that effusion (fluid) could be olecranon bursitis but there can be many different reasons for having an elbow full of fluid. my advice to you is to see an orthopedist. and expert in this area. so that you can be properly evaluated.
i have a very swollen elbow. it feels like a water baloon full of liquid. range of motion is uninhibited. pain now. . i have hiv/aids. seems. like a bursitus. i fell and landed on my elbow 4 mos. ago.