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CHAPTER 3THE COLIAPSING PES VALGO PLANUS FOOTKieran T. Maban,
M.5., D.P.M.
It can be considered bold to designate anyone asthe Father of
any particular aspect of foot andankle surgery. In the case of
flatfoot surgery, I feelconfident that there would be little
disagreementwith the statement that E. Dalton McGlamry, DPMis the
father of modern collapsing pes valgo planus(CP\?) surgery. More
important than his introduc-tion and popularization of cefiain
procedures hasbeen his consistent underlying philosophy regard-ing
the significance of the pathology. Much of themedical community has
looked upon CPVP surgeryas a cosmetic exercise, seeing little
functionalimportance. Early on, Dr. McGlamry recognized
thedestructive effects of equinus and CP\? along withthe
dysfunctional pain they inflict upon patients.lPerhaps now, with
the much greater awareness oftibialis posterior dysfunction (TPD)
in the adult, wecan see that CPVP is the precursor in a continuumof
failure of the stabilizing mechanisms of the footwith eventual
collapse.
PATHOLOGY
Equinus is a severely destructive force, either as aprimary
aspect of the deformity or as a secondaryresult of the CP\?. Vhen
the equinus is the pri-mary deforming force, compensation will
occur indistal joints such as the subtalar joint (SU) and
themidtarsal joints. How that compensation becomesexpressed in a
particular way is unclear. Thehypothesis of planal dominance is
helpful inexplaining some forms of compensation.'Z Thishypothesis
is based on two premises: 1. The axis ofmotion of the STJ can vary
widely, with extremesbeing a vefiical, horizonlal, or longitudinal
axis.The average STJ axis of 42 degrees up from thetransverse
plane, 15 degrees medial from the lon-gitudinal axis, may in fact
exist. More common is alarge amount of variation from the normal.2.
Compensation occurs in a plane perpendicularto the STJ axis. Thus a
STJ with a verticaT axis willcompensate in the transverse
plane.
There are difficulties with the planal domi-nance hypothesis.
First, it is clear that the motion of
the STJ is much more complex and dynamic thancan be explained
with planal dominance. Second,the axis of the STJ can only be
infered clinicallyand not measured. \7e infer the axis of
motionbased upon radiographic and clinical
findings.Radiographically, some joint relationships arethought to
be representative of certain axes. Forexample, a high cuboid
abduction angle combinedwith reduced talo-navicular articulation
are inter-preted to be representative of transverse
planecompensation from a vefiical axis. Clinically, onecan place
the STJ through its range of motion andappreciate, in some
patients, a tendency for motionto occur predominantly in one plane.
Nonetheless,the planal dominance hypothesis is a useful way
toinitially look at feet with CP\?.
Regardless of where the pathology occurs, theprimary element of
the pathology is instabiliry. Themedial column is most often
visible as the arca ofgreatest instabiliry. This is apparcnt in
static stanceas a lowered medial arch with heel valgus. In gait,the
medial column is seen to be initially stable withcollapse of the
arch during midstance and heel-off.Vithin the medial column, the
instability can occurat the talo-navicular joinl, the navicular
cuneiformjoint, or the first metatarsocuneiform joint. In
theseverely collapsed foot (usually an adult), instabil-i\r can
also occur at the ankle level, with stretchingand failure of the
deltold ligament. In the child,compensation seems to occur more
often at lhetalo-navicular joint. Medial column instabilicy wasonce
thought to be the primary deformity, and con-sequently was the
subject of numerous surgicalapproaches. These included soft tissue
re-balancingprocedures such as the Kidner or Young, andfusions such
as the Hoke and the Miller. TheLowman procedure combined elements
of both.3
Other approaches addressed the rearfooteither through the
orientation of the calcaneus(Silver, Kontsogiannis) or by blocking
of excesssubtalar motion (Gleich). Although lateral openingwedge
osteotomies seem logical for frontal planedominant CP\?, they have
diminished in popular-ity in recent years because of the
greater
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I8 CHAPTER 3
multi-planar changes effected by the Evansosteotomy. The
subtalar blocking approachremains popular with the use of a variety
ofarthroeresis devices.
ETIOLOGY
Donald R. Green, DPM, San Diego, California, haswritten and
lectured extensively on the biome-chanics of CP\?. He describes the
following asetiologies of CPVP:31. Forefoot varus2. Flexible
forefoot valgus3. Equinus4. Congenital talipes calcaneovalgus5.
Torsional abnormalities6. Muscle imbalance7. Ligamentous laxityB.
Neurotrophic feet9. Any factor (such as obesity) that produces
a
medial shift in weight bearing
EVAIUAIION
Evaluation of the CP\? foot is complex. It iscritical to identfi
the primary deforming force andthe primary site of compensation.
These componentsof evaluation include structural examination,
muscleinventory, biomechanical evaluation, radiographicanalysis,
Hubscher maneuvet clinical gait analysis,and quantitative gait
analysis.
Once the evaluation is complete, thephysician can consider the
benefits of surgicalversus conservative care. Indications for
surgicalrepair include pain unrelieved by conservative
care,progression of the deformity, instability, anddeformity. These
indications are modfied by thepatient's age, weight, degree of
pathology, functionaldemands, and response to conserwative
care.
