Kinematic study of the temporomandibular joint in normal subjects and patients following unilateral temporomandibular joint arthrotomy with metal fossa-eminence partial joint replacement


Yoon, H-Joong.; Baltali, E.; Zhao, K.D.; Rebellato, J.; Kademani, D.; An, K-Nan.; Keller, E.E.

Journal of Oral and Maxillofacial Surgery 65(8): 1569-1576

2007


The primary purpose of this study is to quantify the kinematics of the temporomandibular joint (TMJ) in patients following unilateral TMJ arthrotomy with metal fossa-eminence partial joint replacement and compare them with TMJ kinematics of healthy individuals. Fourteen healthy volunteers and 13 female surgical patients (minimum 4 years postoperative) participated in this study. An electromagnetic tracking device was used to record the kinematics of the mandible relative to temporal bone during opening-closing, protrusive, and lateral movements. The mean linear distance (LD) traveled by condyles was compared between operated and normal subjects. Patients responded with statistically significant improvement in pain and jaw function questions. Mean satisfaction with the surgical result was 25.7 on a scale of 1 to 30. The LD measured for condyles during all 4 movements showed similar measurements. However, operated and unoperated condyles showed statistically significant motion values during opening and protrusive motion from each other and from normal subjects. In addition, contralateral condyles during lateral motion showed statistically significant values in operated, unoperated, and normal condyles. The results of this study suggest that the surgical reconstruction of the TMJ with partial joint replacement provided highly significant clinical improvement. Moreover, condyle and incisor kinematics were preserved to a significant amount as compared with the normal group. The difference in kinematic measurements between the operated and unoperated condyle was significant and secondary to previous joint disease and previous surgical intervention. These results should be evaluated by prospective studies in pre- and postsurgical patients.

Kinematic
Study
of
the
Temporomandibular
Joint
in
Normal
Subjects
and
Patients
Following
Unilateral
Temporomandibular
Joint
Arthrotomy
With
Metal
Fossa-Eminence
Partial
Joint
Replacement
Hyunjoong
Yoon,
DDS,
PhD,*
Evre
Baltali,
DDS,
f
Kristin
D.
Zhao,
MA,#
Joe
Rebellato,
DDS,f
Deepak
Kademani,
DMD,
MD,11
Kai-Nan
An,
PhD,
fl
and
Eugene
E.
Keller,
DDS,
MSD#
Purpose:
The
primary
purpose
of
this
study
is
to
quantify
the
kinematics
of
the
temporomandibular
joint
(TMJ)
in
patients
following
unilateral
TMJ
arthrotomy
with
metal
fossa-eminence
partial
joint
replacement
and
compare
them
with
TMJ
kinematics
of
healthy
individuals.
Materials
and
Methods:
Fourteen
healthy
volunteers
and
13
female
surgical
patients
(minimum
4
years
postoperative)
participated
in
this
study.
An
electromagnetic
tracking
device
was
used
to
record
the
kinematics
of
the
mandible
relative
to
temporal
bone
during
opening-closing,
protrusive,
and
lateral
movements.
The
mean
linear
distance
(LD)
traveled
by
condyles
was
compared
between
operated
and
normal
subjects.
Results:
Patients
responded
with
statistically
significant
improvement
in
pain
and
jaw
function
ques-
tions.
Mean
satisfaction
with
the
surgical
result
was
25.7
on
a
scale
of
1
to
30.
The
LD
measured
for
condyles
during
all
4
movements
showed
similar
measurements.
However,
operated
and
unoperated
condyles
showed
statistically
significant
motion
values
during
opening
and
protrusive
motion
from
each
other
and
from
normal
subjects.
In
addition,
contralateral
condyles
during
lateral
motion
showed
statistically
significant
values
in
operated,
unoperated,
and
normal
condyles.
Conclusion:
The
results
of
this
study
suggest
that
the
surgical
reconstruction
of
the
TMJ
with
partial
joint
replacement
provided
highly
significant
clinical
improvement.
Moreover,
condyle
and
incisor
kinematics
were
preserved
to
a
significant
amount
as
compared
with
the
normal
group.
The
difference
in
kinematic
measurements
between
the
operated
and
unoperated
condyle
was
significant
and
secondary
to
previous
joint
disease
and
previous
surgical
intervention.
These
results
should
be
evaluated
by
prospective
studies
in
pre-
and
postsurgical
patients.
©
2007
American
Association
of
Oral
and
Maxillofacial
Surgeons
J
Oral
Maxillofac
Surg
65:1569-1576,
2007
*Associate
Professor,
Department
of
Oral
and
Maxillofacial
Sur-
gery,
St.
Mary's
Hospital,
Catholic
University
of
Korea,
Seoul,
South
Korea;
Formerly
Research
Fellow,
Division
of
Oral
and
Maxillofacial
Surgery,
Department
of
Surgery,
Mayo
Clinic,
Rochester,
MN.
tResearch
Fellow,
Division
of
Oral
and
Maxillofacial
Surgery,
Department
of
Surgery,
Mayo
Clinic,
Rochester,
MN;
Resident,
Department
of
Oral
and
Maxillofacial
Surgery,
Faculty
of
Dentistry,
Selcuk
University,
Konya,
Turkey.
*Engineer,
Biomechanics
Laboratory,
Division
of
Orthopedic
Re-
search,
Mayo
Clinic,
Rochester,
MN.
pormer
Consultant,
Division
of
Orthodontics,
Department
of
Dental
Specialties,
Mayo
Clinic,
Rochester,
MN.
IlAssistant
Professor,
Division
of
Oral
and
Maxillofacial
Surgery,
Department
of
Surgery,
Mayo
Clinic,
Rochester,
MN.
¶Professor
and
Director,
Biomechanics
Laboratory,
Division
of
Orthopedic
Research,
Mayo
Clinic,
Rochester,
MN.
