Updated: 6/17/2021

Rehab & Prosthetics

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  • Introduction
    • The goal of prosthetics are to restore limb function to as close to original function
    • Requires a multidisciplinary team approach for coorindation of efforts to achieve the best outcome
    • Prosthetics
      • upper limb
        • limb salvage is ideal in the upper arm given lack of sensation with prosthetic
        • residual limb length is important for suspending prosthetic socket
      • lower limb
        • goals for prosthetic are comfort, easy to get on and off, light, durable, cosmetic, and functional
  • Gait
    • Antalgic gait describes any gait abnormality resulting from pain
      • shortened stance phase on the affected limb
    • Gait pattern of ambulation with an assistive device
      • 3-point
        • both the crutch and the injured limb move forward together with weight-bearing on the crutches followed by all of the weight on the uninjured limb
      • 4-point
      • swing-to
      • swing-through
    • Crutch walking
      • requires more energy than walking with a prosthesis
      • muscles that need strengthening in preparation for crutch walking
        • latissimus dorsi
        • triceps and biceps
        • quads
        • hip extensors
        • hip abductors
    • Wheelchair propulsion
      • 9% increase in energy expenditure compared to ambulation in normal subjects
    • Ambulation assistive devices
      • cane
        • shifts center of gravity towards affected side when cane is used on contralateral side
      • axillary crutch
        • 2 axillary crutches are required for proper gait if lower extremity is non weight-bearing or toe-touch weight-bearing
  • Upper Extremity Prostheses
    • Timing of prosthetic fitting
      • as soon as possible, even before complete wound healing has completed
        • better outcomes if fitted within 30 days
    • Midlength transradial amputation
      • Myoelectric prostheses
        • best candidate is a patient with a midlength transradial amputation
        • transmits electrical activity to surface electrodes on residual limb muscles
        • advantages
          • better cosmesis
          • allows more proximal coverage
        • disadvantages
          • heavier and more expensive prosthesis
          • requires more maintenance
      • Body-powered prostheses
        • indications
          • best for heavy labor with less maintenance needed
        • techniques
          • activate terminal device with shoulder flexion and abduction
          • center the harness ring just off the midline of C7 towards the non-amputated side
        • advantages
          • moderate cost and weight
          • most durable prosthesis
          • higher sensory feedback
        • disadvantages
          • poorer cosmesis
          • requires more gross upper limb movement for proper function
    • Elbow disarticulation or above elbow amputation
      • requires a prosthesis to recreate functional motion of two joints (elbow and wrist)
        • this creates heavy and less efficient as the only solution
        • best function with least weight is achieved by combining the various options of myoelectric, body-powered, and body-driven switch components
    • Proximal transhumeral and shoulder disarticulation amputation
      • an amputation this proximal has lost the ability to create a lever arm with mechanical advantage
      • best option is a universal shoulder joint that is positioned in space with the contralateral arm
      • this can be combined with lightweight hybrid prosthetic components
    • Components
      • Terminal device
        • passive terminal device
          • more cosmetic but less functional than active terminal devices
        • active terminal device
          • more functional, but less cosmetic than passive terminal devices
          • either hooks and prosthetic hands with cables or myoelectric devices
        • grips
          • precision grip (pincer-type)
          • tripod grip (palmar grip, 3-jaw chuck pinch)
          • lateral pinch (key pinch)
          • hook power grip
          • spherical grip
        • prehension devices
          • handlike device
            • thumb, index, and long finger components
            • may be covered with a glove for better cosmesis
            • good choice for office worker
          • non-hand prehension device
            • hook or two-finger pincer with parallel surfaces
            • may attach task-specific tools with quick release mechanism
            • good for physical labor
          • myoelectric devices
            • can only be used in an environment clean from dirt, dust, water, grease, or solvents
        • mechanisms
          • voluntary opening
            • device is closed at rest and opens with contraction of proximal muscles
            • more common than voluntary closing
          • voluntary closing
            • device is open at rest and residual forearm flexors grip the desired object
            • heavier and less durable than voluntary opening
      • wrist units
        • quick disconnect wrist
          • allows easy swapping of devices with specialized function
        • locking wrist unit
          • prevents rotation during grasping and lifting
        • wrist flexion unit
          • used in bilateral upper extremity amputees
          • placed on longer residual limb to allow midline activities (shaving, buttoning)
      • elbow units
        • rigid elbow hinge
          • indications
            • short trans-radial amputation with inability to pronate or supinate with maintenance of elbow flexion
        • flexible elbow hinge
          • indications
            • wrist disarticulation or long transradial amputation with sufficient pronation, supination, and elbow flexion and extension
      • shoulder units
        • due to increased energy expenditure and weight of prosthesis many choose to use a purely cosmetic prosthesis
        • indications
          • forequarter or shoulder level amputation
  • Lower Limb Prosthesis
    • Foot prosthesis
      • Single axis foot
        • ankle hinge allows dorsiflexion and plantar flexion
        • disadvantages
          • poor durability and cosmesis
      • SACH (solid ankle cushioned heel) foot
        • indications
          • general use in patients with low activity levels
          • use is being phased out
        • disadvantages
          • overloads the nonamputated foot
      • Dynamic response (energy-storing) foot
        • indications
          • general use for most normal activities
          • patients who regularly ambulate over uneven surfaces likely benefit from multi-axial articulated prostheses
        • articulating and non-articulating dynamic-response foot prostheses are available
          • articulating
            • allows inversion, eversion, and rotation of the foot