PODIATRY INSTITUTE EVOLUTION
The Podiatry Institute approach has evolved con-siderably over
the past25 years. Initially, the Youngsuspension was used, based on
outstanding resultsreported in ihe European literature. The
responsewas good, particularly for creating some plan-tarflexion of
the first rzy, and stabilizing thenavicular cuneiform joint.
Advancement of tibialisposterior was then added to create some
transverse
plane stability. Later, additional tendon work wasrecommended,
including flexor digitorum longustransfer and peroneus brevis to
longusanastomosis. Tendo Achillis lengthening was addedearly on to
reduce the deforming forces created byequinus. Later still, the
Evans calcaneal osteotomywas added, after James V. Ganley DPM
hadintroduced it to the profession.'
TREATMENT
The Evans calcaneal osteotomy is an impressiveprocedure that
creates significant stability in therearfoot and midfoot without
arthrodesis.Originally described by Dillwyn Evans as a proce-dure
for treatment of over-corrected clubfoot andrigid flatfoot, the
procedure became useful as atreatment for CP\?.i The procedure
involves ananterior calcaneal osteotomy with lengthening ofthe
lateral column with a bone graft. This proce-dure has become the
dominant flatfoot procedureamong The Podiatry Institute
faculty.
Some critical elements for success of theEvans calcaneal
osteotomy include:1. Oblique incision, with careful attention to
avoid
the sural and intermediate dorsal cutaneousnerves.
2. Reflection of the EDB muscle be11y, being care-ful not to
disturb ligamentous attachments at thedorsal calcaneal cuboid
joint.
3. Through-and-through calcaneal osteotomy,about 1 cm proximal
to the calcaneal cuboidjoint. It should be angulated slightly
distal aswell.
4. Distraction of the osteotomy with a baby laminaspreader or
with pins and distractor to facilitateinsefiion of a truncated
wedge of aliogeneic orautogenous iliac crest (tri-cortical bone).
Thegraft is usually about 1 cm at its widest part andtapers to 7 mm
medially. An additional piece ofgraft can be applied to fill the
remainder of thedefect, although it is not mandatory.
5. Fixation of the graft is left to the judgement ofthe
surgeon.
6. Check the sagittal plane alignment, parlicularlylaterally.
Check the patient for equinus andcorrect as necessary.
7. Maintain the patient in a non-weight-bearingcast for B weeks
and allow protected weightbearing after that point, if radiographs
showgood consolidation.
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CHAPTER 3 I9
The sagittal plane correction in the lateralcolumn occurs with
plantarflexion of the cuboid onthe calcaneus. The mechanism for
this plantarflex-ion originates with the plantar calcaneal
cuboidligaments. As the lateral column is lengthened, theligaments
become stretched, and the cuboid andcalcaneus are drawn toward each
other, resulting inan increase in the calcaneal pitch. The
procedure iseffective in realigning ihe talo-navicular joint,
andreducing the cuboid abduction ang1e.6
Can the Evans be performed as an isolatedprocedure? Yes,
howevet, the author rarelyperforms it alone. Augmentation by medial
columnfusions and tendon balancing procedures will helpreduce the
forefoot varus and increase stabilitywithin the medial coiumn. The
author usuallyperforms the medial column tendon
suspension,consisting of the Young suspension of tibialis ante-rior
through the navicular, advancement of tibialisposterior, and
possibly tightening of the springligament. In sequence, the lateral
osteotomy isperformed first, and then the medial column ischecked
for position and stability with the laminaspreader holding the
osteotomy open. The medialcolumn is then opened if necessary, and
the sus-pension performed. The procedure is easier toperform before
the Evans bone graft has beeninserted, which reduces mobility of
the midfoot.Mosca6 uses a medial cuneiform osteotomy toaddress
medial column position and adductus ofthe forefoot (skewfoot).
SUMMARY
The CPVP foot is a surgical challenge. Recognitionof the
morbidity created by instability in the footand ankle is
increasing, but the general medicalcommunity is still generally
Lrnaware of the signifi-cance of CP\?. The Evans is a powerful
andimportant procedure for stabilizing the foot. Themedial column
suspension improves both positionand stability.
REFERENCES
1. Beck E, McGlamry ED: Modified Young tendosuspension for
theflatfoot. J Am Pod.id* Assoc 63:582-604. 1973.
2. Pressman MM: Biomechanics and surgical criteria for flexible
pesvalgtrs. J Am Pod Med Assoc 77:7-13, 1987.
3, Mahan KT: Pes planovalgus deformiry. In McGlamry ED, BanksAS,
Downey N4S, eds. Comprebensiue Textbook of Foctt Surgery.2nd ed.
Baltimore. Md: $f illiams and Wilkins; f992: 769'817.
4. Mahan KT, McGlamry ED: Evans calcaneal osteotomy for
flexiblepes valgus deformity. Clin Pod Mcd Surg 1:137-751",
L987.
5. Evans D: Calcaneo-vaigus deformity. / BoneJoint Surg
57(.8):270-278, 7975.
6. Mosca VS: Calcaneal lengthening for valgus deformity of
thehindfoot. J Bone Joint Sutg 77 (A) :500-572, 1995.