CFO Case Analysis & Practical Application 3 — Questions and Answers
Question 1: During a gait analysis, you observe that a patient with a custom foot orthosis exhibits excessive midstance pronation despite a medial rearfoot post. What is the most appropriate next step?
- Add or increase medial forefoot posting to address forefoot varus (Correct answer)
- Replace the orthosis with a softer shell material
- Switch to a lateral rearfoot post
- Increase the heel cup height only
Correct answer: Add or increase medial forefoot posting to address forefoot varus
Persistent midstance pronation despite rearfoot posting often indicates an unaddressed forefoot varus that requires medial forefoot correction.
Question 2: A patient with a leg length discrepancy of 12 mm presents with chronic low back pain. The fitter confirms the discrepancy is structural. What is the standard orthotic approach?
- Begin with a heel lift of approximately one-half the measured discrepancy (Correct answer)
- Provide a full-length lift equal to the total discrepancy immediately
- Use a rocker-bottom sole modification with no lift
- Refer for custom AFO without addressing the LLD first
Correct answer: Begin with a heel lift of approximately one-half the measured discrepancy
Standard practice is to start with roughly half the discrepancy to allow the musculoskeletal system to adapt before progressing to full correction.
Question 3: A patient's custom orthosis causes pain under the first metatarsal head two weeks after dispensing. On inspection, the medial forefoot post appears too high. Which adjustment is most appropriate?
- Grind down the medial post to reduce elevation under the first ray (Correct answer)
- Add a metatarsal pad under the second through fifth heads
- Apply additional medial rearfoot posting
- Replace the top cover with a thicker material
Correct answer: Grind down the medial post to reduce elevation under the first ray
Reducing the medial post height relieves excessive pressure transferred to the first metatarsal head caused by over-correction.
Question 4: A teenager with Sever's disease (calcaneal apophysitis) is seen for orthotic management. Which feature is most important in the prescribed device?
- Heel cushioning or slight heel lift to reduce tension on the Achilles insertion (Correct answer)
- Rigid carbon plate with forefoot extension
- Lateral flare to control rearfoot eversion
- Metatarsal dome to offload the forefoot
Correct answer: Heel cushioning or slight heel lift to reduce tension on the Achilles insertion
Heel cushioning and a slight lift reduce compressive and tensile forces at the calcaneal apophysis, alleviating Sever's disease pain.
Question 5: A patient with hallux rigidus is prescribed an orthosis. Which design feature most effectively reduces pain during the propulsive phase of gait?
- Morton's extension or full-length rigid plate to limit first MTP dorsiflexion (Correct answer)
- Medial heel post to correct rearfoot valgus
- Soft accommodative shell with no rigid component
- Deep heel cup to stabilize the rearfoot
Correct answer: Morton's extension or full-length rigid plate to limit first MTP dorsiflexion
A Morton's extension or rigid plate prevents painful dorsiflexion at the fused or arthritic first MTP joint during toe-off.
Question 6: When fitting an off-the-shelf (OTS) orthosis for a patient with mild plantar fasciitis, which sizing criterion takes priority?
- The OTS device should fit the patient's shoe size with the arch apex aligning under the navicular (Correct answer)
- The device should be the largest size that fits in the shoe
- The heel cup should be 2 cm wider than the patient's heel
- The forefoot length should extend past the first metatarsal head
Correct answer: The OTS device should fit the patient's shoe size with the arch apex aligning under the navicular
Proper OTS fitting requires the arch apex to align anatomically under the navicular to provide genuine arch support.
Question 7: A patient with multiple sclerosis presents with foot drop and significant spasticity. Which AFO design is most appropriate compared to a standard posterior leaf spring?
- Solid AFO with anterior trim lines to resist plantarflexion spasticity (Correct answer)
- Posterior leaf spring AFO trimmed medial to the malleoli
- Dynamic AFO with dorsiflexion assist spring
- Supramalleolar orthosis with medial posting
Correct answer: Solid AFO with anterior trim lines to resist plantarflexion spasticity
Spasticity-driven plantarflexion requires a solid, rigid AFO with anterior trim lines to resist the spastic pull rather than a flexible energy-return design.
CFO Case Analysis & Practical Application 3
During a gait analysis, you observe that a patient with a custom foot orthosis exhibits excessive midstance pronation despite a medial rearfoot post.
What is the most appropriate next step?