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Leg-Length Discrepancy
After Total Hip Arthroplasty
Abstract
Leg-length discrepancy after total hip arthroplasty can pose a
substantial problem for the orthopaedic surgeon. Such discrepancy
has been associated with complications including nerve palsy, low
back pain, and abnormal gait. Careful preoperative measurement
and assessment, as well as preoperative and postoperative patient
education, are important factors in achieving an acceptable result.
However, after total hip arthroplasty, equal leg length should not
be guaranteed. Rather, the patient should be given a realistic
assessment of what can reasonably be expected.
T
he objectives of total hip arthro-
plasty (THA) include pain relief,
improved mobility and stability of
the hip, normal mechanics of the hip
joint, and, when possible, equality of
leg length. In general, obtaining pain
relief and improving stability take
precedence over restoring equal leg
length. However, leg lengthening
may be required to provide a stable
hip joint after reconstruction arthro-
plasty.
Data published by the Joint Com-
mission on Accreditation of Health-
care Organizations (JCAHO) provide
an account of the types of medical
errors that occur in hospitals in the
United States.

1
In his presidential
address to the American Academy of
Orthopaedic Surgeons, James Hern-
don, MD, remarked on the 19 major
events described by the JCAHO that
deserve watchfulness; 6 are relevant
to orthopaedic surgery.
2
Included
among these are patient falls and leg-
length issues; the latter account for
4.7% of medical errors.
Leg-length discrepancy after THA
has been associated with compli-
cations including sciatic, femoral,
and peroneal nerve palsy; low back
pain;
3-5
and abnormal gait.
6-10
Al-
though not quantified as a problem
in most series of hip arthroplasties,
low back pain in some cases may be
related to increased limb length of
the operated side.
11
A shoe lift is not
always well accepted as an alterna-

tive.
12
Many patients are annoyed by
leg- length discrepancy; patient edu-
cation is important in preventing
dissatisfaction. Patient dissatisfac-
tion with leg-length discrepancy af-
ter THA is the most common reason
for litigation against orthopaedic
surgeons.
12,13
Nerve injury is the most serious
complication associated with leg-
length inequality.
14
In a review of 23
THAs complicated by peroneal and
sciatic nerve palsy, Edwards et al
15
noted an average lengthening of 2.7
cm (range, 1.9 to 3.7 cm) for perone-
al palsy and 4.4 cm (range, 4.0 to 5.1
cm) for sciatic palsy. In a case report
describing acute sciatic and femoral
neuritis following THA, Mihalko et
al
7
described a patient who, follow-
ing a leg lengthening of 2.5 cm, re-
ported pain without motor or senso-

ry deficit; the patient also had
abnormal electromyography and
nerve conduction velocities.
Pritchett
16
reported on 19 patients
who had severe neurologic deficit
and persistent dysesthetic pain fol-
Charles R. Clark, MD
Herbert D. Huddleston, MD
Eugene P. Schoch III, MD
Bert J. Thomas, MD
Dr. Clark is the Dr. Michael Bonfiglio
Professor, Department of Orthopaedic
Surgery, University of Iowa Hospitals,
Iowa City, IA. Dr. Huddleston is in
private practice at Huddleston Hip and
Knee Institute, Tarzana, CA. Dr. Schoch
is in private practice, Austin, TX. Dr.
Thomas is Professor of Orthopaedic
Surgery, David Geffen School of
Medicine at the University of California,
Los Angeles, Los Angeles, CA.
Neither Dr. Huddleston nor the
department with which he is affiliated
has received anything of value from or
owns stock in a commercial company or
institution related directly or indirectly to
the subject of this article. Drs. Clark and
Thomas or the departments with which

