Ann R Coll Surg Engl 1997; 79: 58-68
Pathological anatomy and dynamic effect of
the displaced plantar plate and the
importance of the integrity of the plantar
plate-deep transverse metatarsal ligament
G D Stainsby FRCS
Consultant Orthopaedic Surgeon
Royal Victoria Infirmary and Freeman Hospital Trusts*, and Nuffield Hospital, Newcastle upon Tyne
Key words: Foot deformities; Hallux valgus; Toes; Metatarsophalangeal joint
Normal and deformed forefeet have been investigated
by cadaver anatomical dissections and experiments,
by radiographs, CT and MRI scanning, and by clinical
Evidence is presented to show that the skeleton of
the foot rests on and is controlled by a multi-
segmental ligamentous and fascial tie-bar system.
Transversely across the plantar aspect ofthe forefoot,
the plantar plates and the deep transverse metatarsal
ligaments form a strong ligamentous structure which
prevents undue splaying of the forefoot. Longitudin-
ally, the five digital processes ofthe deeper layer ofthe
plantar fascia are inserted into the plantar plates and
control the longitudinal arch of the foot.
It is suggested that many forefoot deformities result
from the failure of parts of the tie-bar system and the
dynamic effect of displacement of the plantar plates.
Understanding this allows a more logical approach to
The multisegmental tie-bar system and the
The transverse tie-bar
A sagittal section through the metatarsophalangeaI joint
of a lesser toe of a normal cadaver foot shows that below
the metatarsal head the capsule is thickened to form the
'plantar plate'. It is firmly attached to the base of the
proximal phalanx. Below and anterior to this is the
thickened subcutaneous tissue adapted for weight-bearing
which is the plantar pad (Fig. la).
The plantar plates of the metatarsophalangeal joints
and the intervening deep transverse metatarsal ligaments
form a continuous band of strong ligamentous tissue
across the forefoot (Fig. lb), and on transverse section each
plantar plate is seen to be anchored to its metatarsal head
by the collateral ligaments (Fig. lc).
*Retired from National Health Service appointnents on 1 July
Based on a Hunterian Lecture given at the Meeting ofthe British
Orthopaedic Association in Nottingham on 16 September 1994
Correspondence to: Mr G D Stainsby, 9 Meadow Court, Darras
Hall, Ponteland, Newcastle upon Tyne NE20 9RB
Radiological studies on normal living feet demonstrated
forefoot. Measurements were made from the medial
border of the first metatarsal to the outer border of the
the width across
Displaced plantar plate
Figure 1. (a) Sagittal section through lesserMTP joint of a
normal foot showing the thickened plantar capsule (plate)
beneath the metatarsal head. (b) The transverse tie-bar
(altemate plantar plates and deep transverse metatarsal
ligaments). (c) Transverse section through normal fore-
foot at metatarsal head level showing the plantar plates
and the collateral ligaments.
fifth, the average increase in 20 female feet was 3 mm, and
5 mm in the feet of 10 males.
studies withdivision of the deep
Lateral traction was applied to the metatarsals of three
dissected cadaver forefeet before and after division of the
deep transverse metatarsal ligaments. It was found that
after division of the ligaments the first metatarsal moved
more medially, and the fourth and fifth metatarsals more
laterally away from the second and third metatarsals.
It was seen that the plantar plates and the deep
transverse metatarsal ligaments form a segmental 'tie-
bar' across the forefoot which controls the splay between
neighbouring metatarsals as well as between the first and
The longitudinal tie-bar mechanism
Hicks (1,2) described the mechanisms supporting the
longitudinal arch ofthe foot; the 'beam' mechanism which
operates when the ends of the arch are not fixed, and the
remembers his explanation of the windlass mechanism
controlling the plantar fascia, and that the longitudinal
arch of the foot rises as a result of dorsiflexion of the big
toe (Fig. 3a), but Hicks also pointed out that this
mechanism is present in all the toes, and that the
windlass works in reverse when the flat foot is submitted
to a weight-bearing strain (Fig. 3b).
Dissections of cadaver feet have confirmed the findings of
Poirier (3) and Bojsen-M0ller and Flagstad (4) that in the
distal part of the sole of the foot, at about the level of the
necks of the metatarsals, the plantar fascia divides into
superficial and deep layers. The deeper layer of the
plantar fascia is thick and strong and divides into five
processes. Each process goes towards its corresponding
toe, and close to the metatarsal head divides into two
strong slips, between which the flexor tendons emerge to
come to lie on the plantar aspect of the plantar plate.
