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Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
Distal Clavicular Osteolysis
A Review of the Literature
Ran Schwarzkopf, M.D., M.Sc., Charbel Ishak, M.D., Michael Elman, M.D.,
Jonathan Gelber, M.D., David N. Strauss, M.D., and Laith M. Jazrawi, M.D.
Abstract
Acute distal clavicular osteolysis was first described in 1936.
Since then, distal clavicular osteolysis (DCO) has been separated
into traumatic and atraumatic pathogeneses. In 1982 the
first series of male weight trainers who developed ADCO was
reported. The association of weightlifting and ADCO is especially
important considering how routine a component weights
are to the male athlete’s training.The pathogenesis of DCO has
oftenbeendebated.The mostwidelyacceptedetiologyinvolvesa
connection between microfracturesof thesubchondral bone and
subsequent attempts at repair, which is consistent with repetitive
microtrauma. Symptoms usually begin with an insidious aching
pain in theAC region that is exacerbated by weight training. On
examination,patients havepointtenderness overtheaffectedAC
joint and pain with a cross-body adduction maneuver.Although
DCO may seem like an easy and quick diagnosis, one must rule
out other possibilities. Avoidance of provocative maneuvers,
modification of weight training techniques, ice massage, and
nonsteroidal anti-inflammatory drugs (NSAID) constitute the
basis of initial treatment. Much of the literature supports the
Ran Schwarzkopf, M.D., M.Sc., is a Resident in the Department
of Orthopaedic Surgery, NYU Hospital for Joint Diseases. Charbel
Ishak, M.D., is a Research Physician, Musculoskeletal Research
Center, Department of Orthopaedic Surgery, NYU Hospital for Joint
Diseases. Michael Elman, M.D., was a Resident from the Department
of Orthopaedic Surgery, Downstate Medical Center, Brooklyn, New
York. Jonathan Gelber, M.D., was a Research Physician, Department
of Orthopaedic Surgery, NYU Hospital for Joint Diseases. David N.
Strauss, M.D., was a Fellow in the Department of Radiology, NYU
Hospital for Joint Diseases. Laith M. Jazrawi, M.D., is Assistant
Professor, New York University School of Medicine, and from the
Divisions of Shoulder and Elbow Surgery and Sports Medicine, Department
of Orthopaedic Surgery, NYU Hospital for Joint Diseases,
NYU Medical Center, New York, New York.
Correspondence: Laith M. Jazrawi M.D., Hospital for Joint Diseases
Department of Orthopaedic Surgery, Suite 1402, 301 East 17th Street,
New York, New York 10003; laith.jazrawi@nyumc.org.
same general indications for surgery. These include point tenderness
of the AC joint, evident abnormal signs with AC joint
scintigraphy andAC radiographs, lack of response to conservative
treatment, and an unwillingness to give up or modify weight
training or manual labor. Distal clavicle resection has provided
good results. Distal clavicle osteolysis is a unique disease most
likely due to an overuse phenomenon.
M
M
any investigators have credited Dupas and colleagues
as first describing, in 1936, osteolysis in
the distal clavicle as a result of trauma.1-8 Since
then, distal clavicular osteolysis (DCO) has been separated
into traumatic and atraumatic pathogeneses. Ehrict was first
credited with reporting that DCO could present without the
“trigger” of acute trauma. In Ehrict’s report, an air-hammer
operator began to suffer from osteolysis.5 Subsequently, the
problem was also diagnosed in a judo player, a deliveryman,
and a handball player.9,10 Atraumatic distal clavicular osteolysis
(ADCO) in weight trainers is thought to arise from a
stress failure syndrome that involves resorption of the distal
clavicle. In 1982, Cahill3 described the first series of male
weight trainers who developed ADCO. The association of
weightlifting and ADCO, as revealed in Cahill’s report, is
especially important considering how routine a component
weights are to the male athlete’s training. Cahill looked at 46
males, none of whom had a history of acute injury to the AC
joint area; 45 of them lifted weights, usually at least three times
a week, with emphasis on the upper extremities. The average
age was 23.3 years.3 Since then, there have been more than
100 cases reported in male weight trainers. In 2001, Sopov
and coworkers published a case report also involving a 20year-
old male. In this case, the upper extremity stress came
from several months of intensive training and lifting, including
carrying a heavy machine gun during soldier/parachutist training.
8 Like Cahill’s patients, there was no history of accidental
trauma.As more females are participating in competitive and
Schwarzkopf R, Ishak C, Elman M, Gelber J, Strauss DN, Jazrawi LM. Distal clavicular osteolysis: a review of the literature. Bull NYU Hosp Jt Dis.
2008;66(2):94-101
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
recreational weight training,ADCO has been reported recently
in a female bodybuilder.6
Acromioclavicular Joint Anatomy
The acromioclavicular joint (AC) is a diarthrodial joint,
stabilized by the coracoclavicular ligaments (conoid and
trapezoid), the superior and inferiorAC ligaments, and theAC
capsule (Fig. 1).A fibrocartilaginous meniscal disc is present
between the convex distal clavicle and the flat acromion. The
coracoclavicular ligaments provide vertical stability to theAC
joint, while theAC ligaments confer horizontal stability. Urist
demonstrated the variability of the AC joint’s orientation.11
Pathogenesis
The pathogenesis of DCO has often been debated. The first etiology
proposed involved a connection between microfractures
of the subchondral bone and subsequent attempts at repair,
which is consistent with repetitive microtrauma. Hyperextension
of the shoulder during bench press or chest flies exercises
(i.e., dropping the elbows below or behind the plane of the
body during the eccentric phase of the press) places excessive
traction on the AC joints and may contribute to ADCO
pathogenesis. Cahill found microfractures in the subchondral
bone in 50% of the surgical specimens in his series and proposed
that repetitive microtrauma caused subchondral stress
fractures and remodeling.2,3 Furthermore, intense osteoblastic
activity of the subchondral bone was discovered in all of the
surgical specimens of osteolytic patients. This appeared to be
predominantly an active repair process. The articular cartilage
of the lateral end of the clavicle exhibited fissuring, degeneration,
and areas of complete absence. This is in contrast
to the tissue of asymptomatic shoulders belonging to 20-to
30-year-old males, in which osteoblastic activity, although
possibly present, is not predominant.3 Brunet described synovial
invasion of the subchondral bone as a possible cause of
osteolysis,2 and MRI findings have been reported to be similar
to synovial proliferation. In one of the few case reports of
DCO occurring in a female patient, Matthews and associates.
pointed out that microscopic examination of a distal clavicle
Figure 1 Normal shoulder on plain radiographs and
MRI. Top,AP views in slightly different obliquities of
two different patients, demonstrating a normal, smooth
contour (arrows) to the clavicular articular surface.
Bottom right, coronal proton density. Bottom left, axial
proton density (A, acromion; C, clavicle).
resection specimen revealed subchondral microcysts, disruption
of the articular cartilage, and metaplastic bone formation
with increased osteoclastic activity,6 again consistent with a
repetitive stress phenomenon. Of all the proposed etiologies,
Cahill’s is the most accepted.
Pathology
Examination of resected sections may reveal fragments of
weakly mineralized trabecular bone proximally, dense scar
tissue distally, and a thin, unorganized hyperplastic fibrocartilaginous
layer. The tissue is often morphologically villous
and hypertrophic, with occasional multinuclear giant cells.
Both active and inactive resorptive surfaces can be observed.
Occasionally, active osteoblastic surfaces are seen with
abnormally large osteoid seams. Where the bone has been
resorbed, hypervascular connective tissue will be laid down.
Overall, the specimens will consistently demonstrate articular
degeneration, chronic inflammation, fibrosis, loss of trabecular
structure, and osteoblastic activity. In addition, studies have
shown contrasting evidence, demonstrating the presence of
synovial hypertrophy and invasion of the underlying bone,
resulting in a synovial pathogenesis.2,3,7 Proponents for a
synovial pathogenesis have shown evidence of hypertrophic
synovial tissue migrating across the cartilaginous surface,
leaving chronic degeneration of the joint. Finally, it has been
suggested that a direct communication between the lesion and
the AC joint is a distinguishing pathological feature.2,12
Symptoms
Symptoms usually begin with an insidious aching pain in
the AC region that is exacerbated by weight training (e.g.,
bench presses, push-ups, dips on the parallel bars,3 overhead
activities, and horizontal adduction). The power clean exercise,
which demands controlled use of the elbows, back, and
shoulders to heist a bar, can precipitate the pain as well, as it
puts significant stress on the AC joint.13 In certain cases, as
symptoms progress, any throwing motion may cause pain.
