UAB orthopedic surgeon K. David Moore, MD, believes the partial knee replacement system UAB is using for osteoarthritis patients will provide the longevity that has been missing from previous components.
"It's a unique design," he says, "and at the moment it's the only model available in the states with this particular construction."
The system is used for patients whose osteoarthritis is limited to one compartment of the knee. It consists of a meniscal-bearing unicompartmental knee with three parts: a femoral, tibial, and tibial meniscal-bearing component. "This system has a cobalt chrome component on the end that replaces the damaged cartilage on the end of the femur," Moore says, "and another cobalt chrome tray that replaces damaged bone on the tibial side. There's also a mobile polyethylene component that moves like a person's meniscus moves. We believe this design provides better longevity than what we've seen in some of the other unicompartmental systems."
In the past, partial knee replacement surgeries have provided patients with good pain relief, Moore says, but the longevity of the units tended not to be as good as conventional knee replacement therapy. "That's part of the reason this type of operation fell out of favor," he explains. "There was never a question that it gave good pain relief, and that patients experienced good motion and recovered quickly — it just didn't seem to last as long."
Based on literature from Europe, where the unicompartmental knee system has been in wide use for several years, Moore believes it has the potential to last as long as a total knee replacement: "The FDA released this system for use in the states about two years ago, and we started very using them very quickly thereafter."
In most patients who develop arthritis of the knee, the disease begins at the inside portion, or "medial aspect" of the knee. "If you catch the disease at that early stage, where that's essentially the only area that's been damaged, then it's reasonable to replace only that damaged area with this smaller implant," he says. "But if there's damage or arthritis in the rest of the knee, then this is not an appropriate remedy. In that type of situation, it's best to do a total knee replacement."
Moore says that referring physicians should be aware that their patients have the opportunity at UAB to utilize an implant that has only been recently released in the United States, but which has a long and excellent track record in Europe. He says the device gives orthopedic surgeons the potential of being very directed in approaching knee arthritis. "From a surgical standpoint," he says, "we're able to make smaller incisions, with quicker recovery time and generally less pain involved for patients, as opposed to total knee replacements. And generally there's a better range of motion than patients would expect from a total knee replacement."
This type of operation is for patients who have tried other appropriate measures, Moore says. He doesn't think it's appropriate if patients haven't tried other conservative measures first. On the other hand, from a successful treatment point of view, patients wouldn't want to wait too long before having the surgery because at some point the arthritis will progress to involve the rest of the knee.
"It's appropriate to use some sort of antiinflamatory drug therapy and perhaps some activity modification," Moore says, "and perhaps some physical therapy. I don't want to give the impression that patients should be coming in for any sort of knee replacement. However, if we wait too long, it's possible to lose the window of opportunity for unicompartmental arthroplasty. So evaluation by attending physicians is key to the success of this procedure."
Moore says that research makes the difference at UAB orthopedics in general, and the division's joint replacement team in particular. "We have three physicians who not only subspecialize exclusively in the area of total joint arthroplasty, but who also participate actively in the innovation and evaluation of joint replacement implants and procedures," he says. "Patients should come to us with the confidence that our recommendations are based upon our exceptional clinical experience and a rigorous review of the current 'state-of-the-art' technologies, rather than the latest ad campaign by an implant manufacturer.
"Our expertise ranges from minimally invasive surgery and computer-assisted joint replacement to the most complex reconstructive challenges. The relocation to UAB Highlands (formerly the HealthSouth Medical Center on Birmingham's Southside) will allow us to continue world-class care in an environment that is both patient-focused and patient-friendly."
