I don't think they really have access to post-revolution medical knowledge.
They have. If you can read spanish, take a look at this book, around page 293. If you can't read spanish, this the end of Castro's quote: "And our country adopted, in fact, the decision of abolishing intelectual property." This was decided in the context of ensuring that students and researchers had access to the literature.
Not all cubans can afford or are allowed (embargo) to pay for modern books. But not all cubans have to: once the book is acquired, it can be photocopied legally... in fact, the government will photocopy the textbooks and loan them to the students "for free" (you pay only if you don't return them at the end of the school year).
It's not like they can go to pubmed or something.
Ironically... the cuban "ISP" with most home users, Infomed, was created to facilitate access to information to doctors and health professionals. Nearly every doctor can get a free dial-up account with Infomed. This includes retired doctors. I quoted "ISP" because they only give access to email and some whitelisted sites... pubmed is among them.
(Source: I used to be an Infomed suscriber. I am not a doctor, but there are doctors in the family. They still use Infomed.)