A New Approach to Patient Analysis for Orthotic Prescription- Part I: The Lower Extremity
Newton C. Mccollough III. M.D. *
Charles M. Fryer. MA. *
John Glancy, CO. *
There is little question that the field
of orthotics has taken a back seat to prosthetics in modern times, and perhaps
for good reason. The needs of the amputee are more immediate and obvious, and
the wars of the past thirty years have yielded untold numbers of young men in
their prime whose productivity depended upon satisfactory functional restoration
of their missing limbs. Medicine, engineering, and the prosthetic profession
have responded to the needs of the amputee through extensive research and
development, widespread educational programs, improved fabrication and fitting
techniques, and better delivery of services. The field of orthotics remains in
comparative disarray with more limited, though no less sophisticated, research
activities, few educational endeavors, and little improvement upon local
fabrication and delivery services over the past fifty years.
Much of the blame for this rather
distressing state of affairs must be laid to the physician, whose approach to
orthotic prescription has been somewhat less than scientific. More often than
not, little thought is given to analyzing specific biomechanical defects present in an
extremity with the aim of translating them into an appropriate mechanical
substitute. Even when this is done, all too often the device that is prescribed
impairs to some degree the normal biomechanical functions which coexist in the
same extremity. For example, a long leg brace prescribed for genu recurvatum may
also limit normal functioning of the subtalar joint. Much of the physician's
casual approach to orthotic prescription stems from a relatively sparse
education in orthotic principles, but an even greater deficiency is the failure
to relate well-known biomechanical principles to the mechanical substitute, or
orthosis. Therein lies the trap, for without this awareness, prescriptions will
continue to reach the orthotist calling for simply a "short leg brace" or a
"long leg brace," and thus there is no stimulation for new or improved design
criteria for orthotic components and systems.
There is little doubt that the great
advances which have been made in prosthetics in recent years have resulted
primarily from a systematic appraisal of normal human posture and locomotion,
with resultant attempts to duplicate not only the missing anatomy but also the
biomechanical functions of the extremity. The problem in orthotics is somewhat
different: specific functional losses must be substituted for in the presence of
intact anatomy, and the variety of functional losses which may be present in a
given extremity necessitates correspondingly varied design criteria. It is apparent,
therefore, that an initial step in developing a rational approach to orthotic
design and prescription would be some means of systematically analyzing the
biomechani-cal losses in an impaired extremity. Once properly identified, these
losses could then be matched against specific components or component systems to
substitute for the functions lost. In addition, such an analysis might point up
certain areas or functions for which truly satisfactory components are not
available, and thus it might serve as a stimulus for future design and
development.
Recognizing the need for a more organized
and systematic approach to orthotic prescription as a part of current efforts to
revise volume 1 of the Orthopaedic Appliances Atlas, the Committee on
Orthotics and Prosthetics of the American Academy of Orthopaedic Surgeons
appointed an ad hoc committee for the development of a lower-extremity analysis
form. In essence, this article represents a report of that committee, whose work
commenced two years ago. During the development of the form, workshops were held
periodically with the parent committee, together with representatives of the
American Orthotic and Prosthetic Association, the Veterans Administration
Prosthetics Center, and the Committee on Prosthetics Research and Development of
the National Research Council. The form underwent periodic revision as it was
applied to patients with a variety of disabilities, utilizing several clinics.
The most recent and final application of the lower-extremity analysis form was
in conjunction with the Workshop Panel on Lower-Extremity Orthotics held at
Rancho Los Amigos Hospital in Downey, California, in March 1970. Its
applicability to the evaluation of lower-extremity disability is now felt to be
such as to warrant description for more widespread usage.
Lower-Extremity Analysis Form
The form consists of four pages of
appropriate size for insertion into the patient's hospital chart. The first page
Fig. 1 contains spaces for patient data, including the diagnosis and a summary
of major impairments existing in one or both extremities. At the bottom of the
first page there is a legend for symbols to be used on the extremity diagrams.
