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THE JOURNAL
OF ORTHOPAED~C
AND SPORTSPHYSICAL
THERAPY
Copyright O 1981 by The Orthopaedic and Sports Physical Therapy Sections of the
American Physical Therapy Association
Limb Length Discrepancies of the
Lower Extremity (The Short Leg
Syndrome)
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STEVEN I. SUBOTNICK,* DPM, MS
A survey of over 4,000 athletes and long distance runners, seen in my office over
the past 6 years, reveals almost 40% of some form of limb length discrepancy.
The limb length discrepancy is oftentimes associated with functional
abnormalities, such as overpronation of one foot in contradistinction to the other
or imbalances within the pelvis itself. Likewise, anatomical or true shortness may
be present or a combination of anatomical and functional discrepancies. There
appears to be a high correlation of injury on the short leg side and also associated
weakness with the shortening. Conversely, utilizing a heel lift for a functional
problem may cause contralateral symptoms. That being the case, it appears
appropriate for practitioners involved in treating athletes to be aware of the
various forms of limb length discrepancies that may exist, their significance, and
their appropriate treatment.
INTRODUCTION
I have been familiar with the importance of
limb length discrepancies in sports medicine for
the past several years. My first paper was written
prior to 1975. Dr. Karl Klein has also helped me
appreciate the significance of these discrepancies, and he published his earlier accounts in
1953. Since my earlier publications, clinical experience has allowed me to refine my original
thoughts on this subject, and this paper is a
representation of my current understanding.
Asymmetries of limb length which cause lateral
tipping of the pelvis and minor degrees of spinal
curvature have been reported frequently in the
literature.' 4 . 5. '-I2
Pearson's" progressive standing radiological
study of 830 school children from 8 to 1 3 years
of age indicated that 93% had some degree of
lateral asymmetry. Though compensation does
occur, the structural asymmetry does not improve materially. Klein5 demonstrated in 1953
that the greatest change in the development of
lateral asymmetry occurs between the elementary and junior high school years, but the pro' Professor, California College of Podiatric Medicine: President.
American Academy of Podiatric Sports Medicine: Fellow, American
College of Sports Medicine; Fellow, American College of Foot Surgeons.
cess continues into the senior high school ages.
Both Klein and Buckleys and Fahey3 noted the
relationship between foot pronation and lateral
asymmetry.
Anderson1 stated that asymmetries of 3/4-11/2
inches require foot correction or a heel lift. Limb
length discrepancies of less than 3/4 inch need
no correction, inasmuch as spontaneous compensation will take place. However, this author
has found that limb length discrepancies of I/'
inch or more, when associated with imbalance
symptoms, do need correction. Limb length discrepancies greater than % inch require a forefoot
lift of about one-half the thickness of the heel lift
to prevent equinus;' deviations of over 11/2 inch
may need a prosthetic device or shoe modifications; and major discrepancies may require surgery.
It has been my experience that at least 40%
of my athlete patients have some form of limb
length discrepancy. The limb length discrepancy
may be functional, anatomical, or a combination
of both. It may be associated with an injury or
the primary cause of the injury.
Limb length discrepancies of the lower extremity often cause disabling problems for runners.
Although major limb length discrepancies are
at a young age, minor discrepancies are frequently unnoticed until symp-
12
SUBOT'NICK
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toms ranging from low back pain to sciatica
develop.2,4. 5," A careful examination of the patient may reveal asymmetry of the pelvis secondary to an anatomical or functional shortening of
one limb. Pain in the low back, pelvis, or hip or
pain which radiates down the thigh (sciatica) can
be secondary to other causes, including primary
nerve disease or secondary nerve involvement.'
A third cause is low back strain which often
accompanies asymmetry of the lower extremities. When examination has eliminated other
causes of sciatica in the presence of limb length
discrepancies, heel lifts or orthoses can transform a runner with nagging, almost disabling
pain into a pain-free athlete.
