DIFFERENTIAL DIAGNOSIS OF SHOULDER
INJURIES IN SPORTS
STEPHEN OWENS, MD, and JOHN M. ITAMURA, MD
The shoulder is very susceptible to injury in sports. Its use as a battering ram in collision sports, frequent falls and
direct blows, and the demanding combination of power, flexibility and repetition in overhand sports make this joint
highly vulnerable. The complex anatomy of the shoulder creates a challenge for the clinician faced with an injury, be
it chronic or acute, and many symptoms overlap. Chronic symptoms are often vague and nonspecific, highlighting
the importance of a careful history and physical examination. This review article looks at various shoulder injuries
that are relevant to sports, and discusses their differential diagnosis.
KEY WORDS: Shoulder, injury, sports, athlete, diagnosis
Athletic injuries to the shoulder are both common and
unique, and even for the most experienced examiner they
can be difficult to diagnose and manage. Most occur from
either direct or indirect trauma or result from repetitive
use. Fractures, dislocations, sprains, and tendon ruptures
are everyday occurrences in contact sports that produce
frequent falls and collisions, whereas chronic injury is the
product of strain and fatigue from overuse. Patterns
develop across sports that place similar demands on the
shoulder and that require similar motion. These injury
patterns are most prevalent in overhand throwers. There is
an ongoing attempt to better understand these challenging
clinical problems, and the treatment of shoulder injuries is
an evolving science. The objective of this article is to review
the cause of shoulder pain and injury resulting from both
trauma in the contact athlete and from overuse in the
overhead athlete.
The diagnosis of a shoulder injury requires a detailed,
yet focused, history and physical examination, accompanied by a fundamental knowledge of the anatomy. These
are the most useful tools in eliciting the clinical features of
tissue injury, which can be quite subtle. The ability to
correlate the history with the physical examination depends on understanding the mechanism of injury and
being able to reproduce the symptoms clinically. Knowledge of the patient's participation, the movement and
positions that cause pain, the symptoms described, and
their temporal relationships and duration is important, in
particular when a chronic injury presents. The age of the
patient can help identify certain risk factors. For instance,
the older athlete is more prone to degenerative tendinopathy of the rotator cuff with subacromial impingement,
whereas the younger athlete, with greater tissue laxity, is
more prone to instability.
From USC Orthopaedic Surgery Associates, Los Angeles, CA.
Address reprint requests to Steve Owens, MD, USC Orthopaedic
Surgery Associates, 1510 San Pablo, Suite 322, Los Angeles, CA
90033-4608.
Copyright © 2000 by W.B. Saunders Company
1060-1872/00/0804-0001 $10.00/0
doi:10.1053/otsm.2000.17773
Shoulder pain can be a misleading symptom. Referred
pain from cervical radiculopathy is common, and an
examination of the cervical spine, including provocative
maneuvers such as the Spurling test and cervical traction,
as well as a sensory and motor neurologic examination,
evaluates these lesions. Cardiac ischemia, pericarditis,
intra-abdominal pathologic conditions, or thoracic outlet
syndrome can present as shoulder pain, as can carpal
tunnel syndrome and other peripheral nerve entrapment
syndromes. Bone and soft tissue tumors are often associated with continuous, irregular, deep pain, along with
constitutional symptoms such as fever, weight loss, malaise, or fatigue. A brief review of systems will help
determine the relevance of these entities in the evaluation.
ACUTE SHOULDER INJURIES
Acute injury prevention has greatly improved with the
development of sophisticated equipment and protective
gear, but the tremendous forces generated in collision
sports continue to cause injury. The traumatic shoulder can
present a challenging clinical encounter, especially when
there is inhibition and guarding. Knowledge about the
position of the arm and forearm at the time of injury, the
degree of muscle contraction or relaxation, and the direction and momentum of the athlete helps determine the
type and severity of the injury. Additionally, information
about the mechanism and force of the injury, giving-way
sensations, pops or snaps, or numbness and paresthesias
helps describe the pathoanatomy. Often a delayed examination is useful to allow the acute swelling and pain to
resolve.
