The Cavus Foot in Athletes: Fundamentals of Examination and Treatment

The Cavus Foot in Athletes:
Fundamentals of Examination and Treatment
Sarang N. Desai, DO, Randolph Grierson, DO, and Arthur Manoli, II, MD
Athletes with cavus feet present unique challenges to the orthopedic surgeon. Continuous
high impact activity with this foot deformity leads to distinct injuries. Immediate recognition
of the athlete’s cavus feet and associated injuries allows prompt treatment and return to
sport. If not recognized, treatment will often fail. Injuries include stress fractures, ankle
instablility, impingement syndromes, and tendon disorders. Appropriate treatment requires
correction of the cavus deformity as well as the specific associated injuries. Nonoperative
treatment includes specialized orthotic shoe inserts. If a course of nonoperative treatment
fails, operative intervention is warranted. Operative treatment of the cavus deformity may
include a simple dorsiflexion first ray osteotomy or more complex reconstruction, including
a lateralizing calcaneal osteotomy. Correction or accommodation of the deformity as well
as the identification of the specific injury will likely lead to successful treatment and return
to a high level of competition.
Oper Tech Sports Med 18:27-33 © 2010 Elsevier Inc. All rights reserved.
KEYWORDS cavus, cavovarus, ankle instability, “peek-a-boo” heel
T
he cavus foot has been an enigmatic subject for many
years. The belief that cavovarus feet are the result of
neurologic lesions is deeply ingrained in the adult and pediatric orthopedic literature. Several potential causes of this
deformity have been described. Many of these do include
neurologic conditions such as polio, Charcot–Marie–Tooth
disease, Fredreich’s ataxia, and cerebral palsy. Other common causes include the residual effects of clubfeet and compartmental syndrome. Despite the popular belief that cavus
feet are a result of neurologic conditions, the single largest
population remains idiopathic. From our clinical observation, these adult cavus feet are idiopathic, and often have a
genetic component. Cavus foot deformities are common in
athletes. These types of feet present unique injuries and challenges to the orthopedic surgeon. The deformity and associated injuries should be recognized and treated appropriately.
The true incidence of cavus feet is unknown and multiple
factors contribute to this. While in residency, pediatric orthopedic training involves treating children with sequela of
neurologic disease. Many of these patients have severe cavovarus deformities. This has led to the notion that cavovarus
Michigan International Foot and Ankle Center, St Joseph Mercy Hospital,
Pontiac, MI.
Address reprint requests to Sarang N Desai, DO, Associated Orthopaedics
and Sports Medicine, 4031 W. Plano Parkway, Plano, TX 75093. E-mail:
[email protected]
1060-1872/10/$-see front matter © 2010 Elsevier Inc. All rights reserved.
doi:10.1053/j.otsm.2009.10.002
feet are more common to children, and only occur in patients
with neurologic disease. The result is cavus feet being deleted
from the adult differential diagnosis. Another contributing
factor is that most orthopedic surgeons have been taught the
“too-many toes” sign as an easy way to diagnose a posterior
tibial tendon deficient foot.1 The “peek-a-boo” sign is a similar easily performed test that diagnosis the cavus foot.2 This
is a more recent discovery and is often not taught while in
orthopedic training. Also, cavus feet are often bilateral, and
therefore lack a normal foot for comparison. This can also
make diagnosis more difficult.
Evaluation
The “peek-a-boo” sign was described in 1993 in an article
describing lower extremity contractures.2 We have used this
test for 15 years and have found it highly sensitive for identifying the subtle cavus foot. This test is performed with the
patient standing, with the feet aligned straight. These patients
generally have tight Achilles, and therefore have a tendency
to point their feet outward. We encourage the patients to look
down at their feet to ensure their feet point straight ahead.
When viewed from the front, the varus heel will be visualized
medially in a cavus foot (Figs. 1 and 2). A foot with physiologic heel valgus would not display this characteristic. The
amount of heel visualized medially should be compared with
the contralateral limb. Two causes of a false positive “peek27
28
S.N. Desai, R. Grierson, and A. Manoli II
Figure 1 Anterior standing examination shows bilateral “peek a boo”
heels and prominent first metatarsal head fat pads.
a-boo” sign include a very large heel pad and significant
metatarsus adductus. Heel varus should be confirmed with
posterior examination. When visualizing from the front, a
“bulging” first metatarsal head fat pad may also be seen medially.
