Thanks for your question and I'm sorry to hear about your situation.
If your ACL tear occurred while you were at work, then the medical treatment should be covered by workers comp. Further, you should be receiving temporary income benefits while you cannot work, especially where you have been allowed to return to work on light duty, but your employer has not made any light duty work available to you.
Since you have filed a workers comp claim, you need to contact the following:
Request for a Hearing
Melinda Poppe, Claims Manager
Phoenix: 800 W Washington St, Phoenix AZ 85007 - Phone: (NNN) NNN-NNNN
Tucson: 2675 East Broadway, Tucson AZ 85716 - Phone: (NNN) NNN-NNNN
FAX (use for either office): (NNN) NNN-NNNN
This is so that you can request a hearing. At the hearing you will tell the judge exactly what is going on and ask that they pay for your surgery and pay you the income benefits you are owed.
Sedgewick is a bad company. It may be a good idea that you call a workers compensation attorney to help you with this. Google "workers compensation attorney" and the name of your city to find a local attorney to help you. They will take your case usually without charging you anything.
It really is as simple as that. Your workplace injury entitles you to payment of medical treatment needed for the injury and income benefits while you cannot work, or if they do not have light duty work for you.
Please let me know if you have further questions.