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Osteoarthritis risk factorsOsteoarthritis risk factors

"Osteoarthritis, why me?"

You have told your patient that he/she has osteoarthritis. He/she is asking both you and him/herself "Why me?".

The main risk factor is age: Osteoarthritis affects only 3% of people

aged less than 45 But it affects 65% of people aged over 65.

This doesn't mean that all these are actuallyin pain, because osteoarthritis can be clinicallysilent

80% of people in the over 80 age grouphave osteoarthritis

Although age is the primary risk factor,there are many others of varying importance

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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) websitehttp://www.inserm.fr/thematiques/circulation-metabolisme-nutrition/dossiers-d-information/arthrose

The hips and knees are not the most commonly affected joints

The spine and fingers are the most commonly affected joints

It is most severe and debilitating when itaffects the knees and hips, both of whichare weight-bearing joints

While more uncommon, shoulderosteoarthritis is also very debilitating

The ankles and elbows can be affected butthis is less common and tends to occur after joint and/or bone injury

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Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.asp

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Flexor tenosynovitis in zone IV. MRI of both hands via the MCP, gadolinium-enhanced TI-weighted sequences and fat signal saturation in axial slices (prayer position). Synovitis: synovial membrane enhancement.

Internal and external femorotibial osteoarthritis. Knee CT-arthrography.

Hip-femoral osteoarthritis. Right hip arthrography, frontal image.

Cervical spine. T2 MRI.

Risk factors for osteoarthritis

Main risk factors Age Excess weight and obesity Mechanical constraints (intense

sport, some professions) Heredity Female gender, menopause Osteonecrosis Leg bone malalignement Estrogen deficiency Metabolic syndrome Advanced hip osteoarthritis caused

by spondylarthritis or rheumatoid arthritis

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Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A1_pourquoi.aspNational health insurance website:http://www.ameli-sante.fr/arthrose-de-la-hanche/facteurs-de-risques-arthrose-de-la-hanche.htmlhttp://www.ameli-sante.fr/arthrose-du-genou/facteurs-de-risque-arthrose-du-genou.htmlINSERM (National medical research institute) websitehttp://www.inserm.fr/thematiques/circulation-metabolisme-nutrition/dossiers-d-information/arthrose

Other risk factors Injury: cruciate ligament rupture,

meniscectomy (surgical removal of meniscus)

Metabolic diseases (chondro-calcinosis, genetic hemochromatosis)

Infectious diseases involving the bone Rheumatoid arthritis sequellae

Weight and osteoarthritis: a complicated relationship

In overweight patients and especially in the obese, the joints are exposed to mechanical constraints which tend to promote the development of osteoarthritis, particularly in the knees

However: Obesity has a "dose-related" effect: the risk of knee osteoarthritis

increases by 15% for every point increase in the BMI. The risk of knee osteoarthritis therefore increases with weight

It is important to note that finger joint osteoarthritis is more common in obese patients!

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Body Mass Index calculation (BMI)

Overweight if BMI = 25-29.9 kg/m2

Obesity > 30 kg/m2

Morbid obesity > 40 kg/m2

Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A1_pourquoi.aspSellam J, Berenbaum F. Arthrose et obésité. Rev Prat 2012;;62::621-624.

When mechanical constraint promotes osteoarthritis

Mechanical constraint is a risk factor for osteoarthritis, particularly in the knee

The knee is a complex joint and weight must be evenly distributed and not excessive. The risk factors for knee osteoarthritis are therefore:

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Being overweight or, especially, obese leg bone malalignement (genu varum [bow legs] and genu valgum

[knock-knees]) Knee instability caused by ligament rupture (cruciate ligaments) Surgical removal of a meniscus (meniscectomy) Repeatedly carrying excessive loads

INSERM (National medical research institute) websitehttp://www.inserm.fr/thematiques/circulation-metabolisme-nutrition/dossiers-d-information/arthrose

Other risk factors for osteoarthritis include an untreatedsprain or a joint fracture

Knee osteoarthritis, injury and surgery

There are two forms of injury which play a particularly important role in the onset of knee osteoarthritis : Sprain with ligament tear, creating knee instability, Meniscus damage

8 Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.asp

Cruciate ligament surgery will not totally prevent the riskof osteoarthritis after these types of injury: Experience shows that while surgery reduces this risk,

it nonetheless remains high

Conversely, meniscus removal is a major risk factorfor osteoarthritis: Studies have reported that 5 to 10 years after meniscectomy, the

incidence of osteoarthritis was much higher in the operated knee (21% versus 5% on the non-operated side). Furthermore, meniscectomy is an excellent model of induced osteoarthritis in animals

Patellofemoral knee osteoarthritis.

Physical exercise and osteoarthritis

When not practiced to excess, physical exercise is not a risk factor for osteoarthritis

The risk factors are considered to be:

Top-level sports with the risk of injury: footballand rugby for the knees

Repetitive excessive load-bearing

Repeated microtrauma (workers regularly usinga jack hammer: elbow osteoarthritis)

Some professions placing excessive pressure on the knees (tiler, carpet-fitter, mason, painter and decorator, gardener, etc.)

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Société Française de rhumatologie website: http://www.rhumatologie.asso.fr/04-Rhumatismes/grandes-maladies/0B-dossier-arthrose/A0_definition.asp

Heredity and osteoarthritis

People with a parent or sibling who has osteoarthritis are at higher risk of developing the disorder

The proof:

there are families in which the proportion of adultsaged over 50 with osteoarthritis is much higher thanin the general population

concordance of osteoarthritis is more commonin identical than non-identical twins

however, these genetic factors have been demonstrated mainly for hip or hand osteoarthritis.

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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) websitehttp://www.inserm.fr/thematiques/circulation-metabolisme-nutrition/dossiers-d-information/arthrose

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MRI of both hands and wrists: SE T1 sagittal images.

Hip osteoarthritis surrounding the hip.

Other risk factors

Gender and hormonal status: post-menopausal women are at higher risk of hip, knee or hand osteoarthritis than men of a similar age

Differences in long bone length increase the risk of hip osteoarthritis but it may also affects subjects aged less than 50

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http://www.ameli-sante.fr/arthrose-de-la-hanche/facteurs-de-risques-arthrose-de-la-hanche.htmlhttp://www.ameli-sante.fr/arthrose-du-genou/facteurs-de-risque-arthrose-du-genou.html

Conclusion

Osteoarthritis is a strongly age-associated condition

The most commonly affected joints are the spine (back bone) and hands

Osteoarthritis is most debilitating when it affects the hip or knee

Overweight patients are at higher the risk of developing osteoarthritis, particularly in the knees

Normal physical exercise is not a risk factor (if no injuries are sustained)

Post-menopausal women are at higher risk of hip or knee osteoarthritis than men of a similar age

An unstable knee and leg malalignement are risk factors for the development of knee osteoarthritis

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Lumbar canal stenosis, posterior lumbar facet joint osteoarthritis, sagittal image of lumbar spine.

Hand and wrist MRI: coronal image, SE T1 sequence with suppression of fat signal and injection of gadolinium.

Primary osteoarthritis,CT-arthrography.

Advanced internal femorotibial knee

osteoarthritis. MRI T2 images.