Modern hip replacements go back almost 40 years and are the most common joint replacement surgery performed, and yet until researchers decided to investigate earlier this year, nobody had taken the trouble to figure out how men and women can have sex after hip surgery without worrying about the risks.
Just how much range of motion does sexual activity involve – and which specific types of activity can dislocate an artificial hip?
That’s what a team of Swiss-based computer and medical scientists decided to find out, using a motion capture technology – a way of recording real people’s complex movements that’s often used in creating 2- and 3D computer animation. In this case, the team used a pair of human volunteers, a man and a woman.
If the lithe figures in the motion-capture diagram above don’t remind you of you, that may be because the volunteers who were used for this project are much younger – despite the fact that the majority of hip replacements are still performed on older people. Still, hip surgery among active middle-agers has almost doubled in the past decade, leading doctors to pay more attention to sex. As Dr. Charles Cornell at New York’s Hospital for Special Surgery told the Times: “It’s especially important to our younger patients, but believe it or not, I’ve had patients in their 80s who this has been a topic for.”
In their recently published paper, “Sexual Activity after Total Hip Arthroplasty,” the Swiss team concludes that sexual positions for women require an intensive range of hip motion, whereas positions for men are fairly risk-free. They asked their volunteers to try 12 common positions and noted that four positions – the ones with the X in the diagram above – require intensive flexion for women and can cause an impingement. A check mark next to a position in the diagram means that it is safe.