What are the clinical implications of knee crepitus to individuals with knee osteoarthritis? An observational study with data from the Osteoarthritis Initiative

Abstract

Background:
Crepitus is a common clinical feature of knee osteoarthritis. However, the importance of crepitus in the overall clinical presentation of individuals with knee osteoarthritis is unknown.

Objective(s):
(A) To compare function, pain and quality of life between individuals with knee osteoarthritis with and without crepitus; (B) to compare whether individuals with knee osteoarthritis in both knees, but crepitus in just one, differ in terms of function pain, and knee strength.

Methods:
Setting: Observational study.

Participants:
(A) A total of 584 participants with crepitus who had the same Kellgren-Lawrence grade on both knees were matched for gender, body mass index and Kellgren-Lawrence grade to participants without crepitus on both knees. (B) 361 participants with crepitus in only one knee and with the same Kellgren-Lawrence grade classification on both knees were included.

Main outcome measure(s):
A - Self-reported function, pain, quality of life, 20-m walk test and chair-stand test. B -Knee extensor and flexor strength, self-reported function and pain.

Results:
A - Individuals with crepitus had lower self-reported function, quality of life and higher pain compared to those without crepitus (3-11%; small effect=0.17-0.41, respectively). No difference was found in objective function between groups. B - Self-reported function was lower in the limb with crepitus compared to the limb without crepitus (15%; trivial effect=0.09). No difference was found in pain and knee strength between-groups.

Conclusion(s):
Individuals with knee osteoarthritis and knee crepitus have slightly lower self-reported physical function and knee-related quality of life (small or trivial effect). However, the presence of knee crepitus is not associated with objective function or knee strength.

Full text

Please
cite
this
article
in
press
as:
Pazzinatto
MF,
et
al.
What
are
the
clinical
implications
of
knee
crepitus
to
individuals
with
knee
osteoarthritis?
An
observational
study
with
data
from
the
Osteoarthritis
Initiative.
Braz
J
Phys
Ther.
2018,
https://doi.org/10.1016/j.bjpt.2018.11.001
ARTICLE IN PRESS
+Model
BJPT-177;
No.
of
Pages
6
Brazilian
Journal
of
Physical
Therapy
2018;xxx(xx):xxx---xxx
https://www.journals.elsevier.com/brazilian-journal-of-physical-therapy
Brazilian
Journal
of
Physical
Therapy
ORIGINAL
RESEARCH
What
are
the
clinical
implications
of
knee
crepitus
to
individuals
with
knee
osteoarthritis?
An
observational
study
with
data
from
the
Osteoarthritis
Initiative
Marcella
Ferraz
Pazzinattoa,b,
Danilo
de
Oliveira
Silvaa,b,
Nathálie
Clara
Fariaa,
Milena
Simicc,
Paulo
Henrique
Ferreira c,
Fábio
Mícolis
de
Azevedoa,∗,
Evangelos
Pappasc
aPhysical
Therapy
Department,
School
of
Science
and
Technology,
Universidade
Estadual
Paulista
‘‘Julio
de
Mesquita
Filho’’
(UNESP),
Presidente
Prudente,
SP,
Brazil
bLa
Trobe
Sports
and
Exercise
Medicine
Research
Centre
(LASEM),
School
of
Allied
Health,
La
Trobe
University,
Bundoora,
Victoria,
Australia
cThe
University
of
Sydney,
Discipline
of
Physiotherapy,
Faculty
of
Health
Sciences,
Sydney,
NSW,
Australia
Received
29
March
2018;
accepted
6
November
2018
KEYWORDS
Knee
osteoarthritis;
Quality
of
life;
Recovery
of
function;
Knee
Abstract
Background:
Crepitus
is
a
common
clinical
feature
of
knee
osteoarthritis.
However,
the
impor-
tance
of
crepitus
in
the
overall
clinical
presentation
of
individuals
with
knee
osteoarthritis
is
unknown.
