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Elbow Injuries in Young Baseball Players

James A. Whiteside, MD; James R. Andrews, MD; Glenn S. Fleisig, PhD

Controversies Series Editors: Marc T. Galloway, MD; Barry Goldberg, MD

THE PHYSICIAN AND SPORTSMEDICINE - VOL 27 - NO. 6 - JUNE 1999


In Brief: The demands that throwing places on the vulnerable immature elbow frequently produce multiple injuries. Significant clues in the history include persistent medial elbow soreness, stiffness, and discomfort that lead to poor performance. Diagnosis involves identifying the injury sites by palpation and x-rays that pinpoint growth-plate separation or osteochondral changes. Nonoperative treatment, which can proceed if growth-plate separation at the medial apophysis is less than 3 mm, involves stretching, strengthening, sport-specific activities, and interval throwing. Prevention includes conditioning, limiting the number of pitches, and using age guidelines for learning new pitches.

Baseball is one of the most popular sports for children, but repeated throwing, especially pitching, in skeletally immature athletes can produce elbow injuries that threaten the growth plate. Physicians who care for youth league pitchers and their teammates can expect to be kept busy treating these injuries; a recent survey found an injury incidence of 40.1% in 172 9- to 12-year-old pitchers who were followed for 1 year (1). Physicians who understand the injury mechanics and pathologic consequences are better equipped to help the young athlete prevent injuries, advise parents about pitching training for children, and identify the early signs of injury.

Injury Mechanisms

The elbows of skeletally immature patients have secondary ossification centers at the distal humerus, radial head, and olecranon. When subjected to repetitive stress, such as frequent overhand throwing, the growth plates (physes) of these unfused centers are more vulnerable to injury than are the adjacent muscle-tendon units.

Overhand throwing subjects the elbow to forces of tension, compression, shear, and torsion (figure 1). The acceleration phase of pitching or throwing hard with a flexed elbow places a valgus stress on the medial ligamentous support structures and the ulnar nerve and compresses the lateral osseous anatomy. Posteriorly, valgus torque causes the medial part of the olecranon to impinge against the medial olecranon fossa. Anteriorly, the distal bicipital tendon stretches eccentrically when the forearm extends after ball release.

[Figure 1]

The primary ligamentous stabilizer of the elbow in a thrower of any age is the anterior bundle of the ulnar collateral ligament (UCL) (figure 2) (2). The UCL in skeletally immature athletes is attached proximally to the extra-articular, unfused medial humeral apophysis and distally to the sublime (elevated spot) tubercle of the ulna. Direct trauma or a posterior elbow dislocation infrequently avulses the medial humeral apophysis. More typically, chronic, subclinical valgus distraction partially separates the medial apophysis from the humerus (Salter-Harris type 1 fracture). With repetitive valgus stress, a single hard throw may partially or completely avulse the medial apophysis from the epicondyle. In this case, the UCL remains intact, but it is incapable of providing medial support. When the medial apophysis is solidly fused, a single hard throw may precipitate flexor/pronator muscle strain and, with similar repetition, UCL pathology.

[Figure 2]

In 1889 König (3) recognized a lesion of the subchondral bone in the capitellum and radial head and named it osteochondritis dissecans. A comparable lesion in 7- to 11-year-olds was described by Panner (4) in 1924 as osteochondro-sis of the capitellum. The distinctive feature of Panner's osteochondrosis is that stopping the offending activity, such as pitching and hard throwing, allows the lesion to heal without loose-body formation.

In 1960 Brogdon and Crow (5) observed that in young pitchers, repetitive valgus microtrauma produced medial apophysitis; they labeled the condition "Little Leaguer's elbow." (To avoid negative connotations, Little League Baseball, Inc, has requested that the term "Little Leaguer's elbow" not be used in this article. Consequently, "elbow injuries in the physically immature" is substituted.) Other authors have expanded this primary entity to include (table 1):

  • partial or complete avulsion of the medial apophysis,
  • articular cartilage and subchondral bone changes in the lateral capitellum and radial head (ie, osteochondritis dissecans),
  • avulsion of the posterior olecranon epiphysis from valgus extension overload,
  • stress fracture of the proximal ulna, and
  • ulnar nerve neuritis medially.