they are affiliated have received research
or institutional support from DePuy. Dr.
Thomas or the department with which
he is affiliated has received nonincome
support (such as equipment or
services), commercially derived
honoraria, or other non-research–related
funding (such as paid travel) from
DePuy. Drs. Clark and Schoch or the
departments with which they are
affiliated serve as consultants to or are
employees of DePuy.
Reprint requests: Dr. Clark, University of
Iowa Hospitals, 200 Hawkins Drive,
01075 JPP, Iowa City, IA 52242.
J Am Acad Orthop Surg 2006;14:
38-45
Copyright 2006 by the American
Academy of Orthopaedic Surgeons.
38 Journal of the American Academy of Orthopaedic Surgeons
lowing THAs in which limb length-
ening of 1.3 to 4.1 cm was per-
formed. After evaluating factors that
influence nerve repair, Smith
17
con-
cluded that nerve lengthening of as
much as 15% to 20% of the resting
length was safe. However, for hip ar-
throplasty, the specific degree of

length that can be gained without
risking nerve palsy remains unde-
fined. Although surgeons generally
agree that progressively greater
lengthening is associated with great-
er risk to the nerve, no consensus ex-
ists regarding a safe threshold for
lengthening. Some sciatic nerve
problems that occur in the presence
of leg-length inequality are not
directly related to the leg lengthen-
ing.
Most patients with minor leg-
length discrepancy after THA have
few symptoms, and most patients
with moderate leg- length discrepan-
cy have readily manageable symp-
toms. However, a minority of pa-
tients, mostly those with marked
limb-length discrepancy, may have
substantial disability as a result of
pain or functional impairment.
18
Common symptoms include pain,
paresthesias, and instability of gait.
Gurney et al
19
evaluated the ef-
fects of an artificial limb-length dis-
crepancy on gait economy and low-

er extremity muscle activity in older
adults. They found that with 2 to 4
cm of limb-length discrepancy, there
was a significant (P < 0.0005) in-
crease in oxygen consumption. With
3 and 4 cm of limb-length discrepan-
cy, there was a significant (P = 0.001
and P < 0.005, respectively) increase
in heart rate and significant (P =
0.001 and P < 0.005, respectively)
quadriceps activity in the longer
limb. With a 4-cm limb-length dis-
crepancy, there was a significant (P
< 0.003) increase in plantar flexor ac-
tivity in the shorter limb. The au-
thors concluded that in older adults,
limb-length discrepancy of between
2 and 3 cm is the critical point with
regard to the effects on most physi-
ologic parameters. Elderly patients
with substantial pulmonary, cardiac,
or neuromuscular disease may have
difficulty walking with a limb-
length discrepancy as small as 2 cm.
Bhave et al
20
reported that a limb-
length discrepancy creates an asym-
metry in the ground reaction force
and that surgical lengthening of the

short limb to within 1 cm of the con-
tralateral limb reduced the asymme-
try to less than a significant level.
Vink and Huson
21
reported a notable
increase in the electromyographic
activity of the erector spinae mus-
cles only when the leg-length dis-
crepancy was ≥3 cm.
To prevent postoperative leg-
length discrepancy and its attendant
problems, it is important to under-
stand the various components of leg-
length assessment related to THA,
including preoperative planning, in-
traoperative measurement, and post-
operative management. With mini-
mally invasive techniques and
smaller incisions, the need for accu-
rate placement of implants is height-
ened. Computer-assisted surgery
may play a role in accurately deter-
mining such placement.
Preoperative Planning
Patient History
The patient’s perceived leg-length
discrepancy is a ver y important as-
pect of the preoperative history. It is
useful to ask patients specifically

whether their legs feel equal and
whether they use a shoe lift. A pa-
tient’s legs often are of unequal
length before surgery. Ranawat and
Rodriguez
22
noted a high prevalence
of asymptomatic leg-length inequal-
ity in the general population. Muscle
contracture frequently is a cause of
apparent discrepancy. A history of
scoliosis, poliomyelitis, develop-
mental dysplasia of the hip, degener-
ative disk disease of the lumbar or
thoracic spine, or lumbar surgery, in-
cluding spinal fusion, is important
and may have an effect on leg length
and the subsequent development of
symptoms.
Physical Examination
An abduction, adduction, or flex-
ion contracture should be assessed
and quantified because of the poten-
tial influence on perceived length. A
flexion contracture can lead to over-
estimating shor tening, and an ad-
duction contracture can increase
perceived length.
23
Next, the pelvis