Objective(s):
(A)
To
compare
function,
pain
and
quality
of
life
between
individuals
with
knee
osteoarthritis
with
and
without
crepitus;
(B)
to
compare
whether
individuals
with
knee
osteoarthritis
in
both
knees,
but
crepitus
in
just
one,
differ
in
terms
of
function
pain,
and
knee
strength.
Methods::
Setting:
Observational
study.
Participants:
(A)
A
total
of
584
participants
with
crepi-
tus
who
had
the
same
Kellgren---Lawrence
grade
on
both
knees
were
matched
for
gender,
body
mass
index
and
Kellgren-Lawrence
grade
to
participants
without
crepitus
on
both
knees.
(B)
361
participants
with
crepitus
in
only
one
knee
and
with
the
same
Kellgren-Lawrence
grade
clas-
sification
on
both
knees
were
included.
Main
outcome
measure(s):
A
---
Self-reported
function,
pain,
quality
of
life,
20-m
walk
test
and
chair-stand
test.
B
--- K n e e
extensor
and
flexor
strength,
self-reported
function
and
pain.
∗Corresponding
author
at:
Rua
Roberto
Simonsen,
305,
CEP:
19060-900,
Presidente
Prudente,
SP,
Brazil.
E-mail:
micolis@fct.unesp.br
(F.M.
Azevedo).
https://doi.org/10.1016/j.bjpt.2018.11.001
1413-3555/©
2018
Associac¸˜
ao
Brasileira
de
Pesquisa
e
P´
os-Graduac¸˜
ao
em
Fisioterapia.
Published
by
Elsevier
Editora
Ltda.
All
rights
reserved.

Please
cite
this
article
in
press
as:
Pazzinatto
MF,
et
al.
What
are
the
clinical
implications
of
knee
crepitus
to
individuals
with
knee
osteoarthritis?
An
observational
study
with
data
from
the
Osteoarthritis
Initiative.
Braz
J
Phys
Ther.
2018,
https://doi.org/10.1016/j.bjpt.2018.11.001
ARTICLE IN PRESS
+Model
BJPT-177;
No.
of
Pages
6
2
M.F.
Pazzinatto
et
al.
Results:
A
--- Individuals
with
crepitus
had
lower
self-reported
function,
quality
of
life
and
higher
pain
compared
to
those
without
crepitus
(3---11%;
small
effect
=
0.17---0.41,
respectively).
No
difference
was
found
in
objective
function
between
groups.
B
---
Self-reported
function
was
lower
in
the
limb
with
crepitus
compared
to
the
limb
without
crepitus
(15%;
trivial
effect
=
0.09).
No
difference
was
found
in
pain
and
knee
strength
between-groups.
Conclusion(s):
Individuals
with
knee
osteoarthritis
and
knee
crepitus
have
slightly
lower
self-
reported
physical
function
and
knee-related
quality
of
life
(small
or
trivial
effect).
However,
the
presence
of
knee
crepitus
is
not
associated
with
objective
function
or
knee
strength.
©
2018
Associac¸˜
ao
Brasileira
de
Pesquisa
e
P´
os-Graduac¸˜
ao
em
Fisioterapia.
Published
by
Elsevier
Editora
Ltda.
All
rights
reserved.
