Question:
What is the new knee replacement procedure that is in lieu of full surgery?
Answer:
Newer surgical procedures for arthritis of the knee that have gotten recent press include:
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Unicondylar or partial knee replacement
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UniSpacer
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Minimally invasive knee replacement
The unicondylar knee replacement and Unispacer are not new, but variations on an older theme. Replacing only the portion that is worn was done extensively for osteoarthritis in the past. Those patients who had limited deformity, good range of motion, and low demand on their joints initially did quite well. However, by the second decade of use, the patients who had unicondylar surgery began to need revision (redo surgery) more often compared than those who had standard total knee replacements.
There has been a recent resurgence of the use of unicondylars in younger and younger patients, with the untested expectation that newer materials and techniques will translate to less frequent revisions. The ideal patient for the unicondylar remains the older, thinner patients rather than the younger, more active patients.
Unispacers are very similar to metal disks called interpositional spacers that were placed between arthritic rubbing bones. The metal disk spacers, used in the 1970s, were abandoned when total knee replacement developed and got strikingly better results. In my opinion, the newer Unispacers have not been shown to provide superior long-term results.
Minimally invasive knee surgery is an attempt to do replacements through much smaller incisions to limit tissue damage and decrease pain. This is a developing field with a difficult "leaning curve." The results from studies comparing minimally invasive surgery to traditional knee replacement vary. Some studies show a higher complication rate with minimally invasive surgery, but in other studies the short-term results are similar to traditional knee replacement.
