Imagine hanging cabinets using educated guesswork.
The potential result: a wobbly kitchen.
And yet, just a few years ago, before the arrival of robotic-assisted surgery, three-dimensional imaging and custom-fit implants, this was the challenge surgeons faced when performing knee and hip replacements. Perfect alignment of implants could be hit and miss. Patients endured longer recovery times because muscles were cut. Rehabilitation was beset by limitations and requirements, which made knee and hip replacement a less-than-thrilling prospect for the hundreds of thousands of people who suffer from arthritis or joint injuries.
“Despite the fact we did do a good job with hip replacement, to pat yourself on the back for a procedure that hadn’t changed in 30 to 40 years isn’t perfect,” said Dr. David Padden, orthopedic surgeon at Holy Cross Hospital in Fort Lauderdale.
But now, thanks to advancements in technology, accuracy is greatly improved.
Holy Cross was an early adopter of MAKOplasty, a robotic arm-assisted device for partial knee procedures in 2006.
Since October 2011, the hospital also has used the process for hip replacements. The surgeon-controlled robotic arm system enables the accurate alignment and positioning of implants.
The system delivers a three-dimensional image of the patient’s hip from a CT scan. The surgeon uses this model to position the hip implant components — a cup and liner placed into the socket of the pelvis and a femoral component with head and stem.
A Massachusetts General Hospital study of 1,823 hip replacement patients in 2011 found that surgeons were off 50 percent of the time in the placement of these implants, some as far off as 10 degrees from optimal placement.
“If I had an instrument that could always point me to the right angle and directions and to do the carpentry to a degree of accuracy and precision we’d never seen before, I’d be foolish if I didn’t try this ... the use of the robot,” Padden said.
He explains the procedure:
“Our robot is essentially helping me by giving me actual information in real time while I’m doing the surgery. Instead of planning the surgery off a two-dimensional X-ray, I’m planning off a CAT scan representation of their hip in every direction. On the virtual computer I am able to place the actual socket and femur stem where I’d like them to be. We manipulate those things to size them better, all on the computer, before we start the surgery,” he said.
Dr. Richard Levitt, an orthopedic surgeon with Baptist Health, also uses the robot to assist in resurfacing the knee, an early-intervention procedure that can alleviate pain and improve the knee’s function by cleaning out bone spurs in the joint. The procedure can put off the need for a total knee replacement for a number of years. Levitt also uses the robot for partial knee replacement.
“The robot will only allow you to cut bone to a certain depth and certain positions by the pre-operative plan. It doesn’t allow you to cut beyond those parameters,” Levitt said. “If you can properly position that implant, it will give you a better result than one put in cockeyed or twisted. The major advantage of the robot is that it is as close to a perfect implantation as possible. We first started using it about four to five years ago for partial knee replacements and are now using it for total hip replacements. It will probably be available in the near future for total knees and, ultimately, for some work in the shoulder as well.”
The hallmarks of resurfacing and partial knee replacement, using the robot assist, means a smaller operation, smaller incision, faster recovery and minimal rehabilitation. “You can get back 100 percent of motion, which is important,” Levitt said. The implants can last at least 10 to 15 years.
“People say it feels more like a normal knee,” he added. “Virtually everybody, when I do a partial knee, stays in the hospital one night and is home the next day. Usually, they are walking on crutches or a walker and start physical therapy right away. As soon as they feel they can walk on it, they discard the crutches and walker. The average person, by the fifth or sixth day, most are walking with nothing.”
Jerry Amster, 67, a retired attorney who lives in Coconut Grove, had a hip implant in 1999 on his left side, and in October 2012 had an implant in his right hip. Both surgeries were performed at Doctors Hospital in Coral Gables. “Both came out great,” he said.
But that’s where the comparisons end.
“The technique I had back then, the posterior way, they cut muscles before they came up with smaller incisions. I had a big incision and the risk of infection is always a problem. I was fortunate and never had an infection and it worked out great but there were a lot of restrictions for a number of months — no crossing your legs, tying your shoes, a whole bunch of things I couldn’t do so as not to dislocate the hip. That was then.”
Amster started to feel pain in the right side a decade later and was losing cartilage on the right hip. He opted for surgery with orthopedic surgeon Dr. Alexander van der Ven. He went into the hospital on a Monday morning and was home by Wednesday morning.
“I was not in any pain. Getting out of the hospital means emotionally and mentally you feel 100 times better. I was out in 48 hours; 13 years ago, I was in the hospital almost five days. I said, ‘When I get home, what are my restrictions?’ He said, ‘Common sense, and don’t get in any positions you haven’t been in before.’
