*Orthotics & Biomechanics

Question 1

SACH heel

Answer 1

decreases ground reactive forces at the knee

• solid ankle custom heel
• replaces posterior wedge of the heel (base plantar) w/ compressible foam rubber in order to simulate plantarflexion at heel strike
• A modification made to the heel of a shoe to round off the heel in a rocker-bottom fashion

Question 2

Thomas heel

Answer 2

flares the anteromedial aspect of the standard heel approximately ½ inch to:

• reinforce the longitudinal arch
• limit late midstance pronation
• A reverse Thomas heel is an anterolateral extension made to the heel to support a weak lateral longitudinal arch, rarely indicated.

Question 3

Forefoot Rocker

Answer 3

additional platform on the bottom of the sole that sharply tapers from the metatarsophalangeal joints to the distal end of the shoe

can relieve pressure from the MTPJs by facilitating midstance and toe-off, however does not influence plantarflexion at heel strike

Question 4

External shoe lift

Answer 4

utilized in case of pediatric limb length discrepancy

(as well as haglunds deformity, apophysitis, and equinus)

lift is generally applied to the bottom of the sole in order to accommodate the inequality length

Question 5

Gauntlet Ankle Foot Orthotic

Answer 5

analogous to a pantalar arthrodesis

• restricts and blocks almost all ankle motion
• leather; significantly limits all motion of the hindfoot and midfoot joints

Question 6

Hinged Ankle Foot Orthotic

Answer 6

acts as a subtalar arthroereisis

• allows free ankle motion
• controls and limits subtalar joint motion and midtarsal joint motion

Question 7

if a patient w/ late-stage III flatfoot cannot dorsiflex their ankle to 90°,

and is given a gauntlet AFO in slightly plantarflexed position,

what modification is needed?

Answer 7

heel lift

a heel lift must be incorporated with the accompanying shoe, because without it, the plantarflexed AFO will be poorly tolerated in a shoe

without a heel lift, the front of the brace will apply significant pressure to the anterior aspect of the leg during midstance as tibial attempts to pass over the foot

Question 8

during the contact phase of gait,

position and motion at the level of the pelvis?

Answer 8

0-2 degrees in internal position, and

4-5 degrees internal rotation

Question 9

what is the position and motion during contact phase at:

pelvis, femur, tibia

Answer 9

the motion at the pelvis is minimal to stabilize the trunk over the limb

Question 10

locking mechanism of MTJ is assisted in late stance and propulsive phases as the lesser tarsal bones are stabilized by the synergistic action of the:

Answer 10

posterior tibialis

peroneus longus

peroneus brevis