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Introduction
In the management of patients with patellar
instability the most important points are
obtained from the history. This will establish
the functional problems the patient is
experiencing, and the therapeutic measures
already tried. The patient’s attitude to an
operation should have been explored, as well
as key risk factors for recurrence, notably a
positive family history [1]. There are also
associated important problems, such as
hypermobility syndrome, which influence the
outcome. The association of anterior knee pain
with a poor operative result is crucial to
understand. The ideal patient is post-adolescent
with a normal body mass index, no
hypermobility, no previous operations, a
normal lower limb rotational profile, plays
regular sports, and only has intermittent
dislocations where, in between, they have a
normal functioning knee. They should ideally
live locally.
The purpose of the examination is to confirm
the diagnosis patellar instability, and to exclude
any important alternative diagnoses such as
anterior cruciate ligament rupture, medial
collateral ligament rupture, and inherited
collagen diseases such as Marfan’s and Ehlers-
Danlos syndromes.
Examination tests of
the patellofemoral
joint
There are 17 reported tests for patellofemoral
joint [2]; many are well known.
Hypermobility
Hypermobility is measured using the Beighton
score, a nine-item score. In the United Kingdom
a self-help group, the Hypermobility Syndrome
Association (HMSA) has a useful website
[http://www.hypermobility.org/].
Gait pattern
Observing a patient walking may reveal
abnormal biomechanics, notably in the foot
with pronation and persistent heel valgus
during step-off. A leg length discrepancy may
also be seen.
Lower limb alignment evaluation
With the patient standing the overall profile of
the lower limb is noted looking for femoral
anteversion, varus or valgus alignment, and
tibial torsion.
Q-angle
With the patient supine a line is drawn from the
anterior superior iliac spine to the centre of the
Clinical examination of
the patellofemoral joint
S. Donell