Vail Daily health column: Are you a candidate for partial knee replacement surgery?
February 9, 2015
Question: I have been diagnosed with severe knee arthritis. Might I be a candidate for partial knee replacement?
Answer: Osteoarthritis, or "wear and tear arthritis," is a loss of the articular cartilage or coating cartilage that caps the end of the femur, the top of the tibia and underneath the knee cap. I liken this coating cartilage to the white cartilage on the end of a chicken bone. As this coating cartilage wears away completely, the wear can progress to "bone on bone arthritis," which typically causes severe pain, swelling, stiffness and a feeling of weakness in the knee. In turn, arthritis can limit a patient's ability to participate in the activities that they enjoy, such as skiing or hiking.
NONSURGICAL TREATMENT OPTIONS
Prior to considering any surgery for arthritis, I recommend that a patient exhaust all nonsurgical treatment options. Even with arthritis, many patients can still participate in low impact aerobic exercises such as biking or swimming. They should also do some low resistance, high repetition weight training to maintain strength around the knee. Physical therapy is beneficial. Although less common here in the high country, weight loss is recommended for patients whose body mass index is elevated (i.e. above 25). If the arthritis is confined to one side of the knee, then an unloading knee brace is helpful for most patients, particularly in skiers. Anti-inflammatory medications (topical or oral) can also provide some relief as can an occasional steroid or viscosupplementation injection.
If all nonsurgical management has failed and radiographs and a good physical exam in the office are all consistent with end stage arthritis, then partial or full knee replacement may be warranted. A partial knee replacement is a very good option for active patients with end stage arthritis. However, not everyone is a candidate. To be a candidate for partial knee replacement, the arthritis should be confined to largely just one compartment of the knee. There are three compartments of the knee, namely the medial (or inside) compartment, the lateral (or outside) compartment, and the patellofemoral (or under the knee cap) compartment. Furthermore, patients must have intact ligaments around the knee and cannot have an inflammatory arthritis condition such as rheumatoid arthritis. If a patient meets these conditions, and if their arthritis is largely confined to just one compartment of the knee, then they may be a good candidate for partial knee replacement.
In partial knee replacement surgery, cutting jigs are used to remove a very thin layer of bone and all the worn cartilage on both of the affected surfaces in that compartment and then thin metal and plastic implants are used to resurface these areas. In so doing, the bone-on-bone condition causing the pain is removed such that now there is metal on plastic. These surgeries are now done on an outpatient basis. Patients can walk on their knee right away, although it can take 1-2 weeks for patients to be able to walk comfortably without crutches. Physical therapy is started immediately after surgery to help restore range of motion and then strength. Patients can be riding an exercise bike in the first week, biking outdoors within six weeks and skiing by three months.
Dr. Rick Cunningham is a knee and shoulder sports medicine specialist with Vail-Summit Orthopaedics. He is a physician for the U.S. Ski Team and chief of surgery at Vail Valley Medical Center. Do you have a sports medicine question you'd like him to answer in this column? Visit his website at http://www.vailknee.com to submit your topic idea. For more information about Vail-Summit Orthopaedics, visit http://www.vsortho.com.