The posterior cuff muscles provide dynamic posterior gleno-humeral stability, with the supraspina-tus functioning as a powerful abduc-tor of the arm in the scapular plane and the infrasp
Trang 1Skeletally Immature Athlete
Frank S Chen, MD, Veronica A Diaz, MD, Mark Loebenberg, MD, and Jeffrey E Rosen, MD
Abstract
Shoulder and elbow injuries in the
skel-etally immature are becoming more
frequent as more children and
ado-lescents participate in recreational and
competitive athletics requiring
repet-itive overhead motion Although most
of these injuries result from chronic
overuse, traumatic injuries to the
shoul-der and elbow also occur The injury
patterns in these patients are distinct
because their developing physes are
relatively weak Whereas injuries in
adults tend to involve ligamentous and
soft-tissue structures, injuries in the
skeletally immature commonly involve
the physes as well
Shoulder and Elbow
Anatomy
To manage these injuries effectively,
clinicians should understand
func-tional shoulder and elbow anatomy
in children and adolescents, as well
as the normal developmental
se-quence of the primary and secondary ossification centers, which represent potential sites of injury
Shoulder
The proximal humeral physis, which has formidable growth and re-modeling potential,1,2contributes ap-proximately 80% of the longitudinal growth of the upper extremity It is composed of three primary ossifica-tion centers—the humeral head, the greater tuberosity, and the lesser tu-berosity—that coalesce between the ages of 5 and 7 years to form a sin-gle proximal humeral epiphysis Sub-sequently, the proximal humeral phy-sis fuses approximately between the ages of 14 and 17 years in females and
16 and 18 years in males.1,3
The capsuloligamentous and mus-cular structures of the shoulder pro-vide static and dynamic stability of the glenohumeral joint.4-6The static stabilizers function primarily at the extremes of the range of motion
(ROM) as they reciprocally tighten and loosen to limit humeral head translation The dynamic stabilizers provide stability during the midrange
of motion, when the static stabilizers are lax The dynamic stabilizers con-tract in a coordinated pattern to pro-vide concavity-compression of the humeral head within the glenoid cav-ity, limiting abnormal translation.4-6
Different portions of the joint cap-sule, glenohumeral ligaments, and gle-noid labrum provide static gleno-humeral stability, depending on the position of the arm.4,6The anterosu-perior capsule, coupled with the struc-tures of the rotator interval, limit in-ferior and posterior translation of the
Dr Chen is Attending Physician, Sports Medi-cine Department, Palo Alto Medical Foundation, Palo Alto, CA Dr Diaz is Resident, University
of Miami/Jackson Memorial Hospital, Miami, FL.
Dr Loebenberg is Consultant Surgeon, Assaf Harofeh Medical Center, Tel Aviv University School of Medicine, Tzrifin, Israel Dr Rosen is Assistant Professor, Orthopaedic Surgery, and Di-rector, Child & Adolescent Sports Medicine, Sports Medicine/Arthroscopic Surgery, NYU–Hospital for Joint Diseases, New York, NY.
None of the following authors or the departments with which they are affiliated has received anything
of value from or owns stock in a commercial com-pany or institution related directly or indirectly
to the subject of this article: Dr Chen, Dr Diaz,
Dr Loebenberg, and Dr Rosen.
Reprint requests: Dr Rosen, NYU–Hospital for Joint Diseases, Suite 2, 305 Second Avenue, New York, NY 10003.
Copyright 2005 by the American Academy of Orthopaedic Surgeons.
The intensity of training and competition among young athletes can place them at
increased risk of acute and chronic injuries, which occur in patterns unique to the
skeletally immature athlete Prompt recognition and treatment of these injuries are
critical to prevent long-term functional disability and deformity Children and
ad-olescents participating in recreational and organized sports are particularly
suscep-tible to a broad spectrum of shoulder and elbow injuries involving both osseous and
soft-tissue structures Understanding the relevant functional anatomy,
biomechan-ics of throwing, and pathophysiology of injury can help the clinician manage
com-mon acute traumatic injuries, some of which may result in chronic problems
Over-use injuries occur more frequently than do acute, traumatic injuries, and early
recognition, coupled with appropriate treatment or prevention, can help restore and
maintain normal shoulder and elbow function.
