below knee prosthesis department of orthotics and prosthetics prosthesis mahmood bahramizadeh
TRANSCRIPT
Below Knee prosthesis
Department of Orthotics and Prosthetics
prosthesis
Mahmood Bahramizadeh
History
The earliest recorded use of a limb prosthesis is that of a persian soldier, Hegesistratus. (Herodotus).
The oldest known artificial limb in existence was a cooper and wood leg. 300B.C.
Partial foot amputation
Vascular disorders and trauma are the major causes of lower limb amputation.
Prediction of healing is the most important part of level selection.
As a general rule, all length possible should be saved.
Types of prosthesis
1. Postoperative pros.2. Initial pros.3. Preparatory pros.4. Definitive pros.5. Special use pros.
Postoperative pros
Provided within 24 hours of amputation.
Most commonly prescribed for the younger, healthier individual.
Acronyms: IPSF: immediate postsurgical fitting. IPOP: immediate postoperative prosthesis.
Initial pros.
Provided as soon as the sutures are removed.
Due to the usual rapid atrophy of the residual limb, is generally directly molded on the residual limb by using plaster of paris or fiberglass bandage.
Acronyms: EPSF: early postsurgical fitting.
Initial pros.
1 to 4 weeks after amputation. Until the suture line is stable and the skin can tolerate the stresses.
Preparatory pros. Used in cases to assess ambulatory or
rehabilitation potential and help clarify details of the prosthetic prescription.
Used a few days following suture removal.
Lacks the protective and cosmetic. It used until stump matures. Used to optimize alignment. Used 3 to 6 months following the date of
amputation.
Preparatory pros.
Amputees may wearing ten plies of prosthetic socks to compensate for atrophy.
Definitive pros.
Residual limb has stabilized to insure that the fit of the new prosthesis will last as long as possible.
The average life span for a definitive prosthesis is from 3-5 years.
Special use pros.
A certain number of patients will require for such activities as swimming, skiing.
Phalangeal complete
Phalangeal complete Great toe
amputation does not affect standing or walking at a slow or moderate pace.
Amputation of the second toe result in severe hallux valgus.
Prosthesis
Sponge rubber or foam is usually inserted into the tip of the shoe.
A long steel spring shank can be used in the sole of the shoe to assist push off and prevent deformity of the shoe.
Amputation of all toes
Clawing of toes. Severe hallux valgus Painful metatarsophalangeal
dislocation.
Prosthesis An insole is used for
supporting the metatarsal to relieve weight from the metatarsal heads.
A cavus support for the high arch.
A cork or foam toe block is attached distally as a filler.
Prosthesis A rocker sole may
be necessary to replace the action of rocking forward on the foot.
The sole can be stiffened with a long steel spring.
Metatarsal ray resection
Metatarsal ray resection Congenital
anomalies. Gangrene Chronic infection.
Transmetatarsal amputation Vascular disease Diabetic ischemia
Transmetatarsal amputation
Prosthesis The break is an
ordinary shoe is at the metatarsophalangeal joints.
The vamp of the shoe may irritate the top of the stump, resulting in sores.
Adding the steel spring between inner and outer sole.
Prosthesis Adding a rocker
bottom. Without support in
the front of the bottom the patient will display a limp as walking speed increases.
Lisfrance. (M.T complete). In the growing child
where it is desirable not to interfere with the distal tibial epiphysis and yet to allow end bearing.
In individual who do heavy labor or farm work.
Lisfrance. (M.T complete). Problems:1. A fixed equinus
deformity may result from a loss of the distal attachment of the dorsiflexors.
Prosthesis Shoe filler:
weight bearing will be on the plantar heel skin.
If only a shoe filler is used the toe break is located more proximal than in the normal foot.
Prosthesis Rigid plate :if an equinus deformity
that can be passively corrected is present, for prosthetic stabilization is necessary.
Attached to shank piece that goes above the calf.
Prosthesis Steel spring
with heel cup: Extends out to the
toe and posteriorly to form the heel cup.
