Partial Knee/ unicompartmental knee replacement (UKR)
There are many different kinds of arthritic conditions that can affect the human body. Osteoarthritis, or degenerative joint disease, is the most common form of arthritis. The bones in a joint are covered with a tough, lubricating tissue called cartilage (the cushion in the joints) to help provide smooth, pain-free motion to the joint. As the layer of cartilage wears away, bone begins to rub against bone (“bone-on-bone”), causing the irritation, swelling, stiffness, and discomfort commonly associated with arthritis.
In some patients, only one part of the knee is damaged, while the remaining parts are completely healthy. In these cases, it is possible to replace only the damaged part of the knee with a metal and plastic implant. With a partial knee, only the damaged cartilage of the knee is replaced. The healthy parts are preserved. In the past decade, there has been a major increase in the use of unicompartmental knee replacement (UKR/ partial knee replacement) as surgical techniques have been refined. UKR has shown to be a reliable operation for isolated unicompartmental arthritis. UKRs now account for 8% to 10% of knee replacement procedures. Recent studies have suggested excellent medium- and long-term results of UKR. Overall, results have shown 85% to 90% survivorship at 10 years, with as many as 90% of patients reporting that they are very satisfied with the procedure and they have reported excellent subjective and objective outcomes. Recent studies suggest that unicompartmental replacement allows a high percentage of patients to return to presurgical sport and activity participation.
UKR has seen a revival in popularity because of the fewer and less severe complications in patients when compared to total knee replacement in appropriately selected patients. Improved component designs and advanced surgical techniques have promoted excellent results. Expanded indications to include the very young and the elderly have also shown similar clinical outcomes. Nonetheless, the success of unicompartmental replacement depends on proper surgical technique and patient selection. Long-term studies have shown that unicompartmental knee replacement is an alternative to total knee replacement.
These procedures can usually be done through a smaller incision and patients generally recover more quickly. Recent research has demonstrated that modern unicompartmental implants, evaluated at a an average of twenty years of follow-up in patients with osteoarthritis that was limited to one compartment of the knee, provided durable pain relief and long-term restoration of knee function without compromising future conversion to conventional total knee replacement. While there are some limitations to what can be accomplished with a partial knee replacement, regardless of its limitations, the functional benefits and lower risks of UKR make it an appealing treatment option for unicompartmental disease.
Dr Donald W Hohman MD is a fellowship trained orthopaedic surgeon specializing in total joint replacements of the hip and knee. Dr Hohman sees patients in the greater Dallas area with office visits available in Dallas. If you have any further questions, he can be reached at 214-252-7039- feel free to utilize the educational material available through the web site www.GDOrtho.com or social media outlets.