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PassPMR - 08 Prosthetics & Orthotics > 5. Lower Limb Prosthetics > Flashcards

5. Lower Limb Prosthetics Flashcards

1
Q

Descriptions of Level of Amputation in the Lower Limb 🔑🔑 EXAM

A

💡 Upper Limb 100-55-35 & 90-50-30-0
Lower Limb 90-50-20 & 60-35-0

Cuccurollo 4th Edition Chapter 6 P&O pg479

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2
Q

3 Unsatisfactory levels in LL amputations 🔑🔑 Dr. Jamal

A
  1. Distal two-fifths of tibia (below gastroc-soleus musculature)
    • Difficulties of good skin and soft tissue management.
    • Inadequate muscle coverage for the distal tibia.
    • Advice: amputee at 3/5 of the tibial length at GS muscle
  2. Very short below-the-knee amputation (BKA) proximal to the tibial tubercle
    • Knee extension strength is lost
    • Knee becomes of no value for stability and ambulation.
    • Difficulties in prosthetic fit.
    • Advice: least 1 cm below the tibial tubercle or go for knee disarticulation.
  3. Very high above-knee amputation (AKA)
    • Limb tends to develop excessive flexion and abduction at the hip joint.
    • Socket fit may become a difficult problem
    • Advice: leave a short segment of femur rather than amputate at the hip disarticulation level.

Cuccurollo 4th Edition Chapter 6 P&O pg480

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3
Q

Energy expenditure of transtibial unilateral (vascular/traumatic) level of amputation🔑🔑 EXAM

A

VASCULAR

BL V. Transfemoral = 120

UL V. Transfemoral = 90

BL V. Transtibial = 100

UL V. Transtibial = 33

BL V. Ankle = 40

TRAUMATIC

UL Transfemoral, Knee & BL Transtibial = 30-33

UL Transtibial = 7

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4
Q

Functional levels of ambulation for amputees 🔑🔑 You have got a consultation letter asking you to assess a 25 years old gentleman with a history of right above knee amputation with no other medical problems. You wrote a letter to the referring doctor that the patient is level K4 according to the Medicare Guidelines for functional classification of patient with prosthesis. What does K4 mean? (1 mark)

A

K0

No ability to ambulate or transfer with use of a prosthesis

Prosthesis does not enhance the quality of life

Rx: cosmetic prosthesis

K1

Limited house ambulation at fixed cadence

Traverse level surfaces

Foot: SACH or single-axis foot

Knee: manual lock or stance control

K2

Limited community ambulation with fixed cadence and limited distance

Traverse low level environmental barriers

Foot: multi-axis foot or flexible keel

Knee: stance control (braddom) vs pneumatic or polycentric knee (cuccu)

K3

Unlimited community ambulation with variable cadence and unlimited distance

Traverse most environmental barriers

Foot: multi-axis foot or energy storing

Knee: hydraulic, pneumatic or microprocessor

K4

Functional ability exceed normal ambulation activities

Prosthesis is required for high impact, stress, or energy levels

Foot: energy storing or speciality foot

Knee: hydraulic

Cuccurollo 4th Edition Chapter 6 P&O pg485

Braddom 6th Edition Chapter 10 LL Prosthetics pg182 Table 10.2

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5
Q

List 4 contraindications for fitting a geriatric patient with a prosthesis 🔑

A
  1. Low vision
  2. Poor cognitive
  3. Severe cardiac disease (Low ejection fraction)
  4. Sensory loss
  5. Functional level K0
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6
Q

Toe disarticulation. (ALC Clinic) 🔑🔑

Indication & Contraindication, Advantages & Disadvantages, Management.

A

Indication

Mostly seen in the vascular patient, including arterial sclerosis and diabetes.

Contraindication

Poor vascular supply to the rest of the foot would lead to continuous progression of amputations up to the transtibial level.

Advantages

Near normal gait pattern compared to a transmetatarsal amputation (TMA).

