Download Stress injury of the acromion: case report and literature review

Eur J Orthop Surg Traumatol
DOI 10.1007/s00590-013-1181-6
UP-TO DATE REVIEW AND CASE REPORT
Stress injury of the acromion: case report and literature review
Atul Kumar Taneja • Francisco Pires Negromonte
Abdalla Skaf
•
Received: 29 December 2012 / Accepted: 27 January 2013
Ó Springer-Verlag France 2013
Abstract We report a case of stress injury of the acromion related to golf practicing in a 40-year-old male.
Fractures of the scapula are unusual, with stress injury of
the acromion being even rarer. The probable mechanism
would be a strong contraction of posterior fibers of the
deltoid during golf swing. There are few published reports
of similar injuries, and to our knowledge, this is the first to
demonstrate its features by magnetic resonance imaging. A
review of the literature is also presented.
Keywords Stress fracture Acromion Shoulder Golf Magnetic resonance imaging
plain radiographs and healed with conservative treatment.
We report a case of stress injury of the acromion related to
golf practicing in a 40-year-old male diagnosed by magnetic resonance imaging (MRI). Golf may be a demanding
sport, and the mechanism suggested would be a strong
contraction of posterior fibers of the deltoid during the
swing forward to strike the ball [7]. MRI is especially
helpful in stress injuries and non-displaced fractures.
Therefore, early recognition by radiologists and orthopedics surgeons is of utmost importance to prevent causative
activity and perform adequate treatment regimen.
Case report
Introduction
Injuries of the acromion may result from multiple mechanisms, with only few cases of stress injuries being reported
so far [1–6]. Most cases of stress injuries of the acromion
published were minimally displaced fractures diagnosed by
A. K. Taneja F. P. Negromonte A. Skaf
Departamento de Radiologia Musculoesquelética, Hospital do
Coração (HCor) and Teleimagem, São Paulo, Brazil
A. K. Taneja
Musculoskeletal Imaging and Intervention Division,
Massachusetts General Hospital, Harvard Medical School,
Boston, MA, USA
A. K. Taneja (&)
Teleimagem, R. Des. Eliseu Guilherme,
N. 53, 7. Andar, São Paulo, SP 04004-030, Brazil
e-mail: [email protected]
A. Skaf
Alta Diagnósticos, São Paulo, Brazil
A 40-year-old right-handed man presented with history of
pain on his right shoulder that begun while playing amateur
golf 1 month earlier. Just before he hit the ball off the tee,
he felt a sudden pain on the posterior and superior aspect of
the shoulder. He felt pain in non-specific movements while
he continued to play during that day and the following few
days, even after starting taking oral painkillers during a
total of 5 days. Neither other injuries nor other sports
activities were reported in the following weeks after the
golf play. He was otherwise healthy, without any history of
serious musculoskeletal injury, systemic disease, or bone
disorder. Clinical examination revealed mild swelling and
focal tenderness over superior and posterior region of the
right shoulder. There was complete range of motion.
Plain radiographs of the shoulder were performed at
another institution and reported to be normal. MRI scan of
the right shoulder was performed at our facility using the
following pulse sequences: axial proton density (PD)weighted fat-suppressed [TR/TE = 2,870/37; number
of excitations (NEX) = 2; slice thickness = 3.0 mm;
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Eur J Orthop Surg Traumatol
matrix = 320 9 320], coronal T2-weighted fat-suppressed
(2,200/42; 1; 3.5 mm; 256 9 256), sagittal T2-weighted
fat-suppressed (2,570/46; 2; 4.0 mm; 320 9 320), sagittal
PD-weighted (1,500/23; 2; 4.0 mm; 384 9 384), and
coronal T1-weighted (400/11; NEX 1; 3.5 mm;
384 9 384). MRI revealed extensive bone marrow edema
of the acromion, represented by increased signal intensity
(SI) on T2-weighted fat-suppressed images (Fig. 1). Also, a
marked hypointense thin line on PD-weighted images was
depicted at the acromion base, next to the posterior deltoid
muscle attachment site, which could illustrate a small nondisplaced linear fracture (Fig. 2). Minimal tendinopathy of
the supraspinatus and infraspinatus was also seen, as well
as mild degenerative changes of superior glenoid labrum.
The association of clinical history of sudden shoulder
pain during golf swing, focal tenderness at the acromion
site on clinical examination and MRI findings, was suggestive of stress injury of the acromion. The intensity of the
edema and a possible thin fracture demonstrates the
acuteness of the injury.
The patient underwent conservative treatment with nonsteroidal anti-inflammatory drugs for 2 weeks, and rest for
4 weeks. Then, physical activities were gradually reintroduced during following 2 months. Physical evaluation of
the patient after 3 months of injury did not revealed pain,
and muscle strength was normal. Routine activities and
sports were restored without any further complications or
recurrence of pain.