            • indications
              • patients walking on uneven surfaces
            • advantages
              • allows inversion, eversion, and foot rotation
              • absorbs loads and decreases shear forces
              • flexible keels
                • acts as a spring to decrease contralateral loading, allow dorsiflexion, and provide a spring-like push-off
                • posterior projection from keel gives a smooth transition from heel-strike
                • sagittal split allows for inversion and eversion
          • non-articulating
            • have short or long keels
              • shorter keels are not as responsive and are indicated for moderate-activity patients
              • longer keels are indicated for high-demand patients
            • different feet for running and lower-demand activities available
      • Shanks
        • provide structural support between components
        • endoskeleton (soft exterior) or exoskeleton model (hard exterior)
        • can provide a lever arm for propulsion following transmetatarsal amputation
    • Knee prosethesis
      • Indications
        • transfemoral and knee disarticulation amputations
        • patient functional status is an important consideration
      • Six types of prostheses for AKA or through knee
        • polycentric (four-bar linkage) knee
          • indications
            • transfemoral amputation
            • knee disarticulations
            • bilateral amputations
          • techniques
            • variable knee center of rotation
            • controlled flexion
            • ability to walk at a moderately fast pace
            • supports increased weight compared to constant friction knee
        • stance-phase control (weight-activated) knee
          • indications
            • older patients with proximal amputations
            • patients walking on uneven terrain
          • techniques
            • acts like a constant-friction knee in swing phase
            • weightbearing through the prosthesis locks up through the high-friction housing
        • fluid-control (hydraulic and pneumatic) knee
          • indications
            • active patients willing to sacrifice a heavier prosthesis for more utility and variability
          • techniques
            • allows for variable cadence via a piston mechanism
            • prevents excess flexion
            • extends earlier in the gait cycle
        • constant friction (single axis) knee
          • indications
            • general use
            • patients walking on uneven terrain
            • most common pediatric prosthesis
            • not recommended for older or weaker patients
          • technique
            • hinge that uses a screw or rubber pad to apply friction to the knee to decrease knee swing
            • only allows a single speed of walking
            • relies on alignment for stance phase stability
        • variable-friction (cadence control)
          • technique
            • multiple friction pads increase knee flexion resistance as the knee extends
            • variable walking speeds are allowed
            • not very durable
        • manual locking knee
          • technique
            • constant friction knee hinge with an extension lock
            • extension lock can be unlocked to allow knee to act like a constant-friction knee
    • Socket
      • the connection between the stump and the prosthesis
      • computer screening technology can decrease time to socket fabrication
      • preparatory socket may need to be adjusted several times as edema resolves
      • patellar tendon-bearing prosthesis is most common for BKA
      • transfermoral or quadilateral sockets make it hard to keep the femur in adduction
        • transfemoral allow 10 degrees of adduction and 5 degrees of flexion
    • Suspension systems
      • attaches prosthesis to residual limb using belts, wedges, straps, and suction
      • suction suspension
        • standard suction
          • form-fitting rigid or semi-rigid socket which fits onto residual limb
        • silicon suction
          • silicon-based sock fits over the stump and is then inserted into the socket
          • silicon provides an airtight seal between prosthesis and amputated stump
    • Pylon
      • simple tube or shell that attaches the socket to the terminal device
      • newer styles allow axial rotation and absorb, store, and release energy
      • exoskeleton
        • soft foam contoured to match other limb with hard outer shell
      • endoskeleton
        • internal metal frame with cosmetic soft covering
    • Osseointegration
      • direct attachment of a prosthesis to the skeleton
      • may improve biomechanical advantage of prosthesis and rehabiliation
    • Terminal device
      • Most commonly a foot, but may take other forms
  • Prosthetic Complications
    • General issues
      • choke syndrome
        • caused by obstructed venous outflow due to a socket that is too snug
        • acute phase
          • red, indurated skin with orange-peel appearance
        • chronic phase
          • hemosiderin deposits and venous stasis ulcers
      • skin problems
        • contact dermatitis
          • most commonly caused by liner, socks, and suspension mechanism
          • treatment
            • remove the offending item with symptomatic treatment
        • cysts and excess sweating
          • signs of excess shear forces and improperly fitted components
        • scar
          • massage and lubricate the scar for a well-healed incision
      • painful residual limb
        • possible causes include heterotopic ossification, bony prominences, poorly fitting prostheses, neuroma formation, and insufficient soft tissue coverage
    • Transtibial prostheses
      • swing-phase pistoning
        • ineffective suspension system
      • stance-phase pistoning
        • poor socket fit
        • stump volume changes (stump sock may need to be changed)
      • foot alignment abnormalities
        • inset foot
          • varus strain, circumduction and pain
        • outset foot
          • valgus strain, broad-based gait and pain
        • anterior foot placement
          • stable increased knee extension with patellar pain
        • posterior foot placement
          • unstable increased knee flexion
          • drop-off or knee buckling can be improved by moving the foot more anterior
        • dorsiflexed foot
          • increased patellar pressure
        • plantar-flexed foot
          • drop-off and increased patellar pressure
      • pain or redness related to pressure
      • prosthetic foot abnormalities
        • heel is too soft
          • leads to excessive knee extension
        • heel is too hard
          • leads to excessive knee flexion and lateral rotation of toes
Flashcards (8)
Cards
1 of 8
Questions (14)