*Professor
and
Chair,
Division
of
Oral
and
Maxillofacial
Surgery,
Department
of
Surgery,
Mayo
Clinic,
Rochester,
MN.
This
research
project
was
performed
at
and
supported
by
the
Division
of
Oral
and
Maxillofacial
Surgery,
Department
of
Surgery
and
Biomechanics
Laboratory,
Division
of
Orthopedic
Research,
Mayo
Clinic,
Rochester,
MN.
Address
correspondence
and
reprint
requests
to
Dr
Keller:
Oral
and
Maxillofacial
Surgery,
Mayo
Clinic
College
of
Medicine,
Roch-
ester,
MN
55902;
e-mail:
keller.eugene@mayo.edu
©
2007
American
Association
of
Oral
and
Maxillofacial
Surgeons
0278-2391/07/6508-0021$32.00/0
doi:10.10164joms.2006.10.009
1569
1570
NORMAL
VERSUS
POSTSURGICAL
TMJ
IUNEMATICS
In
most
temporomandibular
joint
amp
patients,
the
symptoms
are
mild
and
cyclic
with
varying
degrees
of
pain
and
restricted
movement.
These
patients
can
often
be
managed
medically
with
nonsteroidal
anti-
inflammatory
drugs,
physiotherapy,
and
other
forms
of
nonsurgical
therapy.
In
patients
with
progressive
disease,
the
meniscus
and
interpositional
soft
tissues
within
the
TMJ
can
be
displaced
or
perforated,
allow-
ing
for
bone
on
bone
contact
between
the
mandibular
condyle
and
glenoid
fossa.
Functional
loading
leads
to
degeneration
of
the
osseous
articular
surfaces,
subar-
ticular
bone
erosion,
and
sclerosis
of
the
underlying
cancellous
bone.
This
condition
is
classified
as
degen-
erative
joint
disease
or
osteoarthritis.
Further
progres-
sion
can
lead
to
fibrous/osseous
ankylosis.
These
pa-
tients
often
require
surgical
intervention
and
fall
into
the
hands
of
oral
and
maxillofacial
surgeons.
1
The
indications
for
TMJ
surgery
are
rigorous
and
his-
torically
thought
of
as
the
"last
resort,"
with
only
1%
or
less
of
all
patients
referred
with
a
diagnosis
of
temporo-
mandibular
disorder
requiring
surgery.
Widmark
2
con-
cluded
that
unsuccessful
conservative
treatment
should
not
exceed
3
to
6
months,
and
patients
with
fibro
or
bony
ankylosis
should
be
treated
surgically
without
de-
lay.
We
believe
a
high
percentage
of
osteoarthritic
pa-
tients
with
bone
on
bone
contact
and
persistent
pain
should
also
be
treated
surgically
without
delay.
Many
techniques
for
the
reconstruction
of
the
osseous
struc-
ture
(fossa,
eminence,
and
condyle)
and/or
disc
of
TMJ
have
been
described
and
include
both
autogenous,
allo-
plastic,
and
partial/total
joint
materials
and
systems.
1
'
3
There
is
controversy
on
the
indications
and
tech-
niques
for
reconstruction
of
the
TMJ.
Before
1980,
alloplastic
joint
replacement
(hemiarthroplasty/par-
tial
joint
replacement)
was
performed
mainly
after
ablative
surgery
and
in
cases
of
bony
ankylosis,
trauma,
or
severe
degenerative
joint
disease.
In
the
mid
to
late
1980s,
as
many
patients
began
to
fail
initial
medical
and
surgical
treatment,
partial
or
total
TMJ
prosthetic
reconstruction
was
performed
as
salvage
therapy.
4
Recently,
Wolford
et
al
5
described
selection
criteria
for
prosthetic
TMJ
reconstruction
as:
1)
mul-
tiply
operated,
2)
previous
failed
alloplastic
implants,
3)
osteoarthritis,
4)
inflammatory
or
resorptive
arthri-
tis,
5)
connective
tissue
or
autoimmune
disease,
6)
ankylosis,
and
7)
absent
or
deformed
structures.
Mercuri
6
'
7
reported
the
advantages
of
alloplastic
TMJ
reconstruction
as:
1)
physical
therapy
can
begin
immediately,
2)
no
need
for
a
secondary
donor
site,
3)
decreased
surgery
time,
and
4)
ability
to
mimic
nor-
mal
anatomy.
The
stated
disadvantages
were:
1)
cost
of
the
prosthetic
device,
2)
alloplastic
material
wear
and
failure,
3)
long-term
stability,
and
4)
lack
of
ad-
justment
in
a
growing
patient.
We
have
used
the
Co-Cr-Mo
metal
fossa-eminence
prosthesis
(partial
joint
replacement
system;
TMJ
Im-
plant,
Inc,
Golden,
CO)
since
1988
and
recently
re-
ported
on
an
8-year
retrospective
pilot
study
on
the
surgical
management
of
advanced
degenerative
arthri-
tis
of
TMJ
with
metal
fossa-eminence
hemi-joint
re-
placement
prosthesis.
3
We
concluded
"the
surgical
placement
of
the
partial
joint
replacement
provided
significant
focal
preauricular
pain
relief
and
reduced
TMJ
dysfunction
secondary
to
advanced
degenerative
arthritis."
The
purposes
of
the
current
study
are
to
quantify
the
kinematics
of
TMJ
function
in
healthy
individuals
and
to
determine
the
kinematics
of
TMJ
function
in
patients
following
unilateral
TMJ
arthrotomy
with
metal
fossa-eminence
partial
joint
replacement.
Materials
and
Methods
SUBJECTS
Fourteen
healthy
volunteers
(11
women,
3
men;
mean
age,
31.4
years)
participated
in
the
study.
All
participants
were
at
least
18
years
of
age.
