Acromial stress fracture in a young wheelchair user with Charcot-Marie-Tooth disease: a case report

Abstract

: Acromial stress fractures are rare and have not been highlighted as a potential complication of wheelchair use. We report the case of a 22-year old female wheelchair bound patient with Charcot-Marie-Tooth disease who presented with a four-year history of shoulder pain which impaired mobility and quality of life. Plain radiographs showed a cortical irregularity of the acromion but no double-density sign. After CT scans a non-united acromial stress fracture was diagnosed. She had no other shoulder pathology. The new technique of using a superiorly closing wedge osteotomy with cancellous lag screw fixation was successful in correcting the mobile non-united acromial fragment and resolving her pain.

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Cases Journal
Open Access
Case Report
Acromial stress fracture in a young wheelchair user with
Charcot-Marie-Tooth disease: a case report
Randeep S Aujla*, Abhinav Gulihar and Grahame JS Taylor
Address: Orthopaedic Department, Glenfield Hospital, Groby Road, Leicester, Leicestershire, LE3 9QP, UK
Email: Randeep S Aujla* - randeep.aujla@hotmail.co.uk; Abhinav Gulihar - abhinavgulihar@hotmail.com;
Grahame JS Taylor - grahame.taylor@uhl-tr.nhs.uk
* Corresponding author
Acromial stress fractures are rare and have not been highlighted as a potential complication of
wheelchair use. We report the case of a 22-year old female wheelchair bound patient with
Charcot-Marie-Tooth disease who presented with a four-year history of shoulder pain which
impaired mobility and quality of life. Plain radiographs showed a cortical irregularity of the acromion
but no double-density sign. After CT scans a non-united acromial stress fracture was diagnosed.
She had no other shoulder pathology. The new technique of using a superiorly closing wedge
osteotomy with cancellous lag screw fixation was successful in correcting the mobile non-united
acromial fragment and resolving her pain.
Background
Scapular fractures make up less than 1% of all fractures
with only 9% of these involving the acromion [1]. Most
scapular fractures are part of poly-trauma, with 80–90%
of cases having associated injuries [2]. Charcot-Marie-
Tooth disease is a heterogeneous inherited disorder which
causes a lack of proteins in the axon and myelin sheath of
neurones. Consequently there is a sensory and motor neu-
ropathy in the limbs, particularly the lower limbs. It is an
incurable disease which affects up to 23,000 people in the
UK [3]. There has been no reported association of shoul-
der pathology in sufferers. We describe an atraumatic
stress fracture of the acromion occurring in isolation in a
young wheelchair user who suffered with Charcot-Marie-
Tooth disease.
Case presentation
Our patient was a 22-year old Caucasian female who
worked as a council clerk. She had been wheelchair bound
due to Charcot-Marie-Tooth disease for five years and pre-
sented with a four-year history of increasing bilateral
shoulder pain, with the left being significantly worse than
the right. The pain was made worse by fully elevating the
arm but there was no reduction in the range of movement.
Her wheelchair distance was 200 yards before the shoul-
der pain prevented her going further. There was a family
history of shoulder problems with her Father, who was
also wheelchair bound, suffering with a rotator cuff tear.
She was a non-drinker and non-smoker with a BMI of 33.
On examination she had wasting of the muscles in the
hand with poor strength and coordination in the left arm.
There was localised point tenderness over the acromion
and to a lesser extent the acromioclavicular joint. Forward
flexion of the shoulders was to 180° but this caused pain
on the left over the acromion. Glenohumeral abduction
was to 90° bilaterally. External rotation was to 70° and
internal rotation was to the T10 vertebrae bilaterally. Mus-
Published: 28 November 2008
Cases Journal 2008, 1:359 doi:10.1186/1757-1626-1-359
Received: 17 October 2008
Accepted: 28 November 2008
This article is available from: http://www.casesjournal.com/content/1/1/359
© 2008 Aujla et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Cases Journal 2008, 1:359 http://www.casesjournal.com/content/1/1/359
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cles of the rotator cuff had normal power. There were no
clinical signs of impingement, with no low painful arc
and negative Hawkins test.
Initial radiographs showed an irregularity of the acromion
which was considered to be either an os acromiale or an
acromial stress fracture (Fig. 1). CT scans showed a 1 cm ×
1.8 cm fragment at the anterior aspect of the acromion
that had features consistent with a non-united stress frac-
ture of the acromion, such as bony hypertrophy and sharp
irregular bone edges (Fig. 2 &3). Rockwood et al described
these changes and contrasted them to radiographic fea-
tures of an os acromial, which would have had rounded
uniform cleavage lines [4].
At time of surgery it was noted that the fragment was
mobile and too large to excise. The non-united fracture
was then corrected using a superiorly closing wedge exci-
sion osteotomy and fixated with two partially threaded
cancellous lag screws (Fig. 4 &5). This osteotomy was used
to help elevate the anterior acromion and reduce the like-
lihood of future impingement. A sub-acromial decom-
pression was performed at the same time. The patient
remained in a poly-sling for six weeks with only pendu-
lum exercises permitted for the first two weeks. Passive
movements were allowed thereafter until union of the
fracture at six weeks. After out-patient follow-up at six
weeks active movements were initiated. At 6 months fol-
low-up the patient reported no problems, having equal
range of movement bilaterally and a pain free left shoul-
der.
Discussion
Shoulder pain is reported in 30–40% of wheelchair users.
The forces on the shoulder joint are considerable and
increase four-fold with rising up an incline and fast wheel-
ing [5]. Numerous pathologies have been linked with
wheelchair use, such as rotator cuff impingement, gleno-
humeral instability, and biceps tendonitis [6].
Clinical history and examination rarely differentiates os
acromiale and acromial stress fractures, with both demon-
strating point tenderness and pain in the shoulder on full
elevation. AP and axillary view shoulder radiographs can
reveal a double-density sign or cortical irregularities
which are 94.1% sensitive and 100% specific for diagnosis
of os acromiale [7]. From our experience small fragments
may not be visible on plain radiographs and may require
further imaging. Therefore CT scans should be considered
in wheelchair users presenting with shoulder pain if plain
radiographs reveal little. Cannulated screws with tension
band wiring have been proven to be successful in treating
os acromiale [8].
Stress fractures are more common in the lower limb. Acro-
mial stress fractures, or symptomatic os acromiale, should
be considered in both young and old wheelchair bound
patients who present with shoulder pain.
Pre-operative axial radiograph of the left shoulderFigure 1
Pre-operative axial radiograph of the left shoulder. It shows
an irregularity of the acromion which is poorly visualised. No
double density sign is visible.
Pre-operative coronal computer tomography image of the left shoulderFigure 2
Pre-operative coronal computer tomography image of the
left shoulder. It shows the fracture of the acromion with an
irregular margin and hypertrophy at the superior aspects of
the bony ends. The size of the fragment can also be appreci-
ated.