Introduction
Osteoarthritis
(OA)
is
one
of
the
leading
causes
of
pain
and
disability
worldwide
only
surpassed
by
back
pain.4The
prevalence
of
knee
OA
increases
with
age
and
affects
33.6%
of
women
and
24.3%
of
men
who
are
60
years
or
older.20
Individuals
with
late-stage
knee
OA
have
decreased
physi-
cal
function,10,26 quality
of
life2and
are
commonly
elect
to
undergo
total
knee
arthroplasty.11,27
Imaging
has
been
widely
used
to
diagnose
and
grade
knee
OA.6,9,12 However,
the
lack
of
association
between
imaging
and
knee
OA
severity
have
been
responsible
for
a
movement
toward
its
diagnosis
based
on
clinical
findings.5,8 According
to
the
European
League
Against
Rheumatism
(EULAR),
the
association
of
risk
factors
for
knee
OA
(e.g.,
age,
gender,
body
mass
index
(BMI),
occupation);
their
symptoms
(persis-
tent
knee
pain,
morning
stiffness
and
functional
limitation)
and
physical
examination
(crepitus,
restricted
movement
and
bony
enlargement)
can
guide
a
confident
diagnosis
of
knee
OA.28
In
individuals
with
Kellgren---Lawrence
(KL)
grade
of
1---3,
the
presence
of
crepitus
results
in
80%
possibility
of
being
diagnosed
with
knee
OA.28 Lo
et
al.14 reported
that
knee
crepitus
is
a
simple
and
effective
assessment
that
is
predic-
tive
of
longitudinal
development
of
symptomatic
knee
OA.
Another
study,3reported
a
significant
association
between
radiographic
OA
and
the
presence
of
knee
crepitus.
Knee
crepitus
was
also
an
indicator
of
osteoarthritic
lesions
in
the
patellofemoral
joint
identified
with
magnetic
resonance
imaging
in
women
with
knee
OA.23
Despite
being
associated
with
the
development
of
knee
OA
and
structural
damage,
it
is
unknown
whether
knee
crepitus
is
indicative
of
an
overall
poor
clinical
presen-
tation,
including
lower
function,
strength,
quality
of
life
and
higher
pain.1As
individuals
with
knee
pain
often
report
negative
beliefs
regarding
crepitus,22 it
is
important
to
investigate
the
importance
of
crepitus
to
the
over-
all
clinical
presentation
of
individuals
with
knee
OA.
If
crepitus
is
associated
with
poor
function,
this
informa-
tion
would
aid
clinicians
to
potentially
identify
a
clinical
finding
indicative
of
OA
severity.
On
the
other
hand,
if
crepitus
is
not
associated
with
poor
function,
such
infor-
mation
could
be
used
to
manage
patient’s
negative
beliefs
regarding
crepitus
as
a
component
of
an
education
interven-
tion.
The
aims
of
the
study
are
to
(1)
compare
objective
and
self-reported
physical
function,
pain
and
knee-related
qual-
ity
of
life
between
individuals
with
knee
OA
with
and
without
knee
crepitus;
(2)
to
compare
whether
individuals
with
knee
OA
in
both
knees,
but
crepitus
in
just
one,
differ
in
terms
of
knee
extensor
and
flexor
strength,
knee-related
pain
and
self-reported
function.
Methods
This
study
was
performed
using
data
from
the
OA
Initiative
(OAI),
which
is
a
multi-center,
longitudinal
observational
study
of
incident
and
progressive
knee
OA
in
older
adults
(http://www.oai.ucsf.edu).
The
study
rationale
and
general
inclusion
criteria
for
the
OAI
(e.g.,
male
or
female
sex,
age
45---78,
presence
of
symptoms
and/or
knee
radiographic
OA,
or
risk
factors
for
knee
OA)
have
been
published21 and
are
publicly
available
(http://oai.epi-ucsf.org/datarelease).
Participants
were
enrolled
at
five
centers
(Baltimore,
MD;
Columbus,
OH;
Pittsburgh,
PA;
Pawtucket,
RI
and
San
Fran-
cisco,
CA)
between
2004
and
2006
if
they
had
symptomatic
knee
OA.
All
participants
provided
written
informed
con-
sent
and
this
study
received
ethical
approval
from
each
OAI
clinical
site
(Memorial
Hospital
of
Rhode
Island
Institutional
Review
Board,
The
Ohio
State
University’s
Biomedical
Sci-
ences
Institutional
Review
Board,
University
of
Pittsburgh
Institutional
Review
Board,
and
University
of
Maryland
Balti-
more
---
Institutional
Review
Board),
and
the
OAI
coordinating
center
(Committee
on
Human
Research
at
University
of
Cal-
ifornia,
San
Francisco,
California,
United
States
of
America.