should be leveled by placing a series
of blocks under the shorter limb. Fi-
nally, the true and apparent limb
lengths are measured.
3
The true limb length is deter-
mined by measuring the length of
the femur and implants. The appar-
ent limb length is determined by
adding the effect of soft-tissue con-
tractures and pelvic obliquity. Most
discrepancies are a combination of
true and apparent differences. Be-
cause functional limb length is the
result of a complex interaction of the
lengths of bones, implants, soft-
tissue contractures, and pelvic obliq-
uities, no single measure adequately
conveys all of this information.
The apparent leg length can be
measured from the umbilicus to the
medial malleolus. This technique
provides a simple measure of the
functional length; however, it does
not assess the effect of soft-tissue
contractures and pelvic obliquity.
This measurement also can be influ-
enced by the position of the limb and
the pelvis. The true leg length is
measured from the anterior superior

iliac spine to the medial malleolus.
This is arguably the most reliable
clinical measure of limb length;
however, the technique requires pre-
cise identification of landmarks,
which may be difficult, particularly
in obese individuals. True leg-length
measurement also is subject to vari-
ation because of changes in the posi-
tion of limbs and pelvis and because
of soft-tissue contractures.
24
The physical examination should
include an assessment of spinal de-
formity and iliac crest symmetry.
True leg-length differences may re-
sult in a compensatory scoliosis,
which may be resolved by placing an
Charles R. Clark, MD, et al
Volume 14, Number 1, January 2006 39
appropriate lift beneath the shorter
limb. Conversely, when contrac-
tures of the hip and knee cause a
fixed pelvic obliquity, placing a lift
beneath the shorter limb will not re-
solve the pelvic obliquity. Balancing
by using wooden blocks provides
easy assessment of functional leg-
length discrepancy in a reproducible
fashion; however, this method does

not adequately separate the effects of
soft-tissue contractures and fixed
pelvic obliquity.
Of particular concern is the pa-
tient who presents with a leg-length
discrepancy in which one leg is per-
ceived to be longer than the other al-
though the actual leg lengths are
equal. Common causes of such a per-
ceived “long leg” include scoliosis,
fixed pelvic tilt, and contralateral leg
deformity . Less commonly seen is an
abduction contracture in which the
true leg lengths are equal even
though the apparent leg length is
longer on the side of the contracture.
Patient Education and
Informed Consent
How a patient reacts to perceived
leg-length inequality is associated
with his or her discussion with the
surgeon, who can reassure the patient
that most inequalities have little im-
portance.
3
Patients retain little preop-
erative information about risks and
expectations, no matter how carefully
presented preoperatively; they re-
member more of the information pro-

vided about potential benefits.
25
During the preoperative discus-
sion, the surgeon should establish
the expectation that equal leg
lengths is not a guarantee after
surgery. Chronic shortening and tis-
sue scarring may make residual
shortening unavoidable at surgery.
Conversely, some individuals with
excessive laxity may require length-
ening to ensure adequate hip stabil-
ity. However, studies have reported
that, even after appropriate patient
education was provided and consent
given, approximately one half of pa-
tients with lengthened legs did not
recall that this possibility had been
communicated to them.
25,26
Ad-
ditionally, patients whose affected
side is longer preoperatively should
be warned that further lengthening
may occur as a result of surgery and
that deliberate shortening may not
be feasible.
Radiographic Assessment
Preoperative radiographs are help-
ful in assessing true leg-length dis-

