Diagnostic Dilemma: Testing to Differentiate UCL Sprains From Flexor-Pronator Elbow Strains in the Overhead Athlete.

Elbow joint injuries continue to increase in frequency in baseball at all levels. It is the most commonly injured joint in professional baseball and approximately 25% of all Major League Pitchers have had a ulnar collateral ligament (UCL) surgery and approximately 30% of Minor League pitchers. Injuries to the elbow joint are increasing in scholastic and youth baseball players too. Often the differential diagnosis between UCL injuries and flexor/pronator tendinitis is difficult for the clinician. The purpose of this commentary is to describe the clinical thought process used to assist in making an accurate differential diagnosis between a UCL sprain and a flexor-pronator strain. The clinical examination description that follows is not meant to be comprehensive but instead will focus on the elements germane to differentiation between UCL and flexor-pronator issues. # Level of Evidence 5.