Updated: 8/12/2019


Review Topic
  • About  
    • play an important role in nonoperative treatment of foot and ankle pathology
    • provide soft tissue protection, bone/joint stability and control of body segment motion
  • Uses
    • off-load areas of high pressure and decrease shear forces
    • cushion vulnerable soft tissue sites (ex. diabetics)
    • correct flexible deformities and accomdate rigid deformities (ex. pes planovalgus)
    • eliminate painful motion (ex. hallux rigidus)
    • replace lost motion, improve gait and ambulation (ex. ankle fusion)
  • Options
    • type of stabilization
      • static: rigid device, supports body segment in fixed position
      • dynamic: mobile device, permits body segment motion
      • combination 
    • material
      • metal, plastic, leather, synthetic fabric
    • body region
      • named for joints controlled (ankle and foot = "ankle-foot-orthosis" or AFO)
  • Principles
    • patient-related
      • soft tissue 
        • at risk (diabetics)
        • tolerant to compression and shear forces
      • functional level of patient
        • orthotic should match
      • pathology being addressed
        • soft tissue conditions
        • flexible or rigid deformity
        • painful motion
        • weakness / loss of function
    • orthotic-related
      • three-point pressure control system
      • should be aligned at the approximate anatomic joint
      • design should be
        • simple, easy to put on and take off
        • lightweight
        • durable
        • aesthetically acceptable
Foot Orthoses
  • Shoes
    • shoes are a type of orthosis
    • can be modified to correct or accommodate deformity, minimize painful motion and optimize gait mechanics
    • shoe selection
      • extra depth shoe
        • additional space allows for placement of foot orthosis and can accomodate foot deformity 
      • stiff, supportive shoe
        • flexible foot (ex. flexible pes planovalgus)
      • soft, accommodating shoe with shock-absorbing sole (running shoe)
        • rigid, bony foot
      • custom shoe
        • severe deformity (ex. Charcot foot)
    • shoe modifications
      • can be internal (placed inside the shoe) or external (built up outside the shoe)
        • internal modifications are more mechanically effective but reduced space in shoe
        • external modifications preserve shoe volume but affect cosmesis and are more prone to wear
      • can modify heel, sole or both
      • adjustable closures
        • laces, elastic laces, velcro
        • high top lace up sneakers may help patients with poor distal proprioception
          • provides feedback more proximally to help with balance
      • sole excavation and padding
        • excavation makes room for bony prominences
        • padding cushions painful sites
          • metatarsal pads, toe crest, scaphoid pad
      • cushioned heel  
        • soft pad with compressible material cushions heel
        • helpful for painful heel pad atrophy
      • flares  
        • material added to external medial or lateral shoe
        • provides wider base of support and increases medial-lateral stability
        • useful for ankle instability
          • lateral flare resists inversion
          • medial flare resists eversion
      • wedges
        • internal or external
        • sole, heel or both
        • lateral sole wedge useful for pes cavovarus with fixed forefoot pronation, allowing entire forefoot to reach the ground without compensatory hindfoot varus
        • medial wedge useful for flexible pes planovalgus (posterior tibial tendon dysfunction) corrects hindfoot valgus  
        • heel wedges useful for fixed varus/valgus knee deformity
          • lateral heel wedge unloads medial compartment of the knee
      • heel lift
        • useful for equinus deformity or leg length discrepancy
      • rocker soles
        • helps transfer body weight forward
        • can destabilize the knee by transferring body weight forward rapidly
          • pay careful attention when prescribing to patients with balance or proprioception issues
        • types 
          • mild rocker  
            • most common
            • mild angle at toe and heel
            • relieves metatarsal head pressure and assists witeh forward propulsion
          • heel-to-toe rocker  
            • more angled at toe and heel
            • reduces pressure at heel strike and need for ankle motion
            • useful for patients with ankle or subtalar arthritis or fusion, midfoot amputation or calcaneal ulcers 
          • toe only rocker  
            • angled at toe
            • increases weight bearing proximal to metatarsal heads
          • severe angle rocker  
            • more angled at toe
            • further decreases pressure distal to metatarsal heads
            • useful for relief of metatarsal head or toe tip ulcerations
          • negative heel rocker  
            • angled at toe and midfoot, with heel height lower than that of sole
            • useful to accommodate fixed dorsiflexion deformity
          • double rocker  
            • two shorter rocker soles centered over the forefoot and hindfoot
            • reduces pressure at midfoot
            • useful for midfoot prominences, such as Charcot foot
      • extended shank
        • embedded between the layers of the sole
        • can be carbon fiber or steel
        • functions as a splint, to reduce forefoot and/or midfoot motion
        • useful for hallux rigidus (Morton's carbon-fiber extension) and midfoot arthritis 
  • Foot orthoses (inserts/inlays)
    • Heel cup 
      • rigid plastic insert
      • covers plantar surface of the heel and extends posteriorly, medially and laterally
      • useful to prevent lateral calcaneal shift in flexible pes planovalgus
    • University of California Biomechanics Laboratory (UCBL) orthosis   
      • constructed with rigid plastic over a cast of the foot held in maximum manual correction
      • includes the heel and midfoot, with rigid medial, lateral and posterior walls
      • holds the heel in a vertical neutral position
      • designed for flexible pes planovalgus
        • if deformity is rigid, the UCBL will become painful and could lead to skin breakdown
    • Longitudinal arch support
      • can be applied medially or laterally 
      • prevents depression of subtalar joint and corrects for pes planus
Ankle Orthoses
  • Arizona brace  
    • combination of a UCBL and lace-up ankle support
    • useful for flexible pes planovalgus
      • provides more rigid hindfoot support
  • Ankle foot orthosis (AFO)
    • construction
      • composed of a footplate, calf support and a calf band
      • can be made of plastic, metal and leather
