Document 6475155

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Document 6475155
FOOT & ANKLE INTERNATIONAL
Copyright  2008 by the American Orthopaedic Foot & Ankle Society
DOI: 10.3113/FAI.2008.0000
Current Concept Review: Metatarsalgia
Norman Espinosa, MD; Ernesto Maceira, MD; Mark S. Myerson, MD
Zurich, Switzerland
INTRODUCTION
forefoot and the etiology of central metatarsalgia we refer to
the “rocker concept” which originates from gait analysis.34
The “first-rocker” (0% to 10% of the cycle) includes the
period between heel strike and initial ground contact of
the forefoot; it is controlled by the ankle dorsiflexors
and allows the tibia to rotate in relation to the calcaneal
tuberosity. Once foot flat is achieved, the tibia glides over
the talus.26,27 This period, the midstance or “second-rocker”
(10% to 30%), is controlled by eccentric contraction of the
gastrocsoleus. Increased loading of one or more metatarsal
heads during the midstance phase of gait is a common
cause of metatarsagia. This situation can occur when there is
increased plantarflexion of one or more metatarsals leading
to localized forefoot overload and resulting in increased
pressure at the corresponding metatarsophalangeal (MTP)
joints. The “third-rocker” (30% to 60% of the cycle) starts
with heel rise and is initially controlled by gastrocsoleus
muscle activity. “Third-rocker” (or propulsive metatarsalgia)
may occur during heel rise and is linked to metatarsal length.
Metatarsals that are disproportionately long will subject the
corresponding metatarsal head and surrounding soft-tissues
to more repetitive loading.
Metatarsalgia refers to localized or generalized forefoot
pain in the region of the metatarsal heads.10 The term
is frequently used as a “waste-basket” diagnosis for forefoot pain. Often this pain is plantar, beneath the metatarsal
heads, and arises from either mechanical or iatrogenic
causes.45 The surgical treatment of metatarsalgia remains
controversial, with multiple procedures described in the
literature.5,14,20,21,48 A thorough understanding of the biomechanics of the forefoot and the underlying pathology of
the particular type of metatarsalgia affecting the patient
is a prerequisite to selecting the proper treatment. This
review focuses on central metatarsalgia, defined as pathology
involving the second through fourth metatarsals. It will
provide a basic understanding and classification of central
metatarsalgia, and discuss the options for the successful
management of this challenging clinical entity.
BIOMECHANICAL CONCEPTS AND CLINICAL
IMPLICATIONS
A fundamental etiological component of metatarsalgia is
the repetitive loading of a locally concentrated force in the
forefoot during gait. An overload of weightbearing forces
may affect the entire forefoot or an isolated area (e.g., a
metatarsal head) when the foot is plantigrade. During the
stance phase of gait, the plantigrade foot provides stable
support, while the leg moves over it to propel the body
forward. In order to understand the mechanics of gait in the
No benefits in any form have been received or will be received from a commercial
party related directly or indirectly to the subject of this article.
Corresponding Author:
Norman Espinosa, MD
Department of Orthopaedics
University of Zurich
Balgrist
Forchstrasse 340
8008 Zurich
Switzerland
E-mail: noresp@gmx.net
For information on prices and availability of reprints, call 410-494-4994 x226
Norman Espinosa, MD
871
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ESPINOSA ET AL.
Foot & Ankle International/Vol. 29, No. 8/August 2008
Table 1: Level of evidence and grades of recommendation
Level of Evidence
— Level I: high quality prospective randomized clinical
trial
— Level II: prospective comparative study
— Level III: retrospective case control study
— Level IV: case series
— Level V: expert opinion
Grades of Recommendation (given to various
treatment options based on Level of Evidence
supporting that treatment)
— Grade A treatment options are supported by strong
evidence (consistent with Level I or II studies)
— Grade B treatment options are supported by fair
evidence (consistent with Level III or IV studies)
— Grade C treatment options are supported by either
conflicting or poor quality evidence (Level IV
studies)
— Grade I when insufficient evidence exists to make a
recommendation
CLASSIFICATION AND CLINICAL PRESENTATION
In order to appreciate the rationale behind the various
treatment options, a framework differentiating metatarsalgia
based on etiology is crucial. Table 2 divides metatarsalgia
into three categories and lists the various conditions associated with each subtype.
