Boomers saw man walk on the moon. Of course they want bionic knees.

As this generation ages, spending on health upgrades like custom joint replacements, bone-building drugs, and wrinkle creams could reach trillions.

Illustration by Kevin Whipple

Baby boomers were reared on the television fantasy of Steve Austin, the Six Million Dollar Man, an astronaut critically injured when his aircraft crashed, then re-engineered to superhuman speed and strength by bionic implants. He went off the air in 1978. Today, boomers are on the verge of being able to heal their ills in ways he couldn’t even imagine. They won’t just battle the hazards of aging, they’ll delay and even avoid them. Potential spending on upgrades like custom-built knees, bone-building drugs, and wrinkle-fighting skin polymers could reach trillions of dollars.

The knees are already available, and many other breakthroughs are close. Sheer demand should bring still more to the marketplace. And why not? “This is the generation that saw a landing on the moon, the ATM machine, and the personal computer,” says Joe Coughlin, director of the Massachusetts Institute of Technology’s AgeLab. “Do we really expect that people who have seen these kinds of transformations aren’t going to demand new knees?”

Artificial knees and hips have been around for a while. But so have complaints about complications, botched operations, and the need for second surgeries. All knees may be knobby, but they vary widely in shape and size, even between a person’s left knee and right knee. So off-the-shelf joint implants have obvious limitations when it comes to fit. Companies like Bedford’s ConforMIS Inc. are changing the game by using imaging software and 3-D printing to tailor knee replacements for each patient. Taking an image of the knee, then creating a precisely tailored replacement part using a 3-D printer, means less potential for a new knee to form a painful overhang or underhang on the bone. It’s the same personalization phenomenon that genetics is creating in medicine, says Adam Hayden, senior vice president at ConforMIS.

The parts for custom knees and the tools needed to implant them are prepared before surgery; the actual operation can take as little as 70 minutes, says Dr. Joseph Czarnecki, an orthopedic surgeon at Winchester Hospital. He’s replaced close to 250 knees with ConforMIS models over the past three years. Patients and their new knees can sometimes be discharged the same day, though they typically spend a night or two recuperating.

The knees, Czarnecki says, “are a better mousetrap,” but, unlike Steve Austin’s bionic upgrades, they are still not quite as good as the real thing. The big issue, he says, remains that “you can’t run on them.” What we do gain from these new joints is something nearer to our natural gait than the off-the-shelf implants, because the custom ones get closer to the natural curve of the knee where it sits at the end of the femur. Meanwhile, work is underway to customize hips, shoulders, and ankles — all body parts that can make our lives disjointed as we age.

And boomers are counting on technology to solve other problems. “Our parents and grandparents aged politely and quietly,” Coughlin says. “They expected that their knees would creak and they would spend more time at home and hope the grandchildren visited. The baby boomers have never been quiet.” They came of age, after all, drowning out the Beatles during concerts and letting it all hang out at Woodstock. Now they shell out huge amounts for reunion tours, and hearing aids are a real downer. Today, scientists are experimenting with growth factors — natural stimulants like hormones and vitamins — to repair damaged hearing. Also being tested are “second skin” polymers to banish wrinkles from too much fun in the sun, gene therapies to restore lost vision, and drugs to slow the progression of dementia.

Illustration by Kevin Whipple

Scientists are also tackling osteoporosis, where bones break down faster than they can rebuild (mostly in women). About 10 million Americans have it and 44 million face high risk of getting the condition, caused by hormonal changes or calcium deficiency, which can make bones so brittle that bending over or coughing can result in fractures. Waltham biotech Radius Health Inc. has developed bone-building hormones to treat osteoporosis, boosting bone mineral density by stimulating new bone formation. US regulators are considering it for approval. Right now, the drug has to be injected, though Radius scientists are working on a transdermal patch that would deliver it through the skin. And when early diagnosis of osteoporosis becomes more common, doctors could prescribe bone-building therapies to prevent fractures, says Radius chief executive Bob Ward.

He says that as doctors more widely use bone mineral density tests to see whether patients are likely to develop severe osteoporosis, they will also get better at targeting treatment regimens for them. Separately, the company is working on a drug that would treat hot flashes in menopausal women, which could be available within five years.

Steve Austin was “born” in 1942, when men’s life expectancy in the United States was 65, women’s 68, in part because of killers like heart disease. Boomers, by contrast, are expected to live into their mid-80s. That’s in part because they smoke less than previous generations. But it’s also because medical science has staved off big killers like heart disease and strokes with statins and blood pressure pills that make these conditions much more manageable. Some cancers previously viewed as death sentences now are seen as setbacks, thanks to other new treatments.

