Ch 6 - Prosthetic and Orthotics: Lower Limb Orthoses Flashcards
Where is the COG while standing?
Midline and just anterior to the S2 vertebra
What is the Line of gravity (weight line)?
Line passing through the COG to the ground
How many points of pressure are needed in orthotic devices?
3 points of pressure are needed for proper control of a joint
Where does the line of gravity pass through the spine?
Behind the cervical vertebrae, in front of the thoracic vertebrae, and behind the lumbar vertebrae
Where does the line of gravity pass through the hip?
Slightly posterior to the hip joint and tends to passively extend the hip joint
Where does the line of gravity pass through the knee?
Anterior to the knee joint and tends to passively extend the knee
Where does the line of gravity pass through the ankle?
1 to 2 inches anterior to the ankle joint and tends to dorsiflex the ankle
During the “quiet” standing phase, where does the line of gravity pass?
- Posterior to hip joint
- Anterior to knee joint
- Anterior to ankle joint
How are Thermoplastics molded?
Soften and become moldable when heated
– Cold-temp can be molded at temp just above body temp (< 80°C or < 180°F)
What are AFO’s used for?
Weakness affecting the ankle and subtalar joints
What are Posterior leaf spring AFO’s used for?
Flaccid foot drop
Describe a Posterior leaf spring AFO.
Very thin plastic band behind the ankle allowing the patient to overpower the brace during push-off/plantar flexion phase, yet allowing dorsiflexion assist and positioning of the foot during swing phase
Describe a Semirigid plastic AFO.
Trim line is just behind the malleoli and provides increased mediolateral stability of the ankle and dorsiflexion positioning of the foot
What is a Semirigid plastic AFO used for?
Foot drop with some extensor tone and/ or mediolateral instability of the ankle
Describe a Rigid (solid) plastic AFO.
Trim line at the malleoli or anterior to the malleoli with no motion allowed at the tibiotalar or subtalar joint
What is a Rigid (solid) plastic AFO used for?
Highest levels of spasticity/tone
Complete immobilization of the ankle (post op)
Early to moderate Charcot joint
What is a Klenzak joint?
Inserting a spring in the single channel ankle for dorsiflexion assist
What are the 3 options of a Single Channel ankle joint?
– Spring for dorsiflexion assist
– Steel pin for plantar flexion stop
– Both a pin and a spring for dorsiflexion assist and plantar flexion stop
What does a pin in the anterior dual channel ankle joint do?
Block the forward progression of the tibia at midstance (dorsiflexion stop), or to lock the joint in a fixed position
What is a pin in the anterior dual channel ankle joint used for?
Quadriceps muscle is weak
Charcot joint deformity at the ankle
Describe a free motion knee joint KAFO.
Free motion knee joint provides unlimited flexion but usually has a stop to prevent hyperextension
What is a a free motion knee joint KAFO used for?
Patients with genu recurvatum but with enough strength to control the knee in stance and ambulation
Describe an offset knee joint KAFO.
Hinge posterior to the knee joint so the patient’s weight line falls anterior joint, stabilizing the knee during early stance phase
When should an offset knee joint KAFO not be used?
Knee or hip flexion contractures
Plantar flexion stop at the ankle
What is a good KAFO to use in an obese patient with quadriceps weakness?
KAFO with double metal uprights and posterior offset knee joint
Describe a polycentric knee joint for a KAFO.
Provides unlimited knee flexion and extension but has significant added weight and components that require maintenance
What is a Scott-Craig orthosis?
Bilateral KAFOs designed for standing and ambulation in adults with paraplegia
Who is a Scott-Craig orthosis used for?
Complete neurological level at L1 or lower with a more functional and comfortable gait
How is Unsupported standing possible with Scott-Craig orthoses?
Ankles and knees locked, hip stabilization by leaning trunk backwards so COG of the trunk rests posterior to the hip joint, resulting in tightening of the anterior hip capsule and the “Y” ligament
How do patients ambulate with Scott-Craig orthoses?
Crutches or walker using a swing-to or swing-through pattern gait
When is a Reciprocal gait orthosis used?
Upper lumbar paralysis in which active hip flexion is preserved
What does a Reciprocal gait orthosis consist of?
Bilateral HKAFOs with offset knee joints with drop locks, posterior plastic AFOs, thigh pieces, custom-molded pelvic girdle, hip joints, and a thoracic extension with Velcro straps
What does a sagittal plane knee orthosis provide?
Limits hyperextension of the knee (genu recurvatum)
What does an axial rotation knee orthosis provide?
Mediolateral and axial control
What does a coronal plane knee orthosis provide?
Mimics anatomic knee joint function
What does adding a footplate to knee immobilizer do?
Dec rotational instability of the knee
What is a Swedish Knee cage used for?
Controls minor to moderate knee hyperextension/ genu recurvatum due to ligamentous or capsular laxity
What is a Lenox-Hill derotation orthosis?
Knee orthosis designed for control of knee axial rotation in addition to anterior-posterior and medial-lateral control
What is a Lenox-Hill derotation orthosis used for?
Protection and management of sports injuries to the knee (ACL injuries)
