I have come across a few patients recently where their knee arthritis was so severe and has gone on so long that their legs have become severely deformed. In these cases, standard knee replacement implants will not work properly. The ligaments that hold the knee in place can get stretched out in severe cases and when the deformity is corrected and the leg is straightened, the ligaments become incompetent.
In these cases, a constrained type of knee replacement implant must be used. Constrained implants have larger internal supports that hold the implant together and have stems or rods that anchor the implants deep within the bone so that they can absorb the increased forces necessary to hold the knee together. I personally use the
Zimmer NexGen LCCK system for these cases.
Here are before and after radiographs (x-rays) of a recent case:
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Severely bowed knee with advanced arthritis |
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Post-operative x-ray showing knee replacement with constrained LCCK implants. |
As you can see in the second set of x-rays, the angulation (deformity) has been corrected with this stemmed implant. It has been one month since surgery and he is doing exceedingly well.