The second and third pages Fig. 2,Fig. 3 contain skeletal outlines of the right and left lower extremities, respectively, in the sagittal, coronal, and
transverse planes. Overlying the major joints are shaded areas, representing the
normal ranges of joint motion within a circle divided into thirty-degree
segments. Similar smaller circles overlie the mid-shafts of the long bones for
diagraming angular, rotational, or translational deformities of the femur and
tibia. The fourth page Fig. 4 includes spaces for summarizing the functional
disability, and for orthotic recommendations based upon this summary.
Instructions for Use
Most of the "Major Impairments" portion
of the form is self-explanatory. "Abnormal bone and joint" conditions may
include such entities as osteoporosis, Paget's disease, and coxa vara. "Muscle"
may be normal, flaccid, or spastic, but a space is provided for description of
rarer disorders such as muscular dystrophy and fibrosis of muscle. Under the
heading of "ligament," check boxes are provided to indicate abnormal laxity of
the major ligaments of the knee and ankle. The sections on "sensation," "skin,"
and "vascular" impairments cover considerations which may influence orthotic
design, and are self-explanatory.
"Balance" is either normal or impaired,
and if impaired, the following definitions are applicable: "mild" impairment is
compatible with independent ambulation; "moderate" impairment is compatible with
ambulation utilizing external support; and "severe" impairment indicates the
need for maximal support or personal assistance in ambulation.
"Extremity shortening" is recorded as
follows: ischial tuberosity to sole of heel, ischial tuberosity to medial tibial
plateau, and medial tibial plateau to sole of heel.
In leg-length discrepancies exceeding
one-half inch, X-ray studies of leg length may be indicated, and an appropriate
space is provided for this measurement.
Legend and Extremity
Diagrams
Two terms must first be
defined:
- "Translatory motion" is
motion in which all points of the distal segment move in the same direction,
with the paths of all points being exactly alike in shape and distance traversed
Fig. 5.
- "Rotary motion" is motion
of a distal segment in which one point in the distal segment or in its
(imaginary) extension always remains fixed Fig. 6.
The symbols described in the legend are
used in conjunction with the right-and left-extremity diagrams according to the
following rules:
- Recording motion:
The degrees of rotary motion or
centimeters of translatory motion are to be obtained from passive manipulation,
and are to reflect passive (not active) motion at the site being examined. In
the lower extremity, joints are to be observed during weight-bearing, and if the
degree of joint excursion is greater under conditions of loading than under
passive manipulation, this figure is diagramed rather than the smaller figure
(e.g., recurvatum of the knee).
- Translatory motion:
Linear arrows horizontally placed below
the circle indicate the presence of (abnormal) translatory motion at
one or more of the six designated levels of the lower extremity listed on the
left side of the form. The head of the arrow always points in the direction of
displacement of the distal segment relative to the proximal segment. Linear
arrows vertically placed on the right side of the circle indicate(abnormal) translatory motion along the
vertical axis at the site indicated.
- Rotary motion:
Normal ranges of rotary motion about
joints are preshaded on the diagram. Abnormal rotary motion, either as limited
or excess motion, is indicated by double-headed arrows placed outside and
concentric to the circle, to indicate the extent of available motion present in
the affected joint. In certain instances, it may be more meaningful to use two
double-headed arrows in order to describe the range of motion to either side of
the neutral joint axis, rather than a single arrow which describes the total
range of motion present. If one head of an arrow fails to reach the preshaded
margin, limitation of joint motion is denoted. Conversely, if one head of an
arrow projects beyond the preshaded margin, excess motion is designated. Numbers
in degrees are placed adjacent to the arrows to indicate the arc described. In
addition, radial lines drawn from the center of the circle and passing through
its perimeter at the tips of the double-headed arrow are to be used for more
graphic representation of the arc of available motion. At sites where rotary
motion does not occur (e.g., fracture site, or knee joint in the coronal plane),
the presence of abnormal rotary motion is similarly designated by a
double-headed arrow with adjacent numerical value in degrees.
