suggestions from the field Four-Bar Gait-Control Linkage
suggestions from the field
Four-Bar Gait-Control Linkage
RHONDA L. DAVID, BS,
and RAYMOND H. ROLFES
The patient was a 61-year-old black man with a
history of chronic alcoholism, peripheral neuropathy,
difficulty in walking, and urinary retention. He was
diagnosed as having spastic paraplegia with modified
Brown-Séquard syndrome at T3. He underwent a
laminectomy between C6 and T3 in March 1979
because of a spinous tumor.
When the patient was evaluated for lower extremity
bracing in May 1979, he had isolated motor control
in both lower extremities. But severe spasticity in the
muscles that flex, adduct, and internally rotate the
hip and flex the knee prevented specific manual
muscle testing. He needed a knee-ankle-foot orthosis
to walk because of buckling at the knees and severe
lower extremity scissoring. When the spasticity was
inhibited, strength was generally Poor to Fair in the
hip musculature, Good in the quadriceps femoris
muscles, Poor in the hamstring muscles, and Poor to
Fair in the ankle musculature. The patient's upper
extremity strength was Good and trunk strength was
Fair. Range of motion was within normal limits
except for hip extension (minus 10 degrees).
The patient was unable to control severe hip adduction in the upright position with bilateral kneeankle-foot orthoses. Instead of using a conventional
spreader bar, we constructed a device called the fourbar gait-control linkage* on the orthoses to control
the severe scissoring and to allow reciprocal gait (Fig.
Fig. 1. Close-up of four-bar gait-control linkage.
Materials and Design
Two aluminum bars ¾ inf wide, ¼ in thick, and 6 in
Two stainless steel bars ¾ in wide, ⅛ in thick, and 4
Three thrust-bearing joints.
Four truss-head screws10/24in wide by3/8in long.
The two aluminum bars are joined together with a
thrust bearing at the distal end, and the other two
ends are joined to the stainless steel bars with the
same thrust bearings. The two proximal joints are
† 1 in = 2.54 cm.
* Patentability of this device is being investigated.
Ms. David was Senior Therapist, Department of Physical Therapy,
Fairmont Hospital, San Leandro, CA, when the article was written.
She is currently Senior Therapist, Department of Physical Therapy,
Santa Clara Valley Medical Center, San Jose, CA 95128 (USA).
Mr. Rolfes is a certified orthotist at Hayward Orthopedic Co, Inc,
22257 Mission Blvd, Hayward, CA 94541.
Address correspondence to Ms. David, 100 Jordan Ave, Los Altos,
This article was submitted December 12,1980, and accepted January
Fig. 2. Four-bar gait-control linkage attached to orthoses.
placed 3 in above the knee joints of the knee-anklefoot orthoses and attached with the stainless steel bars
to the medial upper upright of the knee-ankle-foot
orthoses with two each truss-head screws (Fig. 2).
Proper alignment of all joints is necessary to permit
unimpeded swing-through during ambulation and to
permit confortable sitting.
At discharge, with this device, the patient was able
to walk with bilateral axillary crutches independently
on all surfaces with a reciprocal four-point gait. He
was able to negotiate 4-in stairs using a typical paraplegic swing-through gait.
Splint for Infant with Myelomeningocele
D. LaVONNE JAEGER, MA
The ability of the child with myelomeningocele to
stand or walk is often compromised by hip flexion
contractures. If this problem is to be avoided, preventive measures must be undertaken early, ideally in
the neonatal period.
The normal neonate lies in the fetal position with
the lower extremities flexed. The constant force of
gravity gradually pulls them into extension. The infant with myelomeningocele often has insufficient
adductor control to prevent the lower extremities
from falling into complete abduction when they are
flexed. This abduction in the flexed position may be
so extreme the legs lie flat on the bed in what is often
termed a "frog leg position." When the legs are in
this position, gravity cannot pull them into extension.
In addition, if the lesion is below L1 and above S2,
there will be no hip extensor motion to counteract the
hip flexor muscles. If the lesion is above L1, the hip
flexors, under spinal cord control, may function excessively in the flexor-withdrawal reflex.
In order to counteract the tendency toward hip
flexion, we designed a splint* to meet the following
criteria: 1) be inexpensive, 2) be washable, 3) would
position the lower extremities so gravity would pull
them into extension but would not force them into
extension, 4) would not produce pressure areas on
desensitized skin, and 5) would maintain the lower
extremities in the optimum position for integrity of
the hip joint. The studies of McKibbon have shown
that there are two options for optimum hip positioning in the newborn: flexion-abduction-external rotation or extension-abduction-internal rotation.1, 2 The
* Splint (Patent no. 4,135,504) now available from Span-America,
Inc, Box 5231, Greenville, SC 29606.
Ms. Jaeger is Associate Professor, Physical Therapy Department,
University of Kentucky, Lexington, KY 40536 (USA).
This article was submitted February 1, 1980, and accepted October
Volume 61 / Number 6, June 1981
Figs. 1,2. The straps are wrapped around the leg and
attached to the ventral surface with Velcro, pulling the
legs into internal rotation.
latter is the position of choice when the tendency
toward hip flexion contractures is present.
The splint can be purchased or easily fabricated.
The material used for the pad and strap should be
firm, with a sponge-like consistency to decrease the
possibility of any pressure sores. The pad and strap
are cut to the following measurements:
Splint for Neonate:
Pad: 2 in† thick, 4 in long, 2 in wide, tapering to 3.5
† 1 in = 2.54 cm.