I get many requests for consultation on line and I try to respond at least by email to every one. Many people provide very limited information about their condition(s) so it is always hard to reply. The first thing I look at is how old the person is. It is perhaps the single biggest factor at the initial level. If you are under 40 just expect to be denied at least at the initial level. Don't give up necessarily, but just expect that to happen. This is a typical response to someone who has knee problems and problems with one arm.
A couple of things based on the very limited information you provided:
1) You are very, very young to get approved. You have to prove that there is no job in the national economy you are capable of doing – for example, there are jobs sorting potato chips off of a conveyor belt where you can sit/stand at will all day and only use one arm. So if you have no trouble with your back, legs and other arm, you will be denied.
2) If you have been working in California, State Disability is available to you. It lasts up to 12 months. You can apply on line http://www.edd.ca.gov/disability/SDI_Online.htm It pays about 66% of your wages. State Disability is not hard to get. All you need is a doctor's signature indicating that you've not been able to work for 30 days.
3) Typically, conditions like yours will improve over time. State Disability covers 12 months. Social Security Disability (a federal program) requires the condition you have to last at least 12 months.
4) Under the Social Security Act, you can combine problems. Lots of people tell me about what their main problem is, and don't think about other things. If you have no other physical or mental problems that could be considered in addition to your knees, you will be denied.
5) If you think that you are not going to ever return to a job where you sit most of the day, contact CA Department of Rehabilitation http://www.rehab.cahwnet.gov/Vocational-Rehabilitation.html They will help re-train you so you can find a job that your are physically & mentally capable of doing.
6) If you worked in California and your arm got worse because you were working, it may be a good idea to consult with a Workers Compensation attorney. I have no idea how any of that works. I do not handle Work Comp cases.