David R. Cooper, M.D.
www.THEKNEECENTER.com Wilkes-Barre, Pa.
Knee Joint- Anatomy
•
Is not a pure hinge
•
Ligaments are
balanced
•
Mechanism of injury
determines what
structures get
damaged
Medial meniscus
tears 10x as often
as lateral
Gaps can exist
normally behind the
meniscus
Can be read as torn
Enables us to do soft tissue imaging Does not use radiation
May not enable us to determine whether a finding
is acute or chronic
There are false positives and false negatives Watch out for degenerative tears
Meniscal Tears on the MRI
•
Cannot age tear or absolutely tell whether
it is mechanical or degenerative.
•
Any prior meniscal surgery will always
show up as an abnormality on a
subsequent MRI
•
Do not pick up a meniscal tear on an NCP
solely based upon the MRI report
Single tear
Flap displaces
anteriorly
No chondral injury
ACL is normal
Lateral meniscus is
normal
Can expect full
Only the torn
portion is removed
Remainder of
meniscus is
normal
Unlikely to retear
Inner segment
displaced into joint
blocking full
extension
Can be removed
and/or repaired
ACL intact
Good prognosis
Segment is removed No blood supply; Thus
will not heal
Good maintenance of
joint space after removal
No chondromalacia
(cartilage
Multiple small tears
Subchondral bone
is exposed
Lateral side normal
A poor result not
A trauma related meniscal tear occurs with a twist
or squat under weight bearing
Direct blow does not tear a meniscus Degenerative tears are not caused or
“aggravated” by arthritis
Arthroscopic surgery effects a full recovery in a
• Direct blow to front of
tibia does not tear ACL
• It actually loosens the
ACL
• Posterior or Lateral
stress can tear ACL
• ACL tear leads to a
• Blood vessels course along
the ACL in the synovium.
• As the ligament tears, the
blood vessels rupture.
• Large, tense effusion of
blood.
• Does not occur from a
frontal blow.
• Can be associated with
Linguini- like appearance
Hemorrhage shows it is recent Non-repairable; It must be reconstructed using a graft that does not have the same properties or placement
Do you really want a cadaver graft in your knee?
Twist or hyperextension
Knee fills with blood- can be seen by ER doc and
X-ray
No prior history of knee injury
• Full recovery is unlikely
• Working at heights is not recommended • Difficult to objectively define recovery
• Post traumatic arthritis can ensue in 25% even
with a good surgical result
• Usual restrictions are light duty with no repetitive
Visible only on an MRI
May be a precursor of traumatic arthritis High association with ACL tears
Serial MRI’s may show resolution if chronic pain
Any condition that causes inflammation of a joint
that may progress to destruction and loss of the articular cartilage.
It is a disease process of unknown etiology.
Articular surface of joints are made of protein and
water.
For some reason(s) the articular surface breaks
down exposing underlying bone.
Articular cartilege has no nerve fibers. Bone has less protection----i.e. pain.
200mg/day for 30 months.
431 overweight women 45-64yrs.
Women on doxycycline had 33% less cartilage
deterioration than those on placebo.
They also had less pain.
NO! That is a separate condition
“traumatic arthritis”
The surface of the knee is damaged, and the underlying bone is exposed
Articular surface dries
up and flakes off
Not related to trauma No nerve endings to
• Raw bone exposed • Surrounding cartilage
is normal
• No other damage seen • May be seen on an
MRI along with a bone bruise
Serial MRI’s after trauma show no more
deterioration
Subsequent weightbearing x-rays show no more
narrowing
Joint space
Knee replacements never get done on someone
who falls down at home
I’ve personally done over 600 TKR
Gradually increasing pain with inability to walk
level surfaces
Only when litigation is involved do TKR’s get
“I didn’t hurt before, but now it is killing me.”
If pain is the sole indicator, then why can’t other
conditions “aggravate” arthritis.”
No scientific or statistical evidence to link trauma
Frye, Daubert, Rule 702 Daubert- scientific studies
Frye- preponderance of opinions
Frye- may also include statistical studies or lack of
them
Worker’s comp in Pa. does not need the above to
Scientifically, Smoking increases rate of cartilage
degradation
2007 Mayo Clinic study
Male smokers had 2x loss of Art Cart compared
to nonsmokers
Get past medical records and look for prior x-rays
and statements indicating a knee replacement was considered prior to the work event
Request follow-up MRI or WB x-ray to see if
No anatomic change in Knee = No Aggravation See if prior medical records indicate prior surgery
from a different employer
May actually be post traumatic arthritis from a
Viscosupplemntation- Synvisc, hyalgan, Supartz,
Euflexxa, Orthovisc
Can be work related if indicated for traumatic
arthritis
If indicated for osteoarthritis may not be work
related.
Can be used off label for synovitis following
surgery
Be wary of bills for this- you may be picking up
Meniscal tears are usually benign, and occur with
a minor twist
ACL tears are obvious and have a definite clinical
presentation
Osteoarthritis is not related to trauma
Get how your knee injury occurred. Can make or