Types of Compression Therapy Explained

Compression works on a simple principle. Pressure applied at the ankle, decreasing as it moves up the leg, helps the calf muscle pump push blood and lymph upward instead of letting it pool. That gradient — highest at the bottom — is what makes medical compression different from a tight sock.

What follows is the practical map: what the classes mean, what forms compression comes in, and which situation calls for which.

Compression classes

Classes are defined by the pressure delivered at the ankle, measured in millimetres of mercury. Higher is not better — it is simply stronger, and the right class depends on the diagnosis and on the arterial supply.

• Class I (light) — mild aching and swelling, early varicose veins, long journeys, prolonged standing at work
• Class II (medium) — symptomatic varicose veins, after endovenous ablation or surgery, and after deep vein thrombosis
• Class III (strong) — severe chronic venous insufficiency, healed venous ulcers and established lymphoedema

Class numbering differs between national standards, so a “Class II” garment from one system is not identical to another. This is one reason to have compression prescribed rather than picked from a shelf.

The forms compression takes

Graduated compression stockings

The everyday workhorse: knee-length in most cases, thigh-length or pantyhose where swelling extends higher. Knee-length garments are worn more consistently, and consistency matters more than theoretical coverage.

Multilayer compression bandaging

Applied by trained staff and left in place for several days at a time, this is the standard for active venous leg ulcers and for the intensive reduction phase of lymphoedema, where limb size changes too fast for a fitted garment.

Adjustable wrap devices

Velcro wraps that the patient tightens themselves. Valuable where hand strength, arthritis or limb shape makes pulling on a stocking impractical — a common reason compression gets abandoned.

Intermittent pneumatic compression

A pump inflates chambers in sequence along the limb to assist venous and lymphatic return. Used as an adjunct to garments, particularly in lymphoedema and in immobile patients.

Getting it to actually work

• Put stockings on before getting out of bed, while the leg is at its smallest, and remove them at night unless told otherwise
• Have the limb measured rather than sized by shoe or dress size
• Use rubber gloves or a donning aid — most “it does not fit” complaints are application problems
• Replace garments every three to six months; elasticity is lost with washing and wear
• Moisturise at night, not before putting the garment on
• Remove it and seek review if toes become numb, blue or white, or pain increases

A garment that has become easy to pull on is no longer delivering its rated pressure. That is the single most common reason compression quietly stops working.