LUBRICATION
WITHIN
C. H. BARNETT
From
the
and
Department
of Anatomy
St Thomas’s
For
“
centuries
a proper
it has
MacConaill
proposed
of Osborne
and Jones
hydrodynamic
been
. . . for
Fluid
that
A. F.
assumed
lubricating
the
theory
COBBOLD,
and
Hospital
that
the
LIVING
the
LONDON,
Sherrington
Medical
fluid
of Physiology,
London
is, in William
contiguous
of hydrodynamic
ENGLAND
School
School,
synovial
Two
JOINTS
Hunter’s
Surfaces
lubrication,
words
(1743),
of a joint.
“
associated
In
with
1932
the
name
Reynolds,
could
account
for the presence
of fluid between
the articular
surfaces,
in 1936 carried
out experiments
on human
and animal
joints
which
suggested
that
lubrication
did indeed
obtain
within
synovial
joints,
at least during
some phases
of movement.
In recent
years,
however,
Charnley
(1959,
1960) has expressed
consisting
of articular
cartilage
impregnated
with synovial
fluid,
film ofthe
fluid and that their great freedom
ofmovement
depends
Like
joints
Jones,
and
has experimented
that at the human
of friction-that
to slide
the
“
Charnley
has found
coefficient
force
the view that joint surfaces,
are not separated
by a thick
on
boundary
lubrication.”
one
W
surface
acting
velocity
friction
is, the
upon
through
of
the
is believed
force
other,
F, required
divided
them-is
movement.
on excised
ankle the
by the
independent
Since
to increase
the
with
of
force
velocity
of
when
a thick fluid film intervenes
between
two surfaces,
Charnley’s
results
apparently
indicate
the existence
of boundary
lubrication
conditions,
in which
friction
is stated
to be independent
of the velocity
of movement.
features
He has
of
synovial
reciprocating
further
suggested
joints,
in
particular
the
large
movement
and
that
to which
they are subjected,
favour
the
that their
remarkable
mobility
depends
dary lubrication
of the synovial
I
FIG.
Apparatus
within
joint
for measuring
the
distal
is made
exert
the force of friction
interphalangeal
middle finger.
joint
to rotate
a fixed
requirement-and
which
adherent
The
effect
when
(Clemmesen
1951).
In the present
investigation
have been made
upon the friction
of movement
and the load borne.
with animal
joints
and engineering
662
hypothesis
on boun-
to the articular
only
experiments
these
cartilage.
designed
living
Wright
involve
articular
and
apparatus
to
measure
surfaces
are
Johns
(1960).
in
which
the
transverse
axis-an
unusual
and probably
unphysiological
allowance
for the tension
in the muscles
acting
on the joint,
make
even
their
pressures
between
the surfaces,
the molecules
mucosubstance
forming
a thin layer
the friction
between
those
recorded
by
However,
about
cannot
some
of the
other
they
an effort
are completely
has been
made
inactive
as judged
to overcome
within
a human
joint,
during
The results
have then been
bearings
of various
types.
THE
these
by electromyography
defects.
life, in relation
compared
with
JOURNAL
OF
BONE
Observations
to the velocity
those
obtained
AND
JOINT
SURGERY
LUBRICATION
WITHIN
MATERIALS
The
was
and
human
joint
studied
examined
in six adults
held in an adjustable
was
the
AND
distal
of both sexes
frame
so that
LIVING
METHODS
interphalangeal
joint
with consistent
the index
and
of the middle
finger
was then maintained
plane
of the
unable
to act
moved
passively
In
and
tracings
these
this
part
it was
circumstances
of the
seen
digit
finger,
which
supinated
phalanx
2
derived
from
human
finger
joints.
were fully extended
(Fig.
I). The middle
flexed to its full extent,
making
an angle
palm.
middle
______
FIG.
typical
of the
results
in all. The hand was
ring fingers
and the proximal
_____
Two
663
JOINTS
the
could
tendons
no
to be unusually
phalanx
of the middle
finger
of 80 degrees
or less with the
controlling
longer
the
be flexed
distal
or extended
phalanx
were
actively;
when
flail-like.
.\
20-
.
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=
‘S..
.
E
<
-
10
S’S
S.,
I
I
0
I
I
I
showing
units)
decline
in
the
and
The
the
anatomical
draws
proximal
basis
distally
the
amplitude-and
for
point
interphalangeal
this
joint
between
of swings.
therefore
origin
therefore
the
for the earlier
manoeuvre
of
3
relationship
the number
greater
fingers
is well
of
the
relaxes
0
44 B,
NO.
3,
AUGUST
1962
the
Note
amplitude
that
coefficient
of
(in
the rate
of
friction-is
swings.
known.
middle
the long extensor
tendon
inserts
into both middle
and
extend
the terminal
phalanx
alone
when the proximal
VOL.
