What is undercast padding and what does it do in orthopaedic casting?

Undercast padding (also called orthopaedic wadding, cast padding, or cast liner) is a soft, compressible bandage applied over the stockinette and under the hardening cast material (plaster of Paris or fiberglass). It serves three clinical functions: (1) Cushioning — provides a compressible layer between the skin and the rigid cast that protects against pressure sores, particularly over bony prominences such as the malleoli, tibial crest, ulnar styloid, and radial styloid; (2) Swelling accommodation — the padding layer allows the limb to swell in the early post-injury phase without the cast becoming dangerously constrictive — the padding compresses as the limb swells, providing a buffer before the cast becomes tight; (3) Smooth inner cast surface — the padding layer creates a smooth, even surface for the cast material to bond to, preventing internal ridges that could cause pressure sores during wear. Without undercast padding, a cast applied directly over stockinette alone would have insufficient cushioning for bony prominences and no swelling accommodation.

What is the difference between cotton and synthetic undercast padding?

Cotton undercast padding (100% cotton or cotton/viscose blend): Highly absorbent — absorbs perspiration from the skin under the cast, helping to keep the skin drier during extended wear. Self-cohesive — cotton fibres bond to themselves, so the padding does not slip or bunch under the cast. Hand-tearable and 'featherable' at the edges (the cotton fibres can be pulled apart to thin the edge of the padding roll, creating a smooth feathered transition rather than a ridge). The feathering property is clinically important for creating even cast edges without internal pressure ridges. Higher absorbency makes cotton the preferred choice for casting over wounds or in cases where wound drainage is anticipated. Synthetic undercast padding (non-woven polyester): Higher loft (more cushioning per unit thickness) than cotton for the same weight. More uniform thickness — does not thin as readily as cotton over bony prominences during cast wear. Moisture-wicking properties in synthetic variants draw moisture away from skin rather than absorbing it. Lower absorbency than cotton — preferred when moisture management is not required. Used extensively under fiberglass synthetic casting.

What is the feathering technique and why does it matter for cast padding procurement?

Feathering refers to the technique of pulling apart the fibres at the edges of each wrap layer of cast padding to create a tapered, thin edge rather than a blunt fold. When cast padding is applied in overlapping spiral layers, the overlapping edge of each layer can create a ridge if the edge is not feathered. This ridge becomes embedded in the hardened cast material and can create a raised pressure line against the skin — potentially causing pressure sores during extended cast wear. Cotton undercast padding feathers easily because the cotton fibres separate naturally when pulled — the edge can be thinned to a near-invisible taper. For procurement, this feathering property is a key quality criterion for cotton padding: a padding product that tears cleanly but does not feather well at the edges will produce ridged cast interiors. When evaluating cotton undercast padding products, request a product sample and confirm that the edges feather smoothly and thin gradually rather than tearing abruptly.

What weights and widths should I specify for undercast padding?

Standard widths for undercast padding are: 5 cm for fingers and small paediatric limbs; 7.5 cm for wrist and small forearm; 10 cm for forearm and ankle/lower leg — most commonly procured; 15 cm for knee, upper arm, and thigh; 20 cm for large limbs. Standard weights are 75, 80, or 90 g/m² — heavier padding provides more cushioning per layer but adds more bulk under the cast. For most standard casting applications, the lightest weight appropriate for the clinical need provides the best cast fit — thicker padding takes up more space inside the cast. Standard roll lengths are 2.7 m or 3 m (metric/international suppliers) or 4 yards (approximately 3.65 m, North American market). Standard cast rolls and North American plaster room procurement typically use 4-inch (10 cm) and 6-inch (15 cm) widths most heavily. Orthopaedic departments should procure a range of widths to accommodate different body parts and patient sizes.

How many layers of undercast padding are applied and how are bony prominences protected?

Standard cast padding technique applies two to three overlapping spiral layers of undercast padding over the stockinette, with approximately 50% overlap per layer. This provides two to three thicknesses of padding throughout the cast. Bony prominences require additional protection: standard protocol adds extra padding layers over anatomical areas that are vulnerable to pressure sores. These include: malleoli (inner and outer ankle), tibial crest (shinbone), heel, radial and ulnar styloids (wrist), radial head, fibular head, and any other bony protrusions within the cast. Extra padding is applied locally over each prominence before the standard spiral layers — this builds up additional cushioning at the points of highest pressure risk. For procurement, consider stocking extra small-width rolls (5 cm or 7.5 cm) alongside the standard widths specifically for bony prominence spot-padding applications.

