In this presentation, i have covered all the basics about levels of amputation. I have mentioned the different levels of amputation and their prosthetic management. Beneficial for those who are in the field of P & O.
8. PARTIAL FOOT AMPUTATIONS
AMPUTATION OF THE TOES
• The functional requirement for this type of amputation is largely
cosmetic; however, if the hallux is absent, some consideration should
be given to providing resistance to hyperextension of the first
metatarsophalangeal joint area both to reduce the effect of the loss of
the final element of push-off and to prevent uncomfortable shoe
deformation. In addition, it is desirable to resist deviation of the
remaining toes toward the amputation site.
• Patients may elect simply to use soft foam or cloth to fill voids left in
the shoe. A preferable solution consists of a simple insole to which toe
fillers on spacers formed from orthopedic felt or foam are bonded
(Muilenburg Prosthetics)
• An alternative approach is the use of custom silicone rubber toes
attached to the residuum with medical ad-hesives and held in place
with a sheer nylon stocking; however, this technique is available at
only a few specialized centers (Life-Like Laboratory)
10. RAY AMPUTATIONS
The biomechanical consequences of ray amputations will be largely dependent on the position and extent of the
forefoot segments removed. In the case of diabetic patients, the resulting reduction in the area of the plantar
surface available to transfer the forces encountered during physical activity may be significant. In those instances
where the first or the fifth rays have been removed (with or without the intermediate rays), this effect will be
aggravated by mediolateral instability and may result in more serious pressure problems, particularly during
push-off.
Ray amputations will also reduce the effectiveness of the pronatory/supinatory movements of the forefoot by
impairing both its interaction with the subtalar joint and its role in responding to irregularities and slopes in the
walking surface. Custom insoles fabricated from pressure-sensitive materials may be used to distribute pressure
evenly over the remainder of the foot. These insoles have a limited life expectancy since they are designed to
gradually deform, thereby protecting the foot from excess pressures. Laminated foam insoles may be used to
increase longevity. Generally a softer, more conforming foam is used against the skin, while a more durable,
stiffer foam that will retain its shape longer is used for the base.
One of the principal problems encountered by the patient with a ray amputation is shoe fit. In more extensive
amputations a foam insert may be used that will position the foot correctly in the shoe and avoid the necessity of
purchasing split sizes of shoes (Life-Like Laboratory)
12. ABOVE ANKLE DESIGNS
Early prosthetic designs took a form similar to an ankle disarticulation (Syme) prosthesis; however, as
has previously been mentioned, these have been found to be bulky and heavy.
Alternative ankle-foot orthotic designs manufactured from thermoplastic materials are both lighter and
more cosmetic; however, these are probably only indicated for those patients where it is necessary to
transfer the weight-bearing forces above the ankle to unload fragile skin at the amputation site or to
compensate for weakened ankle musculature .
All above-ankle systems will inevitable restrict subtalar joint motion, thereby eliminating the normal
mechanism for absorbing the longitudinal rotations of the limb. If slippage between the foot and the
ground is to be avoided, the patient must adopt a modified pattern of hip motion.
Patients wearing above-ankle devices will have the further disadvantage of a reduced range of ankle
motion. Since the extent of the residuum precludes the use of a normal prosthetic ankle mechanism,
these patients will be required to adopt compensatory hip and knee joint movements to cope with this
restriction. This problem may be best addressed by the use of a rocker sole and cushion heel adaptation
to the amputee's shoe.
13.
14. BELOW ANKLE DESIGNS
There appear to be four basic types of construction currently in use:
Rigid
Semirigid
Semiflexible
Flexible
All of these systems are laminated or thermoformed about a positive model of the remaining foot. These
models are carefully modified to decrease pressure where required and increase pressure where tolerated.
15. Rigid and semirigid systems incorporate a foam socket liner that acts as an interface between the walls of the
socket and the surface of the skin. These liners may be of varying thickness and stiffness, depending on skin
tolerance. They are also prone to deterioration and will require replacement in time due to decreasing thickness
and softness of the material. The profile of the foot is restored by a soft or rigid buildup added to the socket.