After the identification of a varus heel, the Coleman block
test should be performed.3 This will identify whether the
subtalar joint is supple and will also assess whether a plantarflexed first ray is driving the heel varus. The Coleman
block test is performed by asking the patient to stand on a
wooden (or 1 in) block. The first ray is left off the block
medially. If the heel “corrects” to physiological valgus, the
varus hindfoot is supple and caused by a plantarflexed first
ray.3 This is often referred to as forefoot driven hindfoot varus
(Fig. 3). A strong contribution of the peroneus longus can
also be identified using another technique. This involves
placing one thumb under the first metatarsal head and the
other thumb across the remaining metatarsal heads. The patient is then asked to plantarflex the foot into the examiner’s
thumbs. With peroneus longus overdrive, there will be more
Figure 2 Posterior examination reveals hindfoot varus bilaterally.
Figure 3 Coleman block test reveals correction of hindfoot varus into
anatomic heel valgus.
force felt under the first metatarsal head as compared with the
lateral heads.4
Assessment of the Achilles mechanism is fundamental to
cavus foot evaluation. Part of that assessment involves performing the Silverskiold test that will isolate gastrocnemius
tightness from the rest of the triceps surae. When the ankle
cannot be passively dorsiflexed to neutral with the knee extended, but can be passively dorsiflexed to 5° of dorsiflexion
with the knee flexed, gastrocnemius tightness exists.5
Foot Morphology
and Biomechanics
A tight gastrocnemius and a plantarflexed first ray are central
to cavus feet.6 The repercussions of a plantarflexed first ray
can be significant. A plantarflexed position of the first metatarsal causes the medial aspect of the forefoot to strike the
ground first. When this occurs, the heel is forced into a varus
position to maintain a balanced three-point contact position
with the ground. Because of this, the hindfoot is unable to
reach maximal eversion. This in turn decreases the ability of
the subtalar joint to absorb and dissipate energy. The forefoot
and hindfoot, although initially flexible, can progress to stiff
then rigid over time. The forefoot then becomes fixed in a
pronated position and the hindfoot in a varus position. A
tight gastrocnemius can also significantly contribute to the
cavus posture. When the foot is in a planterflexed position,
the peroneous longus is placed at a biomechanical advantage
and the tibialis anterior at a disadvantage. With this relationship, the peroneous longus maintains the first ray in a plantarflexed position.7 This position of the first ray is at first
flexible, but over time can become stiff, and then rigid.
The cavus foot in athletes
29
the normal talocalcaneal angle. The foot height measured
from the top of the talar body to the floor will be greater in the
cavus foot compared to a normal contralateral side on the
lateral aspect.11 An AP radiograph of the feet will reveal forefoot supination (Fig. 5).
Other useful radiographs may include internal oblique of
the foot to evaluate for calcaneonavicular coalitions and
metatarsal fractures. Computed tomography scans can identify subtalar coalitions and degenerative changes of the ankle
and tarsometatarsal joints.
Associated Pathologies
Figure 4 Standing lateral radiograph shows an increased distance
between the inferior base of the fifth metatarsal and inferior medial
cuneiform. A break in Meary’s line and a posterior positioned fibula
is also noted.
Radiographic Evaluation
At our institution, radiographs consist of standing anteroposterior (AP) of both ankles (same cassette), both feet (same
cassette), and lateral views of each foot and ankle on the same
cassette.8 There are multiple consistent radiographic abnormalities common to cavus feet that can be identified. The
lateral view reveals a break in Meary’s line (axis of talus,
medial cuneiform, and first metatarsal) as a result of the plantarflexed metatarsal. Also in the lateral view, one observes a
high arch with an increased measured distance between the
inferior medial cuneiform and inferior fifth metatarsal base.8,9
A posteriorly positioned fibula may be seen due to an externally rotated ankle axis, as well as a dorsiflexed calcaneus.10
Although the calcaneus is dorsiflexed, the Achilles can still be
tight (Fig. 4).
With examination of the standing AP ankle (or foot) radiograph, several features are consistent. There is a decrease in
There are many conditions associated with cavus feet that
should be considered and treated appropriately. We often see
these associated pathologies in athletes given the repetitive
high-impact activity. These injuries can be debilitating and
can cost an athlete a successful career if not treated promptly.
Patients with cavus walk on the outer border of their feet
and their plantarflexed first ray. In the forefoot, the patient
may develop overload calluses under the first metatarsal head
and fifth metatarsal head or base. This can lead to hallux
sesmoiditis. Jones fractures of the fifth metatarsal and fourth
metatarsal stress fractures are common (Figs. 6-8). Other
common stress fractures are of the tibial or fibular shaft,
navicular, and medial malleolus. These fractures can be elusive, and we have found bone scans to be helpful. More
proximally, cavus feet are prone to peroneal tendon pathology. This may include tendonitis, subluxation, dislocation,
and tears (Fig. 9).
