COF Orthotic Fitting Principles 3

Question 1

When fitting a knee-ankle-foot orthosis (KAFO), the knee joint should typically be set to which position for a patient with quadriceps weakness?

Accepted Answer

Full extension (0 degrees) to provide stability during stance

Answer

Setting the knee joint at 0 degrees (full extension) provides a stable base for stance phase when quadriceps are too weak to prevent knee buckling.

Question 2

A patient with drop foot requires an AFO. Which AFO design preserves the most sagittal-plane motion while still preventing foot drop?

Accepted Answer

Hinged AFO with a dorsiflexion assist spring

Answer

A hinged AFO with dorsiflexion assist spring allows plantarflexion during loading response while providing active assistance into dorsiflexion during swing phase.

Question 3

In orthotic fitting, what does the term 'trim line' refer to?

Accepted Answer

The final edge cut of the thermoplastic orthosis that determines its borders and flexibility

Answer

The trim line is the edge of the thermoplastic material after cutting, and its location determines the rigidity, flexibility, and anatomical coverage of the orthosis.

Question 4

Which material property is most important when selecting thermoplastic for a pediatric AFO that will undergo frequent adjustments?

Accepted Answer

Reheating and reshaping capability (thermoplasticity) with low creep

Answer

Pediatric orthotics require frequent modifications as the child grows, so materials that can be reheated and reshaped without losing structural integrity are preferred.

Question 5

A patient is fitted with a cervical orthosis. Which design provides the GREATEST restriction of cervical flexion and extension?

Accepted Answer

Halo vest orthosis

Answer

The halo vest orthosis is the most rigid cervical immobilization device, providing approximately 94% restriction of flexion/extension compared to soft collars' ~26%.

(COF) Certified Orthotic Fitter Practice Test

(COF) Certified Orthotic Fitter Practice Test

COF Orthotic Fitting Principles 3