Number
10-00532).
Participants
presenting
with
knee
symptoms
(pain,
aching
or
stiffness),
associated
with,
at
least,
one
of
other
risk
fac-
tors
of
OA
such
as
age
>45
years,
overweight,
knee
injury
or
surgery
and
family
history
were
considered
as
having
high
risk
of
developing
knee
OA.
All
assessments
were
conducted
using
a
standardized
protocol
at
each
of
the
centers
that
could
be
found
at
http://www.oai.ucsf.edu.
Participants
underwent
an
examination
by
trained
clinicians.
In
order
to
address
our
aims,
this
study
was
divided
into
parts
A
and
B.

Please
cite
this
article
in
press
as:
Pazzinatto
MF,
et
al.
What
are
the
clinical
implications
of
knee
crepitus
to
individuals
with
knee
osteoarthritis?
An
observational
study
with
data
from
the
Osteoarthritis
Initiative.
Braz
J
Phys
Ther.
2018,
https://doi.org/10.1016/j.bjpt.2018.11.001
ARTICLE IN PRESS
+Model
BJPT-177;
No.
of
Pages
6
Clinical
implications
of
crepitus
in
knee
osteoarthritis
3
Part
A:
A
case-control
design
was
used
to
compare
objective
and
self-reported
physical
function,
pain,
and
knee-related
quality
of
life
between
individuals
with
knee
OA
with
and
without
knee
crepitus.
Part
B:
A
within-subject
design
was
used
to
compare
knee
extensor
and
flexor
strength,
knee-related
pain,
and
self-
reported
physical
function
in
individuals
with
knee
OA
in
both
knees,
but
crepitus
in
only
one.
Crepitus
According
to
the
OAI
guidelines,
clinicians
assessed
for
crepi-
tus
by
placing
the
palm
of
their
hand
over
the
patella
to
evaluate
the
presence
of
a
continuous
grinding
sensa-
tion
during
passive
knee
flexion-extension
movement
in
the
supine
position.
To
ensure
quality
of
data
collection,
all
clinic
staff
underwent
a
rigorous
training.
Part
A
---
case-control
design
Participants
with
knee
OA
and
crepitus
who
had
the
same
KL
grade
on
both
knees
were
matched
for
gender,
BMI
and
KL
grade
to
participants
without
knee
crepitus
on
both
knees.
The
clinical
presentation
of
the
participants
was
assessed
using
performance-based
function
measures
and
self-reported
measures.
Performance-based
function
measures:
The
20-m
walk
test
was
used
to
measure
walking
speed.
Participants
were
asked
to
walk
at
their
usual
walking
pace,
the
timing
began
with
the
first
footfall
over
the
starting
line
and
stopped
with
the
first
footfall
over
the
finish
line
across
20
m.
They
per-
formed
two
trials
and
the
average
speed
was
calculated.
We
have
also
used
the
performance
on
the
repeated
chair-
stand
test
to
assess
function.
Participants
were
asked
to
fold
the
arms
across
the
chest
and
keep
this
position
during
the
whole
test.
Then
the
examiner
provided
the
following
stan-
dardized
instruction
for
all
participants
‘‘I
want
you
to
stand
up
five
times
as
quickly
as
you
can,
keeping
your
arms
folded
across
your
chest.
When
you
stand
up,
come
to
a
full
stand-
ing
position
each
time,
and
when
you
sit
down,
sit
all
the
way
down
each
time’’.
The
time
to
complete
five
chair
rises
was
recorded
in
seconds.
The
test
was
performed
twice
and
the
mean
value
was
used
in
the
analysis.
Self-reported
measures:
To
investigate
self-reported
function,
pain
and
quality
of
life,
patients
were
asked
to
complete
the
following
three
subscales
of
the
Knee
Out-
come
in
Osteoarthritis
Survey
(KOOS):
KOOS-pain,
sport
and
recreational
function
(SRF)
and
knee
related
quality
of
life
(QOL).