The athlete’s muscle tone can remain developed. In addition,
there is no sign of subluxation.3 Occasionally, the pain may
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
Figure 2 ScapularY-lateral (left) andAP (right) views
of the right acromioclavicular joint, demonstrating
subtle erosions (arrows) along the clavicular side of
the AC joint.
radiate to the surrounding deltoid or trapezium and is relieved
by prolonged rest. Frequently, patients report difficulty
sleeping on the affected side. Haupt has referred to ADCO
as “weightlifter’s shoulder.”13 In his experience, the pain and
discomfort is often more severe the night after a weightlifting
program. The history of these cases never includes a major
injury to the AC joint.
Physical Examination
Patients have point tenderness over the affected AC joint and
pain with a cross-body adduction maneuver.AC joint stability
should be assessed by grasping the distal clavicle between
the thumb and forefinger and stressing the clavicle in an anteroposterior
and superoinferior direction, while stabilizing
the acromion with the other hand.14 Patients generally have
full range of motion (ROM) of the glenohumeral joint. An
AC joint injection can be both a diagnostic and a treatment
modality in the management of DCO.
Differential Diagnosis
Although DCO may seem like an easy and quick diagnosis,
one must rule out other possibilities. Some of the more important
etiologies that should be excluded from the differential
include hyperparathyroidism, gout, scleroderma, rheumatoid
arthritis, multiple myeloma, infection, and massive essential
osteolysis (Gorham’s disease).6 Cervical spine and neurovascular
evaluations are also important to rule out as potential
sources of referred pain.
Imaging
Radiographs of both AC joints, using a 35° cephalad technique,
will reveal radiographic changes of the AC joint although
some will be more subtle than others. Zanca described
anAP view with the beam tilted 15° cephalad to better visualize
theAC joint without overlapping the spine of the scapula.15
The early radiographic signs are seen months or years after
weight training has begun. In patients who have had severe
symptoms, a 10° to 15° cephalic tilt AP plain radiograph
view of the shoulder may reveal loss of subchondral bone in
the distal clavicle, microcystic changes in the subchondral
area, and widening of the AC joint (Fig. 2).3 The acromion in
ADCO is spared of lytic changes. The presence of panarticular
disease should lead to the consideration of other diagnoses
(e.g.,AC arthritis). However, previous investigators have noted
that radiographic appearance of the distal clavicle may vary
considerably with the age and activity of the individual, as
well as with the radiographic technique applied.8
Early in the course of symptoms, Tc-99 scintigraphy with
marked uptake in the distal clavicle may help to confirm AC
joint involvement before changes become apparent on plain
radiographs; at times, there is also increased activity in the
adjacent acromion.3 Some critics have pointed out that the
metaphyseal end of all long bones demonstrates an increase
in the uptake on scintiscan, and the clavicle is no exception.
A further increase in the uptake of that area can represent a
simple increase in bone turnover, due to the stress applied by
young individuals, and is a normal phenomenon.16 It may be
related to an increased blood flow and blood pooling. However,
active male athletes do not normally have significantly
increased activity in the clavicle or metaphyseal ends. In
Cahill’s study, 31 patients of the same age group and activity
level as a DCO group who had other causes of shoulder symptoms
did not demonstrate increased scintigraphic activity.3
Magnetic resonance imaging (MRI), which often
focuses on the rotator cuff muscles and glenoid labrum,
may overlook clavicular osteolysis if a suggestive history
or radiograph is unavailable.4 MR imaging demonstrates
increased signal intensity associated with T2-weighted
images, most notably on the fluid-sensitive STIR and fat-
Figure 3 Early MRI changes in DCO. Axial T2 (top left), axial T1
(bottom left), coronal proton density (right) demonstrating subtle
erosions (arrows) and mild adjacent subchondral marrow edema
(chevron).
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
suppressed spin echo on the T2-weighted sequences (Fig.
3).4 Bone marrow edema may be found in all of the cases,
but never solely in the acromion. Bone marrow edema in
the distal clavicle is the most common manifestation of
this disease.4,17 Edema in this area has a high correlation
with the presence of symptoms. Overall, posttraumatic and
stress-induced osteolysis of the distal clavicle have similar
appearances, the most common being the increased T2
signal intensity in the distal clavicle (Fig. 4). Additional
findings of osseous fragments, osseous irregularity, and
fluid in the AC joint have been deemed to be common, but
not universal.4 Perhaps the simplest radiographic findings
are distal clavicle osteopenia early in the disease and tapering
of the distal clavicle late in the disease.6
CT Guided Injection
Some physicians have found it helpful to use corticosteroid
injections as both a therapeutic and a diagnostic tool. If
the patient is suffering from AC joint pain, an injection
may temporarily relieve the pain. Intra-articular corticosteroids
can be considered for short-term symptom relief;
however, they provide little long-term relief. The greatest
benefit may be that a positive temporary relief of pain can
be seen as a diagnostic tool for confirming that the pain is
indeed localized in the AC joint. Worcester and Green noted
100% pain relief for patients who underwent surgery and
who experienced temporary relief of symptoms with two
or more injections.18 In his case report, Sopov8 presented
evidence in support of a CT-guided injection as treatment
for DCO. After 3 months of conservative therapy and oral
NSAIDs, Sopov’s soldier did not improve. Local corticosteroids
were deemed to be an appropriate response to
patients that do not respond to conservative treatment.8,16
Under CT guidance, 5 m/L of anesthetic (0.5% Marcaine®)
and 40 mg of corticosteroid were injected into the AC
joint. This procedure resulted in a relief of symptoms for
6 months. It is important to note that, besides possibly
relieving symptoms, a CT-guided injection allows location
of the best point on the skin, appropriate depth and needle
inclination, and correct positioning of the needle tip.8
Nonsurgical Therapy
Avoidance of provocative maneuvers, modification of
weight training techniques, ice massage, and nonsteroidal
Figure 4 Axial (left) and sagittal (right) fluid-
weighted, fat-suppressed images, demonstrating
more advanced DCO with a greater degree of marrow
edema and more pronounced distal clavicular
erosions. Note the prominence of musculature and
relative paucity of fat in this avid weightlifter.
antiinflammatory drugs (NSAID) constitute the basis of
initial treatment. Haupt has suggested several modifications
to the weightlifting routine, as it is often difficult to remove
or alter the young athlete’s weight-training program.13
Since most athletes find it difficult to eliminate the bench
press from their routine, most of the specific modifications
of weight training techniques involve narrowing the hand
spacing on the barbell (less than 1.5 times the bi-acromial
width) and controlling the descent phase of the bench
press to end approximately 4 to 6 cm above the anterior
chest.19 Some patients may find that placing towels on
their chest as spacers may reinforce this restriction. The
narrower handgrip allows the athlete to make adjustments
to the component angles of the bench press by maintaining
shoulder abduction at less than 45° and shoulder extension
at less than 15°. This then decreases the compressive force
on the distal clavicle.19
The power clean, although a rather full-body functional
exercise, does place significant stress on the AC joint during
the “racking” phase. In this part of the exercise, the
shoulders are shrugged, the elbows flexed, and then the
shoulders are abducted to bring the bar up into a “racked”
position. If the athlete is suffering from an AC joint injury,
the power clean should be modified to allow only the pulling
portion of the lift without racking the bar—an exercise
termed a “power clean high pull” or “power pull.” The
key to this motion is that the athlete still gains a lower
extremity benefit but avoids additional AC trauma that can
be associated with a mistimed lift.19 The preferred way to
perform the exercise is to adjust the exercise machine or
starting position so that the elbows are even with or above
the frontal plane when beginning the lift and during repetitions
(Honing technique). Haupt notes that his practice
routine promotes a program in which the bench press, dips,
and push-ups are eliminated. Alternative recommendations
are the cable crossover, dumbbell decline press, and
incline press with straight bar.13 All pressing motions are
performed with a narrow grip, no greater than 1.5 times
the bi-acromial width. Conservative physicians also stress
the use of NSAID and ice massage of the AC joint after all
workouts.13 Since many of these athletes will tend to work
through pain, more conservative physicians may allow
them to continue to workout. In a sense, continued physical
activity and pathogenesis will result in a “self-surgery”;
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
that is, the clavicle will be resected on its own. With such
high association of DCO with power lifting, especially the
bench press, one may be quick to avoid some of the aforementioned
exercises. However, it is important to note that
a questionnaire study of elite power lifters in 1995 and in
2000 showed that no particular movement used in weekly
training, including the bench press, led to an increased risk
of shoulder injuries.20 A patient whose condition does not
respond to conservative management or who is unwilling to
alter his or her exercise training and performance regimen
require surgery.
