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July 2005 • Vol. 1, No. 2
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Advancing Orthotic and Prosthetic
Care Through Knowledge
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by Keith M. Smith, CO, LO
Traditional hip orthoses implemented to stretch the adductor
group of tendons have evolved over the years as static positioning
orthoses with the goal being an abducted position of
the hip. Majestro and Frost pointed out that structural or bony
deformities arise from abnormal muscle forces and that correcting
these abnormal forces early in life could prevent or alter
these structural deformities while the child is growing (1). Petri
casts are used in postoperative situations and in some cases as
a serial casting method of increasing the adductor length, typically
post-Botox injections. Orthoses are more prevalent due
to ease of removal for bathing and exercising.
Beals pointed out that preambulatory
orthoses may be beneficial to acetabular
development (2). Other studies concur
with this ability of the acetabulum to develop
a more stable socket for the femur if
the head is well positioned (3, 4). Scrutton
took a retrospective look at the literature
and found a common conclusion to be
that these hips in cerebral palsy patients
are normal at birth (5). Kalen and Bleck
emphasize the importance of preventing hip deformities in the
CP patient due to resultant pain, postural difficulty, interference
with ambulation, and problems with perineal hygiene (4).
Knapp and Cortes pointed out that it is the adductor tightness
that prevents this perineal care (6).
Two problems with this patient population are compliancy
from parents and caretakers due to difficulty in donning the
orthosis on a child with spasticity and/or contracture in these
abducted positions, and internal rotation resulting from strain
or tension when abducting the legs. In their review, Aminian
et al. recognized that internal rotation, among other factors,
could come from over-activity of the internal rotators of the
hip, medial hamstrings, and the adductors (7).
The design that we sought was one that would allow the
patient’s parents or caretakers to don the orthosis with the
child’s legs in the adducted position and then click a release
that would position the legs in abduction. The idea was to
implement a design that would greatly improve the caretaker’s
ease in donning the orthosis, eliminating the need to abduct the
legs manually. Our goals remained unchanged from current A-Frames
being to prevent or delay surgery, to decrease scissoring in gait by stretching the adductors and internal rotators, and to attempt to seat the head of the femur in the acetabulum of the
hip.
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Figure 1. Original design
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An orthosis was fabricated in much the same manner as an A-Frame
in which custom-molded knee orthoses were fabricated.
The orthosis ran from just proximal to the ankle up to just distal
to the perineum medially and just distal to the trocanter laterally.
The knee was secured with a padded
cage over the knee to give a third point of
pressure to keep the orthosis in position. At
the initial fitting, a second and third strap
were added to the thigh and lower calf to
help keep the orthosis from migrating.
The abduction joint was added along with
a strap between the legs at the most proximal
end to connect the two knee orthoses
and to create a pivot to enhance abduction
(Figure 1). Dynamic joints were also used
at the knee to increase range of motion to the hamstrings. The
dynamic abduction and extension joints were fabricated by
Ultraflex Systems Inc., Downingtown, Pennsylvania, and further
adaptations were developed by the author in conjunction
with Ultraflex Systems.
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Figure 2. Feet incorporated and rotational control
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Figure 3. Rotational control by the practitioner
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Our patient tolerated the orthosis well and his father was
pleased with the ease of donning. Clinically, the picture was
similar to the A-Frame, except for greater donning/doffing ease
and the ability of the patient to adduct against tension with a
reflex and then abduct when relaxed. The scenario gave us the
first dynamic hip abduction orthosis for stretching and met our
goals. It was evident, however, as it is in casting as well as the
A-Frame, that the legs were internally rotating. We changed
the knee orthosis to knee ankle foot orthosis (KAFO) to be
able to grab the ankle and foot and help control this internal
rotation (Figure 2). Later an adaptation was added that allowed
for adjustability in the transverse plane to increase or decrease
this rotation angle (Figure 3). To the author’s knowledge, this
is the first component used specifically to statically allow the practitioner varying degrees of rotational
control in the transverse plane.