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Upon literature review we uncovered eight previous
reported cases of acromial stress fracture [2,9-13]. Three
occurred in sports athletes, one of which was after sub-
acromial decompression surgery [2,10,11]. The remaining
five cases were all over 64 years of age, four had associated
rotator cuff tears, two were on long-term steroids and one
was a wheelchair user [9,12,13].
Our patient was much younger than the other reported
cases in non-athletes. She had no associated rotator cuff
tear and did not take steroids. Also her bone quality was
noted to be good during surgery and it is unlikely a 22-
year old would be suffering from osteoporosis, but no for-
mal bone density testing was performed. Her only risk fac-
tor was her wheelchair use.
Seven out of the eight reported cases were treated conserv-
atively with immobilisation and physiotherapy. Of these
seven, three united, one developed an asymptomatic non-
union and three progressed to excision of the fragment
with a subsequent good outcome [2,9,10,12,13]. Only
one case was managed surgically using two Kirschner
wires and a tension band suture [11]. This was performed
in a professional tennis player three months after a sub-
acromial decompression.
Our presented technique offered a good compression of
the osteotomy and a low risk of metal migration which
has been reported with use of wires around the shoulder
[14]. We appreciate that this technique may not be suc-
cessful in elderly patients with osteoporotic bone and in
these patients surgical excision of the distal fragment may
be a better option.
Conclusion
This case report highlights acromial stress fractures as a
potential complication of wheelchair use. The technique
of using a superiorly closing wedge osteotomy of the
acromion with partially threaded cancellous lag screws to
compress the osteotomy led to a successful clinical out-
Pre-operative axial computer tomography image of the left shoulderFigure 3
Pre-operative axial computer tomography image of the left
shoulder. It shows the ragged bone edges which is indicative
of an acromial stress fracture.
Six weeks post-operative axillary view of the left shoulderFigure 4
Six weeks post-operative axillary view of the left shoulder.
The two lag screws are seen completely within the bone.
The fracture has healed with no fracture line visible.
Six weeks post-operative axial view of the left shoulderFigure 5
Six weeks post-operative axial view of the left shoulder. The
fracture has united with the screws still within the bone.

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Cases Journal 2008, 1:359 http://www.casesjournal.com/content/1/1/359
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come and has not been previously described. Also the
acromial fracture was poorly visualised with standard
shoulder radiographs and CT scans provided a clearer
diagnosis.
Abbreviations
BMI: Body mass index; CT: Computerized tomography.
Consent
Written informed consent was obtained from the patient
for publication of this case report and accompanying
images. A copy of the written consent is available for
review by the Editor-in-Chief of this journal.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
RSA analysed and interpreted the patient history and clin-
ical outcome. He also researched on all aspects of the
report and was the main writer of the manuscript. AG and
GJT were involved in the clinical management of the
patient and were both contributors in writing the manu-
script. All authors read and approved the final manu-
script.
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