J Am Acad Orthop Surg 2005;13:172-185
Trang 2humeral head in the adducted arm.4,7
The middle glenohumeral ligament
functions to limit anteroposterior (AP)
translation in the abducted arm at the
midrange of external rotation The
in-ferior glenohumeral ligament, a
com-plex structure possessing anterior and
posterior bands with an interposing
axillary pouch, serves as the
prima-ry restraint to AP as well as to
infe-rior translation in the abducted and
maximally externally rotated arm.4,7
The posterior capsule, which does not
have any direct posterior ligamentous
reinforcements, is important in
lim-iting posterior humeral translation in
the adducted, internally rotated, and
forward-flexed arm.4,5Overall static
stability is further enhanced by the
la-brum, which deepens the concavity
of the glenoid socket in both the AP
and superior-inferior dimensions The
labrum also acts as an anchor point
for the capsuloligamentous structures
and the long head of the biceps
ten-don Labral injury or detachment is
commonly associated with injury to
the associated capsuloligamentous
structures.4-6
The dynamic stabilizers are the
ro-tator cuff, the long head of the biceps,
the deltoid, and the scapulothoracic
muscles The posterior cuff muscles
provide dynamic posterior
gleno-humeral stability, with the
supraspina-tus functioning as a powerful
abduc-tor of the arm in the scapular plane
and the infraspinatus and teres
mi-nor combining to externally rotate and
flex the humerus.5,6,8 The
subscapu-laris, in addition to functioning as an
internal rotator of the humerus, is an
important dynamic anterior
stabiliz-er, given its confluence with the
an-terior capsule.5,6,8The long head of the
biceps is important in preventing
an-terior and superior humeral head
translation.9Finally, the deltoid and
scapulothoracic muscles—including
the trapezius, levator scapulae,
ser-ratus anterior, and both rhomboid
muscles—function to position the
scapula to provide maximum
stabil-ity at the glenohumeral articulation.4-6
Elbow
Skeletal maturation of the elbow occurs at primary and secondary os-sification centers within the distal hu-merus, radius, and ulna Six second-ary ossification centers represent potential sites of injury (1) The capi-tellum has a variable ossification pat-tern but usually appears by age 2 years in males (2) Ossification of the radial head occurs next, between age
4 and 5 years, followed by (3) the me-dial epicondyle between age 6 and 7 years and (4) the trochlea between age
9 and 10 years (5) The olecranon ap-pears next, usually by age 11, fol-lowed by (6) the lateral epicondyle during adolescence.10,11Ossification rates are highly variable and also dif-fer by sex; rates in females usually precede those of males by 6 to 12 months Therefore, clinicians should obtain radiographs of the contralat-eral side to evaluate elbow injuries in the skeletally immature patient
The osseous anatomy of the el-bow allows flexion-extension and pronation-supination through the ulnohumeral and proximal radioul-nar articulations, respectively In full extension, the elbow possesses a normal valgus-carrying angle of 11°
to 16° This bony configuration pro-vides approximately 50% of the overall stability of the elbow, primar-ily against varus stress in the ex-tended elbow The anterior joint cap-sule, the ulnar collateral ligament (UCL) complex, and the lateral col-lateral ligament complex provide the remainder of elbow stability.12,13
The UCL complex consists of three main portions: the anterior bundle, posterior bundle, and oblique bundle (transverse ligament) The anterior bundle is functionally the most im-portant in providing stability against valgus stress and is further
subdivid-ed into distinct anterior and
posteri-or bands, possessing reciprocal functions.12-14The anterior band is the primary restraint to valgus stress at lesser degrees of flexion and is more susceptible to injury in the extended
elbow.13,14The posterior band, because
of its primary stabilizing role at
high-er degrees of elbow flexion, is func-tionally more important than the an-terior band in the overhead throwing athlete
Originating from the medial epi-condyle, the flexor-pronator muscu-lature provides dynamic valgus sta-bility of the elbow.15From proximal
to distal, this muscle mass includes the pronator teres, flexor carpi radi-alis, palmaris longus, flexor digi-torum superficialis, and flexor carpi ulnaris Electromyographic (EMG) and biomechanical studies have shown the pronator teres, flexor dig-itorum superficialis, and flexor carpi ulnaris muscles, which form muscu-lotendinous units overlying the UCL complex, to be primarily responsible for maintaining dynamic valgus sta-bility.13,15
The lateral collateral ligament com-plex is less well understood than the medial ligamentous structures It is composed of three distinct portions: the radial collateral ligament, the lat-eral UCL, and the accessory latlat-eral col-lateral ligament.12,14The lateral UCL has been shown to be the primary re-straint against rotatory subluxation of the ulnohumeral joint; injury to this structure allows posterolateral rota-tory instability to develop.14The ra-dial collateral ligament is reportedly
an important secondary restraint of the lateral elbow, along with the ex-tensor muscles, including the exten-sor digitorum communis, brachiora-dialis, and extensor carpi radialis longus and brevis.12,14These muscles impart dynamic stability to the
later-al elbow EMG studies have shown that they exhibit complex, interdepen-dent firing patterns throughout the throwing motion; thus, they may be vulnerable to overuse injuries.8,15
Biomechanics of Throwing
The overall motion and kinematics of throwing in adolescents are similar to
Trang 3those in adults, with stresses that are
similar but of lesser absolute
magni-tude.16 Proper throwing mechanics
can and should be taught at a young
age, along with strengthening of the
upper extremity, to reduce injury
rates
Although specific techniques of
overhead throwing vary with
differ-ent sports, the basic motion is
simi-lar The baseball pitch has been the
most studied and can be divided into
five main stages8,17(Fig 1) In stage
1, or windup, the elbow is flexed and
the shoulder is in slight internal
ro-tation; muscular activity is minimal