These two slips pass dorsally around the flexor tendons
and are inserted into the medial and lateral sides of the
plantar plates of the metatarsophalangeal joints (and the
sesamoids under the first metatarsal head). Fibres from
these plantar fascial slips were found to sweep medially
and laterally into the proximal edges and substance of the
intervening deep transverse metatarsal ligaments, and in
doing this fibres from neighbouring medial and lateral
slips interdigitated (Fig. 4).
The effect of tightening the deeper part of the plantar
fascia in a normal cadaveric foot with intact metatarso-
phalangeal joints was studied. When the plantar fascia was
relaxed the toes could be dorsiflexed at the metatarso-
phalangeal joints. When weight-bearing was simulated
with pressure under the metatarsal heads, the longitudinal
arch flattened, the plantar fascia tightened, the toes flexed
down, and it was then found that the proximal phalanges
of the toes could not be dorsiflexed from this position.
The reversed windlass mechanism can be observed in the
normal living foot when standing with the toes over the
edge of a footstool or table. When weight-bearing on the
metatarsal heads the toes flex down and the proximal
G D Stainsby
Figure 2. The 'beam' and the 'truss (or tie-bar)' mechanisms as described by Hicks.
phalanges resist being pushed up into dorsiflexion. The
interphalangeal joints remain mobile, indicating that the
long flexor and extensor tendons are not responsible, and
that the flexion of the proximal phalanges is due to the
tight plantar fascia tethering the plantar plates.
This has been called the 'footstool edge weight-bearing
test'. Normally all the toes (or to be more correct the
proximal phalanges) come down to the same level and are
in slight plantarflexion (Fig. 3c,d). This test can be used to
assess the integrity and performance of the windlass
mechanism of the plantar fascial process to each toe.
The windlass effect is greatest in the big toe and is seen
in gradually lessening degrees in the second, third, and
fourth rays and is almost absent in the fifth. This can be
related to the size of the metatarsal head, which is the
pulley, and the length of the lever, which is the toe (or its
The transverse tie-bar (plantar plates and deep transverse
metatarsal ligaments) controls the splay of the forefoot.
Figure 3. (a) Dorsiflexion of the big toe and the windlass effect of the plantar fascia as
described by Hicks. (b) The 'reversed' windlass mechanism (with weight-bearing the
longitudinal arch flattens, the foot lengthens, the plantar fascia tightens, the proximal
phalanx becomes plantarflexed and the mechanism comes to a stop when the proximal
phalanx presses against the ground). (c) and (d) The 'footstool edge weight-bearing test'.
Displaced plantar plate
|J ... .....
plna fasc*ials prcse
Xtie|-bar. _ _|
Figure 5. Diagrammatic illustration ofthe multisegmental
fascial and ligamentous tie-bar system of the foot.
The five longitudinal processes of the deeper layer of the
plantar fascia form a longitudinal tie-bar system. They are
inserted into the whole of the transverse tie-bar and they
are very strong.
The longitudinal tie-bar system (the deeper layer ofthe
plantar fascia) controls the longitudinal arch of the foot
when the normal foot is weight-bearing. Both tie-bars are
centred on the plantar plates and are activated by weight-
bearing pressure on the metatarsal heads. If two or more
metatarsal heads are submitted to upward pressure from
weight-bearing they will tend to splay apart and the
corresponding metatarsal rays will flatten. For example,
when weight-bearing on only the medial three metatarsal
heads the medial part of the tie-bar system will be active
and tighten. The proximal phalanges of the medial three
toes are then held down in flexion but the lateral two toes
The foot skeleton therefore rests on and is controlled by
a multisegmental ligamentous transverse and longitudinal
tie-bar system. This system is capable of automatically
responding to theweight-bearing surface and adjusting the
posture ofthe foot skeleton, and of altering the alignment
of the mid-foot and hind-foot when the forefoot only is
weight-bearing and the toes are dorsiflexed during 'heel
elevation'. Differingtensions inthemedial and lateral parts
ofthe longitudinal system can be adjusted by movement of
the os calcis as occurs with inversion and eversion of the
heel (Fig. 5).