All
subjects
had
complete
dentitions
except
third
molars
and
an-
gle
Class
I
occlusion
without
obvious
abnormalities
such
as
a
cross
bite
or
an
excessive
overbite
(>5
mm).
Volunteers
were
checked
for
signs
or
symptoms
for
TMJ
disorders;
history
of
pain
or
noise
in
the
TMJ,
pain
and/or
fatigue
of
the
masticatory
muscles,
im-
paired
jaw
mobility,
facial
pain,
headache,
and
odon-
talgia.
No
signs
or
symptoms
were
present
at
the
time
of
study
testing.
Also,
none
of
the
normal
subjects
had
undergone
major
dental
treatment
within
the
last
3
years
(such
as
orthodontics,
orthognathic
surgery,
or
extensive
restorative
therapy).
Thirteen
female
patients
(mean
age,
45
years;
range,
31
to
61
years)
who
had
undergone
unilateral
surgical
reconstruction
of
advanced
degenerative
TMJ
arthritis
participated
in
this
study.
All
patients
had
unilateral
TMJ
arthrotomy
with
metal
fossa-eminence
partial
joint
replacement
(Christensen
TMJ
implant
system;
TMJ
Implant
Inc,
Golden,
CO).
Surgical
selec-
tion
criteria
at
our
institution
are
previously
pub-
lished.
3
The
minimum
postoperative
follow-up
was
4
years.
To
insure
consistent
surgical
technique
and
treatment
protocol,
patients
of
1
surgeon
were
stud-
ied.
The
aim
and
protocol
of
this
study
was
explained
to
all
participants
before
starting
the
kinematic
re-
cordings.
All
subjects
provided
written
informed
con-
sent
to
participate.
This
study
was
approved
by
the
authors'
Institutional
Review
Board.
DATA
COLLECTION
Subjective
Data
Information
regarding
the
surgical
patient's
previ-
ous
nonsurgical/surgical
TMJ
treatments
and
symp-
toms
was
obtained
from
the
institutional
records
of
YOON
ET
AL
1571
Table
1.
PATIENT
QUESTIONNAIRE:
PRESURGICAL
AND
CURRENT,
VAS
(1-30)
1.
Pain
intensity
(0
=
no
pain,
30
=
severe,
intense,
incapacitating
pain)
2.
Chewing
ability
(0
=
no
problem,
30
=
impossible
to
chew)
3.
Jaw
opening
(0
=
no
opening
problem,
30
=
no
opening)
4.
Joint
noise
(0
=
no
noise,
30
=
severe
annoying
noise)
5.
Satisfaction
with
surgical
result
(0
=
no
satisfaction,
30
=
complete
satisfaction)
6.
Pain
experience
(presurgical
and
current,
1-6)
0
=
no
pain
1
=
some
pain,
which
you
easily
can
disregard
2
=
some
pain,
which
you
cannot
disregard
but
does
not
make
your
usual
activities
more
difficult
3
=
pain
that
makes
concentration
on
more
demanding
task
more
difficult
4
=
pain
that
makes
most
things
you
do
more
difficult
except
the
most
basic
5
=
pain
that
is
so
severe
that
you
have
to
rest
6
=
pain
that
is
so
severe
you
cannot
stand
it
Yoon
et
al.
Normal
Versus
Postsurgical
TMJ
Kinematics.
J
Oral
Maxillofac
Surg
2007.
Mayo
Clinic,
Rochester,
MN,
and
confirmed
by
the
first
author
before
the
experimental
study.
Subjective
presurgical
and
current
data
regarding
pain
intensity,
chewing
ability,
jaw
opening,
joint
noise,
and
overall
satisfaction
with
surgical
treatment
were
collected
using
a
visual
analog
scale
of
30
mm
in
length.
Pain
experience
was
collected
using
a
1
to
6
rating
system
(fable
1).
Patients
were
asked
to
com-
plete
questionnaires
according
to
their
presurgical
and
postsurgical
experiences,
retrospectively.
Objective
Data
Mandibular
incisor
and
condylar
motion
were
col-
lected
using
a
method
developed
by
the
authors
(de-
tails
of
this
method
can
be
found
in
a
previous
arti-
cle).
8
An
electromagnetic
tracking
device
(3Space
Fastrak
System;
Polhemus,
Colchester,
VT)
(static
ac-
curacy
of
0.8
mm
RMS
for
translation,
0.15°
RMS
for
orientation)
and
accompanying
software
(The
Motion-
Monitor;
Innovative
Sports
Training,
Inc,
Chicago,
IL)
were
used
to
record
the
3-dimensional
kinematics
of
the
mandible
relative
to
the
temporal
bone.
This
was
achieved
by
attaching
1
electromagnetic
sensor
to
the
upper
and
1
to
the
lower
plastic
dental
brackets
(Fig
1).
The
magnetic
source
was
placed
posterior
to
the
pa-
tient's
shoulder
just
inferior
to
the
height
of
the
sensors
using
a
Plexiglas
mounting
bracket
(Fig
2).
A
custom,
calibrated
Plexiglas
digitizing
probe
was
used
to
lo-
cate
anatomic
points
for
defining
the
anatomic
coor-
dinate
systems
and
for
defining
landmarks
of
interest.
In
addition,
4
anatomic
landmarks,
the
mid-superior
edge
of
the
lower
central
incisors,
the
mid-inferior
,_
erg
FIGURE
1.
Custom
dental
appliances
and
plastic
brackets
with
electromagnetic
sensors
attached.
Yoon
et
al.
Normal
Versus
Postsurgical
TMJ
Kinematics.
J
Oral
Maxillofac
Surg
2007.
edge
of
the
upper
central
incisors,
and
the
lateral
pole
of
the
right
and
left
TMJ
condyles
were
digitized
to
be
tracked
in
3-dimensional
space
(Fig
3).
