The Stance Control Orthosis: Has Its Time Finally Come?
By Judith Philipps Otto
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Bilateral SCOKJ wearer with polio walks in the woods with his dog. Photograph courtesy of Horton's Orthotic Lab. |
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For years, inventive minds have known what
was needed: A free-swinging orthotic joint that allows the knee to
bend and flex under the wearer's control rather than locking it
into a fully extended, stiff-leg position that made ambulation
possiblebut awkward, uncomfortable, and exhausting.
An oft-quoted ten-year-old study claims that approximately
989,000 people wear knee braces. While the same research notes that
an estimated 58 to 79 percent of knee-ankle-foot orthoses (KAFOs)
are abandoned as ineffective by their wearers, authors of a
separate contemporary study also observed that more than 40 percent
of KAFO wearers express dissatisfaction with their orthoses even
though they continue to wear them.
Clearly the stage has long been set, waiting for the arrival of
a talented ingenue to bring salvation and solutions to orthotic
patients clamoring for better performance.
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Bedard |
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Bergmann |
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Clark |
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Horton |
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Michael |
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Smith |
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That star performer appears to be the stance control orthosis
(SCO)and the reviews are unanimously enthusiastic. The SCO recently
opened to an audience eagerly poised to embrace itand in its varied
21st century incarnations, it has yet to disappoint.
For years, inventive minds have known what was needed: A
free-swinging orthotic joint that allows the knee to bend and flex
under the wearer's control rather than locking it into a fully
extended, stiff-leg position that made ambulation possiblebut
awkward, uncomfortable, and exhausting.
Achieving it has been a long-term challenge, however.
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Photograph courtesy of Otto Bock HealthCare. |
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Photograph courtesy of Becker Orthopedic. |
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"Stance control orthoses have come and gone in the 35 years that
I've been around," reflects John Michael, MEd, CPO, FISPO, FAAOP,
an orthotic and prosthetic consultant. "I've seen many through the
'70s, '80s, and '90sand none of them were clinically
successful."
A stance control knee joint design was created in the
Netherlands in 1989 by Nils Van Leerdam, MSc, PhD, at the
University of Twente; the UTX® was introduced in the United
States in 1996 but failed to gain widespread acceptance; likewise,
knee joint technology licensed from NASA by Gary Horton, CO, FAAOP,
was "so complex we could never get it to work. It was too expensive
to follow into manufacture, even if it had worked," Horton
says.
Horton developed his own design, working through several
versions in seven years before introducing in 2000 the landmark
creation officially trademarked as the SCOKJ (Stance Control
Orthotic Knee Joint), popularly referred to as the Horton Stance
Control.
"My goal," says Horton, "was exactly what we gotsomething that
lets your knee bend through swing and locks at any degree of
flexion when you need the safety of it. It blocks flexion but
always allows extension."
The SCOKJ was followed by the Fillauer-distributed SPL (Swing
Phase Lock), Becker Orthopedic's FullStride" and recently released
SafetyStride", and the Otto Bock FreeWalk".
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Photograph courtesy of Horton's Orthotic Lab. |
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In 2003, the mechanical designs were joined by the
first microprocessor-controlled stance control orthosisthe Becker
E-Knee, soon followed by Otto Bock's electronic model, the
SensorWalk". Other electronic models are waiting in the wings, to
debut soon.
Because they use not only their own componentry but also other
stance control knee joints selected by its practitioner customers,
Becker Orthopedic has built more stance control KAFOs than any
other central fabrication facility, says Gary Bedard, CO,
FAAOP.
"Mechanical stance control systems are all gait activated," he
explains. "Some component of the gait process locks and unlocks the
mechanism, whether ankle range of motion, inclination of limb, or
an internal pendulum that matches the limb inclination."
Orthotists choose the appropriate design by matching its
mechanics to the patient's ability, says Bedard. "If the patient
doesn't have ankle range of motion, obviously you can't apply a
mechanical stance control knee joint that's activated by ankle
range of motion."
