How to Properly Diagnose Sports-Related Knee Injuries

as with all joints you'll start your

examination with inspection I look at

the knee initially to make sure there's

no loss of muscle tone and bulk and any

swelling or a discoloration the first

thing that I will do I'll have the

patient do a quad set and quad sets are

important because it is an important

part of rehabilitation but it's also an

important part in the diagnostic

evaluation because if the patient can't

do a full quad set because of pain or

swelling then you immediately know that

with your physical therapist you're

going to have to design therapeutic

regimen which is going to get their quad

back the quad is the principal medial

dynamic stabilizer of the patella if

they can't get that muscle firm and

maintain its integrity strength

endurance then they're gonna have

trouble with your knee you want to look

for is bulk comparing the injured side

to the uninjured side and you want to

then palpate looking for tone when you

are looking for an effusion of the knee

what I try to do as I will milk the

fluid down from the suprapatellar area

I'll push it out of the medial joint

space into the lateral and then I

quickly flip my fingers and press

lateral to medial if you see a fluid

wave if they have an effusion now there

is a specific test called the

apprehension test if patients have

either subluxed or dislocated the

patella when you have them down and you

try to displace it laterally they'll

tighten up and they won't let you do it

they'll be very uncomfortable with that

ie the apprehension test patients who

have acute or chronic knee pain who

won't let you do this because they

complain of medial knee pain you have to

be suspicious that they're chronically

subluxation patella or in fact maybe

have dislocated or patella the femoral

groove when you displace them medially

you now have push the patella the medial

side of the patella so it's easy to

palpate on this side and when you

palpate there you can if you reproduce

their pain there

they have patellofemoral dysfunction

manifest his pain on the medial side of

the patella there's a specific test is

called the Thomas test for hip flexor

flexibility and specifically if patients

have tight hip flexors they can be at

risk for patellofemoral pain the other

tests we assess for lower extremity

flexibility routinely is hamstring

flexibility and we recorded as the

popliteal angle the popliteal angle is

usually 10 or 15 degrees greater in

women that it is in men and the key that

you're looking for is loss of

flexibility and hamstrings as well as

asymmetry in patients who have an

injured extremity and have lost

flexibility on that side you know you

have to improve that flexibility in

order for them to rehabilitate to get

fully back to where they were the last

test for flexibility is the Ober test

which tests for iliotibial band

flexibility iliotibial band tendonitis

is a very common chronic tendinitis and

you test for the tightness of the

iliotibial band where if it is

inflexible or if you have a positive

Ober test when you do a specific

maneuver then they will stay up and

rather than flopping down let me talk a

little bit about testing cartilage shows

in these specifically I'm gonna on this

model take the patellar tendon away to

give you a good look at a model medial

meniscus of the lateral meniscus and

also in this view you'll notice that the

anterior cruciate ligament has been cut

away to allow better visualization of

the inside of the joint when I do tests

for the cartilage there's a couple of

specific tests I do one you'll notice

the test called the bounce home test I

start by holding the patient's heel and

literally bringing them up into

extension patients who have significant

cartilaginous tears meniscal tears will

not necessarily let you go into full

extension so if a patient can come into

full extension the so-called bounce home

tests that suggest to you that if they

have a cartilage tear it may not be a

big tear if they stop right about here

then maybe you have a cartilage tear and

you need to investigate it further you

want to try to palpate along the medial

and lateral joint lines what you do when

you palpate you identify the distal

femoral condyle

you identify the tibial plateau and

right in there you'll be able to feel an

angle as you walk your finger along this

rim here to this angle any specific

tenderness here that's very discrete

suggests in the context of the

appropriate history suggest that you

have a cartilage tear on the medial

meniscus and then when you come to the

lateral joint line same thing you find

this angle here between the lateral

femoral condyle the tibial plateau and

that right there is the meniscus you

don't necessarily feel it as a discrete

entity but over time you will come to

appreciate exactly what you're feeling

underneath the skin is the cartilage the

next thing we do is a test called a

