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 quan
Trang 1After 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
The 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.11A shoe lift is not always well accepted as an alterna-tive.12Many 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.14In a review of 23 THAs complicated by peroneal and sciatic nerve palsy, Edwards et al15
noted an average lengthening of 2.7
cm (range, 1.9 to 3.7 cm) for
perone-al pperone-alsy 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
al7described a patient who, follow-ing a leg lengthenfollow-ing of 2.5 cm, re-ported pain without motor or
senso-ry deficit; the patient also had abnormal electromyography and nerve conduction velocities Pritchett16 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.
Trang 2lowing THAs in which limb
length-ening of 1.3 to 4.1 cm was
per-formed After evaluating factors that
influence nerve repair, Smith17
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 ngreat-erve, 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 al19 evaluated the
ef-fects of an artificial limb-length
dis-crepancy on gait economy and
low-er extremity muscle activity in oldlow-er
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 al20reported 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 Huson21reported 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 very 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 Rodriguez22noted 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 shortening, and an ad-duction contracture can increase perceived length.23Next, 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
Trang 3appropriate 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.3Patients 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
Trang 4plates, 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 al31
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
Trang 5level of neck resection varied by as
much as 7 mm
Woolson and Harris32 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 al33used 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 Atwater34conducted 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 trochantgreat-er may be used as an in-traoperative landmark for leg-length measurement.35However, 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 al7used 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 Scott37used 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 The 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.38,39One option
is to use two Steinmann pins, one in the pelvis and the other in the
great-er trochantgreat-er The distance between the two is measured before dislocat-ing the hip and durdislocat-ing 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 Bose41
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 trochantgreat-er 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
Trang 6the 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,42is
af-fected by many factors that make it
unreliable for leg-length
mea-surement.43-45However, 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 durmeasur-ing 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.40Functional 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,2624%
of patients required a shoe lift after THA A shoe lift also may alleviate some low back pain Friberg11
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.22Assurance 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,2214 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
Trang 7Surgical 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.18Simple
soft-tissue release may relieve
symp-toms associated with a minor degree
of inequality.22For 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
Pritchett16described 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 durtrack-ing 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 postoperapreopera-tive 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, William Lanzer, MD, Richard Rende, MD, and Kirk Kinds-fater, MD
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