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Stress fracture of the ulna associated with
bisphosphonate therapy and use of walking
C. S. H. Grace, K. W. B. Kelvin,
C. T. Wei & T. B. Yeow
Osteoporosis International
With other metabolic bone diseases
ISSN 0937-941X
Osteoporos Int
DOI 10.1007/s00198-014-2739-9
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Author's personal copy
Osteoporos Int
DOI 10.1007/s00198-014-2739-9
Stress fracture of the ulna associated with bisphosphonate
therapy and use of walking aid
C. S. H. Grace & K. W. B. Kelvin & C. T. Wei & T. B. Yeow
Received: 16 March 2014 / Accepted: 1 May 2014
# International Osteoporosis Foundation and National Osteoporosis Foundation 2014
Abstract We report a case of a stress fracture of the ulna
secondary to long-term bisphosphonate therapy and walking
cane. Physicians need to have a high index of suspicion of
stress fractures occurring in patients complaining of chronic
upper limb pain if they are on bisphosphonate therapy and are
using walking aids. Stress fractures of the upper extremities
are rare and are usually associated with athletes; however, a
few recent case reports have shown an association between
stress fractures of the upper extremities and the use of walking
aids. The association between increased incidence of upper
extremity stress fractures and the use of both bisphosphonates
and walking aids in patients has not been well studied, with
only one previously reported case. Here, we report a case of a
complete stress fracture of the ulna in a 77-year-old female,
premorbidly ambulant with walking cane, on long-term
bisphosphonates without any pre-existing medical conditions
which could result in secondary causes of bone loss.
Investigations did not reveal any causes of pathological fracture. This fracture is attributed to the use of long-term bisphosphonate therapy in conjunction with the use of a walking
cane. This case highlights the importance of entertaining the
possibility of such fractures occurring in any patient who is on
bisphosphonate therapy presenting with stress fractures of the
upper extremity.
Keywords Bisphosphonates . Stress fractures . Upper
extremities . Walking aids
C. S. H. Grace (*)
National University Health System, 1E, Kent Ridge Road,
Singapore 119228, Singapore
e-mail: [email protected]
K. W. B. Kelvin : C. T. Wei : T. B. Yeow
St. Luke’s Hospital, 2 Bukit Batok Street 11, Singapore 659674,
Osteoporosis is a major global public health problem especially
with the rapidly aging population; the World Health
Organization (WHO) data predicts average life expectancy of
men to be 75 years and women to be 80 years. Worldwide,
osteoporosis affects approximately 200 million women [1] and
causes more than 8.9 million fractures annually leading to
increased morbidity and mortality [2]. Osteoporosis-related
fractures cause significant medical and personal toll on individuals and economic burden on the nation; the cumulative cost
over the next two decades is estimated to be US$474 billion [3].
Osteoporosis can be diagnosed early and treated before
fractures occur. There is a range of drug treatments available
for osteoporosis, of which, bisphosphonates are the first-line
therapy and the most widely used in view of their anti-fracture
efficacy [4].
While studies have shown that bisphosphonates prevent
future vertebral and non-vertebral fractures in patients with
osteoporotic fractures, post-menopausal women with osteoporosis, and men with osteoporosis [5, 6], there has been increasing evidence of bisphosphonate use leading to atypical fractures especially of the femur [7, 8]. Limited data on atypical
fractures of long bones other than the femur is available [9–11].
Prolonged bisphosphonate therapy has been associated with
over-suppression of bone turnover and increased skeletal fragility [9]. Stress fractures result from the suppression of intracortical
remodeling, hence impairing normal bone healing [10]. We
report a case of atraumatic stress fracture of the ulna secondary
to long-term alendronate use in a patient using a walking cane.
Case summary
A 77-year-old Chinese female was started on alendronate for
osteoporosis in 2004. Nine years after starting alendronate,
Author's personal copy
Osteoporos Int
she suffered an atraumatic fracture of the right ulna requiring surgical fixation. The patient had noted pain of
her right forearm for 3 months; however, pain had worsened when she had transferred more weight to her right
forearm whilst ambulating with a walking cane. X-ray of
the right forearm showed a transverse fracture of the
proximal shaft of the right ulna with increased sclerosis
around the fracture (Fig. 1).
She has a past medical history of multiple fractures. She
had sustained a left medial tibial condyle and fibula neck
fracture in 1999 after a fall which was managed conservatively. In 2001, she was discovered to have multiple vertebral
compression fractures and she had been experiencing lower
back pain and an X-ray was done. In 2004, she sustained a
right intertrochanteric fracture after falling and underwent a
bipolar hemiarthroplasty. Bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DEXA) revealed
T-score of lumbar spine to be −3.8 with a density of 0.54 g/
sq cm2 and she was started on alendronate. In 2010, she
sustained a left distal radial fracture after a mechanical fall,
which was managed conservatively.