Stage 2, or early cocking, begins
when the ball leaves the
nondomi-nant gloved hand and ends when the
forward foot contacts the ground The
shoulder begins to abduct and rotate
externally This stage entails early
activation of the deltoid followed by
activation of the supraspinatus,
in-fraspinatus, and teres minor
mus-cles.5,6,8,17
Stage 3, or late cocking, is
charac-terized by further shoulder abduction
and maximal external rotation as well
as increasing elbow flexion and
fore-arm pronation Activity levels of the
supraspinatus, infraspinatus, and
te-res minor reach their peak during the
midportion of this phase, and
sub-scapularis and periscapular
muscu-lar activity increase.6,8,17Tremendous
shear forces are generated across the
anterior shoulder, predominantly by
the rotator cuff muscles.16,17The long
head of the biceps and the
subscap-ularis also contribute to dynamic
an-terior shoulder stability during late
cocking.8,9
In stage 4, or acceleration, the
shoulder musculature generates a
large forward force on the extremity,
resulting in internal rotation and
ad-duction of the humerus coupled with
rapid elbow extension.5,6,17,18Working
in concert with the periscapular
mus-cles, the subscapularis exhibits high
activity during this stage.5,6,17,18Stage
4 ends with ball release as
tremen-dous valgus stresses are generated
about the medial elbow struc-tures.13,18The anterior bundle of the UCL bears most of these forces Sec-ondary supporting structures, such as the flexor-pronator musculature, fa-cilitate transmission of these signif-icant stresses Most elbow injuries oc-cur during this stage because these forces are concentrated on the
medi-al elbow structures Bmedi-all release medi-also generates tremendous compression and rotatory stresses laterally in the radiocapitellar articulation, and pow-erful triceps contraction imparts ten-sile forces in the posterior compart-ment.13,19
In stage 5, or follow-through, all excess kinetic energy is dissipated as the upper extremity decelerates rap-idly The stage ends when all motion
is complete Forceful deceleration of the upper extremity occurs as the el-bow reaches full extension and the shoulder is maximally internally ro-tated.8,13The biceps and brachialis ex-hibit high activity levels during this phase, as does the posterior cuff mus-culature, which contracts
eccentrical-ly to stabilize the glenohumeral joint.8,9The deltoid, latissimus dorsi, and subscapularis muscles contribute
to shoulder stability and prevent
hu-meral head subluxation Tremendous torque is generated across the gleno-humeral joint as the arm rapidly de-celerates.5,18
Acute Injuries of the Shoulder and Elbow
Traumatic osseous and soft-tissue in-juries of the shoulder and elbow in the skeletally immature athlete span
a wide range of injury patterns, some
of which may lead to chronic insta-bility The most commonly observed acute injury patterns in this popula-tion are glenohumeral dislocapopula-tions and acute medial epicondylar fractures
Traumatic Glenohumeral Dislocations
Although relatively uncommon, traumatic shoulder dislocations do oc-cur, primarily during collision sports The incidence is as high as 7% in young athletes participating in ice hockey.20In addition, up to 40% of all primary shoulder dislocations occur
in patients younger than 22 years.20
AP, axillary, and lateral views of the shoulder always should be obtained because associated fractures of the
gle-Figure 1 Phases of the throwing motion in baseball (Adapted with permission from DiGiovine NM, Jobe FW, Pink M, Perry J: An electromyographic analysis of the upper
ex-tremity in pitching J Shoulder Elbow Surg 1992;1:15-25.)
Trang 4noid rim or Hill-Sachs lesions may
oc-cur Magnetic resonance imaging
(MRI), MR arthrography, or
comput-ed tomography arthrography may
demonstrate a Bankart lesion or
la-bral detachment (Fig 2) Intra-articular
contrast medium can be used to
out-line and properly visualize the labrum;
without contrast medium, these
struc-tures cannot be fully evaluated
La-bral injury or detachment usually
de-notes concomitant injury of the
associated capsuloligamentous
struc-tures, which can result in distinct
in-stability patterns, depending on the
region of capsulolabral injury.4-6,17
Recurrent instability after a
trau-matic injury in the skeletally
imma-ture patient is common; rates range
from 25% to 90% in adolescents and
up to 100% in patients with open
phy-ses.21,22Surgical intervention may be
indicated when symptoms of
insta-bility persist despite 4 to 6 months of
nonsurgical management—a brief
pe-riod of immobilization followed by
dy-namic shoulder stabilization with
del-toid, rotator cuff, and scapular muscle
strengthening Because recurrence
rates are high in this population and
because arthroscopic stabilization
tech-niques have advanced, early
stabili-zation increasingly is being
recom-mended for athletes with traumatic
instability with labral detachments or
bony Bankart lesions
Arthroscopic techniques now
ap-pear to produce functional results
comparable to those of open Bankart
or anterior capsulolabral
reconstruc-tion procedures.23-29Arthroscopy has
the potential advantages of better
vi-sualization of the capsulolabral
com-plex and other intra-articular
struc-tures, less surgical dissection (which
decreases scarring), less damage to
surrounding tissues (which
decreas-es morbidity), and earlier and more
rapid rehabilitation with improved
ROM, especially in external
rota-tion.25,26,29Arthroscopic suture anchors
can be used for labral repair, and
cap-sular pathology can be addressed
con-comitantly with suture
capsulorrha-phy to maximize functional outcome and minimize the risk of recurrence (Fig 3)
Postoperative shoulder immobili-zation is generally maintained for the first 10 to 14 days, followed by a gressive ROM and strengthening pro-gram In patients with anterior insta-bility, shoulder abduction and external rotation in the 90°–90° position over-head should be avoided in the early postoperative period Therapy is di-rected at strengthening the rotator cuff, deltoid, and scapulothoracic muscles
to provide dynamic stabilization of the shoulder These techniques and pro-tocols can achieve results compara-ble to those of traditional open sta-bilization techniques, so that the patient may be allowed to return to athletic activity at 3 to 6 months.23-29
