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Dan Smith: On initial evaluation of a
patient with knee pain, we first inspect the patient
standing with their feet about shoulder widths apart
first looking at both knees looking for any obvious
deformity or swelling as well as the alignment of the
knees looking for any varus or valgus alignment
deformities. We then look for the feet for any pes
planus or pes cavus as well as watching them walk
briefly looking for any pronation or supination. As
you can see with our patient, he has nice normal
alignment of the knees, he has some pes planus at the
feet and some mild pronation about the ankle with
walking. The next part of the evaluation we will have
the patient in the supine position first looking for
any warmth or erythema of the knee always comparing to
the opposite knee as well. Then look at the
quadriceps musculature and have the patient contract
the quadriceps looking for tone and any muscle
atrophy. For affusion we will go down if the
suprapatellar aspect and pressing on the lateral
aspect looking for any bulging or feeling any affusion
on the medial aspect by the knee cap.
The next part of the evaluation is
palpation. This could be most easily done with the
knee in slight flexion which can be facilitated by
placing a pillow under the knee. Begin in the
front of the knee by palpating the quadriceps
muscle and tendon and then proceed to the patella
including the superior and inferior aspects of the
patella, the patellar tendon, the medial and
lateral aspects of the patella, and the fat pads on
either side of the patella tendon. Next we will
palpate the medial structures of the knee starting
with the medial collateral ligament that originates
on the medial epicondyle the femur and runs down on
to the proximal aspect of the tibia. The pes
anserine area is located approximately 3
centimeters below the medial joint line. On the
lateral aspect, we will palpate the lateral
collateral ligament as it originates on the femur
and extends out down to the fibula. Next, move
your hands behind the knee to feel for any fullness
or mass in the popliteal fossa. And finally,
palpate the bursa with a lie on the prepatellar
area, the infrapatellar area and the pes anserine
area. To assess range of motion, we will first
have the patient put their leg in full extension
looking for any hyperextension, and then going to
full flexion, typically the range of motion should
be from 0 to 135 degrees.
Speaker: To test the patient's knee strength
in the seated position, ask her to straighten her knee
against your resistance and then bend her knee against
your resistance.
Dan Smith: After you have completed
palpation, proceed to special tests of the knee to
evaluate the patella femoral joint, the ligaments, and
soft tissues. The knee will be in the extended
position. Initially we'll begin with the patellar
apprehension test to test for patellar dislocation.
Putting pressure on the medial aspect of the patella
and moving it laterally, look to the patient to see if
there is any signs of apprehension. The patella
femoral grind test, assess it's the patella femoral
joint surfaces. For this test we press down on the
patella and have the patient contract their quadriceps
muscle feeling for crepitus or noting any pain. Next
assess the integrity of the anterior cruciate
ligament. To perform the Lachman's test, flex the
knee to 20 to 30 degree, encourage the patient to
relax their hamstring musculature, firmly grasp the
femur with one hand and with the other hand behind the
proximal tibia, firmly pull, displacing the tibia upon
the femur looking for the amount of anterior
displacement and the firmness of the end point. It's
always nice to compare it to the opposite knee, and if
you get increased displacement or a soft end point,
this usually indicates an ACL injury. An alternate
way to assess the integrity of the ACL in patients
with larger legs, is to perform the Lachman's test
with your own leg underneath the femur, helping to
stabilize the femur, and again putting your hands
behind the proximal tibia and again performing a
Lachman's with pulling forward firmly looking for
anterior displacement and firmness of the end point.
The anterior drawer test is another way to assess the
integrity of the ACL. With the knee flexed at 90
degrees and sitting on the patient's foot for
stabilization, place your fingers behind the proximal
tibia and pull forward assessing the amount of
movement. The posterior drawer test is to assess the
integrity of the PCL and is performed in the same
position, now pushing posteriorly upon the anterior
aspect of the tibia checking for the amount of
posterior placement of the tibia upon the femur. The
posterior sag sign is also used to test for a PCL
tear. Place both knees in 90 degrees of flexion and
observe them laterally for posterior sagging of the
tibia of the effected knee compared to the uneffected
knee. After assessing the ACL and PCL, return the
knee to the relaxed and extended position. Now we
will assess the medial and lateral collateral
ligaments. To assess the medial collateral ligament,
we will perform the valgus stress test. In this test
we abduct the hip and flex the knee to proximally 30
degrees to remove the effect of the joint capsule on
medial knee stability. With one hand cupped
underneath the lateral aspect of the joint line and
the other hand on the anterior aspect of the ankle,
then with your distal hand, create a valgus stress on
that medial compartment assessing for the integrity of
the ligament. To assess the lateral collateral
ligament, we will perform the varus stress test.
Again, abduct the hip and flex the knee to 30 degrees.
With one hand medially, and the other hand around the
ankle and posterior aspect, provide a varus stress on
the knee and assess for ligament laxity compared to
the other side. And finally, assessing for meniscal
pathology, we want to palpate the medial and lateral
joint lines in with the knee at 90 degrees of flexion.
Find the inferior aspect of the patella, then palpate
across the medial joint line and the lateral joint
line assessing for any pain or tenderness.