Lower Extremity Oral Questions Flashcards
How do you determine stirrup length?
2 times height of distal tip of medial malleolus plus width of heel plus 1/4” or 6mm
How do you determine band length?
half circumference plus 1 1/2” or 38mm
What are the minimum clearances for ankle joints and knee joints?
Knee: medial side: 1/4” or 6mm - lateral side: 1/8” or 3mm
Ankle: medial side: 1/4” or 6mm - lateral side: 3/16 or 5 mm
In a conventional KAFO, what changes could you use to reduce recurvatum?
Shallow bands, move calf band up – distal thigh down – move these two closer, increase heel height
What problems could you encounter in moving the bands?
Peroneal nerve impingement, limited knee flexion of orthosis
How much plantar flexion would you allow a patient who has suffered a CVA?
neutral
How do you determine if a patient requires locks on his KAO versus free knee?
Hip and/or knee extensor weakness
What do you recommend for a patient who exhibits foot slap at heel strike?
An AFO – conventional or plastic/dorsi-assist and/or plantar stop
What is Legge-Calve-Perthes disease?
Avascular Necrosis of the femoral head usually occurring in boys ages 9-14. Femoral head will return to normal if the leg is abducted and internally rotated to place the femoral head into the acetabulum.
Name 3 orthoses used for Legge-Calve-Perthes?
*Atlanta (Scottish Rite)
*Toronto
*Newington
–Orthoses is set up internally rotated and abducted about 45 degrees
Name 3 orthoses for the treatment of Hip Dysplasia
*Frejka pillow
*Pavlik harness
*ILfeld splint
–Orthoses is set up in a flexed ad abducted position
What is tibial torsion?
Difference between knee and ankle joint axes as viewed in the transverse plane
How is tibial torsion measured?
With the knee at 90 degrees 00 measure apex of each malleolus to a surface behind the leg
What type(s) of functional device can be used for excessive pronation of the foot?
Foot orthotic or UCBL
A UCBL is used for more control of what part of the foot?
hind foot (calcaneus), sub-talar joint
What is the cause of Charcot joints in the feet and ankle?
Any neuropathic disease an have Charcot joints associated with it (diabetes, herpes, syphilis)
Evaluation of a patient with a gunshot wound to the hip reveals weak hip flexors. What peripheral nerve is injured?
Femoral nerve
What is your orthotic recommendation for the above? – (Femoral nerve injury)
Maybe a cane used on the contralateral side
What is the name for a contralateral pelvic drop?
Trendelenberg sign or gluteus medius limp
Describe chondromalacia
Softness of the articular cartilage usually involving patello-femoral joint
What is your orthotic recommendation for chondromalacia?
Palumbo orthosis or other patellar stabilizing orthosis
A patient’s KAFO has free motion knee, but the mechanical joint is 1” distal to the anatomical joint. In flexion the resulting pressures will be?
Proximal, posterior thigh - distal, anterior thigh - brace migrates proximally
Toe drag is a bigger problem in what phase of gate? Why?
Initial swing – if the toe does not clear the floor the patient takes short steps and may trip
Why do diabetics get foot ulcers?
Loss of sensation – patient cannot tell when he is getting blisters or pressure sores that can develop into ulcers if not detected in time
What is the advantage of an offset knee joint for treating recurvatum?
Puts the weight bearing line anterior to the knee joint, making it unnecessary to lock the knee
Describe Guillain Barre and its effects on the patient?
Infectious polyneuritis with progressive muscular weakness, distal to proximal, which may lead to paralysis. Prognosis usually is full recovery, though in more severe cases the patient may have some residual weakness in distal extremities
Describe Charcot-Marie-Tooth disease
Inherited progressive neuromuscular atrophy characterized by progressive weakness of the distal muscles of arms and feet usually develops in childhood
When would you recommend a bail lock on a KAFO instead of drop locks?
Only one functional hand, when crutches or canes are used with bilateral KAFOs
Name two contraindications for plastic AFOs
*uncontrolled edema
*sensitive skin
Name two methods of minimizing knee flexion torque at initial contact in a lower extremity orthosis?
