Copyright 2002
Coaching Pitchers
By Michael G. Marshall, Ph.D.
Chapter Seven: Growth Plates of the Adolescent Elbow
From birth through early adolescence, epiphysial ossification centers sequentially
appear. In the mid-shaft of the pitching arm’s long bones, i. e., the humerus, radius and
ulna bones, diaphysial centers appear early in childhood. The proximal humerus has two
epiphysial centers and the distal humerus has four. The proximal and distal ends of the
ulna and radius bones have only one epiphysial center each.
a. Appearance Sequence
Critical pitching epiphysis remain non-united through adolescence. Consequently,
they are susceptible to irreversible injury. The following is a listing of the order in
which the critical baseball pitching epiphyses appear.
01.
02.
03.
04.
05.
06.
07.
08.
09.
10.
The humeral head epiphysis appears at two months.
The humeral capitulum epiphysis appears at six months.
The distal radial epiphysis appears at fourteen months.
The greater tuberosity epiphysis appears at fifteen months.
The radial head epiphysis appears at four years.
The medial epicondyle epiphysis appears at five years.
The distal ulnar epiphysis appears at six years.
The trochlear epiphysis appears at seven years.
The olecranon process epiphysis appears at eleven years.
The lateral epicondyle epiphysis appears at twelve years.
b. Union Sequence
The epiphysial centers of the humerus, ulna and radius also unite with their diaphysial
centers in a specific sequence. To determine the age at which pitching is safe, we need
to learn when these critical baseball pitching epiphysial and diaphysial centers unite.
01.
02.
03.
04.
05.
06.
07.
08.
09.
10.
The capitulum epiphysis unites at thirteen years.
The trochlear epiphysis unites at thirteen years.
The lateral epicondyle epiphysis unites at fourteen years.
The olecranon process epiphysis unites at fifteen years.
The medial epicondyle epiphysis unites at sixteen years.
The radial head epiphysis unites at sixteen years.
The distal ulnar epiphysis unites at nineteen years.
The greater tuberosity epiphysis unites at nineteen years.
The distal radial epiphysis unites at nineteen years.
The humeral head epiphysis unites at nineteen years.
This information shows that young baseball pitchers have incomplete critical skeletal
maturation until nineteen years old. However, the most critical growth plate with which
baseball pitchers need to have concern is the medial epicondyle. Five powerful baseball
pitching muscles arise from the medial epicondyle. They exert tremendous force during
all types of baseball pitches. Therefore, after the growth plate of the medial epicondyle
completely ossifies, the danger of irreparable damage to the baseball pitching arm
significantly decreases. Nevertheless, baseball pitching coaches must always be alert to
complaints of discomfort located deep in the bone at the distal ulnar epiphysis, the greater
tuberosity epiphysis of the humerus, the distal radial epiphysis and the humeral head
epiphysis in pitchers up to twenty years of age.
…
Table 9.1: Percent of Three Types of Pitching Elbow Injuries
|--------------------------------------------|
|
| Non-Baseball
Baseball
|
Baseball
|
| Pitchers
| Non-Pitchers
|
Players
|
|--------------------------------------------------------------------------------------|
| Premature Medial Epicondyle Growth
|
|
|
|
| Plate Closure and Separation
|
95.0%
|
48.8%
|
7.5%
|
|--------------------------------------------------------------------------------------|
| Medial Epicondyle Fragmentation
|
15.0%
|
12.8%
|
0.0%
|
|--------------------------------------------------------------------------------------|
| Capitular/Radial Head Osteochondritis |
08.6%
|
05.7%
|
0.0%
|
|--------------------------------------------------------------------------------------|
1. Medial Epicondyle Injuries
Dr. Adams provided X-rays and case histories of five 12 and 13 year old pitchers with
medial epicondyle injuries.
a) Slight Separation
Case 1: A 12 year old pitcher with one year of pitching experience complained of
elbow soreness. Dr. Adams found that the growth plate in his pitching elbow’s medial
epicondyle had prematurely closed and his humeral growth plate had slightly separated.