Part
B
---
within-subject
design
Participants
with
crepitus
in
only
one
knee
and
with
the
same
KL
grade
classification
on
both
knees
were
included
in
this
analysis.
Performance-based
function
measures:
The
isometric
strength
was
measured
using
the
‘‘Good
Strength
Chair’’
(Metitur
Oy,
Jyvaskyla,
Finland).
The
participants
were
posi-
tioned
sitting,
with
the
back
erect,
their
hip
joints
flexed
at
a
90◦,
and
the
legs
hanging
over
the
edge
of
the
chair
with
their
assessed
knee
joints
flexed
at
60◦.
A
seatbelt
was
used
to
stabilize
the
pelvis,
the
thigh
and
upper
leg
of
the
participant.
The
participants
were
instructed
to
push
(knee
extension
test)
or
pull
(knee
flexion
test)
as
hard
and
as
fast
as
they
can
against
a
pad
(http://www.oai.ucsf.edu).
There
were
two
warm
up
trials
with
50%
effort
and
the
par-
ticipants
performed
three
trials
of
knee
flexion
and
three
trials
of
knee
extension.
The
maximal
force
produced
during
isometric
contraction
was
recorded.
All
participants
were
encouraged
for
about
3
s
and
they
rested
for
30
s
between
trials.
Self-reported
measures:
To
assess
self-reported
physical
function
and
pain,
the
participants
were
asked
to
complete
the
Western
Ontario
and
McMaster
Universities
(WOMAC)
physical
function
and
pain
subscales
for
each
knee.
Statistical
analysis
All
analyses
were
performed
using
the
Statistical
Package
for
the
Social
Sciences
software
program
(IBM
version
23,
SPSS
Inc.,
Chicago,
IL)
with
an
a
priori
level
of
significance
of
0.05.
All
variables
were
assessed
for
normality
and
found
to
be
normally
distributed
based
on
obtainment
of
p
>
0.05
in
the
Kolmogorov---Smirnov
test.
Case-control
design:
Between-groups
differences
in
demographic
measures,
performance-based
functional
tests
and
self-reported
measures
(self-reported
function,
pain
and
quality
of
life)
were
assessed
using
paired
t-tests.
Within-subject
design:
Between-groups
differences
in
maximum
isometric
strength
(knee
flexion
and
knee
exten-
sion),
self-reported
function
and
pain
were
assessed
using
paired
t-tests.
In
order
to
provide
a
more
complete
assessment
of
the
findings
in
addition
to
p-values
we
also
calculated
the
effect
size
(ES;
Hedges’g)
of
each
comparison
using
the
Review
Manager
software
(Version
5.3,
Copenhagen,
Denmark).
The
interpretation
of
the
effect
sizes
values
was
guided
accord-
ing
to
Sullivan
and
Feinn,25 where
<0.2
(trivial
effect),
>0.2
(small),
>0.5
(medium),
>0.8
(large),
and
>1.3
(very
large).
Results
Part
A
A
total
of
584
participants
(292
in
each
group)
were
included
to
the
case-control
design
of
our
study
(Table
1).
Basic
characteristics
indicated
that
the
matching
produced
groups
with
similar
characteristics.
Findings
demonstrated
that
individuals
with
knee
crepitus
had
lower
self-reported
func-
tion
(11%;
small
effect
=
0.36),
knee-related
quality
of
life
(11%;
small
effect
=
0.41)
and
higher
self-reported
pain
(3%;
trivial
=
0.17)
compared
to
those
without
knee
crepi-
tus
(Table
1).
There
was
no
difference
in
performance-based
function
tests
(20
m
walk
test
and
chair-stand
test)
between
groups
(Table
1).
Part
B
For
the
within-subject
analysis,
a
total
of
361
participants
were
included.
Of
those,
178
participants
(49%)
had
crepitus

Please
cite
this
article
in
press
as:
Pazzinatto
MF,
et
al.
What
are
the
clinical
implications
of
knee
crepitus
to
individuals
with
knee
osteoarthritis?