*Beveled
*undercut
*SACH heel
What implications do weak hip flexors have in your design of a KAFO?
A lightweight design could encourage hip flexion at swing phase
For which diagnoses would you recommend a rocker bottom shoe?
*Diabetes
*Arthritis
*Ankle fusion
What is the RX rational for a rocker bottom shoe?
Simulate normal foot biomechanics and promote even weight bearing distribution in a patient with limited or no ankle motion
A polio patient has a flail ankle, good knee muscles, good hip muscles, full ROM at knee with 25 degrees recurvatum. Knee buckles when tired. What orthosis do you recommend? Describe the mechanical principles.
Lightweight KAFO, offset or drop lock knee, solid plastic AFO section with rocker bottom shoe or double adjustable ankle joint
How would you trim the AFO section for the above polio patient? Why?
Solid ankle, anterior trim, flail ankle needs stability in all planes
Six weeks post ACL repair – how do you cast? What two mechanical principles do you want?
*Cast in slight flexion
1. prevent hyperextension
2. Control rotation
Name 2 reasons why you might not use pretibial AFOs for a patient who walks with a crouch gait?
- Hip flexion contracture
- Lake of ankle ROM/inability to don
Give 4 contraindications for RGOs
- obesity
- hip flexion contracture +20 degrees
- Spasticity
- non-plantargrade foot
- hip dislocation
Name 3 clinical signs of Charcot joints at ankle mortise.
- Swelling
- instability
- excessive joint mobility
- pain
- anaesthetic foot
- visual deformity
Name 3 mechanical principles for treatment of Charcot joints
- Immobilize in total contact AFO
- Minimal weight bearing
- Rocker bottom
Name 3 signs in evaluation of heel spur pain
- Valgus foot
- pes planus
- localized pain at loading
Name 2 mechanical principles for treating the above (heel spur pain)
- distribute and reduce pressure in arch support
- UCB – for hindfoot and/or forefoot control
Where should you place the mechanical hip joint?
1/2” anterior and 1” superior to greater trochanter
How would elevating the shoe heel effect a solid ankle AFO?
Increases knee flexion moment at heel strike
What effect would posterior placement of knee joints have on a KAFO?
Migrates proximally with pressure on anterior calf cuff
What modifications can you make to a plastic KAFO to reduce recurvatum?
*Trim proximal and distal sections closer to the knee
*pad shells
*shallow shells
Why would you choose a metal AFO over plastic for a patient with Charcot joints?
Prevent skin breakdown due to insensate foot
What are the stance phases of gait and what is the hip position through each?
*Initial contact (heel strike) - 30 degrees flexion
*Loading response (foot flat) - 25-30 degree flexion
*Midstance - 20 degrees flexion to 5 degrees extension
*Terminal stance (heel off) - 10 degrees extension
*Pre-swing (push-off) - 10 degrees extension
How can you prevent a knee orthosis from migrating down?
*Supracondylar wedge
*Suprapatellar strap
*attach to foot plate
*lightweight belt
What is the basic theory facture bracing?
Using hydrostatic pressure to stabilize the fracture, micro motion at fracture site promotes healing, mobilization of joints above and below the fracture decreases rehabilitation time
How would you treat a stable, ten day old, distal 1/3 femoral fracture with acute signs of swelling and pain absent?
Functional femoral fracture brace with free knee and ankle
What would you recommend for a 3 week old tibial plateau fracture
AK fracture brace with free knee and ankle
Would you fit a tibial fracture brace on a patient with an open wound on the tibia?
No, fracture bracing is contraindicated with open wounds
What could you do to a fracture brace to better align a lateral or medial tibial plateau fracture?
Stress brace into a varus or valgus position
What is the best position for a patient to be in when being fitted with a tibial fracture brace?
Sitting when legs dangling knee at 90 degrees
Should you put a femoral fracture brace on a proximal femoral fracture?
No, never brace femoral fractures above the distal 1/3rd.
