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discrepancy provide protection, but do little to correct the equinovarus deformity. More functional devices
often require a contralateral shoe lift to correct the length discrepancy.

At our institution, a carbon fiber AFO with an insert or the Phat Brace style orthosis (Bio-mechanical
Composites, Des Moines, IA, USA) is commonly employed to provide improved third phase of gait and
generate equal step lengths.

Syme amputation
[28]
The Syme amputation, first described by Scottish surgeon James Syme in 1843 , is synonymous with
an ankle disarticulation procedure for the treatment of various foot pathologies not amenable to a more
distal resection. This amputation is also frequently performed in children with congenital foot deformities.
Transection proceeds through the ankle joint and includes the medial and lateral malleoli to achieve an
even articular surface. The proximal heel pad is used for coverage. This level of amputation is advantageous
as compared to a transtibial amputation as it provides superior gait stability and decreased energy
expenditure [29,30] . It also provides a greater lever arm length as compared to a more proximal amputation.
Postoperative rigid casting allows for partial weight bearing almost immediately post-procedure and early
fitting with a prosthesis is often possible. Patients require less physical therapy gait training than with
[31]
transtibial amputation . The retained plantar tissue provides a durable weight-bearing surface and end-
limb proprioception remains intact. The residual limb allows for end-bearing so that short distances may be
walked without a prosthesis. In patients for whom cognitive or other health factors might preclude prosthesis
use, end-bearing can be functionally useful for transfers or standing ADLs. The principle is also true for
Chopart and Lisfranc amputations.

Prosthesis and orthosis for Syme amputations
There are several prosthetic considerations unique to a Syme amputation. The socket of the prosthesis must
conform to a bulbous distal residual limb and therefore can be bulky. Generally speaking, two primary
types of prosthetic options are available: closed or windowed. Closed prostheses have a “stove-pipe” external
appearance as they make use of the residual ankle contour to suspend the prosthesis. Windowed variations
allow for a more natural external ankle contour, but must be closed with Velcro straps [Figure 2]. The
articulation of the residual limb and adaptive prosthetic foot distally is subject to significant stress. This
force must be accounted for and subsequently offloaded by the prosthetic foot. Until recently, sophisticated
foot componentry was limited for this level amputation. However, a number of prosthetic manufacturers
now provide carbon fiber, energy-storing Syme prosthetic feet. It should be noted that a Syme amputation
will almost always lead to a limb length discrepancy as the prosthetic foot must be placed under the residual
heel. Therefore, orthosis in the contralateral footwear is needed to correct the limb length discrepancy.

Transtibial amputation
A transtibial, or below-knee amputation (BKA), is the most common level of amputation. The vast majority
[32]
of patients undergoing a transtibial amputation will heal their amputation site without complication .
Patients undergoing a below-knee amputation have a much greater likelihood of ambulating with a
prosthesis compared to above-knee amputees, owing to both the mechanical advantages of preserving the
knee joint and underlying patient factors predisposing the level of amputation (i.e., often these patients will
have greater functional reserve compared to those undergoing above knee amputations). It should be noted,
however, that there are situations in which below the knee amputation may not be better than a higher level
amputation. For instance, a BKA can predispose to flexion contracture of the knee particularly in patients
who are non-ambulatory. Knee flexion contractures can predispose to development of pressure ulcers on the
distal residual limb from lying in bed. Patients with spasticity and pre-existing flexion contractures may not
be appropriate for BKA, as this may exacerbate the contracture.

The primary surgical consideration of a transtibial amputation relates to the precise anatomic level of
bony transection. The ideal length of the residual limb is between 12.5 and 17.5 cm measured from the