Problem Description

 
The SharePoint Health Analyzer detected an error. Content databases contain orphaned items.

In some situations, a content database that is used by Microsoft SharePoint Foundation, may become corrupted. The corrupted database may contain orphaned items. For example, a document may not have a parent document library or a list may not have a parent Microsoft SharePoint Foundation Web site.  Consequently, you may be unable to create new items with the same URL as the orphaned items, and space in the content database will be consumed unnecessarily.

Error Message: Content databases contain orphaned items

Resolution

Perfect article provided by Microsoft on this which helps me to resolve this issue:
http://technet.microsoft.com/en-in/library/ff805076(v=office.14).aspx