Which description best fits a posterior leaf spring orthosis?

• A. A plastic AFO with a trim line posterior to the malleoli and offers minimal medial or lateral ankle support
• B. A rigid knee-ankle-foot device with solid ankle support
• C. A full-length foot orthosis with strong medial ankle support
• D. A dorsiflexion strap only without trim lines behind the malleoli

Answer: (A)

A posterior leaf spring orthosis is a dynamic ankle–foot device that provides controlled dorsiflexion assistance without rigidly stabilizing the ankle. Its flexible “leaf” runs along the back of the leg and foot, stored energy as the foot moves into plantarflexion and then releases it to help lift the forefoot during swing. The trim line sits behind the malleoli, allowing this posterior leaf to flex while offering only minimal medial-lateral ankle support.

The description that matches this is a plastic AFO with a trim line posterior to the malleoli and minimal medial or lateral ankle support. This design emphasizes dynamic dorsiflexion aid rather than rigid stability, which is why it best fits the posterior leaf spring concept.

The other options describe devices that are rigid or provide substantial ankle stabilization (solid ankle support or full-length strong medial support) or a strap-only system without a true posterior leaf, which do not align with the posterior leaf spring’s dynamic, lightweight, minimally stabilizing purpose.