"Killer heels could lead to osteoarthritis in knees," The Daily Telegraph reports. An analysis of the walking patterns (gait) of 14 women found evidence that walking in high heels puts the knees under additional strain. Over time, this may potentially lead to osteoarthritis: so-called wear and tear arthritis, where damage to a joint causes stiffness and pain.
The main finding was that wearing high heels (3.8cm and 8.3cm were tested) changed the walking gait, especially around the knee joint area.
Hypothetically, the changes in knee dynamics seen in this study could potentially cause strain on the joint, damaging the cartilage inside the knee, thus increasing the possibility of knee osteoarthritis in later life.
However, the study did not keep in touch with participants to see if they went on to develop arthritis, so doesn't prove any direct evidence that wearing high heels causes more knee osteoarthritis further down the line.
There are many factors linked to developing osteoarthritis in later life, most notably obesity, joint injuries and repetitive stress. Based on this study alone, it is not clear whether footwear is an important additional factor in the mix.
That said, we suspect that wearing high-heels all day, seven days a week, won't do wonders for your feet.
Where did the story come from?
The study was carried out by researchers from Stanford University Medical Center (US) and was funded by the National Institutes for Health.
The study was published in the peer-reviewed medical journal the Journal of Orthopaedic Research.
The UK's media reporting was factually accurate, although did not highlight any of the limitations of the research. Coverage tended to assume that the study had found a causal link between heel height and osteoarthritis in later life, which was not the case.
What kind of research was this?
The research team outline that knee osteoarthritis is about twice as prevalent in women as men and that wearing high-heeled shoes might be contributing to the higher risk in women.
This was an experimental study examining whether high-heeled walking, with and without additional weight, produces gait changes similar to those associated with increased risk of knee osteoarthritis.
The team were testing two theories.
Firstly, that there are significant changes to knee movement and forces during walking that increase in magnitude as heel height increases; and secondly, that the changes to knee movement during walking in high heels are made more extreme by a 20% increase in weight.
The study was set up to tell us whether women walk differently with heels and with added weight. It was not designed to prove that any change would cause more knee damage, specifically osteoarthritis in the future, but this was the research team's working assumption.
What did the research involve?
The research involved 14 healthy female volunteers whose walking pattern - called their gait - was analysed while wearing different footwear. They were comparing "flat athletic shoes" - presumably trainers - with high heels of various heights, 3.8cm (1.5inches) and 8.3cm (3.2 inches). Each participant underwent measurements nine times in total for each shoe. This included walking at three different speeds.
A second part of the study was looking at whether adding weight to the person affected their walking pattern still further. They achieved this by studying the women's gait with and without them wearing a vest that added 20% to their total body weight. Women with the added weight were tested wearing the different footwear.
The study analysis compared the gait parameters between the different footwear and for the added weight, to look for changes to the women's normal walking style.
The authors were aware that walking speed affects measures of walking pattern, so performed additional analysis to account for potential differences in walking speed.
What were the basic results?
The bottom line was that there were some significant walking pattern changes linked to the two heel heights tested, and the 20% extra weight. For example, when wearing heels, women tended to bend their knees more during specific phases of their walk.
Women walked slower in heels, but weight did not affect walking speed.
How did the researchers interpret the results?
The researchers said that "Many of the changes observed with increasing heel height and weight were similar to those seen with ageing and OA [osteoarthritis] progression," and that, "This suggests that high heel use, especially in combination with additional weight, may contribute to increased OA risk in women."
The main finding of this study was that wearing high heels affected the way women walk compared to flat shoes. Although not a surprise, the study's findings could still be unreliable, as it involved only 14 women. A study of more people would improve confidence in the findings.
The issue that grabbed the headlines was the possibility that this might lead to a higher risk of knee osteoarthritis later in life.
While the study authors do say that "Many of the changes observed with increasing heel height and weight were similar to those seen with ageing and OA [osteoarthritis] progression", this does not prove cause and effect. The study itself does not provide evidence on whether heels actually cause an increase in joint disease or any kind, only that they affect the way women walk. Other factors, such as how often the women wear heels, what height, at what age they start and stop wearing them and many other factors, could also influence any association between footwear and joint problems in later life.
There is potentially a different way of assessing the theory that heels may be related to different prevalence of knee osteoarthritis in men and women in later life. You could study knee osteoarthritis rates in men who regularly wear high heels (for example, transvestites and panto performers) to see if they have similar rates of osteoarthritis to similar heel wearers who are women.
Overall, this small study gives researchers more information on the precise gait changes that occur when a woman wears heels, or when they carry added weight. However, the study does not contribute any further understanding about whether wearing heels is causally related to joint problems in later life.
However, there have been reports of an association between "over-wearing" high heels and foot problems such as corns and calluses. Most foot care specialists would recommend saving your killer heels for special occasions, and sticking to flats or trainers for the daily commute. Read more advice about foot care.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.
"Killer heels could lead to osteoarthritis in knees," The Daily Telegraph reports. An analysis of the walking patterns of 14 women found evidence that walking in high heels puts the knees under additional strain, which could damage cartilage.
Links to Headlines
Killer heels could lead to osteoarthritis in knees, warn scientists. The Daily Telegraph, January 14 2015
Links to Science
Titchenal MR, Asay JL, Favre J, et al. Effects of high heel wear and increased weight on the knee during walking. Journal of Orthopaedic Research. Published online December 22 2014
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