Kingphar Medical Group

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9/5 2026

Undercast Padding (Orthopaedic Wadding): Specifications & Procurement Guide 2026

Orthopaedic · Casting · Procurement Guide

Undercast Padding
(Orthopaedic Wadding):
Specifications & Procurement Guide 2026

Undercast padding is the cushioning layer between the stockinette and the hardened cast — preventing pressure sores over bony prominences and accommodating post-injury swelling. Cotton and synthetic types have different properties for different casting systems. The feathering characteristic of cotton padding directly affects cast quality. This guide covers material selection, standard specifications, and a procurement checklist.

Cotton vs synthetic Feathering technique explained Bony prominence protection Standard weights and widths Casting layer sequence Procurement checklist

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Primary function

Cushioning

Between skin and cast material — protects bony prominences from pressure sores and accommodates post-injury swelling under the hardened cast.

Standard widths

5–20 cm

5 / 7.5 / 10 / 15 / 20 cm. Source: Henso Medical product specifications. 10 cm most commonly procured for general adult casting.

Standard weights

75–90 g/m²

75 / 80 / 90 g/m² standard options. Source: Henso Medical product specifications. Heavier = more cushioning per layer but more bulk under cast.

Standard roll lengths

2.7–3 m

2.7 m or 3 m (metric suppliers) / 4 yards (3.65 m, North American format). Source: Henso Medical, Cardinal Health Webril product data.

Undercast padding — also called orthopaedic wadding, cast padding, or cast liner — is a soft, compressible material applied in spiral overlapping layers over the stockinette and beneath the hardened cast. It is the cushioning layer that prevents the rigid cast from creating direct pressure against the skin, and it provides the compliance needed for the limb to swell in the early post-injury phase without the cast becoming dangerously tight.

For procurement managers, the key decisions are: cotton or synthetic (matched to the casting system), weight (determining cushioning thickness), and width range for different body parts. For the casting layer context — including where undercast padding fits relative to stockinette — see our Stockinette Specifications Guide.

Section 01

Where Undercast Padding Fits: The Casting Layer Sequence

Skin

Baseline — patient's skin. Skin care lotion may be applied for dry or fragile skin before stockinette.

Stockinette

Seamless knit cotton tube — slides over the limb. Smooth skin interface. No cushioning function. See Stockinette Specifications Guide.

Undercast padding ← This product

Applied in 2–3 overlapping spiral layers over the stockinette with approximately 50% overlap. Provides cushioning over the entire limb. Extra padding layers added locally over bony prominences. Stockinette ends folded back over padding at cast margins before final cast layers.

Cast material

Plaster of Paris bandage or fiberglass casting tape — applied over the padding in overlapping layers. Hardens to immobilise the fracture.

Section 02

Cotton vs Synthetic: Material Selection Guide

Standard — POP and general casting

Cotton Undercast Padding

Self-cohesive Featherable Highly absorbent Hand-tearable

100% cotton or cotton/viscose blend. Self-cohesive — cotton fibres bond to themselves without adhesive, preventing the padding from slipping or bunching under the cast. Feathers smoothly at edges (cotton fibres pull apart to create a tapered edge — critical for smooth cast interiors). Highly absorbent — absorbs perspiration and wound drainage. Hand-tearable without scissors. Source: BSN Medical Specialist 100 product documentation.

Best for: Plaster of Paris (POP) casting, general orthopaedic casting, casting over wounds where absorbency is needed, any setting where feathering is clinically important.

Fiberglass / synthetic casting

Synthetic Undercast Padding

High loft Moisture-wicking Conformable Consistent thickness

Non-woven polyester construction. Higher loft (more cushioning per unit thickness) than cotton. More consistent thickness — does not thin as readily at bony prominences during cast wear. Moisture-wicking properties move perspiration away from skin rather than absorbing it. Less prone to bunching under synthetic cast material. Source: BSN Protouch, Dukal product documentation.

