Tests in which women in high-heels walked along a platform fitted with special sensors showed that their knees were put under sufficient strain to produce the wear and tear which leads to osteoarthritis.

The area of greatest stress was on the inner side of the knee joint - where arthritis is most commonly seen.

Osteoarthritis of the knee is twice as common in women as it is in men - and the researchers suggested in an article in The Lancet medical journal that high heels might be the reason why.

The study was carried out by Dr Casey Kerrigan and colleagues at Spaulding Rehabilitation Hospital and Harvard Medical School in Boston, Massachusetts, USA.

They asked 20 healthy women with an average age of 36 to walk along a special platform in bare feet and then in shoes with two-and-a-half inch heels.

Sensors under the platform, and cameras, recorded the movements of the women's ankle and knee joints.

Strain on knees

The results showed that when the women were walking in high heels there was greater strain between the kneecap and thigh bone and in the inner side of the knee joint than when they walked with bare feet.

Walking in high heels increased the normal torque forces at the knee by an average of 23%, which imposed a greater stretching force through the lateral knee ligaments.

The researchers pointed out that animal experiments had shown increased strain of this kind led to degenerative changes.

They write: "Our findings confirm that wearing high-heeled shoes significantly alters the normal function of the ankle. Because of this compromise, compensations must occur at the knee and hip to maintain stability and progression during walking. Our findings suggest that most of these compensations occur at the knee."

The doctors said the possibility that high-heeled shoes may contribute to osteoarthritis had not been proposed to date.