The
positions
of
the
anatomic
condylar
points
were
determined
by
palpating
the
deepest
point
of
condylar
fossa
curva-
ture
during
opening
and
closing
movements
of
the
mouth
and
digitizing
reference
points
5
mm
inferior
from
the
palpated
points.
Three
trials
of
protrusive-retrusive
movements,
opening-closing,
and
lateral
(right
and
left)
move-
ments
were
performed
at
a
rhythm
of
approxi-
mately
1
complete
excursive
movement
every
2
seconds.
Subjects
were
instructed
to
perform
each
movement
maximally,
symmetrically,
and
as
smoothly
as
possible.
Each
movement
started
and
ended
in
the
maximum
intercuspal
position.
Before
each
recording,
participants
were
given
the
oppor-
tunity
to
practice
the
required
task.
Position
and
rotation
of
the
mandible
were
obtained
dynamically
FIGURE
2.
Experimental
setup
for
kinematic
data
collection
including
electromagnetic
source
and
sensors.
Yoon
et
al.
Normal
Versus
Postsurgical
TMJ
Kinematics.
J
Oral
Maxillofac
Surg
2007.
1572
NORMAL
VERSUS
POSTSURGICAL
TMJ
IUNEMATICS
*5
6*
A)
B)
FIGURE
3.
A,
Coordinate
system
and
trajectories
(in
gray)
of
condy-
lar
and
incisor
motion
in
the
sagittal
plane
from
a
representative
subject.
B,
Digitized
anatomic
landmarks
used
for
defining
anatomic
coordinate
systems.
Z
axis
direction
corresponds
to
the
vector
defined
by
the
right
and
left
mesio-buccal
cusps
of
the
lower
first
molars
(point
1
to
2).
X
axis
direction
is
defined
as
the
perpendicular
to
the
plane
defined
by
points
1,
2,
and
3
(the
mid-superior
edge
of
the
lower
central
incisors).
The
Y
axis
is
defined
as
the
cross-product
of
the
Z
and
X
vectors.
The
origin
of
the
coordinate
system
is
located
at
point
4
(the
mid-inferior
edge
of
the
upper
central
incisors).
Four
anatomic
land-
marks
were
used
to
monitor
condylar
and
incisor
motion,
the
mid-
superior
edge
of
the
lower
central
incisors
(point
3),
the
mid-inferior
edge
of
the
upper
central
incisors
(point
4),
and
the
lateral
pole
of
the
right
and
left
TMJ
condyles
(points
5
and
6).
Yoon
et
al.
Normal
Versus
Postsurgical
TMJ
Kinematics.
J
Oral
Maxillofac
Surg
2007.
in
the
anatomic
coordinate
system
during
the
move-
ments.
After
jaw
motion
was
recorded,
the
plastic
dental
brackets
were
removed
with
an
orthodontic
debonding
instrument.
Any
residual
adhesive
on
the
teeth
was
removed
with
hand
or
rotary
instru-
mentation.
A
final
prophylaxis
of
the
involved
teeth
was
performed.
Data
Analysis
Pain
and
functional
capability
were
analyzed
by
mean
values
and
t
test
(P
<
.05)
to
compare
the
preoperative
status
with
current
status.
t
tests
were
also
used
to
detect
the
differences
in
TMJ
kinemat-
ics
between
the
healthy
subject
group
and
the
surgical
patient
group.
Only
opening
portions
of
the
best
3
trials
were
selected
from
the
time
series
data
to
represent
the
movement.
Figure
4
depicts
a
representative
sagittal
and
frontal
view
of
the
time
series
data
for
the
condyles
and
incisor.
The
linear
distance
(LD)
in
mm
(ie,
the
LD
be-
tween
the
start
and
end
position)
was
calculated
for
the
lower
incisor
landmark
and
both
condyles
dur-
ing
the
opening
and
protrusive
movements
in
the
sagittal
(X-Y)
plane
and
during
the
lateral
move-
ments
in
the
frontal
(X-Z)
plane.
The
total
deviation
of
the
lower
incisor
(ie,
distance
from
greatest
left
deviation
to
greatest
right
deviation)
and
both
con-
dyles
were
calculated
during
the
opening
and
pro-
trusive
movements
in
the
frontal
(X-Z)
plane.
Results
QUESTIONNAIRES
In
the
surgical
patient
group,
mean
preoperative
symptom
duration
was
70
months
(range,
0
to
360
months).
Mean
follow-up
period
(years
between
surgery
and
data
collection)
was
90
months
(range,
50
to
140
months).
The
average
number
of
previous
open
surgical
treatments
in
the
patients
who
had
previous
TMJ
surgery
was
2
(range,
1
to
6).
Two
patients
had
not
received
prior
open
surgical
treat-
ment.
All
clinical
outcomes
improved
significantly
(P
<
.05)
and
included:
pain
experience
(76%),
pain
intensity
(60.6%),
chewing
ability
(53.0%),
jaw
opening
(40.7%),
and
joint
noise
(53.6%).
Mean
satisfaction
with
the
sur-
gical
result
was
25.7
on
a
scale
of
1
to
30
(fable
2).
KINEMATICS
Mean
LDs
(LD
in
mm)
and
standard
deviations
for
mandibular
incisor
and
condyles
for
both
healthy
subjects
and
surgical
patients
were
calculated
and
summarized
in
Table
3.
During
all
movements,
LD
measurements
for
right
and
left
condyles
of
healthy
patients
were
not
significantly
different;
therefore,
we
combined
the
data
from
right
and
left
to
sim-
plify
the
comparison
analysis
with
surgical
patients.
Mandibular
incisor
measurements
for
normal
sub-
jects
were
not
significantly
different
during
right
and
left
lateral
movements
so
they
were
also
com-
bined
to
simplify
the
comparison
analysis.
Condyle
motion
was
analyzed
in
3
groups:
normal
subjects
condyle
(NC),
operated
condyle
(OC),
and
unoper-
ated
condyle
(UC).