Rigid and semirigid partial-foot prostheses will generally require cushion heel and rocker sole modifications to
the patient's shoes. The use of rigid and semirigid prostheses is today less common due to the availability of
improved semiflexible and flexible designs.
Semiflexible designs utilize a combination of materials generally having urethane elastomer or a silicone base.
These systems are fabricated over an exact model of the patients remaining foot. Care is taken to ensure a
tolerable distribution of pressure. Reliefs are made for bone prominences, callosities, or sensitive areas.
Material may be removed proximal to the calcaneus to improve the suspension of the prosthesis. A toe filler is
attached to the socket either during the foaming processing or by gluing in place later.
These fillers may simply fill the shoe shape or be carved to simulate the contours of an actual foot and toes.
Color is added during the foaming process or may be painted on to match skin tones at the time of fitting.
Modification of the socket to relieve excessive pressure is generally achieved by modification to the outside
surface of the shell, thereby maintaining the smooth integrity of the socket inner surface.
16. BELOW ANKLE DESIGNS
Slipper-Type Elastomer Prosthesis
The slipper-type elastomer prosthesis (STEP) manufacturing processing is
somewhat complex. Permanent tooling is developed for each individual
amputee and consists of a permanent polyester resin positive model and a
negative mold of the finished artificial foot. The device is fabricated by using
semi-flexible urethane elastomers.
17. THE COLLINS ORTHOPAEDIC SERVICE
PARTIAL-FOOT PROSTHESIS
The socket for this prosthesis is fabricated over a modified positive plaster
model of the stump. Silicone is laminated into a cloth material and reinforced
with woven glass if needed for increased durability. A spring steel is attached
to the plantar surface of the socket and extends to within 1 in. of the toe
(distal end of the finished prosthesis). The contours of the foot are filled out
by using prosthetic foam that is foamed in place by using a plaster toe mold.
18. THE IMLER PARTIAL-FOOT ORTHOSIS-CHICAGO
BOOT
The socket for this prosthesis is vacuum formed over a modified plaster
model in the manner of a University of California Berkeley shoe insert.
The resulting copolymer socket is inserted into a ure-thane elastomer
(Lynadure, Medical Center Prostheses, Houston) cosmetic boot and is
removable for adjustments. The finished prosthesis extends just above
the ankle and is retained by lace-up closures anteriorly.
19. THE SYME ANKLE DISARTICULATION: PROSTHETIC
MANAGEMENT
Disarticulation at the ankle has challenged the prosthe-tist since the procedure was first introduced by Syme in 1842. Surgical modifications have been
introduced to make the stump neater and less bulky, allow more room for the ankle joint, and produce a more cosmetic prosthesis.
A satisfactory end-bearing Syme limb demands a prosthesis with the following characteristics:
Transmission of body loads
Light enough to wear comfortably
Ability to supply the equivalent of foot and ankle function
Lengthening of the limb to adjust for loss of the talus and os calcis
Distribution of the high forces developed in the ankle area
Provision of rotary stability about the long axis
Provision of shock absorption
Suspension during swing phase
Readily donned without requiring multiple non-cosmetic, difficult fasteners
Adjustability to relieve pressure along a sensitive scar line
Cosmesis
Despite the advantages provided by the long lever arm of the essentially intact tibia and fibula and the virtually full end-bearing capabilities of the heel
pad, multiple problems still exist in the design of the "ideal" prosthesis. Reports in the literature of "new prosthetic approaches" attest to the fact that
the final perfect prosthesis has not yet been designed
20.
21. TRANSTIBIAL AMPUTATION
THE PATELLAR TENDON-BEARING SOCKET
The patellar tendon-bearing (PTB) socket consists of a laminated or molded plastic socket. To make a PTB socket, an
impression taken of the patient's residual limb is modified to achieve an intimate, total-contact fit over the entire surface of
the residual limb. It can be suspended in multiple ways, which are discussed later.
