Jt Dis Relat Surg
Joint Diseases and
Related Surgery

2020;31(2):386-389

CASE REPORT

Post-stroke bilateral heterotopic ossification:
An acute problem with long-lasting consequences
Selin Ozen, MBBS BSc, Huma Bölük Şenlikci, MD, Oya Ümit Yemişci, MD
Department of Physical and Rehabilitation Medicine, Başkent University Faculty of Medicine, Ankara, Turkey

Neurogenic heterotopic ossification (HO) is a
complication of injury to the central nervous system
in which production of lamellar bone within the
soft tissues occurs resulting in pain and reduced
range of motion (ROM) with eventual ankylosis and
loss of functional capacity.[1] Heterotopic ossification
is frequently seen as a complication of total hip
arthroplasty[2] and in approximately 20% of traumatic
brain injury and spinal cord injury patients.[3]
Following stroke, HO most commonly involves the
hip joint,[4,5] occurs on the paretic side and rarely on
the non-paretic side.[6,7] Bilateral HO following stroke
is even rarer with the most recent cross-sectional
study identifying bilateral HO in only 0.2% of all
stroke patients over a 10 year period.[8] In this article,
we present a case of extensive established bilateral
HO of the hips occurring shortly after the onset of
stroke.

CASE REPORT
A 77-year-old female patient with a five-month
history of stroke, right-sided weakness and left knee
contracture presented to our Physical Medicine and
Rehabilitation Department. Following the onset of
stroke, the patient was initially treated in an intensive
care unit (ICU) before being transferred to the

Received: November 04, 2019
Accepted: February 05, 2020
Published online: June 18, 2020

Correspondence: Selin Ozen, MD. Başkent Üniversitesi
Tıp Fakültesi Fiziksel Tıp ve Rehabilitasyon Anabilim Dalı,
06490 Bahçelievler, Ankara, Türkiye.
E-mail: selinhassan@hotmail.com
Doi: 10.5606/ehc.2020.72081
Citation: Ozen S, Bölük Şenlikci H, Ümit Yemişci O. Post-stroke
bilateral heterotopic ossification: An acute problem with longlasting consequences. Jt Dis Relat Surg 2020;31(2):386-389.

ABSTRACT
Heterotopic ossification (HO) is a complication of injury to the
central nervous system in which production of lamellar bone
within the soft tissues occurs resulting in pain, reduced range
of motion (ROM) and loss of functional capacity. Heterotopic
ossification is rarely seen in stroke patients and mostly affects
the paretic side. In this article, we present a case of established
bilateral HO of the hips soon after stroke onset. A 77-year-old
female patient with a five-month history of stroke presented to our
rehabilitation clinic. Physical examination revealed sensorimotor
aphasia, right-sided hemiplegia, bilateral painful limited ROM of
the hips and left knee contracture. An anteroposterior X-ray of the
pelvis revealed previously undiagnosed bilateral HO of the hips.
The patient and her relatives declined operative interventions.
The patient was discussed in the departmental meeting and it
was agreed that she would not be able to partake in an active
inpatient rehabilitation program. She was discharged with a home
exercise plan. This case highlights the importance of HO, of both
the paretic and non-paretic side, being included in the differential
diagnosis of post-stroke patients presenting with joint pain and
reduced ROM, both acutely and in the long-term. This may aid the
timely diagnosis and management of HO, a pathology which has
detrimental effects on functionality.
Keywords: Bilateral, hemiplegia, heterotopic, hip, ossification, stroke.

neurology ward. Following discharge from the ward,
a monoarthritis of the left knee developed. According
to the patient’s relatives, the patient’s knee was
evaluated by an orthopedics and traumatology team;
however, no details of the evaluation/investigations/
treatment applied are known. To date, the patient had
not partaken in a home exercise program or received
physical therapy. The patient’s past medical history
included hypertension, atrial fibrillation, heart
failure and a right total knee replacement five years
previously due to osteoarthritis. Prior to development
of the stroke, the patient was independent of activities
of daily living.
Physical examination revealed a Glasgow Coma
Score of 12 with motor and sensory aphasia. There

Post-stroke heterotopic ossification

FIGURE 1. Bilateral heterotopic ossification of hips.