Deformities of the foot and defects in the
multisegmental tie-bar system
Further studies have shown that defects in the tie-bar
system can explain why common forefoot deformities
In the normal
sesamoid bones articulate with grooves on either side of
a longitudinal ridge (the crista) on the plantar aspect of
the metatarsal head. A V-shaped pulley is therefore
formed (Fig. 6a).
Anatomical and CAT scan studies have been carried
out on eight cadaver feet with hallux valgus and these
confirm Haines and McDougall's (5) findings that as
hallux valgus develops the crista is gradually eroded away
by the medial sesamoid (Fig. 6b), and that the metatarsal
head then drifts medial to the sesamoid bones as the
medial capsule becomes stretched. In severe hallux valgus
the lateral sesamoid groove of the metatarsal head comes
to articulate with the medial sesamoid and the lateral
sesamoid migrates to the lateral side of the metatarsal
G D Stainsby
Figure 6. Transverse CT scans of
forefeet. (a) The normal first MTP
straddled over the crista. (b) Moder-
ate hallux valgus with erosion of the
crista by the medial sesamoid. (c)
Medial displacement of the first MT
head and medial sesamoid articulat-
ing with the lateral groove under the
Displaced plantar plate
When the big toe is normal and unconstrained, and the
foot is weight-bearing, the equal tension in the two
plantar fascial slips to the sesamoids, straddled over the
prominence of the crista, will keep the toe straight (Fig.
7a). However, if the toe is pushed laterally into valgus by
the tightness or shape of a shoe, the plantar fascia will
metatarsophalangeal joint. The medial sesamoid must
then impinge with increased pressure against the medial
side of the crista of the metatarsal head. If the crista
becomes eroded the stability of the sesamoid articulation
and its ability to resist lateral displacement is lost (Fig.
7b,c). Once the first metatarsal head moves medially, the
bow-string effect of the plantar fascia, which is tight
throughout the weight-bearing period, will be established
and will inevitably cause progressive valgus angulation of
the big toe. It is therefore suggested that the wearing of
narrow and pointed-toed shoes is a potent cause ofhallux
Patients with hallux valgus have been assessed by the
'footstool edge weight-bearing test' and it was found that
the ability of the plantar fascia to keep the proximal
phalanx of the big toe plantarflexed became progressively
less as the valgus deformity increased. Indeed, when the
deformity was severe the test failed to produce any
response and the toe remained dorsiflexed and rotated.
This can be explained by the realisation that, as the valgus
deformity develops, the plantar plate and sesamoid bones
fall off their pulley
(the metatarsal head),
effectiveness of the windlass mechanism of the plantar
fascia of the big toe gets less and less as the metatarsal
head moves medially. The resulting slackening of the
longitudinal fascial tie-bar on the medial side of the foot
explains the loss ofheight of the medial longitudinal arch
ofthe foot which is usually seen in feet with hallux valgus.
Hicks showed that the excursion of the sesamoids
around the first metatarsal head of the normal foot when
the big toe is dorsiflexed is only about 1 cm (2). Our
studies have confirmed this. Therefore, only a slight
defect in its plantar fascial windlass mechanism will have a
profound weakening effect.
across the lateralside of the
Figure 7. (a) Normal alignment of the plantar fascial
process to the big toe. (b) With the big toe pushed into
valgus the medial sesamoid impinges against the crista. (c)
The bow-string effect ofthe plantar fascia when the crista
When the big toe windlass mechanism fails, then
control and support of the longitudinal arch of the foot
will depend increasingly on the tie-bar mechanism of the
particularly the second and third.
Digitus minimus varus
Haines and McDougall (5) suggested that this deformity
can be regarded as a 'mirror-image' to hallux valgus.
Cadaver dissections, and CAT and MRI scans have
confirmed this and demonstrated that the lateral capsule
of the fifth metatarsophalangeal joint stretches allowing
the metatarsal head to drift laterally away from the plantar
plate and the proximal phalanx. The plantar fascial
process to the little toe then becomes a deforming force
as it bow-strings across the medial side of the metatarso-
Cadaver dissections and MRI scan studies have shown
that as clawing ofa lesser toe develops, and the metatarso-
phalangeal joint becomes dorsiflexed when the foot is
weight-bearing, the plantar plate and the plantar pad are
pulled distally and follow the proximal phalanx around
the metatarsal head (Fig. 8a). When the claw deformity
dislocated, the plantar plate is then displaced on to the
dorsal aspect of the metatarsal head. The head is then
invariably prominent on the plantar aspect of the forefoot
with very little tissue cover (Fig. 8b).
