The tibial plateau. - morbid anatomy. In this prospective study, the medial tibial plateaux excised during. 46 unicompartmental arthroplasties for primary osteo-.
ANTEROMEDIAL
OSTEOARTHRITIS
S. H. WHITE,
From
Medial
collected
tibial
plateaux
P. F. LUDKOWSKI,
the Nuffield
excised
and photographed.
during
The anterior
46
diagnosed
from
unicompartmental
Centre,
tomy
in the
varus
knees
lateral
unicompartmental
arthroplasties
ligament was intact in alljoints. on the plateau and the posterior cartilage
its
anatomical
arthroplasty
treatment
rather
of elderly
(Goodfellow
as surface
features
render
in this study of performing than
tibial
people
et al 1988).
with
We
could
osteo-
painful
well as the erosions.
extent
and
location
were
case the cartilage The site of the was observed
METHODS plateau
the
AND morbid
-
cartilage
S. H. White, B Med J. W. Goodfellow, Surgeon Nuffield Orthopaedic OX3 7LD, England.
knee
was
Sci, FRCS, MS.
FRCS,
Centre,
© 1991 British 0301-620X/91/4159 J Bone Joint Surg
should
be sent
eroded
in
its
at least
full
contra-indication
were
for
treatment
down
sometimes
valgus 4) The
thickness.
and
by
to the
subchondral
even
Fibrillation localised
was
areas
not
a
of ulceration
accepted.
3) Anteroposterior
radiographs
showed anterior
correction cruciate
anatomy.
in the
In this
medial
prospective
compartment
of
Senior Orthopaedic Registrar Honorary Consultant Orthopaedic Windmill
Road,
Central
Headington,
Road,
to Mr S. H. White.
Editorial Society ofBone $2.00 [Br] 1991 ; 73-B : 582-6.
and
Joint
descriptive
divided
FINDINGS
P. F. Ludkowski, MD, Orthopaedic Surgeon Orthopaedic Associates, S.C., 1300 East Heights, Illinois 60005, USA. Correspondence
suitable
of the
knee
stressed
into
of the varus deformity. ligament was intact as observed
at surgery.
study, the medial tibial plateaux excised during 46 unicompartmental arthroplasties for primary osteoarthritis were collected and photographed. All the joints fulfilled our anatomical criteria for medial unicompartmental arthroplasty: articular
it
bone and usually beyond (stages 2, 3 and 4, Ahlb#{228}ck 1968). 2) The articular cartilage in the lateral compartment was preserved
observe
of
the
For
582
osteoarthritis
In every
was intact. explain why varus deformity and had not become fixed.
taken together was correctable
the exact site and extent of the joint erosions and relate them to the state of the cruciate and collateral ligaments. The physical signs of anteromedial osteoarthritis can be explained if the state of the ligaments are
1) The
for
cruciate
radiographs;
specimens described because of our practice
unicompartmental
tibial
Oxford
arthroplasty.
The pathological became available
The
KNEE
Failure of the anterior cruciate ligament may allow the erosion to extend posteriorly, producing fixed deformity and leading to degeneration of the lateral compartment. Anteromedial osteoarthritis is a distinct dlinicopathological entity; its radiographic features enable it to
yams
considered articular
THE
J. W. GOODFELLOW
Orthopaedic
and bone erosion was centred anteriorly lesion and the intact state of the cruciate ligaments only in the extended knee, and why the deformity
be
OF
Surgery
Oxford
Arlington
purposes
transversely
front
to
often tenor
involved. zone, and
(Fig.
back.
into The
the
four
tibial
zones,
anterocentral
zone
The lesion seldom never reached the
plateau
A, B, C and (B)
was
D, from was
extended posteriorjoint
most
to the posmargin
1). The
site
is shown
of the
in Figure
deepest
point
2 ; in no case
of erosion did
in each
it lie behind
point (B/C) of the tibial plateau. Lateral radiographs. In all cases,
knee
the
pre-operative
mid-
lateral
radiographs were available and were studied independently of the pathological specimens to see how accurately they revealed the site and extent of the bone erosions. The medial tibial plateau was distinguished from the lateral by using the signs described by Jacobsen (1981). The site ofthe deepest point ofthe erosion correlated well
with
case
differed
Clinical observed: 1) The application
the
signs. varus
morbid by more
Two
anatomical than
zone
physical
deformity
was
of manual
stress
THE
localisation,
one
JOURNAL
(Fig.
signs
and
were
consistently
correctable
in every
case
into
(see
Sb).
valgus
OF BONE
in no
2).