was a flaccid paralysis of the right side. No spasticity
was detected. The patient was incontinent of urine
and feces. Examination of the musculoskeletal system
revealed bilateral painful and limited ROM of the
hips and left knee contracture. There was no effusion
of the joints. The patient’s Functional Independence
Measure[9] score was 23.
The patient’s initial routine blood tests were
normal. The erythrocyte sedimentation rate
was 69 mm/hour and the C-reactive protein
was 11.4 mg/L. An anteroposterior X-ray of the

387

pelvis revealed extensive bilateral periarticular
HO (Figure 1). A two-way bilateral X-ray of the
knees revealed a total knee replacement on the
right side and extensive osteoarthritis of the left
knee (Figure 2). Pharmacological treatment with
indomethacin was commenced. The Orthopedics
and Traumatology Department was consulted for
further management of the bilateral hip HO and left
knee contracture. Initially, arthroscopic debridement
of the left knee was recommended; however, the
patient’s relatives did not consent to the procedure.
Due to the patient’s limited cooperation, immobility,
poor right-sided motor recovery, bilateral limited
hip movement and left knee contracture, it was
decided that she would gain little benefit from an
active inpatient rehabilitation program. The patient
was discharged with appropriate analgesia and a
home exercise plan with a view to follow-up in the
outpatient clinic in a month’s time.

DISCUSSION
Bilateral HO occurring soon after stroke is a subject
which remains scarcely covered in the literature.[10,11]
A recent cross-sectional study by Cunha et al.[8] of
stroke patients admitted to seven rehabilitation
centers over a period of 10 years found an annual
prevalence of HO of 1.3%.[8] Moreover, only 0.2% of
the cases identified had bilateral HO.
In this case, the early diagnosis of HO of the hips
was missed. The early stages of HO and resultant hip

FIGURE 2. Osteoarthritis and varus deformity of left knee joint.

388

pain may not have been detected due to the patient’s
poor cognitive function and immobility. For the
affected patient, it is crucial that this condition is
recognized and diagnosed early so that ankylosis
can be prevented by timely treatment.[12] The fact that
there was bilateral established HO by the time the
diagnosis was established underlines the fact that
awareness on this matter requires further attention,
particularly in bed-bound patients in which hip
examination may be more challenging. Often,
patients initially experience pain and inflammation
of the affected joint; therefore, differential diagnoses
such as spasticity, monoarthritis and cellulitis may
primarily come to mind resulting in a diagnosis of
HO being overlooked.[13,14]
Moreover, complications associated with HO such
as urinary tract infections, deep vein thrombosis and
overlying pressure ulceration[15,16] deem early and
correct management imperative.
Management of HO is often targeted at preventing
the condition from occurring in unaffected patients.
Single-dose radiotherapy or oral nonsteroidal antiinflammatory drugs such as indometacin and
maintaining joint ROM post-stroke are used as HO
prophylaxis and treatment.[17] Preliminary studies
and case reports on the role of extracorporeal shock
wave therapy (ESWT) in the treatment of neurogenic
HO following traumatic brain injury and spinal
cord injury suggest that ESWT may reduce pain and
increase ROM of the affected joints;[18-20] however,
excisional surgery remains the treatment of choice to
restore joint mobility.[6,21] In this case, the contracture
of the osteoarthritic left knee may have developed
secondary to the neurogenic HO of the hips, as this
results in reduced mobility and poor positioning of the
patient within bed. Therefore, surgical intervention to
the left knee was initially offered to the patient.
Causative factors for the development of
HO remain to be elucidated. Recent studies of
stroke patients have concluded that the presence
of hemorrhagic stroke/ischemic stroke with
hemorrhagic transformation, severity of the
initial neurological lesion, presence of spasticity
and cognitive impairment are risk factors for the
development of HO.[5,7,8,22] Cases of severe HO, such
as the case reported here, involve two or more joints
and have been associated with ICU stay and the use
of invasive ventilation in the acute phase of stroke.[8]
This case describes a patient in which the
diagnosis of bilateral HO of the hips was delayed
and highlights the importance of HO being included
in the differential diagnosis of post-stroke patients

Jt Dis Relat Surg

presenting to the Orthopedics Department with
joint pain, swelling and reduced ROM both acutely
and in the long-term following stroke. Equally,
although rare, this case reiterates that development
of HO in the non-paretic side following stroke must
be kept in mind to provide timely management of a
pathology which is difficult to treat, and can result
in ankylosis, to avoid lasting detrimental effects on
patient functionality.
Declaration of conflicting interests
The authors declared no conflicts of interest with respect to

the authorship and/or publication of this article.
Funding

The authors received no financial support for the research

and/or authorship of this article.

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