Posterior Leaf Spring
Also written as: PLS — Posterior Leaf Spring
A trimmed thermoplastic or carbon fibre AFO design characterised by a narrow posterior upright that provides dynamic dorsiflexion assistance through elastic recoil.
Full Definition
The posterior leaf spring (PLS) AFO is a slender, flexible ankle–foot orthosis in which the posterior upright acts as a spring, storing energy during mid-stance and releasing it to assist dorsiflexion during swing phase. The flexibility and control characteristics of a PLS are determined by its trim lines: a narrow trim line produces greater flexibility, while wider trim lines increase mediolateral control. PLS AFOs are indicated for mild-to-moderate foot drop without significant spasticity or mediolateral instability. Editors should ensure 'posterior leaf spring' is not abbreviated to 'PLS' without prior expansion in formal clinical documents, and should not conflate it with solid or hinged AFO designs, which provide different biomechanical functions.
Usage
Usage note: Expand on first use; do not conflate with hinged or solid AFO designs, which offer different biomechanical control.
In Context
- "A posterior leaf spring AFO was selected for its lightweight profile and ability to provide passive dorsiflexion assist without restricting push-off." — Orthotic evaluation and recommendation report
- "Expand 'PLS' to 'posterior leaf spring' on first mention; subsequent uses of the abbreviation are acceptable." — Editorial style note for clinical case study