Unresolved How to Fix Orientable: No - Netfabb

Hi all,

I am a student, with low-budget software (i.e. the Basic version of Netfabb + Meshlab). One of my long term projects has been to 3D print a model of the hip joint. I’ve have acquired access to CT scans in .dcm files, which I have surface rendered in OsiriX and later exported to a STL file, to open in Meshlab. In Meshlab I did some touch-ups to the surface rendered hip joint, however I noticed some gaps and holes in the actual surfaces (attached). With my very limited programming experience I am the DEFINITION of a noob with 3D software. After researching how to get it ready for 3D printing I realised that through Netfabb I had to Repair the model. I did this with the appropriate steps but, and I then applied a Standard Analysis, but it says:
“Surface is closed: Yes
Surface is orientable: No”
Any clue on how to fix this? I cannot afford Netfabb Pro; I’m attempting to survive on Basic. What did I do wrong?! Suggestions are much appreciated.

Cheers, Tiana