FIGURE 121.9 Avulsion of the inferior pole of the patella in a 10-year-old child with SindingLarsen–Johansson disease Little Leaguer Elbow Little Leaguer elbow refers to a group of disorders resulting from repetitive valgus stress applied to the skeletally underdeveloped elbow The cause of these injuries is multifactorial and includes the number of pitches thrown per outing, the number of outings, type of pitches thrown, throwing technique, and degree of skeletal maturity Valgus force places tension on the medial collateral ligaments, which is translated to the medial epicondyle A medial epicondylitis or apophysitis is the most commonly resulting lesion An avulsion fracture of the medial epicondyle may result from an acute valgus force once the site has