Not Your Father's Knee Replacement (p.34)

By Dr. Mark Galland

Many of us remember the late 1980s ad campaign by GM — “This is not your father's Oldsmobile.” Although it was ultimately unsuccessful in encouraging a younger generation to purchase Oldsmobiles (and the brand was eventually discontinued), the phrase itself has become a staple of our culture, indicating that something old and mainstream has transformed to something new and hip.

The same could be applied to recent advances in knee replacement. Perhaps one of the most exciting is the recognition that not all arthritic knees are the same. Even though the basic biochemical and biomechanical processes of degenerative arthritis are similar in all knees, the pattern of wear differs according to predictable, well-recognized patterns. This awareness allows for recent advances in surgical technique that have improved surgical results for patients suffering the ravages of knee osteoarthritis.

Many patients with knee arthritis who fail conservative treatment (weight loss, walking program, anti-inflammatory meds, steroid shots, "joint jelly" shots, braces, etc.) have a new option to traditional total knee replacement. These patients may benefit from a partial knee replacement. A partial, or UNI, only replaces the part of the knee joint that is worn, or bone on bone, leaving untouched those parts of the knee that are still in good shape and unaffected by arthritis — removing 75% less bone than a total knee replacement. Think of the knee as having three compartments: an inside, an outside, and a front compartment for the kneecap. Most frequently, it is the inside compartment that becomes arthritic. As compared to traditional total knee replacement, in partial knee replacement, the incision is much smaller, the hospital stay much shorter, and the recovery much quicker. Many patients only spend a single night in the hospital after surgery – some even return home the same day.

There are many different types of UNI knee replacement prostheses, but the type that has been most extensively used is also (not surprisingly) the one most ingeniously designed – the Oxford, which has the ability to mimic the natural motion of the knee. It is comprised of three parts: a highly-polished cobalt chrome stainless tibial tray (for the shin bone side of the knee); a highly-polished cobalt chrome stainless femoral shell (for the thigh bone side of the knee); and a polyethylene (plastic) liner which slides back and forth and toggles side-to-side between the two metal components as the knee flexes and extends. This may seem simple enough, but this is the only UNI knee component that accurately allows this normal motion and required decades of extensive research and implementation to develop. The ability to restore the normal movement of the knee causes many patients to remark post-operatively "It feels like my knee" – not something one hears from many patients who have had a total replacement (so far engineers, designers, and surgeons have been unable to successfully duplicate the restoration of normal knee mechanics in total knee replacements). The free floating nature of the device also improves durability of the implant. 95% of UNIs implanted are still working well 15 years later.

Not all patients with arthritic knees are candidates for a partial. While it is appropriate for patients with symptoms on the lateral (outside) or the medial (inside) parts of the knee, it is not for those with symptoms on both sides or for those with symptoms "all over the knee," when a traditional total knee replacement may be more appropriate. Others who are not candidates for partials are patients with rheumatoid arthritis or severely deformed knees.

If your knees are aching and you can't sleep, if you can no longer enjoy your favorite activities, or if you are just tired of being able to predict the weather better than the weatherman, consult your favorite orthopaedic surgeon to discuss your treatment options.

Dr. Mark Galland is a Board Certified Orthopaedic Surgeon specializing in sports medicine, practicing in Wake Forest and North Raleigh. He serves as team physician and orthopaedic consultant to the Carolina Mudcats, AA Affiliate of the Cincinnati Reds of Major League Baseball, as well as several area high schools and colleges. Dr. Galland is one of the few surgeons in the Triangle region who is trained in the Oxford Unicompartmental (partial) knee replacement and has extensive experience with its use. Dr. Galland can be reached at 919-562-9410 or by visiting www.orthonc.com or www.drmarkgalland.com.