Give them a call!
I don't know.

Regardless, it can be fixed later if necessary. Just concentrate on healing.

They would have told you before you had surgery if there is ANY problem with your medicare. And, yes, it's the number that matters the most.
Be at peace, my friend! No need to stress!

and it's never been an issue. When ever I have to call them (and it's been a lot), they ask me to state my birthdate, SSN, and address to verify my identity. No problem!

Or did I miss a post?

My card has my first name, middle initial, last name. Some other documents like my drivers' license include my full middle name but I've never had any problems with identification with any of them.

My healing environment is not the greatest

Your MBI number, name, and date of birth all have to match the data in the CMS database . I have seen exceedingly few claims denied for missing or mismatched middle initials. It might happen, however, if someone with your exact name has your exact birthdate. Then your middle initial might be appended to your first name e.g. Smith, Mary E instead of Smith, Mary. But most providers who are interested in getting paid be aware of these quirks in the system and make sure your data matches Medicare’s records.

I'm convinced, by the expertise above, that the number is all that matters. That, plus you confirm date of birth at the provider.