I
of swings
FIG.
arbitrary
I
10203040506070
Number
Graph
I
finger
this
tendon
Extension
tendon,
of the
and
completely.
rilig
aIld
passive
On
index
flexion
the
at
dorsum
distal
phalanges,
so that it is unable
phalanx
is maintained
in full flexion.
to
664
C. H.
The
could
adjustable
frame
comfortably
end
of his middle
the
clamp
and
.
Figure
1
table.
The
his
finger
and
the
It could
bob
was
rest
mounted
nail.
swinging
contained
A
A. F.
end
of a metal
A moulded
by screws
so that
pendulum
was
battery
table
metal
off
connected
upon
which
clamp
no movement
suspended
by switching
a torch
COBBOLD
forearm.
tightened
finger
AND
at the
supinated
be set
pendulum
at a higher
was directed
into the
BARNETT
was
was
from
this
clamp
electromagnet
(M)
to
a small
bulb
subject
over
permitted
an
electric
the
fitted
the
between
as
shown
in
attached
to
the
attached
to
the
level.
This was suitably
shielded
to emit a narrow
beam
of light, which
lens of a cin#{233}-camera (C) orientated
so that the film travelled
vertically;
;i IAAAAAAAAAAAIIIA.
I jI1vvuvvvvIuv”v’..
4
FIG.
Tracing
derived
from
other
dog’s
soft
ankle
tissues
joint
(skin
50
60
and
intact).
x%
o
\‘
S.
__xo
20
#{149}S
‘0
x\
#{149}5#{149}
0
xo
‘0
4io
x’
‘x
-
#{176}
0
x
o
‘
‘
x
,
c‘
xo
0
x
_l
0
I
10
I
20
I
I
30
40
Number
FIG.
Graphs
units)
friction
ligaments.
ankle
joints
the relationship
between
the amplitude
(in arbitrary
of swings.
Note the reduced
coefficient
of
the skin has been cut away and the further
reduction
to
coefficient of friction (001 3) after division
of tendons
and
x=Skin
intact.
o=Skin
excised.
S =Ligaments
and
seven
divided.
of the light in an approximately
shown
in Figure
2. At the centre
upon which
a flat lead weight
could
apparatus
was subsequently
modified
of
of swings
5
the number
tendons
platform
The
80
showing
and
after
a constant
thus any oscillation
the film of the type
I
70
freshly
amputated
legs
horizontal
of gravity
be placed
in order
of
dogs
plane
produced
of the pendulum
to vary the
to measure
and
a tracing
on
was a small
load on the joint
surfaces.
the force of friction
in the
in a number
of
bearings,
metal
and
plastic.
The
as set out
oscillations
coefficients
offriction
were
calculated
in the appendix.
They
vary directly
and inversely
as the radius
of curvature
by a modification
of Edwards’s
as the decrease
of the articular
THE
JOURNAL
(1959)
in amplitude
of
surfaces,
as seen
OF
BONE
AND
JOINT
method,
successive
in profile.
SURGERY
LUBRICATION
comparing
large joints
the tracings
bearings
In
or
frictional
WITHIN
LIVING
665
JOINTS
shown
in the figures
the reader
come
to rest more
quickly
than
should
small
therefore
ones
that
bear in mind
that
possess
identical
properties.
OBSERVATIONS
To
upon
avoid
repetition
the
results
of each
experiment
are
recorded
and
briefly
commented
in turn.
Adult
finger
joint-All
joints
I 5 degrees
approximately
was
tested
and
amplitude
decreased
a little more
The minimum
coefficient
of friction
and
Charnley.
the
experiment
The
tracings
might
more
knee,
was
firmly
than
was
as indicating
losses
Such
Charnley
that
than
towards
similar
rapid
the
place
clamped
oscillations
carried
out on animal
was modified
to hold
2 and 3).
by Jones
near
slow
a conclusion
would
support
pointed
out an alternative
of the human
finger.
to the proximal
part
in
the end (Figs.
to that obtained
consistently
entail
more
tension
in ligaments
and other
soft
are likely to have a damping
effect only during
this hypothesis
experiments
were
Dog’s ankle joint-The
apparatus
the
at the start
00075,
which
frictional
was coming
to rest.
in joints.
However,
at the start
soft tissues
rapidly
was
be interpreted
involved
pendulum
lubrication
gave very similar
results.
The initial
angular
amplitude
the pendulum
came
to rest within
three
minutes.
The
the
start
oscillations
the theory
possibility.
as
of
the
of fluid film
Large
swings
tissues
than small swings,
and the
the initial
large swings.
To check
joints.
a dog’s
hind
limb,
amputated
The foot was fixed horizontally
of the limb so that when swung
above
and the pendulum
to and fro it moved
the
ankle joint
through
the middle
part of its normal
range.