Primary metatarsalgia
Primary metatarsalgia refers to symptoms arising from
innate abnormalities in the patient’s anatomy leading to
overload of the affected metatarsal. These anomalies may
include a disproportionately long or plantarflexed metatarsal
relative to the remaining rays of the forefoot.14,15,41,52
Discrepancies in metatarsal length contribute to primary
metatarsalgia, with a long second metatarsal being the most
frequent anomaly. Patients with primary metatarsalgia often
present with pain during the propulsive phase of gait (“thirdrocker” metatarsalgia). The pain is localized underneath the
prominent metatarsal head. The plantar soft tissue can be
swollen and inflamed. With continuing pressure at this locus,
the overlying skin will react and establish an intractable
plantar keratosis (IPK).
Table 2: Synopsis of the different types of metatarsalgia
METATARSALGIA
PRIMARY METATARSALGIA
Insufficiency of the first ray
Excess of metatarsal plantar slope or plantarflexed
metatarsal bone
Metatarsal head protuberance
Arthritis, Tumor, Infection, Congenital, Hereditary
Metatarsal length discrepancy
Equinus
Pes cavus, Contracture of gastroc-soleus complex
SECONDARY METATARSALGIA
Metabolic disorders
Gout
Systemic disorders
Rheumatoid arthritis
Arthritides of MP joints
Trauma
Neurological disorders
Morton’s neuroma, Tarsal tunnel syndrome
Freiberg’s disease
IATROGENIC METATARSALGIA
Failed hallux valgus surgery
Failed MP-I fusion
Failed corrective metatarsal osteotomies (indication
vs. technical error)
Failed shortening of 2nd ray
Foot & Ankle International/Vol. 29, No. 8/August 2008
Primary metatarsalgia can also result from a plantarflexed
metatarsal.13 Plantarflexion of a central metatarsal may occur
as a result of a malunited fracture or due to a severe
hammertoe deformity. Patients may report pain during the
stance phase of gait (“second-rocker” metatarsalgia). A
distinguishing feature of second-rocker keratoses is their
strictly plantar location in relation to the corresponding head.
A well-localized IPK directly beneath the head (with no
distal extension towards the toe) may occur when only one
metatarsal is plantarflexed. When multiple metatarsals are
plantarflexed, several discrete keratoses appear. In thirdrocker metatarsalgia, the keratoses are not located directly
beneath the metatarsal, but instead plantar and distal to the
affected heads. External rotation of the limb at final stance
creates a shear effect that manifests as a rounded appearance
of the keratosis that usually spans several heads. The result
most often is a large and diffuse area of hyperkeratosis, which
extends distally toward the toes. Keratoses associated with
first ray insufficiency syndromes (i.e., hallux valgus, short
first metatarsal) exhibit third-rocker features, but in cases of
concomitant MTP joint subluxation, a second-rocker lesion
appears as well within the previous contour of the thirdrocker keratosis.
Other causes of primary metatarsalgia include an abnormally enlarged metatarsal head or condyle. This deformity occurs infrequently and may result from infection,
tumor, congenital malformation or other hereditary factors.
Forefoot equinus, as seen in a cavus foot, or posterior
equinus,13,40 (e.g., contracture of the gastrocsoleus complex)
may also cause primary metatarsalgia. Of note, a gastrocsoleus contracture is another cause of a diffuse IPK spanning
more than one metatarsal head.
Secondary metatarsalgia
Systemic conditions that can lead to secondary metatarsalgia include trauma,28 inflammatory arthropathy, gout,6,20
arthritides and instability of the MTP joints,13,50 Morton’s
neuroma,11,36 tarsal tunnel syndrome48 and Freiberg’s infraction.13 Not all of these conditions directly affect the
metatarsal, and instead indirectly overload the forefoot.
Trauma may shorten, elevate or plantarflex a metatarsal fracture and cause pain, but an associated dislocation of the
MTP joint or periarticular soft tissue injury may contribute
to pain. The effect of metabolic disorders such as gout or
rheumatoid arthritis may cause the MTP joint to hyperextend, resulting in a shift of plantar pressure to the metatarsal
heads. This shift of plantar pressure combined with distal
migration of the plantar fat pad may lead to pain. Atrophy
of the fat pad secondary to a systemic condition may also
cause central metatarsalgia. The same forces that overload the
metatarsal head and surrounding soft-tissues can also injure
the plantar digital nerve and result in pain similar to mechanical metatarsalgia.
