I'm not sure where you live, but it is my understanding in the US (I could be wrong, if I am, someone correct me) you don't have to disclose health conditions in job interviews, and it is discriminatory for the interviewer to ask about health problems in the interview that are unrelated to the job function. In the US, prospective employers aren't supposed to ask questions about health matters, national origin, marital status, sexual preferences, any of that stuff. Interviews are supposed to be about your qualifications, your experience, your work history, your ability to do that job, what you can bring to the company, etc. That, and whether you are a citizen or have a green card if you're not. That's basically it. A good prospective employer isn't going to care about anything else. Some people, seeing a limp, might think you recently hurt something and ask you what happened. Technically, they shouldn't ask that question in an interview, but they may do it without thinking. You can just shrug and say you have a problem with your leg and let it go at that. In the job interview stage, it is none of their business.
It may help you to consult for an hour or so with an attorney specializing in labor law, employment discrimination, and disability issues to get the do's and don't's on what you are legally required to discuss in a job interview so you can approach your interviews with confidence and focus on the important issues relating to the job function, which for a finance job doesn't include your limp. You aren't applying for a physically demanding job you know you wouldn't qualify for, like a fireman or something. I don't know if you have any special need, like an eyesight problem that would require a workplace accomodation, a reduced work schedule, etc and what you are legally (and reasonably) required to disclose about that up-front in an interview. An attorney could answer that. You have a visible limp, so do a lot of other people, and limps are caused by a lot of things. I sometimes limp because I have an old meniscus tear in one knee that can't be fixed. If you had diabetes, or arthritis, or nerve damage from a car accident, etc., you wouldn't feel compelled to offer that condition up, so don't offer MS up either just because you limp. You have got an employment track record, you lost your old job (so do a lot of people) and you went out and scored contract work, so you can show you can still work.
Once you GET the job, then, as part of you applications for health insurance or other benefits, that is when the health disclosure issues do come in. The employer may react negatively to that, but the ball is in the employer's court, not yours. You showed the employer you had the right qualifications for the employer to hire you, you get in the door and start doing the job. If the employer starts treating you unfairly once you're in, then the law is on your side, although it won't be a place you would want to work in anyway, and probably isn't a good place for any of the other employees, either.
Good luck job hunting!