Microsoft Test Manager (MTM) is forward and backward compatible with TFS.  This mean you can use -

  1. MTM 2010 with TFS 11.  To do so, you need to install the Compatibility GDR.
  2. MTM 11 with TFS 2010.  This is supported without any extra install.

Since many new features require change in both the client and the server, you will not get those with the above combinations.