Best for: Fiberglass synthetic casting, waterproof cast systems. Confirm compatibility with casting tape manufacturer IFU.

Property	Cotton	Synthetic
Self-cohesion	Yes — fibres bond to themselves, no slipping	Variable — some synthetic products are cohesive, others less so
Featherability at edges	Excellent — fibres pull apart for smooth tapered edges	Limited — non-woven structure does not feather as smoothly
Absorbency	High — absorbs perspiration and wound drainage	Lower — wicks moisture but less absorption capacity
Loft (cushioning per layer)	Moderate	Higher — more cushioning per unit weight
Thickness consistency	May thin at bony prominences with wear	More consistent thickness maintained during wear
Casting system compatibility	Preferred for POP; suitable for fiberglass	Preferred for synthetic fiberglass casts — confirm IFU
Cost	Lower	Higher
Source	BSN Medical Specialist 100, Dukal, Cardinal Health Webril product documentation

Section 03

The Feathering Technique: Why It Matters for Procurement

Feathering is a casting technique where the edge of each overlapping layer of undercast padding is thinned by pulling the fibres apart, creating a tapered transition rather than a blunt fold edge. This is a fundamental skill in plaster room practice — and the featherability of the cotton padding is a key quality criterion that procurement managers should evaluate.

Why feathering matters clinically

When undercast padding is applied in overlapping spiral layers, each overlapping edge creates a double-thickness band if not feathered. When the cast material is applied over these doubled bands, they become embedded in the hardened cast as internal ridges. These ridges create focal pressure against the skin during extended cast wear — potentially causing pain and pressure sores that can go undetected until the cast is removed.

The quality criterion for procurement

Cotton padding that feathers well has loosely twisted fibres that can be separated gradually at the edge, creating a smooth taper from full thickness to near-zero. Cotton padding that feathers poorly — either because the fibres are too tightly bound or because the product tears abruptly rather than tapering — produces ridged cast interiors even when correctly applied.

How to evaluate featherability before purchasing

Request product samples before committing to a new supplier. Test featherability: hold the padding roll and pull apart the fibres at the edge with your fingertips. Good-quality cotton padding should thin gradually and evenly — the edge should taper over 3–5 cm. Poor-quality padding tears abruptly at or near the edge without tapering. This simple test distinguishes quality cotton padding from lower-grade alternatives more reliably than comparing datasheets alone. Source: BSN Medical Specialist 100 product documentation describes "tears and feathers easily" as a primary quality feature.

Section 04

Bony Prominence Protection: A Procurement Consideration

Standard cast padding technique applies 2–3 overlapping spiral layers over the entire limb. This provides baseline cushioning. Bony prominences — areas of elevated pressure risk under the cast — require additional padding before the spiral layers are applied.

Common bony prominences requiring extra padding in orthopaedic casting:

Lower limb: medial and lateral malleoli (inner and outer ankle), tibial crest (shinbone front), heel, fibular head (outer knee)
Upper limb: radial and ulnar styloids (wrist), olecranon (elbow), radial head (outer elbow), ulnar border (inner forearm)
Any prominent bony area within the cast that is not covered by adequate soft tissue

Procurement implication: stock narrow widths for bony prominence padding

Extra local padding over bony prominences is applied before the standard spiral layers. A narrow roll (5 cm or 7.5 cm) is easier to apply accurately over a small bony area than a full-width roll. Most plaster room procurement focuses on the main working widths (10 cm, 15 cm) without specifically stocking narrow rolls for prominence padding. Including 5 cm and 7.5 cm rolls in procurement ensures the technique can be correctly performed for all patient sizes and cast types.