The arrow points to the medial epicondyle of the pitching elbow. The muscles that
attach to the medial epicondyle exerted greater traction stresses than the growth plate
could withstand. Consequently, the medial epicondyle growth plate separated from its
humeral connection.
The medial epicondyle growth plate shows very clearly open. The capitular growth
plate shows very clearly open. The radial head growth plate shows very clearly open.
The lateral epicondyle ossification center has not yet appeared. This X-ray indicates an
11 year old male. Therefore, this 12 year old pitcher was a one year delayed maturer.
b) Increased Bone Density
Case 2: A 13 year old pitcher with two years of pitching experience admitted that he
kept his elbow pain secret. However, during Pony League try-outs, sufficient swelling
and tenderness developed over his medial epicondyle that he had to seek medical
advice. (Pony League baseball includes 13-15 year olds.) Dr. Adams found that the
medial epicondyle growth plate of his pitching arm had prematurely closed and showed
increased bone density.
c) Dissecans Fragmentation
Case 3: A 13 year old pitcher with four years of pitching experience acknowledged
previous elbow soreness. However, during Pony League try-outs, he experienced severe
elbow pain. Physical examination located soreness over the medial epicondyle. Dr.
Adams found that the medial epicondyle growth plate of his pitching arm had
prematurely closed and showed dissecans fragmentation (Cartilage incompletely
separates from underlying bone).
The arrow points to the medial epicondyle growth plate. The muscles that attach to
the medial epicondyle exerted greater traction stress than the growth plate could
withstand. As a consequently, the medial epicondyle growth plate completely tore away
from its humeral connection.
The medial epicondyle growth plate appears mature size and its growth plate only
shows faintly open. The capitular growth plate has almost disappeared. The radial head
growth plate shows open. The lateral epicondyle growth plate appears mature size with
a slight opening at proximal end of the growth plate. This X-ray indicates a 13 year
old. Therefore, this 13 year old pitcher had equated maturation.
d) Avulsion Fragmentation
Case 4: A 12 year old pitcher with two years of pitching experience complained of
elbow pain. Dr. Adams found that medial epicondyle growth plate of his pitching arm
had prematurely closed and showed avulsion fragmentation (Cartilage completely tears
away from the underlying bone).
e) Complete Transverse Fracture
Case 5: During a Pony League game, a 13 year old pitcher with four years of
pitching experience felt his elbow snap. Dr. Adams found that the medial epicondyle
growth plate of his pitching arm had prematurely closed and showed a complete
transverse fracture.
The arrow points to the medial epicondyle growth plate. The muscles that attach to
the medial epicondyle exerted greater traction stresses than the growth plate could
withstand. Consequently, the medial epicondyle fractured.
The capitular growth plate has almost disappeared. The radial head growth plate
shows open. The lateral epicondyle growth plate appears mature size with some opening
at its proximal end. This X-ray indicates a 13 year old. Therefore, this 13 year old
pitcher has equated maturation.
f) Ulnar Nerve Pathway
Irreparable medial epicondyle injuries devastate adolescent pitchers. However,
medial epicondyle growth and development deformations cause another devastating
injury. The posterior aspect of the medial epicondyle forms the canal through which the
ulnar nerve travels. The ulnar nerve sensitizes the skin of the little finger and the lateral
one-half of the ring finger and innervates intrinsic hand muscles. When bumped, the
ulnar nerve sends tingling sensations down the forearm to the little finger. People call
this ulnar nerve location, their ‘crazy bone’.
Medial epicondyle separations, fractures or avulsions alter the ulnar nerve canal.
Consequently, irregularly formed ulnar canals aggravate ulnar nerves.
2. Capitulum and Radial Head Injuries
Dr. Adams also provided X-rays and case histories of six pitchers with osteochondritis
(cartilage inflammation) on the articulating surface between the capitulum and radial
head During pitching arm decelerations, the weight of pitchers’ forearms, wrists, hands
and fingers pulls the radius bone away from their humerus bone. Then, during pitching
arm recovery, their radial heads elastically slam back against their humeral capitular
surface. Therefore, the growth plates of the radial head and the capitulum are ‘rebound
collision’ growth plates.
a) Capitulum Lesion
Case 1: During physical examination, a 9 year old male with one year of pitching
experience denied that he felt any elbow pain during or after pitching. Nevertheless, Dr.
