According to data from the Vital and Health Statistics, Ambulatory and
Inpatient Procedures, and accounting for the increase in population since 1996,
it is estimated that 1.27 million Americans live with lower-limb amputation. Of
those 1.27 million, more than 618,000 have partial foot amputations.
Partial foot amputation is most commonly caused by advanced
vascular disease and diabetes. Approximately 76% of cases, involve the
amputation of the toes. Transmetatarsal or mid-tarsal amputations, account for
approximately 24%.
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| Stefania Fatone |
For patients with systemic illnesses, partial foot amputation is often
the first component in the long processes that, for many, result in skin
breakdown and secondary amputations, potentially leading to transtibial
amputation, according to
Michael P. Dillon, BP&O (Hons.), PhD, lecturer and first year
coordinator, National Centre for Prosthetics and Orthotics, LaTrobe University.
The study, Biomechanics of Ambulation after Partial Foot
Amputation: A Systematic Literature Review, revealed that understanding
on the subject is limited due to a lack of data.
“Based on the outcome of the systematic review, it is clear that
our understanding of the biomechanics of gait following partial foot amputation
lacks depth,” the authors wrote in the literature review. “There
exists a high level of evidence only for broad observations in a few aspects of
gait, such as ‘partial foot amputation has an affect on kinematics,’
with limited evidence to support a more detailed understanding of how partial
foot amputation affects ankle kinematics.”
Stefania Fatone, PhD, research assistant professor, prosthetics and
orthotics center, Northwestern University, explained that until recently, the
onlyknowledge available to clinicians was based on their experiences and
clinical intuition. However, more data has slowly emerged, potentially helping
practitioners better educate their partial foot amputee patients. Patient
education is crucial in order to combat the high rates of secondary amputation
and skin breakdown associated with partial foot amputation due to conditions
such as diabetes, she said.
“From what we have learned over the last couple of years, it is not
necessarily difficult to restore ambulation, it is just difficult to do it in a
way that the patient accepts,” Fatone explained to O&P Business
News. “What our research and work has shown, is that in order to
restore the biomechanics of walking for the partial foot amputee who has lost
the metatarsal heads, patients must wear a device that extends above the
ankle.”
The only way the center of pressure progresses along the foot and
restores the body’s ability to load the foot for walking is to wear a
device that extends above the ankle. However, to the patient, wearing a large
orthotic device despite losing only part of their foot may not make sense nor
may it be pleasing to the eye.
“The problem is, as practitioners, it is difficult to restore the
biomechanics of ambulation in a person who has lost the metatarsal heads with
any device that stays below the ankle and yet that is the device that a partial
foot amputee might prefer,” Fatone explained. “That is kind of the
conundrum we are in right now.”
How do you solve that conundrum? One way is to accumulate more data for
the patient.
“The reality is that because the evidence we have is somewhat
limited, we cannot make definitive statements about who would particularly
benefit from the various devices,” Fatone admitted.
Another issue for practitioners is that restoring the biomechanics of
gait may not be the only goal of treatment.
“Restoring ambulation is only one of the many goals,” Fatone
said. “Many partial foot amputees have undergone amputations because of
systemic illnesses such as diabetes or vascular disease. Protecting their
residual limb may be a bigger goal than restoring ambulation.”
Fatone recommended providing a patient with multiple devices or a device
that is above the ankle in order to restore the biomechanics of walking, but
also separates so the patient can wear the below-ankle component for cosmetic
purposes.
“If a partial foot amputee is not routinely walking in the
community due to additional co-morbidities associated with their diabetes,
restoring the biomechanics of their gait may not be a top priority,”
Dillon explained to O&P Business News. “As opposed to a person
who wants to maintain an active lifestyle would have extra incentive to improve
their biomechanics.” — by Anthony Calabro
For more information:
Dillon MP, Fatone S. Evidence Note: The Biomechanics of Ambulation
after Partial Foot Amputation. Washington D.C. American Academy of Orthotists
and Prosthetists. 2009.Dillon MP, Fatone S, Hodge MC. Biomechanics of ambulation after
partial foot amputation: a systematic literature review. The Journal of
Prosthetics and Orthotics. 2007; 19:2-61.Owings M, Kozak L. Ambulatory and inpatient procedures in the
United States, 1996. Vital Health Statistics 13. 1998;13:1-119
Dr. Fatone comments: “… in order to restore the biomechanics
of walking for the partial foot amputee (who has lost the metatarsal heads)
patients must wear a device that is above the ankle.” The accuracy of this
statement is becoming clearer as we deal with more partial foot amputees.
I have been involved with a pilot study to validate the use of dynamic
carbon AFOs in conjunction with a socket-type custom foot orthotic. The initial
indications are that an AFO with a full foot plate, custom orthotic and toe
filler provides many benefits. The foot plate restricts excessive flexion of
the shoe and prevents the bending of the filler onto the residuum. It also
appears to limit plantarflexion of the residual foot reducing peak plantar
pressure and shearing forces. In addition, the AFO allows the transfer of
energy to the upright which can then be returned for the propulsive phase of
gait.
To date, there is a lack of clinical evidence to support these
assumptions. This is due, in part, to the fact that this patient population is
notoriously noncompliant and their disease process often progresses rapidly.
However, it benefits all of us to continue gathering data and documenting the
very best practices to heal and protect our patients.
— Seamus Kennedy, Beng (Mech), CPed
Owner,
Hersco Ortho LabsPresident & chief executive officer, Amputee Coalition of
America