Traumatic injuries to the shoulder can be categorized
into osseous, soft tissue, and nerve lesions. The clavicle is
the most frequently fractured bone and occurs by either a
direct or indirect mechanism. A history of a fall directly
onto the tip of the shoulder is typical, as is a history of a fall
onto the outstretched hand. There is little difficulty in
making the diagnosis of a clavicle fracture. Associated soft
tissue disruption, particularly that to the coracoclavicular
ligaments, can be a troublesome feature of the distal
clavicle fracture, and appropriate management mandates
Operative Techniques in Sports Medicine, Vol 8, No 4 (October), 2000: pp 253-257
253
an accurate classification. Proximal humerus fractures
occur infrequently. Fracture geometry can be complex, and
a computed tomography (CT) scan may be required to
realize the extent of the bony injury. A fracture-dislocation
involving the greater tuberosity indicates a disruption of
the anterior capsulolabral complex and a likely rotator cuff
tear.
Fractures of the scapula involving the body, glenoid
neck or rim, coracoid, and acromion are uncommon in
sports, and usually have associated injuries. An anteroposterior (AP), axillary, and Y-view are necessary to avoid
missing these lesions. Anterior or anteroinferior glenoid
rim fractures typically represent a bony Bankart lesion,
with associated anterior instability. A history of a dislocation confirms this. The acromion fracture occurs after a fall
onto the shoulder or a direct blow. Either the West Point or
axillary view is most helpful in characterizing these fractures. Isolated coracoid process fractures are very uncommon and in the literature are described only in case
reports. 16 This injury produces pain anteriorly that worsens with deep inspiration. Radiographically they are best
detected with either the axillary view or a 30 ° cephalic tilt
view. Resisted arm flexion and forearm supination recreates pain, and the mechanism of injury appears to be
indirect with the arm abducted, extended, and oriented
backward.
Stress fractures about the shoulder, though exceedingly
rare, are considered when symptoms are vague and atypicaU 3 Bony tenderness of insidious onset that is slow to
resolve may represent such an injury. There have been 2
reported cases of stress fracture to the clavicle, confirmed
with bone scan. These were in a javelin thrower and a
diver. Scapular stress fractures have been reported, one
along the superomedial edge in a jogger who was using
hand-held weights, another at the base of the acromion in
an offensive lineman, and another at the coracoid base in a
trap shooter. Bone scans and magnetic resonance imaging
(MRI) scans remain the best radiographic modalities.
Soft tissue injuries caused by blunt or indirect trauma are
routine occurrences in contact and collision sports. Soft
tissue contusions over the deltoid, and the trapezius at the
base of the neck, regularly occur in tacklers, and not
uncommonly lead to myositis ossificans. A history of direct
trauma to the region associated with local tenderness and
ecchymosis helps differentiate these injuries from the more
chronic cuff tendonitis, and provocative tests for rotator
cuff pathology are generally negative. Myositis, when
present, can be exquisitely tender and painful, and radiographically appears as lacy peripheral ossification with
soft tissue swelling.
An athlete with an acromioclavicular (AC) joint sprain
will describe a fall directly onto the shoulder, a direct blow
to the shoulder, or a fall on an outstretched arm. Local
tenderness and excessive joint mobility are good clinical
indicators, but radiographs are needed to rule out a distal
clavicle fracture. Weighted radiographs are rarely needed,
because a good history and physical examination are
usually sufficient to make the diagnosis. Localized pain
with elevation of the arm occurs because of the pull of the
deltoid and trapezius on the injured joint, and cross-body
adduction compresses the joint, causing pain. Nondisplaced type I sprains should be differentiated from rotator
254
cuff pathology, glenohumeral subluxation, and burner
syndrome.
Glenohumeral dislocations are most common anteriorly
and inferiorly. The classic traumatic dislocation causes an
avulsion of the anterior-inferior labrum and ligamentous
restraints and varying degrees of plastic deformation to the
anterior capsule. In certain instances, subscapularis tearing
occurs. A violent extension of the abducted, externally
rotated arm is the most frequent mechanism. Clinically, the
arm is held away from the body and externally rotated,
and the posterior deltoid contour is flattened or absent. A
first-time dislocator occasionally will reduce spontaneously before treatment, although this is the exception.