The coefficients
of friction
again showed
reduction
towards
the end of the tracing
(Fig. 4).
The effect was in part due to tension
in the thick
skin surrounding
this joint.
Cutting
away
the
skin
reduced
the joint
had
number
the
been
of oscillations
line, indicating
movement.
This result
that
friction,
it also
the
all the
coefficient
confirmed
the
lubrication.
tissues
bearing.
Figure
was
bearing
was
“
44 B,
NO.
were
constructed
made
of
DQ
give a coefficient
VOL.
long-chain
type,
8-Tracing
3,
“
dry
bearing
of friction
AUGUST
1962
longer
the
and
that
fell
to the
velocity
at first
joints
seemed
to
around
against
points
related
the
owe
of joint
believed
free
added
8
derived
the
on a straight.
writers
their
provide
7
mobility
support
for
FIG.
Figure
7-Tracing
from
brass
bearing,
from
showing
of friction)
was much
evident.
polymers,
known
a modification
of nickel-plated
which
divided
ligaments
is plotted
(and therefore
a high coefficient
this change
in the force of friction
using
material
of 007,
and
pendulum
findings
derived
plastic
investigated
of a cylinder
no
DQ bearing.
less
bearings-Certain
been
hypothesis
FIG.
from
all tendons
of the
experiments
high rate of decline
in amplitude
the Start.
In some experiments
of the boundary
had
of his
at
Plastic
when
experimental
following
derived
less
amplitude
of friction
FIG.
6
6-Tracing
P.T.F.E.
soft
correctness
The
still
5 the
Charnley’s
proved
Figure
became
In Figure
: once
that
had
to boundary
this belief.
which
divided.
to exhibit
of the
same
phosphor-bronze
(Glacier
Metal
was
unrelated
Company
excellent
lubrication
apparatus.
A partial
oscillating
Ltd.).
to the velocity
This
in a trough
was
of movement
found
(Fig.
to
6).
666
C.
A similar
result,
with
phosphor-bronze
a constant
cylinder
BARNETT
coefficient
oscillating
the interstices
of sinter’d
copper
using
ankle
division
a dog’s
H.
after
AND
A. F. COBBOLD
of friction
0033,
upon
(Fig.
7).
of
The
the
was
obtained
polytetrafluorethylene
shape
soft
(P.T.
of the tracing
was
using
a nickel-plated
F. E.) contained
similar
within
to that
obtained
tissues.
These
derived
ricated
results
were
then
compared
with
those
from
conventional
brass
bearings
with standard
mineral
oils.
lub-
Oil-lubricated
brass bearings-Each
journal
was
a brass
cylinder
one inch in diameter
and two
and three-quarter
inches
in length,
with a hole
drilled
in it to receive
the stem of the pendulum.
The
- .3.
A
typical
tracing
den
and
throughout.
1956),
the
the
conductivity
separated
slowed
the
and
but
in
It
the
supposition
during
at each
the
end
noted,
out
seconds
to
viscosity
of
oil,
the
electrical
freely
(Fig.
the
more,
to
character
begun
film
of
the
on
tracing
It was
decided
to construct
allow
the journal
fluid for a long period.
Hydrostatic
bearings-A
taming
a cavity
(Fig. 1 1 ). This
a hydrostatic
to
oscillate
large
into which
communicated
fluids
FIG.
Graph
showing
that
has
a constant
during
the initial
coefficient
bearing
on a turbulent
bearing
was
constructed
could be fed under
by a number
of holes
of friction,
almost
until
altered,
: a thick
whetl’er
at
oscillations
a
in contact,
of electrical
thick
film
of
fluid
as the pendulum
prevailed,
as
in
after
type
of
record
the journal
was
had
obtained.
,
u
o
-
5
-
.
E
<
which
film
of
conpressure
with the
0
floating
“
brass bearing
unrelated
to velocity.
a
uniform
was
oil
10
phase
was
as
(Bow-
to
of
was not
would
8),
was as
character
fact that during
the initial floating
related
to the velocity
(Fig.
10).
friction
was
(Fig.
the
journal
of
With
journal
during
was the
the
friction
velocity
immediately
after
which
a thick
film of oil was present
only
the middle
part of each swing.
Of especial
interest
phase
of
considerations
friction
different
from
the
friction
the
the
thick
bath.