An
observational
study
with
data
from
the
Osteoarthritis
Initiative.
Braz
J
Phys
Ther.
2018,
https://doi.org/10.1016/j.bjpt.2018.11.001
ARTICLE IN PRESS
+Model
BJPT-177;
No.
of
Pages
6
4
M.F.
Pazzinatto
et
al.
Table
1
Characteristics
of
individuals
with
knee
osteoarthritis
presenting
no
crepitus
and
crepitus
(case-control
design).
Variable
No
crepitus
(n
=
292)
Crepitus
(n
=
292)
Mean
difference
(95%
confidence
interval)
Demographics
Age
61.00
(9.58)
61.14
(9.20)
0.14
(−1.39
to
1.68)
Body
mass
(kg)
79.91
(17.10)
80.05
(16.60)
0.14
(−1.07
to
1.22)
Height
(m)
1.68
(0.97)
1.68
(0.98)
0.002
(−1.37
to
1.86)
Body
mass
index
27.85
(4.74)
28.03
(4.84)
0.18
(−0.95
to
1.03)
Sex
(female/male)
162/130
162/130
N.A.
K --- L
grade N.A.
0
129
129
N.A.
1
40
40
N.A.
2
88
88
N.A.
3
35
35
N.A.
Performance-based
function
measures
20
m
walk
(m/s)
1.34
(0.19)
1.34
(0.21)
−0.008
(−0.04
to
0.02)
Repeated
chair-stand
(stands/s)
0.47
(0.18)
0.48
(0.18)
0.008
(−0.02
to
0.03)
Patient-reported
measures
KOOS-SRF
78.76
(22.50) 69.88
(26.82) −8.88
(−12.69
to
−5.08)*
KOOS-pain
86.75
(15.94) 84.02
(16.33) −2.73
(−4.41
to
−1.05)*
KOOS-QOL
75.98
(20.30)
67.33
(21.85)
−8.64
(−11.87
to
−5.27)*
Abbreviations:
KOOS-SRF,
knee
outcome
in
osteoarthritis
survey
sport
and
recreational
function;
KOOS-QOL,
knee
outcome
in
osteoarthri-
tis
survey
quality
of
life.
*Represents
p
<
0.05.
on
the
dominant
leg,
177
(49%)
of
participants
had
crepitus
on
the
non-dominant
leg
and
six
(2%)
were
ambidextrous.
The
mean
age
was
60.3
(8.9)
years
with
a
mean
BMI
of
28.93
(4.84),
236
(65%)
were
women,
156
(43%)
had
KL
grade
0,
43
(12%)
had
KL
grade
1,
111
(31%)
had
KL
grade
2
and
51
(14%)
had
KL
3
and
no
participant
had
KL
grade
4.
Findings
demonstrated
that
self-reported
function
was
lower
in
the
limb
with
crepitus
(15%;
trivial
effect
=
0.09)
but
no
limb
differences
were
detected
for
knee
extensor
or
flexor
strength
and
knee-related
pain
(Table
2).
Discussion
Our
findings
indicate
that
individuals
with
knee
OA
present-
ing
knee
crepitus
have
slightly
lower
self-reported
function,
quality
of
life
and
higher
pain
compared
to
individuals
with
knee
OA
without
crepitus.
However,
all
comparisons
presented
small
or
trivial
effect
sizes.
In
addition,
the
pres-
ence
of
knee
crepitus
did
not
influence
performance-based
function
tests
such
as
walking
or
sit-stand
tasks
and
knee
strength
in
individuals
with
knee
OA.
Due
to
the
small
effect
sizes
and
between-groups
dif-
ferences,
our
findings
suggest
that
the
presence
of
crepitus
on
self-reported
function
and
knee-related
quality
of
life
or
pain
may
be
limited.
It
is
important
to
note
that
even
though
the
p
values
were
frequently
significant,
the
between-
groups
differences
were
small
ranging
from
3
to
15%.