The anterior wall of the socket usually extends proxi-mally to encapsulate the distal third of the patella. Just below the
patella located at the middle of the patellar ligament is an inward contour or "bar" that utilizes the patellar ligament of the
residual limb as a major weight-bearing surface. The term patellar tendon bearing can be misleading, however, because the
patellar ligament is not the only major weight-bearing surface utilized by the PTB socket.
The medial and lateral socket walls extend proximally to about the level of the adductor tubercle of the femur. Together
they control rotation, contain soft tissue, and may provide some mediolateral knee stability. The medial wall is modified
with a slight undercut in the area of the pes anserinus on the medial flare of the tibia, thus utilizing another major pressure-
tolerant surface. The lateral wall provides a relief for the head of the fibula and supports the fibular shaft. This wall also acts
as a counterpressure to the medial wall.
The posterior wall is usually designed to apply an anteriorly directed force to maintain the patellar ligament on the bar. The
posterior wall is flared proximally to allow comfortable knee flexion and to prevent excessive pressure on the hamstring
tendons.
The distal portion of the PTB socket may incorporate a soft pad that in theory prevents distal edema by aiding venous and
lymphatic return from the distal part of the residual limb. A soft socket liner may be used for added protection or comfort.
The PTB total-contact socket is appropriate for virtually all transtibial (below-knee) amputations, except in some
postoperative prostheses or when pathologic conditions require an alternative socket.
23. THE PTB HARD SOCKET
The hard socket is rigid plastic and therefore has specific advantages and disadvantages when compared with a socket
with a soft liner or distal pad. This style of socket is primarily indicated for a residual limb with good soft-tissue coverage
and no sharp bony prominences. It is not recommended for residual limbs with thin skin coverage, scarring, skin grafts, or
a predisposition to breakdown.
Advantages:
Perspiration does not corrode the socket.
Less bulky at the knee than with an insert.
Easy to keep clean.
Contours within the socket do not compress or pack down with use.
Reliefs or modifications can be located with exactness.
Disadvantages:
Requires extra skill in casting and modification.
Difficult to fit bony or sensitive residual limbs.
Not as easily modified as a socket with a liner.
25. PTB SUPRACONDYLAR SUPRAPATELLAR
SUSPENSION
The PTB supracondylar, suprapatellar (PTB-SCSP) socket was designed originally as an alternative suspension and
as a means of providing increased mediolateral and anteroposterior stability of the residual limb. This socket
differs from the standard PTB socket in that the medial, lateral, and anterior walls extend higher and fully
encompass the femoral condyles and the patella. The posterior wall is unchanged.
During casting and modification, the proximal mediolateral dimension just superior to the femoral condyles is
reduced to provide purchase over the femoral condyles, particularly the medial condyle. The area just proximal
to the patella may also be contoured inward to create a "quadriceps bar," which provides added suspension
over the patella and resists recurvatum.
This type of suspension is particularly recommended for patients with short residual limbs since it encompasses
more surface area to share weight bearing and resist torsional forces. Patients with mild mediolateral knee
instability or those who cannot tolerate a supracondylar cuff can also benefit from PTB-SCSP suspension. This
socket style generally cannot provide adequate purchase over the femoral condyles for obese or very muscular
patients. Patients with moderate to severe ligamentous laxity usually require the added stability of metal joints
and a thigh corset rather than supracondylar suspension alone.
26. Advantages of PTB-SC-SP:
Suspension is an inherent part of the socket.
Is less restrictive to circulation than a cuff or thigh corset.
Aids in knee stability, rotational control, and pressure distribution.
Reduces pistoning.
Disadvantages of PTB-SC-SP:
Modifications over the patella and femoral condyles must be precisely
located.
Enclosure of the patella can inhibit comfortable kneeling.
