Functional Evaluation of a
Custom-Molded Leather
Ankle Lacer
Charles L. Saltzman, MD
Donald G. Shurr, CPO, PT
John Kamp, CO, OPA
Thomas M. Cook, PHD, PT
ABSTRACT
The purpose of this study was to evaluate the efficacy of a custom-molded
leather ankle lacer for treating painful
problems of the ankle and hindfoot. The
evaluation involved patient self-assessment, clinical examination and radiographic determination of the effectiveness of the ankle lacer.
Overall, patients who used the lacer
experienced moderate pain relief with
significant but not complete restriction
of motion. Based on this study and clinical experience, the authors concluded
the leather ankle is a compliant and
comfortable treatment strategy for patients who desire some retained motion
of the ankle and hindfoot without intolerable pain.
Introduction
Arthritis frequently affects both the ankle and hindfoot. Studies show 17 to 20
percent of patients who have rheumatoid arthritis initially experience symptoms in the foot and ankle areas; in the
later stages of the disease, foot and ankle complications affect 90 percent of
patients (1).
Initial treatment of this condition
typically involves activity modification
and use of oral anti-inflammatory
agents. If these measures fail, orthoses
to reduce motion and unload the affected joints may be considered. Currently, the most popular approaches
typically involve fabrication of a polypropylene ankle-foot orthosis (AFO).
Although this method is generally well-tolerated, it sometimes causes difficulties such as excessive restriction of motion, skin irritation, or gradual loss of
it due to leg atrophy or volume reduction.
At the University of Iowa, the custom-molded leather ankle lacer (see
Figure la
and Figure 1b
) has been used for
more than 50 years to treat selected patients who have had chronic ankle or
hindfoot problems-since Jordan first
described the application of leather
racing to treat problems of the ankle
(2). The leather ankle lacer remains a
viable alternative to modern synthetic
orthoses because of its apparent acceptance by patients.
The present study assesses the lacer's effectiveness in pain relief and restriction of motion. To the authors
knowledge, no text concerning custom-molded leather ankle orthoses, other
than Jordan's paper on the modification of a knee corset, exists.
Materials and Methods
Subjects
Five patients from the University of
Iowa Hospital and Clinics participated
in this study. Each patient wore one
leather ankle lacer and was evaluated
and/or treated in the contralateral lower-extremity area. Since each patient fit
the profile being studied, a formal selection process was not necessary. All
patients signed informed consent forms
approved by the institution's Human
Subjects Review and Radiation Protection committees.
The study group was comprised of
three women and two men. The mean
age of the group was 66 years, with ages
ranging from 53 to 79 years. The average length of lacer wear was 5.5 years.
Basic subject data are presented in
Table 1
.
Procedures: Subjective Evaluation
A written questionnaire (see Table 2
)
and personal interviews were the methods used to subjectively evaluate the
orthosis. Patients were asked about:
- their ability to function both with
and without the lacer,
- how many hours each day they
wore the lacer,
- their daily activity levels,
- the lacer's appearance and comfort, and
- overall satisfaction with the custom-molded leather ankle lacer.
Procedures: Physical Examination
During the physical examination phase
of evaluation, the condition of each patient's skin underneath the orthosis was
examined; the presence of any calluses
or ulcers was noted. Calf atrophy was
determined by measuring the calf circumference 10 cm below the medial
knee joint line and comparing that
measurement with a congruous measurement of the contralateral lower leg.
Range-of-motion (ROM) measures for
the ankle and subtalar joints were taken with a goniometer.
Procedures: Three-Dimensional
Electrogoniometry
A three-dimensional electrogoniometer
constructed from mutually perpendicular potentiometers was used to measure
motion (see Figure 2
). Patients were instructed to maximally flex, extend and
rotate their ankles. Motion was measured with and without use of the lacer
in the sagittal and frontal planes.
The method's reliability was determined by comparing electrogoniometnc measurements to those made from
radiographs. Comparisons were performed between free active ROM and
measured ROM with the lacer in place
in the weightbearing position.
Procedures: Radiographic Analysis
Sagittal plane motion also was determined radiographically. Four lateral
X-rays of each foot and ankle were taken by a standard protocol (see Figure 3
).
Radiographs were taken in maximum
flexion and maximum extension phases
both in and out of the lacer. From these
lateral X-rays, motion was measured in
the ankle, hindfoot and midfoot.
Ankle motion was determined by
changes in the tibiotalar angle. The tibial axis was defined by a line drawn between the medial and lateral cortex
parallel to the long axis of the bone.
The talar axis was determined using the
method of Digiovanni et al. (3).
Hindfoot motion was measured by
changes in the talocalcaneal angle. The
calcaneal axis was defined by a line
drawn tangent to its interior surface.
Midfoot motion was determined by
changes in the tab-first metatarsal angle. The first metatarsal axis was defined by a line longitudinally bisecting
its shaft.
