I posted the following in February, but no replies.  Am reposting with
the possibility that a new reader may have some answers:

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Johnson & Johnson have been tv advertising with frequency their total
knee replacement appliance that has "rotating platform".  Is there a
true advantage of this device over other knee replacement appliances,
or is it simply marketing hype?    Any info containing pros & cons or
neutrality on this would be deeply appreciated.   Aaron in N. Hollywood