I am going to apply for TDIU through my VSO. I am currently rated at 60 percent. I have disabilities that keep me from gainful employment based on my career field law enforcement. I have arthritis in both knees to include total right knee replacement. I am filing for back issues secondary to my knees which are service connected. I have had 3 back surgeries. I want to know if my chances are good. Thanks.
If you are rated at 60% for multiple ratings you aren't eligible for TDIU. You need a single 60% rating or multiple ratings adding to 70% or you must apply for an extra schedular rating. To receive an extra schedular rating isn't a simple process. Proving that a back injury is service connected as a secondary condition to service connected knee conditions isn't easy to prove and will usually require an IMO by a credible physician who has a lot to work with in your medical records. If your medical records are scant and don't have much to support your theory that your back is secondary to your knees VA isn't very likely to accept your claim.
I don't usually make predictions of success but in this case you are applying for a benefit you probably aren't technically eligible for and you're making a claim that is very difficult or almost impossible to support. I think you know how I feel about your claim. Good luck sir.