Usually, bow legs do not cause discomfort or pain in young children. However, if the condition does not correct itself, it can lead to symptoms such as: An obvious gap between the knees when standing with the feet together. A gap that persists or worsens past the age of 3. Knee or hip pain that is not related to an injury. Reduced range of motion in the hips. Difficulty walking or running. Instability in the knee.