[Knee injury 40 years ago while on Active Duty worth filling claim for?]

I served in the US Army from 1978 to 1982. In 1979 I hurt my knee while on active duty during physical training. It has never been the same since. I have seen my private Orthopedic Surgeon many times and his last diagnosis is a Total Knee Replacement. 

I was able to get a copy of my service medical records and it’s documented in there that I suffered the injury while on active duty and I saw medical personnel for treatment.  I have not submitted a VA claim for this yet. 

Has anyone successfully submitted a VA claim for this type of injury and were you successful in getting it approved? 

I am interested in getting help with my deductible for the surgery, which even with 90% coverage private insurance, I’ll have to come up with $2,500 for my share and the deductible. I am making $13 per hour and live paycheck to paycheck and don’t see myself able to save that amount or am able to get any more loans or credit to do so. 

Thanks in advance 

George M. Jr.