Adams found that the articular surface of his capitular growth plate had a lesion
(pathological tissue change).
b) Capitulum Osteochondritis
Case 2: A 13 year old pitcher with five years of pitching experience suffered elbow
pain during Pony League games, but he waited until after the season to seek medical
attention for pronounced tenderness over his radio-humeral joint. Dr. Adams found that
the capitular growth plate of his humerus had prematurely closed and showed a large
osteochondritis area.
c) Cartilage Erosion and Radial Head Enlargement
Case 3: A 13 year old pitcher with four years of pitching experience stopped
pitching. Three years later, he suffered from severe pain and an inability to completely
straighten his pitching elbow. He had pronounced soreness over the radio-humeral
joint. Dr. Adams found that the medial epicondyle growth plate of his pitching arm had
prematurely closed, the capitular growth plate showed cartilage erosion, his radial head
had enlarged and his elbow had lost thirty degree of its elbow extension range of motion.
d) Permanent Radial Head Deformation
Case 4: A 12 year old with three years of pitching experience suffered from severe
elbow pain during playoffs. Dr. Adams recommended that he stop pitching until the
growth plates in his pitching arm closed. However, his parents, coaches and he
disregarded the advice and, during Pony League try-outs, his elbow pain increased. Xrays determined that his pitching elbow had radial head osteochondritis. After two years
of complete rest, additional X-rays showed his radial head had permanently deformed.
e) Deformation, Cartilage Erosion and Loose Fragments
Case 5: An adolescent pitcher with three years of pitching experience stopped
pitching when he could no longer completely straighten his pitching elbow. He had
pronounced tenderness over his radio-humeral joint. Dr. Adams found that the radial
head growth plate of his pitching arm had prematurely closed, his humeral capitulum
showed a large area of cartilage erosion and his humeral capitulum showed loose
articular cartilage fragments. Dr. Adams exfoliated (stripped layers away) the eroded
capitular articular surface cartilage and removed several loose cartilage fragments.
However, his parents would not permit Dr. Adams to remove the deformed radial head.
f) Radial Head Removal
Case 6: Severe elbow pain forced a 15 year old pitcher with three years of pitching
experience to stop pitching. When his elbow became quite painful and he could no
longer completely straighten it, he sought medical attention. Dr. Adams found that his
radial head growth plate had deformed and his humeral capitular growth plate showed an
osteochondritic lesion. The patient refused corrective surgery. However, at 19 years
old, he returned with elbow ‘locking’. Dr. Adams found that his loose cartilage
fragments had calcified such that Dr. Adams had to remove the calcified fragments and
his the entire head of his radius bone. Finally, the patient had no elbow pain and, in nonstrenuous activities, he regained functional use of this elbow.
c. Little League shoulder-osteochondritis of the proximal humeral epiphyses of
boy baseball pitchers
In the 1966 California Medicine Journal, Orthopedic Surgeon Joel E. Adams M.D.,
reported on five 13-15 year old pitchers with shoulder pain.
The growth plate of the humeral head unites with the growth plate of the greater
tuberosity several years before the combined growth plate of the humeral head and
greater tuberosity unites with the proximal humeral shaft. The supraspinatus,
infraspinatus and teres minor muscles attach to the humeral greater tuberosity.
Therefore, during baseball pitching deceleration, the greater tuberosity growth plate is a
‘traction’ epiphysis.
1. Greater Tuberosity Growth Plate Injuries
a) Premature Closure
Case 1: A 13 year old pitcher with one year of pitching experience and considerable
home practice experienced severe shoulder pain when he tried out for Pony League.
After three months of complete rest, he started pitching again and again felt discomfort
when he threw hard. Dr. Adams found that the combined humeral head and greater
tuberosity growth plate had prematurely closed. Dr. Adams advised waiting until the
growth plates of his pitching arm completely closed before he resumed pitching.
b) Demineralization and Separation
Case 2: A 15 year old pitcher with six years of pitching experience suffered from
increasing shoulder pain that forced him to stop pitching and seek medical attention. Dr.
