95 (shown schematically 
and not fully) and the mandrel 96 is secured to a lower alignment plate 98 
of the Milmo apparatus 95 by means of a socket screw and allen wrench (not 
shown) thereby securing the stump socket 101-coupling 114-mandrel 96 
system to the lower end of the Milmo apparatus 95. A pipe 120 is then 
inserted into a sleeve member 121 carried on the upper arm 122 of the 
Milmo apparatus so that a substantial length of the pipe 120 extends into 
the cavity of the stump socket 101. The socket 101 is filled with plaster 
130 which, when set, secures the upper Milmo arm 122. 
Alignment of the stump socket 101 is now secure. As long as the mandrel 96 
and upper alignment plate 100 are not disturbed and as long as the stump 
socket 101 secured in the plaster 130 is not disturbed, the 
interconnecting components (i.e. the alignment coupling 114, the wooden 
block 116 and the resin or foam adhesive 118) can be removed from the 
system and replaced with the knee block 40 of the present invention to 
provide a light weight and cosmetic finish. Referring to FIG. 10, the 
resin or foam adhesive and/or wooden block 116 can be cut away to leave 
the bottom of the stump socket spaced from and securely suspended over the 
upper alignment plate 100 of the mandrel 96. 
Referring to FIG. 11 as a next step, the finishing block 40 is placed on 
the upper alignment plate 100 and threaded screws are passed through the 
upper alignment plate 100, the stud sockets 70 and passages 92 (FIG. 4) in 
the finishing block 40. The upper alignment plate 100 and a portion of the 
mandrel 96 extend into the receiving cavity 58. 
Referring to FIG. 12, a piece of 1/8" thick polyethylene sheeting 126 
(shown cut-away) is wrapped around the knee finishing block 40, the 
vertical dimension of the sheeting 126 extending to encircle a substantial 
portion of the stump socket 101. Polyurethane foam 128 is poured in liquid 
form into the space between the socket 101 and sheeting 126 and allowed to 
foam up and become rigid. To facilitate securement of the polyurethane 
foam 128 to the knee block 40, prior to pouring the foam liquid, a layer 
124 of epoxy adhesive is applied to the upper surface of the knee block. 
The foamed unit is removed from the Milmo apparatus 95 and is cosmetically 
shaped to resemble the patient's leg. The mandrel 96 and upper alignment 
plate 100 are then removed. A finishing plug 106, shown in FIG. 13 is then 
inserted into the receiving cavity 58. The finishing plug 106 has a plug 
portion 108 which conform to the shape of the receiving cavity wall 62, 
receiving surface 64 and grooves 60, and has a lip 109 which extends to 
the rim of the bottom surface 42 along the lower edge of the lateral, 
anterior and medial sides 50, 54, 52 of the tapered side 48 of the 
finishing block 40. This sealingly engages the bottom surface 42. The 
finishing plug 106 also has posterior wall 110, which when the plug 106 is 
in place, conforms to the plane of the anterior wall 46. A pair of groove 
plug members 112 protrude from the edge of the posterior wall 110 and the 
flat surface of the plug portion 108. The finishing plug 106 is composed 
of a suitable material, e.g., an elastomeric material to ensure a snug fit 
within the receiving cavity 58. 
A stockinette is then drawn over the finishing plug 106, finishing block 40 
and stump socket 101 from the finishing plug 106 and a PVA sleeve is drawn 
over the stockinette. The stockinette is then hardened by impregnating it 
with a hardenable resin poured into the PVA sleeve from the stump socket 
end. The hardened stockinette is trimmed sufficiently to remove the 
finishing plug 106 and the stump socket and attached finishing block 40 
are now ready for attaching the knee bracket casting for the cadence 
mechanism of the artificial limb by threaded screws inserted into the stud 
sockets 70 of the finishing block 40 as discussed in relation to FIG. 1. 
The rounded domed portion 113 of the finishing plug assists in shaping the 
hardening sockinette and the proper contouring of the lower portion of the 
stump socket 101 outer shell. The stockinette is hardened to the shape of 
the knee-cap by conforming to the domed surface 113 of the finishing plug 
106 leaving a small lip to enclose the knee cap 30 (FIG. 1). 
SUMMARY OF THE ADVANTAGES AND SCOPE OF THE INVENTION 
It will be understood that in the modular knee finishing block and method 
of the present invention certain significant advantages are obtained. A 
significant reduction in the time and skilled nature of the labor 
necessary to finish an artificial limb for above-the-knee amputees is 
achieved. The modular knee block can be pre-molded in varying sizes and 
supplied along with or separate from the lower leg cadence portions of the 
artificial limbs. Alternatively, molds can be supplied and prosthetic 
technicians can fabricate, simply and easily, the knee block of the 
required size for a given patient, using the mold and the associated 
hardware components and a thermo-setting material, e.g., high density 
polyurethane. The mandrel and attached upper alignment plate provide a 
means for aligning the finishing block to the stump socket. 
The foregoing description of the present invention has been directed to a 
particular preferred embodiment in accordance with the requirements of the 
present statutes and for purposes of explanation and illustration. It will 
be apparent to those of ordinary skill in the art, however, that many 
modifications and changes in both the apparatus and method of the present 
invention may be made without departing from the scope and spirit of the 
invention. For example, the particular rigid material used for the modular 
knee block is disclosed by way of example and other hardenable liquid 
materials which can be hardened or cured in a mold may also be used. 
It will further be apparent that the invention may also be utilized with 
suitable modifications within the state of the art. Some examples of these 
include the specific structure of the attachment means disclosed as the 
stud sockets. The stud sockets, as discussed above, were selected from 
existing off-the-shelf items. They could be replaced by other attachment 
means providing a means to connect the finishing block to the simulation 
of the lower leg cadence portion of the artificial limb on an alignment 
jig and for attaching the finishing block to the socket stump. Their shape 
is useful in insuring that they are adequately anchored in an imbedded 
state in the finishing block material, but other shapes could also easily 
be selected. The anchoring reinforcement bar and nut serve a similar 
function of insuring adequate anchoring, but are optional or may be 
modified in shape, so long as the attachment means components are firmly 
imbedded within the finishing block. In addition, the present invention 
has been described in relation to an artificial leg for a human amputee. 
It will be understood, however, that the invention could also be used for 
artificial arms and could also be used in veterinary applications. 
These and other modifications of the invention will be apparent to those of 
ordinary skill in the art. It is applicant's intention in the following 
claims to cover these and other such equivalent modifications and 
variations as fall within the true spirit of the invention.