Disadvantages

Nill

Management

Toe fillers

Cuccurollo 4th Edition Chapter 6 P&O pg480

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7
Q

How do you prescribe suitable prosthesis for partial foot amputation. (ALC Clinic)🔑🔑

A

Small toe amputation

  • Do not affect ambulation and usually require no prosthesis.

Amputation of the great toe

  • Reduces push-off force, thus requiring a stiff sole and toe filler with molded insole with arch support to maintain the alignment of the amputated foot.

Partial foot amputations

  • Require shoe fillers or shoe modifications

Cuccurollo 4th Edition Chapter 6 P&O pg486

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8
Q

Trans-metatarsal amputation. (ALC Clinic) 🔑🔑 Indication & Contraindication, Advantages & Disadvantages, Management.

A

Indications

  1. Trauma to the toes
  2. Loss of tissue due to an infection, or gangrene due to frostbite, diabetes, arterial sclerosis, scleroderma, Buerger’s disease
  3. Gangrene must be limited to the toes
  4. Infection should be controlled.

Contraindication

  • Not indicated in cancers of the metatarsal bones because it would not be conclusive that all bony cancer would have been resected

Advantages

  • Preserves the attachment of the dorsiflexors and plantar flexors and their function.
  • Minor functional loss during stance and walking on level surfaces.

Disadvantages

  • Nill

Management

  • Fitted with sole stiffeners and toe fillers

Cuccurollo 4th Edition Chapter 6 P&O pg480-481

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9
Q

How do you prescribe suitable prosthesis for transtarsal amputation. (ALC Clinic)🔑🔑

A

Cuccurollo 4th Edition Chapter 6 P&O pg486

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10
Q

Patient underwent forefoot amputation due to tumor growth, amputation was at ankle articulation with attachment of distal heel pad to the end of tibia. Name the amputation. 🔑🔑

A

Syme’s Amputation

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11
Q

Syme amputation 🔑🔑 Definition, Indications & Contraindication, Advantages & Disadvantages.

A

Definition

  • Ankle disarticulation with attachment of the distal heel pad to the end of the tibia
  • May include removal of the malleoli and/or distal tibial/fibular flares.

Indications

💡 Healthy plantar heel skin is necessary for weight bearing in this area.

  1. Trauma of the foot (labour job)
  2. Congenital anomalies (peds)
  3. Tumors (peds)

Contraindication

  • Dysvascular patient due to poor perfusion

Advantages

  1. Maintains the length of the limb
  2. Preservation of the heel pad, providing an excellent weight-bearing
  3. Early partial weight bearing of prosthesis is possible
  4. Early fitting of prosthesis is possible

Disadvantages → just like any joint disarticulation

  1. Poor cosmesis (bulbous, bulky residual limb)
  2. Fitting for a prosthesis may be more difficult
  3. Difficult procedure for the dysvascular patient
  4. Revision to transtibial amputation is common

Cuccurollo 4th Edition Chapter 6 P&O pg481

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12
Q

How do you prescribe suitable prosthesis for syme amputation.

A

Cuccurollo 4th Edition Chapter 6 P&O pg486

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13
Q

What are the types of prosthetic feet?
Major categories of prosthetic feet.

A

Nonarticulated

  • Solid ankle cushion heel (SACH) foot
  • Solid ankle flexible endoskeleton (SAFE) foot

Articulated

  • Single-axis foot: plantarflexion/dorsiflexion
  • Multiaxial foot
  • Hydraulic

Energy storing/dynamic elastic response

  • Low profile
  • High profile
  • Microprocessor control
  • Microprocessor control with internal power
  • Special activity feet

Braddom 6th Edition Chapter 10 LL Prosthetics pg188 Box 10.6

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14
Q

Name (1), Use, Advantages and Disadvantages

A

SACH (SOLID ANKLE CUSHION HEEL)

