For years, total knee replacement has been the gold standard for reconstruction of the knee in patients with end-stage arthritis, but physicians have been seeing more and more patients with arthritis in only one compartment of the knee, according to Scott Appell, MD, an orthopedic surgeon with Lemak Sports Medicine in Birmingham. The Oxford® Partial Knee System is the answer for many patients, and Appell was one of the first surgeons in Alabama to perform the procedure.
“We’ve been trying to answer this problem for years,” Appell says. “In the past, to try and avoid total knee replacement, we would do an osteotomy to change the direction of force in the knee joint or cut the tibia to restore alignment. But neither fixes the cartilage. These treatments would work for a while, but started to deteriorate after about five years.”
For those patients with single-compartment arthritis, the Oxford Partial Knee offers a favorable option to total knee replacement. The partial knee can be applied to all three components of the knee – medial, lateral, and patella-femoral. Most commonly used for the medial compartment replacement, partial knee replacement aims to preserve healthy bone and cartilage in the unaffected compartments and is much smaller than a total knee implant.
“The partial knee procedure allows for 75 percent less bone and cartilage removal and is less painful. It enables a more rapid recovery and provides more natural motion when compared to the total knee replacement,” Appell says.
The Oxford Knee is the evolution of the original meniscal arthroplasty, which was first used in 1976, according to Biomet. It continues to offer the advantage of a large area of contact throughout the entire range of movement, which assures minimal polyethylene wear. Since 1982, phases one and two of the Oxford Partial Knee were mainly used to treat anteromedial osteoarthritis. If performed early in this disease process, the surgery can arrest the progress of arthritis in the other compartments of the joint and provide long-term relief of symptoms.
The phase three implant is based on its clinically successful predecessors and provides several advantages, which include:
- five sizes of the femoral component for improved fit and reduced bone removal
- anatomically shaped tibial components for optimal tibial coverage
- redesigned meniscal bearings to minimize impingement
- a reproducible technique using a minimally invasive approach, which offers quicker recovery and lower morbidity.
Thirty years of clinical history and continual improvement in the Oxford partial knee have provided a 98-percent survival rate at 10 years. Current data, says Appell, shows 90 percent satisfaction after 10 years in the U.S. and 95 percent satisfaction after 15 years in the United Kingdom. “Basically, we are seeing the same satisfaction that we see with total knee replacements,” Appell says. “The key is to do a good job selecting patients for the procedure.”
Any patient with single-compartment arthritis is a candidate as long as both cruciate ligaments are intact. “The posterior cruciate is seldom diseased in osteoarthritic knees, but the anterior cruciate often is damaged and sometimes is absent,” Appell says. “Since the implant is completely unrestrained in the anteroposterior plane, the stability of the prosthesis depends on an intact cruciate mechanism. Stability cannot be restored if the anterior cruciate ligament is badly damaged or absent and this deficiency is a contraindication to the procedure.”
Appell says that young patients typically do better with the partial knee procedure, but anyone with well-functioning ligaments is a candidate. In fact, the Oxford information states that the surgery can be performed in patients in their 70s and 80s. “It’s not just for young people. We do the partial knee replacement with the idea that it is the one procedure the patient needs and that we won’t have to do it again,” he adds. “If revision surgery is necessary, it is easier to do on the partial knee and is better than doing a second total knee placement.”