Table 1. Elbow Injuries in Young Throwing Athletes


Anterior Compartment
Anterior capsular stretching
Bicipital tendinitis
Biceps and/or brachialis muscle weakness
Osteochondritis dissecans

Lateral Compartment
Extensor and/or supinator muscle strain
Lateral apophysitis
Anconeus muscle strain
Suprachondral fracture

Posterior Compartment
Olecranon tip impingement
Olecranon apophysitis
Triceps tendinitis

Medial Compartment
Ulnar collateral ligament sprain
Flexor and/or pronator muscle strain
Medial apophysitis
Partial or complete avulsion of the epiphysis
Ulnar nerve neuritis


Typically, these repetitive excessive forces involve the hypertrophic zone of the growth plate, which is particularly vulnerable during peak growth velocity—ages 10 to 12 for girls and ages 13 to 15 for boys.

In 1968 Slocum (6) was the first to note that in young pitchers, compression, rotational shear, and extension forces produce articular cartilage and subchondral bony lesions in the capitellum and radial head. (See "Osteochondritis Dissecans of the Elbow: Diagnosis, Treatment, and Prevention," February, page 75.) These lateral osteocartilaginous lesions may be augmented by inherent or acquired elbow laxity, relatively small surface compression areas, or vascular insufficiency. The lesion in the capitellum resembles avascular necrosis.

Nerve entrapment injuries also can occur in throwers. The ulnar nerve can be injured from stretching in the groove, the median nerve from volar forearm compression forces, the radial nerve from supination, and the musculocutaneous nerve from pronation and extension.

Medial elbow pathology in young baseball players is often attributed to overuse, which implies that the actions exceeded the expected volume. However, the term "overuse," used in this way, implies that the solution to youthful pitching injuries is simply for players to pitch and throw less. This is an oversimplification. Prevention and treatment of these injuries must take into account not only the number of pitches or throws and the frequency of play, but also velocity, throwing mechanics, and the player's age.

Typical History

A carefully directed history is the essential prerequisite and complement to a thorough physical examination. Usually, young players report that the medial elbow and proximal forearm began to hurt a few days either after repeated throwing to first base from third or shortstop or after pitching. Initially, they recount that the discomfort abated with rest but returned during throwing. Unlike skeletally mature athletes, younger players often do not recall a single pitch that caused the pain. Rather, medial symptoms occurred after multiple hard throws or pitches over a short time. These young athletes are often the best "skill" athletes on the team, and when not pitching they usually play third base or shortstop. They may say that hurried throws from third to first base produced shoulder or elbow symptoms that were not evident during pitching.

Young throwers may not recognize or understand the importance of reporting minimal arm symptoms early. They may consider arm fatigue, which is the first indicator of impending injury, normal after pitching a few innings and then playing third base. Local soreness on the palmar surface of the proximal forearm soon follows arm fatigue. Some arm soreness may not be unusual after playing, but more severe pain that persists the next day is pathologic. When expected to start the next day at third base, for example, players are conscious of elbow stiffness and soreness and have trouble "getting loose." Also, athletes may report that their throwing was somewhat errant and produced even more symptoms.

Patients seek medical help when they realize that medial elbow pain impairs throwing and batting performance. Young ball players, compared with older players, often do not report prodromal symptoms unless specifically quizzed. Coaches and parents can help prevent more serious injuries by investigating when players exhibit abnormal mannerisms while fielding, throwing, or batting.

Physical and Radiographic Examinations

In classic elbow injuries in young baseball players, clinical findings reflect defects in the interval between the distal humerus and the medial apophysis. Medial tenderness is often evident when the UCL is placed in a valgus stretch. Palpation of the flexor-pronator muscle mass on the volar aspect of the proximal forearm may produce diffuse medial pain or discomfort because the musculature is often strained when it acts as a secondary support to an injured, failing UCL. In this situation, the neurovascular exams of the elbow, shoulder, forearm, wrist, and hand are usually normal. Other physical exam findings may include minimal swelling of the forearm and pain with resisted pronation.

Anteroposterior, lateral, and right and left oblique x-rays are needed to confirm the diagnosis and extent of osseous injury. The degree of medial apophyseal separation from the distal humerus can be measured by comparing the x-rays of the injured limb with those of the asymptomatic side. X-rays can reveal changes in the lateral capitellum and radial head and alvulsion of the olecranon, and they can document ulnar stress fracture and physeal involvement.