(1946).
coming
quickly
Measurements
that
a
early
partial
oil
a film or are virtually
The measurements
Tudor
depending
coefficient
of
rather
abruptly
high
of each swing,
but that
boundary
lubrication
a very
ranging
attached
confirmed
the
were
bearing
a period
or
upon
the
in
if recordings
pendulum
a brass
an
coefficient
theoretical
the
by such
lubrication.
that
the pendulum
experiments.
conductivity
that
that
at
in
journal
and its bearing
was determined
one can use this technique
to decide
and
and the
9). Then
continuously
moment
from
by Courtney-Pratt
a minute
of the tracing
altered,
rest
as in the earlier
floating
expected
portion
oscillation,
the oil-covered
bearings-For
the
greater
middle
of an
‘owever,
into
brass
several
swung
very
low as 00l6
between
the
and therefore
surfaces
stopped,
bearings
experiments
within
immersed
usually
metal
surfaces
are separated
case if there
were boundary
carried
was
some
confirmed
experiment
been
lowered
“ Floating
“
floating”
“
bearing.
Tabor
any moment
as would
be
the
a
The electrical
conductivity
of oil is a poor conductor
film
the
from
oscillated
totally
these
9
derived
brass
cylinder
bearing
I
I
10
20
“
Number
of swings
LUBRICATION
bearing
rested.
surface
Several
lubricating
and
last
upon
fluids
oils,
which
were
5 per
LIVING
JOINTS
667
a brass
cylinder
tested
including
cent
cold water
from
the
was least troublesome
WITHIN
dextran
solution
mains
supply.
The
and gave consistent
records.
In all cases the coefficient
of friction
was low and it was almost
independent
of the
velocity
(Fig.
12).
Thus a constant
coefficient
of friction
may
indicate
boundary
lubrication
but the results
ofthe experiments
using floating
brass and hydrostatic
bearings
suggest
that it may alternatively
indicate
other
forms
of lubrication
between
the
fixed
and
To
applies
study
moving
surfaces
decide
which
to synovial
the
effects
upon
the
Alteration
of
a joint
or bearing.
alternatives
decided
an
of
friction
within
of the load
surfaces-In
of a joint
of the above
joints
it was
or
alteration
a joint.
carried
by
bearing
the
the
to
load
. .
the
bearing
surfaces
of
....
.
which
are separated
at all times
by a layer of
FIG.
viscous
fluid of adequate
dimensions,
the coThe hydrostatic
efficient
of friction
decreases
as the
load
increases.
The reason
is that the friction
F is theoretically
independent
that
the
lubrication
fraction
F/W
will vary
conditions
an increase
the surfaces
Theoretically
and
raises
the friction
inversely
with
in the load
W
correspondingly
F/W
is constant
W.
causes
the friction
whatever
the
On the
a more
.
.
.
II
the
in
of the
load
other
hand,
in
intimate
contact
as one
load.
is
sheared
present
W,
so
boundary
between
upon
another.
The
results
of ten experiments
are shown
in Figures
13, 14 and 15.
The
plastic
bearings
showed
little
variation
of the coefficient
of friction
as the
.
I5
load
for the
.
the
friction
expected
\
;.
did
to rise slightly
\
.\
‘S
and
the
oil-
I0
2 0
Number
30
I
I
4 0
5 0
of swings
the
beyond
unexplained
floating
brass
hydrostatic
bearings
showed
coefficients
of friction
which
declined
as the load
increased,
in
accordance
with
theory
(Fig.
14).
The human
fingerjoint
and the dog’s
ankle
yielded
graphs
that bear a close
resemblance
floating
___________________________________
I
I
I
I
an
The
bearings
.\.
<
0
nor
value,
observation.
I F%
#{149}1 U’,J
=
5
changed,
lubricated
brass
bearings
(Fig.
13).
In many
of these
experiments
there
was a tendency
with
large
weights
(Fig.
and
to those derived
hydrostatic
15).
FIG.
Graph
has
from the
bearings
showing
a
that
constant
unrelated
12
a hydrostatic
coefficient
to velocity.
bearing
of
friction,
668
C.
H.
BARNETT
AND
A.
F.
COBBOLD
-
-08
J4
-
-
07
#{149}---.‘‘
I_
‘06
300
I
I
500
I
I
700
I
900
I
1100
w (Gms.)
.034
-
.------.--.--------.
“032
I
I
I
300
I
500
I
1
700
1
1
900
1100
W(Gms)
-17
-
#{149}15
-
#{149}13
-
1 I
#{149}-
-.---
-
I
300
I
-
-
I
I
500
1
()
in a DQ
brass
weight
(W)
I
1100
ms.)
13
plastic
bearing
I
900
w
of friction
oil-lubricated
1
700
FIG.
The coefficients
(centre)
and an
-.
-
bearing
(bottom)
(above),
; there
a P.T.F.E.
is no reduction
bearing
as the
is increased.
THE
JOURNAL
OF BONE
AND
JOINT
SURGERY
LUBRICATION
WITHIN
LIVING
JOINTS
669
DISCUSSION
The
objections
lubricated
raised
by thick
by Charnley
films
and
of synovial
fluid
his co-workers
between
the
(1959)
surfaces
to the
may
theory
be listed
that
joints
are
as follows.