Axillary nerve injury can be a cause of late deltoid
dysfunction, and brachial plexus injuries may occur, so a
thoroughneurologic examination before and after intervention is warranted. The diagnosis is usually clinical, but
orthogonal radiographs in AP and lateral planes are
necessary to rule out associated fractures and to determine
the direction of dislocation. Either a scapular Y view or a
Velpeau lateral is useful when an axillary lateral view is
not accomplished. Close attention to the glenoid will avoid
missing a bony Bankart lesion. A West Point view will help
visualize this, although a CT scan will provide more
information about the size and geometry of the fracture, as
it will for a large Hill-Sachs lesion.
Posterior dislocations caused by trauma are much less
common and usually occur from a fall onto the flexed,
adducted, and internally rotated arm. Less deformity is
evident, and the same radiographs are necessary to confirm the diagnosis. The arm is internally rotated and held
at the side. This posturing is not unique and contributes to
the reported 50% misdiagnosis rate. A good lateral radiograph, part of every trauma series, cannot be overstated. A
reverse Hill-Sachs lesion can be appreciated with an
external rotation radiograph, but, again, is best characterized by a CT scan.
Traumatic rotator cuff tears occur rarely in athletes
younger than 35 years and are best understood as a
consequence of degeneration and impingement in the
older athlete. Acute ruptures result from a violent mechanism in which the torn muscle-tendon unit maximally
contracts against an eccentric load. Cuff weakness is best
shown by the supraspinatus test and resisted external
rotation at the side with injury to either the supraspinatus
or infraspinatus, respectively. Isolated subscapularis tears
show weakness on the lifboff test, which is performed by
the patient's hand pushing off from the back. Pain and
tenderness are usually found over the greater tuberosity or
underneath the anterolateral acromion with a tear of the
supraspinatus. Subscapularis tears produce anterior shoulder pain and tenderness. Anterior instability may be
contributory to these latter injuries, and the apprehension
sign is commonly positive. A subluxed biceps frequently
accompanies a tear of the subscapularis tendon, particularly when the tear extends into the rotator interval. An
irritated biceps tendon is shown by a positive Yergason
and Speed's test combined with direct tenderness along
the bicipital groove. O'Brien's test also may be positive.
Acute rotator cuff tears, like degenerative tears, commonly
produce a dull ache and cause night pain. The differential
includes an AC joint sprain, deltoid strain, subluxation,
OWENS AND ITAMURA
isolated biceps lesions, or suprascapular neuropathy. It is
therefore important to sort out true weakness from painful
inhibition.
Acute nerve injuries about the shoulder have been
reported in a variety of different sports. Perhaps the most
susceptible and troublesome is the axillary nerve, which is
injured in 9% to 18% of anterior shoulder dislocations.
Blunt trauma and hematoma formation also have been
implicated in cases of axillary neuropathy. 2° Deltoid atrophy occurs as a consequence of chronic denervation,
though in the acute setting weakness is the most pronounced finding. Sensation is often preserved and is not a
reliable indicator of nerve injury. An isolated axillary nerve
injury is differentiated from a more proximal lesion along
the brachial plexus, and a rotator cuff tear, especially after a
traumatic shoulder dislocation. Electromyograph/nerve
conduction study (EMG/NCS) are the most useful diagnostic tools. 26
The suprascapular nerve may be injured by a blow to the
superior shoulder or, more commonly, from acute stretching. The location of the injury defines the motor involvement to the supraspinatus and infraspinatus. Clinical
similarities with rotator cuff tears make differentiating
these two lesions challenging. Suprascapular neuropathy
generally produces vague aching pain posterosuperiorly
but can coexist with impingement signs and symptoms.
Atrophy, weakness, normal sensation, and a preserved
deltoid are not unique to either diagnosis. EMG/NCS are
needed to confirm the diagnosis.
Scapular winging indicates weakness of the serratus
anterior, which is innervated by the long thoracic nerve.
