For three years a 31-year-old woman has been complaining of pain and swelling of her radiocarpal and metacarpophalangeal articulations, their reduced mobility in the morning, which persisted up to 1,5 hours. Two weeks ago she developed pain, swelling, and reddening of her knee joints, her body temperature increased up to 37,5oC. The treatment was belated. Examination of the internal organs revealed no pathologic alterations. Diagnosis of rheumatoid arthritis was made. What alterations are the most likely to be visible on the arthrogram?