Adams found that the combined humeral head and greater tuberosity growth plate had
demineralized and had slightly widened. Dr. Adams advised waiting until the growth
plates of his pitching arm completely closes before he resumed pitching.
c) Separation and Demineralization
Case 3: A 13 year old pitcher with one year of pitching experience suffered severe
shoulder pain after trying out for Pony League and sought medical attention. While Dr.
Adams examination found pain-free complete range of movement in his pitching
shoulder, to firm digital pressure and some pitching arm pull pain, the young man
complained of slight tenderness in proximal humerus. Dr. Adams found that the
combined humeral head and greater tuberosity growth plate had severely demineralized
and widened. Dr. Adams advised waiting until the growth plates of his pitching arm
completely closes before he resumed pitching.
d) Separation and Fragmentation
Case 4: A 14 year old pitcher with five years of pitching experience suffered
gradually increasing shoulder pain. Dr. Adams found that the combined head and
greater tuberosity growth plate had widened and fragmented. Several months of
complete rest reduced the shoulder pain and his X-rays returned to normal. Dr. Adams
advised waiting until the growth plates of his pitching arm completely closes before he
resumed pitching.
e) Separation, Deformation and Demineralization and Scapular Spur
Case 5: A 15 year old pitcher with five years of pitching experience suffered
gradually increasing pain in the back of his shoulder during the deceleration phase of the
pitching motion. Finally, he stopped throwing and sought medical attention. When Dr.
Adams applied firm digital pressure, the young man complained of proximal humeral and
postero-inferior glenoid pain. Dr. Adams found that the combined humeral head and
greater tuberosity growth plate had widened, deformed and demineralized and his glenoid
fossa’s postero-inferior margin showed an abnormal bony growth. (The triceps brachii’s
long head arises from the glenoid fossa’s postero-inferior margin.) Complete rest
reduced his pain. Dr. Adams advised that this young man never pitch again.
Complete rest usually remedies shoulder pain. Consequently, pitchers do not seek
medical attention. Therefore, the medical literature does not accurately reflect shoulder
growth plate injuries.
d. Additional References
For many years, researchers have studied the effects of pitching on adolescent pitching
arms. Unfortunately, few parents know of this research. Therefore, I am including a list
of research articles that parents should locate, copy and read. Parents must determine for
themselves whether and/or how much they want their adolescent pitchers to pitch. I
stopped collecting these articles several years ago. Therefore, to have your libraries upto-date, parents will have to search through the research periodicals that I cite for more
recent information.
01. Wilmoth, C. L. Recurrent fractures of humerus due to sudden extreme muscular
action J BONE JOINT SURG 12:168-169 1930.
02. Shands Jr., A. R. The regeneration of hyaline cartilage in joints ARCH SURG
22:137-178 1931.
03. Brewster, A. H. and M. Farp Fractures in the region of the elbow in children SURG
GYN OBST 71:643-649 1940.
04. Bennett, G. E. Shoulder and elbow lesions of professional baseball pitchers JAMA
117:510-514 1941.
05. Bennett, G. E. Shoulder and elbow lesion disturbances of baseball players ANN
SURG 126:107-110 1947.
06. Smith, F. M. Medial epicondyle injuries JAMA 142:396-402 1950.
07. Cox, F. J. and M. T. Hurley Fractures about the elbow in children CAL MED
76(1):13-15 1952.
08. Herzmark, M. H. and F. R. Klune Ball-throwing fractures of the humerus MED
ANN D.C. 21:196-199 1952.
09. Dotter, W. E. Little leaguer's shoulder fracture of the proximal epiphysial cartilage
due to baseball pitching GUTHRIE CLIN BULL 23:68-72 1953.
10. Goff, C. N. Legg-Perthes disease and related osteochondritis of youth CHARLES
C. THOMAS Springfield, IL 1954.
11. Norell, H. G. Roentgenologic visualization of the extracapsular fat-its importance
in the diagnosis of traumatic injuries to the elbow ACTA RADIOL 42:205-210 1954.