When a lesser toe is clawed the proximal phalanx is no
longer held down into flexion by its plantar fascial process
when the foot is weight-bearing and so the flexor and
extensor tendons can cause the typical deformity. For this
to happen the windlass mechanism of the plantar fascia to
the toe must be defective.
The middle of the plantar plate of lesser toes is thinner
where it is grooved for the flexor tendons. Dissections of
cadaver feet with clawed toes have shown that as the
metatarsophalangeal joint of a lesser toe becomes dorsally
subluxed the proximal part of the plantar plate stretches
and even ruptures in the grooved area. This confirms the
previous reports of Fitton and Swinburne (6) and
Johnston et al. (7). This defect allows the distal part of
the plantar plate to move to the dorsal aspect of the
metatarsal head with the base ofthe proximal phalanx and
the plantar fascial slips to slide dorsally around the sides
of the metatarsal head (Fig. 9a,b). They are therefore no
longer around the circumference of the metatarsal head
and become ineffective. Indeed, when the slips have
moved dorsal to the axis of rotation of the metatarso-
phalangeal joints, they will depress the metatarsal head as
It has been shown experimentally that when the plantar
plate is displaced dorsally it is tethered by the deep
transverse metatarsal ligaments and this causes depression
of the metatarsal head by a 'plunger' effect (Fig. 9a). It is
'plunger' mechanism and the
Hammer toe deformity is seen frequently in second toes
which are longer than the big toe. Typically, when the
foot is weight-bearing the metatarsophalangeal joint is
dorsiflexed, the proximal interphalangeal joint flexed and
weight-bearing (and when the footstool edge weight-
bearing test is performed) the longitudinal tie-bar to that
toe must be defective, and the central part of the plantar
plate stretched, allowing the plantar fascial slips to slide
offthe greatest diameter ofthe metatarsal head. A possible
explanation is the wearing of shoes that are too short so
causing the long toe to 'buckle'.
Figure 8. Sagittal sections through lesser MTP joints of
cadaver feet. (a) Moderate clawing with distal movement
of the plantar plate and pad. (b) Severe clawing. Plantar
plate now on dorsal aspect ofthe MT head, and very little
tissue remains under its plantar surface as the plantar pad
has also moved distally and dorsally.
malalignment of the plantar fascial slips are the causes of
metatarsal head depression seen in the severely clawed
lesser toe. The 'plunger' effect has been clearly observed
many times at operation, and corrected by replacing the
plantar plate under the metatarsal head.
It is therefore concluded that defects in the ligamentous
tie-bar systems of the foot allow deformities of the
forefoot to develop. Failure of the medial capsular
ligaments of the first metatarsophalangeal joint (after
erosion of the crista of the metatarsal head) results in
hallux valgus; stretching of the lateral capsular ligaments
of the fifth metatarsophalangeal joint is present in digitus
Clawing ofthe lesser toes is often seen to develop in feet
with hallux valgus. It is suggested that in feet with a
significant deformity of the big toe the powerful windlass
mechanism of its plantar fascial process is defective and
that the longitudinal tie-bar function ofthe plantar fascia,
controlling the medial arch ofthe foot (particularly for the
'push-off' phase of the walking cycle), will fall upon the
fascial processes to the lateral four toes. They are not as
mechanical advantage is not as good as they are more
closely placed to the axis ofmovement ofthe subtalar joint
complex, and their windlass mechanisms are not as
powerful, as the diameters of the metatarsal heads and
the proximal phalanges of the lesser toes are smaller than
those ofthe big toe. Perhaps, therefore, it is not surprising
that the plantar plates of the central lesser toes then give
way where they are stretched over the metatarsal heads.
as the fascial
to the big
Figure 9. (a) When a lesser toe is severely clawed the plantar plate becomes dorsally
displaced; tethered by the deep transverse metatarsal ligaments it causes MT head
depression by the 'plunger' effect. (b) The plantar fascial slips slide around the MT
head as the central part of the plate stretches. If they now tighten the MT head will be
G D Stainsby
Displaced plantar plate
Stretching of the central part of the plantar plate of a
lesser toe allows displacement of the slips of the plantar
fascia from offthe greatest circumference ofthe metatarsal
head, making the windlass mechanism ofthe plantar fascia
ineffective. Dorsiflexion deformity can then develop at the
metatarsophalangeal joint when the foot
bearing, and this can progress to dorsal dislocation of
the joint and dorsal displacement ofthe plantar plate. The
effect of the displaced plantar plate, and
malalignment of the plantar fascial slips, then cause
depression of the metatarsal head and metatarsalgia.
