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Etiologies such as trauma (patella or trochlea
fractures) dysplasia or instability are well
known risk factors.
Obesity is a classical risk factor for developping
arthritis on the lower limb, but even if
patellofemoral joint is first evolved, arthritis
may probably occur in the other compartments
sooner or later.
On the same way, genetic factors affecting
cartilage resistance may probably follow the
same evolution.
No prospective study has been undertaken to
verify that patients who have malalignment
have a greater predisposition to arthritis, but
patients who have patellofemoral arthritis often
demonstrate malalignment [8].
The greatest prevalence of chondral wear is on
the lateral facet, more commonly than on the
central or medial aspect of the patella,
suggesting that there is some degree of tilt or
malalignment in the etiology of patellofemoral
arthritis [12], theory well demonstrated by
some authors with an MRI study [10].
Conclusion
Even if patellofemoral compartment is com
monly involved in knee osteoarthritis, isolated
patellofemoral arthritis is not so rare.
Secondary patellofemoral arthitis is well known,
especially after trauma (patella fracture).
Patellofemoral dypslasia and instability are
also well documented risk factors for patello
femoral arthritis.
So primary patellofemoral osteoarthritis seems
to occur very rarely. It is hereby related to
extensor mechanism malalignment, and can
probably not be called idiopathic.
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