TYPES OF LIMB LENGTH DISCREPANCIES
The basic measurement procedure for determining the symmetry or asymmetry of the posterior iliac spines is that recommended by Lowman," Redler,12and Klein and Buckley.' Lateral
pelvis imbalance of 'h inch or more is recorded
and determined by the thickness of the heel lift
necessary to achieve balance of the pelvis (posterior iliac spine) and spinal column with the
patient standing.
The patient should stand on a low table with
feet slightly apart, legs parallel, knees straight
ahead, and arms hanging naturally to the sides.
The investigator should palpate the posterior
superior iliac spine. Calibrated blocks of % 6 inch
should be added until the pelvic spines are level.
This measurement is basically for anatomical
limb length discrepancies. It fails to take into
account the functional limb length discrepancy
secondary to unilateral excessive pronation of a
foot or low back imbalances.
In the final analysis, what is important is that
the pelvis be level during neutral stance. One
must also differentiate between functional and
anatomical limb length discrepancies, and the
level of imbalance must be determined. Work
among the advocates of applied kinesiology has
shown that an unnecessary heel lift results in a
unilateral weakness. An uncorrected limb length
discrepancy likewise results in unilateral weakness. I prefer to examine my patients in several
attitudes and positions. The patients are examined sitting and standing. They are examined
lying down prone and supine. Measurements are
taken from the anterior superior iliac crest at the
medial malleolus of both legs and compared.
With the patient sitting, one observes if a sco-
JOSPT Vol. 3, No. 1
liosis is present. When the patient is standing,
the level of the pelvis is recorded, the amount of
lifts necessary for a level pelvis is noted, and the
presence or absence of scoliosis is noted. The
type of scoliosis and the level at which it occurs
is recorded. If the scoliosis disappears with sitting, then it is assumed to be functional. If the
scoliosis persists with sitting, it may be part of
the cause of the limb length discrepancy. It may,
likewise, be the result of a limb length discrepancy and be more advanced in nature. The presence or absence of paraspinal spasm is noted.
This is recorded in the chart and checked on the
next visit. Variations in the limb length between
the supine and prone position are noted and may
be accounted for by bipositional abnormalities of
the pelvis, sacroiliac joints, or low back. The
organic abnormalities could result in spasm
which would also be present with these positional variations.
I prefer to classify three types of limb length
discrepancies. The first is anatomical. It is actual
shortening of the limb, causing a tilt of the pelvis
and a secondary compensation of the spinal
column and resulting in scoliosis (Fig. 1A). The
second is functional. It is secondary to abnormal
hip positioning with the muscle spasm or abnormal foot positioning causing abnormal pelvis rotation (Fig. 1B). It may also be caused by malposition or spasm of the low back, sacroiliac
joints, or pelvis area. One must rule out organic
causes of low back strain contributing to pelvis
malrotation and scoliosis. The third is a combination of anatomical and functional discrepancies.
With structural limb length discrepancy, both
anterior and posterior portions of the pelvis will
usually be low on the side of the short leg.
Measurements of the patient supine and prone
will confirm the limb length discrepancy. There
may be a compensating curve of the spine convex to the short leg side. This usually disappears
during sitting. The shoulder blade (scapula) on
the long limb side will drop, and the arm on the
long leg side will appear longer than the arm on
the short leg side. If scoliosis is secondary to the
limb length discrepancy, it will disappear when
the patient is seated. If the limb length discrepancy is secondary to scoliosis or pelvic problems, it will persist while seated.
A flexible curvature of the spine may become
less flexible and less rigid with the passing of
time. The patient with the short leg syndrome
may compensate by externally rotating his foot
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JOSPT Summer 1981
LIMB LENGTH DISCREPANCIES
Fig. 1 . Anatomical short leg (A), functional short leg (B), and disappearance of functional short leg with orthotic control (C).
(Reprinted with permission from "Podiatric Sports Medicine, Steven I. Subotnick, DPM, MS, author, published by Futura
Publishing Co., Mt. Kisco, NY, 1975.)
"
and leg to provide for stability.' This complicates
the problem because an externally rotated foot
also has a valgus of the heel and associated
collapse of the arch.13 External rotation of the
leg on an internally rotated femur causes the
knee joint to suffer. Klein7 commented on the
relationship between externally rotated legs and
knee joint pathology among athletes.