May be less cosmetic and more destructive to clothing because higher
trim lines protrude when the knee is flexed.
27. PTB SUPRACONDYLAR SUSPENSION
The major difference between this and the PTB-SCSP socket is that the patella is not enclosed. The medial and lateral brims
purchase over the femoral condyles, but anteriorly they dip downward to form a more traditional trim line near the distal
end of the patella. The quadriceps bar and its knee extension control are thus eliminated.
This suspension may be indicated when a patient wishes to do a lot of kneeling or cannot tolerate the quadriceps bar or
encapsulation of the patella. The patient must have a stable cruciate ligament with no need for an extension stop at the
knee.
It is contraindicated, as is the PTB-SCSP socket, for patients with moderate to severe ligamentous laxity who require the
added stability of metal joints and a thigh corset.
Advantages (over the PTB-SCSP socket)
May make kneeling easier.
May be more cosmetic.
Disadvantages (as compared with the PTB-SCSP socket)
Does not provide a knee extension stop.
May provide less effective suspension than a PTB-SCSP since there is no suprapatellar purchase and because the absence
of patellar encapsulation makes the medial and lateral walls more flexible.
Less mediolateral stability than the PTB-SCSP.
29. KNEE DISARTICULATION
Also known as through knee amputation ( TKA )
ADVANTAGES :
Less traumatic
More leverage
Self suspension
Muscles retain their strength.
DISADVANTAGES :
Amputees may not like the look of bulbous stump.
Unequal length of thigh during sitting.
30. OHC DESIGN
OHC stands for Orthopaedic Hospital Copenhagen
Prsented by Liquist
It has medial opening with a cover to allow the passage of
wide condyles of femur.
Window is provided and this window is on the medial side.
The plate is used to close the window.
A polycentric knee joint is provided directly below the distal
socket.
31. BOTTA TECHNOLOGY
Botta was the first to subdivide the socket for KD
prosthesis into a soft liner and hard socket that is known as
the container socket.
The soft liner tightly contained the stump.
Applying additional material until the outer surface is
almost cylindrical compensating for the undercuts (
concavity ) at the outer surface of the liner.
Then hard container socket is laminated over the inner
liner.
The polycentric knee joint is attached at the distal end.
When donning the prosthesis, the amputee donned the
flexible inner liner first and then carefully, pushes the liner
covered over the stump into outer container socket.
This approach was accepted as BOTTA TECHNOLOGY and is
accepted as standard approach to KD prosthesis.
32. TRANSFEMORAL AMPUTATION
QUADRILATERAL SOCKET
The quadrilateral socket was developed in the late 1950s and is named for the four walls that each have a
specific function.
Distally the socket is contoured to provide total contact for the residual limb.
The POSTERIOR WALL provides major weight bearing area, the ischial tuberosity and some gluteal muscle rest
on top of the wall that is thicker medially than laterally. Internally the wall is contoured for the hamstring
muscles, whereas externally it is flat to prevent rolling in sitting. The height of the posterior wall is
determined by the position of ischial tuberosity.
The ANTERIOR WALL rises about 5 cm ( 2.5 inches ) above the height of the POSTERIOR WALL, and medially,
provides stabilizing pressure to help to keep the ischial tuberosity securely rest on the seat by molding over
femoral triangle. The anterior wall is convex laterally to allow space for the bulk of the rectus femoris muscle.
34. The LATERAL WALL is as high as the anterior wall and inclines
medially to set the residual limb in about 10 DEGREES OF
ADDUCTION, thereby aiding pelvic control in stance. A relief channel
is built in the corner of the medial and anterior walls for the
adductor longus tendon.
The MEDIAL WALL is designed to provide even pressure on the
adductor muscles and to contain all the medial tissues to prevent any
adductor roll.
The QUADRILATERAL SOCKET provides minimal mediolateral and
little lateral rotational stability.
