Clinical Evaluation of A Comprehensive Approach To Below-Knee Orthotics
Maurice A. LeBlanc, M.E., C.P. *
This article is essentially a report prepared by the author for and approved by the Subcommittee on Evaluation of the Committee on Prosthetics Research and Development. The work was performed under Contract SRS-72-7, Amendment #1, between the Social and Rehabilitation Service, DHEW, and the National Academy of Sciences.
Over the past few years, a technical analysis form and nomenclature/prescription forms have been developed for the lower limb through efforts of the American Orthotic and Prosthetic Association (AOPA), the American Academy of Orthopaedic Surgeons (AAOS), the Committee on Prosthetic-Orthotic Education (CPOE), and the Committee on Prosthetics Research and Development (CPRD). The goal of the development of these forms has been to provide a means of matching effectively the biomechanical dysfunctions of patients with the biomechanical benefits of orthoses. At the same time there have been several new ankle-foot orthoses (so-called "drop-foot braces") developed recently.
The evaluation project was undertaken to assess the usefulness of both the new forms and the new orthoses, especially in combination, for patients and clinicians. Therefore, it is an evaluation of a comprehensive approach to treatment of below-knee orthotic patients, using three forms developed for patient analysis and prescription and using three promising ankle-foot orthoses (AFOs).
The forms chosen for the evaluation were:
- AAOS Lower-Limb Technical Analysis Form
- COPE Orthotics Prescription Chart-Tentative
- Institute of Rehabilitation Medicine (IRM) Patient Classification related to AFOs .
The orthoses chosen for the evaluation were:
- IRM Spiral AFO
- Texas Institute for Rehabilitation and Research (TIRR) Polypropylene AFO
- Veterans Administration Prosthetics Center (VAPC) Shoe-Clasp AFO .
The clinics that participated in the evaluation were:
- Northwestern University (NU) Prosthetic-Orthotic Center
- New York University (NYU) Prosthetics and Orthotics
- Rancho Los Amigos Hospital
- University of California, Los Angeles (UCLA) Prosthetic-Orthotic Program
- University of Miami Department of Orthopaedics and Rehabilitation
- University of Virginia Department of Orthopedics
- Veterans Hospital, Cleveland
- Veterans Administration Prosthetics Center (VAPC) Patient Service Clinic
It should be noted that the VAPC Patient Service Clinic was not involved in the clinical trial of the VAPC shoe-clasp AFO.
Description Of Forms
Aaos Lower-Limb Technical Analysis Form
This form, along with the explanation of its use, is included as Appendix A. Newton C. McCollough, III, M.D., is largely responsible for its development.
Cpoe Orthotics Prescription Chart (Tentative)
This form along with the explanation of its use is included as Fig. 1. Jacquelin Perry, M.D., is largely responsible for its development.
Irm Patient Classification For AFOs
This form is included as Fig. 2. Its use is fully explained in reference .
Description Of Orthoses
IRM SPIRAL AFQ (Fig. 3 )
To permit controlled plantar flexion, dorsiflexion, eversion, and inversion of the foot while allowing normal transverse rotation during gait.
The spiral AFO is made of Plexidur thermoplastic in two pieces—a shoe insert with spiral upright and a calf band. The elasticity of the material provides the forces needed for foot control. The calf band has an opening below the fibular head which permits donning. No straps are required to hold the orthosis in position. It is light in weight and not easily noticed.
The spiral AFO is indicated for complete flaccidity of the foot, and it can accommodate moderate spasticity. It is contraindicated where severe spasticity, fixed varus or valgus deformity, or swelling exists.
A plaster cast of the foot and lower leg is taken, the plaster model is modified, and a precut Plexidur pattern is heated to 275 deg. F. and formed over the model. The orthosis is then trimmed and fitted carefully.
TIRR POLYPROPYLENE AFO (Fig. 4 )
To assist dorsiflexion of the ankle during swing phase without conventional shoe attachment and to assist mediolateral (M-L) stability during stance phase.
The TIRR AFO is a one-piece orthosis of polypropylene thermoplastic formed over a plaster model of the foot and lower leg, and is reinforced with corrugations in the material. The springiness of the material provides the dorsiflexion force. It is light in weight and not easily noticed.
The TIRR AFO is indicated for lack of dorsiflexion and can accommodate moderate spasticity. It is contraindicated where severe spasticity, fixed deformity, or swelling is present in the foot-ankle complex.
After making a plaster model of the foot and lower leg from a plaster cast of the patient, the model is modified by judiciously adding teflon rod on the surface of the model to make corrugations in the orthosis to provide additional resistance to bending. The polypropylene is heated to 400 deg. F. and formed over the model. It is trimmed carefully, a Velcro closure is added on the calf band, and then it is fitted. Additional trimming of material provides less resistance to plantar flexion.