McMurray test and McMurray test is to

test for cartilage tears what I'm trying

to do is identify tears along the

meniscal rim here either of the medial

meniscus or the lateral meniscus so what

you want to do is you want to create

lots of angles which the cartilage

interfaces with the femur and see if you

can pick up some clunk or a click or a

patient tells you that's uncomfortable

and so the way I do the examination is

have the patient lay on their back and I

initially go into full flexion of the

knee full extension and then remember

this is the right knee model I will

externally rotate the tibia and I try to

hold it I hold the hip in neutral go

into flexion and extension and then I

internally rotate the tibia go into full

flexion and extension then what I try to

do is an exam called the modified

McMurray exam when I do that I

externally rotate the whole hip and that

puts a little bit more if this is the

right eye rotated out this way it puts a

little bit more pressure on the medial

cartilage but I'll do the same basic

techniques externally rotate the tibia

full flexion and extension internally

rotate the tibia full flexion and


and then what I do is I take the hip and

I put it into internal rotation so now

the hip is going pointing internally but

I do the same examinations and here as

you might imagine you're putting a

little bit more pressure on the lateral

meniscus I'll do the same techniques

internally rotate the tibia flexion and

extension externally rotate the tibia

flexion and extension when you test for

the medial collateral ligament you have

the patient's knee at zero degrees of

flexion full extension and you initially

put a valgus stress on them so you try

to open them up that way if they have

instability that is they open up here or

if that reproduces their pain and they

give you a history which is consistent

with medial collateral ligament tear

then you've made your diagnosis when I

then we'll do is I'll open them up to

about 30 degrees of flexion and repeat

the examination with valgus stress and

you're looking for the same thing there

now I'll flip the model over and show

how one dem tries to assess the lateral

collateral ligament demonstrated here

zero degrees of flexion you try to open

them up and then thirty degrees of

flexion you try to open them up rotate


yeah okay anterior cruciate ligament is

assessed using four different techniques

there's the anterior drawer technique

the anterior drawer technique is simple

to do it's not as sensitive but it's

pretty specific so the patients have a

history consistent with anterior

cruciate ligament injury they were

weight-bearing and they twisted and they

felt something pop if they have a

positive anterior drawer test which is

manifest as increased laxity on the

injured side compared to the uninjured

side then they have an anterior cruciate

ligament tear however if it's negative

that doesn't mean they haven't torn the

anterior cruciate ligament then you have

to do some other specific testing the

tests that I do are the Lockman maneuver

and in the Lockman maneuver you look for

trying to translate the tibia anteriorly

relative to the to the femur and the

important thing is a symmetry a patient

may feel a little bit lacks on the

injured side but if there really lacks

compared to the uninjured side then you

have that's a supporting evidence of the

ACL injury the other technique is the

modified Lachman which for me is much

easier for larger patients football

players and track and field athletes etc

it allows me to get my hands around the

tibia a little bit better and I think do

a more sensitive exam and and again

you're looking for increased laxity on

that testing compared to the uninjured

side the final test is the pivot shift

and this is probably the most difficult

but probably the most sensitive of all

the tests you lean into the long axis of

the leg the injured leg you internally

rotate the hip a little bit and you

provide a gentle valgus stress so you're

pressing in a valgus fashion on the knee

you started full extension and then you

try to flex and then you take from

flexion down into extension and what

you're feeling for there is in a knee

that doesn't have a sufficient or an

intact anterior cruciate ligament you

feel the tibia and the femur slipping

and sliding on one another and you feel

the injured side you feel the uninjured

side now the nature of the pivot shift

is such that if a patient has an

insufficient anterior cruciate ligament

you do that a couple of times they

really don't like it so you generally

get one shot at it

now one of the exam techniques assessing

for posterior cruciate ligament

sprains or insufficiency and what you do

there is you have the patient lie supine

and you have them flex their hips to 45

degrees and their knees to 90 degrees

and if their posterior cruciate ligament

has been torn will happen is to take

tibia will sag posterior lis down

towards the table