It is not often prescribed today as the first socket, however
individuals who have worn a quadrilateral socket for many years may
be loath to try a different design
35. ISCHIAL CONTAINMENT SOCKET
The term "ischial containment" is rather self-descriptive. It describes several
similar concepts in socket design in which the ischium (and in some cases the
ischial ramus) are enclosed inside the socket.
Pritham has described objectives that would ideally be achieved in the ischial
containment socket:
Maintenance of normal femoral adduction and narrow-based gait during
ambulation.
Enclosure of the ischial tuberosity and ramus, to varying extents, in the
socket medially and posteriorly so that forces involved in maintenance of
mediolateral stability are borne by the bones of the pelvis medially and not
just by the soft tissues distal to the pelvis, that is to say, creation of a "bony
lock."
Maximal effort to distribute forces along the shaft of the femur.
A decreased emphasis on a narrow AP diameter between the adductor
longus-Scarpa's triangle and ischium for the maintenance of ischial-gluteal
weight bearing.
Total contact.
Utilization of suction socket suspension whenever possible.
36. FLEXIBLE TRANSFEMORAL SOCKETS
Flexible walls
Improved proprioception
Conventional fitting techniques
Minor volume changes readily accommodated
Temperature reduction
Enhanced suspension
Pritham proposes the following indications for use of a flexible socket:
Mature residual limb (frequent socket changes not anticipated)
Medium to long residual limb (where a significant portion of the wall will be
left exposed and flexible)
Suspension not a factor
37. HIP DISARTICULATION &
TRANSPELVIC AMPUTATION
The most important part of any prosthesis is the socket, which provides the man-machine interface. During
the initial assessment of the amputee, examination of postoperative radiographs and careful palpation of
the pelvis are recommended. Some amputees present as "hip disarticulation" when they have a short
femoral segment remaining or as "transpelvic" when part of the ilium, sacrum, or ischium remains.
Unanticipated bony remnants can become a puzzling source of discomfort. On the other hand, they may
sometimes be utilized to assist suspension or rotary control or to provide partial weight-bearing surfaces.
Due to the success of ischial containment transfemoral sockets, the importance of precise contours at the
ischium and ascending ramus is now more widely recognized. The same principles can readily be applied to
hip disarticulation sockets to increase both comfort and control.
38. EVOLUTION OF HIP DISARTICULATION
PROSTHESIS
TILTING TABLE PROSTHESIS ( 1940 )
U.S. NAVY HYDRAULIC PROSTHESIS ( 1945 )
CANADIAN HIP DISARTICULATION PROSTHESIS ( 1954 )
SAUCER-TYPE PROSTHESIS ( 1957 )
UCLA ANATOMICAL H.D. PROSTHESIS ( 1980 )
39. EVOLUTION OF HIP
DISARTICULATION PROSTHESIS
DYCOR’s ROLLER TRACK PROSTHETIC HIP ( 1991 )
ORTHO-SYSTEM BUTTERFLY SOCKET ( 1997 )
SILICONE FRAME SOCKET HIP JOINT ( 2000 )
ADVANCES FLEX HIP ( 2001 )
GLENROSE SEMI-FLEXIBLE SOCKET ( 2005 )
40. EVOLUTION OF HIP
DISARTICULATION PROSTHESIS
BIKINI HIP SOCKET TECHNOLOGY
( 2013)
RE-DEFINING HIP DISARTICULATION
WITH THE BIKINI SOCKET ( 2016 )
41.