Treatment and Rehabilitation

Regardless of pathology, the clinical diagnosis of injury to the physically immature athlete's elbow and its delayed recovery portend a considerable loss of playing time. Players who have separation of the medial apophysis should not pitch the rest of the season but may play first base or another throwing position later in the season.

Nonsurgical treatment involves immediately stopping play, initiating anti-inflammatory medication, and beginning structured rehabilitation to ensure full recovery. Icing of the medial elbow should begin immediately and should be done for about 15 minutes three or four times each day. Electrical stimulation can be ordered at first to relieve pain, and later to avoid muscle contraction. In the rehabilitation program, patients progressively stretch the involved area through its full range of motion three times a day to regain full motion while protecting the primary injury site (7).

If conservative treatment fails, surgical intervention usually involves pinning the medial apophysis if separation is greater than 3 mm and wiring if avulsion of the triceps-olecranon complex is significant.

The rehabilitation program is individualized, but athletes who have significant UCL sprains should not play or bat for 6 to 8 weeks, during which the patient undergoes daily rehabilitation activities. Trainers can help determine a player's progression during rehabilitation. Patients begin strengthening with light weights, then progress to isometric and isotonic exercises. Curls and extension exercises are performed for biceps and triceps muscles, pronation and supination exercises for forearm muscles. (Shoulder strengthening exercises should also be included.) Once full pain-free range of motion is established and strength has returned to preinjury levels, sport-specific exercises are started.

One of the most useful exercises for pitchers is an interval throwing program that initially utilizes the long overhand toss (8). The toss distance is decreased by increments as the velocity of the throw is increased. When players are comfortable throwing 45 feet at 50% velocity, they advance to throwing in the bullpen, then off the mound at full effort. A similar program, minus the pitching element, is used for other throwers. Physicians base the return-to-play decision on the physical therapist's report that the young athlete has established good control and is pain-free at full velocity. Follow-up radiographic studies can be used to guide the return-to-play decision when treatment is conservative. If the medial apophysis is off 1 to 2 mm, repeat x-rays will remain the same until physes close. Radiographs are always used for follow-up after surgery.

The likelihood of injury recurrence is diminished by obtaining full range of motion and strength and then progressing in a graded, sport-specific fashion while maintaining rehabilitation protocols.

Prevention Measures

Prevention is the responsibility of all who are concerned with youth baseball, although it has been the subject of little clinical research. Several important factors contribute to the youthful pitcher's ability to perform well and remain injury free. Initially, the athlete needs to be healthy and eager to participate. Daily stretching and conditioning are needed to ensure athletic fitness (9). Distance running (aerobic) and sprint work (anaerobic) should be included. It is crucial that young players undertake a strength training program designed for their age and ability before beginning a formal throwing program. These conditioning activities should be done in moderation, tinged with an element of fun, and in harmony with the guidance of parents, but not coerced.

Coaches of youth baseball should not only know the fundamentals of the game, but also teach the proper mechanics of pitching and throwing. Learning the correct technique as a youth can help prevent injuries throughout a player's career (10). Kinematic studies reveal that proper ball delivery varies little at different competition levels (11). There are significant differences, however, in shoulder and elbow kinetics at the higher levels of competition, even when scaled by height and weight (11). Changes in kinetics may increase the risk of injury as the pitcher progresses to higher competition levels (12).

Youth league regulations limit the innings pitched per week to reduce the risk of injury. Because pitch volume is important, it might be more appropriate for leagues to limit the number of pitches per outing, which could be enforced by the coaching staff (11). In the absence of league-imposed limits, parents should ensure that young players are not required to throw excessively. Physicians can educate parents about how much pitching and what kinds of pitches are safe for young players. (See "Pitching Safety for Kids: What to Tell Parents," below.)

The coaching staff, in important but less obvious preventive measures, should instill discipline, teamwork, sportsmanship, and the desire to "do your best" in young players. Above all, coaches should teach young people to have fun safely.

A Call for Adult Advocacy

Youth baseball is not an innocuous, injury-free sport. Pitchers, third basemen, and shortstops who throw hard subject their elbows to high valgus torques. Repetitive torque may considerably stress unfused physes, especially those centered on the medial humeral epiphysis, which produce clinical symptoms. Early symptoms may not be recognized as pathologic until osseous or ligamentous insults occur that require prolonged rehabilitation or surgical intervention. It behooves all who are involved in youth baseball—national committees, league personnel, parents, coaches, physicians, and researchers—to work together to learn more about the mechanism of injuries, prevention, and warning signs.

