There are about 790,000 total knee replacements and 544,000 hip replacements done every year in the U.S.—and those numbers are expected to grow as the population ages, according to the American College of Rheumatology.
Intended to help relieve pain and improve function, knee and hip replacements are considered two of the most successful medical interventions of all time, says Dr. James Huddleston, an orthopedic surgeon at Stanford Medicine. He is also the president of the American Association of Hip and Knee Surgeons and the chair of the American Joint Replacement Registry Steering Committee.
The average age to receive a knee or hip replacement is 65, according to the American Academy of Orthopaedic Surgeons, making knee and hip replacement surgeries common among Medicare beneficiaries.
Causes of knee and hip pain and dysfunction
In older adults, knee and hip pain is typically caused by osteoarthritis, says Huddleston.
“Osteoarthritis is caused by lost cartilage on the ends of the bones,” Huddleston says. “Cartilage is the soft substance that acts as a shock absorber on the ends of the bones. It's akin to a tire on a wheel.”
Some knee or hip problems can start at birth, such as hip dysplasia, where the hip joint is shallow. But just like a tire needs to be driven a certain number of miles before it becomes a problem, it can take many years for the cartilage to break down, says Huddleston. Injuries and obesity can also put pressure on knees and hips, eventually leading to arthritis, he says.
Non-surgical treatments for knee and hip pain
As with many types of aches and pains, the first course of treatment for knee and hip pain and dysfunction is non-steroidal anti-inflammatories (NSAIDs) says Dr. Huddleston.
The next level of treatment is physical therapy, he says.
The third level of treatment for knee pain and dysfunction can be unloader knee braces, which work by realigning the knee to shift weight to an area where there is more cartilage, to reduce pain and improve function. Unlike braces you can buy in a doctor’s office or online, these braces must be prescribed by a doctor and fitted by a prosthetist, says Huddleston.
If knee and hip pain are still challenging, patients may opt for steroid injections of cortisone, which are injected into the affected area to reduce the inflammation and pain.
Patients can also get injections of hyaluronic acid to help lubricate the joints, says Huddleston.
Injections may work quickly, with pain lessening in a day or less, but are only temporary fixes. Additional injections may be needed for pain management, and at some point the body may develop a tolerance for them and they won’t work as well or at all, says Huddleston.
The newest types of injections are biologics, including stem cells and platelet-rich plasma. Some studies show that they help with pain, but they don’t regrow cartilage yet, says Huddleston.
What happens in a knee or hip replacement surgery?
The final level of treatment for knee and hip pain is surgical.
In partial or full knee and hip replacements, bone and cartilage that have deteriorated are replaced with metal and plastic parts.
Knee and hip replacement surgeries take about 90 minutes, says Huddleston, and you might stay overnight in a hospital, or leave the same day.
“Within three months, patients are about 90% recovered,” says Huddleston.
Does Medicare cover knee and hip replacements?
Medicare has coverage for most of these knee and hip dysfunction treatments, including joint replacements.
It doesn’t cover the biologic injections, but it covers everything else, says Huddleston.
“Medicare covers partial and full knee and hip replacement surgery if the procedures are considered medically necessary,” says Emily Whicheloe, director of education at the Medicare Rights Center.
Medically necessary, as defined by the Centers for Medicare & Medicaid Services (CMS), means a patient meets the following criteria:
- Imaging, such as an MRI, shows joint deterioration
- They have used non-surgical treatments, such as medication, physical therapy, and injections without significant success
- They have difficulty doing activities of daily living
How much does a hip or knee replacement cost?
The average patient's out-of-pocket cost for a knee replacement or hip replacement is about $2,000.
“If a patient has the procedure in a hospital and stays in the hospital as an inpatient, Medicare Part A covers it, and the patient may owe a deductible of $1,632,” says Whicheloe. “Outpatient procedures performed at a hospital or ambulatory surgical center are covered by Medicare Part B.”
Everything covered by Medicare Part B is subject to co-pays (with applicable caps) and any unmet deductible for the year.
“Medicare Advantage covers the same treatments as Medicare, but may have different co-pays and deductibles depending on the plan,” says Whicheloe. “Make sure that you choose a surgeon and facility in the Medicare Advantage plan network, to get coverage,” she says.
Patients on Medicare should use facilities and surgeons approved by Medicare to receive coverage, she says.
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