Proximal Tibial Brim
The upper edge of a lower-limb orthosis that conforms to the proximal tibia, defining the superior boundary of the device and influencing joint control.
Full Definition
The proximal tibial brim is the trimmed superior margin of an ankle–foot or knee–ankle–foot orthosis where the shell ends at or near the proximal tibia. Its height and contour determine how much rotational and varus/valgus control the device exerts at the knee. A higher brim provides greater mediolateral stability, while a lower brim reduces bulk and improves cosmesis. The term is encountered in prescription forms, fitting notes, and modification orders; editors must ensure it is not confused with 'patellar tendon–bearing brim,' which describes a specific anterior relief feature. Accurate documentation of trim-line height in millimetres or anatomical landmarks is expected in clinical records.
Usage
Usage note: Always specify brim height relative to an anatomical landmark (e.g., medial joint line) rather than using vague descriptors such as 'high' or 'low'.
In Context
- "The proximal tibial brim was extended 2 cm to improve mediolateral knee stability during ambulation." — Orthotic modification note
- "Ensure 'proximal tibial brim' and 'patellar tendon–bearing brim' are not used interchangeably in the fitting report." — Editorial checklist for lower-limb orthosis documentation