‘GPS’ improves knee and hip replacement outcomes

When you get new tires on your car, it’s important that they are balanced and in alignment. This will keep the car from vibrating or pulling in one direction and help the tires last longer.  

But you wouldn’t expect your mechanic to check tire alignment and balance just by eyeballing it. They have specialized tools to help them. It’s the same when the joints in your knees or hips are replaced.  

For many years, surgeons largely relied on bony landmarks and their intuition to make sure joint implants were placed in the correct position and properly aligned, leading to a straight leg. But not every person’s body is the same, so even an experienced surgeon could miss the mark by just a little. Being even slightly out of position can lead to an implant wearing down unevenly, requiring a new one years before expected.  

With people living longer and more people having joint replacement surgery at a younger age, it’s more important than ever to do what we can to extend the life of these implants and reduce the number of future procedures a person may need.  

Related reading: Am I too young for knee or hip replacement?

Thankfully, many surgical teams, including ours, now have surgical navigation systems that help position and align new joints with a degree of accuracy we can’t get by eyeballing it.  

‘GPS’ for knee and hip replacement

In traditional joint replacement surgeries such as knee replacement, we would use simple tools such as alignment jigs and rods inserted along the thigh bone (femur) to help us see and feel when the knee was properly positioned and aligned.  

A surgical navigation system is similar to a GPS system in a car. We input where in the limb we want to go, and the system shows us, in real time, the location and movement of our instruments. We can clearly see and test position, alignment and ligament tension every step of the way. 

Surgical navigation systems are similar to GPS in a car. Showing location and movement of our surgical tools in real time. via @MedStarWHC

There are two types of navigation systems:  

  • Computer-assisted navigation systems provide information about our surgical tools and the implant in relation to the target position.  
  • Robot-assisted navigation takes this one step further, using robotic arms to align cutting guides and increase the precision of bone cuts. This doesn’t mean the robot does the procedure; it just refines our surgical execution. The surgeon still controls every step. This technology is still emerging and fairly expensive, so it’s not as common as computer-assisted navigation.

Benefits of using navigation during joint replacement surgery

Every person’s body is a little different, which can make getting an implant into the correct position tricky. We can’t always rely on bony landmarks and a patient’s anatomy. For example, if you have hip arthritis in addition to a spine disease, you may hold your pelvis in an odd way. Without a navigation system, we may place the implant slightly off of where it should go because of how you’ve held yourself for years.  

Navigation systems give us an extra set of eyes, along with a certain amount of confidence and predictability. Some benefits include:

  • Providing the surgeon with real-time information and the ability to correct potential errors during surgery
  • Improving overall function of the new joint, including greater stability and range of motion
  • Potentially allowing the use of less-invasive surgical techniques because the system gives us improved visualization of the field without large incisions
  • Increasing the life of the implant and reducing the need to replace the implant, known as revision surgery  

Revision surgery often is more complex than the original knee replacement or hip replacement surgery. The surgeon may need to remove some of the bone because the implant may have grown into it. This would require a bone graft, or transplanting a piece of bone from either another part of the body or from a donor to replace the removed bone along with the implant.  

A 2015 study showed that 5.2 percent of patients who had a total knee replacement without computer navigation needed revision surgery within nine years, compared with 4.6 percent who had computer-navigated surgery. This may look like a small variance, but if you have 1 million knee replacements, it could mean the difference of 6,000 of them avoiding revision surgery within nine years.  

Joint replacement surgery can dramatically improve a person’s quality of life, and demand for these procedures is growing. The American Academy of Orthopaedic Surgeons says nearly 1 million knee and hip replacements are performed every year in the United States. The organization predicts that number will rise to 4 million, due to an aging population and increase in obesity and osteoarthritis.  

As these procedures become even more common, computer- and robot-assisted navigation will continue to play a larger role in helping us improve patients’ outcomes and increase the longevity of their implants.

Am I too young for knee or hip replacement?

A 30-year-old man came to our emergency room with excruciating pain in both hips. He had been experiencing pain for several years, but it had become so bad he hadn’t been able to walk for a couple weeks. Imaging showed advanced bilateral hip arthritis—bone was rubbing on bone.

After a total hip replacement and physical therapy, he’s back to work and tells me he has more mobility than he’s had in years. Thirty may seem young for a joint replacement, but a growing number of younger people are getting these procedures.

Our team performs more than 400 joint replacements each year, and the average age of our patients is 60. But according to the American Academy of Orthopaedic Surgeons, the number of:

  • Total knee replacements increased by 120 percent from 2000 to 2009, and 188 percent for patients age 45 to 64.
  • Total hip replacements increased by 73 percent in that timeframe, and 123 percent for patients age 45 to 64.

It’s a common misconception that knee replacements and hip replacements are just for the elderly. I’ve heard patients say, “Grandma didn’t get a knee replacement until she was 80. I figured I’d just have to deal with the pain until then.”

