When you file a UI claim, most states ask if you are able to work and available to work. If you aren't able to work and available to work then your UI claim is forestalled until you are able to work and available to work.
If the surgery was due to working conditions you might be eligible for workman's compensation, but this is not the same as unemployment. To be eligible for unemployment, you have to be ready, willing, available and ABLE to work, and if you said you could not work, then you are not eligible.
If the injury occurred while on the job, you probably are eligible for Workers Comp. Whether not being able to work, otherwise, the claim would depend on the rules of your state's employment security office.