Review
Chopart
Chopart Through the
talonavicular and calcaneocuboid joints.
Is recommended for neuropathic lesions.
Chopart Problems: equinovarus
Prosthesis Boot with toe
filler: nothing to improve the gait over walking barefooted.
Rub the end of the stump, causing pressure and ulceration.
Prosthesis Boot with
semirigid metal sole and toe filler:
From mid-stance until toe-off a long steel spring shank assists push-off by resisting the forces acting to dorsiflex the forefoot.
Prosthesis A.F.O:A posterior leaf spring
AFO.Resistance to plantar
flexion at heel strike.Allowing a slow descent
of the foot.Resist dorsiflexion and
assist push-off from mid-stance to toe-off.
Prosthesis
Chopart prosthesis:is almost identical to the syme
prosthesis in fabrication. Unlike the syme amputation, there
is no distance between the end of the residual limb and floor with the chopart.
Pirogoff amputation Calcaneal fragment-
tibia arthrodesis End-bearing stump. Advantages:1. End-bearing2. Walk with less limp3. The heel flap does
not wobble as it may do on the syme limb.
Prosthesis
Shoe filler. PUSH OFF IS LOST
Thick shoe sole with soft padding PUSH OFF IS LOST
PLS AFO
Boyd amputation Calcaneotibial
arthrodesis. Prosthesis= syme
Syme
Ankle disarticulation. The advantages of the Syme over
below knee amputation:1. Decreased risk of serious hemorrage2. Decreased mortality3. A more comfortable limb4. A more useful limb for W.Bearing.5. Function is enhanced by limb length.
Syme
Bilateral syme amputee walk with a better gait and can stand longer than bilateral below knee.
Phantom Pain is rare after a syme amputation.
Syme
Prosthesis
The syme amputation has had only limited popularity until recently, at least in part because of the difficulty of providing a suitable prosthesis.
Syme pros. Should have durability especially in the ankle region.
Historic syme pros.
Historic syme pros. Front lacing leather
socket. Strong steel frame
forms medial and lateral uprights that reinforce the leather.
The tightness of the the thigh-lacer provides a means of adjusting the relative distribution of weight bearing between the proximal and distal aspects of the limb.
Historic syme pros. A single-axis joint. Uncosmetic Heavy Used in countries
where plastic laminates are unavailable.
Canadian syme pros. A posterior door
that extends to the brim of the socket allows insertion of the limb and then is bulked into place into place for closure.
Veterans administration syme pros.
Veterans administration syme pros.
Medial window. Enhances the
mechanical strength of the prosthesis over the canadian syme.
Some weight bearing occurs along the proximal trim lines.
Casting at 10 degrees flex.
Veterans administration syme pros.
Suspension:1. Circumference
proximal to the bulbous end.
2. Auxiliary suspension: femoral condyle strap.
Elastic liner syme prosthesis
Elastic liner syme prosthesis
Closed, Expandable socket.
Miami syme prosthesis
Window less prosthesis.
Elastic liner syme prosthesis
Cosmetic Stronger than
canadian and VAPS.
Foam is compressed as the limb is pushed into the prosthesis.
Socket foot junction
The weakest point in the prosthesis
Shearing force at push off
Ankle/ Foot Mechanisms
Single axis Multiple axis
Single Axis
Dorsiflex. (5 to 7) and plantarflex. (15)
No mediolateral or transvers rotary motion.
May become noisy. Heavier than SACH Less cosmetic than the SACH
Single axis
1.Wooden foot (historic)Flexible soleToe break should be far enough forward and back : for stability and smooth transition from stance to swing phase.
Single axis
Durable Easily repairedLittle shock absorptionSocks catchToe break is in one plane.
Variation of the wooden foot
Multiple axis (functional) ankleArticulated assemble Cable: flexible cable
between the foot and shank. Movement occurs in any direction.