crepancy; included should be an an-
teroposterior view of the pelvis with
both femurs internally rotated ap-
proximately 20° (Figure 1). External
rotation of the hip, which often oc-
curs in association with degenera-
tion, gives the false appearance of de-
creased femoral offset. This false
appearance can contribute to under-
estimating the offset and neck
length required to restore hip stabil-
ity and optimal biomechanics.
An appropriately rotated hip shows
the anterior and posterior aspects of
the greater trochanter to be in align-
ment and does not show the entire
lesser trochanter in profile. In patients
with unilateral disease, the anteropos-
terior pelvic view should have appro-
priate rotation on the contralateral
side. When an external rotation con-
tracture prevents appropriate internal
rotation in the supine position, plac-
ing the patient prone may correct the
radiographic appearance.
Determining radiographic leg
length can be difficult in a patient
undergoing revision THA, particu-
larly when significant metaphyseal
and/or diaphyseal bony deficiency

exists as a result of the previous ar-
throplasty. Attempts should be
made to identify radiographic land-
marks on the deficient side that can
be identified at surgery and used in-
traoperatively to help reapproximate
the appropriate leg length.
27,28
Preoperative Templating
Templating is useful for predict-
ing limb lengths. With acrylic tem-
Figure 1
As an estimate of leg-length discrepancy radiographically, a reference line is drawn
through the bottom of the obturator foramina. On each side, the distance from the
lesser trochanter landmark to the reference line is measured. The difference
between the two is the radiographic leg-length discrepancy. The tip of the greater
trochanter may be used as an alternative reference mark in conjunction with the
lines through the obturator foramina.
Leg-Length Discrepancy After Total Hip Arthroplasty
40 Journal of the American Academy of Orthopaedic Surgeons
plates, the surgeon is able to predict
the approximate change in limb
length by noting the relationship of
various implant landmarks, such as
the hip center and its relationship to
fixed bony landmarks (eg, the tear
drop, the lesser trochanter). The sur-
geon also can note how these land-
marks change with acetabular and
femoral implants of various size.

The templates are designed to fit
the internally rotated anteroposteri-
or view of the femur. Ideally the ip-
silateral side, when available, should
be templated first to determine the
potential correct sizes for both the
acetabular and femoral components.
It is important to remember that ra-
diographs typically are magnified up
to 20%.
Acetabular Templating
Preoperative acetabular templating
is performed with the following goals
in mind. First, the acetabular shell
should make bone contact at the sub-
chondral plate. The lateral opening
should approximate 40° ± 5°.
29,30
Fi-
nally, in most cases, the tear drop
should coincide with the infe-
romedial corner of the acetabular
component. Placing the acetabular
template in this position establishes
the new center of rotation of the THA
(Figure 2). Placement of the acetabu-
lar component as close as possible to
the templated position is important
because doing so defines the hip cen-
ter and directly influences leg length.

Femoral Templating
When templating the femoral
side of the acetabular socket, there
are three main goals: optimally size
the femoral component, maintain
offset, and optimize limb lengths.
With appropriately aligned, internal-
ly rotated femoral views, the sur-
geon should be able to determine
whether an adequate offset can be
achieved with the implants being
considered. One method to create a
larger offset is to make a lower neck
cut and use a longer neck. Another
strategy to obtain a larger offset is
the use of lateralized femoral com-
ponents. The advantage of using lat-
eralized femoral components is that
offset can more readily be restored
without lengthening the limb.
Trochanteric advancement can
improve soft-tissue tension without
increasing leg length. Disadvantages
to using this method, however, in-
clude the risk of trochanteric bursi-
tis, nonunion, increased operating
time, and the potential need for
tension-band wire removal.
The use of templates is the first
step in obtaining acceptable clinical

