Gait - Amputee Pathological

Question 1

Cushioned Heel

Answer 1

• Controls lowering of forefoot to ground during initial contact and weight acceptance (acts as ant tib)
• Too soft cushioned heel — like a weak ant tib causing foot slap (absent knee flexion at heel strike because ankle is in PF with foot slap which causes knee extension)
• Too hard/stiff cushioned heel — like a tight ant tib (aka DF foot, think DF equals knee flexion, and excessive knee flexion at heel strike to midstance, which causes knee buckling and pt will attempt to force knee extension)

Question 2

Extension Aids

Answer 2

• Can be elastic strap, spring, or webbing that assists prosthesis in achieving extension (think of this as a pseudo quadriceps)
• Terminal Swing Impact —> forcible impact as knee goes into extension at end of terminal swing phase just before heel strike (kinda like genu recurvatum in swing phase)
  — Too little friction = causes terminal swing impact because leg swings easily without any friction
  — Too much friction = causes issue where patient cannot get full knee extension in swing
  — Caused by extension aid being set too high (if the extension aid is set too low then it would create an issue where patient cant get full knee extension in swing)

Question 3

Walls

Answer 3

• Plastic thing that goes all way up to pubic area
• High medial wall — patient wants to reduce pressure on pubic ramus resulting in abducted gait, circumduction, or ipsilat lateral trunk lean
• Unsupported lateral wall — patient wants to reach position of optimal support on prosthetic side resulting in abducted gait or ipsilat lateral trunk bending
• Socket too loose / inadequate suspension — like its falling off and youre trying to keep it on, socket is sliding off the leg during the swing phase, resulting in circumduction or pistoning (socket goes up/down on leg due to loose socket)

Question 4

Socket Positions

Answer 4

• Socket flexion = normal is 5-8 degrees
• If excessive, creates knee instability (buckling)
• Insufficient socket flexion, creates knee extension and associated ankle PF

Question 5

Foot Positions

Answer 5

• Anteriorly set foot (or post set socket) — center of gravity line passes anterior to knee but posterior to foot during initial contact to loadin response created an extensor moment (or knee extension)
• Posteriorly set foot — center of gravity line passes post to knee during initial contact to loading response creating a flexor moment or knee flexion (knee buckling)

Question 6

Pressure Sensitive Areas

Answer 6

• Patella
• Lateral tibial condyle
• Tibial tuberosity
• Tibial crest
• Anterior distal end of tibia
• Fibular head
• Distal end of fibula
• Distal end of stump with surgical suture
• Medial and lateral femoral condyles

Question 7

Pressure Tolerant Areas

Answer 7

• Supracondular areas
• Suprapatellar area
• Patellar tendon
• Medial and lateral flare of tibia
• Lateral flare of fibula
• Posterior area of stump
• Popliteal area (gently)
• Distal end of stump for total contact socket (no pressure, contact only)