“I was literally full-weight bearing one week after the operation,” Amster said.
Surgery is not always the first option. Patients are often counseled on activity modifications, such as weight loss or strength and flexibility training, guided by a physical therapist to improve certain muscles that may be underused. Sometimes medications or injections are recommended.
“Those small interventions can make a huge impact,” van der Ven said.
When surgery is chosen, “the trend is less invasive techniques,” van der Ven said. “We make smaller incisions and can avoid muscle damage by going around muscles rather than cutting. We use different types of implants or prosthetics that really take away less bone and that will last, potentially, for the remainder of someone’s life.”
Dr. Marc Umlas, chief of orthopedic surgery at Mount Sinai Medical Center in Miami Beach, calls the current treatment “a paradigm shift in thinking in hip replacements. In the old days we cut first and ask questions later. Now we start with a small approach and visualize in a much smaller area and have developed a number of instruments for facilitating this. This enables us to replace a hip through quite a small incision with excellent results.”
Custom fit implants
The latest technology in total knee replacement surgery is now custom fit implants.
“It’s one step above the robot in the sense that rather than taking an off-the-shelf implant and using the robot to put it in, we’re getting focused, specific guides, matched to the anatomy. This really will be the next wave of where we go in medicine,” van der Ven said.
Or, as fellow Baptist Health orthopedic surgeon Dr. Francisco Borja said, “Rather than fit the patient to the prosthesis, why not fit the implant to the patient?”
Surgeons take a CT scan of a patient’s knee, hip and ankle and send it to ConforMIS, a Boston-based medical device company specializing in converting CT data into implants that are precisely sized and shaped to conform to an individual’s exact topography.
“They create a virtual knee, which is your knee,” Borja said. “The consequence is these patients recover faster, they don’t have to have as much therapy and don’t have as much pain and move faster and more naturally. They are not fighting with their own soft tissues because of a decision I made in surgery. This has been made for you. This is a significant step forward for mechanical devices.”
Patients with serious medical issues, such as a heart condition, hypertension and other ailments may not be candidates for the ConforMIS custom knee. The prosthesis, once created, can only be used for that particular patient. If they are not suitable for surgery, the device can’t be used for someone else, Borja said.
There are no custom-fit hip implants yet, but Borja expects customization there to come in the near future.
Partial knee replacement
Customized cutting tools tailored to the individual patient’s bone topography also make knee surgeries more accurate, Umlas said.
The knee is made up of three compartments — medial, the side of the knee closest to the body’s center; lateral, the side of the knee to the outside of the body; and the patellofemoral compartment, behind the knee cap. When only one portion of the knee is affected by arthritis, a partial knee replacement can be performed.
“What’s exciting about that is a partial can be done as an outpatient, or, at most, one night in the hospital, and so the recovery is much quicker than a total knee,” said Dr. John Uribe, medical director of Doctors Hospital Center for Orthopedics & Sports Medicine and chairman of the orthopedic department at Florida International University School of Medicine.
“With partial knee replacements, it’s a much less mechanical feeling … more natural,” Uribe said.
With boomers and seniors living longer and active longer, knee and hip replacement surgeries are common procedures in the United States, with about 719,000 knee replacements and 332,000 hip replacements in 2010, according to the Centers for Disease Control and Prevention. These numbers are projected to grow significantly over the next 15 to 20 years.
“New technology has always been an exciting part of our profession,” said Dr. Raymond P. Robinson, chief of Joint Reconstruction and professor of Clinical Orthopaedics at the University of Miami Miller School of Medicine. “Companies and physicians frequently introduce these new technologies with great excitement and fanfare. The hard part is determining which of these actually advance the results and outcomes for our patients.
“For example, contemporary total knee replacement performed with today’s modern techniques result in 97 percent good or excellent results and implants of best design are lasting more than 30 years in actual patients,” Robinson said. “When the excitement of the ever-present new technology subsides all too often the only ones left are the patient, their implant, and hopefully the surgeon who did the operation. Long-term clinical outcome measurements are key in determining which technologies actually improve the care of our patients.”
The good news?
“Less pain the day after surgery than the day before surgery. Life is motion. Most people have places to go, places to see,” Umlas said.
“I had a woman who was 96 who was told she was too old to have this [hip] surgery. Age is not a parameter, it’s about health,” Umlas said. “I saw her six months after surgery. She walked in feeling great and came in with a new boyfriend. She said she was denied a lot of fun in life because doctors had judged she can’t be helped. Within a day of her surgery she was feeling better than before her operation and in six months was walking independently. That’s what makes this rewarding, to restore function to people.”
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