#{149}03
‘SN
-
.
___
‘OI
1
0
600
1
I
1
800
I
1000
I
I
1
1200
1400
W(Gms.)
#{149}04
-.
-.---- -
.
\
‘03
Al
\
I
\
‘02
.
I
‘01
600
I
I
I
800
I
1000
w(G
coefficients
hydrostatic
of
bearing
()
friction
(below);
in
a
“
the coefficients
I
1
1400
ms.)
14
FIG.
The
I
1200
floating
“
brass bearing
(above)
are diminished
as the weight
and
a
(W)
is
increased.
I)
animal
“
statement
VOL.
The
joint
44 B,
gross
lack
of congruity
“
is cited
from
another
part
AUGUST
1962
NO.
3,
as evidence
of the
for
same
according
to engineering
boundary
lubrication.
paper
:
“
There
standards
This
can
be little
may
doubt
encountered
be contrasted
that
these
in an
with
resilient
a
670
C.
surfaces
are
intimately
applied
loads.”
It
is reasonable
to
freely
moving
male
which
it is applied,
under
elastic
pressure.
materials.
‘018
BARNETT
to each
suggest
articular
the
H.
other
original
A.
F. COBBOLD
over
the
a compromise
surface
Synovial
AND
is
large
joints
slightly
more
discrepancy
would
whole
be
especially
these
than
partly,
but
analogous
when
statements,
curved
being
then
area
between
the
not
carrying
namely
female
completely,
to engineering
that
a
surface
to
obliterated
bearings
made
of
-
\
‘10
-
-\
\
09
016
\
-
-
\
-
014
-
08
\
-
-
‘a
\
-
-
07
012
-
‘U
‘06
#{149}0i0
-
05
\
008
I
I
300
1
500
I
I
700
‘04
lL
900
,‘..
1100
w (Gms.)
FIG.
The minimum
coefficients
finger (left)
. =unskinned,
and
15
of friction
in
a
dog’s
:
in a human
ankle
(right):
o==skinned,
x=ligaments
and
divided.
The coefficients
are diminished
as the weight (W) is increased.
tendons
._.......l..
0l
500
300
700
1100
900
W(G ms)
2) Charnley
states
:
The
“
coefficient
of friction
of articular
altered
when the sliding
surfaces
are wiped free of visible
in another
part of the paper
it is pointed
out that when
heavy
load,
surfaces,”
be made
a fluid
so that,
lubrication
is very small
methods
temperature
that
surfaces
the
that,
forces
to allow
in
himself
wet
an
with
“
and
“
excised
synovial
readily
dry
“
human
. . .
velocity
admits,
Moreover,
complicating
local pressure
must
ankle
of friction
separated
(1959)
the
need
by a thick
has
building
calculated
up ofa
not
factors
affect the
vary
film
of
that
with
fluid,
synovial
hydrodynamic
However,
under
will
no true
be
expressed
from
experimental
the
a
joint
comparison
can
surfaces.
joint,
“
incompatible
is
significantly
wetting
by synovial
fluid.”
a fresh joint
is compressed
fluid
articular
is not
“
the
constancy
with
the
is open to question
; it is certainly
no proofofboundary
and within
a narrow
range
of velocities
little variation
“
and
are
“
decreasing
used.
bearings.
4) Tanner
shear
fresh
view
with
identical
as Charnley
between
3) The
friction
apparently
cartilage
such
results.
of the
coefficient
hydrodynamic
of
theory
of
lubrication.
The coefficient
could
be detected
by the
as the dependence
of viscosity
upon
In any case it has been demonstrated
the
velocity
as
in the
fluid
film,
even
is not
and
ThE
when
floating
“
the
“
viscous
Tanner
JOURNAL
moving
brass
and
enough
and
OF
and
fixed
hydrostatic
at high
Edwards
(1959)
BONE
JOINT
AND
the
rates
found
SURGERY
of
LUBRICATION
that
synovial
fluid
calculations
the
during
in addition
is
ineffective
make
no allowance
reversal
of direction
the
interval
nature
of
those
of the
joint
constructed
metal
it seems
used
these
that
standard
produced
at
the
of
greater;
surfaces
journal
and
Edwards’s
between
the
If a perfectly
prove
very
surface
A
two
dry
Charnley,
under
more
pressure.
elaborate
may
and
pressure,
by the
oil
stepped
upon,
imitation
of
used
Edwards
for
be
some
weight
building
pores
below
that
for fluid to
the
periphery
of an
has
1927).
soaked
when
is the slipperiness
the inner surface
cartilage
and
up of a film
in from
and Deeley
of limestone
oozing
artificial
of
film could
be understood.
of fluid is seen in the stone-
multiple
of the
articular
the
dragged
(Archbutt
pieces
from
have
from
in the
1960),
a thickness
if it were possible
of a persistent
fluid
for local production
because
and
model
markedly
(1947).
account
seeping
differ
Bauer
could
than
which
perspex
and
rather
1953)
The
joints,
and though
type
of movement
and
and McCutchen
1942).