Surgery
Much of the literature supports the same general indications
for surgery. These include point tenderness of the AC joint,
evident abnormal signs with AC joint scintigraphy and AC
radiographs, lack of response to conservative treatment, and an
unwillingness to give up or modify weight training or manual
labor.2,3,6 The most common type of surgery for DCO has been
a distal clavicle resection. Both open and arthroscopic distal
clavicle resection have been successful in alleviating pain
and returning patients to previous activity levels.3,21 Once
the indications are supportive of surgery, the decision must
be made as to how much of the clavicle should be resected
and whether to perform an open or arthroscopic procedure.
While Cahill reported excellent results with an open approach
resecting 1 to 2 cm of distal clavicle, a recent study reported
that arthroscopic resection of only 4 mm was effective.22
The distal clavicle should be resected enough to prevent AC
impingement through a full range of shoulder motion. The
arthroscopic technique is technically more demanding, but
it is more cosmetically appealing, and patients can perform
active range of motion within the first week to prevent loss of
shoulder motion. Cahill reports that 37 of 40 patients who had
surgical excisions returned to weight training or competitive
weight lifting, or both.3
Open Procedure
The rationale of the open procedure is that the pathological
articular surfaces can be resected under direct vision in order
to create a wide enough margin to prevent further acromion
abutment on the clavicle. Two skin incisions can be used,
the strap and the horizontal.13 The junction of the deltoid
and trapezius fascia must be split to provide proper exposure
of the AC joint. Classically, the amount of distal clavicle
and acromion resected combined has been 1 to 2 cm; this is
most commonly referred to as the Mumford procedure.After
excision of the clavicle, the inferior AC joint capsule can be
incorporated into the repair of the deltoid and trapezius fascia
in order to eliminate any potential dead space. Flatow and
colleagues support the transferring of the coracoacromial ligament
to cover the outer end of the clavicle in order to provide
additional stability to the weightlifter.23 Cahill noted that the
AC joint might play a role in impingement syndrome. Further,
surgical removal of the lateral end of the clavicle may aid in
decompressing the coracoacromial arch.3 Osteolysis may be
differentiated from impingement syndrome by both history
and examination.
The majority of follow-up studies have reported positive
results when considering pain as a major indicator of success.
In 1994, Slawski and Cahill published a paper analyzing the
efficacy of an open distal clavicle resection on patients suffering
from distal clavicle osteolysis.7 At the time, it was the
first known series evaluating the results of this procedure for
DCO and using a standard shoulder rating scale, the UCLA
Shoulder Rating Scale. The study group consisted of 12 active
weight lifters and two manual laborers.All patients returned to
full sports activity and employment by an average of 9 weeks
postoperatively (range, 5 to 12 weeks). In addition, all patients
reported returning to a level of competition or productivity
as good as or better than when they had been symptomatic.
Although some minimal residual pain was reported, all were
satisfied with the results and no postoperative complications
were reported. The UCLA Shoulder Rating Scale was then
used to evaluate follow-up pain and function. The average
score was 33.5 (range, 29 to 35). There were eight excellent
and nine good results, with no fair or poor scores. There were
no discernible measured losses of motion or strength in the
operated shoulders. None of the patients were weaker on the
operated side, compared to the nonoperated side.7 Worcester
and Green noted pain relief within 4 to 8 weeks in most patients.
Good to excellent results were noted in 53% to 100%
of patients in follow-ups of 13 months to 9 years.18
It is important to note that Cook and Tibone attempted to
quantify weakness objectively in 23 athletes who reported
painless full range of motion at an average of 3.7 years postoperatively.
Their goal was to measure true weakness as opposed
to pain-induced weakness. The findings included radiographic
evidence of increased horizontal translation, decreased flexion
and extension power when tested on a weight machine at 60°
per second, and diminished strength in the bench press.24
Although, the open procedure has been shown to produce
good to excellent results clinically, the extensive tissue damage
required to gain access to the AC joint may involve a hospital
stay, requires more rehabilitation, and has been linked to
resulting muscle weakness.24-27 Some open procedures have
been considered failures due to limited range of motion. The
abutment of the distal clavicle stump on the acromion with
arm motion can be due to a result of disruption of the AC
ligaments from an open resection.23
Arthroscopic Technique
The Arthroscopic technique, on the other hand, involves less
tissue dissection, less rehabilitation time (patients can begin
active and passive range of motion on day 1 postoperatively),
can be performed on an outpatient basis, and avoids postoperative
muscle weakness.28 Pain relief was achieved an average
of 3.4 months earlier in arthroscopic patients who received a
superior approach.23 Additionally, less bone can be removed
than in the open procedure.23,26 Evidence has shown that 0.5
to 1.0 cm arthroscopic resections are comparable to the 1.5 to
2.0 cm resections performed during an open procedure.26,29
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
Subacromial (Indirect) Approach
The subacromial approach, first described by Ellman and
Esch, preserves the superior AC joint ligaments and provides
less chance for postoperative instability (Fig. 5). The technique
uses anterior instrumental, posterior scope, and lateral inflow
portals. A shaver is used to debride initially any obscuring
bursa. Electrocautery is used to clearly demarcate the distal
clavicle and minimize bleeding. Great care should be used not
to disrupt the supporting ligaments and capsule. Once good
visualization is obtained, a burr (usually 5 to 6 mm) is used
through the anterior portal to clear any remaining osteophytes
and to resect the distal clavicle from anterior to posterior.
Modifications of this technique include burring from both
the posterior and the lateral portals, as well as visualization
through the three standard portals. Bone depth can be gauged
using the known diameter of a burr; however, Tolin and Snyder30
recommend the routine use of two needles to demarcate
the orientation of the joint, as well as to gauge the amount
of bone resected, by measuring the distance between the two
needles on the skin.Although some investigators recommend
resecting a small portion of the medial acromion, most find
it unnecessary. To aid in resection of the superior portion of
the distal clavicle, manual pressure can be applied to bring
the clavicle into the subacromial space. It has been suggested
that failure of this technique is not due to the amount of bone
removed, but rather the result of uneven resection or disruption
of theAC ligaments. This would lead to translation of the
clavicle, resulting in an abutment on the acromion and cause
recurring symptoms.21,31-34 This problem often happens after
aggressive arthroscopic resection when care is not taken to
preserve the stabilizing ligamentous envelope. Morrison and
colleagues recommend beveling the posterior edge of the
distal clavicle if this instability is recognized intraoperatively
to avoid the resultant painful impingement.35
Kay and coworkers studied a lateral decubitus position
in conjunction with subacromial decompression and distal
clavicle resection via a bursal approach.36 The lateral position
allows the patient’s arm to be suspended by a boom loaded
with weights. If the lateral position is used, an inflatable “bean
bag” can be positioned to support the patient. An axillary roll
will protect the uninvolved arm, and pillows placed between
the patient’s knees and under the bottom leg will protect the
peroneal nerve.All 10 patients studied obtained a satisfactory
outcome. The five recreational athletes, including the weight-
lifters, returned to their sports at or above their preinjury level.