AND
Fig.
JOINT
SURGERY
by
ANTEROMEDIAL
Fig.
2) Varus but
deformity
diminished
OSTEOARTHRITIS
features in the
case.
was present
in the extended
during
flexion
Several
of the clinical
of anteromedial following case.
taken in 1975 when suffering discomfort
and
was
posture
never
visible
deformities
with
loss
and radiographic
osteoarthritis The radiograph the
583
KNEE
la
at 90#{176}.
Illustrative
OF THE
are demonstrated in Figure 3 was
early
bone
appearances deformities
in Figure 4a,
of both
bracing which
spaces
and
ability
held
12 years later, had progressed.
The photograph day
joint
to
. -
.
in Figure correct
the
and
in
the
manually
in
3).
and 1987,
No
5a was taken deformities
the
position
varus
on the same the
patient’s
actively
The radiograph was made with
corrected
surgical
radiographic
when
demonstrates
varus
her knees together. matches the photograph
Goodfellow
-
(Ahlb#{228}ck stage
as that
60-year-old patient was already in both knees. She had varus
medial
erosion
treatment was undertaken. Figure 4 shows the photographic
by
(Fig. Sb) the knees
(Gibson
and
1986).
Actual Radiographic
10
0
A
AB
B
BC
C
CD
D
Fig. 2 Fig. The site of deepest penetration from direct observation (Actual), lateral radiograph (Radiographic).
VOL.
73-B, No. 4, JULY
1991
of the erosions and estimated
into the tibial plateaux from the pre-operative
Anteroposterior bilateral medial
radiograph compartment
3
of both knees osteoarthritis.
of a 60-year-old
woman
with
S. H. WHITE,
584
P. F. LUDKOWSKI,
Photograph (a) and 12 years later.
..
Fig.
J. W. GOODFELLOW
radiograph
(b) ofthe
patient
shown
in Figure
3,
6a
THE
JOURNAL
OF BONE
AND
JOINT
SURGERY
ANTEROMEDIAL
Figure 6a shows the knees flexed
with no
longer
show
that when the patient was to 90#{176} the varus deformities
apparent.
that
OSTEOARTHRITIS
The
the
medial
backwards
out
of the
undamaged
posterior
lateral
radiographs
femoral parts
(Fig.
condyles
anterior
erosions
seated were
have and
6b), on
than
the
ation articular
the
of the plateaux.
He defined
narrowing
the
when
Very radiographic of the (1987)
few
We
We
have
Figure 7 shows the anterior cruciate ligament cartilage
of the
Medially,
there
the tibial
plateau.
lateral
compartment
was a deep The
All the features in the 46 knees
though
was
erosion
left knee
illustrated
whose
few ofthem
deformities
right knee at operation. The was intact and the articular
tibial
preserved.
of the anterior
was
part
of
we have
erosions
described,
or such severe
Previous
descriptions
of the morbid
anatomy
arthritis
of the
have
either
knee
depended
post-
mortem examinations or on the interpretation of radiographs. The post-mortem studies (Heine 1926; Keyes 1933; Bennett, Waine and Bauer 1942) were concerned with non-symptomatic degenerative changes which affect the population at large and have shed little light on the pathomechanics knee.
of
symptomatic
osteoarthritis
of
the
VOL.