Medial Epicondylar Fractures
Avulsion fractures of the medial epicondyle result from extreme val-gus loads or violent muscle contrac-tions during the throwing motion and commonly occur in adolescents as the medial epicondyle begins to fuse.11,21
Patients may report feeling a “pop”
or “giving way” of the elbow, followed
by acute pain; they also may describe locking or catching of the elbow Ex-amination reveals tenderness and swelling over the medial epicondyle with decreased ROM and valgus in-stability.11Plain radiography shows avulsion of the medial epicondylar apophysis with varying degrees of dis-placement, depending on the force of the trauma.10,11Type 1 fractures (a large fragment that may involve the entire epicondyle) occur in younger children, and type 2 fractures (small fragments)
in adolescents older than 15 years of age with fused physes.10,11
Treatment is guided by the extent
of fracture displacement Minimally displaced fractures are treated with immobilization for 2 to 3 weeks, fol-lowed by a rehabilitation protocol, in-cluding protected active and active-assisted ROM exercises.10,11Nonunions have been reported as a result of
in-adequate immobilization and activ-ity modification because repetitive traction from resumed throwing leads
to residual motion and stress at the fracture site, inhibiting physeal fusion Late surgical excision may be
indicat-ed for pain For patients with fractures displaced >5 mm, valgus stability should be tested clinically and, if nec-essary, should include valgus stress radiography A medial joint line open-ing >2 to 3 mm is considered abnor-mal In the presence of instability or marked rotation or displacement of the medial epicondyle fragment, sur-gical reattachment by open reduction and internal fixation (with smooth Kir-schner wires) is indicated to restore valgus stability Anatomic reduction may prevent late sequelae, such as radiocapitellar degenerative
chang-es.10,11,21
Chronic Overuse Injuries
Although skeletally immature ath-letes sustain a variety of acute shoul-der and elbow injuries, most of these are chronic overuse injuries
second-Figure 2 Anterior labral detachment Axial T2-weighted MRI scan demonstrating avul-sion of the anterior labrum (curved arrow) and the fluid between the glenoid (G) and the displaced labrum S = subscapularis tendon (Reproduced with permission from Kingston S: Diagnostic imaging of the upper
extrem-ity, in Jobe FW [ed]: Operative Techniques in
Up-per Extremity Sports Injuries St Louis, MO:
Mosby, 1996, p 46.)
Trang 5ary to cumulative stresses from
repet-itive overhead throwing motion
Chronic injuries occur
predominant-ly in baseball players, but participants
in other sports involving similar
over-head activity, such as football, tennis,
swimming, or volleyball, also are
sus-ceptible These injuries occur in
spe-cific patterns depending on the nature
of the repetitive stresses and the
de-velopmental anatomy of the athlete
Injuries of the Shoulder
Shoulder and elbow injuries increase
in frequency during the mid to late
teenage years As the athlete matures
and gains strength, the shoulder is
subjected to greater stresses during
the throwing motion The most
com-mon overuse injuries include Little
League shoulder, rotator cuff
tendini-tis, and glenohumeral instability—
anterior, posterior, and
multidirec-tional
Little League Shoulder
Little League shoulder is
epiphysi-olysis of the proximal humerus
sec-ondary to repetitive microtrauma from
overhead activity Patients present
with diffuse shoulder pain that is
worse with throwing Arecent increase
in the throwing regimen often pre-cedes the onset of symptoms.21,30,31
Findings include tenderness and swelling over the anterolateral shoul-der, with weakness on resisted abduc-tion and internal rotaabduc-tion External ro-tation contractures with decreased internal rotation also may develop Ra-diographs usually reveal proximal physeal widening, best appreciated on
an AP view taken with the shoulder
in external rotation Depending on the severity of the condition, radiographs also may demonstrate metaphyseal demineralization and fragmentation coupled with physeal irregularity and periosteal reaction.21,30,31
Treatment involves an initial period
of 2 to 3 months of rest and activity modification, followed by a progres-sive throwing program The protocol calls for a light tossing schedule and gradually progresses with increasing distance and velocity This protocol has shown excellent results, with up
to 91% of patients remaining asymp-tomatic.21Because of the great remod-eling potential of the proximal hu-merus, long-term consequences are rare However, problems can occur and may include premature physeal clo-sure with resultant humeral length
dis-crepancy or angular deformity, as well
as subsequent Salter-Harris fractures
of the proximal humeral epiphysis Factors that contribute to the de-velopment of Little League shoulder include excessive throwing, poor technique, and muscle-tendon imbal-ance Coaches, trainers, and parents should be aware of the American Academy of Orthopaedic Surgeons (AAOS) guidelines for pitching (Ta-ble 1) Developing proper throwing mechanics and limiting the number
of pitches and innings thrown are cru-cial for preventing Little League shoulder Control, not speed, should
be emphasized in training regimens
In addition, educating coaches and players about appropriate stretching, strengthening, and conditioning and proper throwing mechanics is vital
Rotator Cuff Tendinitis and Impingement
Adolescent overhead athletes— especially those involved in baseball, swimming, and tennis—often sustain tendinitis or strains of the rotator cuff
as a result of outlet impingement, cumulative tensile overload, and instability associated with internal impingement32-35(Fig 4) Patients with rotator cuff damage usually present
Figure 3 Arthroscopic repair of a Bankart lesion with suture anchors The patient is in the lateral decubitus position A, Elevator used to free the labrum, which has healed medially on the glenoid neck B, Mobilization of the dissected labrum onto the glenoid rim C, Fixation
of the labrum to the glenoid with a suture anchor after arthroscopic knot tying.