42. TRANSLUMBAR AMPUTATION
( HEMICORPORECTOMY )
The socket design for the translumbar amputee must precisely identify weight-bearing and relief areas by using
multiple transparent test socket procedures. The major weight-bearing area is the thorax assisted by
containment of the abdominal tissues. Several areas need pressure relief, including the inferior borders of the
scapulae, any prominent spinous processes, the axillae, and the brachial plexus complex. It is desirable to use a
proximally adjustable socket to accommodate weight loss or gain and to allow the amputee to partially
redistribute the weight-bearing forces to increase comfort. The socket design must also accommodate the
ostomy stomas and allow free access to these sites for self-care. The most common design utilizes "mail slots"
to allow the collection bags to remain outside the socket, free of the pressures induced by weight bearing. Any
openings in the socket must be carefully limited, or the abdominal skin will protrude. In some cases, it is
necessary to fashion a latex strap (fastened with Velcro) to cover the "mail slots" and provide gentle pressure
to reduce the soft-tissue herniation. With flat drainage bags, it may be possible to omit the colostomy opening,
provided that the amputee can defecate daily when not wearing the prosthesis.
43. Simons et al. have summarized the goals of socket design for the translumbar
amputee as follows:
Independent transfer in and out of the socket .
Sufficient stability to permit free use of the upper limbs and wheelchair
mobility
Minimum socket tolerance of two 4-hour periods daily
Sufficient weight-bearing pressure distribution to prevent skin necrosis
Allowance for adequate respiratory exchange
No abdominal pain or nausea from pressure within the socket
Prevention of eversion of the colostomy and ileal bladder drainage bags
Easy access to drainage bags for self-care
Pressure relief over the sternum and distal portion of the spine, even when
leaning forward or back in the socket
Acceptable cosmesis
Ease in cleansing socket areas in contact with the body
44. AMBULATORY PROSTHESES
Goals for dynamic alignment include stability of knees and hips,
gentle heel strike, and smooth rollover during stance phase. The gait
pattern may be swing-through using forearm crutches or swing-to
using a walker. As is the case with paraplegia, it is the upper portion of
the body that provides the propulsive force for such ambulation.
Success with a reciprocating gait by swiveling the torso has also been
reported for both bilateral hip disarticulation and for translumbar
amputation, provided that transverse rotation units are incorporated
into the prosthesis.
Due to the small number of cases reported, it is not possible to
recommend particular components. Each clinic team must therefore
make an individual determination based upon their experience and
judgement. Successful ambulation has been reported with either free
or locking hips joints; polycentric, stance-control, or locking knees;
and either articulated or solid-ankle foot mechanisms
47. PARTIAL HAND AMPUTATIONS
STATIC DEVICES
Most prosthetic devices used to restore grasp following partial-hand amputation have static configurations.
Particularly for use under the rugged conditions of factory work or manual labor, static designs have the
advantage of durability. Some are formed from stainless steel, individually shaped to the anomalous hand, and
covered with a pink-colored plastic (Plastisol) to increase the friction when gripping objects. Other devices are
made of laminated plastic formed over balsa wood or over lightweight aluminum armatures covered with
polyurethane foam . It is also possible to use thermoplastics to form partial-hand devices . Some amputees
choose to retain the simple utensil cuffs provided early in their rehabilitation training because they find this
approach adequate for their needs.
The common denominator in all these prostheses is that they must be individualized carefully to perform the
specific tasks desired by the amputee. For example, the configuration to permit a landscape worker to handle
shovels, rakes, and the like will differ significantly from the contours necessary to permit a chef to use cooking
utensils. It is usually helpful to have the amputee bring examples of the objects he wishes to handle with the
prosthesis to the initial fitting. This permits the prosthetist to reconfigure the prosthesis to provide as many
grasp patterns as possible prior to finishing the device.
48.
49. DYNAMIC DEVICES
Articulated or dynamic devices powered by residual motions at
the wrist or palm may also be developed to enhance grasp.
Although technically much more difficult to fit than static
designs, articulated partial-hand prostheses usually offer a wider
range of openings, thereby facilitating grasp of more varied
objects. It is sometimes useful to attach a prosthetic hook
mechanism to a hand remnant with no useful residual function.
Body power transmitted from biscapular abduction is generally
used to open the device, but wrist motion or other body
motions may sometimes be used . It is also possible to utilize a
voluntary-closing terminal device .
