DPT875: Prosthetics

what are common causes of amputation

-diabetic complications
-PVD
-trauma (MVA, GSW, severe burns)
-congenital
-malignancy (osteosarcomas)

define tarsometatarsal (lifranc) amputation

amputation through tarsometatarsal joint

What amputation attaches heel pad to distal end of tibia; may include removal of malleoli & distal tibial/fibular flares (removal of entire foot except calcaneal fat pad)

ankle disarticulation (syme's) amputation

define transtibial (below knee) amputation

between 20% & 50% of tibial length

define knee disarticulation amputation

amputation through knee joint; femur intact

define transfemoral (above knee) amputation

between 35% & 60% of femoral length

define hip disarticulation amputation

amputation through hip joint; pelvis intact

What is a resection of part of the pelvis?

hemipelvectomy

What is an amputation of both lower limbs & pelvis below L4-L5 level?

hemicorporectomy

What are the techniques used for stabilization of major muscle during surgery to allow for retention of muscle tension & max muscle function & describe them

-myofascial closure: muscle to fascia
-myoplasty: muscle to muscle
-myodesis: muscle attached to periosteum or bone
-tenodesis: tendon attached to bone

what surgical technique is often used in transtibial amputation?

posterior skin flaps often used in transtibial amputations w/ compromised circulation because posterior tissues have better blood supply than anterior skin

what surgical incision type is often used in transfemoral amputation?

knee mouth incisions/skew flap which is angled M-L so that scar is placed away from bony prominences

describe the technique used to prevent neuromas (ball of nerves in residual limb)

major nerves are identified, pulled down under tension, & cut

describe the goals of phase 1 (pre-op) for therapy (5)

-Strengthening sound limb
-Maintaining UE strength
-Practicing single-limb activities
-Stretching joints around amputation site
-Education on phases to come

when does phase 2 (post-op) of therapy usually start, where does it occur, & how long does it last?

-time b/t surgery & discharge of acute care
-occurs in acute care setting
-usually lasts 3-5 days

what are the goals of phase 2 of therapy?

-Promote residual limb wound healing
-Residual limb pain mgmt & control phantom limb pain/sensation
-Optimize strength of both LE & UE
-Protect remaining limbs
-Demo functional sitting & standing balance
-Perform independent transfers & bed mobility
-Ambulate w/ appropriate AD
-Demo proper sitting & bed positioning
-Begin psychological adj
-Understand process of prosthetic rehab

what must be documented if trying to justify that a pt is suitable for IP rehab during phase 2 of therapy (post-op amputation)?

must show that pt can tolerate 3 hrs of therapy if trying for IP rehab

what is the most common type of contracture that develops in transtibial amputations & transfemoral amputations?

-transtibial: knee flexion contracture
-transfemoral: hip flexion & hip ABD contractures

what positioning precautions should be taken to avoid transtibial or transfemoral contractures in phase 2?

-spend at least 30 mins in prone position each day
-AVOID placing pillow under RL when in supine & prolonged sitting

define an immediate post-op prosthesis (IPOP) that is used in phase 2 of therapy

-applied directly in surgery or in following next days
-can be custom or off the shelf
-allows pt to walk following days after surgery
-for pt's who are able to heal good (DM & PVD pt's likely will not use this)

describe a stump protector used in phase 2 of therapy

-post-op protection of residual limb that reduces risk & incidence of wound trauma
-provides compression & edema control
-able to be put on top of ACE or shrinker → protective brace esp w/ falls
-typically used for transtibial & transfemoral

describe a shrinker commonly used in phase 2 of therapy

-reduces & controls edema, helps form limb for prosthesis
-compression sock pt can wear instead of ACE wrap
-takes conservative time for surgeon to clear pt to have this
-easier to maintain & donn compared to ACE
-worn for at least 1 yr when not wearing their leg
-should wear at night for about a 1-2 yrs to help residual limb get to shape it needs
-not used until incision is healed & sutures removed

when does phase 3 (pre-prosthetic training) of therapy usually start, where does it occur, & how long does it last

-usually starts 1-2 months after surgery
-occurs in IP rehab, SNF, or OP (outcomes better if in IP)
-typically lasts 7-14 days

describe the focus of phase 3 pre-prosthetic training

-Desensitization → continue w/ limb forming/shrinking (shrinkers)
-CV endurance
-Maintaining jt mobility, scar mobs
-Strengthening, balance/coordination
-Continuing w/ ambulation & WC mobility,
-Stair training, floor transfers, self-care/ADLs, cognitive function, IADLs (goal is to amb household distances if appropriate)

list outcome measures commonly used in phase 3 (7)

-AmpNoPro
-SLS
-TUG
-Ottawa sitting scale
-Functional reach test
-Mini-cog
-MOCA

when does phase 4 (prosthetic training) of therapy usually start, where does it occur, & how long does it last

