Clinical study of baseball pitchers: correlation of injury to the throwing arm with method of delivery

Abstract

Injuries to the shoulder and elbow are common in baseball pitchers,' with the incidence of disability directly related to the duration of exposure and to the intensity of participation. Adams,2 in a study of 80 Little League and Pony League pitchers, 9 to 14 years of age, reported significant problems in 95%, the most common being accelerated growth and separation of the medial epicondylar epiphysis. Torg et al.,' in a study of 49 pitchers 9 to 18 years of age, found that 70% had soreness when pitching, but there were fewer severe problems than in Adams' study. He felt the difference was due to a better attitude since, presumably, his pitchers were less competitive. Only studies performed or sponsored by the Little League have concluded that the incidence of injury is insignificant in pitchers. 1, 4 Professional pitchers uniformly show hypertrophy of the flexor forearm muscles, over 50% have a flexion contracture and 30% have an increased valgus angle compared with the opposite extremity.~ The elbow problems that occur appear to be related to valgus stress as the shoulder internally rotates from a position of maximum external rotation.~ The medial joint structures are subjected to traction, while compression occurs at the radial humeral joint. Separation or fragmentation of the medial humeral epicondyle may develop, with traumatic arthritis or osteochondritis dissecans laterally. In older pitchers osteochondritis of the olecranon (possibly a later manifestation of the same forces) may be due to bony hypertrophy, medial stress, and cubitus valgus. The incidence of shoulder disability appears to increase with age and proficiency. Osteochondritis of the proximal humeral epiphysis has been reported in children, while in older pitchers, tendonitis and muscle strain are more common The exact muscle group involved can often be correlated with the phase of the pitch.8,9 9 At the end of wind-up when the shoulder is extended, abducted, and externally rotated and the body is beginning its forward motion, symptoms may occur at the pectoralis major insertion, the origin of the anterior deltoid, or over the long head of the biceps, which tends to subluxate out of the bicipital groove in this position. During followthrough, the posterior deltoid may be stretched near its origin from the spine of the scapula, and (especially with a curve ball) tendonitis may develop in the long head of the triceps at its origin from the inferior border of the glenoid. In addition, tendonitis of the rotator cuff is increas-

Baseball Injuries

“…Sidearm pitching motion was Fair [20,21,26] associated with an increased risk of elbow pain in a single small prospective study of youth pitchers. No other studies have demonstrated a relationship.…”

“…Overall, the rates of injury in youth and high school baseball are lower than other sports played by children and adolescents, but they still represent a significant cause of injury and potential long-term disability among the participants [18], particularly among pitchers [19][20][21][22][23][24][25][26][27][28].…”

“…Furthermore, continued overuse is believed to eventually result in serious injury or arm-related disability in some pitchers [18]. Table 2 summarizes the findings of studies of elbow and shoulder injury in pitchers published between 1965 and 2002 [19][20][21][22][23][24][25][26][27][28]. In 1965, Adams conducted the seminal epidemiologic study on this issue [19].…”

“…The frequency of arm pain was highest in pitchers. Subsequent studies of American youth and high school players have demonstrated a prevalence of elbow pain between 18 and 29% [22,24,27,28] and an incidence of elbow pain of 26% among youth players and 58% among high school players [20,21,23,25,26]. Shoulder pain has not been studied as frequently with a prevalence of 29% in single study of 9-18-year-old boys [28] and an incidence of 32-35% in two recent studies by Lyman et al [25,26].…”

“…This reduces recall bias in this young population. Radiographic exams were not [20] Conn., USA Hang (1979) [23] Little conducted in this study because previous research had shown no consistent relationship between radiographic abnormalities and arm pain.…”