results with regard to leg length.
31-33
However, such use should be com-
bined with a reliable intraoperative
method to obtain optimal length.
Intraoperative Leg-
Length Measurement
Application of Preoperative
Templating Intraoperatively
Because determining limb length
intraoperatively relies on identifying
anatomic landmarks, patient posi-
tioning is important to ensure prop-
er orientation of these landmarks.
Before draping, with the patient in
the position that will be evaluated
intraoperatively, the baseline limb
length is assessed with respect to the
contralateral limb. It is also helpful
to check that landmarks on the con-
tralateral extremity can be palpat-
ed intraoperatively through the
drapes.
The accuracy of preoperative fem-
oral templating relates in part to the
location of landmarks from which to
measure the level of the femoral
neck resection during surgery. Al-
though the lesser trochanter is com-
monly used, its sloping superior sur-

face blends with the inferior femoral
neck and therefore may not always
provide a definitive landmark, either
on radiographs or intraoperatively. In
a series of 100 consecutive hip sur-
geries in which the authors mea-
sured from the lesser trochanter and
used digitized radiographs and a spe-
cial software program, Eggli et al
31
found that the actual to the planned
Figure 2
Using the anteroposterior radiograph, the template is positioned 35° to 45° to the
inter–tear drop or interischial line, so that the inferomedial aspect of the cup abuts
the teardrop and the superior-lateral cup is not excessively uncovered.
Charles R. Clark, MD, et al
Volume 14, Number 1, January 2006 41
level of neck resection varied by as
much as 7 mm.
Woolson and Harris
32
measured
from the top of the femoral head to
the level of the neck resection, a
practical method when the femoral
head is not deformed and the pre-
operative leg-length difference is
minimal. Woolson et al
33
used this

technique and radiographically de-
termined postoperative leg-length
discrepancy for a consecutive series
of 351 patients (408 hips) who under-
went bilateral or unilateral primary
THA. Ninety-seven percent of the
patients had a postoperative leg-
length discrepancy of <1 cm. The av-
erage discrepancy for these patients
was 1 mm.
Knight and Atwater
34
conducted a
prospective study of 110 consecutive
primary THAs in which surgeons re-
corded the preoperative plan that was
used to determine implant size; im-
plant sizing was correctly predicted
from the plan for 62% of acetabular
cups (69 of 110) and for 78% of ce-
mented stems (43 of 55); how-
ever, correct sizing was predicted
from the plan in only 42% of
cementless stems (23 of 55).
Surgeons stray from the template
plan for cases in which implants of
different size or offset are used, the
femoral neck resection is not made
where intended preoperatively, the
neck cut is modified to provide bet-

ter implant fit, or a tight press-fit
femoral component fails to fully
seat. A further variable is the diffi-
culty of predicting the actual superi-
or and medial extent of acetabular
reaming.
Intraoperative Radiographs
An intraoperative radiograph can
be taken with trial components in
place and radiographic landmarks
measured, as in revision surgery
templating. When possible, both
hips should be clearly visible on the
film. However, metallic patient po-
sitioners that can obscure landmarks
may need to be removed during film
exposure, making intraoperative
magnification hard to assess and ac-
curate positioning difficult.
Intraoperative
Measurements
As noted, proper patient position-
ing and identification of baseline
landmarks are important. The great-
er trochanter may be used as an in-
traoperative landmark for leg-length
measurement.
35
However, the center
of the femoral head does not always

coincide with the superior tip of the
greater trochanter.
36
Several intraoperative methods to
measure for implants use one or
more reference pins driven into the
pelvis. Measurements are made from
the pin to a mark on the greater tro-
chanter. The leg should be placed in
the same position during each mea-
surement.
Mihalko et al
7
used a method in
which a large unicortical fragment
screw is placed above the superior
rim of the acetabulum. The screw-
driver is placed in the hex-headed
screw; as the baseline limb length,
the distance is measured from the
shaft of the screwdriver to a mark
made with the cautery at the vastus
tubercle on the lateral aspect of the
greater trochanter. After the implan-
tation of the prosthetic trial compo-
nents, a check is made to ensure the
appropriate limb length.
McGee and Scott
37
used a method