All patients returned to their preinjury occupation, with half
missing work only on the day of surgery. One patient was at
a hockey camp participating in drills 5 days after the surgery.
Postoperatively, the patients’ functionality was a 9.6 on the
UCLA shoulder scale (range, 8 to 10), and their pain averaged
a 9.4 (range, 8 to 10). Seven of the 10 patients were pain-free
by 12 weeks postoperatively.36
It has often been believed that the bursal approach may not
allow easy access of the clavicle in a tight joint with medial
inclination, especially in osteoarthritic joints, even with direct
superior pressure on the clavicle.37 An open incision has been
proposed for these cases by surgeons favoring the bursal approach.
Tolin and Snyder believed they overcame this problem
by using a lateral position with 10 to 15 pounds traction on a
70° abducted arm.30
First described by Lanny Johnson and later championed by
Flatow and associates,23 the superior approach offers a direct
approach to theAC joint, avoiding violation of the subacromial
space, in which there may be no pathology.
Superior (Direct) Approach
While some investigators recommend routing arthroscopic
examination of the subacromial space for potential pathology,
others believe that there is no reason to violate the bursa
in isolated AC problems.23 Therefore, their preferred method
for surgically treating DCO is a superior direct approach. A
superior approach also allows resection of the outer end of
the clavicle under direct visualization, without the edema and
bleeding of a bursal approach. Prior to the start of a superior
approach, regional interscalene anesthesia may be used. The
patient can be placed either in a beach chair position38 or the
arm can be suspended by a boom, with less than 50°of abduction
and less than 15° of forward flexion with 10 pounds of
Figure 5 Intraoperative photos of the indirect subacromial approach; posterior-anterior (left) and lateral (right) views of the right AC joint,
centered on the clavicle, with arrows indicating the acromion.
100 Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
weight.14 Two small-bore needles (22 gauge, 1.5 inch) are used
to determine the location and orientation of the joint so as to
allow precise introduction of the instruments. This is critical,
because otherwise variations in joint inclination may be hard
to appreciate.A 4.0 mm 30° arthroscope and necessary instruments
are placed into the AC joint via direct anterosuperior
and posterosuperior portals. A 2.7 mm arthroscope may be
placed initially if the joint space is narrow.23,38 The capsule
and ligaments of the AC joint are subperiosteally elevated
to expose the distal clavicle, allowing direct visualization of
the clavicle. The meniscus and intra-articular soft tissues are
resected with a 5.0 mm motorized full-radius resector.38 An
electrocautery unit may be used to shell out the outer end of
the clavicle in order to preserve the soft tissue containing the
AC ligaments and capsule.23 After this, if the joint space is
large enough, a 6.0 mm burr is introduced. If the space is too
small, more room can be created using smaller burrs first until
the 6.0 mm burr can be accommodated.Approximately 4 to 7
mm of the distal clavicle is removed.38 After resection, the joint
should be carefully examined arthroscopically from both the
anterior and posterior portals to ensure adequate bone removal
and to check for loose fragments. It is essential to probe the
edges to be sure that no overhanging ridges remain.23 Flatow
and associates reported a 91% success rate with the superior
approach,23 while Zawadsky and colleagues determined that
all results of superior arthroscopic distal clavicle resection of
ADCO were either good or excellent.38
Limited (less than 1 to 2 cm) arthroscopic distal clavicular
resection (DCR), specifically in weightlifters, has shown
promising results.22 The surgical approach consists of a
superior arthroscopic approach to the AC joint with two portals.
22,23,28 Standard arthroscopic instrumentation (30° camera
and 4.0 mm arthroscope), an arthroscopic shaver, and a 4 mm
motorized burr should be used. The AC joint is debrided of
material such as meniscal remnants and cartilaginous debris.
The distal 4 mm of the clavicle is resected with the burr, using
the diameter of the burr as a guide. The outer cortical shell of
the distal clavicle is addressed with the burr after elevating
the capsule from the clavicle with electrocautery, sparing the
superiorAC ligament.A rhinoplasty rasp can be used through
the portals to complete the distal clavicle contouring.22
Experienced weightlifters are accustomed to self-directed
training and biofeedback. Follow-ups of limited DCR on
weightlifters have shown that they can resume their training
within the first week postoperatively (average, 3.2 days; range,
1 to 6 days). Preoperative training levels can be reached by
the second week postoperatively (average, 9.1 days; range 7
to 12 days).Very few patients will lose strength in the military
press or the incline press.22
Although distal clavicle resection has been shown to be a
successful procedure, some failures have been reported. One
of the least recognized reasons of failure may be heterotopic
bone formation. Thus, most investigators recommend removal
of all bone and fragments within the joint in order to avoid a
nidus for new bone formation. Berg and Ciullo suggested that
it might be a more common cause of failure of both acromio
plasty and distal clavicle resection.39 They suggested the use of
prophylactic measures with patients considered at risk. They
found their at-risk group to include patients with hypertrophic
AC joint osteoarthritis that either were long-standing smokers
or had other chronic pulmonary diseases. However, since
periosteal bone formation can be a component of pulmonary
osteoarthropathy, the results could have been attributed to a
low partial pressure of oxygen and tissue hypoxia in their patients.
This is reinforced by the fact that 60% of their patients
had an incidence of chronic pulmonary disease, which was
significantly higher than the United States average.39
Resection of the distal clavicle and disruption of the AC
articulation creates the potential for another complication—
abnormal postoperative motion. Blazar and colleagues studied
17 isolated distal clavicle patients (open and arthroscopic)
and discovered that the average anterior plus posterior
translation was 8.7 mm (range, 3 to 21 mm), which was significantly
greater than the contralateral shoulders (mean, 3.2
mm; range, 1 to 6 mm). The amount of pain determined by a
questionnaire, correlated with the amount of translation and
showed that excessive anteroposterior instability of the distal
clavicle can cause postoperative pain and lead to poor surgical
outcomes.40 In a cadaveric study, Miller and coworkers
determined that there was no statistically significant difference
in the anteroposterior translation between direct or indirect
arthroscopic distal clavicle resections.41 Other complications
include underlying muscle injury, excessive bleeding, lateral
clavicle fracture, and infection.
Conclusions
In summary, distal clavicle osteolysis is a unique disease most
likely due to an overuse phenomenon.When activity modification
and conservative treatment fails to provide relief in an active
patient, distal clavicle resection has provided good results.
In isolated DCO, there is scarcely any indication for an open
procedure, while the superior and subacromial approaches
have their pros and cons. The subacromial approach offers
certain advantages, including: 1. assessing for other pathology
or working through established portals if other pathology is
already being addressed, 2. less injury to the capsule, and 3.
no need for smaller instruments. Disadvantages include: 1.
violating an area with potentially no pathology, 2. more portals,
and 3. more bleeding and fluid extravasation. The merits
of a direct approach should not be discounted.
Disclosure Statement
None of the authors have a financial or proprietary interest
in the subject matter or materials discussed, including, but
not limited to, employment, consultancies, stock ownership,
honoraria, and paid expert testimony.
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Clancey GJ. Osteolysis in the distal part of the clavicle in male
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Patten RM. Atraumatic osteolysis of the distal clavicle: MR
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Flatow EL, Duralde XA, Nicholson GP, et al. Arthroscopic
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AugeWK,2nd,FischerRA.Arthroscopicdistalclavicleresection
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Cook FF, Tibone JE. The Mumford procedure in athletes. An
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Joint Surg Am. 1986 Mar;68(3):434-40.
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Weaver JK, Dunn HK. Treatment of acromioclavicular injuries,
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Surg Am. 1972 Sep;54(6):1187-94.
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Morrision DS, Frogameni AD, Woodworth P. Non-operative
treatment of subacromial impingement syndrome. J Bone Joint
Surg AM. 1997 May;79(5):732-7.
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Kay SP, Ellman H, Harris E. Arthroscopic distal clavicle excision.
Technique and early results. Clin Orthop Relat Res. 1994
Apr;(301):181-4.
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Henry MH, Liu SH, Loffredo AJ. Arthroscopic management
of the acromioclavicular joint disorder. A review. Clin Orthop
Relat Res. 1995 Jul(316):276-83.
