What does "orthopaedic mattress" actually mean? Less than you think

If you have a sore back and you have started looking at mattresses, you will have seen the word on half the boxes: orthopaedic. It sounds medical. It sounds like someone has checked. Here is what it actually means, why we do not use it, and what to look for instead if a bad back is why you are shopping.

There is no definition

"Orthopaedic" is not a grade, a certification or a standard. No British Standard defines it, no medical body awards it, and no test has to be passed to print it on a label. Any manufacturer can call any mattress orthopaedic, and many do. It is a marketing word from the 1960s that stuck because it sounds like a doctor said it.

In practice, when a UK retailer calls a mattress orthopaedic, they mean one thing: it is firm. Often very firm. Sometimes it is an open-coil unit with a thin layer of firm foam and a hard hand-feel, at the cheapest end of the range, with the word doing the work the build does not.

Firm is usually the wrong answer

This is the part that matters. The best evidence on mattresses and low back pain does not favour hard mattresses. The one properly run trial, published in The Lancet in 2003, gave 313 people with chronic low back pain either a firm or a medium-firm mattress for three months. The medium-firm group did better: less pain in bed, less pain getting up, less disability. Smaller studies since have pointed the same way.

The reason is simple. On a hard mattress your shoulders and hips cannot sink at all, so your waist hangs unsupported and your spine bends towards the bed. On your back, your lower back arches over a gap. You wake stiff and you toss all night looking for a position that does not ache. A medium-firm mattress with a real comfort layer lets the wide parts settle and holds the narrow parts up, which is what "support" actually means.

So a mattress sold as orthopaedic, meaning hard, is often the one most likely to make a sore back worse. That is why we do not use the word on anything we make. If you have ongoing pain, see a professional; a mattress supports you, it does not treat you.

What people searching for "orthopaedic" actually want

When someone types the word, they are not asking for a standard. They are asking for a mattress that will not sag, will hold their back level, and will not feel like a hammock in three years. Those are real things and they have real names:

• Zoned springs. A spring unit where the centre third, under your hips and lower back, is firmer than the shoulder area, so your hips do not sink lower than your shoulders when you lie on your side. Look for "3-zone" or "5-zone".
• A proper comfort layer. Around 4 to 6 cm of pressure-relieving material on top: memory foam of 55 kg/m³ or more, or latex. Less than 3 cm over a firm spring unit is a hard mattress with a blanket on it.
• Foam density you can see. Support foams of 40 kg/m³ and up and memory foam of 55 and up stay level for eight to ten years. Foams under 40 dish in three, whatever the label says.
• A firm edge. A steel rod or a dense foam rail, so the side does not collapse when you sit on it to get up. Edge collapse is where "my orthopaedic mattress has gone soft" usually starts.
• A choice of tension. Medium for most people; Firm for heavier builds and front sleepers. The traditional makers have always sold mattresses this way, and it is the honest version of "firm or not".
• A base that is not the problem. Slats over 7 cm apart or a tired divan will make any mattress feel wrong.

The questions to ask any seller

1. What is the density, in kg/m³, of each foam layer? ("High density" is not a number.)
2. Are the springs zoned, and how?
3. What is the wire gauge of the spring unit?
4. What holds the edge up?
5. Is this medium-firm or firm, on a scale where ten is a board?

A maker who specifies the mattress will answer all five in a sentence each. A seller who says "it's orthopaedic" and stops there has told you what you needed to know.

How we built ours

The Bad Back Years is what most people are looking for when they search the word, without the word. It is medium-firm on purpose: 2,000 pocket springs in five zones with a firmer centre third, 5 cm of 60 kg/m³ memory foam for pressure relief, a steel edge, and Medium or Firm tension at no charge, with split tension in king sizes for couples who differ. Every layer and density is on the page. If it is too soft for you after 30 nights, we swap it.

The short version

• "Orthopaedic" has no standard, no test and no definition. It usually means hard.
• The evidence favours medium-firm for sore backs, not hard.
• What you actually want: zoned springs, a real comfort layer, published densities, a firm edge, a tension choice, a sound base.
• Ask for numbers. A seller who has them will give them.