A 23-year-old woman developed rheumatoid arthritis (RA). The pain in her right knee was aggravated and anti-tumor necrosis factor (TNF)-α therapy was selected at the age of 35. The range of motion and Larsen grade were 5º to 120º and 4, respectively. Infliximab and etanercept therapies were quite effective and the pain of the right knee improved. An X-ray at 1 year showed radiographic healing phenomena that included reappearance of a clear visible cortical plane, partial filling-in of erosions and cysts, and sclerosis of the subchondral bone. An X-ray at the age of 43 showed that the radiographic healing phenomena were still preserved after 7 years. The right knee remained pain-free although the Larsen grade was still 4, and the knee function was preserved for 8 years. In conclusion, anti-TNF-α therapy may preserve knee function with radiographic healing phenomena and prevent total arthroplasty of severely erosive knees in young RA patients.