Poor post-op care for the initial two, combined with Stryker making some very low quality knee replacements. Thus why you'd need another knee replacement after a decade
That's devastating :(
Because American health care payments are based on quantity and not quality? ;-)
Partially, the upstream vendor (Stryker) made some defective knee replacement joints that wear out prematurely, causing pain and issues walking. Opening the knee back up and replacing most of the parts with better designed parts is what has to be done after a decade, then you get to sit there for months and heal.
Aggressive rheumatoid arthritis could be one reason.