Fibula
Tibia
INJURY & REHAB
PLANTAR
FASCIITIS
Plantar fasciitis is one of the most common
causes of plantar heel pain. Clinical lead
podiatrist, Jai Saxelby, provides a technical
insight into the condition, and details
treatment therapies.
he plantar fascia, also known as
the plantar aponeurosis, is a
visco-elastic structure that spans
the underside of the foot (from the heel to
the toes) and plays a significant role in the
weight-bearing foot, both statically and
dynamically. Its design is equipped to resist
elongation under tensile load, resulting in
the storage of elastic energy. Working
synergistically with the Achilles tendon, it
absorbs energy during initial weight-bearing,
then returns the energy during propulsion,
acting like a spring.
Measurement of oxygen consumption
during running suggests the storage of
elastic energy in muscle and tendons
saves about 50% of the metabolic energy
that would otherwise be needed. Box
1 explains the foot model known as the
‘windlass mechanism’, which illustrates the
relationship between the foot joints and the
plantar fascia, and how to test it yourself.
T
Windlass mechanism and test
The anatomy involved is the medial slip of
the plantar fascia and the medial (inside of
the foot) arch. The plantar fascia originates
from the medial tubercle of the heel and
inserts into the base of the proximal phalanx
of the first metatarsophalangeal joint (MTPJ).
The windlass test requires the big toe to be
dorsiflexed (upward movement); this tightens
the plantar fascia due to it being wound
around the first metatarsal head, effectively
drawing the first MTPJ and heel together,
thereby ‘shortening’ the arch (see Box 1).
How to use the windlass test
Stand the client on a step, allowing the toes
to overhang. Apply an upward force to the big
toe and feel the tension in the plantar fascia;
Achilles
tendon
Talus
Navicular
Cuneiforms
Calcaneus
Irritated and inflamed
plantar fascia
approximately 65 degrees is regarded as
a normal range of movement (Box 1a). The
more restricted the movement, the greater the
tension in the plantar fascia – in some cases
it may even provoke symptoms. There are
various causes that result in this restriction,
including: bony deformity (hallux rigidus);
excessive foot pronation; and restricted ankle
joint movement, e.g., tight calves.
Function of the windlass in the
gait cycle
During initial contact, the windlass unwinds,
the arch elongates, and the fascia goes taut
(Box 1b). Synchronous with this, the foot
pronates (heel everts, midfoot pronates and
the forefoot inverts).
During propulsion, the windlass tightens
and the arch shortens. Synchronous
with this, the foot supinates (heel inverts,
midfoot supinates and the forefoot everts)
(Box 1c).
What is plantar fasciitis?
Plantar fasciitis is one of the most common
musculoskeletal foot injuries, but is often
used as a cover term for all plantar heel
pain. The evidence suggests that the
condition is a chronic degenerative/
reparative process caused by repetitive
micro-trauma to the fascia over time. Due
to this, the term plantar fasciopathy is
now commonly used.
Box 2 details the anatomy, the location
of the pain, and the clinical signs and
symptoms used to make a clinical diagnosis
of plantar fasciitis. Diagnostic imaging,
such as an ultrasound or MRI, has been
shown to be useful for confirming diagnosis.
Plantar fasciitis is prevalent in athletic,
military and non-athletic populations and is
Metatarsals
Phalanges
Box 1. Windlass test and function
a
b
c
Box 2: Anatomy of the plantar foot
and plantar fascia
Plantar
fascia
Lateral
plantar
fascia
Medial
plantar
fascia
Tearing and
inflammation
at the
heel bone
Heel bone
NETWORK WINTER 2019 | 49