METATARSALGIA
873
Iatrogenic metatarsalgia
Iatrogenic metatarsalgia can be troublesome and is more
prevalent than previously thought.12,45 This type of central
metatarsalgia may arise from malalignment of metatarsal
osteotomies or from a metatarsal head resection. Nonunion
or delayed union of a metatarsal after reconstructive surgery
or errors in positioning or fixation of the osteotomy can all
lead to transfer of the forces of weightbearing and overload
of the adjacent metatarsals.
One of the most common errors is the iatrogenic shortening of the second metatarsal because of nonunion, fracture
or incorrect choice of lesser metatarsal osteotomy. Elevation of the ray may lead to third-rocker metatarsalgia, while
shortening it may lead to second-rocker metatarsalgia. Sometimes metatarsal heads are only partially resected, leaving
remaining bone spurs that lead to punctiform peak pressures under the skin. The same problem is encountered if
the phalangeal base is improperly removed. Finally, hallux
valgus surgery that results in elevation of the first ray can
cause a shift of plantar pressures to the lesser metatarsals.
CLINICAL AND RADIOGRAPHIC EVALUATION
The patient’s foot should always be evaluated while
standing. This helps demonstrate the magnitude of any deformity. Inspection of the plantar aspect of the foot may reveal
either localized or diffuse patterns of hyperkeratosis. The toes
are examined and the range of motion documented, along
with plantarflexion and dorsiflexion of the ankle joint to
assess contractures of the extensor or flexor tendons. Gastrocnemius or gastrocsoleus contracture is tested according to
the method described by Silfverskj¨old.53 Palpation of each
MTP joint and intermetatarsal web space is essential. Clawtoes with synovitis or even subluxation of the MTP joints
is a common finding. The neurovascular status should be
carefully evaluated with specific focus placed on the microcirculation of the lesser toes. Palpation of the metatarsal
heads and the plantar condyles is often possible, but is easier
in advanced stages of disease when the plantar fat pad is
displaced distally.39 Gait analysis can be helpful in determining the type of metatarsalgia pattern and to detect the
regions of overload.34
Standard weightbearing foot radiographs including an
anteroposterior, internal oblique and lateral view are sufficient to evaluate the forefoot.37 The relative length of each
metatarsal and the overall metatarsal cascade should be
evaluated.37,67 On the lateral view, the declination of the
metatarsals can be assessed. Meanwhile, the internal oblique
view allows for better visualization of subluxed or dislocated
MTP joints. In rare cases, with an occult entity underlying
the metatarsalgia, magnetic resonance imaging (MRI) can aid
in establishing the correct diagnosis.
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ESPINOSA ET AL.
TREATMENT
The treatment of central metatarsalgia should address the
underlying pathology, as well as the expectations, of the
patient. Conservative treatment should always be maximized
before considering surgery in the management of this condition.
Conservative treatment
Not much scientific literature exists to confirm the effectiveness of conservative treatment for the treatment of
central metatarsalgia. Nevertheless, such measures often
meet with success and have the additional benefit of not
compromising future treatment. Conservative treatment may
include stretching exercises, shoe modification, shaving of
the callosity, rest, use of metatarsal pads and molded insoles,
corticosteroid injections, and anti-inflammatory medications.
Stretching exercises
Stretching exercises in patients suffering from gastrocnemius or gastrocnemius-soleus tightness are intended to
lengthen the triceps surae muscles and thereby decrease
the pressure at the forefoot. These exercises are best
performed by the patient after education by a physical
therapist.12 Gajdosic and coworkers demonstrated that a 6week stretching program increased the maximal ankle dorsiflexion angle and length extensibility, as well as the passive
resistive properties throughout the full stretch range of
motion. They further demonstrated that stretching enhances
the dynamic passive length and passive resistive properties (Level I study).16 However, this study did not examine
patients with central metatarsalgia. Thus insufficient data
exists to render a proper recommendation for its use in central
metatarsalgia (Grade I recommendation).
Shoe modifications and padding
The goal of shoe modification is to distribute pressure
more evenly over the forefoot and among the metatarsal
heads. The shoe should be comfortable and fit correctly.