OPENING
MOVEMENTS
Mean
LD
of
incisors
during
maximal
mouth
open-
ing
for
the
surgical
patient
group
was
35.0
±
6.9
mm
and
18%
less
than
the
normal
subjects
(43.6
±
5.6
mm;
P
<
.01;
Fig
5).
Mean
LD
for
mandibular
right
and
left
condyles
was
symmetrical
in
the
nor-
mal
group
(16.5
±
5.7
and
16.5
±
5.1
mm,
respec-
A
I
condylar
LD
1psilateral
Contralateral
condyle
condyle
1
4
Incisor
LD
Direction
of
lateral
motion
FIGURE
4.
A,
Trajectories
of
condylar
and
incisor
motion
in
the
sagittal
plane
from
a
representative
subject.
B,
To
simplify
the
statistical
analyses
and
presentation,
condylar
data
during
lateral
movements
were
defined
as
ipsilateral
and
contralateral
condylar
data.
Yoon
et
al.
Normal
Versus
Postsurgical
TMJ
Kinematics.
J
Oral
Maxillofac
Surg
2007.
YOON
ET
AL
1573
Table
2.
CLINICAL
OUTCOME
DATA
(MEAN
±
SD,
Preoperative
Postoperative
Improvement
Percentage
Pain
experience
(0
to
6)*
4.7
±
1.3
1.6
±
1.4*
76%
Pain
intensity
(0
to
30)*
23.6
±
5.3
9.3
±
7.8*
60.6%
Chewing
difficulty
(0
to
30)*
18.3
±
6.1
8.6
±
7.2*
53%
Jaw
opening
difficulty
(0
to
30)*
18.7
±
8.8
11.1
±
10.2*
40.7%
Joint
noise
(0
to
30)*
18.6
±
10.1
7.9
±
6.4*
53.6%
Satisfaction
with
surgical
result
(0
to
30)
25.7
±
5.1
Abbreviation:
VAS,
visual
analog
scale.
*Statistical
significance
at
P
<
.05
(paired
t
test).
Yoon
et
al.
Normal
Versus
Postsurgical
TMJ
Kinematics.
J
Oral
Maxillofac
Surg
2007.
tively);
however,
in
the
surgical
patient
group,
mea-
surements
for
operated
condyle
and
unoperated
condyle
were
asymmetric
(7.1
±
3.1
mm
and
12.2
±
3.1
mm,
respectively;
P
<
.01)
and
reduced
as
compared
with
normal
subjects
by
57%
and
36%,
respectively
(Fig
6).
In
addition,
the
magnitude
of
mandibular
incisor
deviation
was
significantly
less
(55%)
in
the
surgical
patient
group
as
compared
with
the
normal
group
(2.7
±
2.2
mm
vs
5.8
±
2.7,
respectively;
P
<
.01).
PROTRUSIVE
MOVEMENTS
In
protrusive
movements,
the
mean
LD
measure-
ments
for
incisor
and
condyles
of
normal
subjects
showed
a
symmetric
pattern
(9.0
±
1.9,
9.0
±
2.1,
and
8.7
±
2.1
mm,
respectively).
However,
we
did
not
see
the
same
pattern
in
the
surgical
patient
group
(mean
incisor
ID
was
5.1
±
1.7
mm
[44.4%
less]
compared
with
the
normal
group;
P
<
.01).
In
the
surgical
patient
group,
the
operated
condyle
traveled
51.8%
less
as
com-
pared
with
the
unoperated
condyle
(3.4
±
2.9
vs
6.9
±
2.0
mm,
respectively;
P
<
.01).
Additionally,
the
magni-
tude
of
mandibular
incisor
deviation
was
significantly
more
in
the
surgical
patient
group
as
compared
with
the
normal
group
(3.3
±
1.7
vs
1.9
±
1.3
mm,
respectively;
P
<
.01).
In
summary,
the
protrusive
movements
of
operated
and
unoperated
condyles
of
surgical
patients
moved
significantly
differently
(P
<
.01)
as
compared
Table
3.
KINEMATIC
DATA:
MANDIBULAR
INCISOR
AND
CONDYLAR
MOVEMENTS
FOR
NORMAL
SUBJECT
GROUP
(N
=
14)
AND
SURGICAL
TEMPOROMANDIBULAR
HEMI-JOINT
ARTHROTOMY
PATIENT
GROUP
(N
=
13,
MEAN
±
SD,
mm)
Opening-Closing
Protrusive
Right
Lateral
Left
Lateral
Incisor
of
normal
subjects
Ld
43.6
±
5.6
9.0
±
1.9
11.8
±
2.9
12.1
±
2.9
Dev
2.7
±
2.2
1.9
±
1.3
Right
condyle
of
normal
subjects
Ld
16.5
±
5.7
9.0
±
2.1
2.7
±
1.3
7.9
±
3.0
Dev
2.3
±
1.7
1.3
±
1.1
(ipsilateral)
(contralateral)
Left
condyle
of
normal
subjects
Ld
16.5
±
5.1
8.7
±
2.1
7.1
±
1.9
3.1
±
1.4
Dev
2.2
±
2.0
1.3
±
1.0
(contralateral)
(ipsilateral)
Toward
operated
side
Away
from
operated
side
Incisors
of
Patients
Ld
35.0
±
69*
5.1
±
1.7*
9.4
±
2.5t
5.1
±
3.0*
Dev
5.8
±
2.7*
3.3
±
1.7t
Operated
condyle
of
patients
Ld
7.1
±
3.1*#
3.4
±
2.9*#
3.1
±
1.2
3.4
±
2.1**
Dev
1.6
±
0.8
1.2
±
0.7
(ipsilateral)
(contralateral)
Nonoperated
condyle
of
patients
Ld
12.2
±
3.1t
6.9
±
2.0*
6.4
±
2.4
2.1
±
1.3
Dev
2.1
±
1.1
1.2
±
0.8
(contralateral)
(ipsilateral)
Abbreviations:
LD,
linear
distance;
Dev,
deviation.