Level: K1

Advantages

  1. Durable
  2. Reliable
  3. Lightweight
  4. Inexpensive

Disadvantages

  1. Energy consuming
  2. Rigid
  3. Poor accommodation to uneven surfaces.

Cuccurollo 4th Edition

Chapter 6 P&O pg489 Table 6-10

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15
Q

Name(2), Use, Advantages and Disadvantages

A

SAFE (STATIONARY ANKLE FLEXIBLE ENDOSKELETON)

Level: K2

Pros:

  1. Multidirectional motion (Mimics multiaxis movement)
  2. Less maintenance than mechanical multiaxis foot
  3. Ambulation on uneven surfaces
  4. Absorbs rotary torques
  5. Smooth rollover
  6. Moisture and grit resistant

Cons:

  1. Heavy
  2. Increased cost
  3. Not cosmetic
  4. Does not offer inversion/eversion

Cuccurollo 4th Edition Chapter 6 P&O pg489 TABLE 6-10

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16
Q

Name (1), Use, Advantages and Disadvantages

A

SINGLE AXIS PROSTHETIC FEET

Level: K1-K2

  • Adjustable internal rubber bumpers that provide resistance to dorsiflexion and plantar flexion.

Advantages

  1. Movement in one plane (dorsiflexion and plantar flexion)
  2. Adds stability

Disadvatnages

  1. Increased weight (70% heavier than SACH)
  2. Increased cost
  3. Increased maintenance (internal components need periodic adjustment or replacement)

Cuccurollo 4th Edition Chapter 6 P&O pg489 Table 6-10

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17
Q

Name (2), Use, Advantages and Disadvantages

A

MULTI AXIS PROSTHETIC FOOT

Level: K2-K3

Pros:

  1. Allow PF (plantarflexion), DF (dorsiflexion)
  2. Inversion, eversion, and rotation
  3. Ambulation on uneven surfaces
  4. Relieves stress on skin and prosthesis

Cons:

  1. Relatively bulky
  2. Heavy
  3. Expensive
  4. Increased maintenance (especially in the very active amputee)
  5. Increased instability in patients with ↓ coordination

Cuccurollo 4th Edition Chapter 6 P&O pg489 Table 6-10

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18
Q

Name (1), 2 advantages and 2 disadvantages

A

HYDRAULIC MICROPROCESSOR PROSTHETIC FEET

Level: K3-K4

Advantages

  1. Propulsive microprocessor feet provide actively powered dorsiflexion and plantarflexion during both stance and swing phase.
  2. Reduce the energy cost of ambulation

Disadvantages

  1. Heavy
  2. Cannot get wet
  3. Need to be recharged at least daily.

Cuccurollo 4th Edition Chapter 6 P&O pg490 Table 6-10

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19
Q

Name (2-3), Use, Advantages and Disadvantages

A

STEN (STORED ENERGY) - LOW PROFILE

Level: K3-K4

Pros:

  1. Smooth rollover needed
  2. Elastic keel
  3. Moderate cost
  4. ML stability similar to SACH

Cons:

  1. Moderate-heavy weight
  2. Cannot be used with Syme’s amputation

SEATTLE FOOT - HIGH PROFILE

Level: K4

Consists of a cantilevered plastic C- or U-shaped keel, which acts as a compressed spring

Pros

  1. Jogging, general sports
  2. Conserves energy (Energy storing)
  3. Smooth rollover

Cons

  1. High cost

Cuccurollo 4th Edition Chapter 6 P&O pg490 Table 6-10

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20
Q

Name, Use, Advantages and Disadvantages

A

FLEX (WALK, RUN, FOOT) - ENERGY STORING FOOT / DYNAMIC RESPONSE

Level: K4

Running, jumping, vigorous sports, conserves energy.