Section 05

Standard Specifications

Undercast padding — specification reference

Material (cotton)100% cotton or cotton/viscose blend — self-cohesive, featherable, hand-tearable

Material (synthetic)Non-woven polyester — high loft, moisture-wicking, conformable

Standard widths5 / 7.5 / 10 / 15 / 20 cm — source: Henso Medical product spec

Standard weights75 / 80 / 90 g/m² — source: Henso Medical product spec

Standard roll length (metric)2.7 m or 3 m per roll — source: Henso Medical product spec

Standard roll length (North American)4 yards (approx. 3.65 m) — source: Cardinal Health Webril, BSN Sof-Rol product specs

Application method2–3 overlapping spiral layers at approx. 50% overlap; edge feathered on each layer

SterilityNon-sterile (standard for casting); sterile available on request

Latex contentLatex-free — written declaration available

RegulatoryCE (EU MDR 2017/745 Class I) · ISO 13485 · FDA registered · SFDA registration support for GCC supply

Section 06

Width Selection for Orthopaedic Department Procurement

Width	Primary applications	Notes
5 cm (2")	Fingers, toes, bony prominence spot-padding	Stock specifically for bony prominence extra-padding technique and small extremity casting
7.5 cm (3")	Wrist, small forearm, paediatric limbs, bony prominence padding	Short arm casts, paediatric casting, ulnar/radial styloid prominence padding
10 cm (4") ★	General adult forearm, ankle, lower leg	Most commonly procured. Long and short arm casts, below-knee casts. Highest volume consumption.
15 cm (6")	Knee, upper arm, thigh	Long leg casts, cylinder casts, above-knee casts
20 cm (8")	Large thigh, trunk	Body casts, very large limbs

Section 07

Procurement Specification Checklist

Specify material — cotton (POP/general casting) or synthetic (fiberglass/waterproof) — confirm with your casting tape manufacturer's IFU which padding material is recommended for your casting system. Cotton is the default for POP; synthetic is preferred for waterproof fiberglass systems
Request product samples and test featherability before committing to a new supplier — pull the edge fibres of the sample apart to assess how smoothly and gradually the padding tapers. Abrupt tearing without tapering indicates poor featherability. This is the single most useful quality test for cotton undercast padding
Specify weight — 75, 80, or 90 g/m² based on clinical need — lower weight for thinner, less bulky padding under close-fitting casts; higher weight where more cushioning is required. Confirm the weight in g/m² with the supplier — "standard" is not a weight specification
Specify widths to cover full clinical range including narrow sizes for bony prominence work — procure 5 cm or 7.5 cm alongside standard 10 cm and 15 cm rolls to enable correct bony prominence extra-padding technique without improvising with oversized rolls
Confirm hand-tearable without scissors — hand-tearability is standard for cotton and most synthetic padding. Essential for plaster room workflow — if the padding requires scissors to cut, application speed and accuracy are compromised
Confirm latex-free and request written declaration — undercast padding is in prolonged contact with patient skin under the cast. Latex-free written confirmation required for facilities with latex-sensitive patient protocols
Verify CE marking and confirm SFDA registration for GCC supply — CE Class I under EU MDR 2017/745. SFDA registration required for Saudi Arabia institutional supply

Data Sources

BSN Medical. Specialist® 100 Cotton Undercast Padding. "100% cotton. Self-cohesive. Tears and feathers easily — ideal for creating custom padding for joints or bony prominences. Highly absorbent. Hand tearable." cmecorp.com/bsn-medical-specialist-100-cotton-undercast-padding.
BSN Medical. Protouch Synthetic Cast Padding. "Soft synthetic material provides excellent padding. Consistent thickness ensures even protection. Moisture-wicking synthetic fibers keep skin dry." orthotape.com.
Dukal Corporation. Undercast Padding. "Cotton fiber construction can be teared easily and ensures good absorbency. A non-woven polyester padding that is porous, highly conformable, and strong yet easy to tear." thomassci.com.
Henso Medical. Orthopaedic Cast Padding product specification. Widths: 5cm/7.5cm/10cm/15cm/20cm. Weights: 75/80/90 g/m². Lengths: 2.7m/3m. Material: 100% cotton or viscose, polyester. hensomed.com/products/orthopedic-cast-padding/.
Cardinal Health. Webril Cotton Undercast Padding. Standard format 4" × 4 yards confirmed across multiple product listings. wilburnmedicalusa.com.

Related guides

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Sourcing undercast padding for orthopaedic or distributor supply?

Kingphar manufactures cotton and synthetic undercast padding in widths 5–20 cm, weights 75–90 g/m², rolls 2.7–3 m — CE-certified under EU MDR 2017/745, ISO 13485, with SFDA registration support and Arabic labeling for GCC institutional supply.

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