- Fixed position: Double radial arrows indicate a fixed
joint position, and describe in degrees the deviation from the neutral joint
position. Horizontal or vertical double arrows indicate a fixed joint position
in a translatory sense, and the extent of abnormal translation is indicated in
centimeters adjacent to the arrow (e.g.,subluxation of the tibia in a hemophiliac
knee).
- Muscle dysfunction:
- Flaccid muscle:
Flaccid muscle is designated as such
under the section on major impairments. Muscle-group strength, not individual
muscle strength, is determined by conventional means on the examining table, and
the letter grade corresponding to volitional force is recorded adjacent to the
skeletal outline at the proper location for each muscle group. The letter grades
correspond to the standard muscle-grading system used in poliomyelitis. No
symbol is used if muscle strength is normal.
- Spastic muscle: Spastic muscle is designated as such
under the section on major impairments. It is further identified in the legend
as "SP." The letter grade (e.g., SPMO) for muscle-group tone, not
individual muscles, is to be placed adjacent to the skeletal outline at the
proper location for each muscle group. Spastic-muscle estimates are to be made
with the patient in the functional position for the lower extremity, i.e.,
observation during standing and walking. The subletter grades for spastic muscle
are as follows:
"M" indicates a mild degree of
spasticity;
"MO" indicates a moderate degree of
spasticity sufficient for useful holding quality;
"S" indicates severe spasticity,
obstructive in terms of function.
In certain instances, muscle groups in a
patient with spastic paralysis may be more appropriately graded according to
volitional force, e.g., dorsiflexion of the foot in a hemiplegic.
- Recording fracture or bone
deformity: All translatory or rotary motions at the fracture on the shaft of a
long bone are diagramed on the circle located
The technique of completing the analysis
forms for specific lower-extremity disabilities is shown in Fig. 7,Fig. 8,Fig. 9,Fig. 10,Fig. 11,Fig. 12
Discussion
The stated purpose of developing a
patient analysis form of this type is to organize a systematic approach to
orthotic prescription. In addition, through stimulation of a careful appraisal
of biomechani-ical faults in a given extremity, it may also serve as a basis for
identifying certain areas in need of new or further design and development. It
is also viewed as a valuable teaching tool for students of orthotics at both the
technician and physician levels. Most importantly, it may serve as a common
ground upon which both the orthotist and the physician can meet to work out
satisfactory solutions to bracing problems. (Sample copies of the form are
available from the CPRD office).
As a further step in making such an
analysis form more meaningful to orthotists and physicians, a list of available
lower-extremity orthotic components is currently being compiled in such a way as
to categorize these components by their biomechanical function. Ideally then,
one might diagra-matically plot the biomechanical losses present in a limb and
then select a mechanical device from the appropriate category to substitute for
the lost function. In this way, the orthotic prescription can evolve as a
carefully thought-out combination of specific components to create a suitable
orthotic system for the deficient limb.
A revitalized approach to orthotics is
urgently needed. According to a recent estimate, there are 3,370,000 orthotic
patients in the United States as opposed to 311,000 amputees, or ten times as
many patients who need orthoses as need prostheses (1). Little that is
new has been done for many of these patients until very recently. Several
research centers in the United States and Canada are engaged in sophisticated
and promising orthotic research. Unfortunately, by and large, the products of
this research have not yet reached the masses of handicapped people. Stimulation
of new approaches to mechanical design at the local level must be achieved
through close and meaningful collaboration between physician and
orthotist. It is hoped that the material
presented in this article will be an initial step toward that goal.
Work is currently being done on a similar
approach to the upper extremity and the spine. These areas will be the subjects
of future reports.
Acknowledgements
The authors wish to express special
appreciation to Dr. George T. Aitken, former chairman of the American Academy of
Orthopaedic Surgeons Committee on
Prosthetics and Orthotics; Dr. Robert Keagy; Mr. A. Bennett Wilson, Jr.; Mr.
Anthony Staros; and Dr. Edward Peizer for their specific contributions to this
work.
References:
- Committee on Prosthetics Research and Development, Report of the Seventh Workshop Panel on Lower-Extremity Orthotics of the Subcom.it-tee on. Design and Development, National Research Council-National Academy of Sciences, March 1970.
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