Trang 6with anterolateral shoulder pain that
worsens with continued activity In
ad-dition, they may report mild stiffness
and weakness in the involved
extrem-ity Physical examination should
in-clude provocative impingement
ma-neuvers and testing of ROM because
active internal rotation may be present
secondary to a tight posterior
cap-sule.32,33The Neer impingement sign
is pain elicited by forcing the arm into
a position of maximal forward
eleva-tion The Hawkins impingement sign
is pain elicited by forcible internal
ro-tation with the arm forward
elevat-ed to 90°, which produces pain when
the supraspinatus tendon impinges on
the coracoacromial ligament or ante-rior acromion Pain also may be present with resisted supraspinatus testing, although significant weakness
is not typically noted unless an un-derlying tear is present
Examination for concomitant gle-nohumeral instability is important be-cause treatment must be geared to-ward all etiologic factors Standard radiographic studies, including AP, outlet, and axillary views, typically
do not show any marked osseous ab-normalities MRI is the imaging study
of choice for evaluation of rotator cuff damage Increased signal in the ten-don and inflammation in the
sub-acromial space may be noted within the insertion of the supraspinatus ten-don, in cases of tendinitis MRI also may show evidence of partial or full-thickness tears (Fig 5), although these are not commonly observed in ado-lescents.2
Initial treatment of rotator cuff in-jury is nonsurgical, consisting of rest, ice, nonsteroidal anti-inflammatory drugs (NSAIDs), and physical ther-apy The physical therapy program focuses on ROM and strengthening
of the shoulder muscles to correct un-derlying muscular imbalance and to provide dynamic glenohumeral sta-bility Proper rehabilitation is crucial not only to relieve pain and expedite return to play but also to prevent pro-gression to partial or full-thickness tears that might require surgical in-tervention Stretching is important to establish and maintain full ROM, es-pecially in patients with tight poste-rior capsules with limited internal ro-tation A strengthening program is instituted to increase strength in the rotator cuff as well as in the scapular stabilizers During the acute phase of tendinitis, exercises should be per-formed below shoulder level to avoid rotator cuff outlet impingement, with gradual progression as symptoms
de-Table 1
Pitching Recommendations for the Young Baseball Player
Age Maximum Pitches per Game Maximum Games per Week
Reproduced with permission from Pasque CB, McGinnis DW, Griffin LY: Shoulder, in
Sullivan JA, Anderson ST (eds): Care of the Young Athlete Rosemont, IL: American
Academy of Orthopaedic Surgeons, and Elk Grove Village, IL: American Academy of
Pediatrics, 2000, p 347.
Figure 4 Swimmers subject their shoulders to excessive forces during both (A) the front crawl-stroke (cuff impingement, arrows) and (B)
the backstroke (anterior capsular tension) In panel B, the arrows indicate the pull of the rotator cuff on the proximal humerus (Adapted
with permission from Wilkens KE: Shoulder injuries: Epidemiology, in Stanitski CL, DeLee JC, Drez D Jr [eds]: Pediatric and Adolescent Sports
Medicine Philadelphia, PA: WB Saunders, 1994, p 181.)