*Statistical
significance
between
normal
vs
surgical
patient
group
at
P
<
.01
(paired
t
test).
tStatistical
significance
between
normal
vs
surgical
patient
group
at
P
<
.05
(paired
t
test).
*Statistical
significance
between
unoperated
condyle
vs
operated
condyle
in
surgical
patient
group
at
P
<
.01
(paired
t
test).
Yoon
et
al.
Normal
Versus
Postsurgical
TMJ
Kinematics.
J
Oral
Maxillofac
Surg
2007.
50
-
E
E
30
-
I
20
-
m
10-
I
I
0
40
-
12
8
10
E
E
4
2
2
1574
NORMAL
VERSUS
POSTSURGICAL
TMJ
IUNEMATICS
Incisor
Kinematics
Normals
operated
opening
protrusive
towards
away
from
operated
ope
ated
Lateral
Movement:
Condyle
Kinematics
Normal
Condyle
Operated
condyle
Un-operated
condyle
lasilateral
side
Contralateral
side
FIGURE
7.
Condylar
kinematics
for
lateral
movements;
mean
LD
recorded
for
ipsilateral
and
contralateral
condyle.
Yoon
et
al.
Normal
Versus
Postsurgical
TMJ
Kinematics.
J
Oral
Maxillofac
Surg
2007.
FIGURE
5.
Incisor
kinematics
during
opening,
protrusive,
and
lateral
movements.
Yoon
et
al.
Normal
Versus
Postsurgical
TMJ
Kinematics.
J
Oral
Maxillofac
Surg
2007.
with
condyles
of
normal
subjects,
which
moved
almost
identically
(Fig
6).
LATERAL
MOVEMENTS
During
the
lateral
movement,
condyles
follow
dif-
ferent
patterns
from
each
other.
To
overcome
this
confusion,
condyles
during
lateral
motion
were
de-
fined
as
ipsilateral
and
contralateral
(Fig
4B).
Mean
LD
measured
for
incisor
and
condyles
during
right
and
left
lateral
movements
were
not
statistically
different;
therefore,
they
were
combined
to
simplify
the
com-
parison
analysis.
The
combined
mean
LD
measured
during
lateral
movements
for
incisors,
contralateral
condyle,
and
ipsilateral
condyle
of
the
normal
group
was
12.0
±
3.0,
7.5
±
2.5,
and
2.9
±
1.4
mm,
respectively.
For
the
surgical
patient
group,
the
mean
incisor
LD
away
from
the
operated
side
(5.1
±
3.0
mm;
P
<
.01)
and
toward
the
operated
side
(9.4
±
2.5
mm;
P
<
.05)
as
compared
with
the
normal
group
incisors
(12.0
±
3.0
mm)
were
reduced
by
67%
and
32%,
respectively.
Opening
&
Protrusive
Movement:
Condyle
Kinematics
25
-
20
r
E
15
10
Normal
condyle
DOperated
condyle
Un-operated
condyle
I
I
Opening
Protrusive
FIGURE
6.
Condyle
kinematics
during
opening-closing
and
protru-
sive
movements.
Yoon
et
al.
Normal
Versus
Postsurgical
TMJ
Kinematics.
J
Oral
Maxillofac
Surg
2007.
In
the
operated
patients,
LD
measurements
of
the
contralateral
side
on
the
operated
condyle
(3.4
±
2.1
mm)
showed
significantly
less
motion
(P
<
.01)
than
the
other
2;
55%
less
than
normal
condyle
(7.5
±
2.5
mm)
and
47%
less
than
unoperated
condyle
(6.4
±
2.4
mm).
However,
on
the
ipsilateral
side,
the
unop-
erated
condyle
motion
(2.1
±
1.3
mm)
was
less
than
the
others;
38%
less
than
normal
condyle
(2.9
±
1.4
mm)
and
42%
less
than
operated
condyle
(3.1
±
1.2
mm)
(Fig
7).
Discussion
After
placement
of
a
mandibular
condylar,
or
total
or
hemi-
temporomandibular
joint
prosthesis,
loss
of
translational
movements
of
the
mandible
on
the
op-
erated
side
is
often
observed,
especially
in
an
anterior
direction.
Some
investigators
attribute
this
effect
to
loss
of
lateral
pterygoid
muscle
function
secondary
to
the
condylectomy
on
the
operated
side.
However,
several
other
factors
can
be
responsible
for
loss
of
mandibular
translational
movements
following
TMJ
surgery.
These
include
generalized
scarring
of
the
joint
region
itself
and
scarring
of
the
associated
mus-
cles
of
mastication.
These
chronically
impaired
man-
dibular
movements
frequently
remain
long
term,
despite
complete
healing
and
replacement
of
the
con-
dylar
and/or
fossa
eminence
anatomy.
It
is
reasonable
to
expect
that
patients
who
have
undergone
multiple
TMJ
surgeries
will
always
have
significant
restricted
jaw
motion.
9
Robinson
10
described
a
"false"
stainless
steel
TMJ
fossa
prosthesis
that
was
placed
as
a
type
of
box
against
the
temporal
bone
fossa
and
eminence.
Al-
though
the
patient
had
no
functioning
external
ptery-
goid
muscle,
some
anterior
movement
of
the
mandi-
ble
was
noticed.
This
motion
was
attributed
to
the
forward
angled
force
vector
of
the
remaining
masti-
catory
muscles
and
the
absence
of
the
posterior
slope
of
the
articular
eminence,
which
would
theoretically
block
any
forward
movement.