If a patient has very little hip strength, however,
microprocessor-controlled stance control knee designs compensate
for lost muscle ability.
Other determining factors include cognitive abilities, range of
motion, and triplanar skeletal weight bearing as the patient's
pathomechanics are matched to the abilities of the stance control
componentry.
Keith Smith, CO, LO, FAAOP, Orthotic and Prosthetic Lab Inc.,
St. Louis, Missouri, appreciates the adaptability that stance
control technology offers: It can be used like a standard locked
KAFO, "trading up" to the free-swing feature if and when the
patient progresses. "They get the best of both worlds by doing
that. Patients who have had a KAFO that has been locked for many
years know how hard it is to walktheir back [and] hip hurts. This
offers them a way to get rid of that pain," Smith says.
Who's a Candidate?
"I'm sure there are well over 100 diagnoses for which SCOs have
proved effective," notes Michael. "The problem is it's only a
subset of people with that diagnosis. It's not everyone with a
spinal cord injury (SCI); it's those people with a spinal cord
injury who have a quadriceps weakness or absenceand the ability to
propel the leg forward. Thus I recommend that SCOs be prescribed on
the basis of biomechanicswhat is missing and what can be
restoredrather than the diagnosis."
Kelly Clark, CO, clinical specialist, custom orthotics for Otto
Bock HealthCare, Minneapolis, Minnesota, agrees that diagnosis is
only the starting point for identifying SCO candidate patients.
"You can't say it only works for this diagnosis or that diagnosis.
How does the patient present, and are they appropriate for the
SCO?"
Clark has developed an SCO matrixa useful tool to help
practitioners identify features and capabilities of clinically
available SCO designs (see table 1 ).
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Courtesy of Gary Bedard, CO, FAAOP. |
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Bedard offers another reference: a retrospective
utilization review of UTX stance control systems delivered since
November 2002pigeonholed by diagnosis for which they were ordered
(see table 2).
Kel Bergmann, CPO, has fitted more than 40 patients with a
variety of SCO designs, including an electronic version he
characterizes as "not quite ready for prime time...loud, heavy,
inconsistent," although microprocessor versions are indicated in
cases where patients do not have good muscle strength at the hip,
and lack control of the flexors, extensors, abductors, and
adductors.
"The device's size and weight play a role," he says. "People
with femoral nerve injuries, for examplejust the weight of
something dangling on their leg can create a traction effect that
becomes painful.
"Success depends on what your patient is really going to do with
the device. We've seen some that have come back untouched... The
person took them home and didn't use them at all."
Outcomes Studies
Since SCOs have been clinically available for less than a
decade, there are no long-term studies of any SCO, notes Michael.
Nor are there studies comparing one design to another. The
available research concerning the effectiveness of stance control
orthoses is encouraging, however, and reports are enthusiastic.
The Role of Reimbursement
Every resource contacted for this story cited reimbursement as a
significant stumbling block to the stance control orthosis'
progress and proliferation.
"Reimbursement is certainly one of the major variables that
determine how much stance control technology is used, and how often
it will be considered for a patient," says Keith Smith, CO, LO,
FAAOP, Orthotic and Prosthetic Lab Inc., St. Louis, Missouri.
"Since 1968, orthotic knee joints that unlock for swing phase
have been considered one of the highest priority developments in
rehab. A number of national and international panels have reached
that same conclusion. That makes it all the more tragic," says John
Michael, MEd, CPO, FISPO, FAAOP, "that Medicare went out of their
way to cripple it.
"I don't understand why, but initially they refused to give it a
code. The next year they gave it a code that was patently absurd,
which was a fraction of the cost of the hardware alone. It wasn't
until the third year that they finally gave it a code that was
reasonable, but then they gave an allowable that was very low, so
basically they choked off the technology for three years, and that
is one of the major reasons why it did not take off as rapidly as
it was expected tobecause patients were denied access to it."
