NEW YORK - "Manly" hands might signal an increased risk of suffering a knee injury, if one study is correct.

The study, which targeted more than 1,000 middle-aged and older US adults and was published in Arthritis & Rheumatism, found a higher risk of knee injuries among men with a bigger discrepancy in the lengths of their index and ring fingers.

In general, men tend to have relatively short index fingers and longer ring fingers, while women show more equality in those two digits. A greater difference between the two fingers, whether in a man or a woman, is thought to reflect greater exposure to testosterone in the womb.

Ida Haugen of Diakonhjemmet Hospital in Oslo, Norway, and her team analyzed data on 1,020 US adults aged 51 to 92 in Framingham, Massachusetts, focusing on their history of knee injuries and arthritis symptoms. They also looked at x-rays of subjects' hands and knees.

Overall, 28 percent of men and 23 percent of women said they'd had a knee injury that kept them off their feet for at least a few days.  

The odds of having such an injury were 78 percent higher among the one-third of men with the biggest finger-length disparity, versus the one-third with the smallest discrepancy.

There was no link between finger length and knee injuries among women, nor was there a relationship between finger length and knee arthritis is men or women.

Some studies have linked the "male" finger pattern to higher aggression levels and athletic prowess, while others have tied the pattern to certain health conditions, including arthritis in the knee and hand.

No one knows why those links exist, but one theory is that early testosterone exposure is at play

The cartilage that cushions the joints is sensitive to testosterone, so it's possible that greater exposure to the hormone somehow makes the tissue more vulnerable to damage, wrote Haugen.

Since the finger pattern has been tied to aggression and sports skills, it's also possible that men with the pattern are more likely to be in situations where they could be injured.

So, should men with long ring fingers worry about their knees?

Probably not, researchers said. The risk of any one person suffering a knee injury or arthritis would depend much more on factors like age, physical activity and body weight.