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Lower Extremity Orthotics - Coggle Diagram
Lower Extremity Orthotics
Static
no moveable joints
block motion
alter pressure around local area
Provides local support
Maintain joint position
Allows patient to change shoes
Ex: solid AFO
Solid
UCBL foot orthotic
support arch and maintain foot alignment
Solid AFO
treat excessive pronation, inversion/eversion
assist in foot clearance
Hold ankle in fixed position
subside for weak PF
subssitutude for weak invertors/evertors
promote ankle & knee stability in stance phase
Supramalleolar orthotic
control alignment of foot while allowing free ankle movement
Posterior Leaf Spring
control PF while allowing DF
support forefoot during swing phase
position foot sagittally at intercostals
Biomechanical Principles
Pressure = Force / Area
Torque = Force x Moment Arm length
Linear Static Equilibrium =
Force = Mass x Acceleration
Rotational Static Equilibrium =
Considerations for fitting orthotic
1) Forces and Moments
2) Tissue Pressure Tolerance
3) Joint Axis Alignment
Dynamic deformity
Can be fixed by passive correction (Deformity caused by over-activation of certain muscle groups)
Fixed deformity
Cannot be fixed with passive correction
External forces: Axial Forces, Shear Forces, Joint moments
Usually in a first class lever system
Dynamic AFO
Articulating (hinged)
Progression through 1st rocker
Controls knee hyperextension in MS w/ PF stop
Control knee flexion in TS
Provides medial lateral stability @ ankle & STJ
Flexible or Posterior Leaf Spring
Positions foot sagittal at IC
Controls PF from IC to LR (1st rocker)
Allows DF (2nd rocker)
Support forefoot during swing phase
Metal single or double upright
Assist swing foot clearance
Assist in transition from IC to LR
Spring loaded DF/PF assist
Dynamic KAFO
Conventional Non-Locking
Offset joint
Single Axis
reduce hyperextension
Control mild-moderate varus
Locking
Single axis drop lock
Variable position lock
control knee buckling
Stance Control (SCKAFO)
control knee buckling
assist with knee extension
