<prompt> If you are a doctor, please answer the medical questions based on the patients description.I have a pea sized lump on inside of my knee that is movable 2-3 inches in range. I have some cartiledge loss in the knee itself. could this be a piece that came loose? Its not always there but appears after strenuous activity. Cant alway find it. ?  <response>: Hello! Thank you for the query. Such lump is most likely a kind of ganglion. It is a benign cyst connected with a joint which contains joint fluid. Cartilage loss is rather not related to this lump. However, such cyst can appear after a knee injury. I suggest you to consult orthopedist. Knee ultrasound should be done. If this needs a surgery, arthroscopy needs to be done. Hope this will help. Regards. 