Know Before You Go: Knee Replacement

Know Before You Go: Knee Replacement

Have you had to cut back on activities because of knee pain? Knee replacement surgery is less invasive, with a faster recovery time than ever.

Have you had to cut back on activities of daily living because of knee pain? Have you found it more difficult to negotiate stairs, get out of your car or stand from a sitting position? Do you limit the number of steps you take because it causes knee pain? Have you been a fall risk and need ambulatory device? If you have answered yes to any of the questions you may be a candidate for knee replacement.

Total knee replacements jumped 86 percent for men and 99 percent for women between 2000 and 2010, according to a 2015 report from the Centers for Disease Control and Prevention. “Total knee replacements are one of the most common procedures performed by orthopedic surgeons in the US,” says Thomas Carrell, MD, an orthopedic surgeon and medical director of the Medical City North Hills Joint Program in North Richland Hills, Texas.

Partial knee replacements are getting more common as well, according to Dr. Carrell. The knee has three compartments—the inner side of the knee (medial), the outer side (lateral) and under the kneecap (patellofemoral)—and a partial knee replacement would be surgery on one.

Before the procedure
You and your healthcare provider will ensure that a knee replacement is the right procedure for you. Carrell says the ideal knee replacement candidate is one who has a chronic condition like osteoarthritis, psoriatic arthritis, osteonecrosis or a congenital deformity, and more conservative measures like physical therapy haven’t relieved the pain.

Expect to do some preoperative physical therapy designed to get you ready for the procedure and the recovery. “It’s kind of like doing homework,” says Carrell. “Patients don’t enjoy it but it will help them recover more quickly.” 

In the past, says Carrell, the average patient was in his or her 60s. “Now it’s 40s or 50s,” he says. “Baby boomers are the patients who come to me for replacements, and for lifestyle reasons they feel it’s very useful.”

Conditions that may disqualify you from knee replacement surgery:

  • Angina
  • Deep vein thrombosis or other blood problems
  • An ongoing infection
  • Immunosuppression, such as chronic kidney disease
  • Extreme obesity
  • Unhealthy skin around the joint
  • Lung problems
  • Weak quadriceps

Carrell is also cautious about operating on chronic pain patients who regularly use opioids. Pain medication may allow you to be more active than you probably should. If you take some medicine and go for a run on an already-damaged knee, you might be doing even more damage to it.

What to expect from a knee replacement
The surgery itself has come a long way since the first knee replacement was performed in 1968. “Surgeons have been refining their ability to be minimally invasive,” says Carrell. “Where once there was a lengthy incision, now it’s a short incision.” According to Carrell, in the past surgeons basically had to destroy the knee to operate. Tools such as saw blades and cutting jigs have become smaller as well, he says.

Knee replacements don’t last forever, says Carrell, but they last much longer than they used to. “Now the revision products are as good as the initial knee replacement,” he says. “What that means to patients is if you have a revision, you may be able to count on 20 or 30 more years. In the past the revision products wore down quicker than the original.”

An initial knee replacement is actually less complicated than a revision, according to Carrell. “The first time is more elementary saw cuts,” he says. “The way we put revisions together is very different from the first replacement, usually more demanding on the surgeon and longer and harder for the patient.” Damage to the bone around the implant requires the surgeon to adjust the cuts and fit a new piece like a puzzle into the existing anatomy and replacement structure.

Recovering from the procedure
Recovery from a total knee replacement takes about six weeks, says Carrell. “The first two weeks is dedicated to convalescence at home and exercise,” he says. “In the second two weeks, you shed your medical devices (like walkers or crutches) and transition to a cane. The last two weeks you’re off your devices and continue to exercise the knee.”

Don’t think you can return to your pre-operation levels of activity right away, though. “A total knee replacement is not an automatic jump up and go,” Carrell says. “ It does take several months to do certain endeavors.” You can probably do some walking or other light exercise by six weeks, but high impact exercise may be off the table for months—or forever.

Pain after surgery
Pain is still a factor for up to three months after the surgery, though it’s not as bad as it used to be, according to Carrell. The surgeon will probably give you a non-opioid painkiller for the first 72 hours. “That helps the patient get up and moving right away because they’re not in as much pain,” he says.

Pain management will be important beyond the first few days as well. “Good pain control monitors the amount of scar tissue and stiffness,” says Carrell, by allowing you to be active and engaged during your physical therapy and recovery. “If patients manage pain properly with the advice of their healthcare provider, they’ll have less scar tissue formation.” The more scar tissue you have, the stiffer your knee will be and the less range of motion you’ll eventually have.

The biggest mistake you can make, says Carrell, is not being serious about your physical therapy. “If patients don’t participate in proper PT where they’re working hard to regain motion, they can get stiff,” he says. “It can be unsafe to return to certain endeavors and they can incur fractures because they’re not quite strong enough.”

Medically reviewed in October 2018.

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