(OBQ11.174) A 34-year-old female undergoes open reduction and internal fixation (ORIF) for the left lower extremity injury shown in Figures A-C. Her postoperative weight bearing protocol includes touch down weight bearing to the left lower extremity. Which of the following ambulatory support devices is most appropriate for this patient?

QID: 3597
FIGURES:
1

Double axillary crutch

93%

(2844/3047)

2

Single forearm (Lofstrand) crutch

1%

(45/3047)

3

Single axillary crutch

3%

(99/3047)

4

Double cane

1%

(20/3047)

5

Single platform crutch

1%

(24/3047)

L 1 C

Select Answer to see Preferred Response

(OBQ11.177) A 32-year-old man has difficulty walking 5 months after having an amputation as shown in Figure A. Gait analysis reveals a shortened stance phase and irregular toe off on the operative extremity. Which of the following would most likely improve his ambulation?

QID: 3600
FIGURES:
1

Solid ankle ankle-foot orthosis

7%

(265/3676)

2

Hip-knee-ankle-foot orthoses

1%

(29/3676)

3

University of California Biomechanics Laboratory (UCBL) insert

4%

(152/3676)

4

Full-length steel shank shoe modification

11%

(388/3676)

5

Full-length steel shank and rocker sole shoe modification

76%

(2811/3676)

L 2 C

Select Answer to see Preferred Response

(OBQ11.41) The pattern of ambulation shown with the assistive device in Video A is most appropriately described as which of the following?

QID: 3464
FIGURES:
1

Swing-to gait

56%

(1515/2729)

2

Drag-to-gait

1%

(37/2729)

3

Swing-through gait

31%

(854/2729)

4

3-point gait

5%

(140/2729)

5

4-point gait

6%

(158/2729)

L 4 C

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(OBQ10.245) A prosthetic polycentric knee with hydraulic swing control is chosen for a very active 63-year-old transfemoral amputee. All of the following appropriately describe the features of this prosthesis EXCEPT:

QID: 3344
1

Flexes in a controlled manner

4%

(117/3062)

2

Variable cadence

8%

(256/3062)

3

Ability to walk at a moderately fast pace

5%

(148/3062)

4

Knee center of rotation is fixed anterior to the line of weight bearing

68%

(2086/3062)

5

Weighs more than a constant friction knee that has a manual extension locking mechanism

14%

(420/3062)

L 2 C

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(OBQ10.195) Patients with transradial amputations are considered the best candidates for a myoelectric prosthesis. Each of the following are advantages of a myoelectric device compared to a body controlled device EXCEPT:

QID: 3287
1

Provide more proximal function

20%

(630/3146)

2

Better cosmesis

11%

(347/3146)

3

More sensory feedback

54%

(1701/3146)

4

Can be used in any position including overhead activities

9%

(274/3146)

5

Require less gross limb movement

5%

(172/3146)

L 4 C

Select Answer to see Preferred Response

(OBQ10.128) All of the following are advantages of a body-controlled prosthesis compared to a myoelectric prosthesis for patients with upper extremity amputations EXCEPT:

QID: 3221
1

Better for heavy labor activities

8%

(254/3207)

2

Decreased amount of harnessing

67%

(2156/3207)