73-B,
No. 4, JULY
1991
10 times
more
often
is
study
is situated varies with
et al little
possible
to
of
of the
tibial
morbid
osteoarthritis
shown that the osteoarthritis
together in flexion,
tibial erosion in (if the anterior
in the anterior the severity to
oblige the medial out of the anterior
onto the intact cartilage (Fig. 6b). 2) Therefore, each time collateral
length. This correctable release was
part of the
the posterior of an anterior offers
a logical
surface
erosion
group
femoral condyle depression and
posterior
the patient
tibial
flexes
is stretched
plateau
the knee,
out
the
to its proper
explains why the varus deformities remained by manual stress and why no soft-tissue required at operation in any of our cases. In
here, this mechanism maintained ligaments at their normal lengths
of demonstrable
for The
the term
deformity
‘anteromedial
(Figs
osteoarthritis
S
of entity and
and the suitability for unicompartall distinguish these cases from the
of varus
compartments
varus
the for at
the distinct clinicopathological clinical picture, the radiographic
anatomical findings, mental arthroplasty
other
of the
ligament
We propose the knee’ described.
osteoarthritic
of the joint
are
knees involved,
in which fixed
both
deformity
is commonly present and total replacement is the appropriate surgical treatment. We suggest that the orderly movement of the femur
mental
affected
it
but in no case did it extend of the plateau. The combination
compartment, to roll back
medial
being
Altman having
the
explains why the varus deformity is present in extension and not in flexion. The intact cruciate ligaments, acting with the preserved articular surfaces of the lateral
on
space
that
erosion and an intact cruciate mechanism explanation for the clinical signs: 1) The anterior position of the articular
In contrast, Ahlb#{228}ck’sradiological study (1968) was based on 370 knees with clinical osteoarthritis. In 85% of these joints he found that radiographic evidence of degeneration was limited to only one compartment, the joint
exclulateral
years.
in symptomatic
ligament is intact) plateau. Its extent
of osteoupon
and
were the
and the extent radiographs.
no previous
cruciate of the
least 12 years and 6).
DISCUSSION
many
They
joints
plane. Indeed, radiographs as
lesions
the case illustrated medial collateral
example.
over
to
arthritic
(1977).
lesions to involve
shown
knee, and have unicompartmental
medial
similar.
by this case were recorded plateaux
had such deep
as this
well
found
of tibial
of the
symptomatic
the site the lateral
of the medial
disease margin
patient’s right knee at operation. The anterior cruciate is well preserved as is the lateral tibiofemoral compartment. a deep erosion into the anterior part of the medial tibial In this flexed position the medial femoral condyle has rolled out of the deep depression on to the preserved cartilage of of the plateau.
have
accurately erosions from
anatomy
history
have been made on of the lesions of osteoarthritis
knee in the sagittal dismissed lateral
determine plateau
through
and Nilsson
followed
degener-
space
radiographic progressed
observations appearance
significance.
The same ligament There is plateau. backwards the back
natural of 94
that in 90% the medial and rarely
ofjoint
joint
by Hernborg
radiographs
compartment
grades
the
The
was reported
studied
five
of
subluxation.
found sively
Fig. 7
585
KNEE
lateral.
from
knee
rolled
lie
OF THE
the
tibia
in flexion
and
extension
protects
the
joint
with anteromedial osteoarthritis from developing fixed deformity. Therefore the factor which determines whether a particular knee deteriorates from unicompartto general
degeneration
may
be the
state
of its
S. H. WHITE,
586
anterior with
cruciate our
ligament.
findings
and
This those
hypothesis
P. F. LUDKOWSKI,
would
of Hernborg
and
J. W. GOODFELLOW
accord
Conclusions.
Nilsson
medial
(1977).
