Pain in the bony prominence (tibial tuberosity) just below the knee is the most common sign of Osgood-Schlatter disease. Pain may occur in both legs, but is limited to just one leg in about 75 percent of cases. The affected leg is usually the dominant leg used in jumping, kicking or running. In some cases, the knee pain or leg pain is mild. In other cases, it is more severe.

Pain is often felt when the patient extends (straightens) the knee against resistance, stresses the quadriceps or squats with the knee fully bent. Pain may become worse with certain forms of exercise, including running, jumping, and going up and down stairs. Kneeling also may cause pain. In other cases, pain is more constant. In most cases, the knee’s range of motion remains unaffected.

Continued swelling (edema) over the tibial tuberosity may cause a bony callus to form. As this callus grows larger, it may become extremely painful when touched. This enlargement of the tibial tuberosity is likely to remain large throughout the child’s lifetime, even after the child has recovered from Osgood-Schlatter disease and pain has subsided. 

Other symptoms associated with Osgood-Schlatter disease include:

• Limping after exercise or other gait disturbance
• Swelling or tenderness under the knee and over the shin
• Tightness of muscles surrounding the knee