prosthetics 3

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prosthetics 3
2013-03-10 19:24:07

spring 2013 Holland
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  1. Silesian belt
    • suspension for AKA
    • soft belt going up & over iliac crest (similar to a supracondylar cuff)
    • often used w partial suctioning
  2. partial suction
    • elimiate air btwn stump and socket, creating negative pressure
    • thi'sll have a valve - open it as pt presses in so air can escape, then close
  3. TES - total elastic suspension
    • suspension for AKA
    • belt around pelvis w partial suction
    • (looks like it's a wider, cushier strap than the Silesian belt)
  4. metal hupright hip to band
    • suspension for AKA
    • pelvic band suspension (like thigh corset)
    • big and heavy, but good for people w bad skin & fluctuating stump size
  5. total suction suspension for AKA
    • full reliance on neg pressure
    • (so pt MUST go all the way down in prosthesis when inserting)
  6. what's the tilt (bench alignment) of a BKA socket and why
    • tilted slightly ant 5 degrees
    • helps promote knee flexion during early stance
    • gives better wt distribution on patella tendon --> more normal gait
  7. how to tilt the socket of a BKA if pt has knee flexion contracture?
    normally do 5 degrees ant. now tilt it more ant to accommodate the contracture (this does nothing to correct it)
  8. in BKA, where is prosthetic foot in rel to the center of the socket -- which results in what?
    • slightly post and medial
    • post: the plum line falls slightly ant to the breast of the heel, promoting knee flexion in early stance
    • med: to create normal varus moment at the knee
  9. "breast of heel"
    ant portion of heel
  10. where will the pressure be in a BKA if foot is lateral (it should be a tad post and med of center of socket)
    and leads to what kind of rotation?
    • prox & lat (at knee)
    • distal & med (at stump)

  11. where will the pressure be in a BKA if foot is too medial (it should be a tad post and med of center of socket)
    • prox & med
    • distal & lat
  12. tho for a BKA prosthetic the foot should be a bit med and post for knee flexion & varus, when would you want it less offset from center?
    • shorter resid limb
    • more wt intolerant pt
  13. AKA socket is typically tilted how? why (4 reasons)?
    5 degrees post

    • makes pressure on IT more tolerant
    • helps w post movement of limb in later stances
    • reduces stretch on hip flexors (for people w tight hip flexors allows neutral pos better)
    • slightly lengthens the extensors --> better length tension rel
  14. how to tilt an AKA if pt has a flexion contracture
    more posteriorly (the norm is a bit post)
  15. how does the foot get aligned w AKA
    w center of prosthetic socket
  16. how does the knee get aligned w AKA?
    • a bit post to the plum line (trochanteric-ankle line)
    • to build in extension stability (reduce the impulse to buckle)
  17. where is there a slope in an AKA prosthetic and why?
    • lateral wall slopes inward as it goes inferiorly
    • makes valgus
    • locks femur into add pos, preventing it from going into abd when the glut med activates to hold the opposite hip up
  18. things to consider in a prosthetic check out
    • look at pt
    • sitting
    • standing
    • walking
  19. pistoning
    • prosthesis sliding south during swing
    • shouldn't slide > 1/2 inch
  20. acceptable leg length differences btwn norm & prosthetic, BKA and AKA
    • BKA - no more than 1/4 inch
    • AKA - 1/2 inch, a bit more if it's a locked knee
  21. BKA socket is too far ant tilted --> what gait dev?
    rapid & excessive knee flexion in early stance
  22. what gait dev will you get in a BKA if cushioned heel is too firm
    rapid & excessive knee flexion in early stance (has to do w not getting enough PF

    also seen w flexion contracture and a few other causes
  23. prosthetic foot set too far posteriorly in BKA --> what gait dev?
    rapid & excessive knee flexion in early stance
  24. gait dev in a BKA if weak in quads?
    lack of knee flexion in early stance - pt will avoid flexion and hang on ligs bc  you need more quads to wt bear thru a flexed knee
  25. gait dev in a BKA if pain on ant distal stump??
    lack of knee flexion in early stance (locking relieves pressure)
  26. gait dev in a BKA if socket not tilted enough ant or foot set too far ant?
    lack of knee flexion in early stance
  27. gait dev in a BKA if heel cushion too soft?
    lack of knee flexion in early stance bc the foot goes rapidly into PF
  28. 3 causes of valgus/medial thrusting in BKA
    • foot too lat
    • lax MCL
    • congenital normal alignment
  29. "whip" in gait
    how the heel angles, med or lat, when it rises in swing
  30. reasons for whipping
    • not enough space for hamstring tendons in socket (if not enough space on medial side, foot'll rotate lat to shorten the med tendons)
    • poor fit btwn socket & residual limb
  31. AKA - if the lateral wall isn't adducted enough (slanted in) what gait dev?
    lat flexion ot prostetic side when stepping on that foot bc when glut med tightens to keep the contralat hip level, it raises the resid limb, and since the resid limb is held, instead it shifts the hip towards the limb
  32. some reasons for lat flexing to prosthetic side when stepping on that foot for AKA
    • prosthesis too short
    • weak glut med
    • lat wall not adducted enough
    • med wall is uncomfortable / excessive pressure
  33. reasons AKA will walk w abd prothesis
    • prosthesis too long
    • med wall too high / too much prssure
    • abd contracture (esp for shorter AKAs)
    • pt fear --> widening BOS
  34. too much friction in knee unit of AKA --> what gait dev?
    vaulting or circumduction  --- these can also be due to prostesis too long, pistoning, weak hip flexors, locked knee unit not short enough, pt afraid to flex prosth knee
  35. 3 reasons for ER of AKA on heel strike
    • not compressing/WBing on cushioned heel to get a controlled PF
    • cushion too hard
    • poor socket - prosth rotating on resid limb
  36. AKA 2 reasons for excessive heel rise (presents as knee flexion) in swing?
    • insufficient friction
    • pt flexing too hard
  37. 2 reasons for foot slap in early stance for AKA
    • cushioned heel's too soft
    • pt compressing it too early
  38. AKA w ant tilted pelvis/ increased lumbar lordosis -- why?
    • tight hip flexors
    • socket not tilted enough post
    • pain on IT (ant tilting relieves this pressure)