Furthermore, it would explain involvement of the lateral compartment unicompartmental 1979 ; Scott
Guhl
arthroplasty and
Santore
why
is rarely
seen
1981 ; Shurley
anterior part of erosion
secondary after medial (Marmor
which of the
et al 1982 ; Bae,
and Keane 1983; Inglis 1984; Knutson, Lindstrand Lidgren 1986; Cartier and Cheaib 1987; Deschamps Lapeyre 1987 ; Goodfellow et al 1988). Timely
and and
correction
of the varus
by prosthetic replacement of the eroded medial plateau before the cruciate ligament has stretched or ruptured should protect that structure lateral
and,
if our
compartment
conjecture from
is correct,
protect
the
degeneration.
of cartilage
may knee.
and bone
osteoarthritis,
cruciate ligament, the tibial plateau. can be determined
The authors photographed One or for personal or indirectly been or will institution, the authors
deformity
The pattern
unicompartmental
erosion
with
an
in
intact
constantly spares the posterior The site and extent of the from lateral radiographs
be diagnostic
of anteromedial
osteoarthritis
would like to thank Mr Paul Cooper who meticulously each specimen. more of the authors have received or will receive benefits or professional use from a commercial party related directly to the subject of this article. In addition benefits have also be directed to a research fund, foundation, educational or other non-profit institution with which one or more of is associated.
REFERENCES Ahlb#{228}ck S. Osteoarthrosis
of the
Acta Radiol[Diagn](Stockh) Altman
Bae
RD, progression
Fries
JF, Bloch in osteoarthritis.
KK, GuM JF, Keane single compartment four-year follow-up
DA
knee : a radiographic 1968 ; Suppl 277:7-72.
et al.
Radiographic
Arthritis
Rheum
SP. Unicompartmental disease : clinical study. C/in Orthop
Hernborg JS, Nilsson BE. The natural course of untreated ofthe knee. C/in Orthop 1977; 123:130-7.
investigation. assessment 30:1214-25.
1987;
of
knee arthroplasty for experience with an average 1983 ; 176:233-8.
Bennett
GA, Waine H, Bauer W. Changes in the kneejoint The Commonwealth Fund. OUP. New York. 1942.
Cartier
P, Cheaib S. Unicondylar knee arthroplasty follow-up evaluation. J Arthroplasty 1987; 2:157-62.
Goodfellow Oxford Surg[Br]
Heine
Stressradiography Joint Surg [Br] 1986;
JW, Kershaw CJ, Benson knee for unicompartmental 1988; 70-B :692-701.
J. Arthritis 521-663.
deformans.
Vfrchow’s
GS. Unicompartmental 3 to 9 years. J Bone
Jacobsen
Keyes
: 2-10
years
in degenerative 68-B :608-9.
of
arthritis
Path
Anat
1926;
Marmor L. Marmor modular Joint Surg [Am] 1979;
The Joint
260:
Stress
1984;
of the knee ; a follow-up 66-B :682-4.
radiographic
surfaces
RD, Santore for osteoarthritis A :536-44.
RF.
of the
knee
knee in unicompartmental 61-A :347-53.
Unicondylar of the knee.
of
patients
joint.
TH, O’Donoghue Unicompartmental five year follow-up.
THE
DH, Smith arthroplasty
C/in Orthop
JOURNAL
disease.
unicompartmental
J Bone Joint
of
measurement subjects and of application.
Acta
J Bone
Knutson K, Lindstrand A, Lidgren L. Survival of knee arthroplasties nation-wide multicentre investigation of 8000 cases. J Bone Surg[Br] 1986; 68-B :795-803.
Shurley Arch
K. Gonylaxometry.
EL. Erosions of the articular JointSurg 1933; 15:369-71.
Scott
MK D’A, O’Connor JJ. osteoarthritis. J Bone
arthroplasty
Joint Surg [Br]
passive stability in the knee joints of normal with ligament injuries : accuracy and range Orthop Scand [Suppl] 1981 ; 52(194): 1-263.
at various ages
Deschamps G, Lapeyre B. La rupture du ligament crois#{233}ant#{233}rieur : une cause d’#{234}checsouvent m#{233}connue des proth#{233}ses unicompartimentales du genou. Rev Chir Orthop 1987; 73:544-S 1. GibsonPH,GoodfellowJW. ofthe knee. JBone
Inglis
osteoarthritis
Surg
[Am]
:a
Joint J Bone
replacement 1981
;
63-
WD, Payne RE Jr, Grana WA. of the knee : a review of three1982; 164:236-40.
OF BONE
AND
JOINT
SURGERY