3

Decreased amount of therapy for training

10%

(334/3207)

4

Lighter weight

11%

(347/3207)

5

Less prosthetic maintenance

3%

(94/3207)

L 2 C

Select Answer to see Preferred Response

(OBQ09.267) In consideration of a prosthetic knee, each of the following are advantages of choosing a polycentric knee with fluid control over a constant friction knee EXCEPT:

QID: 3080
1

Allows variations in cadence

5%

(76/1415)

2

Flexes in a more controlled manner

10%

(145/1415)

3

Lighter in weight

62%

(873/1415)

4

Improved stance control allows less energy expenditure

11%

(151/1415)

5

Overall length of the limb is shortened during initiation of a step reducing the risk of stumbling

11%

(154/1415)

L 2 D

Select Answer to see Preferred Response

(OBQ08.146) Which of the following amputations has the LEAST increase in metabolic demand for walking compared to a healthy patient without amputation?

QID: 532
1

Traumatic transtibial amputation

77%

(2315/2991)

2

Vascular transtibial amputation

19%

(558/2991)

3

Vascular thru-knee amputation

1%

(38/2991)

4

Traumatic transfemoral amputation

1%

(23/2991)

5

Vascular transfemoral amputation

1%

(40/2991)

L 2 C

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(OBQ08.266) A 45-year-old patient with a below knee amputation is interested in hiking as a hobby. He would like to know more about his SACH foot before selecting a different terminal device. A SACH foot or non-dynamic response (non-energy storing) foot, as compared to the dynamic response foot (energy storing) demonstrates all of the the following EXCEPT:

QID: 652
1

Less frequent replacement

13%

(156/1219)

2

Less dorsiflexion

9%

(104/1219)

3

Longer duration midstance of gait

41%

(495/1219)

4

Increased ground reaction forces to the contralateral limb

27%

(335/1219)

5

Diminished maximal gait velocity

10%

(118/1219)

L 4 C

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(OBQ06.254) A 44-year-old male with transtibial amputation is interested in doing more hiking as a hobby, however he has had difficulty negotiating uneven terrain with a solid-ankle, cushioned-heel (SACH) prosthetic foot. Which of the following modifications to the new prosthesis is most appropriate?

QID: 265
1

Single axis foot

1%

(11/1410)

2

Shortened keel nonarticulated dynamic-response foot

20%

(277/1410)

3

Lengthened keel nonarticulated dynamic-response foot

13%

(188/1410)

4

Shortened keel articulated dynamic-response foot

60%

(848/1410)

5

Lengthened keel articulated dynamic-response foot

5%

(72/1410)

L 3 D

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(OBQ06.12) A 27-year-old patient comes in for a new prescription for his below knee amputation prosthesis because it is not fitting properly. All of the following are complaints and examination findings consistent with a prosthetic foot that is placed too far inset EXCEPT:

QID: 23
1

Varus strain

3%

(72/2349)

2

Socket pain located medial and proximal

19%

(455/2349)

3

Increased knee extension during stance

34%

(795/2349)

4

Socket pain located lateral and distal

35%

(813/2349)

5

Circumducted gait

8%

(192/2349)

L 4 D

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(OBQ06.101) A 35-year-old woman with a transtibial prosthesis is seen to have knee buckling (i.e "drop-off") during terminal stance. What prosthetic modification would correct this problem?





QID: 287
1

Dorsiflex prosthetic foot

7%

(150/2025)

2

Move foot more posterior

24%

(481/2025)

3

Increase flexibility/softness of keel

2%

(48/2025)

4

Move toe break of prosthesis more posterior

6%

(119/2025)

5

Move foot more anterior

59%

(1202/2025)

L 3 D

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(OBQ05.243) A prosthetic foot which incorporates a multi-axis articulated foot assembly is recommended for which of the following amputees?

QID: 1129
1

Low functioning diabetic who needs to transfer bed to chair

0%

(1/1329)

2

Long distance runner with below knee amputation

10%

(134/1329)

3

Elderly male with above knee amputation

1%

(12/1329)

4

Below knee amputee who needs to regularly walk on uneven ground

85%

(1135/1329)

5

10-year-old male with above knee amputation from osteosarcoma

3%

(38/1329)

L 1 D

Select Answer to see Preferred Response

(OBQ04.209) What is the most important factor when choosing an optimal lower limb prosthesis for an adult patient?

QID: 1314
1

Prosthesis cost

0%

(5/1923)

2

Patient comorbidities

1%

(17/1923)

3

Patient functional status

95%

(1818/1923)

4

Patient gender

3%

(65/1923)

5

Patient age

1%

(14/1923)

L 2 C

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EXPERT COMMENTS (14)
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