-usually starts 2-6 months after surgery
-occurs in IP rehab &/or OP
-lasts 7-14 days IP/SNF or 8-12 wks OP

what is the focus of phase 4 of therapy

-Don/doff prosthesis
-Wear schedule
-Liner/sock mgmt
-Prosthetic WBing
-Learning how to lock/unlock prosthetic knee
-Normal pelvic & trunk motion
-Gait training, stairs, outside

define K0 (functional level 0)

non-ambulator

define K1 (functional level 1)

household ambulator

define K2 (functional level 2)

limited community ambulator (able to do low level environmental barriers such as curbs)

define K3 (functional level 3)

community ambulator w/ ability to walk various speeds/show variable cadence (biggest difference b/t K2 & K3**)

define K4 (functional level 4)

active adult, athlete, child

list the scores of the AMPPro as they correlate to each K level (K0-K4)

K0 = 0-8
K1 = 9-20
K2 = 21-28
K3 = 29-36
K4 = 37-43

what score on the TUG indicates increased risk for falls at 6 months post-d/c

>/= 19 seconds

what scores on the Houghton indicate K1 level, K2 level, and K3/K4 levels

-K1: <= 5
-K2: 6-8
-K3/K4: >= 9

what score on the 2MWT indicates K3/K4 level

>= 113 meters

what gait speed is predictive of prosthesis non-use at 1 year post-d/c

<= 0.44 m/s

describe phase 5 (long term follow up) of therapy post-amputation

-Every 3-5 yrs may get new prosthesis
-Pending on changes may need therapy again
-May need adj to socket, additional socks/liners, or additional care w/ 2ndary conditions
-Should be getting new liners every 6 months
-Sockets are fit based

what foot prosthetic stimulates the shape of missing foot segment to restore as much foot function as possible (w/ walking) via shoe inserts/fillers?

-can have arch support or convex rocker bar to assist w/ stance

partial foot prosthetic

what components make up a transtibial prosthesis (below knee)

-foot-ankle assembly
-a shank (lower limb)
-socket
-suspension system

what components make up a transfemoral prosthesis (above knee)

-foot-ankle assembly
-a shank (lower limb)
-knee unit
-socket
-suspension system

what components make up a hip disarticulation prosthesis

-foot-ankle assembly
-a shank (lower limb)
-hip unit
-knee unit
-socket
-suspension system

What is a non-articulated (no joint b/t foot & shank), lightweight, basic foot/ankle prosthetic option optimal for light activity? (like a wood block)

solid ankle cushion heel (SACH)

What foot/ankle prosthetic stores energy thru early & midstance & then releases energy during late stance via carbon fiber material?

-these structures return to their original shape at end of each step, resulting in a return of stored energy as well as a more natural, fluid gait

-nonarticulated

dynamic response feet

What articulated foot component that only allows for DF/PF at ankle via posterior bumpers (resists PF) & anterior bumper (resists DF)

single-axial feet

What articulated foot component that allows movement in all planes? (M-L, A-P)

multi-axial feet

What foot/ankle prosthetic allows resisted mvmt of prosthetic foot at an adjustable hydraulic ankle jt?

-increases stability to walking on uneven terrain

hydraulic ankle feet

What foot/ankle prosthetic can change resistance of prosthetic ankle in real time based on walking speed, incline/decline of a slope, & type of terrain?

microprocessor feet

What ankle/foot prosthetic utilizes battery power propulsion of foot & ankle muscles?

powered feet

describe the 2 common transtibial socket types

-patellar tendon bearing (PTB): WBing occurs on patellar tendon
-total surface bearing: WBing occurs on whole socket

describe the 2 common transfemoral socket types

-quadrilateral: provides more stability by having anterior, posterior, medial, & lateral walls
-ischial containment socket: sits on ischium allowing for more hip mvmt (good for active patients or short RLs but does not provide as much stability as quad)

what are 2 types of hip disarticulation sockets

canadian and bikini

describe the levels of ply (fabric socks women in various thicknesses, designating # of threads knitted together)

1 = thinnest, 3, 5 = thickest

what gait deviations may occur if a pt is wearing too many (or too little) socks on their prosthetic limb (5)

-limb may appear too short or too long
-pivoting or twisting in prosthesis
-antalgic gait due to ℅ increased pain distally in limb, in front of knee, or in groin
-increased M/L mvmt
-foot catching during swing

What part of transfemoral prosthesis is simplest mechanical stabilizer?

-wearer must manipulate an unlocking lever to allow for knee flexion

-locked knee provides more stabilization

-typically indicated for K1 or individuals who can not control their prosthesis or buckle

-helps w/ transfers & limited ambulation

manual lock knee unit for transfemoral prosthesis

describe a non-microprocessor (polycentric) versus a microprocessor knee unit for transfemoral prosthesis

-non-microprocessor: 4 or more pivoting bars to provide great knee stability but is complex
-microprocessor: utilize electronic sensory which detect rate & range of shank mvmt providing instant friction adj to change gait based on different terrain

What knee unit for transfemoral prosthesis is very common?

