depends where u studying.
if it's UK, quite hard for non local to get in and training is really long but well respected so u will get a ac position for sure back in sg..if it's Australia, almost impossible to get surgical residency as foreigner now but physician training still quite to easy to get and complete (sg u do till u die).
anyway, now sg no lack of specialist. u come back might have to work as a senior staff registrar for few years before getting ac.