If the patient has a functional limb length discrepancy at the foot level, the foot on the short
leg side will be externally rotated with the heel in
valgus and the medial arch collapsed. The patient with true limb length discrepancy, who compensates for lateral instability by externally rotating the foot, has the same appearance. When
the patient with functional discrepancy is examined, the rear pelvic spine may appear higher
than the front pelvic spine on the short leg side.
The internal rotation of the leg and the thigh,
which accompanies pronation or flattening of the
foot, causes the pelvis to rotate asymmetrically,
thus lowering the anterior pelvic spine and raising the posterior pelvic spine.
When there is functional imbalance in the low
back or pelvis, there oftentimes will be posterior
rotation of the pelvis on the short leg side. The
importance of functional imbalance in the pelvis
and low back has been largely ignored until
recently. For many years, many of my patients
would be measured and fitted for heel lifts and
then go to a chiropractor for adjustments of their
low back. They would return and no longer need
the heel lift or indeed need a lift on the opposite
side. It was noted that many of the scoliosis
deformities previously present were absent after
chiropractic manipulation. Reviewing the literature and speaking with orthopedists, chiropractors, and osteopaths has led to this conclusion:
there can be functional imbalances in the pelvis
and low back similar to the imbalances elsewhere in the body, and indeed, mobilization,
manipulation, and physical therapy may be indicated. One must rule out, at all times, any organic causes of low back pain or associated
radiating pain to the lower extremities.
It is easily observed that pronation of both feet
causes an accentuated lumbar lordosis. This
lordosis may result in low back pain. The use of
orthotics for mobile flat feet associated with excessive lordosis oftentimes eases the low back
pain. Orthotics also help with pelvic malrotation
which may result in low back pain. Orthotics may
not cure the problems but do indeed help them.
Sciatica likewise may be relieved with orthotic
14
SUBOTNICK
foot control when significant biomechanical abnormalities are present in the lower extremities.
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DIFFERENTIAL DIAGNOSIS OF LIMB
LENGTH DISCREPANCIES
To examine for structural limb length discrepancy, both heels should be placed in a perpendicular or neutral position with the arches of both
feet as close to normal as possible in normal gait
angle.I3 The posterior pelvic spines should be
palpated and differences in elevation noted. The
anterior pelvic spines should likewise be palpated and noted. The compensation in a true
limb length discrepancy is ascertained by building up the heel of the short leg side, using
different thicknesses of blocks until the iliac
spines are level. If the discrepancy is discovered
in childhood or early adulthood, this cpmpensating treatment may cause the curvature of the
spine to disappear and improve the angle of gait.
For a functional limb length discrepancy at the
level of the foot, both heels should be placed in
neutral position or close to vertical with the
arches of both feet normal. This will cause the
anterior and posterior iliac spines to become
level, the limb length discrepancy to disappear,
and the curvature of the spine to straighten. The
treatment of functional limb length discrepancy
within the foot is therefore neutral arch control.
This is accomplished by using orthotic devices
made over a cast of the patient's foot while the
foot is held in position of maximum function, the
neutral position.
Functional limb length discrepancies of the
back are noted by flexible scoliosis persistent in
neutral stance and in sitting. One may observe
that, even though the pelvis is level, the scoliosis
persists with heel lifts, and this is similar to the
scoliosis present during sitting. Scoliosis may be
present with or without associated paraspinal
spasm. This type of functional limb length discrepancy is best treated by physical medicine
techniques including mobilization, gentle manipulation, and exercises to strengthen all muscles
about the low back and pelvis. Additional physical therapy such as ultrasound may be indicated
if there is low back strain present. If any neurological abnormalities are found in the lower extremities, orthopedic or neurological consultation is necessary. Likewise, if history or physical
findings are consistent with an organic lesion,
orthopedic consultation should be sought. X-
JOSPT Vol. 3, No. 1
Rays and a neurological workup are indicated if
one considers a disc to be present with the
symptomatology.
Occasionally, combinations of anatomic and
functional limb length discrepancies will occur,
and it may be necessary to prepare'orthoses
with a heel lift on the short leg side.