Wider toe boxes can resolve pain in patients suffering
from lesser toe deformities, MP joint instability, hard and
soft corns.10 Stretching the shoebox overlying the fifth
metatarsal head can help to reduce pain in patients with
bunionette deformites. Lower heel height, an excavated
insole, external metatarsal bar, and a rocker-bottom sole
can help improve symptoms in many patients with central
metatarsalgia. Generally, accommodative insoles may redistribute pressure under the foot while functional orthoses are
intended to control abnormal intersegmental motion; both
of them may be useful in the non-operative management of
metatarsalgia.4,28,29,31,47
The same spectrum of applications pertains to the use
of orthotic arch supports,15,18,55 which includes padding of
the insole just proximal to the painful metatarsal head.23,65
Foot & Ankle International/Vol. 29, No. 8/August 2008
This padding serves to distribute force away from a prominent metatarsal head. Experimental studies support their
effect in decreasing pressure underneath the metatarsal
heads.7,23 Conservative treatment may be successful if
capsulitis and instability are diagnosed early. In a prospective study performed by Kang et al., 13 patients (18 feet)
with secondary metatarsalgia were investigated regarding the
use of metatarsal pads. The group found that the successful
decline in the pressure time integral and maximum peak pressures under the second metatarsal head after metatarsal pad
application was correlated to subjective pain improvement
(Level II evidence). Based on the evidence provided from
these Level III and IV studies, a Grade B recommendation applies to the use of shoe modification and padding for
central metatarsalgia.
Shaving of callosities
Although the trimming of a plantar callus may reduce
the thickness and thereby reduce the pressure over a painful
IPK, no evidence-based information exists about the effect
of shaving calluses for the treatment of metatarsalgia. A high
rate of recurrence of the callosity exists because it does
not address the underlying pathology. Thus, only a Grade
I recommendation can be assigned.
Surgical treatment
If non-operative treatment is unsuccessful, surgical treatment may be warranted. The primary goal of surgery is to
restore a normal distribution of pressure within the forefoot.
As a rule, it is important to restore a harmonic Maestro
curve,37 to restore the correct metatarsal slope, and to provide
adequate ground contact for the metatarsal heads. It is also
important to understand the effect of metatarsal osteotomies
on forefoot biomechanics to avoid possible complications.
A variety of surgical treatments for metatarsalgia have been
described. They include plantar condylectomy, distal oblique
metatarsal osteotomy, diaphysieal metatarsal osteotomy,
flexor to extensor transfer for the management of lesser MTP
joint instability, and metatarsal head resection.
Plantar condylectomy
Plantar condylectomy of the metatarsal is rarely indicated for central metatarsalgia. It may be considered for
the treatment of well-localized IPKs. A major disadvantage of a plantar condylectomy is the possibility of destabilizing the plantar plate. The loss of capsuloligamentous
restraint may lead to iatrogenic instability and arthritis of
the MTP joint. Condylectomy is not indicated for larger
IPKs: a distal metatarsal osteotomy may be the more logical
approach.9,51 Conklin performed a retrospective review of
86 basal hemiphalangectomies in 52 patients (Level IV
evidence).41 In his series 60% of the patients had total relief
of pain; however, 29% were classified as dissatisfied. An
extensor tenotomy increased the satisfaction rate and was
found to decrease the radiographic sagittal angulation of the
Foot & Ankle International/Vol. 29, No. 8/August 2008
toe. The current body of evidence is insufficient (Grade I
recommendation) to support to use of plantar condylectomy
for central metatarsalgia.
Distal oblique metatarsal osteotomy
Distal metatarsal osteotomies, such as the Weil and the
Maceira triple osteotomies are designed to restore the physiologic cascade of the lesser metatarsals and evenly redistribute
the forces of weightbearing at the forefoot. These osteotomies
reposition the metatarsal head through shortening, elevation
or both.3,22,33,35 The Weil osteotomy provides a longitudinal decompression and is particularly relevant in patients
suffering from metatarsalgia due to an excessively long
metatarsal. The main problem associated with the original
design of the Weil osteotomy is plantar translation of the
metatarsal head during shortening. This translation can lead
to transfer metatarsalgia, dorsiflexion contracture of the MTP
joint, and persistent pain.