It is sometimes possible to combine a wrist-driven orthosis with
prosthetic fingers and thumb to result in a somewhat cosmetic
hand prosthesis, particularly when covered with a modified
cosmetic glove.
50. WRIST DISARTICULATION &
TRANSRADIAL AMPUTATION
An important decision to be made regarding the definitive electronic prosthesis is choice of the socket design.
Under ideal circumstances, the patient should have had the opportunity to try more than one type of socket
suspension at the time that the test sockets were being evaluated. This is particularly true of those patients who
are wrist disarticulation or long transradial amputees.
Socket designs for the transradial level fall into three basic categories:
(1) supracondylar brims that capture the humeral epicondyles and the posterior olecranon,
(2) sleeve suspensions that use either atmospheric pressure or skin traction to maintain suspension, and
(3) suprastyloid suspensions for wrist disarticulation amputees with prominent styloids.
51. Among the supracondylar designs there are four basic types. These are :
(1) the Miinster socket for short transradial amputations,
(2) the Northwestern supracondylar socket for midlength transradial amputations,
(3) the modified supracondylar brim with an olecranon cutout for long transradial amputations,and
(4) the floating-brim suspension for long transradial and wrist disarticulation amputations.
The sleeve suspension techniques include
(1) latex rubber sleeves, which provide atmospheric pressure suspension;
(2) neoprene sleeves, which provide a combination of atmospheric pressure and skin traction; and
(3) elastic sleeves, which provide skin traction/suspension.
The third category of suspension designs, i.e., those involving suprastyloid purchase, includes
(1) silicone bladder suspension,
(2) window/door suspension with elasticized closure, and
(3) soft removable inserts that grip the styloids.
54. ELBOW DISARTICULATION &
TRANSHUMERAL AMPUTATION
There are several factors that are crucial when designing and optimizing transhumeral and elbow disarticulation
prostheses, including the following:
Length of the bony lever arm
Quality and nature of soft-tissue coverage
Shape and muscle tone of the residual limb
Flexibility, range of motion, and stability of the proximal joints
55. SOCKET ALTERNATIVES
Prosthetic socket design is largely determined by the physical
characteristics of the residual limb. In the case of elbow
disarticulation, intimate fitting at and above the condyles provides
rotational control and suspension. Socket design alternatives are
analogous to those for the knee disarticulation or Syme ankle
disarticulation level and include the following:
Soft insert with an integral supracondylar wedge
Fenestration with a cover plate
Flexible bladder variants for the less bulbous remnants
"Screw-in"type sockets
56. UTAH DYNAMIC SOCKET
Over the past decade, experience in fitting significant numbers of externally
powered transhumeral prostheses has led to refinements in socket design and
harnessing techniques. The author has previously described the "Utah Dynamic
Socket technique" for transhumeral socket design, which is an outgrowth of the
previous work of Pentland and Wasilieff. Mediolateral stability is enhanced by
casting the remnant limb in a special fashion. Careful shaping of the shoulder
region adds rotational stability. The properly fitted dynamic socket does not
require socks for comfort or stability, although they may be worn if desired. This
socket design is suitable for either myoelec-trically controlled or body.
58. SHOULDER DISARTICULATION AND
FOREQUARTER AMPUTATION
In clinical practice two types of sockets are commonly
fitted at this level. These can be classified as those that
enclose the shoulder and are formed to its contours and
those incorporating some type of perimeter frame that
encompasses the shoulder and provides structural
mounting points for the prosthesis and location and
reference points for a variety of controls.
59. HARNESSING FOR SHOULDER PROSTHESIS
The provision of harnessing for the through-shoulder prosthesis
has two objectives. First, it is designed to hold the prosthesis in
place, minimize slip and movement on the stump, and spread
the weight of the prosthesis across the body. Second, by
utilizing differential body motion, the harness can provide
control inputs with force, speed, and displacement
components. The control element also provides some sensory
feedback if resistance to the motion is sufficiently large.