Valgus Extension Overload

Valgus extension overload is a syndrome of elbow symptoms and pathology common to throwing athletes. The condition is caused by a repetitive valgus force and medial laxity of the elbow leading to excessive shear forces and compression of the articulation between the posteromedial olecranon and the olecranon fossa (Fig. 32.1). Consequently, osteophytic change can occur at the posteromedial tip of the olecranon or in the olecranon fossa in compensation for elbow instability. The presence of osteophytes at this location is the most common diagnosis in professional baseball players undergoing open or arthroscopic elbow surgery. Surgical treatment of valgus extension overload is effective as advances in elbow arthroscopy instrumentation and technique continue to evolve. The excessive forces to which the elbow is exposed during the throwing motion comprise 64 Nm of valgus stress during the late cocking and acceleration phases, 300 N of medial shear force as the elbow extends at over 2300°/s during the acceleration phase and 900 N of lateral compressive force during the deceleration phase [1].