VAPC SHOE-CLASP AFO (Fig. 5 )
To provide a force to hold the foot in a neutral or slightly dorsiflexed position during swing phase and to assist M-L stability during stance phase.
The shoe-clasp AFO is made of prefabricated components—a clip which fits on the counter of the shoe, an epoxy-fiberglass posterior bar, and a calf band. It can be clipped on any stiff-counter shoe and is light in weight and not noticed easily.
It is indicated for "drop foot" condition and can accommodate mild spasticity. It is contraindicated where marked M-L instability or spasticity exists.
The prefabricated components are carefully assembled and fitted with special attention to the fit of the clip on the shoe and the placement of the calf band.
An orientation session was held on January 10-14, 1972, at NYU for CPRD and the developers to familiarize the clinic teams with the forms and orthoses to be evaluated and with the evaluation procedures.
Selection Of Patients And Clinical Fittings
The clinic teams, upon returning home, selected patients according to the developers' prescription criteria. In examining the patients and prescribing the orthoses, the three forms to be evaluated were used by the clinic teams. The patients, when considered suitable, were fitted with one of the three new orthoses for a trial-wear period of at least one month. Before and after this time, evaluation sheets were completed by the clinic teams to report the results.
The CPRD staff made site visits to all of the clinics at least once, and twice in most cases, during the evaluation. These visits were helpful in assessing the progress, in resolving minor problems, and in supplementing information in the evaluation folders.
Subcommittee On Evaluation Meeting
The Subcommittee on Evaluation met on August 21-22, 1972, in Annapolis, Maryland, to discuss the results of the evaluation with the clinics and developers .
Types Of Patients
The three AFOs were fitted to patients with the following dysfunctions:
Image 2 Image 3
Numbers in parentheses indicate bilateral fittings.
Hemiplegics comprised half of all patients.
Most patients had abnormal balance and many had significant upper-limb involvement.
Most unaided gaits were typified by foot drop, insufficient push off, excessive medial foot contact, and abnormal walking base.
Walking aids were used by half of all patients. A few evaluation folders were lost in the mail, so the above list includes only 55 of the total 67 patients.
Summary Of Experiences With The Three Forms
AAOS Lower-Limb Technical Analysis Form
There was positive response by most clinics. Physicians, therapists, and orthotists generally found it helpful and worthwhile. Several suggestions were made for improvement of the form and have been given to Dr. McCollough to consider.
CPOE Orthotics Prescription Chart-Tentative
This was generally approved by the clinics but with a substantial number of negative comments. Clinicians were divided on whether they would continue to use it. Most of the criticism was that the form was ambiguous and insufficiently detailed and that good clinic teams "don't need it." However, all recognized the potential value of the form especially for teaching, and that the AFOs involved only a small simple portion of the overall scheme.
IRM Patient Classification for AFOs
There was divided acceptance of this form. The sense was that it is an excellent categorization of patients for AFOs, but that few of the clinics would prefer to use this type of "cookbook" approach.
Summary Of Experiences With The Three Orthoses
IRM Spiral AFO (Image 1 )
There was very favorable patient acceptance of this orthosis. The main advantages are cosmesis, lightweight, allowance for transverse rotation, some assistance for push-off. and inter-changeability of shoes. The main disadvantages are skill and time required for proper fabrication and fitting.
TIRR Polypropylene AFO (Fig. 7)
There was also very favorable patient acceptance of this orthosis. The main advantages are
cosmesis, lightweight, adjustability in dorsiflexion assistance by selection of trim, and inter-changeability of shoes. The main disadvantages are the skill and time required for proper fabrication and fitting.
VAjPC Shoe-Clasp AFO (Fig. 8 )
This orthosis was especially popular with the orthotists as well as the patients because it is prefabricated and can be applied quickly and easily. As with the others, the main advantages include cosmesis, lightweight, and interchangeability of shoes. The main disadvantage in these fittings were minor mechanical problems which the developer is attempting to solve.
AAOS Lower-Limb Technical Analysis Form
It was the consensus that this form is a good vehicle for teaching, for communicating between disciplines, and for record purposes. However, no unanimity was reached on whether its use would be beneficial for experienced clinicians on a routine basis.
CPOE Orthotics Prescription Chart-Tentative
It was the general feeling that this form is worthwhile but needs to be evaluated with cases more complex than those requiring only AFOs before further assessing its potential use.
IRM PAtient Classification For AFOs
This is a form which exists and is used by IRM. Anyone who finds it helpful is welcome to use it. The participants at this meeting did not feel strongly enough about it to recommend its routine use in clinics.