in which a Steinmann pin is driven
into the pelvis 1.5 to 2 cm superior to
the acetabulum and bent into a U. A
mark is made at the point where the
free end of the U contacts the greater
trochanter. T he pin is swiveled out of
the operative field and returned dur-
ing measurements, with each mea-
surement obtained with the legs in a
reproducible position. Restoring the
mark to the tip of the pin restores the
preoperative length, and suitable ad-
justments are then made from that
reference point. The tip of the pin is
used to reference hip offset.
Because a standard Steinmann
pin may be too short in obese pa-
tients, other measuring pins have
been recommended.
38,39
One option
is to use two Steinmann pins, one in
the pelvis and the other in the great-
er trochanter. The distance between
the two is measured before dislocat-
ing the hip and during trial measure-
ments. However, a trochanteric pin,
which is removed and replaced in its
track during measurements, may be
unreliable.

38
A variety of measuring calipers
has been described in which one end
articulates with a pin, pins, or spikes
anchored into the pelvis, while a sty-
lus at the other end references off a
mark on the greater trochanter.
40
Another device combines a spirit
level with the two-pin method to
eliminate variations in the abduc-
tion/adduction position of the leg
during measurements. Bose
41
report-
ed its use in 117 operations; by using
the device, the leg was lengthened
>12 mm in 5% of hips, compared
with 31% lengthening without the
device.
Other devices also can measure
offset with the use of a vertical cal-
iper. In the lateral decubitus posi-
tion, the horizontal distance be-
tween the tip of the stylus and the
marked point on the femur repre-
sents the change in leg length,
whereas the vertical distance be-
tween the tip of the stylus and the
lateral surface of the greater tro-

chanter represents the change in hip
offset. A removable caliper decreas-
es the risk of bending or dislodging
the pin. The pin should not be used
to retract the wound edge or the ab-
ductor muscles because doing so
may cause it to bend or dislodge
from soft bone. Finally, a separate
skin stab incision may be required.
The accuracy of all of the meth-
ods that measure from pins anchored
in the pelvis to a point on the great-
er trochanter may be affected by the
inherent variability of the leg posi-
tion when measurements are made.
Because bending a pin or dislodging
it from osteoporotic bone will com-
promise measurements, an intraop-
erative radiograph of the pelvis with
Leg-Length Discrepancy After Total Hip Arthroplasty
42 Journal of the American Academy of Orthopaedic Surgeons
the trial components in place still
may be necessary. Variation caused
by changes in leg position can be
lessened by creating a rigid cradle for
the operated leg.
39
Performed following reduction of
trial implants, the so-called “shuck”
test, described by Charnley,

42
is af-
fected by many factors that make it
unreliable for leg-length mea-
surement.
43-45
However, the test can
provide some sense of hip stability,
and it may influence the surgeon’s
decision on the desired final leg
length.
The use of a stable pelvic refer-
ence, combined with a method for
accurately positioning the leg during
measurements, provides the surgeon
with a practical method for measur-
ing leg length during hip arthroplas-
ty. Such a method helps the surgeon
select implants that provide optimal
fit and allows him or her to stray
from the preoperative plan, confi-
dently using femoral neck and sock-
et modularity to adjust the final leg
length.
Postoperative
Assessment and
Treatment Options
Perception of leg-length inequality is
common after the surgical proce-
dure.

40
Functional but transient ine-
quality was found to occur in 14 of
100 patients in one study. Persistent
functional limb-length inequality
(FLLI) is far less common and is
found most often in patients who are
short of stature or who already have
some degeneration of the spine.
22
Perceived Inequality of Leg
Lengths
Pain is the most obvious and fre-
quent symptom associated with a
perceived postoperative FLLI: low
back pain may be associated with an
overlengthened leg; impaired abduc-
tor function and possibly hip disloca-
tion may occur with shortening.
3
Of-
ten a patient’s legs were of unequal
length before the surgery, and it is
important to document this baseline
measurement preoperatively. FLLI af-
ter THA also may result from a pre-
existing degenerative process in the
lumbar spine that is producing scoli-
osis and pelvic obliquity.
22