Trang 7crease Usually, nonsurgical treatment
allows gradual return to competition
For patients who do not respond to
an initial 6- to 12-week period of
mod-ified activity and physical therapy, an
MRI should be considered to
evalu-ate for partial or full-thickness tears
and other intra-articular damage
Arthroscopic treatment of rotator
cuff injury is reserved for injuries that
do not respond to nonsurgical
man-agement; results have been mixed in
young athletes with regard to pain
re-lief and return to sports Surgical
suc-cess depends on the nature of the
un-derlying rotator cuff damage as well
as any associated problems, such as
instability or labral tears.2,35It is
portant to distinguish between
im-pingement and concomitant
under-lying instability because failure to
address these subtle instability
pat-terns may compromise functional
re-sults True outlet impingement is
ex-tremely rare in adolescents, who
typically present with secondary or
internal impingement as a result of
subtle instability patterns These
pat-terns may be related to rotator cuff fa-tigue, to superior labral anterior-posterior (SLAP) lesions involving the superior biceps–labral anchor complex,
or to true instability and are asciated with articular-sided partial-thickness rotator cuff tears Arthroscopic acro-mioplasty is rarely performed alone
in this population; rather, subacromial bursectomy and débridement are usu-ally accompanied by procedures that address the associated damage (ie, débridement of partial-thickness ro-tator cuff tears and repair of SLAP/
labral lesions).36Progressive ROM and strengthening exercises may be initi-ated early after surgery As a general rule, however, arthroscopy should be
a last resort in the treatment of rota-tor cuff injuries in the adolescent ath-lete and undertaken only when spe-cific, clearly defined damage can be addressed
Anterior Glenohumeral Instability
Anterior instability usually results from chronic overload injuries in the athlete engaged in overhead sports
Excessive, repetitive external rotation during the overhead motion places tremendous stress on the anterior cap-sular and ligamentous structures, causing microtrauma that leads to lig-amentous laxity Initially, the rotator cuff and periscapular muscles com-pensate However, these dynamic stabilizers fatigue with repeated ac-tivity, and anterior glenohumeral translation ensues, with subsequent development of instability Secondary impingement of the rotator cuff an-terosuperiorly against the coracoac-romial arch during forward flexion may occur, causing tendinitis or even undersurface tears.31Furthermore, as the humeral head translates anteriorly with shoulder abduction and exter-nal rotation, interexter-nal impingement of the rotator cuff also may occur33(Fig
6) Normally, with the shoulder in the apprehension position, the distance between the rotator cuff and the pos-terosuperior glenoid rim is small As
the static stabilizers become lax and the dynamic stabilizers fatigue, in-creased anterior glenohumeral trans-lation with the arm in the apprehen-sion position pinches the cuff against the posterosuperior glenoid rim, pro-ducing internal impingement Con-comitant posterior capsular contrac-tures caused by repetitive stress may further exacerbate the impinge-ment.5,24
Athletes typically present with de-creased throwing effectiveness and pain, especially during late cocking and early acceleration They also may report a “dead arm.” On examination, load-and-shift (Fig 7) and fulcrum tests may not demonstrate anterior laxity Mild anterior apprehension with a positive relocation test may be present, indicating internal impinge-ment Loss of internal rotation also may be present, secondary to a tight posterior capsule.5,6,17Athletes with associated rotator cuff damage may have appropriate findings Usually, in the absence of a traumatic injury, plain radiography shows no signif-icant abnormalities MRI may show increased signal within the posterior cuff, consistent with fraying in cases
of internal impingement, and if MRI
is performed with contrast medium,
it may show redundancy in the an-terior capsule Usually, labral damage
is not present unless there has been
a traumatic episode Routine use of MRI for instability secondary to over-use is not needed unless the clinician suspects associated damage Treatment of anterior instability begins with an initial period of rest followed by physical therapy and a home exercise program that empha-sizes strengthening and conditioning
of the rotator cuff, deltoid, and scap-ular muscles Both concentric and ec-centric exercises are included as well
as stretching of the posterior capsule
if tightness is present Improper throwing mechanics also must be cor-rected Athletes are allowed to return gradually to throwing once stability, strength, and endurance have
im-Figure 5 Oblique coronal MRI scan of the
shoulder after intra-articular injection of
gad-olinium, demonstrating partial-thickness
un-dersurface rotator cuff tear (arrow)
(Repro-duced with permission from Kingston S:
Diagnostic imaging of the upper extremity,
in Jobe FW [ed]: Operative Techniques in
Up-per Extremity Sports Injuries St Louis, MO:
Mosby, 1996, p 35.)
Trang 8proved (usually within 3 months).
With well-supervised physical
ther-apy, most will be able to return to their
prior level of activity in 6 months.2,37
If symptoms persist despite 4 to 6
months of well-supervised
nonsurgi-cal management, surgery may be
in-dicated Arthroscopy may reveal
stretching of the inferior
glenohumer-al ligament and anterior capsule,
la-bral fraying, or undersurface cuff
tears.38,39Débridement alone of the
ro-tator cuff and posterosuperior glenoid
is inadequate to address the
under-lying pathology; either open or ar-throscopic anterior capsuloligamen-tous reconstruction is recommended for the best functional outcomes An arthroscopic anteroinferior suture capsulorrhaphy is often sufficient to address the underlying damage, and current arthroscopic techniques have results comparable to those of open stabilization.29,36Arthroscopy allows excellent visualization of the capsu-lolabral complex with minimal inva-siveness, which can decrease morbid-ity and, more important, minimize
external rotation loss
postoperative-ly, which is critical in the overhead athlete The lax inferior glenohumeral ligamentous complex and anteroin-ferior capsule are imbricated arthro-scopically and tightened using mul-tiple nonabsorbable sutures Suture anchors may be placed along the gle-noid rim to repair a labral detachment
as well as to perform capsular plication24-27(Fig 3, C)
Postoperative isometric strength-ening exercises are started early Sling immobilization may be discontinued after 10 to 14 days, followed by pro-gressive ROM and strengthening ex-ercises The deltoid, rotator cuff, and scapular muscles are targeted to pro-vide dynamic stability and restore nor-mal glenohumeral and scapulothoracic rhythm Return to full, unrestricted
Figure 6 Progression of injury in internal impingement A, The normal position of the
hu-meral head in the glenoid during abduction to 90° in the scapular plane and maximal
ex-ternal rotation B, Anterior translation (curved arrow) leads to subluxation of the humeral
head and hyperangulation C, This in turn leads to skeletal, labral, and tendinous lesions.