Since the first artificial heart was implanted in 1982, cardiac care has also seen huge advances. Locally, companies like Abiomed Inc. of Danvers and Mitralign Inc. of Tewksbury are rolling out new high-tech products and techniques. Abiomed’s heart pumps, delivered through a catheter, replace inflatable balloon pumps to help weakened hearts circulate more blood with less work. Mitralign’s devices enable doctors to repair some leaky valves that were formerly out of reach. Both should help patients avoid open-heart surgery, which remains risky and expensive. Meanwhile, for the more than 700,000 Americans who suffer heart attacks each year, scientists are working on technology to replace the resulting scar tissue, which reduces the efficiency of the heart.

The Karp Lab in Cambridge has licensed technology to Gecko Biomedical, a French company, which is developing sealants and tissue-engineered patches to help replace sutures and staples. The technologies, in combination with others, could also eventually regenerate healthy tissue, including in heart attack victims. The company is starting a clinical trial in Europe this year and another in the United States next year, using a “glue” made of glycerol and sebacic acid, both of which exist naturally in the body, during vein graft procedures. These tissue experiments will be useful for more than the baby boomer generation; many tissues can’t regenerate even in young people. Scientists are looking at new ways to stimulate tissue generation in the body or to build replacement tissues.

Illustration by Kevin Whipple

Karp Lab has also partnered with MIT professor Bob Langer on a treatment that could restart the growth of hair cells in the inner ear to restore lost hearing. Smoking, diabetes, or prolonged exposure to loud noise can damage these hair cells, leading to hearing loss. “Hopefully we can provide cues for the cells to grow [back], for the body to grow its natural structure,” says Langer, whose MIT lab has launched dozens of life sciences startups.

Langer and Karp founded Frequency Therapeutics, a Cambridge startup still in stealth mode, led by serial entrepreneur David Lucchino. It is examining different approaches to regenerating hair cells and eliminating the need for those dreaded hearing aids. One approach would be squirting a small molecule drug they discovered into the ear to see if it will improve hearing naturally. The goal is to make organs work as well at age 75 as they do at age 30. Taking a different tack, another early-stage biotech, Decibel Therapeutics of Cambridge, is seeking to reverse hearing loss by repairing broken connections between sensory cells and nerve fibers in the inner ear.

And then there’s the problem of failing eyesight. Who wouldn’t prefer just to skip macular degeneration, some forms of which are caused by a decaying gene? Scientists are exploring ways to replace this gene with a healthy one. Right now, most gene therapies are being tested on conditions that afflict younger people, says Jeffrey Marrazzo, chief executive of Spark Therapeutics Inc. The Philadelphia company will seek FDA approval this year to treat a rare inherited retinal disease that can cause blindness. If the early gene therapies prove out, Marrazzo says, expect scientists at other biotech companies to look at how to reverse more common vision-loss conditions.

Perhaps the most feared side effects of living longer are brain disorders like Alzheimer’s disease. For now there are few effective remedies, but Cambridge’s Biogen Inc. is in clinical tests of a drug that may reduce the buildup of amyloid plaque in the brain, suspected as a key factor in the progression of Alzheimer’s. Biogen is just one of a number of biopharma companies trying to stem the neurodegenerative disease, which affects tens of millions worldwide.

Meanwhile, scientists at the Institute for Aging Research at Albert Einstein College of Medicine in New York are planning to test a common diabetes pill, metformin, that some have called a “fountain of youth” treatment with potential to fend off cancers, heart ailments, and cognitive decline. They aren’t the only Ponce de Leons out there. Elysium Health of New York, founded by MIT biologist Leonard Guarente, is marketing an anti-aging vitamin that it claims helps the body produce a natural compound to restore muscle tissue, improve brain function, and boost energy levels. And scientists at MIT and Massachusetts General Hospital spent more than five years developing an experimental “second skin,” a silicone-based polymer coated over aging skin to smooth out wrinkles and restore elasticity. The  scientists created two companies to try to commercialize the research. One is looking at applying it to skin conditions like dermatitis. The other is exploring uses like reshaping those bags under the eyes and even offering protection from ultraviolet rays.

Even Steve Austin couldn’t fend off crow’s feet. Today’s advances could make the bionic man envious of the boomers who were once captivated by him.