PERTHES DISEASE
PATHOGENESIS : Vascular supply of Femoral Head by 3 Arteries (At 4 mn of age): Metaphyseal Vessels Lateral Epiphyseal Vessels in the Retinaculum Artery in Ligamentum teres By age of 4 yrs, Metaphyseal supply diminishes to near zero, and Ligamentum teres artery becomes well developed after 7 yrs. So in between 4-7 yrs, the femoral head is mainly supported by Lateral Epiphyseal vessels which may get compromised by effusion following trauma or a non-specific synovitis. Therefore, h/o Trauma (in50% cases) or Non-specific synovitis (irritable hip) PATHOLOGY : 3 Stages : Bone Death - Following one or more episodes of Ischemia, part of the bony femoral head dies. Looks normal on X-ray, but head stops enlarging Revascularisation and Repair - New blood vessels enter the necrotic area and new bone is laid down on the dead trabecular, producing the appearance of Increased Density on Xray ; Some of the necrotic parts are resorbed and replaced by Fibrotic t
