People with hip and knee osteoarthritis are often advised to choose “appropriate footwear” to minimise pain, but the best choice isn’t necessarily what many believe. New research, including a clinical trial published today in Annals of Internal Medicine, suggests that stable, supportive shoes aren’t always the optimal solution.
Osteoarthritis, a condition affecting the tissues in and around a joint – including bone, cartilage, ligaments, and muscles – is a growing concern, particularly among aging populations and those with higher body weights. It causes joint pain and stiffness, potentially leading to disability. An estimated 2.35 million Australians currently live with osteoarthritis, a number projected to rise with demographic shifts and increasing obesity rates, according to recent data.
The condition commonly affects the hip and knee, making walking difficult. Even as there is currently no cure, self-management strategies are crucial. One frequently discussed aspect of self-management is footwear.
Shoes act as the primary connection between the body and the ground, influencing how forces are transmitted through the leg with each step. Features like heel height and sole stiffness are thought to play a significant role. Shoes with high heels, for example, can substantially increase joint forces; a six-centimetre heel increases knee forces by an average of 23% compared to barefoot walking. Supportive features, such as arch-supporting insoles or stiffer soles, are often recommended, based on the assumption they provide stability and reduce stress on the joints.
But, biomechanical research challenges this conventional wisdom. Studies have shown that shoes with these supportive features can actually increase knee force by up to 15% compared to shoes without them. Arch-supporting insoles can also increase knee force, by as much as 6%.
This raises the question: are flatter, more flexible shoes – like ballet flats – a better option for those with hip and knee osteoarthritis? The answer, researchers have found, is not straightforward.
Previous biomechanical research conducted in 2017 demonstrated that flat, flexible shoes reduced knee forces by an average of 9% compared to stable, supportive styles. To investigate whether this translated to pain relief, researchers conducted two clinical trials.
The latest trial, involving 120 people with hip osteoarthritis, randomised participants to wear either flat, flexible shoes (such as flexible ballet flats) or stable, supportive shoes (such as supportive runners) for at least six hours a day. After six months, researchers measured changes in hip pain during walking. The results showed no significant difference in hip pain between the two groups.
These findings contrast with a 2021 clinical trial involving 164 people with knee osteoarthritis. That trial revealed that wearing stable, supportive shoes for six months reduced knee pain during walking by an average of 63% more than wearing flat, flexible shoes.
Researchers suggest the differing outcomes may be due to the higher joint forces experienced in knee osteoarthritis compared to hip osteoarthritis, potentially making the knee more responsive to the force-reducing effects of stable supportive shoes.
Notably, both trials reported a higher incidence of complications, such as foot pain, among those wearing flat, flexible shoes, potentially due to the lack of protection these styles offer.
Based on these findings, stable supportive shoes appear to be more beneficial for individuals with knee osteoarthritis. For those with hip osteoarthritis, neither shoe type demonstrated a clear advantage in reducing hip pain. However, all older adults – including those with hip or knee osteoarthritis – should avoid ill-fitting shoes and those with high or narrow heels to minimise the risk of falls.
For younger individuals with knee or hip osteoarthritis who are not at high risk of falls, avoiding high heels may still be advisable given their potential to increase joint forces. Individuals concerned about their hip or knee osteoarthritis are encouraged to consult with their general practitioner or other healthcare providers, such as podiatrists or physiotherapists. Other non-surgical treatments, including exercise, weight management, nutrition, and pain medication, can also play a role in managing the condition.