Otto bock universally movable Greissinger
Non Articulated assemble
Solid ankle cushion heelPost operative flat heeled foot
LitefootVeterans administration/ kingsley Beachcomber foot
Stationary attachment flexible endoskeletal (SAFE)
Articulated assembles
Mediolateral and torsional forces are reduced (absorption).
Accommodates well to uneven ground.
Less cosmetic than single and SACH
Articulated assembles Otto bock
Greissinger foot:Can be used for
above knee and below knee.
More cosmetic and lighter in weight than cable.
Non articulated SACH: Shock absorption
and motion provided by the material and structure.
Non articulated Heel wedge
compresses at heel strike
The shape and length of the wooden keel provide the smooth rocker motion and support.
Foam rubber sole and nylon belting resistance to toe extension.
External keel provide more stability than internal keel.
SACH The arch should
provide at least 0.3 cm (1/8 in) clearance between the foot and shoe.
The lower third of the SACH foot heel should fit snugly into the heel counter.
SACH
Variations of the SACH
Syme foot: 2.5 cm (1in). The keel is larger and wider for
stability and durability. The stud bolt is reversed to
prevent any potential irritation.
Variations of the SACH Hi-heel SACH foot;
Variations of the SACH Sculptured toe
SACH foot: In various heel
height and firmnesses
Non articulated Post operative flat heeled
foot; For immediate prosthesis Good lateral stability The weight 20 percent less
than the regular molded foot.
Resistance to the toe break is less than standard SACH.
Used for swimming and water skiing.
Used with flat heeled shoes such as tennis shoes.
Non articulated
Lite foot: Lighter and softer than the regular
SACH For early ambulation and for a
definitive porsthesis.
Non articulated Veterans
administration/kingsley Beachcomber foot:
Waterproof Can locks at 120
degrees for swimming.
Non articulated
Non articulatedStationary attachment flexible endoskeletal (SAFE):Like windlass effectAt heel off the bands tithens to create a semirigid toe lever.Flexible keel is used to adapt in irregular surfaces.Long plantar ligament band span the arch to stabilize that when wearer stand.
Non articulatedThe anterior surface of the Bolt Block is cut at 50 degrees and the inferior surface is rounded to provide a subtalar- like surface.It has no mechanical joint.
Axial rotation device
This device is used to absorb the torque and shearing force and provide the wearer to be safe of skin abrasion and allows the socket to rotate independently of the foot position.
Advantages of B.K as opposed to A.K
Mortality is lower. Much better prospect of prosthetic
rehabilitation. Phantom limb is lower.
Prosthesis Historic below
knee: Consists of a leather
thigh corset + side bars+ open ended socket.
Weight bearing is carried on the residual limb and through the suspension mechanism.
Historic below knee (advan.)
The thigh corset supports some of the weight bearing.
Prevent hyperextension at the knee.
Provides lateral-medial stability.
The socket is cooler than the total contact PTB because of lack of total contact pressure.
Historic below knee (disadvanta.)
Edema Bulky and heavily Uncosmetic Atrophy Relative motion
causing irritation. Ischemia The hinge breaks
frequently. No normal gait.
Slip socket Design to minimize
relative motion between the socket and skin.
The socket is either elastically suspended from the sidebars or is attached to shank by a compression spring.
The socket can rotate and piston up and down.
Slip socket Is used for only
for those people with short or tender limb.
Slip socket
Advantages: The amputee with
the slin graft can ambulate early.
It preserves the knee joint.
Slip socket Disadvantages: Uncosmetic. Bulky and heavy Produce atrophy. Tear of clothing. Walk more like an
A.K amputees.
P.T.B Was developed at
the university of california (1959).
More intimate fit and more efficient than historic.
P.T.B
Advantages: Total contact
design.1. Improve
circulation2. Prevent edema3. To distribute the
W.B.4. Better
proprioception.
P.T.B Lighter than the
historic. More freedom of
movement than the thigh corset.
More cosmetic gait. Gait looks ssentially
normal except for the lack of push off.
P.T.B More cosmetic. Easier to don and
remove. Require less time
for fabrication.
