Energy Storing Orthosis May Be an Alternative to Amputation After Limb Salvage

Patients who have had limbs salvaged after traumatic injuries often
struggle to regain full functionality of the limb due to muscle loss, chronic
pain and nerve damage. While amputation and prostheses are alternatives to limb
salvage, not much is known about how orthoses can affect limb salvage outcomes.

Researchers from the San Antonio Military Medical Center at Fort Sam in
Houston recently studied the effects of orthoses on limbs salvaged after
high-energy lower extremity trauma.

“To our knowledge, no study to date has investigated the use of
energy-storing orthoses in a population that underwent limb salvage following a
traumatic injury,” the authors wrote in the study, which was published in
the Journal of Bone Joint and Surgery. “Furthermore, the
effectiveness of these orthoses compared with that of other commercially
available options has not been adequately studied.”

The researchers chose 18 active duty males, between the ages of 18 years
and 49 years who had unilateral dorsiflexion and/or plantar flexion weakness.
They had all undergone the Return to Run clinical pathway, a multidisciplinary
treatment plan for military personnel that is unique to the San Antonio
Military Medical Center. The program incorporates orthopedic surgery, physical
therapy, prosthetics and orthotics, physical medicine and rehabilitation,
mental health and pain management. Patients are also offered the use of the
Intrepid Dynamic Exoskeletal Orthosis (IDEO), a custom carbon fiber,
energy-storing ankle-foot orthosis.

The IDEO incorporates a posteriorly mounted carbon fiber strut with a
proximal ground-reaction cuff and a distal supramalleolar AFO. The cushioned
heel enables shock absorption during the loading phase. The plantar flexed
position of the foot plate, which is inspired by prosthetic running feet,

Each participant performed five functional measurement tests: the
four-square step test, sit-to-stand five times test, timed stair ascent,
self-selected walk velocity over level terrain and self-selected walking
velocity over rocky terrain. Each test was performed five times under each of
the four bracing conditions. The participants also completed one 40-yard dash
for each bracing condition.

The researchers found that the IDEO significantly improved functional
performance compared with all orthotic conditions for all of the measures, with
the exception of the sit-to-stand five times test.

“This is not surprising given that the test relies more on power at
the quadriceps and core musculature than power at the ankle,” the authors
wrote. “Of note, use of the IDEO allowed patients to perform the
four-square step test and self-selected walking velocity test on both level and
rocky terrain at the same speed as was achieved by the healthy, uninjured
control subjects reported [in previous studies].”

The biggest functional improvement occurred while wearing the IDEO
during the 40-yard dash. There was a 4.9-second improvement over no orthosis,
4.3-second improvement over the posterior leaf spring and a 3.4-second
improvement over the BlueRocker.

There was no significant difference in performance for the functional
tests between the BlueRocker, posterior leaf spring and no orthosis. The IDEO
was also reported to be the most comfortable and durable orthosis, as well as
the most cosmetically appealing option.

In addition to the tests, participants also completed a satisfaction
questionnaire and indicated whether they had ever considered having an
amputation, and if so, whether they still intended to proceed with it.
Initially, 13 patients considered amputation, but after completion of the
trial, eight desired limb salvage, two were undecided and three still wanted an

Future studies

The researchers acknowledged several limitations to the study, including
the small study size and the absence of long-term follow-up data. Another
concern is how a civilian population that did not complete the Return to Run
clinical pathway would perform on these tests.

“Our active duty population lacks external validity when compared
with a civilian population treated with limb salvage following traumatic
injury,” the authors wrote. “The Return to Run clinical pathway is
unique to our institution. Although we believe that the multidisciplinary
approach is an important factor in our patients’ improvements, further
study is required to prove this.

“A formal biomechanical analysis is currently under way at our
institution to fully characterize the effect of the device on ankle power,
motion and work,” the authors added. — by Megan Gilbride

For more information:

Patzkowski JC, Blanck RV, Owens JG, Wilken JM, et. al. Comparative
effect of orthosis design on functional performance. J Bone Joint Surg Am.

Disclosure: One or more of the authors received payments or services,
either directly or indirectly, from a third party in support of an aspect of
this work. In addition, one or more of the authors, or his or her institution,
has had a financial relationship with an entity in the biomedical arena that
could be perceived to influence or have the potential to influence what is
written in this work.

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