12. Harsha, W. N. Effects of trauma upon epiphyses CLIN ORTHO 10:140-147 1957.
13. Nagura, S. The so-called osteochondritis dissecans of Koneg CLIN ORTHO
18:110-119 1957.
14. Bennett, G. E. Elbow and shoulder lesions of baseball players AM J SURG 98:484492 1959.
15. Bingham, E. L. Fractures of the humerus from muscular violence US ARMED
FORCES MED J 10:22-25 1959.
16. Slocum, D. B. Mechanics of common shoulder injuries AM J SURG 98:395 1959.
17. Brodgen, B. G. and N. E. Crow Little league elbow AM J ROENT 83:671-674 1960.
18. Hale C. J. Injuries among 771,810 Little League baseball players J SPORTS MED
PHYS FITNESS 1:80-83 1961.
19. Middleman, J. C. Shoulder and elbow lesions of baseball players AM J SURG
102:627-632 1961.
20. Bateman, J. E. Athletic injuries about the shoulder in throwing and body contact
sports CLIN ORTHO 23:75-83 1962.
21. Salter, R. B. and R. W. Harris Injuries involving the epiphysial plate J BONE
JOINT SURG 45A:587-622 1963.
22. Trias, A. and R. D. Ray Juvenile osteochondritis of the radial head J BONE JOINT
SURG 45A:576-582 1963.
23. Adams, J. E. Injury to the throwing arm-a study of traumatic changes in the elbow
joints of boy baseball players CAL MED 102(2):127-132 1965.
24. Adams, J. E. Little league shoulder-osteochondritis of the proximal humeral
epiphyses of boy baseball pitchers CAL MED 105(1):22-25 1966.
25. Larsen, R. L. and R. O. McMahan The epiphyses and the childhood athlete JAMA
196:607-612 1966.
26. Morris, J. M. and W. B. Blickenstaff Fatigue fractures-a clinical study CHARLES
C. THOMAS Springfield, IL 1967.
27. Adams, J. E. Bone injuries in very young athletes CLIN ORTHO REL RES
58:129-140 1968.
28. Slocum, D. B. Classification of elbow injuries from baseball pitching TEX MED
64:48-53 1968.
29. King, J. W., Brelsford, H. J. and H. S. Tullos Analysis of the pitching arm CLIN
ORTHO 67:116-123 1969.
30. Godshall, R. W. and C. A. Hansen Traumatic ulnar neuropathy in adolescent
baseball pitchers J BONE JOINT SURG 53:359 1971.
31. Ellman, H. Osteochondritis of the radial head J BONE JOINT SURG 54A:1560
1972.
32. Torg, J. S., H. Pollack and P. Sweterlitsch The effect of competitive pitching on the
shoulders and elbows of pre-adolescent baseball players PEDIATRICS 49:267-272 1972.
33. Tullos, H. S. and J. W. King Lesions of the pitching arm in adolescents JAMA
220:264 1972.
34. Torg, J. S. Little league-the theft of a carefree youth PHYS SPORTSMED 1:72-78
1973.
35. Brown, R. et al Osteochondritis of the capitulum J SPORTS MED 2:27-46 1974.
36. Lipscomb, A. B. Baseball pitching injuries in growing athletes J SPORTS MED
3(1):25-34 1975.
37. Francis, R. T., T. Bunch and B. Chandler Little league elbow-a decade later PHYS
SPORTSMED 4:88-94 1976.
38. Larsen, R. L. et al. Little league survey-the Eugene study AM J SPORTS MED
4:201-209 1976.
39. Gugenheim Jr., J. J., R. F. Stanley and G. W. Woods Little league survey-the
Houston study AM J SPORTS MED 4:189-200 1976.
40. Slager, R. F. From little league to big league-the weak spot is the arm AM J
SPORTS MED 5(2):37-48 1977.
41. Torg, J. S. and R. A. Moyer Non-union of a stress fracture through the olecranon
epiphysial plate observed in an adolescent baseball pitcher J BONE JOINT SURG
59(A):264-265 1977.