Test 1

Amputation Disparities Due to Age and Race

Non-whites approximately 42% of limb loss

African Americans with diabetes 2x higher amputation rate in 2008

Age: increased risk with increase in age

Greatest Causes of Amputation

1. Amputation Secondary to Peripheral Vascular Disease (PVD) & Peripheral Arterial Disease (PAD)

2. Secondary to Trauma

3. Secondary to Cancer

Most common cause of limb loss

Amputation Secondary to Peripheral Vascular Disease (PVD)

Common Peripheral Arterial Disease (PAD) Types

Diabetes Mellitus

Arteriosclerosis

Buerger’s disease

Diabetes Mellitus causing amputation

Leading cause of amputation = 154,000 / year

_ of diabetes-related amputations are preceded by a foot ulcer

85%

5 Year Mortality Percentage of Diabetic Foot Complications

Worst mortality outcome than breast cancer and all cancer

PVD/PAD: Arteriosclerosis

“hardening of the arteries”

Interrupted blood flow

Ischemic tissue

Amputation becomes necessary when ischemic tissue cannot be revascularized

PVD: Buerger’s Disease

AKA: thromboangiitis obliterans

First described - Buerger (1908)

Defined: acute inflammation and thrombosis (clotting) of arteries and veins

Affects the hands and feet Incidence: 20-40 y.o. male cigarette smokers

Buerger’s Disease Treatment

Complete cessation of smoking

Amputation: Secondary to Trauma

Second most common cause; 2% of amputations

45% of amputations due to injury including motor vehicle collisions, workplace accidents, sports injures, and military wounds

Severe fractures, non-union/malunion

Injury/insult to blood supply

Burns

• Electrical

• Thermal

Frostbite

Amputation Secondary to Cancer

Third most common cause; 2% of amputations

Congenital Limb Deficiency Prevalance

~ 1 in every 1,900 babies is born with a limb reduction defect in the United States.

Congenital Limb Deficiency Categories

1. Failure of formation of parts

2. Failure of differentiation

3. Duplication

4. Overgrowth

5. Constricting band syndrome

6. Skeletal abnormalities

Congenital Deficiency due to Thalidomide

Drug designed as sedative

Used to treat morning sickness in pregnant women (1950’s-1960’s)

Causes limb defects

Resurgence in Brazil (2005-2008)

Congenital Limb Deficiency: ISO/ISPO Classification

Know the concept I don’t think we need to name

Terms such as hemimelia, etc., are avoided due to their lack of precision and translation.

Anatomic and radiologic bases only

Name the bones affected in a proximal-distal sequence by using the name as a noun

State whether each affected bone is totally or partially absent

• Transverse

• Longitudinal

Any bone not named is present and of normal form

Less common causes of amputation

Cellulitis and Infections

Neurological Conditions

Spider/Insect Bite

Future Projections of Amputation

we have job security

3.6 million people living with an amputation by year 2050.

Numbers increase as the population ages and dysvascular disease increases.

Casting Technique for PTB traditional

2 stage

1. Anterior splint

2. Circumferential wrap

Casting Technique for PTB SC or PTB SCSP

3 stage

1. Anterior splint

2. Circumferential wrap

3. Proximal splint

Casting Technique for Hybrid PTB/TSB

2 stage (1-stage optional)

1. Anterior splint

2. Circumferential wrap

or

1. Circumferential wrap only

TSB Casting Techniques

1 stage (2-stage optional)

1. circumferential wrap

or

1. Anterior splint

2. Circumferential wrap

Casting Steps

1. Gather Casting Supplies

2. Circumferential Measurements

   1. if using gel liner, do them over liner

3. Applying the Casting Interface

   1. plastic barrier

   2. optional casting sock

4. Measure Prosthetics Side

5. Measure Non-Prosthetics side

6. Identify and Mark Landmarks

7. Take Impression (Cast)

What do you measure on prosthetic side when casting?

1. Residual Limb Length

2. Bony Length

3. ML

4. AP

5. Proximal ML (PML) for Supracondylar Suspension

What do you measure on non-prosthetic side when casting?

1. MTP to Floor Measurement

2. Anatomical Foot Measurement

When marking bony prominence have patient in _ degrees of flexion

20

to accentuate bony prominences

List of landmarks to identify and mark

1. Patella

2. mid patella ligament and both sides of the patellar ligament

3. Tibial crest

4. Anterior distal tibia

5. Tibial tubercle

6. Medial flare of the tibia

7. Medial shaft of the tibia where it transitions to soft tissue

8. Lateral tibial flare and lateral aspect of the crest of the tibia

9. Widest point of the medial and lateral condyles of the knee

10. Medial condyle of the knee and adductor tubercle if pronounced

11. Fibular head

12. Shaft of the fibula

13. Cut end of the fibula

14. From the patellar tendon level “0”, make a mark at one-inch intervals as far distal as possible (or transfer these one-inch interval marks from the tape underneath)

