Vol.2, No.4, 318-320 (2010) Health
doi:10.4236/health.2010.24048
Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
Acceleration of coxarthrosis by an exostosis causing
femoroacetabular impingement
Mahmut Nedim Aytekin1, Hakan Atalar1, Burcu Yanik2, Murat Arikan3
1Department of Orthopedics and Traumatology, Fatih University Hospital, Ankara, Turkey; [e-mail]
2Department of Physical Therapy and Rehabilitation, Fatih University Hospital, Ankara, Turkey
3Department of Orthopedics and Traumatology, Ankara On co logy State Hospital, Ankara, Turkey
Received 18 November 2009; revised 4 January 2010; accepted 8 January 2010.
ABSTRACT
Here we describe a 28-year-old man with a his-
tory of right hip pain for the past 11 years and
ankylosing spondylitis for the past 6 months.
Imaging studies showed an exostosis in the
femoral neck causing femoroacetabular imping-
ement. The patient was diagnosed with coxar-
throsis. This case report suggests that femoro-
acetabular impingement may accelerate the de-
generative process in the hip joint.
Keywords: Femoroacetabular Impingement; Exostosis
1. INTRODUCTION
Femoroacetabular impingement, also known as hip im-
pingement syndrome, refers to a condition in which the
femoral head-neck junction impinges upon the acetabu-
lum, thereby being a potential cause of hip osteoarthritis
[1,2]. Two types of impingement are defined according
to the anatomic structures involved. Cam impingement
occurs when the contact arises from an abnormality in
the femur and pincer impingement is defined as that
which results when the abnormality originates from the
acetabulum [3]. Both types are characterized by damage
to the acetabular labrum and articular cartilage in the hip
[4,5]. These changes lead to degenerative osteoarthritis
in the long term [5,6]. Here, we describe a patient who
has femoroacetabular impingement due to a bone mass in
the femoral neck and coxarthrosis. We could not found
any case which demonstrates acceleration of coxarthrosis
by an exostosis causing femoroacetabular impingement
in the literature.
2. CASE REPORT
A 28-year-old male presented at our hospital with a his-
tory of right hip pain for the past 11 years which had
become increasingly worse in the past 3 years, up to the
point at which he decided to seek treatment. He was cur-
rently working as a waiter. Six months prior to this pres-
entation he had been diagnosed with ankylosing spondy-
litis and was currently taking salazoprine, methotrexate
and indomethacin regularly. He was a nonsmoker and
had no history of athletic activity which could explain his
findings. He also reported having back pain and morning
stiffness for the past 3 years.
On physical examination of the right hip, flexion, ab-
duction, external ro tation and external rotation were lim-
ited. There was 45 degree maximum flexion, 10 degree
maximum extension and 10 degree maximum abduction
in the right hip joint. In ternal and external rotation of th e
right hip was also markedly restricted. Anteflexion, ex-
tension and lateral bending of the lumbar region were
limited.
Pelvic x-ray showed an exostosis in the right femoral
neck. Also visible in the right hip were narrowing of the
hip joint, subchondral sclerosis and osteophytes. There
was also sclerosis and narrowing in the sacroiliac joint,
indicating bilateral sacroileitis which is a finding of an-
kylosing spondylitis (Figure 1). CT and MRI demonstrated
Figure 1. An anteroposterior pelvic radiograph shows cam
impingement due to exostosis of the femoral neck and cox-
arthrosis in the right hip.

M. N. Aytekin et al. / Health 2 (2010) 318-320
Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/HEALTH/
319
femoroacetabular impingement caused by the exostosis
(Figures 2,3).
Conservative treatment has been decided upon for the
time being because the patient is young and can still
perform his activities of daily life.
3. DISCUSSIONS
Femoroacetabular impingement has been recognized as
Figure 2. Coronal computed tomography of the right hip dem-
onstrates femoroacetabular cam impingement due to an exosto-
sis in the femoral neck and findings of coxarthrosis.
Figure 3. Magnetic Resonance Imaging of the right hip demon-
strates femoroacetabular cam impingement due to an exostosis
in the femoral neck and findings of coxarthrosis.
an underlying cause of hip pain and secondary os-
teoarthritis [1] and occurs in two main forms: cam-type
impingement and pincer-type impingement. Cam-type
impingement occurs when the anterior femoral neck ab-
normally impinges on the on the acetabulum and labrum,
resulting in damage to the labrum [7,8]. Pincer-type im-
pingement occurs when an osteophyte on the anterior
acetabulum impinges on the anterior femoral neck during
hip flexion or retroversion of the acetabulum [9,10].
We found cam-type impingement due to the exostosis
on the femoral neck in our patient. For the coxarthrosis
that developed, another possible etiological factor was
the ankylosing spondylitis; however, the patient had no
other risk factors for coxarthrosis such as smoking, al-
coholism, steroid use, obesity, female gender, repetitive
occupational trauma, or neuromuscular or metabolic dis-
orders. Protrusio acetabuli may develop in as many as
one third of patients and hip joint involvement typically
is bilateral and symmetric. Absence of the protrusion of
the both acetabulum and the unilateral nature of the cox-
arthrosis suggest that the impingement caused by the
exostosis had accelerated the degeneration of the hip
joint.
Although there are a range of treatment options for hip
impingement syndrome [1], nonsurgical treatment gener-
ally does not control symptoms [11]. By preventing mi-
crotrauma, early treatment may help preserve the joint by
averting the impingement that may lead to coxarthrosis
[8]. Our patient presented later in the course of the dis-
ease, with hip osteoarthritis symptoms that were appar-
ently due indirectly to th e nearby tumor, which itself was
not painful.
In conclusion, femoral neck exostosis may accelerate
the progression of coxarthrosis by cam impingement.
Early diagnosis is therefore important in preventing this
degenerat i ve p rocess.
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