Posterior Leaf Spring
Also written as: PLS — Posterior Leaf Spring
A lightweight, flexible AFO design featuring a narrow polypropylene or carbon fibre upright that provides dorsiflexion assistance through elastic recoil during swing phase.
Full Definition
The posterior leaf spring (PLS) orthosis is characterised by a thin, flexible footplate and a narrow posterior upright that acts as a spring, storing energy during loading and returning it to assist foot dorsiflexion in swing phase. It is most appropriate for patients with mild drop foot and relatively normal subtalar joint motion who do not require significant mediolateral ankle control. Because the trim lines are set well medial and lateral to the malleoli, the PLS offers less coronal-plane stability than a solid AFO. In editorial review, 'posterior leaf spring' is written as three words without hyphens when used as a noun; hyphenate the compound when used attributively (e.g., 'posterior-leaf-spring orthosis'). The abbreviation PLS is acceptable after first-use expansion.
Usage
Usage note: Do not hyphenate when used as a noun phrase; hyphenate when used as a compound modifier before a noun.
In Context
- "A posterior leaf spring was selected in preference to a solid AFO to allow the patient to wear standard footwear." — Orthotic prescription rationale
- "The PLS orthosis is contraindicated where mediolateral ankle stability is compromised." — Clinical decision-support document