Powershell is smart enough to find the argument as long as it's not ambiguous. For instance:

    Remove-Item -r -fo ./path/to/some/directory

Powershell is smart enough to know that -r means -Recurse and -fo means -Force because the Remove-Item cmdlet has no other parameter that starts with -r. For -f there are two possible arguments: -Filter and -Force which is why you need to be more specific with -fo.