Pellegrini-Stieda syndrome refers to the presence of characteristic medial knee pain in the presence of previous medial collateral ligament injury and a Pellegrini-Stieda lesion (most of which are asymptomatic). It is named after Italian surgeon Augusto Pellegrini (1877-1958) and German surgeon Alfred Stieda (1869-1945).
The injury is generally sustained as the result of a strike or unnatural stretch in the area where the medial collateral ligament joins to the femur. A significant direct blow can often be sufficient to provoke the condition. High speed impact from a cricket ball, football or other projectile is a common cause, as is a severe tackle or similar strike during a contact sport. Pellegrini-Stieda syndrome can also be caused by stretching the muscle incorrectly, especially due to a specific fall.
Standard anteroposterior xray would show a linear soft tissue opacity medial to the femoral condyle. The linear fashion of ossification is often suggestive of calcification of the proximal aspect of the medial collateral ligament. The calcification may also involve the adductor magnus tendon.