Title children's book from the 50s - possibly earlier?

[lifestooshort123]

Hi, I'm in my late 60s and have a bit of a selective memory these days. I'd love to reread a book I remember from my childhood if anyone can help me identify it please? All I can remember is the chapter where the eponymous heroine is confined to bed with a debilitating illness and, while coming to terms with the disability possibly being permanent, finds she can communicate with the boy over street by means of sending messages along a wire/string between their bedrooms. I believe there was a Grandfather in the house (or am I muddling that with Heidi?) and I think the book had a happy ending. It was also probably set in America. I feel a bit foolish as I'm fairly sure it is a well-known book but I can't quite grasp the title! I'd be eternally grateful for any help, TIA.

It’s not Pollyanna, is it? I can’t lay my hand on a copy and I don’t specifically remember the messages bit, but I know she has an accident and is confined to bed. ( Author Eleanor Porter).

Thank you, it could well be and I'll check. I've posted this on Chat as well (not techie enough to move it) and What Katy Did was suggested. I will get them both on my Kindle and love reading them. It's a pesky nuisance when names suddenly drop through a hole never to resurface - I feel like banging my head on the wall sometimes. Thank you.

I don’t think it’s What Katy Did. She is disabled after an accident (though she later makes a miraculous recovery)but there’s no boy next door in the Katy books. She’s far too virtuous! In What Katy Did at School some of the naughty girls exchange messages with the boys in the college next door, but not Katy.

Perhaps the title will come to me if I stop thinking about it!

Sorry if you already found the answer. ....marianne dreams?

Did you ever find this out? It sounds a bit like ‘Jack and Jill’ by Louisa May Alcott.