Inset: The posterosuperior region of the glenoid (broken line) is where impingement occurs.
(Reproduced with permission from Jobe CM, Pink MM, Jobe FW, Shaffer B: Anterior
shoul-der instability, impingement, and rotator cuff tear: Theories and concepts, in Jobe FW [ed]:
Operative Techniques in Upper Extremity Sports Injuries St Louis, MO: Mosby, 1996, p 175.)
Figure 7 Load-and-shift test for anterior in-stability of the shoulder With the patient
seat-ed, the examiner stabilizes the scapula with one hand and then applies a compressive force to the glenohumeral joint (arrows) and measures anteroposterior excursion (dotted lines) (Adapted with permission from Mc-Farland EG, Shaffer B, Glousman RE, Conway
JE, Jobe FW: Anterior shoulder instability, im-pingement, and rotator cuff tear: Clinical and
diagnostic evaluation, in Jobe FW [ed]:
Op-erative Techniques in Upper Extremity Sports In-juries St Louis, MO: Mosby, 1996, p 185.)
Trang 9activity may take up to 6 to 12 months
in the throwing athlete
Posterior Glenohumeral
Instability
Although not as common as
ante-rior pathology, posteante-rior instability is
increasing in incidence as a result of
chronic microtrauma to the posterior
structures from repetitive overhead
activity Less commonly, a single
trau-matic episode may result in
posteri-or capsular injury and subluxation,
which may be missed if lateral and
axillary radiographs are not
ob-tained.20Repetitive eccentric
contrac-tion during the deceleracontrac-tion and
follow-through stages of throwing
stretches the posterior capsule and
produces microtears within the
pos-terior cuff Together, these factors can
contribute to development of
poste-rior instability.37,40Typically, athletes
present with pain during the
decel-eration phase of throwing, and pain
may be elicited on examination with
the arm in flexion, adduction, and
in-ternal rotation as the shoulder is
pos-teriorly subluxated Usually, in the
ab-sence of a posterior labral tear, neither
plain radiography nor MRI shows
any damage
Initial treatment is nonsurgical and
includes physical therapy to
strength-en the posterior rotator cuff and
scapu-lar muscles, especially the
infraspina-tus, teres minor, and posterior deltoid
Proper throwing mechanics are
em-phasized along with leg and trunk
strengthening to transfer some of the
throwing stresses to the lower
extrem-ities Usually, athletes are able to
re-turn to throwing after 4 to 6 months
of rehabilitation Recurrent or
recal-citrant symptoms may require
surgi-cal intervention, with either open or
arthroscopic posterior capsulorrhaphy
to imbricate the redundant posterior
capsule.41,42
Multidirectional Shoulder
Instability
Multidirectional instability (MDI)
is characterized by symptoms of
sub-luxation in more than one direction (anterior, posterior, or inferior) in the absence of a major traumatic event
Commonly, MDI affects athletes par-ticipating in sports that involve repet-itive shoulder abduction and exter-nal rotation Competitive swimmers, especially those swimming the but-terfly stroke, and gymnasts often exhibit symptoms of MDI.2,31,37
Affect-ed athletes typically possess under-lying physiologic glenohumeral lax-ity that is exacerbated by repetitive microtrauma or by a traumatic insult, resulting in inability to maintain dy-namic stability Athletes may report
a dead arm as well as a sensation of the shoulder dislocating and sponta-neously reducing Symptoms may be vague but usually correlate with the direction of instability Athletes with anterior instability describe pain with the arm in the overhead, abducted, and externally rotated position Those with posterior instability typically re-port pain with the arm in the forward-elevated and internally rotated posi-tion, such as when pushing open heavy doors Patients with inferior in-stability may report discomfort when they carry heavy objects with the arm
at the side Occasionally, secondary rotator cuff symptoms also may be re-ported in conjunction with instabil-ity.31
On physical examination, general-ized ligamentous laxity may be present, with findings such as elbow and metacarpophalangeal joint hy-perextension The affected shoulder demonstrates increased
glenohumer-al translation in multiple directions
Comparing the affected shoulder with the contralateral shoulder is mandatory, and there may be multi-ple positive findings on load-and-shift, relocation, and fulcrum tests and apprehension maneuvers Typ-ically, a sulcus sign significant for in-ferior laxity is also present It is im-portant to determine the direction or directions of increased
glenohumer-al translation that actuglenohumer-ally replicate the patient’s symptoms because
lax-ity does not necessarily indicate in-stability Imaging studies are often un-remarkable; plain radiographs usually show no osseous abnormalities unless the patient has had an actual dislo-cation, in which case a humeral head
or glenoid defect may be observed MRI arthrography with intra-articular contrast medium may show a redun-dant or patulous capsule with in-creased capsular volume, usually with