The peroneus brevis is more prone to injury compared to
the peroneus longus. An os perineum may also fracture leading to increased pain.12 Other common symptomatic foot
problems include a tight Achilles and tight plantar fascia.13,14
Ankle instability and recurrent ankle sprains in a patient
with cavus feet must be carefully considered. Standard repairs or reconstructions of the lateral ligaments may fail with-
Figure 5 Standing AP radiograph of the feet showing metatarsal overlap due to hindfoot supination and relative forefoot
pronation.
S.N. Desai, R. Grierson, and A. Manoli II
30
Treatment
An attempt to correct the apparent pathology without addressing the concordant foot deformity will often lead to
failure in treatment. This is particularly frequently observed
with lateral ligament reconstruction without correction of the
cavovarus deformity.
A trial of nonoperative treatment should be instituted
upon diagnosis. This consists of a specific cavus foot orthotic
as well as a gastroc stretching program. We demonstrate how
to perform these gastroc stretching exercises to each athlete
in the office. We recommend 20 repetitions 5 times a day for
each extremity.
Many athletes come to our office stating they have tried
orthotics, without alleviation of their symptoms, and in fact
that their symptoms were made worse. When the orthotic is
inspected, it is seen to be an orthotic designed for a planovalgus foot. We prefer a specific orthotic that has a few key
design features. First, there is a recess to allow for the plantarflexed first metatarsal head. This allows the possibility of at
least partial correction of the hindfoot, as demonstrated by
the Coleman block test. Even if the deformity is not flexible,
the recess will accommodate the plantarflexed first ray, and
therefore be more comfortable for the patient. Second, there
is an elevated heel to allow for equinus. Other features include a forefoot wedge that accommodates the valgus forefoot and a reduced medial arch. We have found that an or-
Figure 6 (A) AP radiograph displaying cortical hypertrophy consistent with fibular stress fracture. (B) Bone scan with increased uptake
at the site of the fibular stress fracture.
out correction of the varus heel and/or plantarflexed first ray.
Long-standing cases of cavus feet and ankle instability may
lead to varus ankle arthritis.15 Stress fractures of the medial
malleolus and navicular are also common (Fig. 10). External
rotation of the talus and tibia can also result in knee pathology. This posture of the lower extremity leads to excessive
stress on the lateral structures of the knee. Patients may complain of pain along the lateral collateral ligament or iliotibial
band.14,16,17 The varus strain may also result in medial compartment arthritis in long-standing cases.
Many other conditions may exist and should be recognized
in the comprehensive picture of the cavus foot (Table 1).
Figure 7 (A) Radiograph of fifth metatarsal stress fracture. (B) Radiograph of intramedullary screw fixation of stress fracture.
The cavus foot in athletes
31
Figure 9 Peroneal tears are common with cavus feet particularly tears
of the peroneus brevis.
thoses that fits snuggly against the medial arch is not only
painful for many athletes, but it does not allow for hindfoot
correction. In our practice, 3 of 4 patients have improved
symptoms with this orthoses. It would be reasonable to consider the use of such an orthoses in a symptomatic athlete
with a cavus foot shape.
Appropriate shoe wear is also imperative for these patients.
The shoe should allow for the prominent midfoot. This is best
done with a soft wide laced upper. A flared heel that is slightly
higher than the forefoot will help provide inversion stability.
A tight Achilles with subsequent extensor recruitment often
causes clawed toes in these patients. An extra depth toe box
will accommodate these contracted toes. Medial posting
should be avoided. Cosmetic cutaways and air chambers
weaken the shoe and can increase hindfoot instability and
Figure 8 (A) Subtle left cavus foot with visible “peek-a-boo” heel. (B)
MRI confirming navicular stress fracture. (C) Radiograph displaying
screw fixation of navicular stress fracture.
Figure 10 Cavus foot with medial malleolus stress fracture.
S.N. Desai, R. Grierson, and A. Manoli II
32
Table 1 Musculoskeletal Conditions Associated with the Cavus Foot
Associated Conditions
Fractures
Medial malleolus
Tibia shaft
Fibular
Navicular
Base of fourth metatarsal
Jones fracture of fifth metatarsal
Sesmoid
Os peroneum
Soft-tissue injuries
Peroneal tears/dislocations
Plantar fasciitis
IT band frication syndrome
Knee lateral collateral tears
Ankle lateral ligament instability
Subtalar instability
Achilles tendonitis
MTP synovitis
Arthritis
Varus ankle arthritis
Medial compartment knee
Midfoot
Other
Tight gastrocnemius muscle
Sesmoid overload, AVN
Exertional compartment syndrome
Metatarsus adductus
Calluses under first and fifth metatarsal heads
Large peroneal tubercle
Large distal fibula
MTP, metatarsophalangeal; AVN, avascular necrosis; IT, iliotibial.
should therefore be avoided. A cushioned neutral running
shoe is recommended.