At times, patient reactions are contrary to predictions. The patient's foot may function slightly
pigeon-toed on the short leg side, causing the
arch of the foot to be elevated with external
rotation of the leg as the foot is planted on the
ground. The elevation of the arch may also cause
some leveling of the pelvis.
SYMPTOMS ACCOMPANYING LIMB LENGTH
DISCREPANCIES
It has been my observation that most people
externally rotate the short legged side. This external rotation is accompanied by the majority of
the weight being medial to the foot. This causes
excessive pronation of the foot and likewise excessive medial strain on the entire lower extremity. There tends to be an increase therefore of
overuse injuries associated with the medial
structures of the lower extremity and likewise
the medial longitudinal arch. There is an increased incidence of chondromalacia patella in
athletes due to the increase of the functional Q
angle at the knee. This causes a tendency towards lateral overriding of the patella on the
lateral femoral condyle. This loss of proper tracking accounts for the majority of peripatellar pain
in athletes. A myriad of overuse injuries ranging
from greater trochanteric bursitis, to iliotibial
band strain, to flexor group shin splints or anterior tibial shin splints, and finally to medial ankle
synovitis, posterior tibial tendinitis, and medial
plantar fascitis must be included. The observed
weakness on the short side may also contribute
to the higher incidence of overuse injuries.
Symptoms accompanying limb length discrepancies include sciatica and generalized low back
~ a i n . ~Pain
, ' ~in the hip joint and pain along the
outside of one thigh and iliotibial band may accompany low back pain. Sciatica is a radiating
nerve pain beginning in the low back and running
down the inside of the thigh, sometimes to the
inside of the foot. The pain is accentuated when
the patient lies on his back and attempts a
straight leg raise. The pain is also more severe
when running uphill. Sciatica pain is often pres-
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JOSPT Summer 1981
LIMB LENGTH DISCREPANCIES
ent on the short leg side and may be associated
with low back strain or herniation of an intervertebral disc.I4 Primary and secondary nerve involvement must be ruled out. When sciatica is
secondary to limb length discrepancy, the response to a heel lift or an orthosis is dramatic.
Failure to obtain dramatic relief would indicate
further consultation with other medical specialists.
Low back pain or back strain may be associated with sacroiliac joint involvement, a nagging
pain over the buttocks. The patient would feel
more comfortable seated and resting on the noninvolved buttocks. This pain also presents a formidable list of possible causes which should be
investigated before the diagnosis of pain is
deemed secondary to limb length discrepancy.
SUMMARY
In summary, the importance of proper examination of the patient with limb length discrepancy
has been presented. The importance of determining the level of deformity is also discussed.
It is noted that neutral orthotic foot control will
take care of functional limb length discrepancies
with their origin in the feet and anatomical limb
length discrepancies are secondary to under- or
overdevelopment of the length of bone and are
corrected with appropriate heel lift. I find it most
useful to use full lift in the heel and one-half of
this amount under the ball of the foot with onefourth of the amount under the toes. Thus, a
patient with a 1-inch short leg would have 1-inch
buildup at the heel, M-inch buildup at the ball of
the foot, and %-inch buildup under the toes. This
wedge buildup appears to be more functional
than a straight I-inch lift for the entire sole of
the shoe. The lift may be placed in the midsole
and can be drilled to allow for weight reduction
in regards to running shoes or basketball shoes.
When a lift is utilized, a lateral flare on the shoe
or boot may be necessary inasmuch as the lift
may preclude increased lateral instability of the
foot and ankle.
Within the shoe or boot, lifts just short of '/2
inch may be used with success. For combinational limb length discrepancies occurring secondary to foot imbalance and anatomical discrepancy within the leg, orthotic foot control with
the lift built into the orthoses is most useful. An
example of this would be an orthot~cdevice, full
length, with 3/e-inch heel lift, 3/16-inch lift under
the metatarsal heads, and '/&inch lift under the
15
toes. The amount of varus tilt on this orthosis
would be reduced inasmuch as the heel lift tends
to supinate the calcaneus.