38.
Zawadsky M, Marra G, Wiater JM, et al. Osteolysis of the
distal clavicle: long-term results of arthroscopic resection.
Arthroscopy. 2000 Sep;16(6):600-5.
39.
Berg EE, Ciullo JV. Heterotopic ossification after acromioplasty
and distal clavicle resection. J Shoulder Elbow Surg. 1995
May-Jun;4(3):188-93.
40.
BlazarPE,IannottiJP,WilliamsGR.Anteroposteriorinstability
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41.
Miller CA, Ong BC, Jazrawi LM, et al. Assessment of clavicular
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distal clavicle osteolysis
Everyone with this, please read this article that I attached. This article is a review of all the research on this topic and is very interesting for anyone suffering from this condition as I have over the last 10 years. One thing I find most interesting is that they suggest that working through the pain will cause the clavicle to wear away enough that it stops rubbing, a self surgery and cure, which is very interesting and I would love to hear of anyone who has actually done that. I myself have avoided the surgery by stopping bench/incline/decline press and dips. Sorry its in txt format, the pdf was too large.
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
Distal Clavicular Osteolysis
A Review of the Literature
Ran Schwarzkopf, M.D., M.Sc., Charbel Ishak, M.D., Michael Elman, M.D.,
Jonathan Gelber, M.D., David N. Strauss, M.D., and Laith M. Jazrawi, M.D.
Abstract
Acute distal clavicular osteolysis was first described in 1936.
Since then, distal clavicular osteolysis (DCO) has been separated
into traumatic and atraumatic pathogeneses. In 1982 the
first series of male weight trainers who developed ADCO was
reported. The association of weightlifting and ADCO is especially
important considering how routine a component weights
are to the male athlete’s training.The pathogenesis of DCO has
oftenbeendebated.The mostwidelyacceptedetiologyinvolvesa
connection between microfracturesof thesubchondral bone and
subsequent attempts at repair, which is consistent with repetitive
microtrauma. Symptoms usually begin with an insidious aching
pain in theAC region that is exacerbated by weight training. On
examination,patients havepointtenderness overtheaffectedAC
joint and pain with a cross-body adduction maneuver.Although
DCO may seem like an easy and quick diagnosis, one must rule
out other possibilities. Avoidance of provocative maneuvers,
modification of weight training techniques, ice massage, and
nonsteroidal anti-inflammatory drugs (NSAID) constitute the
basis of initial treatment. Much of the literature supports the
Ran Schwarzkopf, M.D., M.Sc., is a Resident in the Department
of Orthopaedic Surgery, NYU Hospital for Joint Diseases. Charbel
Ishak, M.D., is a Research Physician, Musculoskeletal Research
Center, Department of Orthopaedic Surgery, NYU Hospital for Joint
Diseases. Michael Elman, M.D., was a Resident from the Department
of Orthopaedic Surgery, Downstate Medical Center, Brooklyn, New
York. Jonathan Gelber, M.D., was a Research Physician, Department
of Orthopaedic Surgery, NYU Hospital for Joint Diseases. David N.
Strauss, M.D., was a Fellow in the Department of Radiology, NYU
Hospital for Joint Diseases. Laith M. Jazrawi, M.D., is Assistant
Professor, New York University School of Medicine, and from the
Divisions of Shoulder and Elbow Surgery and Sports Medicine, Department
of Orthopaedic Surgery, NYU Hospital for Joint Diseases,
NYU Medical Center, New York, New York.
Correspondence: Laith M. Jazrawi M.D., Hospital for Joint Diseases
Department of Orthopaedic Surgery, Suite 1402, 301 East 17th Street,
New York, New York 10003; laith.jazrawi@nyumc.org.
same general indications for surgery. These include point tenderness
of the AC joint, evident abnormal signs with AC joint
scintigraphy andAC radiographs, lack of response to conservative
treatment, and an unwillingness to give up or modify weight
training or manual labor. Distal clavicle resection has provided
good results. Distal clavicle osteolysis is a unique disease most
likely due to an overuse phenomenon.
M
M
any investigators have credited Dupas and colleagues
as first describing, in 1936, osteolysis in
the distal clavicle as a result of trauma.1-8 Since
then, distal clavicular osteolysis (DCO) has been separated
into traumatic and atraumatic pathogeneses. Ehrict was first
credited with reporting that DCO could present without the
“trigger” of acute trauma. In Ehrict’s report, an air-hammer
operator began to suffer from osteolysis.5 Subsequently, the
problem was also diagnosed in a judo player, a deliveryman,
and a handball player.9,10 Atraumatic distal clavicular osteolysis
(ADCO) in weight trainers is thought to arise from a
stress failure syndrome that involves resorption of the distal
clavicle. In 1982, Cahill3 described the first series of male
weight trainers who developed ADCO. The association of
weightlifting and ADCO, as revealed in Cahill’s report, is
especially important considering how routine a component
weights are to the male athlete’s training. Cahill looked at 46
males, none of whom had a history of acute injury to the AC
joint area; 45 of them lifted weights, usually at least three times
a week, with emphasis on the upper extremities. The average
age was 23.3 years.3 Since then, there have been more than
100 cases reported in male weight trainers. In 2001, Sopov
and coworkers published a case report also involving a 20year-
old male. In this case, the upper extremity stress came
from several months of intensive training and lifting, including
carrying a heavy machine gun during soldier/parachutist training.
8 Like Cahill’s patients, there was no history of accidental
trauma.As more females are participating in competitive and
Schwarzkopf R, Ishak C, Elman M, Gelber J, Strauss DN, Jazrawi LM. Distal clavicular osteolysis: a review of the literature. Bull NYU Hosp Jt Dis.
2008;66(2):94-101
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
recreational weight training,ADCO has been reported recently
in a female bodybuilder.6
Acromioclavicular Joint Anatomy
The acromioclavicular joint (AC) is a diarthrodial joint,
stabilized by the coracoclavicular ligaments (conoid and
trapezoid), the superior and inferiorAC ligaments, and theAC
capsule (Fig. 1).A fibrocartilaginous meniscal disc is present
between the convex distal clavicle and the flat acromion. The
coracoclavicular ligaments provide vertical stability to theAC
joint, while theAC ligaments confer horizontal stability. Urist
demonstrated the variability of the AC joint’s orientation.11
Pathogenesis
The pathogenesis of DCO has often been debated. The first etiology
proposed involved a connection between microfractures
of the subchondral bone and subsequent attempts at repair,
which is consistent with repetitive microtrauma. Hyperextension
of the shoulder during bench press or chest flies exercises
(i.e., dropping the elbows below or behind the plane of the
body during the eccentric phase of the press) places excessive
traction on the AC joints and may contribute to ADCO
pathogenesis. Cahill found microfractures in the subchondral
bone in 50% of the surgical specimens in his series and proposed
that repetitive microtrauma caused subchondral stress
fractures and remodeling.2,3 Furthermore, intense osteoblastic
activity of the subchondral bone was discovered in all of the
surgical specimens of osteolytic patients. This appeared to be
predominantly an active repair process. The articular cartilage
of the lateral end of the clavicle exhibited fissuring, degeneration,
and areas of complete absence. This is in contrast
to the tissue of asymptomatic shoulders belonging to 20-to
30-year-old males, in which osteoblastic activity, although
possibly present, is not predominant.3 Brunet described synovial
invasion of the subchondral bone as a possible cause of
osteolysis,2 and MRI findings have been reported to be similar
to synovial proliferation. In one of the few case reports of
DCO occurring in a female patient, Matthews and associates.
pointed out that microscopic examination of a distal clavicle
Figure 1 Normal shoulder on plain radiographs and
MRI. Top,AP views in slightly different obliquities of
two different patients, demonstrating a normal, smooth
contour (arrows) to the clavicular articular surface.
Bottom right, coronal proton density. Bottom left, axial
proton density (A, acromion; C, clavicle).
resection specimen revealed subchondral microcysts, disruption
of the articular cartilage, and metaplastic bone formation
with increased osteoclastic activity,6 again consistent with a
repetitive stress phenomenon. Of all the proposed etiologies,
Cahill’s is the most accepted.
