The doctor told me that I need to lose weight and that the problem might be genetic concerning my knee. He would not perform an Xray.

From what you have written I gather that you are wondering whether you have a viable malpractice case against the first physician you so who failed to diagnose an injury to your name. I think the answer is probably no because although there was a delay in diagnosing injury you will eventually receive the treatment you need and presumably you won't suffer from lasting harm as a result of the delayed diagnosis. Click here for an article that discusses the three main questions I ask when deciding whether to investigate a potential medical malpractice case.