Despite
previous
reports
that
knee
crepitus
is
a
risk
factor
for
indi-
viduals
with
knee
OA14 and
associated
with
radiographic
lesions,3knee
crepitus
seems
not
to
be
detrimental
to
the
current
clinical
presentation
of
individuals
with
knee
OA.
In
both
designs
(case-control
and
within-subject),
we
observed
lower
self-reported
function
in
the
presence
of
crepitus,
but
no
difference
in
objective
function
(knee
strength
or
performance-based
tests).
We
speculate
that
these
findings
might
be
explained
by
the
negative
beliefs
individuals
with
knee
pain
have
regarding
knee
crepitus.22,24
Many
individuals
become
fearful
and
insecure
of
the
noise
related
to
crepitus
and
might
end
with
the
belief
that
their
condition
is
actually
worse
than
it
really
is.24 A
common
concern
of
patients
in
the
clinical
setting
is
about
the
meaning
and
importance
of
knee
crepitus.22
There
is
no
clear
evidence
regarding
the
source
of
the
noise,
however,
a
large
amount
of
asymptomatic
indi-
viduals
present
knee
crepitus.16,24 Therefore,
educating
and
reassuring
the
patients
by
explaining
them
that
knee
crepitus
is
not
aggravating
their
condition
seems
to
be
the
best
avenue
to
avoid
negative
beliefs.
This
is
important
as
our
findings
suggest
that
knee
crepitus
may
have
a
negative
effect
on
participants
health-related
perception.
Cross-sectionally,
knee
crepitus
was
associated
with
lower
self-reported
function
and
knee-related
quality
of
life
(small
or
trivial
effect).
However,
at
long
term
(4
years),
the
presence
of
knee
crepitus
was
not
associated
with
lower
physical
function
nor
poorer
quality
of
life
in
individuals
with
knee
OA.19 Even
so,
it
is
important
to
note
that
in
a
spe-
cific
subgroup
with
preexisting
tibiofemoral
radiographic
OA
and
without
frequent
knee
pain,
self-reported
crepitus
was
found
to
be
a
predictor
of
knee
OA.14 Further
studies
should
investigate
if
there
is
a
difference
between
self-reported
crepitus
and
objective
measures
of
crepitus
as
predictors
of
future
knee
OA.

Please
cite
this
article
in
press
as:
Pazzinatto
MF,
et
al.
What
are
the
clinical
implications
of
knee
crepitus
to
individuals
with
knee
osteoarthritis?
An
observational
study
with
data
from
the
Osteoarthritis
Initiative.
Braz
J
Phys
Ther.
2018,
https://doi.org/10.1016/j.bjpt.2018.11.001
ARTICLE IN PRESS
+Model
BJPT-177;
No.
of
Pages
6
Clinical
implications
of
crepitus
in
knee
osteoarthritis
5
Table
2
Limb-specific
characteristics
of
individuals
with
knee
osteoarthritis
presenting
crepitus
in
one
knee
(within-subject
design).
Variable
No
crepitus
knee
(n
=
361)
Crepitus
knee
(n
=
361)
Mean
difference
(95%
confidence
interval)
Demographics
K-L
grade
0
156
156
N.A.
1
43
43
N.A.
2
111
111
N.A.
3
51
51
N.A.
Strength
measures
Knee
extensor
torque
(N/kg)
4.14
(6.76)
4.12
(7.37)
−0.02
(−9.05
to
6.03)
Knee
flexor
torque
(N/kg)
1.75
(0.80)
1.71
(0.78)
−0.04
(−5.25
to
1.74)
Limb-specific
function
measures
WOMAC-physical
function
7.00
(9.39)
8.24
(10.47)
1.24
(0.36
to
2.12)*
WOMAC-pain
2.13
(2.91)
2.40
(3.11)
0.27
(−0.03
to
0.58)
Abbreviation:
WOMAC,
Western
Ontario
and
McMaster
Universities.
*Represents
p
<
0.05.