Clark points out, however, that the unified front presented to
CMS was a landmark in O&P history. "It was unique that the
manufacturers came together and worked in concert to get a code for
stance control. We all converged on CMS to ensure that the SCO
technology would be available and affordable to patients who could
benefit significantly from it."
Most of the studies used the Horton model or the UTX in
approximately equal numbers. General findings were that range of
motion during swing phase was much closer to normal with whatever
stance control variant had been studied. In every example, the gait
biomechanics compared to a locked knee were significantly improved.
Most patients had a very strong preference for walking in the
stance control mode, noting that it took less effort, or they felt
it took less energy to walk in the SC mode.
"The other finding," Michael notes, "was that almost without
exception, not only did the motion improve in the braced leg, but
the motion of the rest of the body was much closer to normal. So it
had a very positive effect on the opposite leg, on the trunk, on
the head, on the arms, on the whole locomotor apparatus."
A supporting 2006 study found knee motion increasing with less
abnormal pelvic motion.
"That raises the possibility that not only will you walk better,
but that you might have less secondary complications as an elderly
adult if you're not using all these compensations throughout the
rest of your body. I think the results are very supportive and very
positive," Michael says.
Kenton Kaufman, PhD, PE, professor at the Mayo Clinic College of
Medicine, Rochester, Minnesota, summarizes from his own published
studies, and cites others (Amy Gross McMillan, JPO 2004;
Jackie Hebair, PM&R, 2005; and Terris Yakimovich,
Clinical Biomechanics , 2006). "Collectively, these
studies all show improvements in the patients' gait and
improvements in their energy consumption; hence, they tend to do
better overall," Kaufman says.
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Otto Bock's Sensor Walk |
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Kaufman's 2006 study on consumer opinion showed
that the weight and the bulk of a SC knee joint will be acceptable,
so long as the functional benefits; i.e., the improved gait, are
significant to the patient.
"Many people had previously decided that their locked brace was
too restrictive and too cumbersome for them; that's why physicians
basically stopped prescribing thembecause patients weren't using
them," Kaufman says. "I think now, with this new SCO technology,
people can actually use them and be functional and not be
restricted in their mobility.
"I think it's important for the practitioner to know that if
they see a patient who has used a locked brace, initially the
patient may not have as much confidence in their SCO as they had in
their locked braceessentially, they have to relearn how to walk
with the SCO. A new user who hasn't been habituated to a locked
knee will tend to do better initially."
Michael agrees. "It was very clear that the locked KAFO wearers
took much longer to adapt to the SC gait than did the novices who
received a stance control device," he says. "The prior wearers
walked slower, they walked at a lower cadence, and it took six
months or longer before they really began to show the
benefits".
"Previous wearers have the habit of security; you can't get any
more stable than with your knee locked all the time," points out
Horton. "Novice wearers accept it better in training because they
don't have old habits to break."
Through patient feedback, Horton discovered an added benefit.
"Patients really like...being able to walk with the knee bending,
which gives them a more normal gait and look, without attracting
attention to a limp. There's no real physical benefit from that,
but it's a great mental benefit."
Are SCOs Underutilized?
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Photograph courtesy of Horton's Orthotic Lab. |
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Just as every source contacted for this story
cited reimbursement as a significant stumbling block to the
advancement of stance control technology, they also agreed that as
a result the technology is not being utilized as it couldand
perhaps shouldbe.
Kaufman points out that the strong need and desire of KAFO
wearers for a better orthotic solution was dramatically illustrated
by the influx of hopeful phone calls from the public, responding to
a non-specific mention in a newsletter of the knee brace study in
progress.
"They had to really swim upstream to find us," says Kaufman.
"Yet we got numerous calls from literally all over the United
States and South America."
However, in the face of this eager demand, Bedard notes that in
an audience of 500 people at the 2007 Annual Meeting and Scientific
Symposium of the American Academy of Orthotists and Prosthetists
(the Academy), only 30 percent had any experience in providing
SCOs; only 15 percent had fitted as many as five; and only two
people had fitted ten or more.
