Test 1 question about AFO

[Katie Fish]

In the question: A patient presents to your clinic with a diagnosis of foot drop due to a common peroneal nerve injury. Which orthosis would be best for this patient?
a. Rigid AFO
b. Articulating AFO with dorsiflexion assist
c. Articulating AFO with plantarflexion stop
d. Posterior leaf spring AFO

answers b and d are both in group c? What makes you the decision to choose one over the other?

[Chrissy Durrough Lugge]

Hi Katie,
In this case when a patient has no spasticity, contracture, or other weakness, the simplest option is likely best. A posterior leaf spring AFO is the lightest weight, will be easiest to don, and will fit in more shoes than a hinged AFO.

Here are a couple links discussing types of AFOs in more details:
– Comparing pre-fab AFOs: https://ejournal.poltekkesjakarta1.ac.id/index.php/OP/article/view/961
– Types of AFOs and indications with some photos: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8392067/
– ANPT resource: https://www.neuropt.org/docs/default-source/cpgs/afo-fes/afo-table-finalb0fb3ba5390366a68a96ff00001fc240.pdf?sfvrsn=76f85d43_2

Hope this helps!
Chrissy

[Katie Fish]

Thank you! I have limited experience with AFO’s and we don’t have a great local orthotist to work with, so I am struggling with these questions. I appreciate the help!

[Chrissy Durrough Lugge]

No problem!

[Harriet Hill]

Hey Chrissy – I am also struggling with AFO types and I have another question about this. The question states this person has foot drop due to common peroneal nerve injury. To me, that would mean their ankle everters may also be affected since the common peroneal connects with both the superficial and deep peroneal nerves. Would this mean there is a chance this patient has lateral ankle instability too? How do I determine from this question that they do not, since a posterior leaf spring doesn’t seem to provide support for medial/lateral instability.

[Chrissy Durrough Lugge]

Hi Harriet,

The patient likely has some lateral ankle instability, especially if walking without orthotics (due to the foot dropping into PF/inversion). A posterior leaf spring AFO will prevent that classic foot drop position by maintaining the ankle in dorsiflexion with neutral eversion/inversion. In most cases, this prepares the foot and ankle well for initial contact and effectively provides that lateral stability. The posterior leaf spring AFO has the advantages listed above in terms of ease of donning, weight, cost, and flexibility of footwear, so it is best to start with this option.

If the patient had spasticity, contracture, or weakness beyond this nerve distribution, a more aggressive AFO may be warranted.

Chrissy

[Harriet Hill]

Ok! That makes sense. Super helpful, thank you!!

[Katie Fish]

Hi! I have another question about AFO’s but not from your study questions. There is no mention about a 3/4 footplate in the Rancho Roadmap. When would you use a 3/4 footplate?

[Chrissy Durrough Lugge]

Hi Katie!

There’s not a ton in the literature about 3/4 footplates. 3/4 footplates are likely more flexible and therefore allow more ankle dorsiflexion during swing phase.

I did find one article indicating that AFOs with full-length footplates produce increased stance phase PF moments compared to no AFOs (wherease 3/4 footplates were no different than no AFOs). That same study found that AFOs with 3/4 footplates resulted in significantly less than normal dorsiflexion in late stance. It was hypothesized that AFOs with full-length footplates increased DF ROM and PF moment in late stance by delaying or impeding heel rise more than the 3/4 footplate. (https://www.sciencedirect.com/science/article/pii/S0003999309001221?via%3Dihub)

It seems that they may increase walking speed. In another study, almost all patients with 3/4 footplates showed an increase in the walking speed, although they were not statistically significant. Meanwhile, the ability of body to move on weight bearing limb and fast weight distribution is the important factor affecting the walking speed. It seems that the 3/4 AFO allowed more dorsiflexion in mid foot; and the third rocker was fulfilled easier during the terminal stance phase. (https://pdfs.semanticscholar.org/4ef1/5e8e617949a7f88e73f017491fad6f553af6.pdf)

[Katie Fish]

Thank you! Have you had any personal experience with 3/4 plate? I had one patient who had it and complained his toes hurt because of the spasticity and they would curl. I suggested to the orthotist to extend the footplate to see if that helped and it was a little better. I wish I had the Rancho roadmap because looking back I think he also needed a PF stop as well for knee hypertension during stance phase.

[Chrissy Durrough Lugge]

I don’t have personal experience with 3/4 footplates. The orthotists with whom I work don’t tend to recommend them, and the evidence hasn’t been compelling enough for me to push for them for any of my patients. A hard footplate ending in the mid-foot doesn’t sound comfortable – with or without spasticity.

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