Article Review by Robin J Lansman D.O.,
Sports Injury Tutor,
British School
of Osteopathy, London
This
case control study aims to examine the correlation between Osteoarthritis in
the knee and how that has an effect on the ankle sub-talar joint, by assessing
it’s stability using an arthrometer.
The
ankle function was measured in A/P displacement as well as in inversion and
eversion. The study reports that among 27 million people in the United
States suffering from osteoarthritis, the
knee joint is the most commonly afflicted joint and it presents a large
disruption to normal activities of daily living and exercise. Disruption to the muscle function and
particularly gait cycle is commonly observed to cause a compensation both above
and below the knee joint. This is perhaps
something that Osteopaths observe as part of their normal patient assessment
and something which is taken into account frequently. There is a point when severe O/A of the knee
reaches a point when O/A of the knee produces not just bio-mechanical changes
in function of the ankle but actual arthritis at the ankle joint.
Consideration
in patient management may therefore be that ankle rehabilitation should be a
focus with any patient who is suffering from knee O/A.
This
study was careful to exclude from its’ subjects any cases where there had been
other traumas sustained in the hip area, surgical procedure or any other direct
injury to the ankle, such as fracture.
A
simple grading system was used to assess the osteoarthritic knee joints with
zero representing no O/A, and then a scoring system used between 1, 2 and 3 to
assess severity, independently assessed by two different orthopaedic
surgeons. Each patient was also assessed
for pain levels, level of stiffness and
level of functional activity for the knee joint, so that each participant in
the survey (15 subjects with O/A knee were compared with 15 healthy controls).
The
sum assessment of the knee disability was scored out of a total of 96 points in
total, to give an overall feeling of “disability” and how badly affected the
particular individual was by the O/A. The ankle sub-talar joint was assessed using
an arthrometer which basically allowed the foot to be fixed to an adjustable
plate, which then in turn could be placed under different loadings to access
the ankle function in different ranges of motion.
The
data was recorded using a digital spatial kinematic linkage using customised
software to assess the data that was collected.
The statistical analysis used on the case control design was a 2 x 2
case control design.
The study’s
results were also made interesting because each of the arthritic knee patients
also had the opposite knee and ankle tested, i.e. the side without the
O/A.
University
patients with O/A knees exhibited considerable reduction in A/P joint
displacement as well as in inversion and eversion when compared to the healthy
group.
It
should also be pointed out that all subjects used for this study, even when
they had O/A knee changes reported no actual symptoms at the ankle joint even
though on testing there was considerable restriction in the ranges mentioned in
the results.
Although
the ankle joints may not have been symptomatic and may have exhibited
dysfunction there was no X-ray taken of any of the reduced function ankle
joints to actually confirm the presence of any early stage O/A in these ankle
joints. It does seem however that other
results from another study by Tallroth et al, found significant correlation of
the severity of the O/A and deviation of the ankle joint mechanics and
alignment but in fact reported no clear relationship between ankle joint,
mal-alignment and ankle O/A, although specific studies investigating ankle O/A
exhibit similar restriction in range of movement in inversion, eversion and A/T
displacement. Moreover it seems that in
this study where there was no frank O/A of the ankle were at a lesser stage of
restriction than a population who actually suffer from ankle O/A. .
It
seems the most notable observation perhaps that Osteopathic practitioners can
bear in mind is that observing gait can indicate a considerable amount of
useful information to the clinical assessment of patients and that the varus or
valgus of the knee has a direct relationship for the normal weight bearing
function of the ankle and indeed, alterations at the hip with increased hip
flexion and abduction, as well as at the ankle, for example when climbing
stairs, are very easy to notice with a patient suffering from knee, mild to
moderate knee O/A.
At a
point in time the ankle sub-talar joint motion may not be able to compensate
for the knee pathology. A major
limitation of the study is unlike an osteopaths ‘hands-on’ approach to
examination and palpation, this study is measuring non-physiological movements
using mechanical means to produce data, when in fact there is no measurement of
natural physiologic motion, strength or function of the ankle sub-talar joint.
A key finding however, and a suggestion to clinicians is the need to
examine the ankle sub-talar joint mechanics and overall physiological motion to
help maintain patient function in cases of the O/A knee. Indeed patients may not be aware of ankle
discomfort and therefore it is possible that this is not a reported area of
symptoms that may or may not be assessed.
A
suggestion of this study would be rehabilitation and treatment for patients
with knee O/A should focus on the entire lower extremity to ensure function is
maintained at all joints, in particular the ankle joint. Additionally for them to do exercises for the
whole lower extremities should be advised for mobility, joint functionality and
possibly to prevent any changes for the ankle and the hip causing additional
problems for these patients.
On
an Osteopathic perspective it is uncertain whether Osteopathic practitioners
utilise examination procedures that will incorporate the lower limb
biomechanics in relation to spinal mechanics?
So
taking this study a step further, might be using something such as a
‘Squatting’ test, which would then actually allow the observer to assess
function between the ankle, knee, hip and through into the spinal function
giving a more global impression of function.
Perhaps something for further discussion.
The
measurement of ankle dysfunction on the opposite, supporting leg ie. the ankle
on the side which is not affected by O/A in the knee is actually also doing
more weight-bearing as a result of avoiding weight-bearing on the painful knee
side. As a result it would be expected
that although the dysfunction is measurable in the ankle on the affected side, was in fact weight-bearing compression
loading through the supporting non-arthritic side may become more dysfunctional
perhaps not when loaded using a mechanical arthrometer but indeed because of
muscle loading changes which could produce stiffness and also a change in
function in the ankle joint, something perhaps also that Osteopaths look at
with a shift of weight-bearing which is a concern.
It
is quite commonly known that when mild arthritis occurs in one knee or one
lower extremity joint it is common that the joint that wears out first is that
of the supporting leg .because the patient has been adopting an antalgic
posture tend to weight-bear even more heavily on the good side so in fact that
side is the side that becomes arthritic at an accelerating rate and often is
the knee joint surgery which needs replacement first even though it was the
matter to suffer from many symptoms.
In
the meantime, the authors suggest the results of this study indicate a need to
rehab both knees after a total knee replacement is done. The operated knee is
important but the effect of the non-operated limb can't be ignored.
Reference:
Clare E. Milner, PhD, and Mary E. O'Bryan,
BSEd. Bilateral Frontal Plane Mechanics After Unilateral Total Knee
Arthroplasty. In Archives of Physical Medicine and Rehabilitation
