O R I G I N A L A R T I C L E

Mahmoud Ali Æ Ismail Said Æ Owen Barry

Clinical and radiographic evaluation of open wedge varus osteotomy
in Perthes disease

Received: 9 August 2005 / Accepted: 11 January 2006 / Published online: 9 September 2006
Ó Springer-Verlag 2006

Abstract Forty-two patients with Perthes disease treated
in Children’s Unit, Our lady’s of Lourdes Hospital be-
tween 1990 and 2002 were evaluated. Eighteen patients
(43%) with a severe form of Perthes disease who
underwent containment open lateral wedge varus oste-
otomy of the proximal femur were studied retrospec-
tively. Combined clinical and radiological review for
these patients yielded; seven LLD (39%), One broken
plate (5.5%), non-union (0%) and infection (0%). In our
study we achieved nil non-union result and the short-
ening effect and leg length discrepancy are lesser for the
open wedge osteotomy by performing a subperiosteal
osteotomy above the level of lesser trochanter.

Keywords Legg-Perhes disease Æ Varus osteotomy Æ
Femur

Oste´otomie de varisation a` coin externe dans la maladie
de Legg Perhes Calve´

Re´sume´ 42 patients pre´sentant la maladie de Perthes
traite´s dans l’unite´ des enfants de l’Hoˆpital de Notre
Dame de Lourdes entre 1990 et 2002 ont e´te´ e´value´s.
Dix-huit patients (43%) pre´sentant une forme se´ve`re de
la maladie de Perthes, qui ont e´te´ traite´s par oste´otomie
de varisation avec coin externe du fe´mur, ont e´te´ e´tu-
die´s re´trospectivement. La revue clinique et radiologi-
que combine´e de ces patients a mis en e´vidence; 7
diffe´rences de longueur des membres infe´rieurs (39%),
une fracture de plaque (5.5%), aucune pseudarthrose
(0%), aucune infection (0%) Dans notre se´rie, nous
avons e´vite´ la pseudarthrose et l’effet de raccourcisse-
ment de l’oste´otomie de varisation est minore´ si l’os-
te´otomie est re´alise´e en sous-pe´rioste´ en dessous du
petit trochanter.

Mots cle´s Maladie de Legge-Perthes-Calve´ Æ
Oste´otomie de varisation Æ Fe´mur

Materials and methods

Forty-two patients with Perthes disease treated in Chil-
dren’s Unit, Our lady’s of Lourdes Hospital betaween
1990 and 2002 were evaluated. Eighteen patients (43%)
with a severe form of Perthes disease who underwent
Containment open lateral wedge varus osteotomy of the
proximal femur were studied retrospectively.

The age of the patients ranged from 5 to 11 years

with a mean age of 8 years. There were 14 (78%) boys
and 4 (22%) girls. All patients were admitted to the
hospital 1 day before surgery and local and systemic
examinations of the children were performed.

The hip radiographs included anteroposterior (AP)

and frog lateral views (Figs.

1

,

2

).

The hips were classified according to principles pre-

sented by Herring: (18) hips were classified into Herring
lateral Pillar-C Group and the femoral neck shaft angle
was, on average, 30

°(26°–39°).

Eighteen patients underwent open lateral varus os-

teotomy of the proximal femur and internal Fixation by
Coventry scew and 100

°–110° angle plate (Fig.

3

).

Hip spica was applied for 6 weeks and children were

kept in hospital for 5 days and sitting up in and out of
bed was usually allowed. The implant was removed after
1.5–5 years with a mean age of 3.25 years after the
operation. The patients then followed up regularly for
clinical and radiological assessment. The final examina-
tion was performed, on average, 5 years (2–10 years)
after removal of metal, and union and infection rate and
leg length discrepancy was clinically measured.