The multisegmental tie-bar ligamentous
system of the foot and the principles of
surgical treatment of forefoot deformities
When it is realised that the skeleton ofthe foot is to a great
extent controlled by a ligamentous tie-bar system, and
that defects in this system result in deformities ofthe fore-
foot and toes, it is surely logical to try to repair these
defects when the deformities are corrected surgically.
Many surgical procedures have been described for the
correction of hallux valgus-soft
osteotomies of the first metatarsal and the proximal
phalanx of the big
metatarsophalangeal joint of the excision and replace-
ment type. The results of these operations have usually
been assessed with regard to patient satisfaction, cosmetic
appearance and alignment of the big
reduction in the angle between the first and second
metatarsals has been measured on radiographs. The
postoperative position of the first metatarsal head relative
to the sesamoid bones has rarely been recorded, and the
function ofthe big toe with regard to the restoration of its
plantar fascial windlass mechanism does not appear to
have been assessed.
Our studies indicate that one of the most important
functions of the big toe during the weight-bearing phase
of walking is to activate the windlass mechanism of the
most medial process of the plantar fascia. It is the
strongest part of the longitudinal tie-bar system which
elevates the arch of the foot, and realigns the bones of the
foot skeleton so that the direct weight-bearing thrust from
the ankle is transferred down the medial side of the foot
when the heel is elevated. To restore this function, if it is
possible, must surely be one of the main aims of surgery
for hallux valgus. The stretched medial capsule ofthe first
metatarsophalangeal joint also requires tightening so that
the medial splay of the first metatarsal is controlled.
It is suggested that if, when surgery for hallux valgus is
carried out, the first metatarsophalangeal joint can be
toe, and arthroplasties of the
toe, and the
preserved, the medial capsule should be tightened and the
first metatarsal head replaced over the sesamoid bones.
The effectiveness of the windlass mechanism of the
plantar fascia will only be fully restored if the first
metatarsal head is correctly positioned above the sesamoid
bones. Should an osteotomy of the first metatarsal be
required (if there is restricted movement at, or malalign-
ment of, the first tarsometatarsal joint) then shortening of
the first metatarsal needs to be avoided as this will weaken
the windlass mechanism. If a lateral release procedure is
carried out to the first metatarsophalangeal joint, then
division of the deep transverse metatarsal ligament
between the first and second metatarsals should be
avoided, and the integrity of the lateral slip of the
plantar fascia and its lateral sesamoid attachment needs
to be preserved as otherwise a varus deformity of the big
toe may result from the unbalanced pull of the medial
plantar fascial slip.
When the first metatarsophalangeal joint is degenerate
and cannot be retained, then, if an excisional arthroplasty
is carried out, it is suggested that the medial capsule
should still be tightened to restore the integrity of the
transverse tie-bar, and so prevent splaying of the first
Digitus minimus varus
It has been demonstrated that in this deformity the lateral
capsule of the fifth metatarsophalangeal joint becomes
stretched. Itwouldseem logical,therefore,thatwhenthis is
corrected the surgical procedure should include tightening
of the lateral capsule so that the fifth metatarsal head is
moved medially and replaced over its plantar plate.
For the early deformity, where the metatarsophalangeal
joint is still stable and the capsular ligaments intact,
procedures such as fusion ofthe proximal interphalangeal
joint and flexor-extensor transfer have produced satisfac-
tory results. Both these procedures aid plantarflexion
control of the proximal phalanx and may be sufficient to
prevent progression of the dorsiflexion at the metatarso-
Treatment of the severe claw deformity is notoriously
difficult. Metatarsalgia has often persisted after excision of
the base of the proximal phalanx, and the previously
reported good results from various types of metatarsal
osteotomy (8-10) have recently been questioned.