Our
findings
that
crepitus
does
not
have
any
impact
on
knee
strength,
objective
function
and
pain
of
individuals
with
knee
OA
are
in
accordance
with
recent
reports.17,18
De
Oliveira
Silva
et
al.
reported
that
crepitus
did
not
influence
knee
extensor
strength,
objective
function,
psy-
chological
factors
neither
is
associated
with
pain
in
young
individuals
with
knee
pain.17,18 Commonly,
people
associate
the
presence
of
crepitus
with
the
need
of
future
total
knee
replacement,22 however,
Pazzinatto
et
al.
investigated
a
large
cohort
and
did
not
find
any
association
within
a
3
years
period.19 According
to
previous
research,22 crepitus
is
poorly
understood
and
affects
negatively
patient’s
beliefs,
altering
movement
pattern
in
an
attempt
to
not
hear
the
noise
and
can
be
responsible
for
the
lack
of
adherence
to
exercise
therapy.22 Thus,
further
education
about
crepitus
should
be
tested
as
a
component
of
knee
OA
treatment
in
order
to
educate
patients
that
knee
crepitus
does
not
affect
objec-
tive
physical
function
or
knee
strength.
Additionally,
what
still
remains
unclear
is
the
potential
influence
of
evidence-
based
treatments
(e.g.
bracing,
exercise,
diet)15 on
knee
crepitus.
Study
limitations
and
future
research
We
evaluated
only
individuals
with
knee
OA
or
at
high
risk
of
developing
knee
OA,
therefore,
the
first
limitation
is
the
lack
of
a
group
with
no
knee
OA
which
prevents
us
from
drawing
broader
conclusions
for
the
importance
of
crepitus
in
the
general
asymptomatic
population.
Secondly,
the
lack
of
a
group
with
severe
knee
OA
(KL
grade
4)
prevented
testing
if
function
is
lower
among
those
with
end
stage
knee
OA.
Thirdly,
despite
the
high
prevalence
of
patellofemoral
OA
in
people
older
than
30
years,13 the
KL
grade
of
the
OAI
was
not
used
to
evaluate
the
patellofemoral
joint.
The
large
sample
size
may
limit
selection
bias,
however,
at
the
same
time,
spurious
statistically
significant
findings
(type
I
error)
could
be
present.7
Future
research
should
address
these
limitations
by
including
a
control
group
and
performing
a
longitudinal
follow-up.
A
longitudinal
study
can
determine
if
the
pres-
ence
of
knee
crepitus
is
associated
with
a
quicker
functional
decline
in
individuals
with
established
disease
or
associated
with
development
of
knee
OA
in
healthy
individuals.
Also,
based
on
our
findings
further
research
could
investigate
the
effect
of
education
about
crepitus
on
patient
self-reported
outcomes.
Conclusion
The
presence
of
knee
crepitus
in
individuals
with
knee
OA
indicates
lower
self-reported
function,
knee-related
qual-
ity
of
life
and
higher
pain
that
are
of
small
or
trivial
effect
sizes
with
limited
clinical
importance.
Moreover,
the
pres-
ence
of
knee
crepitus
is
not
related
with
deficits
in
objective
function
and
knee
extensor
or
flexor
strength.
Funding
source
The
authors
would
like
to
acknowledge
the
Sao
Paulo
Research
Foundation
(scholarships
process
numbers:
2015/10631-3
and
2015/11534-1).
The
financial
sponsor
played
no
role
in
the
design,
execution,
analysis
and
interpretation
of
data,
or
writing
of
the
study.
Conflicts
of
interest
The
authors
declare
no
conflict
of
interest.
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Please
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as:
Pazzinatto
MF,
et
al.
What
are
the
clinical
implications
of
knee
crepitus
to
individuals
with
knee
osteoarthritis?
An
observational
study
with
data
from
the
Osteoarthritis
Initiative.
Braz
J
Phys
Ther.
2018,
https://doi.org/10.1016/j.bjpt.2018.11.001
ARTICLE IN PRESS
+Model
BJPT-177;
No.
of
Pages
6
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