However,
the presence
a mechanism
The
viscosity
Stanier
be inaccurate.
or the
Tanner
principles
surfaces
(Lewis
(Schnurmann
maximal
when
(the
of
Peabody
surfaces.
A more
familiar
example
skin is placed
on the pavement
with
slippery
a joint.
surfaces
than ifthe
moving
one were
account
has been taken
of the elastic,
model
Rossmeisl,
by
is lubricated
in.)
properties
lined bushes
sometimes
used in engineering
practice
surface
is made
of white metal
in which
are embedded
rotating
representing
is reciprocating
see Osgton
(00l
physical
Robertson,
regions
that are in contact,
A typical
example
of such
model
movement
between
articular
Moreover,
no
hydrodynamic
site
much
the
the
objections
the
rolling
movement
present
at many
Davies
and
MacConaill
1961),
this
in Tanner
only 0#{149}5
//( thick
between
the
which
is theoretically
desirable
be
very
between
cartilage,
by Ropes,
that
671
JOINTS
a metal
fact
being
the so-called
(Barnett,
articular
Nevertheless
the
the
produces
a lower rate ofshear
about
a fixed stationary
axis.
spongy
LIVING
lubricating
for
suggested
makes
no allowance
for
the term
is a misnomer
certainly
rotating
in
WITHIN
The female
in oil. The
contact
is made
of a banana
facing
upwards
oily
been
substance
skin.
it will
from
suggested
and
its
tested
experimentally
by McCutchen
(1959).
Each bearing
surface
is made up ofa slab of closed-cell
sponge
rubber
soaked
in a slippery
fluid (soapy
water)
and covered
by stretched
sausage
casing.
Two such surfaces
were found
to slide upon
one another
with great
freedom,
the coefficient
being 00l
or less at first; the
weeping
offluid
through
the porous
wall supplies
liquid
to maintain
the film for forty
minutes
before
the coefficient
exceeds
003.
to a recent
paper
by .McCutchen
(1962),
it would
be difficult
to express
all the
offriction
enough
According
“
synovial
fluid
contained
within
pressure
for many
hours,
One of the writers
the
presence
out
that in fact
mucosubstance
the
a
joint.
the
a condition
previously
of hydrodynamic
This
suggested
It is also
the
“
layer
likened
not
carried
lubrication
of
within
joints
is present
within
the
fluid
“
in the lubrication
movement)
the
except
that
the
life.
which
(Barnett
present
writers
consider
effect
work
in the engineering
pressures
on the viscosity
VOL.
44 B,
3,
AUGUST
1962
were
after
in the
ofjoints
cartilage
continuous
assumed
to confirm
Charnley
these
was that
in maintaining
contained
“
even
1956).
joint
has
pointed
hyaluronic
acid,
the mobility
of
cavity,
where,
as
because
ofits viscous
properties.
(Ekholm
and Norb#{228}ck 1951).
on the surfaces
ofthe
articular
cartilage.
In these
to sheets
of sintered
copper
(a sponge-like
for.
Modern
of high
NO.
cartilage
of any joint in which
(because
of an exceptional
load and
film of fluid had temporarily
broken
down,
by constituting
impregnated
with one of the new long-chain
plastic
(Barnett
1956).
This idea does not differ substantially
called
articular
obtaining
during
out experiments
it can assist
weeping
lubrication
within
the interstices
of the articular
Here it could
help
unduly
prolonged
a boundary
can
be
interstices
only valid conclusion
to be drawn
from
present
in synovial
fluid, is of importance
substance
above,
found
“
that
this
materials
from
boundary
field, in which
the
of lubricant
fluids
the
circumstancesjoint
preparation
of
the
surfaces
metal)
such as polytetrafluorethylene”
opinion
now held by Charnley
lubrication
is not
deformation
of the surfaces
are both taken into account,
commonly
and the
suggests
672
c. H. BARNETT
that,
in
hydrodynamic
less frequently
bearings,
lubrication
A.
F. COBBOLD
lubrication
occurs
much
than
is usually
supposed
“
much
AND
more
frequently
(Archard
and
“
there
are
many
factors
that could
assist
the formation
of stable
between
the articular
surfaces.
Especially
in joints
used for locomotion,
of pressure-bearing
and non-pressure-bearing
phases.
