IANAL, but I've spent some time on these topics, and in the end the only thing that matters is the result of some court case. But non-authoritatively:
It seems to me that if you were willing to go to court and defend yourself, you'd have a very strong case that posting your review is covered under fair use. Of the four factors of fair use testing [1] (which is to say, I'm talking about real fair use and not the nebulous Internet "I can do whatever I want with whatever I want if I just say the magical words 'Fair Use'" version), the purpose of the use and nature of the work are probably solidly on your side, and there is definitely no damage to the market value of the work (bearing in mind that refers to the value of the review itself, not any effect it might have on the doctor's practice), to the extent that I can say "definitely" without a legal ruling. The problematic case is that you'd be posting the totality of the work in question but I suspect it would not be hard to find a judge that would still agree that your First Amendment rights overrule that concern, especially given that we're talking about a commercially effectively-worthless work and it's not very large.
I'm not sure fully owning the copyright is really enough to prevent people from posting a review. I also would imagine a strong case could be made for even going back behind the standard 4 fair use factors and returning to the reason they were created in the first place, which is that while the Constitution grants Congress the right to write laws about copyright, free speech is in the First Amendment and where there are conflicts, the amendment wins, at least in theory. The fair use tests are intended to harmonize the two. Use of copyright as a speech restraint is a fundamental perversion of the whole system, not just morally (which doesn't really matter to this analysis) but legally.
I speak solely on the matter of copyright assignment; if the contract contains other non-copyright restrictions on posting reviews I have no opinion at all, even if I could see them. I am also not addressing the possible ways in which this could be considered an invalid contract clause in general, such as [2].
It seems to me that if you were willing to go to court and defend yourself, you'd have a very strong case that posting your review is covered under fair use. Of the four factors of fair use testing [1] (which is to say, I'm talking about real fair use and not the nebulous Internet "I can do whatever I want with whatever I want if I just say the magical words 'Fair Use'" version), the purpose of the use and nature of the work are probably solidly on your side, and there is definitely no damage to the market value of the work (bearing in mind that refers to the value of the review itself, not any effect it might have on the doctor's practice), to the extent that I can say "definitely" without a legal ruling. The problematic case is that you'd be posting the totality of the work in question but I suspect it would not be hard to find a judge that would still agree that your First Amendment rights overrule that concern, especially given that we're talking about a commercially effectively-worthless work and it's not very large.
I'm not sure fully owning the copyright is really enough to prevent people from posting a review. I also would imagine a strong case could be made for even going back behind the standard 4 fair use factors and returning to the reason they were created in the first place, which is that while the Constitution grants Congress the right to write laws about copyright, free speech is in the First Amendment and where there are conflicts, the amendment wins, at least in theory. The fair use tests are intended to harmonize the two. Use of copyright as a speech restraint is a fundamental perversion of the whole system, not just morally (which doesn't really matter to this analysis) but legally.
I speak solely on the matter of copyright assignment; if the contract contains other non-copyright restrictions on posting reviews I have no opinion at all, even if I could see them. I am also not addressing the possible ways in which this could be considered an invalid contract clause in general, such as [2].
[1]: http://fairuse.stanford.edu/Copyright_and_Fair_Use_Overview/...
[2]: http://en.wikipedia.org/wiki/Unconscionability