Lower Extremity

Question 1

How do you determine stirrup length?

Answer 1

2 times height of distal tip of medial malleolus plus width of heel plus 1/4” (6 mm)

Question 2

How do you determine band length?

Answer 2

Half circumference + 1.5 in (38 mm)

Question 3

What are the minimum clearances for ankle joints and knee joints?

Answer 3

Knee: medial side 1/4” (6 mm) - lateral side 1/8” (3mm)
Ankle: lateral side 3/16” (5 mm) - medial side 1/4” (6 mm)

Question 4

In a conventional KAFO what changes could you use to reduce recurvatum?

Answer 4

Shallow bands
Move calf band up and distal thigh down (moving them closer)
Increase Heel Height

Question 5

What problems could you encounter moving the bands?

Answer 5

Peroneal Nerve Impingement

Limited Knee Flexion of Orthosis

Question 6

How much plantar flexion would you allow a patient who has suffered a CVA?

Answer 6

Neutral

Question 7

How do you determine if a patient requires locks on his KAFO versus free knee?

Answer 7

Hip &/or extensor weakness

Question 8

What do you recommend for a patient who exhibits foot slap at heel strike?

Answer 8

An AFO- conventional or plastic/dorsi-assist and/or plantarstop

Question 9

What is Legge-Calve-Perthes disease?

Answer 9

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.

Question 10

Name 3 orthoses used for Legg-Calve-Perthes?

Answer 10

Atlanta Scottish Rite, Toronto, Newington

Question 11

Name 3 orthoses for the treatment of hip dysplasia

Answer 11

Freak pillow, pavlik harness, ilfeld splint

Question 12

what is tibial torsion?

Answer 12

Difference between knee & ankle joint axes as viewed in the transverse plane

Question 13

How is tibial torsion measured?

Answer 13

with the knee at 90 degrees-measure apex of each malleolus to a surface behind the leg

Question 14

What types of functions devices can be used for excessive pronation of the foot?

Answer 14

FO, UCBL

Question 15

A UCBL is used for control of what part of the foot?

Answer 15

hind foot (calcaneus), subtler joint

Question 16

What is the cause of Charcot Joints in the feet and ankle?

Answer 16

Any neuropathic disease can have Charcot joints associated with it (DM, herpes, syphilis)

Question 17

Evaluation of a patient with a gunshot wound to the hip reveals weak hip flexors. What peripheral nerve is injured?

Answer 17

femoral nerve

Question 18

What is your orthotic recommendation for the gunshot wound patient?

Answer 18

maybe a cane use on the contralateral side

Question 19

what is the name for a contralateral pelvic drop?

Answer 19

Trendelenberg sign or gluteus medium limp

Question 20

describe chondromalacia

Answer 20

softness of the articular cartilage usually involving patella-femoral joint

Question 21

What is your orthotic recommendation for chondromalacia?

Answer 21

Palumbo Orthosis or other patellar stabilizing orthosis

Question 22

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?

Answer 22

proximal, posterior thigh - distal anterior thigh - brace migrates proximally

Question 23

Toe drag is a bigger problem in what phase of gate? Why?

Answer 23

Initial swing – if the toe does not clear the floor the patient takes short steps and may trip

Question 24

Why go diabetics get foot ulcers?

Answer 24

Loss of sensation - patient cannot tell when he is getting blisters or pressure sores that can develop into ulcers if not detected in time

Question 25

What is the advantage of an offset knee joint for treating recurvatum?

Answer 25

puts the weight bearing line anterior to the knee joint, making it unnecessary to to lock the knee

Question 26

describe Guillain Barre and its effects on the patient?

Answer 26

infectious polyneuritis with progressive muscular weakness, distal to proximal, which may lead to paralysis. Prognosis usually if full recovery, though in more severe cases the patient may have some residual weakness in distal extremities.

Question 27

Describe Charcot-Marie Disease

Answer 27

Inherited progressive neuromuscular atrophy characterized by progressive weakness of he distal muscles of arms and feet, usually develops in childhood

Question 28

When would you recommend a bail lock on a KAFO instead of drop locks?

Answer 28

Only one functional hand, when crutches or canes are used with bilateral KAFOs

Question 29

Name 2 contraindications for plastic AFOs

Answer 29

Uncontrolled edema | sensitive skin

Question 30

Name 2 methods of minimizing knee flexion torque at initial contact in a lower extremity orthosis

Answer 30

beveled, undercut or SACH heel

Question 31

What implications do weak weak hip flexors have in your design of a KAFO?

Answer 31

a lightweight design could encourage hip flexion at swing phase

Question 32

For what diagnoses would you recommend a rocker bottom shoe?

Answer 32

Diabetes, arthritis, ankle fusion. etc

Question 33

What is the RX rational for a rocker bottom shoe

Answer 33

simulate normal foot mechanics and promote even weight bearing distribution in a patient with limited or no ankle motion

Question 34

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.

Answer 34

Light weight KAFO, offset or drop lock knee, solid plastic AFO section with rocker bottom shoe or double adjustable ankle joints

Question 35

How would you trim the AFO section for the polio patient? Why?

Answer 35

Solid Ankle, anterior trim, flail ankle needs stability in all planes

Question 36

6 weeks post ACL repair- how do you cast? What 2 mechanical principles do you want?

Answer 36

You want the cast in slight flexion to prevent hyperextension and to control rotation

Question 37

Name 2 reasons why you might not use pretibial AFOs for a patient who walks with crouched gait?

Answer 37

Hip flexion Contracture Lack of Ankle ROM Inability to don

Question 38

Give 4 contraindications for RGOs

Answer 38

``` Obesity Hip flexion contracture +20 degrees Spasticity Non-plantargrade foot Hip Dislocation ```

Question 39

Name 3 clinical signs of Charcot Joints at ankle mortise

Answer 39

``` swelling instability excessive joint mobility pain anesthetic foot visual deformity ```

Question 40

Name 3 mechanical principles for treatment of Charcot joints.

Answer 40

Immobilize in total contact AFO Minimal Weight Bearing Rocker Bottom

Question 41

Name 3 signs in evaluation of heel spur pain

Answer 41

values foot pes planes localized pain @ loading

Question 42

Name 2 mechanical principles for treating the above

Answer 42

Distribute & reduce pressure in arch support UCB for hind foot &/or forefoot control

Question 43

Where should you place the mechanical hip

Answer 43

1/2 " anterior 1" superior to greater trochanter

Question 44

How would elevating the shoe heel effect a solid ankle AFO?

Answer 44

increase knee flexion moment at heel strike

Question 45

What effect would posterior placement of knee joints have on a KAFO

Answer 45

migrates proximally with pressure on anterior calf cuff

Question 46

what modifications can you make to a plastic KAFO to reduce recurvatum?

Answer 46

trim proximal & distal sections closer to the knee-pad shells- shallow shells

Question 47

why would you choose a metal AFO over plastic for a patient with Charcot joints?

Answer 47

prevent skin breakdown due to insensate foot

Question 48

What are the stance phases of gait & what is the hip position through each?

Answer 48

``` initial contact (heel strike) - 30 degrees of flexion loading response (foot flat) - 25 - 30 deg flexion midstance - 20 deg flexion to 5 deg extension terminal stance ```

Question 49

How can you prevent a knee orthosis from migrating down?

Answer 49

supracondylar wedge - supramalleolar strap, attach to a footplate, lightweight belt