The Three AFOs
All three AFOs were found to be suitable and worthwhile devices for patient use. To help decide when one should be used over the others, a prescription chart (Table 1 ) was prepared to clearly delineate the differences in use between the three AFOs and to serve as a guide for their applications. All three are recommended for routine clinical application and for instruction in the prosthetic-orthotic schools. There were some suggestions for improvement of each of the devices. These have been brought to the attention of the developers.
Appendix A Draft: Definitions And Rules For Technical Analysis Form
- Translatory Motion — 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.
- Rotary Motion — Motion of a distal segment in which one point in the distal segment or in its (imaginary) extension always remains fixed.
- Rules pertaining to 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 addition, however, joints are to be observed during weight bearing, and if the degree of joint excursion is greater under conditions of loading than by 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 as excess motion, is indicated by a double headed arrow placed outside and concentric to the circle, to indicate the extent of available motion present in the joint on the side (or sides) of the neutral joint position which is affected. The double headed arrow thus described the available range of motion on the affected side (or sides) of the neutral point position. If one head of the arrow fails to reach the preshaded margin, limitation of joint motion is denoted. Conversely, if one head of the 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., subluxed tibia in a hemophiliac knee).
- Rules pertaining to muscle dysfunction
- Flaccid muscles
Flaccid muscle is designated by the symbol "FL", and its grade by sub-letter as indicated in the legend. The letter grade (e.g., FLp) for
p strength (e.g., knee extensors), not individual muscles, is to be placed adjacent to the skeletal outline at the proper location for each muscle group. Flaccid muscle strength estimates are obtained by conventional means on the examining table, and correspond to the conventional grading system for poliomyelitis. No symbol is used if muscle strength is normal.
- Spastic muscle
Spastic muscle is designated by the symbol "SP", and its grade by sub-letter as indicated in the legend. The letter grade (e.g., SPmo) for muscle group strength, 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 sub-letter 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
- Rules pertaining to 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 at the mid-shaft of each bone. The actual fracture site is indicated by the fracture symbol. All bony deformities such as valgus angulation of the shaft are likewise diagramed on the circle located at the center of the shaft, regardless of the position of the angular deformity. The location of the angular deformity is designated by circling the appropriate level of the left hand side of the chart.
- Rules pertaining to limb length
Clinical measurements are to be made and the discrepancy in length is to be recorded in the appropriate space on the front sheet for the following:
Ischial tuberosity to sole of heel
Ischial tuberosity to medial tibial plateau
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.
- Rules pertaining to balance
Balance is estimated during gait and recorded on the front sheet as follows:
Mild impairment of balance is compatible with independent ambulation. Moderate impairment of balance is compatible with ambulation plus external support.
Severe impairment of balance necessitates personal assistance for ambulation or standing.
Appendix A Appendix A (cont..) Appendix A (cont..) Appendix A (cont..)
- Clinical Evaluation of a Comprehensive Approach to Below-Knee Orthotics, Report E-6, National Academy of Sciences, Washington, D.C., 1972.
- McCollough, Newton C. III, M.D., Charles M. Fryer, M.A., and John Glancy, C.O., "A New Approach to Patient Analysis for Orthotic Prescription -Part I: The Lower Extremity," Artificial Limbs, 14:2:68-80, Autumn 1970.
- Harris, E.E., (article in this issue of Orthotics and Prosthetics)
- Sarno, John E., and Hans Richard Lehneis, "Prescription Considerations for Plastic Below-Knee Orthoses," Archives of Physical Medicine and Rehabilitation, 52:22:503-510, November 1971.
- Lehneis, M.R., "New Concepts in Lower Extremity Orthotics," Medical Clinics of North America, 53:3:585-592, May 1969.
- Lehneis, Hans Richard, Warren Frisina, Herbert W. Marx, Glenn H. Goldfinger, Plastic Spiral Below-Knee Orthosis (Manual), Institute of Rehabilitation Medicine, New York University Medical Center, January 1972.
- Engen, Thorkild J., "The TIRR Polypropylene Orthosis," Orthotics and Prosthetics, 26:4:1-15, December 1972.
- Engen, Thorkild J., Instructional Manual for Fabrication and Fitting of a Below-Knee Corrugated Polypropylene Orthosis, Texas Institute for Rehabilitation and Research, Houston, September 1971.
- Greenbaum, Werner, VAPC Equinus-Control Ankle-Foot Shoe-Clasp Orthosis (Draft Manual, Veterans Administration Prosthetic Center, New York, 1971.
- Report of Fourteenth Meeting of the Subcommittee on Evaluation Held on August 21-22, 1972, Committee on Prosthetics Research and Development, National Academy of Sciences-National Research Council, Washington, D.C.