Management of Ankle Mortise

SMO - supramalleolar orthoses

UCBL with “wings”

shortest AFO

pets and adult applications

supports 3 arches of foot

more hind foot control than FO

articulated vs non-articulated

indications for SMO

flexibly deformity

hypotonia

subtalar instability

severe pronation/supination

development delay

poor coordination or balance

contraindications for SMO

rigid deformity

knee instability

extreme tow walking

spasticity

hypertonia

tight heel cord

trimlines for SMO

proximal to malleoli

contain navicular

posterior contain calcaneus

bisect 1st and 5th met heads

some have unique trimlines

• 1st met head free

• 5th met head contained

• extensions for ad/abduction

biomechanics of SMO

• 3pt forces to control varus/valgus or other deformity

• strap increases force on anterior tibia exponentially the closer to ankle joint

• forces on foot/ankle sometimes not tolerated by adults (unless articulated)

• strap placement can cue gait training

rocker implications for SMO

PF/DF free minimal impact

crawling/cruising possible

in combo (articulating)

can be used as inner shell part of larger AFO

improved med-lat control in AFO

more contact = improved pressure distribution

lace-up gauntlet “Arizona”

custom polypro encased in leather with lace closure

immobilization in all 3 planes

stabilizes subtalar, mid tarsal, talocalcaneal joints

indicated for PTTD, DJD, ankle instability, severe varus/valgus

biomechanics of SMO

standard trimlines - 5 in above malleoli, pros to met heads

goal of lower trimlines to allow some motion for gait