I just got this sent to me from the SORSI group, and I thought I'd
pass it along. Very good information.

--Adrian


Sacroiliac Manipulation And Anterior Knee Pain
SOURCE: Suter, Esther, PhD, McMorland, G, DC, Herzog, W, PhD and
Bray, R, MD.
Decrease in Quadriceps Inhibition After Sacroiliac Joint Manipulation in
Patients with Anterior Knee Pain. JMPT, Volume 22, Number 3, March/
April 1999,
pages 149 - 153
ABSTRACT: Anterior knee pain is often associated with weakness and
inhibition
of the knee extensors, particularly the vastus medialis, resulting in
imbalance in the activation patterns of the knee extensor groups,
thus accelerating
patellofemoral pain. Treatment protocols have included physical
therapy/rehabilitation programs and even surgical intervention.
However, the lack of full
recovery has been related to strength deficits and the inability to
achieve full
recovery of the affected structures, often associated with persistent
muscular
inhibition. It has been suggested that muscular inhibition needs to be
overcome before significant improvement in muscle strength and
function can be
achieved. This pilot study was performed to establish whether
quadriceps inhibition
in patients with anterior knee pain was affected by sacroiliac joint
manipulation.

18 subjects with chief complaints of anterior knee pain participated
in this
study. Four had bilateral anterior knee pain, six had knee surgery
and 11 had
received physical therapy treatment. Before and after sacroiliac
manipulation,
torque, muscle inhibition, and muscle activation for the knee extensor
muscles were measured during isometric contractions using a Cybex
dynamometer,
muscle stimulation and electromyography. The knee extensors were
measured
bilaterally. Muscular inhibition was measured at 10 - 15% higher than
normal subject
comparison. Sacroiliac evaluation was performed with active forward
bending,
motion palpation and the sit up test for sacroiliac dysfunction. A
sacroiliac
joint was deemed symptomatic if pain was present over the posterior
superior
iliac spine and if provocation tests, such as Yeoman's, sacral
compression, and
Patrick's FABER test, exacerbated discomfort over the PSIS. 12 of the
patients
demonstrated a symptomatic sacroiliac dysfunction whereas 6
demonstrated an
asymptomatic sacroiliac dysfunction. The manipulation consisted of a
high
velocity, low amplitude thrust to the sacroiliac joint ipsilateral to
the side of
anterior knee pain. For those with bilateral anterior knee pain, the
side of
greatest subjective complaint was treated.

After correction of the sacroiliac dysfunction, an increase in knee
extensor
torque and a decreased in muscle inhibition were observed in the
involved leg.
Electromyographic activation of the vastus medialis was higher in the
involved leg post manipulation.
Evidence suggests that the success of conservative treatment in
restoring
muscle function is limited in the presence of severe muscle
inhibition. This is
consistent with this study as most of the subjects had a history of
incomplete
recovery following surgery or physical therapy. This study
demonstrates that
chiropractic manipulation may be an alternative or as an adjunct in the
treatment of anterior knee pain.

COMMENTS: This is a very interesting pilot study that will hopefully
lead to
further research. The relatively small size of this study must be
expanded
upon and future studies should be randomized, and double blinded.
However,
considering the incomplete recovery in many patients whom undergo
surgical and
physical medicine treatments, this study offers an interesting
hypothesis as to
why. There are two issues that present themselves when reviewing this
data. The
first is neurological, the later, biomechanical, but both have clinical
ramifications.

The inhibition of the extensors of the knees is a neurological
expression of
a reduction of excitatory postsynaptic potentials, and/or an increase
in the
amount of inhibitory postsynaptic potentials affecting the anterior
horn cells
of the spinal column. A review of the simple reflex arc is
appropriate at this
point, which will lead us to therapeutic considerations.

For example, when eliciting a simple reflex, the tendon of the
agonist muscle
is struck with a reflex hammer. This will produce the following
events at the
spinal cord level. An excitatory postsynaptic potential occurs
monosynaptically at the agonist muscle and a inhibitory postsynaptic
potential (via and
interneuron) occurs at the antagonist muscle. From review of this
arc, one would
conclude that electrical muscle stimulation applied to the knee
extensors
reduces inhibition of this area by creating excitatory postsynaptic
potentials at
anterior horn cells that affect the quadriceps muscle. From the
results of the
manipulation causing reduction in the inhibition of the knee extensors,
further investigation as to whether stimulation of mechanoreceptors
of the
sacroiliac joint are specific to creating excitatory post synaptic
potentials of the
knee extensors would be of interest. The actual position of the lower
extremity
during the manipulation could have a dramatic effect as well, in that
it would
dramatically alter the manner in which fast stretch is applied to the
knee
extensors themselves.

Biomechanically, alterations in gait cycle can certainly lead to
sacroiliac
dysfunction. This, along with the muscular weakness that commonly is
associated
with joint injuries, can account for a majority of the increased
muscular
inhibition of the knee extensors. A mechanical consideration beyond the
neurological inhibition needs to be identified, particularly if the
clinician feels it
may have caused the knee pain. Appropriate biomechanical analysis of
the lower
extremity should be performed, for example, to determine if an
orthotic is
appropriate, and to help determine what rehabilitative exercises are
appropriate.
In regard to anterior knee pain and the sacroiliac joint:
a. Anterior knee pain is often associated with inhibition of the vastus
medialis.
b. Sacroiliac manipulation can produce excitatory post synaptic
potential of
dorsal horn cells of the spinal cord to affect knee extensors.
c. Muscular inhibition may have to be overcome before more functional
strength gains can occur.
d. Both A and C.

Brian Mouch DC
6010 Wooster Pike
Cincinnati, Ohio 45227
513-271-4849