15. Iliotibial band (for supracondylar cast)

16. Adductor tubercle (for supracondylar cast)

17. Mark one inch proximal to the proximal border of the patella (supracondylar suprapatellar cast)

Landmark markings: Patella

Circle drawn around patella

• A in picture

Landmark markings: mid patella ligament and both sides of the patellar ligament

Mark as an “H” for us

• b in picture

Landmark markings: Tibial crest

A straight vertical line drawn directly down the sharpest edge of the shin bone

• e in picture

Landmark markings: Anterior distal tibia

where tibia ends

some draw a circle

• g in picture

Landmark markings: Tibial tubercle

prominence where patellar tendon inserts into the bony bump on the front of the shin

some people drawn upside down triangle or an oval directly

• c in picture

Landmark markings: Medial flare of the tibia

broad, flat, triangular shelf of bone on the upper, medial side of the shin

can trace the curve of your hand for it

• h in picture

Landmark markings: Medial shaft of the tibia where it transitions to soft tissue

line where your feel the edge of the tibia on the medial aspect

• i in picture

Landmark markings: Lateral tibial flare and lateral aspect of the crest of the tibia

in between tibia and fibula

Landmark markings: Widest point of the medial and lateral condyles of the knee

Feel the sides of the knee joint for the widest bony flares of the femur.

These points are wear you measure the ML

Landmark markings: Medial condyle of the knee and adductor tubercle if pronounced

Palpate the inner side of the knee joint to find the flat medial femoral condyle. Slide your fingers slightly upward and backward along the femur to feel for the small bony projection of the adductor tubercle. Circle it if it is pronounced.

Landmark markings: Fibular head

Circle around the prominent, round bony knob on the upper, outer side of the leg (below the joint line)

• d in picture

Landmark markings: Shaft of the fibula

Line on the outer bone ridge downward from the fibular head toward the bottom of the limb

Landmark markings: Cut end of the fibula

Circle very bottom tip of the outer bone

Because the fibula is cut shorter than the tibia during amputation, locate its exact terminal end and draw a small circle over it for pressure relief

• f in picture

Landmark markings: one-inch intervals

• patellar tendon level is “0”

• move distally

• this is where you measure circumferences

Landmark markings: Iliotibial band

• only for supracondylar cast

• palpate the thick, fibrous band of tissue running vertically down the outside of the thigh, inserting just below the knee. Mark its borders to ensure the high socket trim line accommodates its movement

Landmark markings: Adductor tubercle

• only for supracondylar cast

Landmark markings: one inch proximal to the proximal border of the patella

• only for supracondylar suprapatellar cast

• another 1in line just proximal this time

K0 Description

This patient does not have the ability or potential to ambulate or transfer safely with or without assistance and a prosthesis does not enhance their quality of life or mobility.

K1 Description

This patient has the ability or potential to use a prosthesis for transfers or ambulation on level surfaces at fixed cadence - a typical limited or unlimited household ambulator.

K2 Description

This patient has the ability or potential for ambulation with the ability to traverse low-level environmental barriers such as curbs, stairs, or uneven surfaces - a typical limited community ambulator

K3 Description

The patient has the ability or potential for ambulation with variable cadence - a typical community ambulator with the ability to traverse most environmental barriers and may have vocational, therapeutic, or exercise activity that demands prosthetic use beyond simple locomotion

K4 Description

The patient has the ability or potential for prosthetic ambulation that exceeds basic ambulation skills, exhibiting high impact, stress, or energy levels - typical of the prosthetic demands of the child, active adult, or athlete

K0 Foot/Ankle Assemblies and Knee Unit

Not eligible for prosthesis

K1 Foot/Ankle Assemblies and Knee Unit

Foot: External keel, SACH feet or single axis ankle/feet

Knee: Single-axis, constant friction knee

K2 Foot/Ankle Assemblies and Knee Unit

Foot: Flexible-keel feet and multi-axial ankle/feet

Knee: Single-axis, constant friction knee

K3 Foot/Ankle Assemblies and Knee Unit

Foot: Flex foot and flex-walk systems, energy storing feet, multi-axial ankle/feet, or dynamic response feet

Knee: Fluid and pneumatic control knees

K4 Foot/Ankle Assemblies and Knee Unit

Foot: Any ankle foot system appropriate

Knee: Any ankle knee system appropriate

Prosthetic Foot Basics Categories

1. Length

2. Heel height

3. Build height

4. Keel

5. Color, Toe style

6. Functional Level

Proper Foot Orientation

• top of the foot is parallel to the floor

  • plantar surface is not usually parallel to the floor

  • heel wedge must be inserted below the heel of the foot in order to maintain the top of the foot in the transverse plane

