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The value of preoperative planning for total
hip arthroplasty
S. Eggli, M. Pisan, M. E. M¨ ller
u
From the University of Bern, Switzerland

o analyse the value and accuracy of preoperative
planning for total hip replacement (THR) we
digitised electronically and compared the
hand-sketched preoperative plans with the pre- and
postoperative radiographs of 100 consecutive primary
THRs.The correct type of prosthesis was planned in 98%;
the agreement between planned and actually used
components was 92% on the femoral side and 90% on
the acetabular side. The mean (± SD) absolute
difference between the planned and actual position of
the centre of rotation of the hip was 2.5 ± 1.1 mm
vertically and 4.4 ± 2.1 mm horizontally. On average,
the inclination of the acetabularcomponent differed
by 7 ± 2° and anteversion by 9 ± 3° from the
preoperative plans. The mean postoperative leg-length
difference was 0.3 ± 0.1 cm clinically and 0.2 ± 0.1 cm
radiologically. More than 80% of intraoperative
difficulties were anticipated.
Preoperative planning is of significant value for the
successful performance of THR.

T

J Bone Joint Surg [Br] 1998;80-B:382-90.
Received 13March 1997; Accepted after revision 2 October 1997

Preoperative planning has always been an integral part of
1
2,3
total hip replacement (THR). Both Charnley and M¨ ller
u
emphasised the importance of preoperative radiographs in
deciding the type and size of prosthesis, in achieving the
correct position and orientation of the components, in
equalising leg length and in reducingintraoperative
1-5
complications.
Since 1968 we have stored all the preoperative plans of
THRs as well as the pre- and postoperative radiographs on

S. Eggli, MD
M. Pisan, MD
M. E. M¨ ller, MD
u
Department of Orthopaedic Surgery, University of Bern, Inselspital, Murtenstrasse 35, 3010 Bern, Switzerland.
Correspondence should be sent to Dr S. Eggli.
©1998 British Editorial Society of Boneand Joint Surgery
0301-620X/98/37764 $2.00
382

miniature, high-resolution photographs. A method of preoperative planning for THR was introduced by the senior
2
author (MEM) in 1975 and has remained remarkably
unchanged since then. We now present the technique and
analyse its accuracy and limitations.

Patients and Methods
We assessed the plans of 100 consecutive patients (100
hips)with idiopathic osteoarthritis who had had THR
between 1985 and 1988. The operations were carried out
through an anterolateral approach with the patient supine.
The senior author (MEM) was responsible for both the
plans and operations, records of which had been digitised
and stored, along with the radiographs.
There were 45 men and 55 women with a mean age at
surgery of 66 ± 8 years. Therewas no significant difference
between them (Student’s t-test, p = 0.192). In the women
the mean weight was 67 ± 5 kg and the mean height 166 ±
5 cm and in the men, 77 ± 7 kg and 175 ± 8 cm, respectively. Six patients had had previous intertrochanteric femoral osteotomies and one had internal fixation for a
subcapital fracture. In 33 patients the contralateral hip was
normal, in 31 there weresevere radiological signs of
arthritis and in 36 it had already been replaced.
The standard radiographs included a preoperative anteroposterior (AP) view of the pelvis with a lateral view of the
hip, and postoperative AP views of pelvis and acetabulum
and lateral views of the hip. The AP view of the pelvis is
taken with the patient supine and the centre of the X-ray
beam placed 2 cm above thepubic symphysis. The lateral
view is obtained with the patient in a 45° lateral position
with a flexed contralateral hip, and the acetabular view with
the patient supine and the centre of the X-ray beam placed
on the centre of rotation of the hip. To minimise variability
in magnification, the distance of the X-ray source to the
film cassette is standardised to 150 cm. All radiographs use
a...