RedirectMatch 301 /out/link http://www.link.com/?getparam1=something&getparam2=somethingelse&getparam3=more
When you click on mysite.com/out/link it goes to:
http://www.link.com/?getparam1=something/out/linkgetparam2=somethingelse/out/linkgetparam3=more
Basically its replacing the & sign, for the http ‘get’ params, with the /out/link part
Possibly try with the B flag
So you would have
RedirectMatch 301 /out/link http://www.link.com/?getparam1=something&getparam2=somethingelse&getparam3=more [B]