Pros like race car

  1. Very light
  2. Most stable mediolaterally (ML)
  3. Most energy storing
  4. Less energy consumption
  5. Lowest inertia (errors)

Cons

  1. Very high cost
  2. Alignment can be cumbersome

Cuccurollo 4th Edition Chapter 6 P&O pg490 Table 6-10

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21
Q

Transtibial / Below-Knee Amputation (BKA) 🔑🔑 Appropriate length, Advantages over AKA, Advantages of Long BKA

A

💡 Preservation of the knee joint means preservation of a near-normal lifestyle with minimal physical limitations. Elderly amputee, saving the knee may well mean the difference between being able to walk or being confined to a wheelchair.

Transtibial Amputation/Below-Knee Amputation

  • Length should be 3/5 or 60-70% of the tibial length to preserve limb length with viable skin and muscle for distal coverage.
  • Tibia should be beveled anteriorly.
  • Fibula should be cut 2 to 3 cm shorter than the tibia

Advantages ove AKA

  1. Higher healing rates and better tissue viability
  2. Better weight-bearing surfaces.
  3. Decreased mortality
  4. Decreased energy expenditure.
  5. Preservation of the knee joint
  6. Near-normal lifestyle with minimal physical limitations

Benefits of longer amputee in BKA.

  1. Greater leverage & strength
  2. Lower energy cost
  3. Better ambulation
  4. Better proprioception

Cuccurollo 4th Edition Chapter 6 P&O pg481-482

21
Q

Transtibial / Below-Knee Amputation (BKA) 🔑🔑 Appropriate length, Advantages over AKA, Advantages of Long BKA

A

💡 Preservation of the knee joint means preservation of a near-normal lifestyle with minimal physical limitations. Elderly amputee, saving the knee may well mean the difference between being able to walk or being confined to a wheelchair.

Transtibial Amputation/Below-Knee Amputation

  • Length should be 3/5 or 60-70% of the tibial length to preserve limb length with viable skin and muscle for distal coverage.
  • Tibia should be beveled anteriorly.
  • Fibula should be cut 2 to 3 cm shorter than the tibia

Advantages ove AKA

  1. Higher healing rates and better tissue viability
  2. Better weight-bearing surfaces.
  3. Decreased mortality
  4. Decreased energy expenditure.
  5. Preservation of the knee joint
  6. Near-normal lifestyle with minimal physical limitations

Benefits of longer amputee in BKA.

  1. Greater leverage & strength
  2. Lower energy cost
  3. Better ambulation
  4. Better proprioception

Cuccurollo 4th Edition Chapter 6 P&O pg481-482

22
Q

Knee disarticulation Advantages & Disadvantages

A

Advantages (just like any joint disarticulation)

  1. Less traumatic to tissue
  2. Blood loss is minimal
  3. Long, strong residual limb
  4. Excellent end-bearing

Disadvantages

  1. Long flaps are necessary and healing may be impaired in the dysvascular patients
  2. Inability to provide a prosthesis that is functional and cosmetic.(any disarticulations)

Cuccurollo 4th Edition Chapter 6 P&O pg482

23
Q

Components of Transtibial / Below Knee Amputation (BKA) prosthesis 🔑🔑

A
24
Q

25 years old male patient with traumatic transtibial amputation. You see him in your OPD for prosthetic fitting. What would be the pressure tolerant areas in transtibial socket? 🔑🔑 EXAM Which side would you tilt the socket? Why?

A
25
Q

List 4 causes of lose fit of socket or liner. (ALC Clinic) 🔑

A
  1. Fluid shifts associated with renal function or dialysis
  2. Muscle atrophy
  3. Weight gain or loss
  4. Congestive heart failure.
26
Q

Socket is aligned on the shank on slight flexion (about 5 degrees). Why?

A

💡 Max of 25 degrees of flexion is possible to accommodate knee flexion contracture

Cuccurollo 4th Edition Chapter 6 P&O pg487

27
Q

BKA Suspension System 🔑🔑 MOCK

A
28
Q

Types of suspensions in Transtibial Amputation / Below Knee Amputation (BKA) 5 marks 🔑🔑

A

1. Pin Lock Suspension

Silicone or gel liner with an attached distal pin that locks into the socket.

