People with hip and knee osteoarthritis are advised to wear “appropriate footwear” to minimise their pain.

Does that mean heels are out? Does it matter if you wear runners or something a little stiffer? How about using insoles?

Our research, including our latest clinical trial published today in Annals of Internal Medicine, provides some answers.

We show that stable, more supportive shoes aren’t necessarily the best option, despite what you might have heard.

What is osteoarthritis?

Osteoarthritis is a condition that affects the tissues in and around a joint, including bone, cartilage, ligaments and muscles. It is more common in older people, and people with excess body weight. It causes joint pain and stiffness, and can lead to disability.

About 2.35 million Australians have osteoarthritis and this number is predicted to increase as the population ages and obesity rates rise.

Osteoarthritis commonly affects the hip and knee joints, making it difficult to walk. There is no cure, so self-management is important.

That includes wearing the right type of shoes.

How can shoes affect symptoms?

There are many causes of osteoarthritis, but excessive force inside the joint when someone is walking is thought to play a role. Excessive joint forces can also increase the chance of osteoarthritis worsening over time.

Shoes are our connection to the ground and can influence how forces are transmitted up the leg during every step. Some shoe features are particularly important.

Shoes with higher heels increase joint forces. For example, shoes with six-centimetre heels increase knee forces by an average 23% compared to walking barefoot.

Some shoes come with supportive features, such as insoles that support the arches. Other supportive features include being made with a stiffer material in the sole or heel.

Many people, and clinicians, think these stable and supportive shoe features are best for people with osteoarthritis.

But biomechanical research shows shoes with these supportive features actually increase knee force by up to 15% compared to shoes without them. Arch-supporting insoles also increase knee force by up to 6% when added to shoes.

So, are flatter, flexible shoes without stable supportive features – such as ballet flats – better for knee and hip osteoarthritis?

Not necessarily. We also need to look at people’s pain.

What we found

Our biomechanical research from 2017 in people with knee osteoarthritis showed flat flexible shoes reduced knee forces by an average 9% compared to stable supportive shoe styles.

This suggests flat flexible shoes could be better for osteoarthritis. To find out, we conducted two clinical trials to look at people’s pain levels.

Our new clinical trial involved 120 people with hip osteoarthritis.

They were randomised to wear different types of flat flexible shoes, such as flexible ballet flats, or different types of stable supportive shoes, such as supportive runners. People were asked to wear their shoes for at least six hours a day. After six months we measured the change in hip pain when they walked.

We found flat flexible shoes were no better than stable supportive shoes for reducing hip pain.

These findings differ to those from our 2021 clinical trial in 164 people with knee osteoarthritis. In that trial, we found wearing stable supportive shoes for six months reduced knee pain when walking by an average 63% more than wearing flat flexible shoes.

It’s unclear why findings differed between the knee and hip. But it might be because joint forces are higher in knee compared to hip osteoarthritis, and so there may be greater potential for stable supportive shoes to reduce knee forces, and therefore knee pain.

In both trials, more complications, such as foot pain, were reported by people who wore flat flexible shoes. This might be because these shoe styles provide less protection for the feet.

So which shoes should I wear?

For people with knee osteoarthritis, stable supportive shoes are likely to be more beneficial than flat flexible ones.

For people with hip osteoarthritis, neither shoe type is better than the other for improving hip pain.

But for all older people – including those with hip and knee osteoarthritis – it is sensible to avoid ill-fitting shoes, as well as shoes with high or narrow heels, due to an increased risk of falls.

For younger people with knee or hip osteoarthritis but who are not at risk of falls, it may still be advisable to avoid high heels given their potential to increase joint forces.

Who should you talk to?

If you are concerned about your hip or knee osteoarthritis, talk to your GP or other health-care provider, such as a podiatrist or physiotherapist.

Other non-surgical treatments, such as exercise, weight management, nutrition and some pain medicines can help.

Kade Paterson, Associate Professor of Musculoskeletal Health, The University of Melbourne and Rana Hinman, Professor in Physiotherapy, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.