Partial knee replacement gets orthopedic surgeon back in swing
Increasingly, though, the 61-year-old orthopedic surgeon was finding the wear in his right knee hindering his athletic drive. Over the years he had several scopes and endured several surgeries, including trying a cadaver's miniscus to fix the joint. Nothing worked well enough to get him back to winning form. "It was bone on bone, I knew I needed something," he says.
Last year he learned about ConforMIS, a 6-year-old Boston-based company that makes custom-made partial knee-replacement joints. In keeping with its procedures, Snyder sent the CT scans of his knee to the company, whose engineers then took two months to manufacture the made-to-measure part using its iFit technology. Once ready, in January, Snyder traveled to Boston for the operation with Wolfgang Fitz, a surgeon who helped to develop the procedure. He also spent time observing Fitz and learned how to conduct the surgery himself. Six weeks later Snyder was back on the handball court at the Newport News YMCA. Over Memorial Day weekend, he and his doubles partner Vern Roberts, a former pro player, took second place in the Marine Corps Semper Fi Handball Tournament in San Diego.
"I can move better than I've been able to in four years," says Snyder. "They're still my ligaments. It feels like my own knee." For athletes, it makes a big difference. "When I watch people with full-knee replacements, they freeze. They lose the split-second reaction because there's no natural connection between the top and the bottom.... With the partial, it seems like it's a lot easier to move. It feels more natural. You retain your agility."
The major difference from traditional surgery is that the ConforMIS replacement part is custom-made and patient-specific, which allows for much less cutting of the patient's bone. (In a traditional full- knee replacement, a surgeon chooses from about half-a-dozen available models and then has to work to fit it to the individual.) "It's bone-sparing. It's almost like a crown on your tooth," says Snyder, of the part which is made from traditional materials, plastic and metal alloy. It's anticipated that the exact fit of ConforMIS parts, the only "personalized resurfacing implants" for knees made anywhere, will also help them to last longer.
The less-invasive procedure in turn means a shorter hospital stay, shaving two days off the typical three days; this makes it popular with hospitals receiving Medicare payments as they keep any additional funds accrued from the two-day savings. For the patient it also typically involves a quicker recovery time and less danger of infection or complications. Snyder is working towards cutting out the overnight stay and making it an outpatient procedure "for the right type of patient," that is someone who is in otherwise good health.
"It's a fairly easy technique to learn. It's not experimental or revolutionary. It's like what we do all the time. It was just learning the sequence," says Snyder, who graduated from West Point in 1971 and spent 24 years on active duty before moving to private practice. "It comes with a pre-made cutting block and different bevels. There are outlines where you need to remove cartilage and where you need to put drill holes." This is another advantage for hospitals, which do do not have to stock anything for ConforMIS as the company ships everything that's needed for the procedure, apart from standard instruments, in one self-contained package; that replaces the usual need for five trays of implements, which then have to be inventoried, cleaned and sterilized - another cost-savings.
Ideal candidates for the operation, Snyder says, are those in their 40s and 50s, who've had prior knee scopes and have no cartilage left, but are not ready for a full knee replacement. "At 45 you don't want a full replacement, because you'll need another at 60," he says. And those, known as "revision" replacements, done when a full knee replacement wears out or fails are "salvage operations" at best, Snyder cautions. "You're told to lead a quiet life and not overdo it." He also recommends it for older patients with osteoarthritis, including those in their 80s.
He adds that most patients who have arthritis in the knee, which is a far more complex joint than the ball-and-socket hip - "everyone's looks the same" - don't have it in all parts.
With ConforMIS' partial replacement, patients can replace either the kneecap, inside, or outside - "there's never been a good system for the outside," Snyder observes - and still have the option of a first full knee replacement down the road, if necessary. "It leaves choices going forward," he says, crediting advanced imaging techniques with making the procedure possible.
Snyder's now performing about three partial knee-replacement surgeries on his operating days - each takes about 90 minutes - at several of the area's hospitals. And he's playing handball three times a week.
NEWS TO USE
Dr. Robert "Bob" Snyder practices with the independent orthopaedic group, Orthopaedic & Spine Center, 250 Nat Turner Drive, Port Warwick, Newport News, 23606.
For information, call 596-1600; or go to www.osc-ortho.com
For more information about ConforMIS, go to www.conformis.com