During
the latter,
fluid
can form
between
the articular
surfaces,
temporarily
sustaining
phase,
pressures,
mechanism.
the region
both
The
fact
surfaces-not
bearings
(Barnett,
from
both
efficient
that
merely
Davies
surfaces
than
on
that
and
(1932,
“
ofmaximal
moving
pressure
one-is
MacConaill
movement
envisaged
MacConaill
in a manner
reminiscent
of a floating
bearing.
direct
contact
will be minimised
by McCutchen’s
the
throughout
in the
classical
has
suggested
1950)
boundary
1961).
In
films of synovial
fluid
there is an alternation
a thick film of synovial
the overlying
bones
joints
during
the pressure-bearing
film is dispersed
by high
and
Kirk
is constantly
an important
1961),
and
of the
joint.
leads
to
Such
hydrodynamic
If the thick
weeping
“
changing
its position
difference
between
the
expression
ready
a mechanism
on
joints
and
of
would
fluid
be more
theory.
functions
for
various
intra-articular
structures
in
conformity
with his opinion
that hydrodynamic
lubrication
prevails
within
joints.
Though
the film of fluid may persist
as a result
of the weeping
mechanism
postulated
by McCutchen,
MacConaill’s
suggestions
still have great relevance.
It would
be expected
that the form of any
intra-articular
structure is such as to favour the maintenance
of a fluid film even if, as now
appears, the source
thirty years ago.
of the fluid
1.
a device
between
the surfaces
is other
than
that
assumed
by MacConaill
SUMMARY
By
the
use
uninfluenced
articular
2.
3.
by muscle
that
allows
activity,
the
movement
coefficient
force
of
friction
developing
rises
in the
Measurements
four
as
ligaments
have
dog and within
hydrostatic).
also
the
range
and
the
been
types
of
moving
“
a human
has
surfaces,
rather
made
of
finger
been
joint
to
determined
floating
though
indebted
are
to
on
W.
Dr
surrounding
forces
of
bearings
take
place
between
living
depending
occasions
Cochrane
friction
(plastic,
because
of
the
wholly
for
great
within
the
ankle
oil-lubricated,
“
boundary
advice
or in part
freedom
weeping
joint
for
on
writing
may
the
of the
floating
“
boundary
of movement
lubrication,”
conditions
and
tensicn
the joint.
and bearings
it has been shown
that joints
a film of fluid is maintained
between
the
joints
normally
owe their
that
has been
termed
lubrication,”
We
bearings
is increased,
tissues
the
of reciprocating
than
It is suggested
that
fluid
film lubrication
movement
soft
4. By altering
the load borne
by the joints
in their behaviour
those
bearings
in which
5.
of
of
of friction
surfaces.
The
then
of
and
“
resemble
fixed and
lubrication.
to a special
supplemented
type
by
prevail.
appendix
to this
paper.
REFERENCES
J. F.,
ARCHARD,
261-A,
and
L., and
ARCHBUTT,
Griffin
DEELEY,
BARNETF,
C.
H.
(1956):
C.
H.,
DAVIES,
& Co.
Ltd.
Green
F. P.,
CHARNLEY,
Institution
CHARNLEY,
Annals
T.
(1961):
Lubrication
at
Point
Proceedings
Contacts.
of the Royal
Society,
R.
Lubrication
M. (1927):
andLubricants.
Fifth
edition,
p. 154.
Surgery,
38-B,
London:
Charles
& Co.
BARNETT,
BOWDEN,
M.
KIRK,
532.
and
Wear
D.
TABOR,
J. (1959):
The
of the
The
Rheumatic
Tear
and
D.
(1956):
in Joints.
MACCONAILL,
Lubrication
of Mechanical
J. (1960):
and
V.,
Friction
of
Animal
Journal
M.
ofBone
andJoint
A. (I 961 ): Svnovial
andLubrication,
Joints.
p.
In
107.
Joints,
p. 1 87.
London:
Symposium
567.
London
: Longmans,
Methuen.
on Biomechanics,
p. 12.
London:
Engineers.
Lubrication
Diseases,
ofAnimal
19,
Joints
in Relation
to Surgical
Reconstruction
by Arthroplasty.
10.
THE
JOURNAL
OF
BONE
AND
JOINT
SURGERY
LUBRICATION
S. (1 95 1 ) : Some
CLEMMESEN,
of Physcial
COURTNEY-PRATT,
J. S.,
Bowden,
F. P., and
on
Muscle
Tone.
LIVING
JOINTS
Proceedings
of
673
the
Ro.i’al
Society
of
(Section
Medicine
44, 637.
and
G.
TUDOR,
Tabor,
D.,
K.
pp.
Derivation
F. J. (1959):
EDWARDS,
Studies
Medicine),
WITHIN
(1946)
: Summarised
248-257.
ofan
Oxford
Expression
in
The
: University
for Friction
Friction
and
Lubrication
of
by
Solids,
Press.
Coefficient.