Kiehn
et
a1
11
used
PMMA
cement
to
fit
and
fix
a
total
joint
prosthesis;
and
a
lack
of
lateral
motion
of
YOON
ET
AL
1575
the
jaw
was
observed,
"possibly
due
to
the
absence
of
the
function
of
the
lateral
pterygoid
muscle,
which
cannot
be
preserved."
Sonnenburg
and
Sonnenburg
12
reported
that
lateral
jaw
movements
were
limited
to
1
mm
(right
or
left)
following
prosthetic
condyle
replacement.
In
addition,
protrusive
movements
were
no
longer
possible,
which
was
attributed
to
loss
of
attachment
of
the
lateral
pterygoid
muscle.
It
was
concluded
that
a
prosthesis
cannot
take
over
function
of
a
healthy
joint
and
therefore
does
not
have
to
be
an
anatomic
copy.
Wolford
et
al
5
'
13
noted
that
lateral
and
protrusive
function
of
the
mandible
were
2
mm
or
less
(right
or
left)
following
total
TMJ
replacement
prosthesis;
and
reattaching
the
lateral
pterygoid
mus-
cle
to
the
prosthetic
condyle
did
not
improve
the
movements
significantly.
van
Loon
et
a1
9
concluded
the
loss
of
lateral
jaw
movement
as
a
great
disadvan-
tage
to
total
TMJ
prosthesis
replacement;
therefore,
a
future
prosthesis
must
allow
the
anterior
movement
of
the
mandible
on
the
operated
side
when
the
mouth
is
opened
and
also
allow
some
mediolateral
(lateral)
translation.
They
recommended
optimizing
the
shape
of
the
articulating
surfaces
based
on
wear
tests,
and
confirmation
of
good
clinical
performance
on
long-
term
follow-up
studies.
Mercuri
et
a1
14
showed
a
24%
improvement
in
mouth
opening
2
years
post
total
TMJ
replacement;
at
the
10
year
follow-up
a
30%
increase
was
noted.
On
the
other
hand,
at
2
years
postimplantation
there
was
a
14%
decrease
in
left
lateral
excursion
and
a
25%
decrease
in
right
lateral
excursion
from
the
preim-
plantation
data.
At
9
years,
the
decrease
in
left
lateral
excursion
and
right
lateral
excursion
was
31%
and
30%,
respectfully.
They
described
that
the
unilaterally
reconstructed
patient
will
exhibit
greater
lateral
ex-
cursion
to
the
reconstructed
side
than
to
the
nonre-
constructed
side.
This
is
attributable
not
only
to
the
loss
of
lateral
pterygoid
function
on
the
implanted
side
but
also
to
the
formation
of
periarticular
scar
tissue
on
the
operated
side.
Bilaterally
reconstructed
rheumatoid
arthritis
patients
and
patients
who
under-
went
2
or
fewer
prior
TMJ
operations
(in
contrast
to
multioperated
patients),
often
display
greater
post-
implantation
lateral
excursion.
This
may
be
attributed
to
recruitment
of
suprahyoid,
masseter,
and
medial
pterygoid
muscle
function
as
well
as
the
lack
of
peri-
articular
scarring
in
the
minimally
operated
patients.
Recently,
Collins
et
a1
15
reported
that
reattachment
of
the
lateral
pterygoid
muscle
to
the
condylar
stump
during
total
joint
reconstructive
surgery
may
provide
the
patient
with
greater
interincisal
opening,
lateral
excursions,
and
protrusive
movement.
However,
this
observation
was
not
quantitated.
Although
favorable
results
have
been
reported
fol-
lowing
TMJ
reconstruction
using
the
partial
or
total
TMJ
replacement
systems
,3,14,16-18
most
data
to
eval-
uate
the
results
have
been
collected
by
subjective
surveys
or
mandibular
incisor
motion
rather
than
con-
dylar
motion.
Our
kinematic
method
tracks
both
the
condyle
and
incisors
path
of
motion.
This
method
allows
the
clinician
and
research
scientist
a
better
analysis
of
the
functional
surgical
outcome.
In
the
present
study,
the
authors
obtained
postop-
erative
subjective
data
from
a
patient
group
that
re-
ceived
reconstruction
with
the
metal
hemi-joint
fossa-
eminence
TMJ
prostheses.
The
patient
questionnaires
in
this
study
documented
significant
improvement
in
all
clinical
outcome
measures
including
pain
experi-
ence,
pain
intensity,
chewing
ability,
jaw
opening,
and
joint
noise.
Importantly,
mean
satisfaction
with
the
surgical
result
was
25.7
on
a
scale
of
1
to
30.
In
addition,
kinematic
measurements
of
the
TMJ
of
healthy
volunteers
and
surgical
TMJ
patients
(unilat-
eral
hemi-joint
replacement)
were
obtained
using
the
electromagnetic
tracking
device
and
custom
dental
appliance.
We did
not
match
age
and
genders
in
our
control
group
with
those
of
the
patients
group,
which
is
a
limitation
of
our
study.
This
should
be
done
for
future
studies.
In
our
operated
group,
the
condyle
and
associated
lateral
pterygoid
muscle
attachments
were
preserved
intraoperatively
by
minimal
condylar
recontouring
or
performing
a
selective
(1
to
3
mm)
condylotomy.
The
amount
of
mandibular
incisal
and
condylar
movement
was
good
after
surgery.
We
hypothesize
that
this
outcome
is
partly
related
to
the
more
con-
servative
surgical
management
(hemi-
vs
total
joint
reconstruction)
where
the
condyle
and
lateral
ptery-
goid
muscle
are
preserved.
However,
there
was
a
significant
difference
in
the
amount
of
mandibular
incisal
and
condylar
motion
during
opening,
protru-
sive,
and
lateral
movements
between
postoperative
patients
and
healthy
subjects.
