Imaging in osteoarthritis: conventional or modern?

Edito of 01/06/2015

In osteoarthritis, conventional radiology is used for differential diagnostic purposes, while modern imaging (MRI) is essential for studies, but is only indicated clinically in the event of complications.

In 2010, the EULAR recommended basing the diagnosis of osteoarthritis of the knee on 3 symptoms and clinical signs, without necessarily using radiological means.
In reality, standard X-rays are frequently scheduled, if for no other reason than to exclude the possibility of another joint ailment. After differential diagnosis, there are 3 other reasons to perform X-rays. Firstly to determine whether the joint damage is not due to architectural defects, particularly for the knee or hip. Next, to monitor the progression of osteoarthritic damage, that can only be ascertained in relation to a "starting examination". Finally, to reassure (and satisfy) patients who are unable to understand that they suffer from osteoarthritis without being given radiological "evidence". Thus, non-essential X-rays become desirable and wanted X-rays.

The benefits of MRI reside in the ability of magnetic resonance to highlight progressive osteoarthritis phenomena involving all joint components. Thus cartilage structure can be analysed in detail if the appropriate means are made available (sufficient MRI power, 3D image acquisition and specific sequences). Subchondral lesions can be identified in this manner. These are then correlated with pain, taking on prognostic value. In this manner, the degree of osteoarthritis severity can be quantified by measuring cartilage thickness, or by taking into consideration the damage incurred by all joint structures.
To sum up, MRI is essential for studying physiopathological mechanisms and for gaining a better understanding of the disease's natural history. It is not indicated, however, in clinical situations, except where osteoarthritis complications are suspected. In this case, the rheumatologist and radiologist should make a joint decision concerning the sequences to schedule.

Références :
Roemer FW, Eckstein F, Hayashi D, Guermazi A.
The role of imaging in osteoarthritis.
Best Pract Res Clin Rheumatol. 2014 Feb;28(1):31-60.

Zufferey P, Theumann N. 
[Imaging in osteoarthritis]. 
Rev Med Suisse. 2012 Mar 14;8(332):557-8, 560, 562-3. (article en libre accès)

Hayashi D, Guermazi A, Crema MD, Roemer FW. 
Imaging in osteoarthritis: what have we learned and where are we going? 
Minerva Med. 2011 Feb;102(1):15-32

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