Postoperative Assessment
A careful physical examination
that includes a neurovascular assess-
ment is important. Determination
of FLLI should be delayed until
rehabilitation/recovery has pla-
teaued, typically 3 to 6 months after
surgery.
Preoperative and postoperative
clinical measurement of the legs is
important; radiographic measure-
ments may provide further helpful
information. Orthoroentgenography,
commonly known as a “scano-
gram,” may provide a clear measure-
ment of true leg-length inequality.
46
In some cases, a computed tomogra-
phy scanogram may give the most
accurate assessment of leg lengths,
particularly in patients with a flex-
ion deformity of the knee. In addi-
tion, computed tomography delivers
only 20% of the radiation needed for
orthoroentgenography.
46
Perhaps most useful is simple but
thorough questioning and observa-
tion of the patient. How does the leg
feel when standing? How does the

leg feel when using the walker? Is
there pain in the lower back, iliac
crest, groin, or abductors? Is the gait
awkward? Do these problems seem
attributable, at least in part, to leg-
length discrepancy?
Treatment
Nonsurgical management of a
perceived or true leg-length inequal-
ity can take several forms. The most
expedient initial treatment is the in-
sertion of a shoe lift for the leg that
seems to be shorter; thickness of up
to three-eighths of an inch can be in-
serted without altering the shoe it-
self. In a study by Edeen et al,
26
24%
of patients required a shoe lift after
THA. A shoe lift also may alleviate
some low back pain. Friberg
11
de-
scribed a series of more than one
thousand cases in which simply pro-
viding an adequate shoe lift to cor-
rect leg-length inequality resulted in
permanent and mostly complete al-
leviation of symptoms.
However, one should be some-

what cautious regarding the early
use of a shoe lift because such use
may prevent soft-tissue contractures
or pelvic obliquity from “relaxing”
and perhaps resolving. Therefore,
when a lift is used, the surgeon may
choose to compensate only for the
actual or perceived length discrepan-
cy. Similarly, in most cases, it is de-
sirable to delay the use of a lift for
approximately 6 months postopera-
tively to determine whether the per-
ceived leg-length discrepancy will
resolve.
Equally important is the perspec-
tive assumed by the physical thera-
pist. A positive attitude toward the
outcome of therapy by the therapist
may make a difference in the pa-
tient’s accommodation of a different
sensation. Such a sensation may be
felt even when the legs are anatom-
ically the same length after surgery.
Most patients experience gradual
(over approximately 6 months) im-
provement with therapy that
stretches soft tissue and relieves pel-
vic obliquity.
22
Assurance from the

therapist that the leg will work well
with adequate stretching and manip-
ulation may affect eventual out-
come.
As with any change in the body,
the “tincture of time” may be all
that is necessary for satisfactory
functioning. For example, of the 100
patients reviewed by Ranawat and
Rodriguez,
22
14 had pelvic obliquity
and FLLI 1 month after surgery, but
by 6 months postoperatively, all of
these symptoms had subsided with
the use of physical therapy. Like-
wise, in a study by Abraham and Di-
mon,
3
perceived postoperative ine-
quality was most common in
patients with preoperative discrep-
ancies in leg length and usually re-
solved with time.
Charles R. Clark, MD, et al
Volume 14, Number 1, January 2006 43
Surgical options are available
when nonsurgical management fails
to produce the desired effects. Possi-
ble indications for surgical manage-

ment include severe hip or back
pain, hip instability, paresthesias,
and foot drop that the surgeon deter-
mines may be improved by reducing
the leg-length discrepancy.
18
Simple
soft-tissue release may relieve symp-
toms associated with a minor degree
of inequality.
22
For the small subset
of patients who have a leg that is too
short, a modular head can be
changed to increase leg length; how-
ever, the increase in length usually is
small. For shortening >2 cm, revi-
sion to a femoral component with a
longer base neck length (eg, a calcar
replacement prosthesis) may be con-
sidered.
More commonly, patients find the
leg length to be too long after THA.
Femoral shortening can be accom-
plished by exchanging a modular head
for a shorter one, although this can
lead to instability and may only mar-
ginally decrease the length. Treat-
ment by shortening may improve
motor impairment after lengthening.