Audible click to re-enforce engagement of the lock

2. Rubber or neoprene sleeve

Primary suspension system or in combination with another suspension mechanism.

3. Suction Suspension +/- Elevated vacuum socket systems

Silicone or gel liner with the use of a one-way valve in the distal aspect of the socket.

One-way valve allows air to escape from the socket.

4. Supracondylar cuff strap

Consists of a cuff that wraps around the thigh, fitted above the femoral epicondyles

With or without a fork strap and waist-belt suspension

5. PTB Cuff strap waist belt and billet or Waist belts with an anterior fork strap

6. Thigh corset

Leather corset to a PTB prosthesis through metal joints and side bars to decrease distal residual limb weight bearing by 40% to 60%

Cuccurollo 4th Edition Chapter 6 P&O pg488

Delisa, 4th edition, part2, p1334,p1335

29
Q

4 Advantages and 4 Disadvantages of liners (ALC Clinic)

A

Advantages

  1. Cushion for the residual limb
  2. Relief pressure on body prominence
  3. Allow for adjustment when residual limb volume changes
  4. Allow healing for scar

Disadvantages

  1. Heat retention
  2. Smelly odors
  3. Added bulkiness
  4. Frequent replacement due to wear and tear
30
Q

4 Advantages & Disadvantages of Suction suspension 🔑

A

Advantages

  1. Greater suspension demands need by athletes
  2. Better pressure distribution, does not create uneven pressure distribution
  3. Excellent skin protection
  4. Assists vascular inflow by creating a negative pressure

Disadvantages

  1. Expensive
  2. Gel liners are typically replaced annually
  3. Not always tolerated
  4. excessive sweating
  5. Need constant volume to ensure suction ( fit If volume ↑, it will prevent fit. If volume ↓, result is loss of suction)

Cuccurollo 4th Edition Chapter 6 P&O pg488

31
Q

4 Advantages & Disadvantages of Locking liner suspension 🔑

A

Advantages

  1. Secure suspension
  2. Improved proprioception
  3. Absorbs moderate impact
  4. Improved appearance

Disadvantages

  1. Expensive
  2. Gel liners are typically replaced annually
  3. Excess perspiration
  4. More complicated to don
  5. Some do not tolerate constriction of the liner

Cuccurollo 4th Edition Chapter 6 P&O pg488

32
Q

List 2 Disadvantages of Neoprene Sleeve.

A
  1. Increased perspiration
  2. Poor ML knee stability
  3. Poor hyperextension control.
33
Q

List 4 indications for use of thigh corset

A

💡 Pressure off knee - lateral metal and posterior too.

  1. Secondary suspension
  2. Poor skin condition
  3. Painful knee joint
  4. Compensate for collateral ligament
  5. Prevent genu recurvatum
  6. Added mediolateral support
34
Q

Knee unit for knee disarticulation.

A

FOUR BAR POLYCENTRIC KNEE

  1. Center of rotation is proximal and posterior to the knee unit itself.
  2. Greater knee stability
  3. More symmetrical gait
  4. Equal knee length when sitting.
35
Q

Transfemoral Amputation/Above Knee Amputation 🔑🔑 List 2 Advantages & Disadvantages.

A

Transfemoral Amputation/Above Knee Amputation (AKA)

  • 85% of AKAs are secondary to vascular disease.

Most common level of amputation in the past because:

  • Easily accomplished in cases of PAD
  • Easily assure satisfactory healing.

Disadvantages

  • Hip flexion contracture
    • Up to 20 degrees of flexion can be accommodated in the socket.
  • Hip adduction contracture
    • Use of myodesis of the adductor muscles will help to maintain adduction position of the femur in the prosthetic socket.

