Thanks for writing to us.
should be immobilised, whether it is hairline one.If proper immobilization is not given, it will hamper the healing process.
Wound over your hand also need dressing.
So it is better to follow advice of your orthopaedician.
I hope this answers your query.
In case you have additional questions or doubts, you can forward them to me, and I shall be glad to help you out.
Wishing you good health...
Dr Saurabh Gupta.