Course of osteoarthritis
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Course of osteoarthritisCourse of osteoarthritis
How to define osteoarthritis
There are several "levels" of osteoarthritis:anatomical, radiological and symptomatic
Many people have radiologicallyevident but asymptomaticosteoarthritis
Osteoarthritis is not necessarilysynonymous with "pain"
Thus, of 100 people aged over 65:
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Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.aspINSERM (National medical research institute) web site:http://www.inserm.fr/thematiques/circulation-metabolisme-nutrition/dossiers-d-information/arthrose
Chronic degenerative joint disease
Osteoarthritis is characterised by:
gradual destruction of the cartilage (chondrolysis)
remodelling of the subchondral bone
marginal osteophytosis
and secondary synovial inflammation
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Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.asp Sellam J, Berenbaum F. Arthrose. Rev Prat. 2011; 61: 675-686
External facet stage 4 chondral lesion. Axial image from a knee CT arthrography.
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External facet stage 4 chondral lesion. Axial image from a knee CT arthrography.
What type of osteoarthritis?
A distinction is made between: Symptomatic osteoarthritis which causes pain and functional disability
and is visible on radiographic images
Weight-bearing joint osteoarthritis (hip and knee)
Non-weight-bearing joint osteoarthritis(hand and shoulder)
Primary osteoarthritis
Secondary osteoarthritis arising subsequentto other conditions (injury, malformationor metabolic and inflammatory disorders)
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Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.asp Sellam J, Berenbaum F. Arthrose. Rev Prat. 2011; 61: 675-686
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Hip osteoarthritis surrounding the hip.
Internal and external femorotibial osteoarthritis. Knee CT-arthrography.
Rapidly destructive osteoarthritis of the shoulder, frontal image gadolinium-enhanced T1 MRI sequence
Hand and wrist MRI: SE T1-weighted, gadolinium-enhanced coronal image with fat suppression.
Oedema and fissuresCartilage lesions start with oedema which divides the collagen fibres
Superficial fissures appear
Chondrocytes try to compensate for the breakdown of the proteinsmaking up the matrix by producing growth factors
The fissures then extend down to the subchondral bone, leaving it exposed,
The number of chondrocytes drops and their pro-destructive potential increases
The subchondral bone becomes osteosclerotic at the pressure points resulting in the development of cysts
Osteophytes (attempted bone repair), also known as bony spurs,develop in marginal areas which are not under pressure
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Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.asp Sellam J, Berenbaum F. Arthrose. Rev Prat. 2011; 61: 675-686
The role of the chondrocyte
Osteoarthritis is not caused by cartilage wear and tear only
Chondrocytes "wake-up" and start to synthesise:
pro-inflammatory cytokines (IL-1, TNF)
nitrogen monoxide (NO)
pro-inflammatory lipid mediators (PGE2)
and proteolytic enzymes (metalloproteases or MPPs and aggrecanases) which cause cartilage matrix breakdown
8Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.asp Sellam J, Berenbaum F. Arthrose. Rev Prat. 2011; 61: 675-686
Imbalance between destructionand synthesis
During stress, for example when subjected to excessive mechanical load, the chondrocyte metabolism changes
The cell becomes capable of boosting synthesis of matrix components and proteolytic enzymes
and reduces release of anti-inflammatory mediators or metalloprotease inhibitors produced to halt the inflammatory process and prevent cartilage destruction (TIMP: tissue inhibitor of metalloproteinases, an IL-1 receptor antagonist)
This imbalance leads to digestion and destruction of the cartilage matrix, which is then not renewed at the same pace as new components are made
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Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.asp Sellam J, Berenbaum F. Arthrose. Rev Prat. 2011; 61: 675-686
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According to Maheu 2012
Fine balance between formationand degradation
Synoviocytes in the inflammatory synovial membraneand osteoblasts in the subchondral bone are also capable of secreting mediators, thus contributing to destructionof the cartilage
Thus, the balance between synthesis and breakdownof the cartilage matrix is upset in favour of cartilage degradation
Once fragments of the matrix are released into the synovial fluid, the inflammation continues as a resultof chronic activation of chondrocytes and the synovial membrane
Resulting in increased synthesis of pro-inflammatory mediators
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Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.asp Sellam J, Berenbaum F. Arthrose. Rev Prat. 2011; 61: 675-686
According to Piperno 2012
In sum,
12Sellam J, Berenbaum F. Arthrose. Rev Prat. 2011; 61: 675-686
Imbalance between synthesis and destruction of the cartilage matrix explaining extracellular matrix loss
D’après Sellam 2011
Pain is a measure of increasing damage
During these flares, the osteoarthritis is active and inflammatory phenomena occur
This is caused by a synovial membrane reaction: the synovial membrane's job is to cleanse the joint of the debris created by cartilage breakdown
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Knee osteoarthritis, tibial edema and synovial inflammation. FSE T2 sagittal slices.Société Française de rhumatologie website:
http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.asp
Inflammatory flares
Recent change in pain intensity: sudden increase in intensity over a few days pain at night which wakes the patient up morning stiffness lasting more than 15
minutes +/-mechanical pain as soon as any
pressure is placed on the joint.
14Sellam J, Berenbaum F. Arthrose. Rev Prat. 2011; 61: 675-686
Onset of joint effusion
Presence of signs of local inflammation: redness
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According to Sellam 2011
Does osteoarthritis always progressin flares?
The natural history of osteoarthritishas not yet been fully elucidated
It varies widely depending on the joint affected and the patient
Once diagnosed, it seems to progressin a non linear fashion
Two other patterns of progression have also been described: rapidly destructive osteoarthritis, which
causes complete destruction of the cartilage within 24 months
and slowly progressing osteoarthritis,without obvious flares
16Sellam J, Berenbaum F. Arthrose. Rev Prat. 2011; 61: 675-686
Evaluation toolsDifferent tools can be used:
Visual analogue scales for pain, functional impairment and, in the case of hand osteoarthritis, aesthetic impact
For leg osteoarthritis, maximum walking distance with and without pain and ability to complete daily tasks
Quantification of analgesic and NSAID consumption
Several indices are used for hip or knee osteoarthritis: • the Lequesne index
• the WOMAC (Western Ontario and McMaster Universities composite index)
17 Sellam J, Berenbaum F. Arthrose. Rev Prat. 2011; 61: 675-686
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According to Sellam 2012
Three progressive disease profiles
Slow progress without any obvious
Progress in flares alternating with stable periodsand periods of chrondrolysis: most common
Rapid progress: rapidly destructive osteoarthritis(total cartilage destruction in 6 to 24 months)
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In all cases, an inflammatory flare is believed to be an indication of accelerated cartilage destructionWhich is why it is so important to treat each painful flare