Discussion
Fractures of the scapula infrequently occur, with stress
injury of the acromion being an even uncommon entity [1].
Fractures of the acromion may be due to multiple causes
and are mostly secondary to trauma [2] and more recently
have also been reported following surgery with reverse
shoulder arthroplasty [8, 9], with few cases of stress lesions
reported so far [1, 3]. Previous reports have described
acromion stress fractures visible on radiographs at its different anatomic points (Table 1), but to our knowledge, no
report in the literature showed MRI features of such entity.
Stress injuries are usually due to abnormal muscular
strength applied to a bone with normal resistance [6].
Repetitive loads or a single muscle contraction is a common mechanism of stress fracture of legs, but in the upper
extremity this cause is less common, specially at the
scapula because it is well protected and highly mobile [3,
4].
The only reported case of similar injury related to golf
practice was done by Hall and Calvert [4], in a 42-year-old
right-handed woman with a similar history (during golf
practice), that presented a linear fracture at the base of the
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Fig. 1 Sagittal (a), coronal (b), and axial (c) T2-weighted fatsuppressed MR images show extensive bone marrow edema at the
acromion (arrow) extending to its base (arrowheads), close to the
attachment site of posterior deltoid muscle (curved arrows)
Eur J Orthop Surg Traumatol
Fig. 2 a and b Sagittal PD-weighted MR images show a hypointense
thin line at the acromion base, which could represent a small nondisplaced linear fracture (arrows)
acromion visible on plain radiograph. The mechanism
suggested would be a strong contraction of the posterior
fibers of the deltoid as the head of the golf club swing
forward to strike the ball [10], which reminds our case. The
bone may also be repeatedly stressed by shots over a short
period of time, although there was no history of an
excessive amount of golf practice neither in our case nor in
the case reported by Hall and Calvert [4].
Acromion injury due to muscle forces related was also
reported by Rask and Steinberg [5], but in a different situation, where a car mechanic heard a snap and felt pain
over his shoulder while applying torque to a screwdriver,
and plain radiograph demonstrated a minimally displaced
fracture at the base of the acromion. With the scapula fixed
and the deltoid set while holding the shoulder in abduction,
probably the adduction and external rotation of the arm
during tightening the screw did sufficient bending movement to cause the fracture of the acromion [5].
Another mechanism suggested in the literature is the
abnormal pressure from the humeral head on the acromion
in the set of rotator cuff arthropathy, as reported by Dennis
et al. [2] and Roy et al. [3]. In our patient and in most of the
previously reported cases [4–6], there was no rotator cuff
arthropathy or violent activity. The most reasonable
explanation would be repetitive subcritical load to the
shoulder or a single powerful muscle contraction leading to
excessive overload at the acromion during the specific
activity related by the patient: golf practicing.
Although usually seen as a leisurely activity, golf can be
a demanding sport and may result in serious injuries,
especially regarding the shoulder. Professional and elitelevel golfers often acquire overuse injuries as a result of
repeated swings during practice sessions, but also amateur
golfers may suffer either from overuse as they work to
improve their game or bad technique. The complete golf
swing movement is divided into five phases: (1) takeaway
(from address until the club is horizontal), (2) backswing
(from horizontal to top of backswing), (3) downswing
(from top of backswing until the club is horizontal), (4)
acceleration (from horizontal club to impact), and (5) follow-through (from ball contact until end of swing). To
generate power and clubhead speed, the skilled golfer will
Table 1 Previous published case reports of stress fractures of the acromion, listed by year
Author
Year
Anatomic location
Related activity
Rask and Steinberg [5]
Dennis et al. [2]
1978
1986
Neck of acromion
Anterior aspect of acromion (3 cases)
Applying torque to set a screw above head
Chronic rotator cuff arthropathy and osteoporosis
Schils et al. [6]
1990
Medial aspect of acromion
Professional football player
Hall and Calvert [4]
1995
Base of acromion
Amateur golf player
Ward et al. [1]
1994
Base of acromion (2 cases)
Professional football player and jai alai player
Roy et al. [3]
2002
Base of acromion
Chronic rotator cuff arthropathy and osteoporosis
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maximize the shoulder turn relative to the hip turn during
the backswing, and in a right-handed golfer, the right
posterior deltoid muscle is active mostly during takeaway
and backswing [7]. Regarding our case, the correct time of
the reported sudden pain is difficult to precise, since in
amateurs these phases are not well defined, but it seemed to
occur during the transition from backswing to downswing.
Most stress injuries of the acromion reported were
minimally displaced fractures and healed with conservative
treatment, such as immobilization for few weeks followed
by gradual motion [2]. As in the typical stress injury, it is
important to recognize the pathologic process, with MRI
being helpful in theses cases; some of these fractures may
even become complete, non-united, or evolute to pseudarthrosis if causative activity is continued [2, 6]. Also,
benefits may be obtained with modifications of the golf
swing [7], especially in amateur players.
Conflict of interest
None.
References
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