Modifications of the Weil osteotomy have been introduced
in order to prevent excessive shortening of the metatarsal and
concomitant plantarflexion of the head. Melamed et al. found
that modifying the Weil osteotomy by adding a dorsal oblique
bone wedge resection resulted in moderate shortening and
essentially no plantar displacement of the head.63 Additionally, they found that removal of each 1 mm of dorsally based
wedge resulted in 0.5 mm of shortening and 0.6 mm of elevation and that the amount of shortening depended also on the
angulation of the osteotomy. Based on those results, Maceira
and coworkers introduced the so-called “triple-osteotomy”.35
This modified osteotomy affords precise and accurate shortening of the metatarsal without unwanted plantar translation
of the heads. The triple osteotomy also preserves the relationship between the dorsal interossei and transverse axis of
rotation of the MTP joint to avoid an extension deformity.
An alternative method to elevate the head during shortening
is to use a double layer Weil-osteotomy.1,30
Results and complications
Hofstatter et al.22 performed a prospective study and evaluated the short- to long-term results of the Weil osteotomy for
the treatment of metatarsalgia with subluxated or dislocated
lesser MTP joints in 25 feet (Level II evidence). Good to
excellent results were achieved in 88% of cases at a followup
of 7 years. The AOFAS score significantly improved from
48 to 83. The authors found that the procedure significantly
reduced pain, diminished isolated plantar callus formation
and increased walking capacity. Recurrent dislocation of the
metatarsophalangeal joint was seen in 12% of cases. The
authors concluded that although floating toes and restricted
movement of the metatarsophalangeal joint may occur, the
Weil osteotomy was safe and effective. Retrospective reviews
by Beech et al.,3 Vandeputte,66 and Trnka et al. (Level IV
evidence)59 also identified good to excellent results in most
patients undergoing a Weil osteotomy.
METATARSALGIA
875
A pitfall of the Weil osteotomy is the difficulty of
obtaining the correct amount of shortening of the metatarsal.
Insufficient shortening leads to persistent pain and excessive
shortening causes transfer metatarsalgia in the adjacent
metatarsals. Stiffness of the MTP joint is another potential
problem associated with a Weil osteotomy. This drawback
predominately occurs at the second MTP joint. Non-union
and malunion, although infrequent, may also occur with this
procedure.42,45
A floating toe, defined as a toe that does not contact the
ground, is a postoperative complication that can severely
compromise the effectiveness of a distal metatarsal osteotomy. According to Migues et al., the incidence of a floating
toe following Weil osteotomies may be as high as 28.5%.
If proximal interphalangeal joint arthrodesis is performed
concurrently with the osteotomy, the rate increases to 50%.42
Excessive plantar translation of the distal fragment has
been identified as a causative factor because it shifts the
center of rotation of the MTP joint plantarwards.63 This
change reverses the effect of the interossei muscles and
they become dorsiflexors instead of plantarflexors of the
MTP joint. Methods proposed to minimize the occurrence
of a floating toe include lengthening the extensor tendon,
performing the osteotomy parallel to the ground combined
with the dorsal wedge resection technique, adding a flexorto-extensor transfer, and inserting a Kirschner-wire across
the joint.60,63
A recent cadaveric study performed by Khalafi et al.33
evaluated plantar pressure changes associated with Weil
osteotomy of the second metatarsal neck. They were
observed an average decrease in pressure beneath the second
metatarsal from 70.6 to 45.1 kPa in neutral and 813.0
to 281.4 kPa in heel rise, representing statistically significant decreases of 36% and 65%, respectively. The authors
concluded that the Weil osteotomy effectively offloads the
second metatarsal head at neutral and heel rise positions.
Despite the challenges associated with the Weil osteotomy,
this procedure has provided effective pain relief in the
management of metatarsalgia in several retrospective series.
The evidence supports a Grade B recommendation for the
use of distal metatarsal osteotomies in the management of
central metatarsalgia.
Diaphyseal metatarsal osteotomy
A diaphyseal osteotomy has also been endorsed as a viable
treatment for central metatarsalgia associated with a long
metatarsal. Helal19 introduced an osteotomy of the midshaft
of the metatarsal similar to the Meisenbach osteotomy. The
difference between the two procedures lies in the orientation
of the osteotomy. Helal proposed a more obliquely directed
cut from dorsal-proximal to plantar-distal. Helal emphasized
the importance of preserving the medial and lateral tubercles.