-weight activated stance control

-knee locks w/ WBing thru heel

-knee unlocks w/ WBing thru forefoot

stance control (monocentric & pneumatic) knee unit for transfemoral prosthesis

what is the focus of gait training with a prosthetic

-prosthetic WBing
-increasing step length on sound side
-decreasing step length on prosthetic side
-increasing speed overall (1.3 m/s = typical gait speed)
-decreasing speed of sound side swing
-increasing speed on prosthetic side swing
-proper knee flexion on prosthetic side during swing
-achieving terminal hip extension
-pelvic rotation
-arm swing

describe the common gait deviation in prosthetics, vaulting, its causes & how to reduce it

-w/ sound side to clear prosthetic side due to inadequate knee flexion on prosthetic side or potentially prosthesis too long
-can help to reduce by attempting to maintain DF on sound limb during gait cycle

describe the causes of circumduction/ABD when wearing a prosthesis & how to reduce it

-lack of confidence in flexing knee/poor gait training causing avoidance of knee flexion, prosthesis too long, knee component friction too much/knee flexion resistance too high, medial brim of socket impingement (pt avoids rubbing by circumducting)
-use mirror so pt can see, give cues to bring prosthetic side medially & sound limb laterally

describe the cause of trendelenberg and how to reduce it when wearing a prosthesis

-weak ABD musculature
-work on keeping socket tight to their hip w/ exercises

What are the causes of increased BOS or too narrow of BOS when wearing a prosthesis?

-wide BOS: having sound limb too close to midline, increase balance, prosthesis being set out too far laterally
-narrow BOS: seen in turning or pivoting BOS becomes too narrow due to not knowing where the residual limb is in space

describe the causes of decreased step length when wearing a prosthesis & what you will typically see due to the decreased step length

-typically on sound side, decreased tolerance for WBing on prosthetic side due to pain &/or weakness
-will see decreased stance & increased swing on prosthetic side
-will see rapid unloading of prosthesis & early loading of sound side

What causes of toeing in when wearing a prosthesis?

on prosthetic side, w/ TF socket on wrong or too loose (tighten down strap), gait too slow & pt not controlling prosthetic side well

what are the causes of decreased knee flexion in both TT & TF during swing?

due to weakness or excessive socks

describe why you would see decreased knee extension in stance in both TT & TF

-TT: due to weakness as well or tightness in musculature (contracture) will complain of pain in distal tibia when walking on a bent knee
-TF: will see an unstable knee, due to weakness in hip extensors, need to push residual limb back into socket more

at initial contact, what would be the causes of excessive knee extension (3)

-faulty suspension
-insufficiency pre-flexion of socket
-foot too anterior/too far forward (shifts GFR anteriorly to knee jt forcing it back)

at IC/early stance, what would be the causes of excessive knee flexion (7)

-faulty suspension
-flexion contracture
-weak quads
-socket too anterior
-socket excessively flexed
-shoe heel too high
-insufficient PF

at IC, what would be the cause of unequal stride lengths (smaller steps)

-foot too posterior/anterior
-poor balance/inadequate gait training

at IC, what would be the cause of foot ER (foot turns out at IC)

-heel too firm/rigid = forces not absorbed by heel
-poor socket fit in popliteal region

at LR, what would be the cause of crushing the heel (knee remains extended & pt rides on heel) (4)

-Foot too anterior
-Socket too extended, foot to PF (due to GFR anterior)
-Prosthetic foot heel too soft (squishy heel instead of ankle rocker)
-Heel on shoe too low

what would be the cause of knee instability causing abrupt knee flexion (5)

-Weak quads
-Foot too posterior
-Socket too flexed, foot too DF
-Heel on shoe too stiff or too high
-Prosthetic foot bumper or heel wedge too firm

at LR, what would cause foot slap?

-PF resistance too soft
-Incorrect foot category (weight gain)

in the frontal plane, what would cause the pylon to lean too medially or lean too laterally (2)

-pylon leaned medially: too much socket ADD or foot too outset
-pylon leaned laterally: socket too neutral (more ABD) or foot too inset

in the frontal plane, what would cause excessive varus or excessive valgus

-excess varus: foot too inset medially (GFR more towards midline → causing knee to force out)
-excess valgus: foot too outset laterally (GFR more lateral - force knee inward towards middle)

in the frontal plane, what would cause an ABD gait?

-Prosthesis too long
-Transfemoral socket pressure on ramus

in the sagittal plane, what would cause early heel off/late knee buckle at terminal stance (knee buckles/flexes quickly)

-Foot too posterior (causing GFR to go too posterior)
-Foot too DF

in the sagittal plane, would would cause delayed heel off & possible hyperextension at terminal stance?

-Foot too anterior (causing GFR to go too anterior)
-Foot too PF

in the sagittal plane, what would cause pistoning & how should a PT fix this

-loose suspension
-fix this by adding more socks

in the sagittal plane, what would cause early heel rise at terminal stance/pre-swing?

inadequate knee flexion resistance (need more stiffness so knee is not flexing too early)

in swing, what would cause the foot to WHIP medially or laterally

socket rotated either medially or laterally

in swing, what would cause the prosthetic to hit the ground/toe drag (4)

-Prosthesis too long
-Suspension loose
-Knee flexion limited
-Muscle weakness

in swing, what would cause fast/agressive hyper extension at the end of swing (terminal impact)

inadequate knee joint resistance