Injury to this nerve was first reported in 1937 and has been
found to occur in sports ranging from archery to football. TM
It is most commonly a traction phenomenon, though
contusion from a direct blow is possible. Winging of the
scapula is the classic physical examination finding and is
best demonstrated by having the patient perform a standing pushup against the wall. Scapular winging may not
occur for several weeks after injury until the trapezius
stretches out. Thus, the early findings are often limited to
aching/burning pain in the posterior shoulder with associated weakness on arm elevation and abduction. EMG/
NCS are, again, the necessary tests.
CHRONIC INJURIES
The mechanism of chronic shoulder injury in overhand
athletes is a complicated, and perhaps controversial, topic.
The glenohumeral joint is the most mobile joint in the body,
and its anatomy is variable and complex. The intricate
coordination of motion and stability allows for remarkable
athletic versatility. Repetitive motion at or beyond its
physiologic range, which is typical of most overhead
sports, threatens the integrity of the soft tissue stabilizers
in their efforts to maintain joint congruity. Most overuse
injuries are now understood as the result of a breakdown
in joint stabilization. A large volume of literature has been
devoted to understanding the mechanism of shoulder
instability in athletes, and our knowledge continues to
evolve.
This forceful, repetitive strain combines with muscle
fatigue and poor scapulohumeral rhythm to create a specDIFFERENTIAL DIAGNOSIS OF SHOULDER INJURIES
trum of capsulolabral pathology. Excessive translation of
the humeral head on the glenoid results. There are varying
theories as to the cause of this instability phenomenon,
from stretching of the anterior capsule and microinstability, to the circle concept, with a loss of capsular integrity
caused by posterosuperior labral peelback. 19 Labrum, capsule, biceps anchor, rotator cuff, and coracoacromial arch
pathologic conditions are common in these athletes. Age
has significant bearing on the type of lesion seen. Tissue
injury in the athlete over age 35 years usually relates to
degenerative processes, in contrast to the younger athlete,
in w h o m instability is the primary contributor. Nerve
compression also can cause pain and can mimic symptoms
associated with cuff and deltoid pathology.
Important aspects of the history, aside from age1 include
type of sport, handedness, location, duration and character
of pain, mechanical symptoms such as clicking or catching,
and the nature of onset. Valuable information is gained
from knowing the relationship of pain to the specific
activity, as is knowing at what phase during the throwing
motion pain occurs and the location of the pain. Also
valuable is knowledge about training techniques, which, if
unsupervised and performed incorrectly, can propagate
the injury.
Numerous lesions cause pain anteriorly in the shoulder.
A common consequence of anterior instability is anterior
shoulder pain, and pain that occurs in the late cocking or
early acceleration phase of the throwing motion is convincing. Varying degrees of laxity may be appreciated on
physical examination, but a positive apprehension sign
and relocation test is usually diagnostic. Pathologic conditions that can be associated with anterior instability or
subluxation, aside from a disruption of the anterior labrum
and capsule, include a rotator interval tear or even a partial
subscapularis tear. Again, biceps instability and tendonitis
frequently result from this. These 3 lesions also cause pain
anteriorly and are suspected in the face of continued
weakness and pain on internal rotation, pain with provocative biceps tests as previously described, and tenderness
anteriorly and along the bicipital groove.
Lesions of the superior labrum and biceps anchor may
produce pain anteriorly. Commonly the thrower will give a
history of painful catching or clicking in the abducted,
externally rotated position. Several different maneuvers
have been described for identifying these SLAP lesions,
most of which create tension along the long head of the
biceps with the humerus internally rotated and adducted.
Deltoid muscle strains in the anterior head will be point
tender over the site of injury and possibly ecchymotic,
painful with forward elevation, and the history is usually
straightforward. Poorly localized anterior shoulder pain
associated with nondermatomal upper extremity paresthesias may represent compression of the axillary nerve as it
passes through the quadrilateral space. Symptoms are
most pronounced when the shoulder is placed in the
abducted, externally rotated position. Rare but seen in the
young overhead athlete, the quadrilateral space syndrome
is best diagnosed with an arteriogram. Occlusion of the
posterior humeral circumflex artery, which courses with
the axillary nerve, is seen as the arm achieves the position
of abduction and external rotation.
