Indian Journal of Nuclear Medicine
Home | About IJNM | Search | Current Issue | Past Issues | Instructions | Ahead of Print | Online submissionLogin 
Indian Journal of Nuclear Medicine
  Editorial Board | Subscribe | Advertise | Contact
Users Online: 135 Print this page  Email this page Small font size Default font size Increase font size


 
 Table of Contents     
INTERESTING IMAGES
Year : 2016  |  Volume : 31  |  Issue : 2  |  Page : 156-157  

Femoroacetabular impingement mimicking avascular osteonecrosis on bone scintigraphy


1 Department of Nuclear Medicine, Caceres Hospital, Cáceres, Spain
2 Department of Nuclear Medicine, University Medical Center, Orense, Spain

Date of Web Publication9-Mar-2016

Correspondence Address:
Juan Pablo Suarez
Department of Nuclear Medicine, "San Pedro de Alcántara" Hospital, Cáceres, Ave. Pablo Naranjo S/N 10003, Cáceres
Spain
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-3919.178337

Rights and Permissions
   Abstract 

Femoroacetabular impingement (FAI) is a structural abnormality of proximal femur and/or acetabulum. It has been recently described, and there are limited reports in nuclear medicine literature because bone scintigraphy is not listed in its diagnostic protocol, but it should be included on differential diagnosis when evaluating patients, with hip-related symptoms because it may be misinterpreted as degenerative changes or avascular necrosis, and its early treatment avoid progression to osteoarthritis. We describe the case of a male who suffered from hip pain. Bone planar scintigraphic appearance mimicked avascular necrosis, but single photon emission computed tomography (CT) imaging and CT examination confirmed the diagnosis of FAI.

Keywords: Avascular osteonecrosis, bone scintigraphy, femoroacetabular impingement, hip


How to cite this article:
Suarez JP, Domínguez ML, Nogareda Z, Gómez MA, Muñoz J. Femoroacetabular impingement mimicking avascular osteonecrosis on bone scintigraphy. Indian J Nucl Med 2016;31:156-7

How to cite this URL:
Suarez JP, Domínguez ML, Nogareda Z, Gómez MA, Muñoz J. Femoroacetabular impingement mimicking avascular osteonecrosis on bone scintigraphy. Indian J Nucl Med [serial online] 2016 [cited 2019 Sep 18];31:156-7. Available from: http://www.ijnm.in/text.asp?2016/31/2/156/178337

A 42-year-old man presented with one year history of progressive left hip pain resulting in restricted mobility in flexion and internal rotation. There was no history of trauma, and a radiograph of the left hip demonstrated a cortical bump in the femoral neck and a slight narrowing of the joint space. Tc-99m hydroxymethylenediphosphonate bone scan [Figure 1] anterior and posterior planar images (a) demonstrated an incomplete "donut" of increased activity surrounding a relatively "cold" left femoral head suggesting the presence of avascular necrosis. Single photon emission computed tomography (SPECT) of the pelvis was performed to further evaluate this area (b). Correlation between scintigraphic uptakes and radiological findings on pelvic CT scan is shown at selected coronal slices of CT (c) and SPECT study (d) and radiograph (e) of left hip. The increased tracer uptakes were located at the lateral bump on the left head-neck junction (thick arrows), in the superolateral and inferointernal aspect of the acetabulum related to degeneration (thin arrows) and in an osteophyte in the inferior aspect of the femoral head (heads of arrows). CT axial slices of left femoral head (f) did not show typical findings of avascular necrosis (low-density areas or clumping and distortion of trabeculae), so all findings suggested the diagnosis of femoroacetabular impingement (FAI) of the cam type.

