I hurt my knee and took an X-ray. Why is there a white circular spot on the femoral head? Is it normal? Is it serious?

From the X-ray positive film of the knee joint, we can see that there is a small piece of high-density shadow in the lower femur with clear boundary, which should be considered as an island at first. This is a kind of bone variation, which mostly occurs in femur, ilium and vertebral body. Dense bone mass or nodule appears in cancellous bone. Gudao is not a disease, don't worry, and don't need treatment.