anteromedial osteoarthritis of the knee

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