Pathology
Examination of resected sections may reveal fragments of
weakly mineralized trabecular bone proximally, dense scar
tissue distally, and a thin, unorganized hyperplastic fibrocartilaginous
layer. The tissue is often morphologically villous
and hypertrophic, with occasional multinuclear giant cells.
Both active and inactive resorptive surfaces can be observed.
Occasionally, active osteoblastic surfaces are seen with
abnormally large osteoid seams. Where the bone has been
resorbed, hypervascular connective tissue will be laid down.
Overall, the specimens will consistently demonstrate articular
degeneration, chronic inflammation, fibrosis, loss of trabecular
structure, and osteoblastic activity. In addition, studies have
shown contrasting evidence, demonstrating the presence of
synovial hypertrophy and invasion of the underlying bone,
resulting in a synovial pathogenesis.2,3,7 Proponents for a
synovial pathogenesis have shown evidence of hypertrophic
synovial tissue migrating across the cartilaginous surface,
leaving chronic degeneration of the joint. Finally, it has been
suggested that a direct communication between the lesion and
the AC joint is a distinguishing pathological feature.2,12
Symptoms
Symptoms usually begin with an insidious aching pain in
the AC region that is exacerbated by weight training (e.g.,
bench presses, push-ups, dips on the parallel bars,3 overhead
activities, and horizontal adduction). The power clean exercise,
which demands controlled use of the elbows, back, and
shoulders to heist a bar, can precipitate the pain as well, as it
puts significant stress on the AC joint.13 In certain cases, as
symptoms progress, any throwing motion may cause pain.
The athlete’s muscle tone can remain developed. In addition,
there is no sign of subluxation.3 Occasionally, the pain may
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
Figure 2 ScapularY-lateral (left) andAP (right) views
of the right acromioclavicular joint, demonstrating
subtle erosions (arrows) along the clavicular side of
the AC joint.
radiate to the surrounding deltoid or trapezium and is relieved
by prolonged rest. Frequently, patients report difficulty
sleeping on the affected side. Haupt has referred to ADCO
as “weightlifter’s shoulder.”13 In his experience, the pain and
discomfort is often more severe the night after a weightlifting
program. The history of these cases never includes a major
injury to the AC joint.
Physical Examination
Patients have point tenderness over the affected AC joint and
pain with a cross-body adduction maneuver.AC joint stability
should be assessed by grasping the distal clavicle between
the thumb and forefinger and stressing the clavicle in an anteroposterior
and superoinferior direction, while stabilizing
the acromion with the other hand.14 Patients generally have
full range of motion (ROM) of the glenohumeral joint. An
AC joint injection can be both a diagnostic and a treatment
modality in the management of DCO.
Differential Diagnosis
Although DCO may seem like an easy and quick diagnosis,
one must rule out other possibilities. Some of the more important
etiologies that should be excluded from the differential
include hyperparathyroidism, gout, scleroderma, rheumatoid
arthritis, multiple myeloma, infection, and massive essential
osteolysis (Gorham’s disease).6 Cervical spine and neurovascular
evaluations are also important to rule out as potential
sources of referred pain.
Imaging
Radiographs of both AC joints, using a 35° cephalad technique,
will reveal radiographic changes of the AC joint although
some will be more subtle than others. Zanca described
anAP view with the beam tilted 15° cephalad to better visualize
theAC joint without overlapping the spine of the scapula.15
The early radiographic signs are seen months or years after
weight training has begun. In patients who have had severe
symptoms, a 10° to 15° cephalic tilt AP plain radiograph
view of the shoulder may reveal loss of subchondral bone in
the distal clavicle, microcystic changes in the subchondral
area, and widening of the AC joint (Fig. 2).3 The acromion in
ADCO is spared of lytic changes. The presence of panarticular
disease should lead to the consideration of other diagnoses
(e.g.,AC arthritis). However, previous investigators have noted
that radiographic appearance of the distal clavicle may vary
considerably with the age and activity of the individual, as
well as with the radiographic technique applied.8
Early in the course of symptoms, Tc-99 scintigraphy with
marked uptake in the distal clavicle may help to confirm AC
joint involvement before changes become apparent on plain
radiographs; at times, there is also increased activity in the
adjacent acromion.3 Some critics have pointed out that the
metaphyseal end of all long bones demonstrates an increase
in the uptake on scintiscan, and the clavicle is no exception.
A further increase in the uptake of that area can represent a
simple increase in bone turnover, due to the stress applied by
young individuals, and is a normal phenomenon.16 It may be
related to an increased blood flow and blood pooling. However,
active male athletes do not normally have significantly
increased activity in the clavicle or metaphyseal ends. In
Cahill’s study, 31 patients of the same age group and activity
level as a DCO group who had other causes of shoulder symptoms
did not demonstrate increased scintigraphic activity.3
Magnetic resonance imaging (MRI), which often
focuses on the rotator cuff muscles and glenoid labrum,
may overlook clavicular osteolysis if a suggestive history
or radiograph is unavailable.4 MR imaging demonstrates
increased signal intensity associated with T2-weighted
images, most notably on the fluid-sensitive STIR and fat-
Figure 3 Early MRI changes in DCO. Axial T2 (top left), axial T1
(bottom left), coronal proton density (right) demonstrating subtle
erosions (arrows) and mild adjacent subchondral marrow edema
(chevron).
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
suppressed spin echo on the T2-weighted sequences (Fig.
3).4 Bone marrow edema may be found in all of the cases,
but never solely in the acromion. Bone marrow edema in
the distal clavicle is the most common manifestation of
this disease.4,17 Edema in this area has a high correlation
with the presence of symptoms. Overall, posttraumatic and
stress-induced osteolysis of the distal clavicle have similar
appearances, the most common being the increased T2
signal intensity in the distal clavicle (Fig. 4). Additional
findings of osseous fragments, osseous irregularity, and
fluid in the AC joint have been deemed to be common, but
not universal.4 Perhaps the simplest radiographic findings
are distal clavicle osteopenia early in the disease and tapering
of the distal clavicle late in the disease.6
CT Guided Injection
Some physicians have found it helpful to use corticosteroid
injections as both a therapeutic and a diagnostic tool. If
the patient is suffering from AC joint pain, an injection
may temporarily relieve the pain. Intra-articular corticosteroids
can be considered for short-term symptom relief;
however, they provide little long-term relief. The greatest
benefit may be that a positive temporary relief of pain can
be seen as a diagnostic tool for confirming that the pain is
indeed localized in the AC joint. Worcester and Green noted
100% pain relief for patients who underwent surgery and
who experienced temporary relief of symptoms with two
or more injections.18 In his case report, Sopov8 presented
evidence in support of a CT-guided injection as treatment
for DCO. After 3 months of conservative therapy and oral
NSAIDs, Sopov’s soldier did not improve. Local corticosteroids
were deemed to be an appropriate response to
patients that do not respond to conservative treatment.8,16
Under CT guidance, 5 m/L of anesthetic (0.5% Marcaine®)
and 40 mg of corticosteroid were injected into the AC
joint. This procedure resulted in a relief of symptoms for
6 months. It is important to note that, besides possibly
relieving symptoms, a CT-guided injection allows location
of the best point on the skin, appropriate depth and needle
inclination, and correct positioning of the needle tip.8
Nonsurgical Therapy
Avoidance of provocative maneuvers, modification of
weight training techniques, ice massage, and nonsteroidal
Figure 4 Axial (left) and sagittal (right) fluid-
weighted, fat-suppressed images, demonstrating
more advanced DCO with a greater degree of marrow
edema and more pronounced distal clavicular
erosions. Note the prominence of musculature and
relative paucity of fat in this avid weightlifter.