This
showed
less
than
ideal
postsurgical
condylar
motion
(anterior
and
lat-
eral)
because
of
postsurgical
(current
and
previous)
muscular
or
peri-articular
scarring
morbidity.
Post
TMJ
arthrotomy
patients
showed
significant
antero-posterior
and
lateral
condylar
motion,
indicat-
ing
preservation
of
functional
masticatory
function
(including
lateral
pterygoid
muscle)
following
TMJ
hemi-joint
replacement
with
fossa-eminence
metal
prosthesis;
however,
when
compared
with
normal
subjects,
this
motion
was
still
less
than
normal.
A
prospective
study
for
the
comparison
between
preoperative
and
postoperative
condylar
motion
re-
sults
on
the
same
patient
population
is
necessary
and
ongoing
at
our
medical
center.
We
theorize
preservation
of
the
condyle
in
osteo-
arthritic
patients
undergoing
reconstructive
TMJ
sur-
gery
is
an
important
functional
goal.
In
this
study,
patients
showed
significant
improve-
ment
in
functional
(jaw motion,
joint
noise)
and
qual-
1576
NORMAL
VERSUS
POSTSURGICAL
TMJ
KINEMATICS
ity
of
life
(pain
reduction,
overall
satisfaction)
issues
following
hemi-joint
reconstruction
with
a
hemi-joint
fossa-eminence
metal
prosthesis.
References
1.
Saeed
NR,
McLeod
NM,
Hensher
R:
Temporomandibular
joint
replacement
in
rheumatoid-induced
disease.
Br
J
Oral
Maxillo-
fac
Surg
39:71,
2001
2.
Widmark
G:
On
surgical
intervention
in
the
temporomandibu-
lar
joint.
Swed
Dent
J
Suppl
123:1,
1997
3.
Park
J,
Keller
EE,
Reid
KI:
Surgical
management
of
advanced
degenerative
arthritis
of
temporomandibular
joint
with
metal
fossa-eminence
hemijoint
replacement
prosthesis:
An
8-year
retrospective
pilot
study.
J
Oral
Maxillofac
Surg
62:320,
2004
4.
Mercuri
LG:
Alloplastic
temporomandibular
joint
reconstruc-
tion.
Oral
Surg
Oral
Med
Oral
Pathol
Oral
Radiol
Endod
85:631,
1998
5.
Wolford
LM,
Pitta
MC,
Reiche-Fischel
0,
et
al:
TMJ
concepts/
Techmedica
custom-made
TMJ
total
joint
prosthesis:
5-year
follow-up
study.
Int
J
Oral
Maxillofac
Surg
32:268,
2003
6.
Mercuri
LG:
The
TMJ
concepts
patient
fitted
total
temporoman-
dibular
joint
reconstruction
prosthesis.
Oral
Maxillofac
Surg
Clin
North
Am
12:73,
2000
7.
Mercuri
LG:
The
use
of
alloplastic
prostheses
for
temporoman-
dibular
joint
reconstruction.
J
Oral
Maxillofac
Surg
58:70,
2000
8.
Yoon
HJ,
Zhao
ICD,
Rebellato
J,
et
al:
Kinematic
study
of
the
mandible
using
an
electromagnetic
tracking
device
and
custom
dental
appliance:
Introducing
a
new
technique.
J
Biomech
39:2325,
2006
9.
van
Loon
JP,
de
Bont
GM,
Boering
G:
Evaluation
of
temporo-
mandibular
joint
prostheses:
Review
of
the
literature
from
1946
to
1994
and
implications
for
future
prosthesis
designs.
J
Oral
Maxillofac
Surg
53:984,
1995
10.
Robinson
M:
Temporomandibular
ankylosis
corrected
by
cre-
ating
a
false
stainless
steel
fossa.
J
S
Calif
S
Dent
Assoc
28:186,
1960
11.
Kiehn
CL,
DesPrez
JD,
Converse
CF:
Total
prosthetic
replace-
ment
of
the
temporomandibular
joint.
Ann
Plast
Surg
2:5,
1979
12.
Sonnenburg
I,
Sonnenburg
M:
Total
condylar
prosthesis
for
alloplastic
jaw
articulation
replacement.
J
Maxillofac
Surg
13:
131,
1985
13.
Wolford
LM,
Cottrell
DA,
Henry
CH:
Temporomandibular
joint
reconstruction
of
the
complex
patient
with
the
Techmedica
custom-made
total
joint
prosthesis.
J
Oral
Maxillofac
Surg
52:2,
1994
14.
Mercuri
LG,
Wolford
LM,
Sanders
B,
et
al:
Long-term
follow-up
of
the
CAD/CAM
patient
fitted
total
temporomandibular
joint
reconstruction
system.
J
Oral
Maxillofac
Surg
60:1440,
2002
15.
Collins
CP,
Wilson
KJ,
Collins
PC:
Lateral
pterygoid
myotomy
with
reattachment
to
the
condylar
neck:
An
adjunct
to
restore
function
after
total
joint
reconstruction.
Oral
Surg
Oral
Med
Oral
Pathol
Oral
Radiol
Endod
95:672,
2003
16.
Chase
DC,
Hudson
JW,
Gerard
DA,
et
al:
The
Christensen
prosthesis.
A
retrospective
clinical
study.
Oral
Surg
Oral
Med
Oral
Pathol
Oral
Radiol
Endod
80:273,
1995
17.
McLeod
NM,
Saeed
NR,
Hensher
R:
Internal
derangement
of
the
temporomandibular
joint
treated
by
discectomy
and
hemi-
arthroplasty
with
a
Christensen
fossa-eminence
prosthesis.
Br
J
Oral
Maxillofac
Surg
39:63,
2001
18.
Wolford
LM,
Dingwerth
DJ,
Talwar
RM,
et
al:
Comparison
of
2
temporomandibular
joint
total
joint
prosthesis
systems.
J
Oral
Maxillofac
Surg
61:685,
2003