References

  1. Lyman SL, Fleisig GS, Osinski ED, et al: Incidence and determinants of arm injury in youth baseball pitchers: a pilot study, abstracted. Med Sci Sports Exerc 1998;30(5):S4
  2. Andrews JR, Schemmel SP, Whiteside JA, et al: Evaluation, treatment, and prevention of elbow injuries in throwing athletes, in Nicholas JA, Hershman EB (eds): The Upper Extremity in Sports Medicine, ed 2. St Louis, Mosby, 1995, pp 781-826
  3. König F: Lehrbuch der Allgemeine Chirgec fur Aerzten und Studinrede. Berlin, A Hirschwald, 1889, p 751
  4. Panner HJ: An affection of the capitulum humeri resembling Calvé-Perthes' disease of the hip. Acta Radiol 1927;8:617
  5. Brogdon BG, Crow NE: Little leaguer's elbow. Am J Roentgen 1960;83:671-675
  6. Slocum DB: Classification of elbow injuries from baseball pitching. Tex Med 1968;64(3):48-53
  7. Andrews JR, Arrigo CA, Chmielewski T, et al: Preventive and Rehabilitative Exercises for the Shoulder & Elbow. Birmingham, AL, American Sports Medicine Institute, 1997
  8. Axe MJ, Snyder-Mackler L, Konin JG, et al: Development of a distance-based interval throwing program for Little League-aged athletes. Am J Sports Med 1996;24(5):594-602
  9. Andrews JR, Arrigo CA, Chmielewski T, et al: Conditioning Program for Baseball Pitchers. Birmingham, AL, American Sports Medicine Institute, 1997
  10. Andrews JR, Fleisig GS: Preventing throwing injuries, editorial. J Orthop Sports Phys Ther 1998;27(3):181-188
  11. Fleisig GS, Barrentine S, Zheng N, et al: Baseball pitching biomechanics at various levels of development. Conference Proceedings, Twenty-First Annual Meeting of the American Society of Biomechanics, Clemson University, Clemson, SC, September 24-27, 1997, pp 30-31
  12. Fleisig GS, Barrentine S, Zheng N, et al: Kinematic and kinetic comparison of baseball pitching from a mound and throwing from flat ground. Conference Proceedings, Twentieth Annual Meeting of the American Society of Biomechanics, Georgia Tech, Atlanta, October 17-19, 1996, pp 153-154


Pitching Safety for Kids: What to Tell Parents

Sports medicine professionals can help prevent injuries in youth baseball by raising the awareness of coaches and parents about guidelines for safe participation. Physicians should be able to provide general answers to the following questions that parents commonly have:
  • How soon can my child begin pitching?
    Most children can safely begin to graduate from throwing to pitching at age 8.
  • How many pitches per day are safe?
    For an 8-year-old, a maximum of about 50 pitches per game followed by 2 days of rest (table A: not shown) is a good guideline. However, that number does not take into account hard throwing with friends or parents.
  • When can he or she learn to throw a curve ?
    Throwing a curveball increases the risk of injury because forceful supination and ulnar deviation places more medial stress on the forearm. Safe mechanics for throwing the curveball are difficult to master before the age of 13 or 14 (table A: not shown). Anecdotally, a more valuable pitch to learn early may be the change-up, which is thrown with essentially the same mechanics as a fastball.


Dr Whiteside is team physician and Eminent Scholar in Sports Medicine at Troy State University in Troy, Alabama. Dr Andrews is medical director of the American Sports Medicine Institute (ASMI), a clinical professor of orthopedic surgery at the University of Alabama at Birmingham (UAB), and an orthopedic surgeon at the Alabama Sports Medicine and Orthopaedic Center in Birmingham. Dr Fleisig holds the Smith & Nephew Chair of Research at ASMI and adjunct faculty positions at UAB and Troy State University. Drs Andrews and Fleisig are members of the USA Baseball Medical and Safety Advisory Committee. Dr Galloway is an associate professor at the Yale University School of Medicine, and Dr Goldberg is director of sports medicine at Yale University, New Haven. Address correspondence to James A. Whiteside, MD, Troy State University, Eldridge Hall, Troy, AL 36082; e-mail to [email protected].


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