Pritchett
16
described motor improve-
ment in 7 of 11 patients who had re-
vision shortening of from 0.5 to 3.6
cm. He noted that when painful neu-
rologic symptoms accompany leg
lengthening after THA, revision hip
surgery may be helpful although pa-
tients should be informed that the
rate of success is far from uniform.
When shortening is done, it may be
necessary either to exchange the fem-
oral component for one with an in-
creased offset, use a larger femoral
head, or perform a trochanteric os-
teotomy to achieve stability. A fur-
ther option is use of a constrained ac-
etabular liner . If the hip is stable and
functions well but the leg is still too
long, shortening can be accomplished
by a distal femoral osteotomy. All sur-
gical options should be undertaken
with caution because of the unpre-
dictability of symptom improvement
and the risk of creating new problems
(eg, hip instability).
Finally, when hip disease exists in
the contralateral hip and contralater-
al arthroplasty is contemplated, it

may be reasonable to use a shoe lift
and other nonsurgical management
until the time of the second opera-
tion, when the leg lengths can be ap-
proximated.
In the future, it is likely that ad-
vances in technology will lead to
greater precision and accuracy in the
management of leg length.
47
With
the advent of navigation/image-
guided surgery technologies, correc-
tion of limb-length inequality may
be dramatically enhanced. Registra-
tion of three-dimensional bony anat-
omy, coupled with real-time track-
ing during surgery, may allow the
surgeon to accurately balance limb
length to within 1 or 2 mm of the
contralateral side, based on preoper-
ative measurement and planning.
Current image-guided systems use
computed tomography scans, fluoro-
scopic imaging, or point matching/
surface registration with optical
scanners and morphing technology
to provide anatomic referencing for
the femur and pelvis at the time of
surgery. The relative position of

these bony structures can then be
tracked in real time as implant ad-
justments (eg, cup position and
placement, femoral implant posi-
tion, offset, femoral head diameter,
neck length) are made that affect
limb length. Finally, the surgeon can
evaluate limb length, range of mo-
tion, hip stability, and possible im-
pingement of components or ana-
tomic structures before closure to
ensure optimal clinical outcome.
Summary
Careful preoperative measurement
and assessment, as well as preopera-
tive and postoperative education of
the patient, are important factors in
gaining an acceptable result with re-
gard to leg lengths after THA. Equal-
izing perceived or actual leg length
should not be guaranteed. The pa-
tient should be given a realistic ex-
pectation of what may be likely after
surgery; the preoperative and postop-
erative visits during which this in-
formation is conveyed can be quite
important to the eventual outcome.
Ideally, the surgeon’s communica-
tion with the physical therapist
should go beyond written orders; a

surgeon’s attitude and positive ex-
pectations may well be adopted by
the therapist and passed on to the pa-
tient. Only in rare circumstances in
which nonsurgical measures—in-
cluding education, recovery time,
physical therapy, and shoe lifts—fail
to bring satisfactory resolution
should surgical intervention be con-
sidered for leg-length inequality.
Acknowledgment
The authors wish to acknowledge
that they and the other members of
the Western Consensus Panel of
Depuy/Johnson & Johnson were in-
volved in the development of this
consensus statement: Peter Buchert,
MD, William Bugbee, MD, James
Caillouette, MD, Charles Creasman,
MD, Robert Gorab, MD, Wayne Hill,
Lin Jones, MD, W illiam Lanzer, MD,
Richard Rende, MD, and Kirk Kinds-
fater, MD.
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