    • indications
      • correct or prevent ankle deformity by assisting in muscular weakness or overactivity involving ankle dorsiflexion, plantarflexion, inversion or eversion
      • ankle position indirectly affects knee stability with ankle plantarflexion providing a knee extension dorce and ankle dorsiflexion providing a knee flexion force
    • types
      • divided broadly into non-articulating and articulating
      • non-articulating  
        • more aesthetically pleasing
        • constructed of plastic, composite materials or leather and metal
        • functionally places a flexion force on the knee during weight acceptance because they are positioned in neutral ankle position
        • does not allow gradual eccentric plantarflexion in early stance
        • the trim lines of plastic AFOs determine the degree of flexibility in the late stance phase
          • described as having maximal, moderate or minimal resistance to ankle dorsiflexion
      • articulating  
        • allows a more natural gait pattern and adjustment of plantarflexion and dorsiflexion
        • adjustable ankle joints can be set to the desired range of ankle motion
        • mechanical ankle joints
          • control or assist ankle dorsiflexion or plantarflexion by means of stops or assists
          • also control medial-lateral stability of the ankle joint
          • limits on ankle motion affect knee stability
            • unrestricted plantarflexion allows normal weight acceptance in early stance
            • plantarflexion causes a knee flexion moment during weight acceptance
            • dorsiflexion stop provides a knee extension moment during late stance
    • specific designs
      • posterior leaf spring (PLS) AFO  
        • most common AFO
        • narrow calf shell and narrow ankle trim line behind malleoli
          • used for compensating weak ankle dorsiflexors and resisting ankle plantarflexion
          • no medial-lateral control
        • useful for foot drop
      • solid AFO  
        • wider calf shell with trim line anterior to malleoli
          • prevents plantarflexion, as well as varus/valgus deviation
      • hinged AFO  
        • adjustable ankle hinges can be set to the desired range of ankle dorsiflexion or plantarflexion (fixed)
        • limit motion for multiplanar ankle instability or ankle pain 
        • useful for spina bifida patients with mid-lumbar level function  
      • ground reaction AFO  
        • plastic extends proximally over the pretibial area and distal trim line extends to the forefoot 
        • provides maximal resistance to plantarflexion and encourages knee extension
        • useful for cerebral palsy patients with incompetent or overly lengthened triceps surae and mild crouch gait
      • patellar tendon bearing AFO  
        • allows weight distribution to patellar shelf
        • reduces weight bearing forces through foot
      • immobilization AFO (ex. CAM walker)  
        • simple off-the-shelf AFO
        • removable protection for lower extremity injuries that require immobilization but permit weight bearing and casting is unnecessary 
        • ex. ankle sprain, stable ankle fracture, Achilles rupture
      • free motion ankle joint  
        • unrestricted ankle dorsiflexion and plantarflexion
          • unrestricted dorsiflexion allows calf muscle strengthening and stretching of the plantarflexors (ex. Achilles)
          • unrestricted plantarflexion allows normal weight acceptance in early stance  
        • provides only medial-lateral stability
        • useful for ankle ligamentous instability 
      • plantarflexion ankle joint stop
        • restricts plantarflexion but allows unrestricted dorsiflexion
        • provides a knee flexion moment during weight acceptance 
          • should not be used in patients with quadriceps weakness
        • useful for patients with foot drop during swing phase and flexible pes equinus 
      • dorsiflexion ankle joint stop  
        • restricts dorsiflexion but allows unrestricted plantarflexion
        • promotes a knee extension moment during the loading response
          • prevent buckling of the knee in stance in presence of quadriceps or plantarflexion weakness
        • useful for patients with weakness of plantarflexion during stance
      • limited motion ankle joint stop
        • restricts both dorsiflexion and plantarflexion
        • useful for global weakness of muscles around ankle joint
      • dorsiflexion assist spring joint 
        • coil spring in the posterior channel 
        • counteracts plantarflexion and aids dynamic dorsiflexion during swing phase
        • useful for dorsiflexion weakness with preserved ankle motion 
      • varus-valgus correction straps (T-straps)  
        • strap contacts skin medially and buckled to the lateral upright is used for valgus correction  
        • strap attached laterally and buckled on the medial upright is used for varus correction
      • supramalleolar orthosis (SMO)  
        • shortest of the AFOs, ending right above the malleoli
        • controls varus/valgus and supports heel in neutral vertical position
        • useful for flexible pes planus, planovalgus, hyper-pronated foot
Knee Orthoses
  • Knee ankle foot orthosis (KAFO)
    • construction
      • consist of an AFO with medial uprights, a mechanical knee joint and two thigh bands
      • can be made of metal, plastic and leather
      • quadrilateral or ischial containment brim limits the weight bearing of the thigh, leg and foot
    • indications
      • quadriceps weakness or paralysis, to maintain knee stability
      • flexible genu varum or valgum
      • more difficult to place and remove than AFOs
      • not recommended for patients with moderate to severe cognitive dysfunction
    • specific designs
      • double upright metal KAFO  
        • most common
        • AFO with two metal uprights extending proximally to the thigh to control knee motion and alignment
        • consists of a mechanical knee joint and two thigh bands between the two uprights
      • Scott Craig orthosis  
        • cushioned heel with a T-shaped foot plate for medial-lateral stability
        • ankle joint with anterior and posterior adjustable stops, double uprights, a pretibial band, a posterior thigh band
        • knee joint with pawl locks and bail control
        • hip hyperextension allows the center of gravity to fall behind the hip joint and in front of the locked knee and ankle joints
        • with 10° of ankle dorsiflexion alignment, a swing to or swing through gait with crutches is possible
        • used for standing and ambulation in patients with paraplegia from a spinal cord injury 

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