**6.1 Roentgenogram**

Anteroposterior, lateral and tangential views of patella may show radiolucency over involved pole in early stage, while in prolonged stage, the involved pole may appear elongated. In chronic cases tendon calcification and periosteal reaction over anterior aspect of patella ("tooth sign") may be evident. While in long standing cases the stress fracture or disruption of extensor mechanism may occur.
