Preprint policy of majority of academic journals can be found in the Wikipedia: https://en.wikipedia.org/wiki/List_of_academic_journals_by_preprint_policy.
Some 130 journals can be found in the list. Large majority of journals allow preprints prior to submission. Few journals have restrictions. Four journals glow in red since journal policy does not allow preprints. Which journals would they be?
These journals have published a joint statement about their policy. This statement outlines five specific reasons why these journals do not accept preprints. Among other things four Editors conclude:
We believe that the benefits proposed by advocates of medical preprint servers can be better achieved in other ways, and that medical preprint servers pose serious health and safety dangers to the patients for whom are supposed to be caring
Ok then. I guess orthopaedic research is different to cardiology or oncology because leading journals in those fields allow preprints.