If you’re unable to live the life you want due to pain, consider joint replacement surgery sooner than later.

Listen: Dr. Thakkar discusses more myths about joint replacement surgery on the Medical Intel podcast.

Why are younger people getting joint replacements?

A couple decades ago, most hip and knee replacement patients were older than 70. That was largely due to the fact that our implants weren’t nearly as good as they are now. They only lasted about 10 years, so doing surgery wasn’t always worth it if you knew you were going to have to redo it two to three times during someone’s life.

Our implants now are much better and last much longer. In fact, a 50-year-old who gets a knee replacement has a 70 percent chance of it lasting until they are 80. That’s 30 years of being able to work, run, bike or play golf pain-free. And current hip replacements are lasting up to 25-30 years.

Osteoarthritis, which is a common reason for hip and knee replacements, is connected to wear and tear on the joints. It’s only natural that your risk of getting it increases as you age. But we’re also seeing it in more patients who are middle age or younger. This could be due to two factors:

  • Popularity of high-intensity sports: Repetitive actions and injuries, such as tears to the cartilage that cushions the joint, increase the risk of arthritis. More people are taking part in activities, such as running and biking. For example, according to Running USA, 17 million people finished a race in 2015, compared with less than 5 million in 1990. While healthy, these activities also can be hard on the joints.
  • Obesity: Carrying extra weight puts increased stress on the joints. Being 10 pounds overweight can put an extra 40 pounds of pressure on your knees. One study found that obesity was strongly associated with the need for knee or hip replacements, with 72 percent of the study group (age 18-59) classified as obese compared to 26 percent of the general population.

"Being overweight puts increased stress on the joints. An extra 10 pounds adds 40 pounds of pressure to the knees." via @MedStarWHC

When should I consider a knee or hip replacement?

Don’t think about your age when considering joint replacement surgery. Instead, consider your pain and mobility. Do you struggle to walk a short distance or drive a car? Are you unable to perform work duties? Do you consistently take medication to control the pain?

Conditions, such as arthritis, also can affect your general health. You may find yourself giving up activities one by one as they become too painful. Eventually, lack of exercise may cause weight gain and conditions that can accompany it, such as diabetes and high blood pressure.

You may benefit from a knee or hip replacement when:

  • Pain and stiffness limits everyday activities or interrupts rest or sleep
  • It becomes necessary to use a cane or walker to remain mobile
  • Treatments, such as anti-inflammatory medication, cortisone injections, physical therapy or less-invasive procedures fail to relieve pain
  • An abnormality develops, such as bowing in or out of the knee

Our bodies sometimes break down, affecting quality of life. Fortunately, in some cases we can replace the faulty parts and return mobility. While those new parts may wear down eventually, advancements in technology help us give younger people more years to do what they love—pain-free.

Request an appointment to see if joint replacement surgery is right for you.

Breaking Down the Myths of Joint Replacement Surgery

Tune in to the full podcast interview with Dr. Thakkar.

If knee or hip pain is starting to limit your life, it’s time to think about repairing or replacing those aching joints, rather than retiring from the game. And the sooner you seek help, the better, experts agree.

In fact, one of the worst things you can do with deteriorating joints is postpone surgery until the pain is so bad that you can no longer walk, golf or engage in other activities. That’s because waiting until your condition worsens can make you sedentary, introducing a whole host of other problems.

“Restricting activity often leads to weight gain which can aggravate an already compromised knee or hip joint,” says orthopedic surgeon Savyasachi Thakkar, MD, of MedStar Orthopaedic Institute at MedStar Washington Hospital Center. “Plus lack of use can weaken your muscles and slow your recovery from surgery.”

Along those same lines, Dr. Thakkar also cautions against waiting until you’re older to consider joint replacement.

“Surgery can improve your quality of life for years to come. So, even if you’re under 50, don’t think you’re too young for the procedure.”

Technological advances over the years have resulted in shorter hospital stays, less pain and faster recovery. Additionally, new, improved materials are far more durable, reducing the chances of a repeat replacement in the future. Studies show that between 60 to 70 percent of patients today can expect their joint replacement to last 25 to 30 years.

The fear of being bed-ridden after surgery, with little or no return to normal range of motion, is another persistent myth.

“I schedule hip replacement surgeries, which typically take about two hours, in the morning, and we may have you up and walking by noon,” Dr. Thakkar says. “You could be walking soon after knee surgery, too.”

Some activities may be restricted during the first six to eight weeks of recovery, based on the procedure performed. But soon thereafter, patients can expect to resume their usual activities with a full range of motion.

“Joint replacement surgery has advanced tremendously over the last few years,” Dr. Thakkar concludes. “The minute joint pain affects you—your work, quality of life, or ability to live independently—you should see a specialist for an initial evaluation. We can help you live your life fully, in balance and pain-free.”

Tune in to the full podcast interview with Dr. Thakkar.

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