  • thickness of the wedge represents the heel rise of the foot

• the mid-patellar tendon to floor measurement is taken from the floor at the ball of the foot or at the heel under the heel wedge

Prosthetic Feet Types

1. SACH

2. Single Axis

3. Flexible Keel (K2)

4. Dynamic Response (K3)

5. Specialty

Prosthetic Feet Additional Features

1. Multiaxial

2. Torsion

3. Vertical Shock Absorbing

4. Integrated Vacuum for suspension

5. Heel Height adjustability

6. Hydraulic Ankle

7. Microprocessor Ankle

SACH Feet

• Solid-Ankle Cushioned-Heel

• most basic prosthetic foot available

• a rigid, non-deforming keel, but the heel is compressible

• K1

SACH Feet Types

1. Internal keeled

2. External keeled (discontinued)

3. Syme (discontinued)

4. Post Operative (discontinued)

SACH Feet Advantages and Disadvantages

• Advantages

  • Stable

  • Lightweight

  • Durable

• Disadvantages

  • No energy return

SACH: Post-Operative

• Used on post-operative prosthesis only

• Very soft foam covering, rigid keel

• No shoe to be worn with this foot

Single-Axis

• Articulated in sagittal plane to provide plantar and dorsiflexion

• K1

• available in both an endoskeletal and an exoskeletal version

• It incorporates a single-axis hinge at the ankle.

Single-Axis Bumpers

• available with differing firmness, making resistance adjustable

• Posterior Bumper (Plantarflexion Bumper):

  • Gait Phase: Initial contact → Loading response

  • Simulates: Eccentric dorsiflexors (tibialis anterior).

  • Function: Compresses to absorb heel strike shock and control the rate of plantarflexion to achieve rapid foot-flat, maximizing knee stability

• Anterior Bumper (Dorsiflexion Bumper):

  • Gait Phase: Midstance → Terminal stance / Toe-off

  • Simulates: Eccentric plantarflexors (gastrocnemius-soleus complex)

  • Function: Compresses to resist forward movement of the tibia (dorsiflexion), maintaining a stable toe lever for smooth progression and rollover

Single Axis feet Advantages and Disadvantages

• Advantages

  • Adjustable resistance

  • Increased knee stability at loading response (good for week quads)

• Disadvantages

  • Maintenance

  • Potential for noise (fix with garage door lube)

  • May be more difficult to cover

Flexible Keel Feet

• K2

• Simulated joint motion

• more ground compliant than those feet with rigid keels

Flexible Keel Foot Advantages and Disadvantages

• Advantages

  • Durable

  • More compliant than SACH

  • Easy “rollover” (progression from midstance to late stance)

• Disadvantages

  • No energy return

Dynamic Response Foot

• K3

• has a deformable spring-type keel that provides a lively, responsive feel while the patient is walking

• keel deforms under loading, it absorbs shock and then quickly returns to its original position once the load is removed

Advantages of Energy Return

• Increased self-selected walking velocity

• Increased stride length

• Decreased sound side weight acceptance force

• Increased prosthetic side propulsive force

Fiberglass vs Carbon

• both experience delamination and deterioration

  • fiberglass feet do not experience the same type of catastrophic failure as carbon fiber

• durability of fiberglass feet is an advantage

  • offer a different feeling of energy return that some patients report as “softer” or not as “bouncy” as carbon feet

Seattle Lightfoot Dynamic Response

• These feet have Delrin or similar composite keels

• They provide energy return, but minimal compared to other dynamic response feet

• K3

Split Keel Feature

• Provides Inversion Eversion motion to accommodate slightly uneven ground.

• Not a billable feature.

Dynamic Response vs. Flexible Keel

• Dynamic Response

  • Spring

  • Energy Storing / Energy Returning

• Flexible Keel

  • Sponge

  • Energy Absorbing

Additional Features

1. Multi-Axial

2. Vertical shock absorption

3. Heel height adjustability

4. Hydraulic

5. Microprocessor Control

6. Powered

Feature: Vertical Shock Absorption

• K3+

• allows the prosthesis to dampen the axial loading of the prosthesis and thereby decrease the shock transmitted to the residual limb

Feature: Multi-Axial Rotation

• K2 or K3

• can increase the base of support by accommodating uneven terrain

• Prosthetic joint simulation can be accomplished by true articulation of the prosthetic foot, as well as compression of the foot itself

Feature: Multi-Axial Rotation Advantages and Disadvantages

Advantages

• Accommodate variable terrain

• Energy return

Disadvantages

• Weight

• Noise

• maintenance

Feature: Heel Height Adjustability

• adjust the foot’s dorsi/plantar flexion position providing them the freedom to wear shoes of varying heel heights

• Only on dynamic response feet, k-3 and k-4

• Insurance doesn’t want to pay, can get on workers comp

Feature: Hydraulic Ankle

• K2 or K3

Microprocessor Ankle

• K3

• microprocessor-controlled and motor-powered dorsiflexion and plantar flexion during the swing phase