These tubercles are the points of attachment for the collateral
and the plantar ligaments and stabilize the distal fragment
after the osteotomy. The original description of the Helal
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ESPINOSA ET AL.
osteotomy did not include internal fixation, and subsequently
the distal fragment shifted and proximal translation of
the distal fragment was observed when the patient stood
on the foot. The location of the osteotomy in diaphyseal
bone is associated with an increased risk of delayed union
and nonunion.12,62 Although modifications of the original
procedure have been introduced by Mann and DuVries, and
Turan and Lindgren,64 the overall results of a diaphyseal
osteotomy have not improved substantially.
Results and complications
Helal retrospectively reviewed 47 feet in 38 patients
treated with his osteotomy (Level IV evidence).19 He
reported mixed results. Six patients continued to experience
restriction in walking while five patients had postoperative
complications that included infection, nonunion and stiffness.
Winkler68 retrospectively reviewed a large series of 336 Helal
osteotomies in 114 patients (Level IV Evidence). Seventytwo percent of patients reported good relief of their pain.
When the authors evaluated their failures with pedobarographic measurements, the majority were due to an unequal
distribution of weight in the forefoot. Two patterns of incorrect weightbearing were recognized: excessive weightbearing
on the untreated adjacent metatarsals, and diffuse overload
of the entire forefoot secondary to loss of weightbearing
support caused by contracted MTP joints. Similar results
were reported by Slavik and Kubice (Level IV evidence).54
Trnka and colleagues61,62 concluded that the Helal osteotomy
is not an acceptable procedure for correcting metatarsalgia
caused by dislocation of the MTP joint and that a Weil
osteotomy should be performed in such a case. This retrospective study compared the outcomes of 30 patients treated
with either the Weil or Helal osteotomy for metatarsalgia
resulting from dislocation of one or more lesser MTP joints
(Level III evidence). The authors found a 30% rate of malunion and a 14% rate of nonunion in patients treated with
Helal osteotomies.
Retrospective reviews by Pedowitz,46 Winson,69 and
Idusuyi25 each identified unacceptably high rates of complication with the use of the Helal osteotomy. Pedowitz
concluded that this osteotomy should not be used for an
IPK associated with fixed toe deformity.46 Winson et al.69
investigated the outcome of 124 feet. Almost 50% had a
metatarsal head prominence or symptomatic callus postoperatively. Additionally, 30% suffered from transfer-type lesions
with callosities under adjacent metatarsal heads. Similarly,
in the study of Idusuyi et al.25 half of the patient population
continued having pain 10 years after Helal osteotomy.
Multiple retrospective studies (Level III evidence) have
reported that patients who undergo a Weil osteotomy
for treatment of overload metatarsalgia have a substantially higher satisfaction, lower incidence of recurrent
metatarsalgia, and fewer transfer lesions than those treated
with a Helal osteotomy.25,62,54,68,61,46,69 Furthermore, those
managed with the Weil osteotomy had a higher percentage
Foot & Ankle International/Vol. 29, No. 8/August 2008
of radiographic reduction and maintenance of correction of
their MTP joint dislocation than those managed with the
Helal osteotomy. Overall, this body of evidence is insufficient
to support the use of the Helal osteotomy for patients with
metatarsalgia and constitutes fair evidence (Grade B recommendation) to support preference for the Weil osteotomy over
the Helal osteotomy.
Metatarsal head resection
Although most surgeons have abandoned this procedure,
it continues to be employed in cases of severe metatarsalgia
caused by underlying rheumatoid arthritis, elderly patients
with low physical demands,2,32,38 and following severe iatrogenic forefoot deformity where limited options for salvage
exist. Retrospective studies assessing patients with advanced
MTP joint destruction secondary to rheumatoid arthritis
show a benefit from metatarsal head resection (Level IV
evidence)24,43,56 . The drawbacks associated with metatarsal
head resection is the potential for transfer lesions to develop
beneath the adjacent metatarsals, cosmetic disturbances,
dorsal contracture of the toes, as well as instability or floppiness of the forefoot. Isolated resection of the fifth metatarsal
head may be considered in the case of a severely painful
bunionette deformity, but should be avoided in patients with
heel varus. Metatarsal head resection is still used to resolve
non-healing plantar forefoot ulcers in diabetic patients.49
Overall, the published experience with metatarsal head resection deals with diabetic and rheumatoid patients,24,43,564356
and the evidence is insufficient (Grade I recommendation) to
support its use in any of these groups of patients.