Her risk factors were reviewed. She was quite active
premorbidly, ambulating with walking cane for 6 years and
carrying out daily activities of living independently. She did
not have premature menopause. She is a non-smoker and nondrinker. She was not on any other long-term medications and
no history of steroid use. There was no history of significant
weight change or change in bowel habits. During physical
Fig. 1 Right forearm X-rays
show a slightly displaced
transverse fracture of the
proximal shaft of the right ulna
with increased sclerosis around
the fracture. The bones appear
diffusely osteopenic
examination, there was deformity of the right forearm with
tenderness, but neurovascularly intact.
Laboratory work-up showed corrected calcium 2.28 mmol/
L, 8:00 a.m. cortisol 435 nmol/L, thyroid stimulating hormone
2.16 mIU/L, parathyroid hormone 4.6 pmol/L, and 25hydroxy vitamin D level 35.8 μg/L. Myeloma panel was not
suggestive of multiple myeloma. Her bone density did not
decrease between 2005 and 2012. In 2012, the bone density of
the spine was 0.56 g/sq cm2 with a T-score of −3.8. Bone scan
showed that there was no scintigraphic evidence of bone
metastasis. Magnetic resonance imaging of the right elbow
showed a midshaft ulna fracture; no underlying pathological
lesions were seen (Fig. 2).
In view of the atraumatic nature of the fracture, X-ray
findings distinctive of atypical fractures, and further investigations excluding other causes of atypical fractures,
the diagnosis of atypical ulna shaft fracture secondary to
long-term alendronate use was made and alendronate
was discontinued.
The fracture was fixed with plates and screws.
However, 3 weeks after surgical fixation, deformity over
the right forearm open reduction internal fixation site was
noted. X-ray of the right ulna showed a peri-implant fracture with displacement of screws. She subsequently
underwent removal of the implant and re-fixation with
bone grafting. She recovered well and was later discharged
to a rehabilitation hospital for physical and occupational
Author's personal copy
Osteoporos Int
Fig. 2 Magnetic resonance
imaging of the right elbow shows
a stress fracture of the midshaft of
the ulna fracture as a linear area of
low signal intensity. There
isoedema within the soft tissues
and at the site of the fracture. No
underlying pathological lesions
were seen
Long-term bisphosphonate use has been found to increase the
relative risk of atypical fractures [7, 8]. While there is strong
evidence to suggest that bisphosphonate use is associated with
atypical fractures of the femur [11, 12], the relation between
bisphosphonate use and atypical fractures of the upper limb
has not been well studied [13].
Prolonged use of alendronate may be associated with stress
fractures [5]; it is believed that the long-term over-suppression
of bone turnover impairs the ability of bone to remodel,
causing microdamage to persist which compromises bone
strength leading to stress fractures [11]. Common clinical
features of atypical fractures associated with bisphosphonate
use are prodromal pain occurring for weeks to months prior to
the fracture, typically sharp and well localized [11]. These
fractures are usually atraumatic. Radiographic features of
atypical fractures associated with bisphosphonate use are a
transverse fracture line, beaking of the cortex on one side and
bilateral thickened diaphyseal cortices [9].
Upper extremity stress fractures are rare and can occur
in athletes [14, 15] and those using walking aids [9, 16,
17]. It is postulated that the likely mechanism of injury
with walking aids is a combination of tractional and torsional force, together with direct pressure on the proximal
forearm bones.
In our patient, it is probable that the fracture was a stress
fracture secondary to both long-term alendronate use and
walking aids. This patient had presented with an isolated
transverse midshaft ulna fracture; however, it was atraumatic
unlike the usual mechanism of injury for isolated midshaft
ulna fractures which is a blunt trauma to the forearm when it is
being held in protection across the face. Furthermore, she
presented with classical symptoms associated with atypical
bisphosphonate fractures; radiographic findings likewise
showed the typical transverse fracture line and increased
sclerosis around the fracture. Investigations done for this
patient did not reveal any cause of pathological fractures or
secondary causes of bone loss. The patient reported here was
ambulating with a walking cane. The stress fracture is likely to
have resulted from the high tensional stress caused by weight
bearing on the walking cane where the wrist is in a position of
flexion and axial load is increased though the ulna. The longterm use of alendronate in this case may have resulted in
increased brittleness of the bones as bone turnover is inhibited,
thus leading to increased mineralization and accumulation of
microdamage [8].
This case highlights that physicians need to have a high
index of suspicion of upper extremity stress fractures
occurring in patients who complain of chronic upper limb
pain if they are on bisphosphonate therapy and are using
walking aids. To facilitate early detection, it is essential
that both physicians and patients be aware of the possibility of such fractures occurring and the signs and symptoms associated with these fractures. It is critical to comprehensively investigate such patients with radiographs
looking for stress reaction and, if necessary, advanced
imaging such as bone scan or magnetic resonance
imaging should be considered. Bisphosphonates should
be discontinued in patients with stress fractures secondary to
bisphosphonate therapy.
Conflicts of interest None.
Author's personal copy
Osteoporos Int
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