P.T.B
DisAdvantages: Require more critical
fit Excessive perspiration There is a tendency
for the amputee to hyperextend the knee.
Frequent readjustments may be necessary.
Shank
Connect the ankle/foot assembly with the socket in a specific alignment.
Weight bearing areas
Weight bearing areas
Modification of the positive
Posterior brim
The posterior brim is generally 0.6 to 1.3 cm (1/2 to ¼ in) higher than the patellar shelf tendon shelf.
For very short limbs the posterior brim may be so high that flexion is limited to 60 degrees.
modification
modification
modification
Anterior brim
The anterior brim comes to the midpatellar level.
Medial and lateral brim
M-L brims come to about the level of the proximal edge of the patella.
The proximal aspect of the medial and lateral walls support the femoral condyles and are usually 6.5 cm (2.5in) above the medial tibial plateau in height.
Non-weight bearing areas
Hard socket The hard socket may or may not have a distal
pad. Advantages:1. Less problem with perspiration.2. Easy to clean3. Less bulk at knee4. Fabrication time is less5. More intimate fit than with an insert. Disadvantages:1. More difficult to fit2. Less adjustability
Soft insert socket
Soft inserts are used between the hard socket and the limb.
Advantages:1. Less difficult to fit2. Possible added comfort3. Can make donning easier
Soft insert socket
Disadvantages:1. Hot2. Poor hygiene3. More weight4. Some sacrifice of stability.
Ultralight below knee A completely
crustacean PTB Exoskeletal type can
be much lighter in weight while providing the same strength.
The outer structure is farther from the axis and thus has a longer lever arm.
Ultralight below knee Socket:P.P Is vacuume-formed. Foot:A sole and heel cushion
like that used with any SACH can be used for it
Waterproof: the presence of buoyancy causes a problem during swimming
Ultralight below knee Advantages:1. Require less
energy to walk.2. Less pistoning 3. Can be worn in
and around water
Ultralight below knee DisAdvantages:1. Not durable2. Defficult to
modify
Bent- knee prosthesis Is used in cases of
irreducible knee flexion contractures.
A plaster negative is made of entire limb from well up on the lower third of the femur with the knee joint in maximum extension.
Bent- knee prosthesis External knee joint Weight is borne
through the remaining portion of the tibia, patellar tendon, thigh cuff.
Durable cheap
Bent- knee prosthesis Is required because of
poor skin condition, limited weight bearing capability, or limited knee function.
Cuff suspension Suspends the
prosthesis during swing phase.
Checks against knee hyperextension.
Cuff suspension Atrophy does not
occur. Does not create
relative motion. Not bulky. More cosmetic.
Cuff suspension Does not give M-L
stability. Uncosmetic when
sitting Positioning of
studs is critical.
Forks, jack, or inverted Y strap to a waist belt
Is used for disvascular amputee. When hip is extended and the knee
is flexed during walking, the fork is under tension and acts to extend the knee and bring the shank forward.
Forks, jack, or inverted Y strap to a waist belt
Good auxiliary suspension. Uneven suspension through swing
phase.
Suspension prosthesis (PTS) Sc/sp .
Pts: prosthese-tibiale-supracondylienne.
Better M_L stability.
The patellar shelf is less pronounced in the PTS than in the PTB.
Suspension prosthesis (PTS) Sc/sp .
For short stump: <7.5cm.
Knee instability due to lig. And muscle dysfunction.
Suspension prosthesis (PTS) Sc/sp .
Less restrictive. Easier to don. Prevents genu
recurvatum. More cosmetic.
Suspension prosthesis (PTS) Sc/sp .
The prosthesis tend to slip down when the knee is flexed 90.
Patellar enclosure may inhibite extreme knee flex.
Is not suitable for long stump.
Difficult for obese limb.
Supracondylar wedge suspension
Supracondylar wedge suspension
Supracondylar wedge suspension
Detachable medial brim
Molded rubber sleeve suspension
Rolled or pulled up to cover 5 to 10 cm (2 to 4 in) of the thigh above the stump.
Do not