Results

The varus of the femoral neck improves the coverage
of the femoral head. If pelvic obliquity occurs as a

M. Ali (

&) Æ I. Said Æ O. Barry

Orthopaedic Department, Children’s Unit,
Our Lady’s of Lourdes Hospital, Drogheda, Ireland
E-mail: [e-mail]
Tel.: [phone]

Eur J Orthop Surg Traumatol (2006) 16: 333–335
DOI 10.1007/s00590-006-0082-3

compensation for shortening the coverage is further in-
creased [

4

]. Femoral shortening together with any

compensatory pelvic obliquity leads to a change in
length of the abductors. In our study the result of pa-
tients treated with containment open lateral wedge varus
osteotomy of the proximal femur at a mean follow up
period of 3.25 years after removal of metal showed; 10
patients had excellent results (56%), there were no
infection (0%), no non union (0%; Fig.

4

,

5

), and no

vascular or anaesthetic complications occurred during
treatment. In 7 patients femoral shortening developed
(39%) of a mean average 1 cm (0.75–2 cm) and one
patient had broken plate (5.5%).

Discussion

Varus femoral osteotomy is a commonly employed
surgical method of effecting containment in the man-
agement of Perthes’ disease. This can be achieved by
performing either an opening lateral wedge or a closing
medial wedge osteotomy. Decision-making and treat-

ment regimens in the management of Perthes’ disease
remains controversial [

8

]. Axer, in 1965, was the first to

describe the use of a varus.

osteotomy for femoral head containment in Perthes’

disease [

1

]. Since then a large number of clinical series

have been reported, in which this form of surgical
management has been employed [

12

]. There is little in

the literature to indicate which technique for performing
a varus osteotomy produces the most favourable result
with respect to the geometry or function of the hip. In-
deed Moseley states that the effect of varus osteotomy
on abductor efficiency is unclear and that the beneficial
effect of increasing the lever arm may at least be partly
offset by the shortening and consequent weakening of
the abductor muscle [

10

].

Herring makes the important observations that no

investigator has reported statistically significant differ-
ences between treated groups and that most studies do

Fig. 2

Fig. 3

Fig. 4

Fig. 1

334

not have adequate controls to allow valid scientific
conclusions to be drawn. Selection biases may be
responsible for many of the reported differences [

6

].

Studies reported in the literature appear to show that the
success of osteotomy increases with the magnitude of the
angular displacement. Heilkkinen and Purenen looked
at the degree of varus angulation by comparing radio-
graphs taken preoperatively and at post-operative con-
solidation [

5

].

The varus angulation in their ‘39’ good hips was 28

°

(8.9 SD), in their nine ‘fair’ hips was 23

° (8.5 SD) and in

their ‘poor’ hips was 15

° (5.3 SD). The consequence of a

poor outcome may be that lateral extrusion occurs.
Karpinski et al. also demonstrated that the greater the
varus angulation the better the clinical result, with a
mean varus angulation of 32

° being optimum [

9

].

Excessive varus angulation of the proximal femur

should, however, be avoided because of the possibility of
over correction; most surgeons limit the reduction of
neck shaft angle to 110

° for this reason. Heikkinen and

Purenen suggest that the surgeon should aim for a post-
operative femoral neck shaft of 100

°–110°. A neck shaft

angle of 100

°, which would present a large varus angu-

lation angle in most children, is felt to be the safe limit
by Weinstein [

11

]. The femoral neck-shaft angle is rec-

ommended to be decreased to 100

°–110° to avoid

excessive shortening of the limb and overgrowth of the
greater trochanter [

5

,

16

,

17

].

Pelvic osteotomies in Legg-Calve-Perthes disease are

options when the hinge of abduction is fixed; the options
are a shelf acetabuloplasty, Chiari osteotomy, triple pelvic
osteotomy, or proximal femoral valgus extension osteot-
omy. Any of these procedures can be combined with a
proximal femoral varus osteotomy when severe deformity
of the femoral head cannot be contained by a pelvic or
proximal femoral varus osteotomy alone [

18

,

19

,

20

]. The

disadvantage of pelvic osteotomy is that the procedure is

performed on the normal side of the joint. Satisfactory
anatomical results range from 69 to 94% [

20

].

This study has sought overall the opening wedge

procedure is Preferable because it reduces femoral
shortening, a long terms consequence of varus osteoto-
my. If additional pelvic obliquity is required in the short
term it can be encouraged using a contralateral shoe
raise.

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Fig. 5

335