Pain over the lateral deltoid and subacromial region
255
raises suspicion for either rotator cuff injury or impingement and bursitis. Overuse in the younger athlete from
throwing, swimming, or other overhead activities can
fatigue and injure the cuff, causing rotator cuff tendonitis.
Increased training, improper mechanics, poor conditioning, or a combination thereof are suspected. Achy pain
m a d e worse with abduction or forward flexion of the arm,
tenderness along the cuff insertion and subacromial region, and impingement signs are usually found. Symptoms that persist despite a course of physical therapy and
anti-inflammatories are suggestive of a rotator cuff tear,
particularly if the history elicits disruptive night pain.
Other causes of lateral shoulder pain include calcific
tendinopathy and suprascapular nerve compression. Calcific tendinopathy can be marked by severe, unrelenting
burning pain that is either abrupt in onset or more gradual
in onset and progressive. Radiographs aid in making this
diagnosis. Suprascapular neuropathy from compression at
the transverse scapular ligament or the spinoglenoid notch
m a y initially be difficult to distinguish from cuff pathology.
Pain is vague but often lateral and posterior, and weakness
on elevation and external rotation mimics a rotator cuff
tear. The y o u n g e r athlete with persistent weakness and
evolving atrophy of either the infraspinatus or both the
infraspinatus and supraspinatus is rarely found to have a
large rotator cuff tear, and a suprascapular nerve lesion
should be suspected. 2,18,25 The older athlete with this
history has a cuff tear until proved otherwise. The appropriate imaging and electrodiagnostic studies facilitate the
diagnosis.
Posterior shoulder pain can be a s y m p t o m of instability,
glenohumeral arthritis, posterior deltoid or proximal triceps strain, or lower cervical nerve root compression.
Posterior glenohumeral instability, like its anterior counterpart, is a positional p h e n o m e n o n that is as difficult to
manage as it is to diagnose. Offensive linemen w h o are
repeatedly pushing off with their arms against defensive
players are prone to developing posterior instability, frequently in players w h o display ligamentous laxity. Pain
with the arm flexed to 90 ° and internally rotated is usually
present, and pain with a posterior drawer to the glenohumeral joint is provocative. Interestingly, s u b t l e anterior
instability c o m m o n l y produces posterior shoulder pain.
The abducted, externally rotated arm can pinch the undersurface of the rotator cuff insertion, and even slight
anterior translation can drive this insertion into the posterior glenoid, d a m a g i n g the posterior labrum with repeated
episodes. On examination, pain posteriorly in this position
indicates this pathologic condition.
Posterior pain in the older athlete could represent
degenerative joint disease, which m a y be seen radiographically. Crepitation, stiffness, and atrophy m a y exist, though
cuff strength and integrity is usually preserved. Pain
caused by scapular grinding presents posteriorly, and
palpable crepitation makes this an easy diagnosis.
Superior shoulder pain that radiates along the trapezius
and d o w n the arm to the h a n d suggests a cervical origin.
Spurling's test m a y contribute to an accurate diagnosis,
although h a n d weakness, dermatomal sensory loss, and
diminished reflexes m a y be the most specific objective
findings. An athlete with cervical radiculitis typically
displays some degree of neck stiffness. A tender AC joint
256
combined with pain on flexion and adduction of the
h u m e r u s is consistent with AC joint arthritis, although
distal clavicle osteolysis presents with the same type of
symptoms. Radiographs are needed to differentiate these
lesions.
SUMMARY
Shoulder injuries are c o m m o n problems in all types of
sports. There can be a good deal of variability in h o w
symptoms are expressed from individual to individual,
and part of the challenge in understanding the injury is
being able to interpret the athlete's complaints as they
relate to examination findings and the conditions that
produce the symptoms. The history is particularly important because the sensitivity and specificity of m a n y aspects
of the examination are variable. A relaxed patient and a
systematic evaluation is the best w a y to be thorough.
Radiographs and even MRIs are frequently negative in soft
tissue problems in the y o u n g athlete. This underscores the
importance of a good examination. There m a y be some
utility in using contrast-enhanced MRIs to look at labral
pathologic conditions, cysts, or ganglions, but this information is certainly less useful than the patient's description of
symptoms and the examiner's findings. With this awareness, we can manage these injuries with more confidence.