Appendix
to paper
III
by Charnley,
J. (1959).
R.,
EKHOLM,
and
Scandinai’ica,
W.
HUNTER,
the
(1743):
Royal
Of
P.
LEwIS,
R.,
Joint
Knee
and
A.
M.
Journal
W.
C.
(1950):
and
The
Joint
Sponge-hydrostatic
(1962):
The
W.
and
(1942):
B.,
for
Transactions
of
Weeping
Lubrication
in
Animal
Calculation
Joints.
185, 920.
Nature,
with
Special
Reference
to
the
66, 210.
Joints.
III.
The
Law,
Physiological
Synovial
Fluid
Function
PEABODY,
R.
196, 700.
“
of Frictional
Traces
184,
5, I.
Nature,
Wear,
Joints.
and
its Assistants.
1,284.
of Hyaluronic
119, 244.
ofPhysiology,
E. C.,
“
Bearings.
of Animal
Supplement
13,
Mammalian
Weeping
Journal
ROSSMEISL,
Amonton’s
I. (1959):
B., and
BAUER,
Contact,
and
Acid
W.
in Synovial
(1947):
Fluid;
Synovial
Experiments
Fluid
on Adhesion.
235.
of the
Shear
Rate
in the
(1959):
The
Lubricating
Hip
Joint
Lubricant.
IV
Appendix
to paper
by
J. (1959)
R. I., and
Properties
of Synovial
Fluid.
V to paper
Appendix
J. (1959).
V., and
Joints.
F. J.
EDWARDS,
by Charnley,
WRIGHT,
The
Properties.
V.
Pkvsics,
Charnley,
TANNER,
and
Scandinavica,
ofApplied
R.
Aca’a
Functions.
Philosophical
Fibrocartilages,
and
Properties
J. E. (1953):
W.
of
ofBones
Frictional
Lubricant
Medica
R.
Journal
and
ROBERTSON,
Acta
SCHNURMANN,
TANNER,
STANIER,
Elastic
M. W.,
and
244.
32-B,
(1959):
Mucin.
Changes
Cartilages.
Evidence
Lubrication
Movements
Surgery,
C.
RoPES,
Articulating
of Intra-articular
Journal
ofAnatomy,
Joints.
C. W.
G.,
of
Experimental
(1960):
MCCUTCHEN,
A.
Articular
i, 1,043.
Function
MCCUTCHEN,
Viscous,
Diseases
(1959):
W.
The
Radio-Ulnar
A.
of Bone
OGSTON,
Between
1,285.
(1932):
Inferior
MACCONAILL,
Relationship
Lancet,
C.
MCCUTCHEN,
M.
the
and
Lubrication.
184,
and
MACCONAILL,
Structure
MCCUTCHEN,
Nature,
P. R.,
LEWIS,
On
81.
42, 514.
and
Joints.
21,
the
Society,
E. S. (1936):
JoNES,
B. (1951):
NORBACK,
Orthopaedica
JOHNS,
Bulletin
R.
of the
J. (1960):
Johns
Physical
Hopkins
Factors
Hospital,
Concerned
106,
with
the
Stiffness
of
Normal
and
Diseased
215.
APPENDIX
(Modification
Assume
point
bob
B (Fig.
of
of Edwards’s
pendulum
of
method
for calculating
L
from
length
swings
coefficients
point
of friction)
A across
midline
and
returns
to
16).
Then
a’=c(2L-c)
=2cL
(since
c is small
compared
with
L)
a’
...
c=2L
.
b’
.
Similarly
...
Let weight
of bob
d=
2L
c-d=--
be W.
fa’-b2
Then
potential
As bob
swing
and
VOL.
swings
(.....
across
+b)
lost =W(c
midline
on return (Fig.
-d)=W
from
distance
travelled
=2(a
Let total
distance
travelled
by articular
.
44 B,
NO.
3,
AUGUST
1962
(,--
A and
back
to B, it travels
distance
on forward
(a±ii.)
I 7).
Total
.
.
energy
+b).
surface
of distal
phalanx
in a to-and-fro
swing
=
x.
674
C. H. BARNETT
x
Then
2(ab)
L
(approximately).
of friction
at distal
=
Let force
.
Then
.
frictional
work
AND
interphalangeal
A.
F. COBBOLD
jointF.
2FR(a±b)
done=Fx=-
L
A
A
B
16
FIG.
Equating
this
with
FIG.
potential
energy
17
lost,
2FR(a+b)
W(a’-b2)
L
2L
...
______
4R
.
.
F
..
Coefficient
of friction
=
-
a-b
4R
(The distance
lateral radiographs.)
(a -b)
can
be
measured
on
the
tracings
and
THE
R determined
JOURNAL
approximately
OF BONE
AND
JOINT
from
SURGERY