Updated: 6/17/2021

Rehab & Prosthetics

Review Topic
Videos / Pods
  • 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
        • first one crutch is advanced, then the opposite leg, then the second crutch, then the second leg, and so on
      • swing-to
        • that in which the crutches are advanced and the legs are swung to the same point
      • swing-through
        • that in which the crutches are advanced and then the legs are swung past them 
    • 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
      • transfemoral or quadrilateral 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 (medialized)
          • varus strain, circumduction and pain
        • outset foot (lateralized)
          • 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)
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

Double axillary crutch



Single forearm (Lofstrand) crutch



Single axillary crutch



Double cane



Single platform crutch



L 1 C

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(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

Solid ankle ankle-foot orthosis



Hip-knee-ankle-foot orthoses



University of California Biomechanics Laboratory (UCBL) insert



Full-length steel shank shoe modification



Full-length steel shank and rocker sole shoe modification



L 2 C

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(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

Swing-to gait






Swing-through gait



3-point gait



4-point gait



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

Flexes in a controlled manner



Variable cadence



Ability to walk at a moderately fast pace



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



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



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

Provide more proximal function



Better cosmesis



More sensory feedback



Can be used in any position including overhead activities



Require less gross limb movement



L 4 C

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(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

Better for heavy labor activities



Decreased amount of harnessing



Decreased amount of therapy for training



Lighter weight



Less prosthetic maintenance



L 2 C

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(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

Allows variations in cadence



Flexes in a more controlled manner



Lighter in weight



Improved stance control allows less energy expenditure



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



L 2 D

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(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

Traumatic transtibial amputation



Vascular transtibial amputation



Vascular thru-knee amputation



Traumatic transfemoral amputation



Vascular transfemoral amputation



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

Less frequent replacement



Less dorsiflexion



Longer duration midstance of gait



Increased ground reaction forces to the contralateral limb



Diminished maximal gait velocity



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

Single axis foot



Shortened keel nonarticulated dynamic-response foot



Lengthened keel nonarticulated dynamic-response foot



Shortened keel articulated dynamic-response foot



Lengthened keel articulated dynamic-response foot



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

Varus strain



Socket pain located medial and proximal



Increased knee extension during stance



Socket pain located lateral and distal



Circumducted gait



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

Dorsiflex prosthetic foot



Move foot more posterior



Increase flexibility/softness of keel



Move toe break of prosthesis more posterior



Move foot more anterior



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

Low functioning diabetic who needs to transfer bed to chair



Long distance runner with below knee amputation



Elderly male with above knee amputation



Below knee amputee who needs to regularly walk on uneven ground



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



L 1 D

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

QID: 1314

Prosthesis cost



Patient comorbidities



Patient functional status



Patient gender



Patient age



L 2 C

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Evidence (39)
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