antiinflammatory drugs (NSAID) constitute the basis of
initial treatment. Haupt has suggested several modifications
to the weightlifting routine, as it is often difficult to remove
or alter the young athlete’s weight-training program.13
Since most athletes find it difficult to eliminate the bench
press from their routine, most of the specific modifications
of weight training techniques involve narrowing the hand
spacing on the barbell (less than 1.5 times the bi-acromial
width) and controlling the descent phase of the bench
press to end approximately 4 to 6 cm above the anterior
chest.19 Some patients may find that placing towels on
their chest as spacers may reinforce this restriction. The
narrower handgrip allows the athlete to make adjustments
to the component angles of the bench press by maintaining
shoulder abduction at less than 45° and shoulder extension
at less than 15°. This then decreases the compressive force
on the distal clavicle.19
The power clean, although a rather full-body functional
exercise, does place significant stress on the AC joint during
the “racking” phase. In this part of the exercise, the
shoulders are shrugged, the elbows flexed, and then the
shoulders are abducted to bring the bar up into a “racked”
position. If the athlete is suffering from an AC joint injury,
the power clean should be modified to allow only the pulling
portion of the lift without racking the bar—an exercise
termed a “power clean high pull” or “power pull.” The
key to this motion is that the athlete still gains a lower
extremity benefit but avoids additional AC trauma that can
be associated with a mistimed lift.19 The preferred way to
perform the exercise is to adjust the exercise machine or
starting position so that the elbows are even with or above
the frontal plane when beginning the lift and during repetitions
(Honing technique). Haupt notes that his practice
routine promotes a program in which the bench press, dips,
and push-ups are eliminated. Alternative recommendations
are the cable crossover, dumbbell decline press, and
incline press with straight bar.13 All pressing motions are
performed with a narrow grip, no greater than 1.5 times
the bi-acromial width. Conservative physicians also stress
the use of NSAID and ice massage of the AC joint after all
workouts.13 Since many of these athletes will tend to work
through pain, more conservative physicians may allow
them to continue to workout. In a sense, continued physical
activity and pathogenesis will result in a “self-surgery”;
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
that is, the clavicle will be resected on its own. With such
high association of DCO with power lifting, especially the
bench press, one may be quick to avoid some of the aforementioned
exercises. However, it is important to note that
a questionnaire study of elite power lifters in 1995 and in
2000 showed that no particular movement used in weekly
training, including the bench press, led to an increased risk
of shoulder injuries.20 A patient whose condition does not
respond to conservative management or who is unwilling to
alter his or her exercise training and performance regimen
require surgery.
Surgery
Much of the literature supports the same general indications
for surgery. These include point tenderness of the AC joint,
evident abnormal signs with AC joint scintigraphy and AC
radiographs, lack of response to conservative treatment, and an
unwillingness to give up or modify weight training or manual
labor.2,3,6 The most common type of surgery for DCO has been
a distal clavicle resection. Both open and arthroscopic distal
clavicle resection have been successful in alleviating pain
and returning patients to previous activity levels.3,21 Once
the indications are supportive of surgery, the decision must
be made as to how much of the clavicle should be resected
and whether to perform an open or arthroscopic procedure.
While Cahill reported excellent results with an open approach
resecting 1 to 2 cm of distal clavicle, a recent study reported
that arthroscopic resection of only 4 mm was effective.22
The distal clavicle should be resected enough to prevent AC
impingement through a full range of shoulder motion. The
arthroscopic technique is technically more demanding, but
it is more cosmetically appealing, and patients can perform
active range of motion within the first week to prevent loss of
shoulder motion. Cahill reports that 37 of 40 patients who had
surgical excisions returned to weight training or competitive
weight lifting, or both.3
Open Procedure
The rationale of the open procedure is that the pathological
articular surfaces can be resected under direct vision in order
to create a wide enough margin to prevent further acromion
abutment on the clavicle. Two skin incisions can be used,
the strap and the horizontal.13 The junction of the deltoid
and trapezius fascia must be split to provide proper exposure
of the AC joint. Classically, the amount of distal clavicle
and acromion resected combined has been 1 to 2 cm; this is
most commonly referred to as the Mumford procedure.After
excision of the clavicle, the inferior AC joint capsule can be
incorporated into the repair of the deltoid and trapezius fascia
in order to eliminate any potential dead space. Flatow and
colleagues support the transferring of the coracoacromial ligament
to cover the outer end of the clavicle in order to provide
additional stability to the weightlifter.23 Cahill noted that the
AC joint might play a role in impingement syndrome. Further,
surgical removal of the lateral end of the clavicle may aid in
decompressing the coracoacromial arch.3 Osteolysis may be
differentiated from impingement syndrome by both history
and examination.
The majority of follow-up studies have reported positive
results when considering pain as a major indicator of success.
In 1994, Slawski and Cahill published a paper analyzing the
efficacy of an open distal clavicle resection on patients suffering
from distal clavicle osteolysis.7 At the time, it was the
first known series evaluating the results of this procedure for
DCO and using a standard shoulder rating scale, the UCLA
Shoulder Rating Scale. The study group consisted of 12 active
weight lifters and two manual laborers.All patients returned to
full sports activity and employment by an average of 9 weeks
postoperatively (range, 5 to 12 weeks). In addition, all patients
reported returning to a level of competition or productivity
as good as or better than when they had been symptomatic.
Although some minimal residual pain was reported, all were
satisfied with the results and no postoperative complications
were reported. The UCLA Shoulder Rating Scale was then
used to evaluate follow-up pain and function. The average
score was 33.5 (range, 29 to 35). There were eight excellent
and nine good results, with no fair or poor scores. There were
no discernible measured losses of motion or strength in the
operated shoulders. None of the patients were weaker on the
operated side, compared to the nonoperated side.7 Worcester
and Green noted pain relief within 4 to 8 weeks in most patients.
Good to excellent results were noted in 53% to 100%
of patients in follow-ups of 13 months to 9 years.18
It is important to note that Cook and Tibone attempted to
quantify weakness objectively in 23 athletes who reported
painless full range of motion at an average of 3.7 years postoperatively.
Their goal was to measure true weakness as opposed
to pain-induced weakness. The findings included radiographic
evidence of increased horizontal translation, decreased flexion
and extension power when tested on a weight machine at 60°
per second, and diminished strength in the bench press.24
Although, the open procedure has been shown to produce
good to excellent results clinically, the extensive tissue damage
required to gain access to the AC joint may involve a hospital
stay, requires more rehabilitation, and has been linked to
resulting muscle weakness.24-27 Some open procedures have
been considered failures due to limited range of motion. The
abutment of the distal clavicle stump on the acromion with
arm motion can be due to a result of disruption of the AC
ligaments from an open resection.23
Arthroscopic Technique
The Arthroscopic technique, on the other hand, involves less
tissue dissection, less rehabilitation time (patients can begin
active and passive range of motion on day 1 postoperatively),
can be performed on an outpatient basis, and avoids postoperative
muscle weakness.28 Pain relief was achieved an average
of 3.4 months earlier in arthroscopic patients who received a
superior approach.23 Additionally, less bone can be removed
than in the open procedure.23,26 Evidence has shown that 0.5
to 1.0 cm arthroscopic resections are comparable to the 1.5 to
2.0 cm resections performed during an open procedure.26,29
Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
Subacromial (Indirect) Approach
The subacromial approach, first described by Ellman and
Esch, preserves the superior AC joint ligaments and provides
less chance for postoperative instability (Fig. 5). The technique
uses anterior instrumental, posterior scope, and lateral inflow
portals. A shaver is used to debride initially any obscuring
bursa. Electrocautery is used to clearly demarcate the distal
clavicle and minimize bleeding. Great care should be used not
to disrupt the supporting ligaments and capsule. Once good
visualization is obtained, a burr (usually 5 to 6 mm) is used
through the anterior portal to clear any remaining osteophytes
and to resect the distal clavicle from anterior to posterior.