Cuccurollo 4th Edition Chapter 6 P&O pg483

36
Q

Components of AKA prosthesis 🔑🔑

A
37
Q

List 2 Design differences between Ischial Containment Socket vs Quadrilateral Socket 🔑🔑

A

Cuccurollo 4th Edition Chapter 6 P&O pg491-492

38
Q

Pros & Cons: Quadrilateral Socket vs Ischial Containment Socket 🔑🔑 EXAM 2018-2019

A

QUADRILATERAL SOCKET

Disadvantages Only

  1. ↑ Discomfort while seated
  2. ↑ Skin irritation at ischium and pubis
  3. Tenderness on anterior distal femur
  4. ↓ Stability (needs hip joint and pelvic band)
  5. More lateral lurch when walking
  6. Poor control of the residual femur, allowing lateral shift of the socket
  7. Poor cosmesis

ISCHIAL CONTAINMENT SOCKET

Advantages

  1. Higher trim line results in better control of the residual limb
  2. Stabilizes the relationship between the pelvis and proximal femur
  3. More energy efficient ambulation at high speed
  4. Narrow ML design is intended to keep the femur in adduction
  5. Able to accommodate smaller residual limb
  6. Greater medial-lateral control of the pelvis
  7. Less lateral thrust
  8. Comfort in groin area

Disadvantages

  1. More expensive
  2. Difficult to fabricate than the quad socket
  3. Wider anterior to posterior dimension at level of ischial ramus leads to increased movement in anterior/posterior plane

Cuccurollo 4th Edition Chapter 6 P&O pg493-492

39
Q

Name, Advantages & Disadvantages

A
  1. Gel liners with a pin or strap
    • Provide suction to the skin and mechanical attachment to the socket
  2. Silesian belt
    • Primary form of suspension or as a supplement if suction is not adequate
    • Enhances the rotational control of the prosthesis
  3. TES belt (total elastic suspension)
    • Comfortable
    • Enhances the rotational control of the prosthesis
  4. Pelvic band and belt with hip joint
    • Enhances the rotational control of the prosthesis
    • Contraindicated in pregnant women

Cuccurollo 4th Edition Chapter 6 P&O pg494

40
Q

Name, Advantages & Disadvantages

A

GEL LINER/SUCTION SUSPENSION

Design

  • One-way valve at the distal end of the socket wall that allows air to escape but not to enter to ensure proper fitting
  • Donning a total suction prosthesis is performed while standing
  1. Total suction socket
    • It provides the best suspension biomechanically
    • Worn without socks on residual limb → Requires minimal volume fluctuation, good hand strength and dexterity, good balance, and good skin integrity.
  2. Partial suction socket
    • Provides less suspension than the total suction socket.
    • Worn with socks, which reduces the suction tightness fit → Requires auxiliary suspension (e.g., Silesian belt or total elastic suspension [TES] belt)

Advantages

  1. Distribute shear forces generated at socket interface
  2. Assists vascular inflow by creating a negative pressure

Disadvantages

  1. Expensive
  2. Not always tolerated
  3. Excessive sweating
  4. Requires stable residual limb volume
    • ↑ size will prevent socket fit
    • ↓ size will result in loss of suction/fit

Cuccurollo 4th Edition Chapter 6 P&O pg493

41
Q

Name (1), Advantages, Disadvantages

A

MANUAL LOCKING KNEE = STRIGHT KNEE UNTIL UNLOCKED IN CHAIR

  • Spring-loaded pin that automatically locks the knee when standing or extending

Uses

  1. K1 ambulator
  2. Blind
  3. Stroke patient with amputation
  4. Last resort

Advantages:

  1. Knee is kept extended throughout the entire gait cycle
  2. Ultimate knee stability in stance phase
  3. Durable
  4. Inexpensive

Disadvantages

  1. No swing phase flexion, resulting in stiff knee gait (locked extension)
  2. Poor gait efficiency
  3. Increased energy consumption
  4. Individual cannot bend both knees at the same time to sit down (sit then unlock)
  5. Awkward in sitting

