Repaired: Via arthroscopic surgery, the left knee of American Dustin Johnson, according to media reports citing a statement from his management team. The operation to fix damaged cartilage was performed Thursday in Fort Lauderdale, Fla., by Dr. George Caldwell, an orthopedic surgeon who has worked with the Miami Dolphins, Miami Marlins and other sports teams. Johnson underwent a similar surgery on his right knee in late 2011, also by Caldwell. Johnson is expected to return to competition in the fall. Johnson, 35, who is ranked No. 3 in the Official World Golf Ranking, won the WGC Mexico Championship in February for his 20th career title and was runner-up in the Masters and PGA, but he faded late in the season, with no result better than 20th in his last eight starts. Johnson has won at least one PGA Tour title in 12 consecutive seasons.