Clark's informal polls have gleaned similar findingsshowing that
only 5 to 10 percent of his audiences have fit any SC orthosis,
regardless of brand.
"Everybody loves the concept," Clark concludes. "But in
practice, I wouldn't say it's been well accepted. We estimate that
between 1,200 and 1,600 of these go out a year, extrapolating from
Medicare usage figures. Compared with the population of KAFO
wearers, that would be way under-prescribed or underutilized."
Why so Few?
"The stance control orthosis is...much more like a prosthesis in
that you really need an in-depth evaluation of how the way the
patient walks affects the way the joints work," Michael points out.
"You need to have them engage and release at the right time in the
gait cycle, and there needs to be follow up to maintain the
adjustment and the fitting and so on. So it is in many ways a more
complex interaction than the traditional KAFOrequiring a greater
time investment from a more serious and dedicated orthotist.
"You don't have to be a genius," Michael continues. "But you
really need to be serious about being an orthotist because there is
a time commitment in the evaluation, in the fabrication, in the
fitting, and in the follow up. And that is one of the primary
barriers to more widespread use."
Smith agrees. "It requires not only a very involved
orthotist...but they're going to need a physical therapist that
knows the technology to work with this patient, instructing them
and teaching them how to use the brace....
"For eight months I require that the stance control KAFO patient
gets physical therapy, and I talk to the PT before we actually go
after fabricating the brace for the patient. You've got to educate
the therapist in the use of these and how they work."
Kaufman believes that after five years in the marketplace the
SCO concept is at last capturing the interest of more
practitioners, and given the standing-room-only crowd at his SCO
symposium at the August 2007 International Society for Prosthetics
and Orthotics (ISPO) meeting, he is no doubt on to something.
Judith Philipps Otto is a freelance writer who has assisted
with marketing and public relations for various clients in the
O&P profession. She has been a newspaper writer and editor and
has won national and international awards as a broadcast
writer-producer.
Editor's note: The O&P EDGE does not endorse
any particular product or service. Product information provided in
this article is for reader information only.
Miracles in the Making
The SCO has offered unexpected advantages for the open
minded:
Reduced Rehab Time
"Gary Horton has discovered that his SCO knee joint appears to
cut rehab time in half for people who have had multiple total knee
replacements, and have hence experienced weakened quadriceps
function," reports John Michael, MEd, CPO, FISPO, FAAOP. "Their
return to work time is cut to one tenth of what it would have been
with traditional therapy. The SCO acts as a strengthening device as
well as a protective deviceand it's also ten times cheaper.
Return of Function
"We are also seeing a lot of anecdotal reports of spontaneous
return of function in the people with spinal cord injury," says
Michael. "In case after case, people were told they have a
permanent disability, they will never walk again, they need to lock
their leg in a brace.... When they went into the Horton's variant,
because that particular one allows you to use residual quadriceps
function, within 12 to 24 months they were able to walk without the
KAFO. Now, none of this has been scientifically studied, but once
we see dozens of apocryphal reports like that, we begin to think
that there really is something to it."
Stance Control Plus FES
"There have also been some research experiments combining the
Horton's stance control KAFOs bilaterally along with functional
electrical stimulation (FES) for a person with complete spinal cord
trans-section at a very high level," notes Michael. "He is unable
to stand unaided, but with the electrical stimulation of his
remaining muscles and with bilateral KAFOs, he is able to walk for
short distances with the walkerso that has potential research
value."
SCOKJs Plus RGOs
Working with a T-10 level spinal cord injury patient, Smith
reported that combining a bilateral SCOKJ with a reciprocating gait
orthosis (RGO) enabled the patient to walk faster, more naturally,
and more efficiently in the stance control mode, with less upper
body compensations (JPO 2007, vol 19, number two, pp. 4247,
Aaron Rasmussen, Keith Smith, and Diane Damiano). Additional
SCI patients are also being studied, with similar results: more
controlled walking, less energy expenditure, all parameters
increased and improved. As Smith notes, "Pretty exciting
stuff."
Table Of Contents - March 2008
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