When a trial of conservative treatment fails, operative intervention should be considered. It is imperative to identify
and correct all aspects of the cavovarus foot deformity. A
careful examination should reveal a supple versus rigid deformity, which is paramount in the successful treatment of
these patients. As mentioned previously, a contracted gastroc
is almost universally found in the cavovarus foot. We prefer
to treat this with a modified Vulpius type lengthening. A
medial incision approximately 15 cm from the tip of the
medial malleolus is created, and the sural nerve is first identified. The gastrocnemius tendon alone, and often the soleus
fascia, is then lengthened in a pie-crust manner.18,19
In the case of peroneal overdrive with a flexible first ray, a
peroneus longus to brevis transfer is performed at the peroneal tubercle. The distal stump of the longus is transferred to
the brevis tendon to avoid formation of a dorsal bunion. To
address the plantarflexed first metatarsal, which drives a cavus deformity, we prefer a dorsal closing wedge V-type osteotomy secured with a 4.0-mm screw, notching the dorsal
cortex to prevent fracture.20,21 With a more pronounced forefoot pronation deformity, a V-type osteotomy of the second
and third metatarsals, and possibly the midfoot may be required.
As highlighted earlier, the cavovarus foot generally
progresses from a supple deformity to a rigid deformity over
time. In instances when the varus heel does not correct with
a Coleman block test, a lateralizing calcaneal osteotomy is
performed along with a dorsiflexion osteotomy of the first
metatarsal. An oblique incision is made through the midportion of the calcaneal tuberosity, and the osteotomy is done
perpendicular to the axis of the tuberosity. Cuts created too
far posterior will penetrate Haglund’s prominence and bursa,
whereas those too far anterior may enter the subtalar joint.
The heel is translated 5-10 mm medially and secured with 2
stacked 6.5-mm screws.
With an advanced cavovarus deformity, the magnitude of
the deformity can become significant and the tissue stiff.
When this occurs, a triple arthrodesis is required. The articular cartilage of the calcaneocuboid, subtalar, and talonavicular joints are denuded, and they are secured with 6.5-mm
lag screws. The heel must be placed into mild valgus, and the
forefoot derotated through the Chopart joints from its initial
pronated position.22 A common error is correcting heel varus
without correcting the forefoot deformity. When the heel is
moved into valgus the first ray planterflexion increases, and
this must be addressed or the heel will move back into varus
after surgery.
As noted previously, many conditions may be associated
with the cavovarus foot shape. Some of these conditions may
require operative treatment. Fractures are treated with rigid
internal fixation using solid screws, or excision for sesmoid,
or os peroneum fractures. Jones fractures are common, and at
our institution, we treat these with rigid internal fixation with
or without bone grafting (Fig. 7).
Recent literature has supported acute fixation of Jones fractures.23 We also prefer to treat stress fractures of the navicular
with rigid internal fixation (Fig. 8).
We believe aggressive treatment of these stress fractures
provides a more favoerable biomechanical environment for
the fracture to heal, and allows the athlete to return to athletic
activity faster. Along with internal fixation, we also address
the cavus through either conservative or operative means as
discussed earlier. We often see athletes who have failed multiple operative procedures for these fractures. This can be
devastating for the professional as well amateur athlete. The
importance of correcting the cavus deformity cannot be overemphasized.
Peroneal tendon tears, subluxation, or dislocation should
be treated appropriately. An incision is made just posterior to
the posterior border of the fibula at the distal aspect of the
superior peroneal retinaculum. The retinaculum is opened at
its fibular insertion. Longitudinal tears are repaired. An extensively degenerated peroneus longus tendon is transferred
to the peroneus brevis. If a shallow or convex groove is identified, it is deepened. We prefer to do this by drilling multiple
2.0-mm holes in an oblong shape, and impacting this cortical
bone. The superior peroneal retinaculum is repaired through
3 drill holes in the fibula, and 2 horizontal mattress stitches
with a heavy nonabsorbable suture. In this way we achieve a
The cavus foot in athletes
33
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Figure 11 Illustration showing the dorsal talar osteophyte common
with ankle impingement.
secure repair, and also are able to advance a lax retinaculum.
If the patient has greater tenderness at the peroneal tubercle,
the incision is centered distally over the tubercle. Tears are
repaired, and a large peroneal tubercle is removed.
With recurrent ankle sprains the lateral ligaments should
be tightened with possible augmentation. We perform a
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