The investigations and studies reported here show
that in severe claw deformity of a lesser toe the plantar
plate becomes displaced onto the dorsal aspect of the
metatarsal head. This results
metatarsal head owing to the 'plunger effect'. To correct
this, andthe metatarsalgia,
necessary to replace the plantar plate to its normal
position beneath the metatarsal head and to preserve the
length of the metatarsal. Shortening of the metatarsal
will cause slackening of the plantar fascia and loss of
in depression of the
G D Stainsby
Figure 10. Diagrammatic illustration of the 'modified
Keller's procedure' for severely clawed lesser toes. (a) V-
shaped incision to avoid longitudinal skin contracture. (b)
Extensor tendon divided at the level of the MT neck and
reflected distally. (c) Proximal phalanx sectioned through
the neck and the shaft and base removed preserving the
plantar plate. (d) and (e) Plantar plate replaced beneath
the MT head using a periosteal elevator which is taken
under the MT neck. (t) Stabilise toe in correct alignment
with an intramedullary wire, suture the extensor tendon
to the flexor tendons without tension, and excise any
excess extensor tendon. Close wound with small sutures.
the windlass mechanism, and the weight-bearing struc-
tures (the plantar plates and pads) are left distal to
the metatarsal head. Osteotomy of the distal shaft of
the metatarsal without replacement of the plantar plate
can result in uncontrolled displacement of the head
fragment by the 'plunger mechanism'.
Since 1976, the author has corrected severe clawing of
lesser toes by a procedure which preserves the metatarsal
head and replaces the plantar plate. The principal steps of
the procedure are shown in Fig 10.
The results of this operation in 74 feet with a single
severely clawed toe were reviewed independently in 1990
(11). The average length of follow-up was 3.5 years. In
85% the results were considered to be excellent or good
with satisfactory cosmetic appearance, and relief of pain
Provided the metatarsophalangeal joint is not subluxed or
dislocated, fusion of the proximal interphalangeal joint
usually corrects the deformity and the proximal phalanx
comes down against the ground when the foot is weight-
bearing. The added power ofthe short flexor tendon, now
acting to plantarflex the proximal phalanx, assists the
weakened windlass mechanism of the plantar fascia and
helps to prevent dorsiflexion at the metatarsophalangeal
joint when the foot is weight-bearing.
The rheumatoid forefoot
Severe deformity of the toes can occur in patients with
rheumatoid arthritis. Gross hallux valgus and marked
clawing of the lesser toes with prominence of the
metatarsal heads in the sole ofthe foot is commonly seen.
In 1912, HofEman (12) recommended excision of the
metatarsal heads for the severely deformed rheumatoid
forefoot. A number of modifications to this procedure
have been described (13-15). So, for over 80 years,
excision arthroplasty with removal ofthe metatarsal heads
has been the usual procedure for this condition. Although
some good results have been reported it is accepted that
the foot is inevitably shortened, that there can be
subsequent problems with exostoses developing on the
stumps of the metatarsals, that plantar callosities recur
(16), and that postoperatively many patients need surgical
When it is accepted that the metatarsal heads control
the multisegmental tie-bar system of the foot, it follows
that excision of the metatarsal heads must completely
destroy the ligamentous tie-bar support to the foot.
Since 1976 the author has carried out a forefoot
reconstruction procedure preserving the metatarsal heads
(Fig. 11). In this operation the valgus deformity ofthe big
toe is corrected by a Keller's procedure with division of
both long and short extensor tendons and tightening of
the medial capsule. The severe clawing of lesser toes is
corrected by the procedure previously described for the
treatment of the
single severely clawed
metatarsal heads are preserved and an attempt is made
to reconstruct the ligamentous tie-bar system as far as is
possible. The plantar plates are replaced to their correct
position and the transverse tie-bar tightened. The plantar
pad also returns to its weight-bearing position beneath the
metatarsal heads and any plantar skin callosities move
proximally and subsequently separate spontaneously.
The results of this forefoot reconstruction on 42 feet
were reviewed independently (11). The mean follow-up
was 5 years (range 2 years to 11 years 7 months). At
review, 34 feet (81%) were considered excellent and 5
(12%) good (example shown at Fig. 12). Many patients
were able to dispense with surgical shoes, the length ofthe
feet was preserved, 39 (93%) had no pain, only three had
plantar callosities and 14 patients were able to walk
comfortably on the forefoot alone.
The foot skeleton is supported and controlled by a multi-
segmental ligamentous and fascial tie-bar system centred
on the plantar plates of the metatarsophalangeal joints.
The integrity and correct positioning of the compo-
Displaced plantar plate
Figure 11. (a) Incisions for forefoot reconstruction. (b) Diagrammatic illustration of
correction ofdisplaced plantar plates and repair ofthe medial and lateral ends ofthe
nents of the multisegmental longitudinal and transverse
tie-bars are necessary for the normal function of the foot.