no evidence of labral damage Initial treatment consists of rest and wet heat before, and ice after, ac-tivity Most importantly, the patient should begin rehabilitation that em-phasizes strengthening of the rotator cuff, deltoid, and scapulothoracic musculature to provide dynamic sta-bility Surgery is indicated when there are residual symptoms after a min-imum of 6 months of therapy Usu-ally, the loose redundant capsule is reconstructed and imbricated in the direction or directions of predomi-nant instability (anterior, inferior, or posterior, or combinations of these) Because current arthroscopic capsu-lorrhaphy techniques can achieve re-sults similar to those of open inferior capsular shifts, these are typically pre-ferred in overhead athletes.43,44 Ther-mal energy to “shrink” the redundant capsule is not indicated, given the failure rates for MDI;45-47rather, su-ture capsulorrhaphy techniques to eliminate redundancy by imbricating the capsule and reducing its overall volume are preferable Occasionally, these techniques are augmented with suture anchors along the glenoid rim for additional fixation.43,44Suture cap-sulorrhaphy may be accomplished for the anterior and posterior capsule as well as the rotator interval, depend-ing on the nature of the injury Patients should be counseled re-garding treatment goals, including ini-tial shoulder “tightening,” during which the shoulder is immobilized for
a period of 2 to 4 weeks while gentle isometric exercises are performed This
is followed by gradual increase in ROM and strengthening over an
Trang 10ex-tended period, with return to
unre-stricted activity by 6 months
Injuries of the Elbow
Elbow injuries occur more
frequent-ly than shoulder injuries, with 50%
to 75% of adolescent baseball players
reporting elbow pain.2Most of these
injuries result from chronic repetitive
stresses; they can be limited by
de-creasing the frequency and duration
of throwing and by improving
pitch-ing mechanics Although these
inju-ries are most common in pitchers,
they also occur frequently in other
overhead athletes.2,21
Little League Elbow
Initially described as an avulsion
fracture of the medial epicondyle,
Lit-tle League elbow is a general term
re-lating to several abnormalities in the
elbow of the young overhead athlete,
including medial epicondylar
avul-sion, medial epicondylar apophysitis,
and accelerated apophyseal growth
with delayed closure of the
epicondy-lar growth plate.2,10,11,21Little League
elbow results from repetitive valgus
stresses and tension overload of the
medial structures Repetitive
contrac-tion of the flexor-pronator
muscula-ture stresses the chondro-osseous
or-igin, leading to inflammation and
subsequent apophysitis Affected
ath-letes are usually younger than age 10
years and typically report a triad of
medial elbow pain, decreased
throw-ing effectiveness, and decreased
throwing distance.2,10,11,21 Patients
may exhibit medial swelling, focal
tenderness over the medial
epi-condyle, and occasional flexion
con-tractures Although results of plain
ra-diography are sometimes normal,
radiographic changes include
irreg-ular ossification of the medial
epi-condylar apophysis early in the
dis-ease process, followed by accelerated
growth, marked by apophyseal
en-largement, separation, and
eventual-ly fragmentation.2,10,11,21
Generally, treatment consists of 2
to 4 weeks of rest and NSAIDs, fol-lowed by stretching and strengthen-ing exercises of the elbow, with grad-ual return to throwing at 6 weeks if the athlete is symptom free.10 Occa-sionally, symptoms may persist for extended periods, typically because
of inadequate rest or activity modi-fication In these instances, brief splint
or cast immobilization may be nec-essary, and the patient should not re-sume throwing until the following season.10Other factors contributing to exacerbation of symptoms include a high number of pitches thrown and innings pitched as well as improper throwing mechanics, all of which should be addressed and monitored closely in young overhead athletes
Ulnar Collateral Ligament Injuries and Valgus Instability
UCL injuries are uncommon in skeletally immature athletes Pa-tients with this injury report medial elbow pain that is exacerbated dur-ing the late cockdur-ing and acceleration stages of throwing Examination for valgus stability is performed with the elbow flexed 25° to 30° to unlock
the olecranon from its fossa as a val-gus stress is applied; this maneuver tests the anterior band of the ante-rior bundle of the UCL The poste-rior band is tested by the milking maneuver (Fig 8), performed by pulling the patient’s thumb with the forearm supinated, shoulder ex-tended, and elbow flexed more than 90°.47Usually, results of plain radi-ography are normal unless late changes associated with chronic lax-ity and valgus extension overload have developed Valgus stress views also may be obtained to assess sta-bility; a medial joint opening >2 mm wide indicates instability (Fig 9) However, MRI is more useful and provides good visualization of the UCL as well as of the surrounding structures19(Fig 10) Recently, com-puted tomography arthrography also has been used adjunctively to evaluate undersurface tears of the UCL as well as other intra-articular structures
Initial treatment of UCL injuries in-cludes a short period of immobiliza-tion coupled with ice and NSAIDs to control pain Once the acute inflam-mation subsides, a supervised
ther-Figure 8 Elbow examination for medial instability A, The examination for valgus stability
is done with the elbow flexed 25° to 30° (to unlock the olecranon) testing the anterior band
of the anterior bundle of the ulnar collateral ligament The examiner firmly grasps the
pa-tient’s elbow and forearm applying varus-valgus stress while palpating the UCL B, The
milk-ing maneuver tests the posterior band of the anterior bundle of the ulnar collateral ligament The maneuver is performed by applying downward and valgus stress with the forearm su-pinated, and elbow flexed more than 90° (Adapted with permission from Kvitne RS, Jobe
FW: Ligamentous and posterior compartment injuries of the elbow, in Jobe FW [ed]:
Oper-ative Techniques in Upper Extremity Sports Injuries St Louis, MO: Mosby, 1996, p 415.)