Knee Arthroscopy

Could someone verify the difference between the Tears of the knee

I have alot of Knee Arthroscopy Procedures to code and two offices that have coders for Patients that come in the office

Difference between New Tears and Old Tears
When to code Old Tears and New Tears.
How long does New Tears you can code for
and How long Old Tears
I have searched and got so many answers and I would like to know exactly how to correctly code these.

Also for the girls in the office for Post Ops what icd-9 codes to use for 99024 i have issues with this also.

When to use Degenerative Joint Disease 715.16
Thanks