Cuccurollo 4th Edition Chapter 6 P&O pg494 & 496 Table 6-11

DeLisa 5th Edition Chapter 74 U & LL Prosthetics pg2033 Table 74.5

42
Q

Name (2), Advantages, Disadvantages

A

SINGLE AXIS KNEE UNIT = ↑↓ FRICTION = CADENCE

Design

  • Single Axis With Constant Friction Unit
  • Screw used to adjust the friction to determine how fast or slow the knee swings
  • Constant swing phase control
  • Amputee must prevent knee buckling by activating hip extensors and maintain knee in full extension

Use

  1. K1 ambulator (limited house hold, fixed cadence)
  2. Excellent for pediatrics

Advantages (less parts)

  1. Simple
  2. Low maintenance
  3. Durable
  4. Inexpensive
  5. Light
  6. Reliable
  7. Spring-assisted extension

Disadvantages (advantages of other knee units)

  1. One speed, fixed cadence (based on friction adjustment)
  2. Too much friction prevents knee from flexing
  3. Increased energy expenditure (spring assest is available)
  4. Too little friction causes the knee to swing too easily with high terminal impact
  5. Low stability (early stance)
  6. No stance control

Cuccurollo 4th Edition Chapter 6 P&O pg494 & 496 Table 6-11

DeLisa 5th Edition Chapter 74 U & LL Prosthetics pg2033

43
Q

Name (3), Mechanism of work, Uses, Advantages, Disadvantages

A

WEIGHT ACTIVATED STANCE CONTROL = KNEE CONTROL FROM WEAK HAMS & QUADS

Design

  • Single-axis knee with stance control (Safety Knee/Weight Activated Friction Brake)
  • Stance control acts as a brake system
  • Weight activated = function is activated during weight loading only.
  • Stance control = limit knee buckling during stance, stops flexion at 20 degree ONLY
  • Knee is unlocked on flexing beyond 25 degrees in stance and during swing phase

Uses

  1. K1 ambulator
  2. Geriatrics (weak quads)
  3. General disability (weak hip & knee)
  4. Weak hip extensors (buckling)
  5. Short residual limb (short leverage = weak quads)
  6. Uneven surfaces (high torque on quads)
  7. Slower clients

Advantages

  1. Improved knee stability
  2. Braking mechanism for flexing up to 20 degrees

Disadvantages (now we added feature = more disadvantages for K1 level)

  1. Single cadence
  2. Not very responsive for active walker.
  3. Slightly increased weight
  4. Increased cost
  5. Requires regular maintenance
  6. Must unload fully to flex
    1. Cannot be used in bilateral AKA
    2. Cannot bend both knees at the same time, patient cannot sit down
  7. Hard to use in step-over-step activities as loading is consistent thus will limit the knee motion

Cuccurollo 4th Edition Chapter 6 P&O pg494 Table 6-11

DeLisa 5th Edition Chapter 74 U & LL Prosthetics pg2033 Table 74.5

44
Q

Name (4), Uses, Advantages, Disadvantages

A

FOUR BAR POLYCENTRIC KNEE = BEND & FOLD FOR K2

Uses

  1. K2 > K1 ambulator
  2. Long transfemoral amputee
  3. Knee Disarticulation
  4. Weak hip extensors
  5. Poor stability
  6. Poor balance

Advantages

  1. Excellent knee stability
  2. Short knee unit (used in knee disarticulation and long residual limb)
  3. Shortens shank during swing for better toe clearance
  4. Improved cosmesis

Disadvantages (more features, K2 level)

  1. Increased cost
  2. Maintenance every 3–6 months
  3. Single cadence (K2)
  4. Complex mechanism
  5. Increased weight and bulk

Cuccurollo 4th Edition Chapter 6 P&O pg494 & 496 Table 6-11

DeLisa 5th Edition Chapter 74 U & LL Prosthetics pg2033 Table 74.5

45
Q

Name (5), Mechanism of work, Advantages, Disadvantages

A

PENUMOATIC (AIR) & HYDRUALIC (FLUID) CONTROL

  • Pneumatic units are lighter with swing control only, K2 ambulator
  • Hydraulic units tolerate more weight, but heavier, K3-4 active ambulator
  • Cadence-responsive knee units → Cadence dependent resistance