Minor limb length discrepancies which would
cause little difficulty in the nonathlete can cause
significant symptoms in the active athlete. This
is because of the rule of three. The rule of three
represents the fact that, in running, three times
the body weight goes through the support limb
whereas, in walking, about one times the body
weight is transmitted through the support limb.
Thus, biomechanical abnormalities of the lower
extremity tend to be three times more significant
in running than in walking. The rule of three is
illustrated by a patient with '/&inch limb length
discrepancy having no discomfort during walking yet chronic repetitive overuse injuries on the
short leg side during running. The '/4-inch limb
length discrepancy is as important as a 3/4-inch
limb length discrepancy in the nonathletic patient. Athletes require symmetrical body frames.
Symptoms secondary to structural or functional
limb length discrepancies frequently respond
dramatically to heel lifts and/or orthotic foot
control. Functional abnormalities secondary to
muscle imbalance or malrotation of bones in the
pelvis and low back must be dealt with appropriately by other professionals. The importance
of proper diagnosis cannot be overstressed. One
must always be mindful of organic causes of low
back strain which may range from inflammatory
autoimmune diseases, to discogenic disease, to
cancer. Appropriate referral and consultation is
necessary. One most utilize laboratory tests and
X-rays in establishing a differential diagnosis.
REFERENCES
1. Anderson WV: Modern Trends in Orthopedics, pp 1-22. New
York: Appleton-Century-Crofts, 1972
2. Beal MC: Review of short leg problem. J Am Osteopath Assoc
50:109-121, 1950
3. Fahey JF: Retarded leg syndrome (mimeo). Hollywood. CA. 1971
4. Green WT: Discrepancy in leg length of lower extremities. American Academy of Orthopaedic Surgeons Instructional Course
Lectures. VIII. Ann Arbor, MI: JW Edwards Co, 1951
5. Klein KK: Progression o t pelvic tilt in adolescent boys from
elementary through high school. Arch Phys Med Rehab1154:5759, 1953
6. Klein KK: Comparison of asymmetries in pelvis and legs of
elementary and junior high school boys (1964-68) (mlmeo).
Department of Physical Education for Men. University of Texas
at Austin, Austin, TX, 1968
7. Klein KK: Flexibility-strength
and balance in athletics. J Natl
Athletic Training Assoc 6:62-65, 1971
8. Klein KK. Buckley JC: Asymmetries of growth in pelvis and legs
of growing children: summation of three-year study (1 964-67).
Am Correct Ther J 22:53-55, 1968
9. Lovett RW: Lateral Curvature of Spine and Round Shoulders.
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16
SUBOTNICK
Chaps 4. 7. and 9. Philadelphia: Blakiston's Son and Co. 1912
10. Lowman CL, Colestock C. Cooper H: Corrective Physical Education for Groups. p 63. New York: AS Barnes 8 Co, Inc, 1937
11. Pearson WM: Progressive structural study of school children. J
Am Osteopath Assoc 51 : I 55-1 57, 1951
12. Redler I: Clinical significance of minor inequalities in leg length.
New Orleans Med Surg J 104:308-312. 1952
13. Sgarlato TE: A Compendium of Podiatric Biomechanics, pp 6065. San Francisco: CCPM, 1971
14. Wiltse I: The effect of the common anomalies of the lumbar spine
upon disc degeneration and low back pain. Orthop Clin North
Am 2:569-582, 1971
JOSPT Vol. 3, No. 1
BIBLIOGRAPHY
I.Subotnick SI: Podiatric Sports Medicine, pp 189-193. Mt. Kisco.
NY: Futura Publishing Co, 1975
2. Subotnick St: The Running Foot Doctor. Mountain View. CA:
World Publications. 1977
3. Subotnick SI: Cures for Common Running Injuries. Mountain
View, CA: World Publications. 1979
4. Subotnick SI: Case history of unilateral short leg with athletic
overuse injury. J Am Podiatry Assoc 70:255-256, 1980
5. Subotnick SI: Low back pain from functionally short leg. J Am
Podiatry Assoc 71 :42. 1981