Flexor-to-Extensor transfer for the treatment of
metatarsophalangeal joint instability of the second toe
Originally described for the treatment of a flexible clawtoe
deformity, transfer of the flexor digitorum longus tendon to
the dorsum of proximal phalanx has become increasingly
popular in order to treat painful instability of the second
MTP joint.8,17,44
Results and complications
Although several studies have confirmed the effectiveness
of a flexor-to-extensor transfer, these investigations report
variable levels of satisfaction, with results ranging from 51%
to 89%. Also, incomplete correction after tendon transfer in
patients with subluxated MTP joints has also been reported
in the literature.5844 In a retrospective series reported by
Myerson and coworkers (Level IV evidence), a total of
64 feet (59 patients) were evaluated after tendon transfer
for painful instability of the second toe, with an average
followup of 45 months. A cross-over toe was present in
87% of cases with a stage II deformity being the most
common. Seven cases had vertical subluxation of the joint.
In additional to a flexor-to-extensor tendon transfer, a second
metatarsal Weil osteotomy was done in 29 feet, a proximal
interphalangeal (PIP) joint resection arthroplasty in 22 feet,
Foot & Ankle International/Vol. 29, No. 8/August 2008
and a PIP joint fusion in nine feet. At final followup 37%
had residual second MTP dorsiflexion contracture while 16
feet had persistent medial deviation. The second toe was
stable to stress manipulation in 46 feet. Complications arose
in twenty cases. Twenty-five patients (29 feet) were very
satisfied, 15 satisfied with minor reservations, six with major
reservation, and 14 patients were unhappy with the outcome.
The authors concluded that although the function of the
second toe improved as a result of pain relief in most patients,
a substantial number remained dissatisfied due to residual
stiffness of the toe. They stated that the procedure must be
used with a full understanding of potential complications and
patient dissatisfaction Generally, complications experienced
after this procedure are uncommon. However, swelling and
stiffness of varying degrees, transient numbness of the
involved toes; hyperextension of the DIP joint and recurrence
of flexion at the PIP joint may occur and impair overall
outcome. Based on the results from these Level III and Level
IV studies, fair evidence (Grade B recommendation) exists
to support the use of a flexor-to-extensor tendon transfer in
paints with metatarsalgia due to painful instability of the
lesser MTP joints.
SUMMARY
The optimal treatment of metatarsalgia remains controversial. Principles that underlie the diagnosis and management
of metatarsalgia appear to include:
1. Concentrated repetitive loading over a prominent
metatarsal head during the second and third-rocker
stages of gait leads to chronic irritation to skin, softtissues, MTP synovium, and/or digital nerves producing
localized forefoot pain characteristic of metatarsalgia.
2. Metatarsalgia can be considered primary or secondary.
Primary metatarsalgia results from metatarsal head
overload due to intrinsic causes such as a long
metatarsal, a plantarflexed metatarsal, or a dorsiflexed first ray leading to second metatarsal overload.
Secondary metatarsalgia results from extrinsic causes
such as a metatarsal fracture, malunion, Freiberg’s
infraction, and the sequelae of metabolic diseases such
as rheumatoid arthritis and gout.
3. Metatarsalgia is often associated with subluxed and
dislocated lesser MTP joints. These deformities lead to
distal migration of the plantar fat pad and predispose to
increased loading over the prominent metatarsal head.
4. Many patients with metatarsalgia can be treated nonoperatively with good success. Non-operative treatment
may include: comfortable shoes with a wide toe box,
a comfortable insert with a metatarsal pad or bar to
disperse the force more widely over the forefoot, corticosteroid injections, anti-inflammatory and/or regular
shaving of a prominent callus.
METATARSALGIA
877
5. Metatarsalgia secondary to overload of one or more
metatarsal heads can often be treated effectively with
surgery if non-operative management is unsuccessful.
Surgery is designed to relieve localized forefoot force
concentrations often by repositioning the metatarsal
head via a metatarsal osteotomy and/or by correcting
subluxation of an MTP joint.
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