The patient was instructed to wear the
orthosis every night to bed and if possible
for an hour during the day. In consideration
of the proximal hamstring stretching,
another adaptation was added that allowed
the parent to quickly disconnect the KAFOs
from the entire abduction mechanism to
allow the patient to do a proper stretch of
the proximal hamstrings (Figure 4). To
get this stretch without the orthosis on, a
caretaker must hold the contralateral leg
down while at the same time flexing the hip
and extending the knee on the ipsilateral.
The majority of patients feel overwhelmed,
like they need a third hand. With this new
adaptation, all a caretaker has to do is
disconnect the mechanism and hold one
leg down while lifting the other (Figure
5). The KAFO keeps the knee extended,
serving as a third hand.
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Figure 4. Quick disconnect
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Figure 5. Quick disconnect allows for proximal hamstring stretch
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Our patient has been wearing the
orthosis for approximately six months
and has gone from an abduction range
of approximately 20 degrees bilaterally
from the mid-sagittal line to 40 degrees
bilaterally. Clinically, the patient now
ambulates with a decreased amount of
scissoring, which has greatly improved
the cadence in his gait pattern. Wearing
time, initially every night and one hour
during the day, has fallen to every other
night and one to two hours every day. The
author emphasizes the nighttime wear, but
in situations where that is unachievable,
then one or two hours of wear during the
day becomes more crucial. Caretakers
are pleased with the ease of donning and
the ability to adduct against the joints has
created a more comfortable method for
stretching.
Our initial goal of creating an orthosis that achieves the abduction
position and limitation of internal rotation that current A-Frames
accomplish and to make it drastically easier for parents
to don the orthosis has been met. The purpose of this design
was not to change current thought, but rather to design a system
that would allow the caretaker to don the orthosis with the
patient’s legs in the adducted position and allow the dynamic
joints to do the abduction. The extra adaptations of rotation
control and the quick disconnect feature
have enabled us to take treatment a step
further functionally for hip position and
practically by allowing the orthosis to be
used as an assistant when doing proximal
hamstring stretching.
Our question now becomes, “Can we
ultimately change the natural history of hip
adductor tightness and resultant structural
changes in the cerebral palsy population
by abducting the legs and preventing
internal rotation while doing so?” And
second, “Can it be effective in changing
a patient’s gait pattern to allow for a more
efficient stance and swing position of the
legs in relation to each other?” The author
has fit 12 additional patients with this new
design and is seeking to investigate these
questions. We also hope to determine if
improvement upon the static position of
A-Frames has indeed been met with a
dynamic system, and if there has been
orthopedic improvement to the anatomy
of the hip in the cerebral palsy patient. The
author proposes to look at radiographs
in and out of the orthosis to determine
efficacy, as well as in different positions of
internal and external rotation to determine
the role of the orthosis in hip stability.
Majestro TC, Frost HM. Cerebral Palsy
Spastic Internal Femoral Torsion. Clin Orthop
Rel Res 1971;79:44-56. Beals RK. Developmental Changes in the
Femur and Acetabulum in Spastic Paraplegia
and Diplegia. Dev Med Child Neur
1969;11:303-13. Harris NH, Lloyd-Roberts GC,
Gallien R. Acetabular Development in
Congenital Dislocation of the Hip with
Special Reference to the Indications for
Acetabuloplasty and Pelvic or Femoral Realignment
Osteotomy. J Bone Joint Surg Br
1975;57B:46-52. Kalen V, Bleck EE. Prevention of
Spastic Paraplegic Dislocation of the Hip. Dev Med Child Neur
1985;27:17-24. Scrutton D. Review Article: The Early Management of Hips in
Cerebral Palsy. Dev Med Child Neur 1989;31:108-16. Knapp DR, Cortes H. Untreated Hip Dislocation in Cerebral
Palsy. J Ped Orthop 2002;22:668-71. Aminian A, Vankoski SJ, Dias L, Novak RA. Spastic Hemiplegic
Cerebral Palsy and the Femoral Derotation Osteotomy: Effect
at the Pelvis and Hip in the Transverse Plane During Gait. J Ped
Orthop 2003;23:314-20.
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