• make navigation of inclines, stair ascent and descent, and sitting onto or rising from a chair easier

Ankle Units

• that can be coupled with the prosthetic foot to provide the multi-axial feature in a foot that does not otherwise provide this motion

Activity Specific Feet

• Swimming foot

• skiing foot

• running feet

  • sprinting

  • jogging

• stompers

• rock climbing

SACH Foot Mechanic at Initial Contact

• soft heel cushion compresses under load

• compression simulates plantarflexion

  • musculature: simulates an eccentric contraction of the dorsiflexors

SACH Foot Mechanic in Stance phase

• keel does not deform, providing firm support for push-off

  • simulates an isometric contraction of the dorsiflexors

• Toe dorsiflexion is simulated by the rubber toe section of the foot distal to the keel

Patellar Tendon Bearing “PTB” Socket

Construction: Laminated or molded plastic socket

Intimate, total contact fit over entire residual limb

Anterior wall extends to encapsulate distal 1/3 of patella

Socket has a “bar” at the patellar tendon as a major weight-bearing surface

PTB Socket Design

• Medial and lateral walls extend proximally to adductor tubercle of femur to control mediolateral forces applied to residual limb

• Posterior wall is designed to apply anteriorly directed force to maintain the patellar tendon on the bar

• Distal end pad (DEP) and/or soft liner may be used when indicated for added protection and comfort

PTB Indications

Virtually all transtibial amputees

PTB Contraindications

• Extremely short residual limbs

  • may require the “bent-knee” prosthetic design

• Severe flexion contractures (beyond 45 degrees)

  • may require bent-knee prosthetic design

PTB Hard Socket Indications

• Mature residual limb with good soft tissue coverage and no sharp bony prominences

PTB Hard Socket Contraindications

• Skin coverage that is thin, scarred, grafted, or otherwise subject to breakdown

• Diabetes/Peripheral vascular disease (PVD)

• Sharp bony prominences

• A recent amputee

PTB Hard Socket Advantages and Disadvantages

• 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 precision in casting and modification

  • More difficult to fit to bony or sensitive residual limbs

  • Not as easily modified as a socket with a liner

PTB Socket with Soft Liner Indications

• PVD, thin, sensitive, or scarred skin

• Sharp bony prominences, peripheral neuropathy

• Noncompliant or unreliable patients, bilateral transtibial patients

• Highly active patients, blind patients

PTB Socket with Soft Liner Contraindications

• Patient rejection

PTB Socket with Soft Liner Advantages and Disadvantages

• Advantages

  • Provides a soft, protective socket interface

  • Is appropriate for the majority of residual limbs

  • Rebound in the liner may aid circulation by providing a "pumping action" and by providing intermittent pressure over bony prominences.

  • Easily modified

• Disadvantages

  • Not as hygienic as a hard socket because liner tends to absorb perspiration.

  • Increases bulk around the knee (the entire socket must be enlarged by approximately 1/4 inch)

  • May increase the weight of the prosthesis

  • The liner may compress and pack down over time resulting in loss of definition of the original modifications

  
  

PTB Design Variants

1. PTB

   1. proximal brim of the socket does not extend above the adductor tubercle

2. PTB-SC

   1. a self-contained suspension system requiring no additional straps, etc

   2. socket extends above the condyles of the knee

   3. shaded area marked out above the condyles is a supracondylar wedge

3. PTB-SCSP

   1. is self-suspending with the supracondylar wedge

   2. Socket extends above the condyles medially and laterally and also extends above the patella

      1. Just superior to the proximal border of the patella, the socket is modified with a slight indentation known as the quadriceps bar

Supracondylar Socket (PTB-SC) Indications

• Short residual limb

• Mild mediolateral instability

• Cannot tolerate cuff

  • due to scars

  • pinching during knee flexion

  • restricted circulation

Supracondylar Socket (PTB-SC) Contraindications

• Kneeling

• Obese or very muscular patients

• Cosmesis

• Moderate to severe ML instability

Supracondylar Suprapatellar Socket (PTB-SCSP) Indications

• Short residual limb

• Mild mediolateral instability or genurecurvatum

• Cannot tolerate cuff

  • due to scars

  • pinching during knee flexion

  • restricted circulation

Supracondylar Suprapatellar Socket (PTB-SCSP) Contraindications

• Kneeling

• Obese or very muscular patients

• Cosmesis

• Moderate to severe ML instability or genurecurvatum

Total Surface Bearing Designs (TSB)

• Disburses pressure evenly over entire residuum

• Uses gel insert (locking or non-locking)

  • Sleeve-type suspension

  • Locking pin suspension

  • Suction suspension

  • Vacuum-Assisted Suspension