REFERENCES
1. Anderson T: Difficult sports-related shoulder fractures. Clin Sports
Med 9:31-37, 1990
2. Black KP, Lombardo JA: Suprascapular nerve injuries with isolated
paralysis of the infraspinatus.Am J Sports Med 18:225-228, 1990
3. Brukner P: Stress fractures of the upper limb. Sports Medicine
26:415-424, 1998
4. Burkhart SS, Morgan CD, Kibler WB: Shoulder injuries in overhead
athletes: The dead arm revisited. Clin Sports Med 19:125-155,2000
5. Ellen MI, SmithJ: Musculoskeletalrehabilitation and sports medicine
(shoulder and upper extremity injuries). Arch Phys Med Rehabil
80S:50-58,1999
6. Glousman R: Electromyographicanalysis and its role in the athletic
shoulder. CORR288:27-34, 1993
7. Gowan ID, lobe FW, Tibone JE, et al: A comparative electromyographic analysis of the shoulder during pitching. Am J Sports Med
15:586-590,1987
8. Hawkins RJ, Kennedy JC: Impingement syndrome in athletes. Am J
Sports Med 8:151-158, 1980
9. Ho CP: MR imaging of rotator interval, long biceps, and associated
injuries in the overhead-throwing athlete. MRI Clin North Am
7:23-36, 1999
10. Hovelius L, Augustini BG, Fredin OH, et al: Primary anterior
dislocation of the shoulder in young patients. J Bone Joint Surg Am
78:1677-1684, 1996
11. Hoyt WA: Etiology of shoulder injuries in athletes. J Bone Joint Surg
Am 49:755-766, 1967
12. Huber WP, Putz RV: Periarticular fiber system of the shoulder joint.
Arthroscopy 13:680-691, 1997
13. Hulstyn MJ, Fadale PD: Shoulder injuries in the athlete. Clin Sports
Med 16:663-679, 1997
14. lobe FW, Bradley JP: The diagnosis and nonoperative treatment of
shoulder injuries in athletes. Clin Sports Med 8:419-437, 1989
15. lobe FW, Moynes DR: Delineation of diagnostic criteria and a
rehabilitation program for rotator cuff injuries. Am J Sports Med
10:336-339, 1982
16. Mariani PP: Isolated fracture of the coracoidprocess in an athlete.Am
J Sports Med 8:129-130, 1980
OWENS AND ITAMURA
17. McMaster WC: Ankerior glenoid labrum damage: A painful lesion in
swimmers. Am J Sports Med 14:383-387, 1986
18. Mendoza FX, Main K: Peripheral nerve injuries of the shoulder in the
athlete. Clin Sports Med 9:331-341, 1990
19. Morgan CD, Burkhart SS, Patmeri M, et al: Type II SLAP lesions:
Three subtypes and their relationships to superior instability and
rotator cuff tears. Arthroscopy 14:553-565, 1998
20. Perlmutter GS, Apruzzese W: Axillary nerve injuries in contact sports.
Sport Medicine 26:351-361, 1998
21. Redler MR, Juland LJ, McCue FC III: Quadrilateral space syndrome in
a throwing athlete. Am J Sports Med 14:511-513, 1986
DIFFERENTIAL DIAGNOSIS OF SHOULDER INJURIES
22. Roger B, Skaf A, Hooper AW, et al: Imaging findings in the dominant
shoulder of throwing athletes: Comparison of radiography, arthrograph?, CT arthrography, and MR arthrography with arthroscopic
correlation. AJR 172:1371-1380, 1999
23. Rowe CR, Zarins B: Recurrent transient subluxation of the shoulder. J
Bone Joint Surg Am 63:863-871, 1981
24. Schickendantz MS, Ho CP, Keppler L, et al: MR imaging of the
thrower's shoulder. MRI Clin North Am 7:39-48, 1999
25. Silliman JF, Dean MT: Neurovascular injuries to the shoulder complex. J Orthop Sports Phys Ther 18:442-448, 1993
26. Wilbourn AJ: Electrodiagnostic testing of neurologic injuries in
athletes. Clin Sports Med 9:229-245, 1990
257