From Lav Patel at KUMC:

After doing some testing at KUMC and reading an article at http://www.dba-oracle.com/t_oracle_index_hint_syntax.htm , it seems like i2b2 oracle index hint syntax is wrong.

Here is what articles says: Also note that of you alias the table, you must use the alias in the index hint: select /*+ index(c cust_primary_key_idx) */ * from customer c;.

I also found this true in my testing.