Ordering SQL Server results by IN clause

I have a stored procedure which uses the IN clause. In my ASP.NET application, I have a multiline textbox that supplies values to the stored procedure. I want to be able to order by the values as they were entered in the textbox. I found out how to do this easily in mySQL (using FIELD function), but not a SQL Server equivalent.

So my query looks like:

Select * from myTable where item in @item

So I would be passing in values from my application like '113113','112112','114114' (in an arbitrary order). I want to order the results by that list.

Would a CASE statement be feasible? I wouldn't know how many items are coming in the textbox data.