Abstract
Valgus extension overload syndrome encompasses a spectrum of soft tissue and osseous changes occurring in the elbow of athletes participating in throwing or overhead sports, with manifestations varying by skeletal maturity. The three main components of valgus extension overload at the elbow are medial tensile stress, lateral compressive forces, and posteromedial shear, collectively known as thrower's elbow. Significant valgus stresses are placed on the medial elbow during the late cocking and acceleration phases of throwing. Understanding the biomechanics of the throwing motion is essential to recognize characteristic adaptive changes occurring in the throwing athlete and identify typical injury patterns occurring in the medial, lateral and posteromedial elbow as a result of repetitive valgus overload. It is imperative to recognize the full spectrum of injuries that can occur from valgus extension overload in the skeletally mature and immature throwing athletes for accurate diagnosis, effective clinical management and informed return-to-play decisions.