FAI is characterized by a pathologic contact during hip joint motion between skeletal prominences of the acetabulum and the femur. [1] Two types of impingement are distinguished [Figure 2]a: Cam, which is associated with reduced femoral head-neck offset (more common in young men) and pincer, present with acetabular retroversion (more common in middle-aged women), with the majority of the patients having both (mixed type). [2]
Figure 1: Anterior and posterior (a) planar images with Tc-99m hydroxymethylene diphosphonate (HMDP) demonstrated abnormal uptake in the left femoral head. Axial, coronal and sagittal slices of SPECT of the pelvis (b) allowed a better anatomical location. Correlation between scintigraphic uptakes and radiological findings is shown at selected coronal slices of CT (c) and SPECT study (d), and radiograph (e) of left hip. CT axial slices of left femoral head (f) did not suggest the presence of avascular necrosis

Click here to view
Figure 2: (a) Graphical illustration of the types of femoro-acetabular impingement. The shaded areas indicate the sites of abnormality. (b) Volumetric imaging of pelvis showing pathological uptake around left head-neck junction (arrows)

Click here to view


Although bone scintigraphy is not included in the diagnostic protocol of FAI, [2] it should be included on the differential diagnosis when evaluating patients with hip-related symptoms. The scintigraphic features reflect the pattern of remodeling that occurs at the sites of impingement [3] (increased focal uptake involving the anterosuperior aspect of the acetabulum and/or increased tracer uptake along the anterosuperior aspect of the femoral neck), with normal blood flow images. [4],[5] Positive bone scintigraphy can be an early indicator of intraarticular cartilage damage that may present before the onset of symptoms. [4] These findings can be misdiagnosed as degenerative changes [5] to avascular necrosis, [3] so it is very important to add tomographic images, preferably with SPECT-CT for anatomic information because early surgical correction can reduce the progression of osteoarthritis. [6] Surgery eliminates the pathomechanics of structural deformities: Cam impingement can be treated with anterolateral osteoplasty, often arthroscopically whereas pincer-type impingement can be treated with periacetabularosteotomy, so these treatments will ultimately reduce the necessity of hip replacements. [5]

We would like to remark that volumetric imaging of our case [Figure 2]b showed pathological uptake around left head-neck junction (arrows). This finding could suggest that real structure of FAI anatomic abnormality is not restricted to a focal defect, but reach the whole femoral head-neck junction although this finding has not been described in the literature to date.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

1.
Beck M, Kalhor M, Leunig M, Ganz R. Hip morphology influences the pattern of damage to the acetabular cartilage: Femoroacetabular impingement as a cause of early osteoarthritis of the hip. J Bone Joint Surg Br 2005;87:1012-8.  Back to cited text no. 1
    
2.
Amanatullah DF, Antkowiak T, Pillay K, Patel J, Refaat M, Toupadakis CA, et al. Femoroacetabular impingement: Current concepts in diagnosis and treatment. Orthopedics 2015;38:185-99.  Back to cited text no. 2
[PUBMED]    
3.
Lee A, Emmett L, Van der Wall H, Kannangara S, Mansberg R, Fogelman I. SPECT/CT of femeroacetabular impingement. Clin Nucl Med 2008;33:757-62.  Back to cited text no. 3
    
4.
Matar WY, May O, Raymond F, Beaulé PE. Bone scintigraphy in femoroacetabular impingement: A preliminary report. Clin Orthop Relat Res 2009;467:676-81.  Back to cited text no. 4
    
5.
Mulholland NJ, Gnanasegaran G, Mohan HK, Vijayanathan S, Clarke SE, Fogelman I. Recognition of the femoroacetabular impingement syndrome on MDP SPECT CT. Clin Nucl Med 2008;33:125-7.  Back to cited text no. 5
    
6.
Ganz R, Parvizi J, Beck M, Leunig M, Nötzli H, Siebenrock KA. Femoroacetabular impingement: A cause for osteoarthritis of the hip. Clin Orthop Relat Res 2003;417:112-20.  Back to cited text no. 6
    


    Figures

  [Figure 1], [Figure 2]



 

Top
  
 
  Search
 
  
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
    Abstract
    References
    Article Figures

 Article Access Statistics
    Viewed808    
    Printed9    
    Emailed0    
    PDF Downloaded80    
    Comments [Add]    

Recommend this journal