Modifications of this technique include burring from both
the posterior and the lateral portals, as well as visualization
through the three standard portals. Bone depth can be gauged
using the known diameter of a burr; however, Tolin and Snyder30
recommend the routine use of two needles to demarcate
the orientation of the joint, as well as to gauge the amount
of bone resected, by measuring the distance between the two
needles on the skin.Although some investigators recommend
resecting a small portion of the medial acromion, most find
it unnecessary. To aid in resection of the superior portion of
the distal clavicle, manual pressure can be applied to bring
the clavicle into the subacromial space. It has been suggested
that failure of this technique is not due to the amount of bone
removed, but rather the result of uneven resection or disruption
of theAC ligaments. This would lead to translation of the
clavicle, resulting in an abutment on the acromion and cause
recurring symptoms.21,31-34 This problem often happens after
aggressive arthroscopic resection when care is not taken to
preserve the stabilizing ligamentous envelope. Morrison and
colleagues recommend beveling the posterior edge of the
distal clavicle if this instability is recognized intraoperatively
to avoid the resultant painful impingement.35
Kay and coworkers studied a lateral decubitus position
in conjunction with subacromial decompression and distal
clavicle resection via a bursal approach.36 The lateral position
allows the patient’s arm to be suspended by a boom loaded
with weights. If the lateral position is used, an inflatable “bean
bag” can be positioned to support the patient. An axillary roll
will protect the uninvolved arm, and pillows placed between
the patient’s knees and under the bottom leg will protect the
peroneal nerve.All 10 patients studied obtained a satisfactory
outcome. The five recreational athletes, including the weight-
lifters, returned to their sports at or above their preinjury level.
All patients returned to their preinjury occupation, with half
missing work only on the day of surgery. One patient was at
a hockey camp participating in drills 5 days after the surgery.
Postoperatively, the patients’ functionality was a 9.6 on the
UCLA shoulder scale (range, 8 to 10), and their pain averaged
a 9.4 (range, 8 to 10). Seven of the 10 patients were pain-free
by 12 weeks postoperatively.36
It has often been believed that the bursal approach may not
allow easy access of the clavicle in a tight joint with medial
inclination, especially in osteoarthritic joints, even with direct
superior pressure on the clavicle.37 An open incision has been
proposed for these cases by surgeons favoring the bursal approach.
Tolin and Snyder believed they overcame this problem
by using a lateral position with 10 to 15 pounds traction on a
70° abducted arm.30
First described by Lanny Johnson and later championed by
Flatow and associates,23 the superior approach offers a direct
approach to theAC joint, avoiding violation of the subacromial
space, in which there may be no pathology.
Superior (Direct) Approach
While some investigators recommend routing arthroscopic
examination of the subacromial space for potential pathology,
others believe that there is no reason to violate the bursa
in isolated AC problems.23 Therefore, their preferred method
for surgically treating DCO is a superior direct approach. A
superior approach also allows resection of the outer end of
the clavicle under direct visualization, without the edema and
bleeding of a bursal approach. Prior to the start of a superior
approach, regional interscalene anesthesia may be used. The
patient can be placed either in a beach chair position38 or the
arm can be suspended by a boom, with less than 50°of abduction
and less than 15° of forward flexion with 10 pounds of
Figure 5 Intraoperative photos of the indirect subacromial approach; posterior-anterior (left) and lateral (right) views of the right AC joint,
centered on the clavicle, with arrows indicating the acromion.
100 Bulletin of the NYU Hospital for Joint Diseases 2008;66(2):94-101
weight.14 Two small-bore needles (22 gauge, 1.5 inch) are used
to determine the location and orientation of the joint so as to
allow precise introduction of the instruments. This is critical,
because otherwise variations in joint inclination may be hard
to appreciate.A 4.0 mm 30° arthroscope and necessary instruments
are placed into the AC joint via direct anterosuperior
and posterosuperior portals. A 2.7 mm arthroscope may be
placed initially if the joint space is narrow.23,38 The capsule
and ligaments of the AC joint are subperiosteally elevated
to expose the distal clavicle, allowing direct visualization of
the clavicle. The meniscus and intra-articular soft tissues are
resected with a 5.0 mm motorized full-radius resector.38 An
electrocautery unit may be used to shell out the outer end of
the clavicle in order to preserve the soft tissue containing the
AC ligaments and capsule.23 After this, if the joint space is
large enough, a 6.0 mm burr is introduced. If the space is too
small, more room can be created using smaller burrs first until
the 6.0 mm burr can be accommodated.Approximately 4 to 7
mm of the distal clavicle is removed.38 After resection, the joint
should be carefully examined arthroscopically from both the
anterior and posterior portals to ensure adequate bone removal
and to check for loose fragments. It is essential to probe the
edges to be sure that no overhanging ridges remain.23 Flatow
and associates reported a 91% success rate with the superior
approach,23 while Zawadsky and colleagues determined that
all results of superior arthroscopic distal clavicle resection of
ADCO were either good or excellent.38
Limited (less than 1 to 2 cm) arthroscopic distal clavicular
resection (DCR), specifically in weightlifters, has shown
promising results.22 The surgical approach consists of a
superior arthroscopic approach to the AC joint with two portals.
22,23,28 Standard arthroscopic instrumentation (30° camera
and 4.0 mm arthroscope), an arthroscopic shaver, and a 4 mm
motorized burr should be used. The AC joint is debrided of
material such as meniscal remnants and cartilaginous debris.
The distal 4 mm of the clavicle is resected with the burr, using
the diameter of the burr as a guide. The outer cortical shell of
the distal clavicle is addressed with the burr after elevating
the capsule from the clavicle with electrocautery, sparing the
superiorAC ligament.A rhinoplasty rasp can be used through
the portals to complete the distal clavicle contouring.22
Experienced weightlifters are accustomed to self-directed
training and biofeedback. Follow-ups of limited DCR on
weightlifters have shown that they can resume their training
within the first week postoperatively (average, 3.2 days; range,
1 to 6 days). Preoperative training levels can be reached by
the second week postoperatively (average, 9.1 days; range 7
to 12 days).Very few patients will lose strength in the military
press or the incline press.22
Although distal clavicle resection has been shown to be a
successful procedure, some failures have been reported. One
of the least recognized reasons of failure may be heterotopic
bone formation. Thus, most investigators recommend removal
of all bone and fragments within the joint in order to avoid a
nidus for new bone formation. Berg and Ciullo suggested that
it might be a more common cause of failure of both acromio
plasty and distal clavicle resection.39 They suggested the use of
prophylactic measures with patients considered at risk. They
found their at-risk group to include patients with hypertrophic
AC joint osteoarthritis that either were long-standing smokers
or had other chronic pulmonary diseases. However, since
periosteal bone formation can be a component of pulmonary
osteoarthropathy, the results could have been attributed to a
low partial pressure of oxygen and tissue hypoxia in their patients.
This is reinforced by the fact that 60% of their patients
had an incidence of chronic pulmonary disease, which was
significantly higher than the United States average.39
Resection of the distal clavicle and disruption of the AC
articulation creates the potential for another complication—
abnormal postoperative motion. Blazar and colleagues studied
17 isolated distal clavicle patients (open and arthroscopic)
and discovered that the average anterior plus posterior
translation was 8.7 mm (range, 3 to 21 mm), which was significantly
greater than the contralateral shoulders (mean, 3.2
mm; range, 1 to 6 mm). The amount of pain determined by a
questionnaire, correlated with the amount of translation and
showed that excessive anteroposterior instability of the distal
clavicle can cause postoperative pain and lead to poor surgical
outcomes.40 In a cadaveric study, Miller and coworkers
determined that there was no statistically significant difference
in the anteroposterior translation between direct or indirect
arthroscopic distal clavicle resections.41 Other complications
include underlying muscle injury, excessive bleeding, lateral
clavicle fracture, and infection.
Conclusions
In summary, distal clavicle osteolysis is a unique disease most
likely due to an overuse phenomenon.When activity modification
and conservative treatment fails to provide relief in an active
patient, distal clavicle resection has provided good results.
In isolated DCO, there is scarcely any indication for an open
procedure, while the superior and subacromial approaches
have their pros and cons. The subacromial approach offers
certain advantages, including: 1. assessing for other pathology
or working through established portals if other pathology is
already being addressed, 2. less injury to the capsule, and 3.
no need for smaller instruments. Disadvantages include: 1.
violating an area with potentially no pathology, 2. more portals,
and 3. more bleeding and fluid extravasation. The merits
of a direct approach should not be discounted.
Disclosure Statement
None of the authors have a financial or proprietary interest
in the subject matter or materials discussed, including, but
not limited to, employment, consultancies, stock ownership,
honoraria, and paid expert testimony.
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