Principles of orthotics Flashcards
How to develop an orthotic perscription
- evaluate examination findings to indentify: impairments, activity/participation restrictions
- develop specific goals for orthosis
- design orthosis that applies forces necessary to achieve orthotic goals
Review of examination findings: limitations of functional activities may be caused by…
- insufficient limb/joint movement
- abnormal limb/joint movement
- excessive limb/joint movement
- limb/joint deformity/alignment
developing goals for orthosis
what are the four general categories
- assist joint movement when joint movement is insufficient (weakness)
- stabilize joint by limiting motion when joint movement is excessive, abnormal, or unwanted
- protect joint from excessive, unwanted or deleterious loading/forces that may cause pain or injury
- assist in management of joint/skeletal deformities
Using biomechanical principles when designing orthosis
force application to produce movement when insufficent joint movement
- designed that store and release energy
- manipulate the GRF vector or LOG to produce movement
- use functional electrical stimulation to substitute for weak muscles
Using biomechanical principles when designing orthosis
for application to limit, control, or stop movement (when joint movement is abnormal or excessive)
- use 3-4 point counterforce systems or force couples
- designed that enhance rigidity across joints or slow movement
- manipluate GRF vector or LOG to stop/restrain unwanted movement
LOG = line of gravity
How to manipulate LOG to influence ankle and knee
- indirect control of knee position
- ankle in DF modifies LOG to create a flexion moment at knee
- ankle in PF modifies LOG to create and extension moment at the knee
Factors to consider when choosing biomechanical methods to achieve orthotic goals
- least control that is effective
- interferes least with normal movement
- minimizes energy cost
- applies force close to impairments
- minimizes negative side effects
- maximizes all function
temporal Appliances
- use less expensive splinting /casting materials, elastic bandages or tape
- may not be safe for use outside of clinical setting
- but can observe and evaluate proposed orthotic solution
Ankle foot orthosis components
- foudation
- ankle control
- foot control
- superstructure
AFO: foundation
what is it and describe the two types
- shoe+insert
- insert - plastic carbon fiber
- portion of orthosis that contacts plantar surface of patients foot
- must be worn with shoe that closes high on dorsum of foot
- stirrup-metal
- riveted to bottom of shoe
- heavier than plastic insert foundations
AFO: ankle control how do most AFOs control ankle
- limiting plantarflexion and/or DF
- assisting motion
Plastic:
- adjust trimlines: narrow = more movement wider= more stability
- energy storing material: provide motion assist
- mechanical block to motion
Ankle control
energy storing material
- fiberglass, carbon fiber and kevlar orthosis
- provides DF assist
- best for foot drop with mild to moderate ankle instability
- contraindicated in those with spasticity, edema
how do these types of orthotics work?
Energy storage and release
- similar to a diving board storing and releasing energy
- dynamic response prosthetic foot and orthosis
Ankle control: mechanical block
- plastic AFO with posterior stop
- limits PF ROM
- produces flexion moment at knee
- prevents knee hyperextension
Ankle control
metal ankle joints
orthotics
- free motion - provides M/L ankle control
- single adjustable can provide PF stop or DF assist or free motion
- double adjustable posterior channel: can provide PF stop or DF assist or free motion
- double adjustable anterior channel can provide DF stop of PF assist or free motion
