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More than half of all older adults in the United States have arthritis. Most often it’s osteoarthritis (OA), where the cartilage between joints wears down, causing swelling, pain and disability in some.

Since the 1960s, people with severe OA have had the option of surgery to replace certain painful joints with prosthetics made of metal, ceramic and plastic. Knee and hip replacements are now the third- and fourth-most-common surgeries, respectively, in U.S. hospitals, behind Caesarean sections and circumcisions.

But while often highly successful, a joint replacement may not eliminate all pain or restore full range of motion in a hip or knee. “We can’t take someone who is doing awful and suddenly make them perfect,” says David Jevsevar, chair of orthopedics at the Geisel School of Medicine at Dartmouth.

Overall, hip replacement results are better than those for knee replacement. Only about 1 in 10 people who have hip replacement report persistent pain or dissatisfaction after surgery; with knee replacement recipients, it’s 1 in 5. Both surgeries carry risks, and not everyone is a candidate.

Here, what you need to know about the benefits and potential downsides of joint replacement:

When to consider surgery

If you have hip or knee OA, turn first to conservative measures. Depending on your level of pain or difficulty functioning, these may include exercise, physical therapy, weight loss, the use of over-the-counter nonsteroidal anti-inflammatories (NSAIDs) such as ibuprofen (Motrin IB and generic) and naproxen (Aleve and generic), and assistive devices such as canes.

For joint replacement, it’s ideal to hold off until you’re at an age when a prosthetic device is likely to last the rest of your life. (They usually last 10 to 15 years.) Yet, you don’t want to put it off so long that you’re too debilitated to gain back substantial function after surgery.

“We don’t have a way of predicting the sweet spot,” says Mary O’Connor, director of the Center for Musculoskeletal Care at Yale School of Medicine and Yale New Haven Hospital. But when pain or limited mobility begin to inhibit your daily routine, it’s time to talk with your doctor.

Set yourself up for success

If you and your doctor think joint replacement is reasonable, give yourself time beforehand to deal with health issues that may interfere­­, such as obesity or uncontrolled diabetes. And take these steps:

Pick an experienced surgeon. Choose one who frequently performs joint replacement and has a low complication rate: At least 50 surgeries a year and a 3 percent or lower complication rate are good benchmarks. The medical facility you choose should do at least 400 joint replacements annually.

Because a key risk of surgery is infection, ask about the facility’s overall infection rate (it should be less than 1 percent). Or check Consumer Reports’ hospital ratings.

Find out about recalls. Ask your surgeon whether the device he or she is planning to use has ever been recalled. And request the unique device identifier for your implant in case it is recalled in the future.

In addition, make sure that you don’t have an allergy or a sensitivity to any of the materials in your device and that your surgeon isn’t planning to use a metal-on-metal implant.

When it comes to techniques, don’t be dazzled by robotic or minimally invasive surgeries, which use shorter incisions, says Matthew Kraay, a professor of orthopedic surgery at Case Western Reserve University School of Medicine. They haven’t been shown to be more effective than standard methods, and surgeons may be less familiar with them.

Ask your doctors how they’ll manage your pain after the procedure. A multimodal pain management program is best, Kraay says. That means a combination of techniques, such as nerve blocks, epidural injections and NSAIDs. This approach can reduce the need for opioid medications.

If your doctor recommends outpatient joint replacement, be sure it’s right for you. The best candidates, Kraay says, are people in top health who are highly motivated to take on their rehab at home.

The best healing strategies

Most people used to need weeks in a hospital after a total joint replacement, Kraay says. Now those who have hospital-based surgery are increasingly likely to be discharged after a few days­ — and to go straight home instead of to a rehab facility. That’s better, experts say, because at home your risk of infection is lower and you’re usually more comfortable.

Because the hip is a much simpler joint than the knee, and the surgery much more straightforward, it’s generally easier to recover from hip replacement and may not even require formal physical therapy, says Daniel Riddle, a professor of physical therapy at Virginia Commonwealth University. Normal activities such as bathing, cooking and climbing stairs often provide enough hip movement to keep your recovery on track. Most people will be about 90 percent recovered within six to eight weeks after surgery, with more small improvements over the next year.

With knee surgery, you can expect to do physical therapy two or three times a week for about a month and exercises at home daily. Riddle says the average person will need eight weeks to recover by about 80 percent. Full recovery may take up to 18 months.

In either case, to help your hip or knee implant last as long as possible, you should walk or exercise every day because it will help you heal and stay mobile long-term, but avoid high-impact activities such as running, jogging and heavy lifting. Instead, opt for biking, swimming or using an elliptical machine.

 Copyright 2018, Consumer Reports Inc.

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