Denise Olson danced at her daughter’s wedding.
That might not sound like a profound accomplishment, but it was a moment she could only dream of a few months earlier. Arthritis had worn away so much of the cartilage in Olson’s right knee that it was just bone grinding on bone. The pain had steadily worsened for two years, making it difficult for her to walk up the stairs of her home. She teaches first grade in Irvine, Calif., and it’s tough to meet the all-day needs of 30 kids when you can barely rise from your chair.
On April 23, she had total knee replacement surgery. Four weeks later, she was back in class. On July 13, her daughter Lauren got married, and Denise was able to walk down the aisle and dance at the reception.
Better implants, improved surgical techniques and a more in-depth understanding of how to treat a patient’s pain during and after surgery have helped make total knee replacements available to a wider patient base, from younger people such as Olson to long-suffering seniors.
The evolution of the procedure comes at a time of surging demand: About 600,000 total knee replacements were performed in the United States last year, and that number is expected to increase to 3.5 million a year by 2030.
“The need for surgery is exploding,” says James Caillouette, surgeon in chief at Hoag Orthopedic Institute in Irvine.
Shorter hospital stays and faster, less painful recovery periods have made the operation popular among patients who are both older and younger than used to be the norm for such candidates. Baby boomers are hitting the age at which their knees are wearing out, and they’re not willing to give up their active lifestyles without a fight.
“I would say at least half of my patient population is under 65,” Caillouette said. “Twenty years ago, that was not the case. But it’s not unusual for me to see a patient in their late 30s or 40s with end-stage arthritis who needs surgery. We used to be very fearful of doing that, because we didn’t think the implants would last very long. Now, with the new generation of designs and materials, they look like they’re going to last a very long time, 20 to 30 years or longer.”
But even the boomers’ Greatest Generation parents are getting the implants in higher numbers. Life expectancy keeps increasing, of course, but there’s also a greater awareness of how quickly health can decline if immobility leaves an elderly person homebound and isolated.
How it works
Total knee replacement, also called arthroplasty, might be a misnomer: The entire knee isn’t cut out. In fact, many of the parts are kept in, including the ligaments at the edges of the joint, the lateral and medial collateral ligaments, as well as the patella bone and its own ligament.
The procedure is commonly recommended in people whose articular cartilage, which covers the thigh bone (femur), has been ravaged by degenerative osteoarthritis. The meniscuses, the disc-shaped pads between the cartilage on the femur and the shinbone (tibia), can also wear over the years.
The femur and tibia are shaved down to make way for the implant, which resurfaces the bones. “Imagine you’re essentially doing a retread on a tire,” Caillouette said. Most implants have a metal “tray” that holds a plastic platform that stands in for the meniscus. The covering on the femur is super-strong metal, and when the knee bends, the pieces glide on top of one another.
Earlier generations of the implant used titanium, but that metal was found to wear out too quickly, Caillouette said. Newer models use cobalt-chrome, a longer-lasting alloy. The plastics in them also are harder and more wear-resistant, says Caillouette’s colleague Robert Gorab, chief medical officer at Hoag Orthopedic Institute.
Several companies have come out with revised knee systems this year. At an annual meeting of orthopedic surgeons in Chicago earlier this year, there was so much buzz about the new versions of knee implants on display that the trade magazine Orthopedic Design & Technology dubbed 2013 “the year of the knee.”
New rollouts include the Persona by Zimmer, the Journey II by Smith & Nephew and the Attune by DePuy Synthes, a Johnson & Johnson subsidiary.
The latter was developed with help from Caillouette and Gorab, who were part of an international team of surgeons that worked on the Attune for more than six years. The project cost about $200 million, one of J&J’s most expensive ever.
Researchers studied how patients move, and what deficiencies had hampered previous designs. Although knee replacement had historically been a very successful procedure, some patients had complained that their implants felt unstable as they tried to walk stairs, or that the gadgets simply felt strange inside them.
“The goal was, what’s it going to take to make it invisible?” Caillouette said.
The science of pain
Hoag Orthopedic Institute, which opened in November 2010, has become one of the highest-volume orthopedic centers in the country. Nearly 1,500 knee replacements were performed there in 2012, a 28 percent increase over 2011. DePuy launched the Attune in March (Caillouette implanted the first one on the West Coast), and between that model and the others, the 70-bed hospital should become an even busier place.
Patients are usually kept for at least one night after undergoing the procedure, but the protocol for their treatment has changed vastly over the years.
Knee surgery hurts, a lot, and this used to be a deal-breaker for many patients. But Caillouette says patients receive different kinds of pain treatment: Gone are the days when only general anesthesia would be used, leaving the patient groggy and out of sorts upon awakening. Also, more care is taken to avoid cutting soft tissue inside the knee.
“Now a patient will wake up from surgery without pain,” said Caillouette, who along with Gorab is a founding partner of the Hoag institute. “They don’t need IV narcotic pain medicine around the clock, because we’re giving them little doses of different things, as opposed to hitting them with a sledgehammer.”
Lieberman, of USC, says some patients can be given anti-inflammatories three days before the procedure, a step he calls “pre-emptive analgesia.”
A patient might receive a spinal anesthesia or a femoral nerve block, isolated in the knee area. Post-op, drugs can be administered that can last for days, giving the patient time to get up and moving. Patients are now encouraged, by nurses and physical therapists, to begin walking within six hours.
“They’re putting weight on it right away, that night,” Lieberman said. “That’s allowed us to discharge them earlier, which is very good for them mentally and medically. Patients can go home the next day, or two days after the surgery.”
Olson, who was one of Caillouette’s patients, was able to walk into his office for a checkup 10 days after her operation. She’s still in physical therapy to improve her lateral flexibility and range of motion.
Most implants adhere to the bone by a cement-like substance called polymethly methacrylate. The adhesive can eventually fail, as could other components; the plastic platform is also more likely to show wear than the metal above and below it (the platform itself can be replaced). Because of these factors, it’s unknown how long a shelf life the new generation of implants can have. That makes it tricky to recommend treatment to very young patients, such as those in their 40s. “Redos,” or re-implantations, can be complicated.
One goal is to create an implant that doesn’t need cement, and instead begins to grow into the bone. That would make it last longer.
Jerry Brooks of Newport Beach, Calif., got his arthritic right knee replaced in 2002, and his left knee in 2003. He says his X-rays show almost no wear at all in his models, called the Smith & Nephew Journey. He’d had problems with the right knee for years, and it finally gave out while he was competing in the 2001 Ironman Triathlon in Hawaii.
“I feel like I’m 25,” says Brooks, who is 72 and in remarkable physical shape, for any age. He doesn’t race so much anymore, but he still runs 25 miles a week, bikes 150 miles, and swims 5,000 to 8,000 yards. “I’m grateful for the fact that I got two gifts, so I can continue doing what I want to do.”
Lieberman says those kinds of stories inspire him. He received a letter from a woman who told him, “I think about you every day” and “You changed my life.”
“How many people tell you that in your life, ever?” Lieberman said. “You get these cards from people, and they’re traveling all over the world. They’re on their bicycles and they’re on cruise ships.
“It’s not life and death, but quality of life has become so important that people really appreciate it. Particularly if they’ve been debilitated for a long period of time.”