Uses (K3-4)

  1. K3 and K4 ambulators (Varying Cadence)
  2. Ambulation in uneven terrain
  3. Vary cadence frequency
  4. Active walkers

Advantages

  1. Variable cadence
  2. Smoothest gait
  3. Stable
  4. Can unlock for some activities (e.g., biking)
  5. Can be used for step-over-step manner

Disadvantages (more parts)

  1. Greatest weight
  2. Increased cost
  3. Increased maintenance

Cuccurollo 4th Edition Chapter 6 P&O pg494 & 497 Table 6-11

DeLisa 5th Edition Chapter 74 U & LL Prosthetics pg2033 Table 74.5

46
Q

Name (6), Mechanism of work, Advantages, Disadvantages

A

MICROPROCESSOR CONTROL HYDRAULIC KNEE

  • Programmed knee adjustment based on variable gait cycles: microprocessor recalibrates the stability of the knee 50 times per second to adapt to changing conditions and ultimately prevent falls
  • Not designed to be used for running or other high activity sports.

Advantages

  1. Computer-adjusting knee for variable gait cycles
  2. Energy saving

Disadvantages

  1. Highest cost
  2. Heavy
  3. Increased maintenance
  4. Inconvenience of daily charging
  5. Unproven track record for dependability

Cuccurollo 4th Edition Chapter 6 P&O pg497 TABLE 6-11

47
Q

Hip disarticulation vs Hemipelvectomy. Indication & Major challenge for the patient.

A

Hip disarticulation

Surgical removal of the entire lower limb by transection through the hip joint.

Hemipelvectomy

Surgical removal of the entire lower limb plus all or a major portion of the ileum.

Indications

  1. Malignant tumor
  2. Extensive trauma
  3. Uncontrolled infection
  4. Congenital limb deformity

Challenge

  • Poor mediolateral (ML) trunk stability and marked gait deviations, due to lack of a femoral shaft acting as a lever arm.
  • Bulk and weight of the prosthesis and the high energy expenditure often result in patient rejection of prostheses
  • Lost the excellent weight bearing of the ischial tuberosity (Hemipelvectomy)

Cuccurollo 4th Edition Chapter 6 P&O pg483

48
Q

Name, Main components

A

CANADIAN HIP DISARTICULATION PROSTHESIS

💡 Endoskeletal prosthetic components are preferred for this level of amputation to reduce the overall weight since energy requirement it high.

Components

  1. Socket: encloses the hemipelvis on the side of the amputation and extends around the hemipelvis of the nonamputated side while leaving opening for the nonamputated LE.
  2. Stance-control knee (stable light knee unit)
  3. Single-axis foot or SACH foot (stable light prosthetic foot)

Weight bearing

  • Ischial tuberosity of the amputated side

Indication

  • Amputees with <5 cm of residual femur usually are fitted as hip disarticulation level amputees

Disadvantages

  1. Poor mediolateral (ML) trunk stability
  2. Marked gait deviations

Cuccurollo 4th Edition Chapter 6 P&O pg497-498

49
Q

Supracondylar Socket-where does it bear weight? 🔑

What are the benefits of a transtibial supracondylar suspension prosthesis?

What are the contraindications to the supracondylar suspension system?

A

High medial and lateral sidewalls extending above and over femoral condyles

Advantages

  1. Mediolateral stability
  2. Self-suspending
  3. Easily donned

Contraindications

  1. OBESE patients (unable to grasp femoral condyles due to excess soft tissue)
  2. Large distal thigh CONTOURS (preventing wedge from grasping above femoral epicondyles)
  3. Superficial VASCULAR bypass grafts that run close to the medial femoral condyle

Ref: Braddom p294-5, Delisa p2027

PassPMR - 08 Prosthetics & Orthotics (9 decks)

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