The longitudinal tie-bar system (the deeper layer ofthe
plantar fascia) is controlled by the windlass mechanism as
described by John Hicks.
The function of the longitudinal tie-bar system can be
assessed by the 'footstool edge weight-bearing test'.
malalignment of the plantar plates allow and cause
deformities of the forefoot and toes to develop.
When deformities ofthe forefoot and toes are corrected
surgically, an attempt should be made to reconstruct the
tie-bar system, and so restore normal foot anatomy and
function as far as is possible.
When there is severe clawing of a lesser toe the
'plunger' effect of the dorsally displaced plantar plate
causes depression of the metatarsal head. When treated
surgically it is important to replace the dorsally displaced
plantar plate to its correct position under the metatarsal
When the severely deformed rheumatoid forefoot is
treated surgically, it is recommended that the metatarsal
heads be preserved as they are an essential part of the
weight-bearing structure of the forefoot and they control
the tie-bar systems.
Figure 12. (a) and (b) Severely deformed rheumatoid
forefoot before surgery. (c) and (d) One year after forefoot
The anatomical studies wouldnot have been possible without the
help and guidance of Professor Simon Miller, and I am
particularly grateful to Mrs Christine Harkness who kindly
carried out the cadaver dissections in the School of Anatomy of
the University of Newcastle upon Tyne.
The co-operation, generosity and enthusiasm ofthe staffofthe
X-ray Department and the Alliance Medical MRI Unit at the
Nuffield Hospital, Newcastle upon Tyne, and the Radiology
Department and CT Unit at the Royal Victoria Infirmary, are
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G D Stainsby
The author also wishes to thank Mr John Bulmer, Mr Peter
Briggs, Professor Garth Johnson and, in particular, Professor
Leslie Klenerman, for their help, advice, and encouragement.
1 Hicks JH. The foot as a support. Acta Anat 1955; 25: 34-45.
2 Hicks JH. The mechanics of the foot. II. The plantar
aponeurosis and the arch. J Anat 1954; 88: 25-30.
3 Poirier P. Traite d'Anatomie Humaine. Vol 2, Paris: L
Battaille et Cie, 1892: 296.
4 Bojsen-Moller F, Flagstad KE. Plantar aponeurosis and
internal architecture ofthe ball ofthe foot. J Anat 1976; 121:
S Haines RW, McDougall A. The anatomy of hallux valgus. J
Bonejoint Surg 1954; 36B: 272-93.
6 Fitton JM, Swinburne L. Degenerative lesions of the
accessory plantar ligaments. Int Orthop 1981; 4: 295-8.
7 Johnston RB, Smith J, Daniels T. The plantar plate of the
lesser toes: an anatomical study in human cadavers. Foot
Ankle Int 1994; 15: 276-82.
8 Giannestras NJ. Plantar keratosis, treatment by metatarsal
shortening. J Bonejoint Surg 1966; 48A: 72-6.
9 Helal B, Greiss M. Telescoping osteotomy for pressure
metatarsalgia. J Bone joint Surg 1984; 66B: 213-17.
10 Mann RA, Coughlin MJ. Keratotic disorders of the plantar
skin. In: Mann RA, Coughlin MJ, eds. Surgery of the Foot
and Ankle, 6th Edition. St Louis: CV Mosby 1993: 427.
11 Stainsby GD, Briggs PB. Modified Keller's procedure for the
lateral four toes. J Bone joint Surg 1990; 72B: 530.
12 Hoffman P. An operation for severe grades of contracted or
clawed toes. Am J Orthop Surg 1912; 9: 441-8.
13 Fowler AW. A method of forefoot reconstruction. J Bone
joint Surg 1959; 41B: 507-13.
14 Clayton ML. Surgery ofthe forefoot in rheumatoid arthritis.
Clin Orthop Rel Res 1960; 16: 136-40.
15 Kates A, Kessel L, Kay A. Arthroplasty of the forefoot. J
Bone joint Surg 1967; 49B: 552-7.
16 Barton NJ. Arthroplasty of the forefoot in rheumatoid
arthritis. J Bone joint Surg 1973; 55B: 126-33.
17 Craxford AD, Stevens J, Park C. Management of the
a comparison of conservative and
surgical methods. Clin Orthop Rel Res 1982; 166: 121-6.
Received 29 July 1996