To reduce the error of measurement,
lines were drawn on each X-ray three
times by two examiners. The mean differences between flexion and extension
values were used to indicate sagittal
plane motion. These differences between angles, with and without the orthosis, represented the restriction of
motion from the lacer. Data were analyzed using Systat statistical software.
Fabrication of the Custom-Molded
Ankle Lacer
The custom-molded leather ankle lacer
was fabricated for each patient using a
standard methodology consistent with
the axial resist AFO method taught at
Northwestern University (4). The impression of the foot and ankle is taken
carefully with consideration of the anticipated amount of necessary correction or accommodation. In this position, the ankle often rests in slight
pronation with compensatory forefoot
supination (5); complete correction of
the deformities may not be possible
and usually is not well-tolerated by patients. Following the negative impression, a positive model is made and
modified with careful attention to overall cylindrical reduction in circumference to provide loading on the leg.
Smooth molding leather is soaked in
water, secured to the model and allowed to dry completely. Soft lining
leather is stretched under the molding
leather and covered with a plastic wrap
that acts as a barrier. Once dry, the
leather is cut off the model anteriorly,
making room for the tongue to be
added later. Eyelets or Velcro(r) roller
loops are applied. The metal stays, carefully contoured to produce the desired
support, are added to the medial and
lateral sides of the lacer. Leather stay
covers are glued over the metal stays.
Trimlines generally resemble those
of other AFOs: mid-metatarsal head,
neck of the fibula, and slightly above
the apex of the gastrocnemius muscle
bellies posteriorly (5). Polyethylene or
mesh wire may be substituted for the
metal stays for more general support.
Both materials are "sandwiched" between the two leather layers. The trim
lines of the orthosis shown in Figure 1a
appear proximal since a prosthetic foot
was used in the photograph.
Results
Subjective Evaluation
The five patients involved in this study
reported the lacer relieved pain in all
cases (pain was reduced but not eliminated). Each patient's ability to function in various situations was difficult
to assess due to the general low level of
activity of the subjects involved.
Four of the five patients used the lacer throughout the day. One of the five
reported the lacer was "very comfortable"; the remaining four found it
"somewhat comfortable." Three of the
live added their own padding to improve their comfort levels.
Only two of the five found the lacer
cosmetically acceptable. Despite the
cosmetic concerns, three of the subjects
rated themselves as extremely satisfied,
and two of the five rated themselves as
moderately satisfied. No patient claimed
to be dissatisfied.
Physical Examination
The lacers were well-tolerated by the
skin in all cases. The authors found no
areas of erythema or ulceration. Compared to the uninvolved side, there was
an average 2.2 cm atrophy in the calf circumference of the involved leg (n = 3).
Three-Dimensional Electrogoniometry
The three-dimensional goniometric
measurement of total sagittal plane
motion was compared in each case to
the radiographic measurement of that
motion. The correlation between these
measures was strong (R2 = 0.79), suggesting the validity of the electrogoniometric technique and its potential clinical utility.
All patients demonstrated decreased
motion in both the frontal (axial) and
sagittal planes resulting from use of the
orthosis. A typical example of a patient's motion with and without the orthosis is shown in Figure 4
. The electrogoniometer was especially helpful in
measuring motion in the frontal plane,
which cannot be fully examined by conventional radiography. A 70-percent restriction in frontal plane motion was
found in the subjects using the leather
lacer (p < .002) (see Figure 5
).
Radiographic Results
The radiographic results (see Table 3
)
showed a significant decrease in sagittal plane motion in the involved ankle
and hindfoot resulting from use of the
orthosis. The midfoot motion was not
significantly reduced.
The largest reduction in motion occurred at the tibiotalar joint where motion was reduced an average of 8.9 degrees, representing a 26-percent reduction from the maximal amount of unrestricted ankle motion. The decrease in
sagittal motion at the subtalar joint was
4.4 degrees, representing a 50-percent
reduction.
Discussion
The findings of this study confirm the
authors' clinical experience with use of
the custom-molded leather ankle lacer.
The lacer is generally well-tolerated
and affords pain relief, motion restriction and functional improvement. Although the amount of pain relief was
only moderate, it was consistent.
The results may reflect a selection
bias since the authors evaluated only
long-term users of the lacer. Patients
who were dissatisfied with its use probably would have discontinued use. No
attempt was made to compare the
leather lacer with other treatment orthoses such as rigid, polypropylene
AFOs. Therefore, the subjective results
are anecdotal.
The degree of motion restriction also
was moderate. In the sagittal plane, the
authors found an average 26-percent
decrease in motion at the ankle joint, a
10-percent decrease in the subtalar
joint and negligible change in the midfoot. The effect on frontal plane motion
was more profound. With use of the
electrogoniometer, the authors found
an overall 70-percent decrease in motion (see Figure 5
).
These data suggest that, in terms of
motion restriction, the best indication
for use of the custom-molded leather
ankle lacer is the presence of ankle or
hindfoot hypermobility in the frontal
plane. Since all patients reported some
degree of comfort while wearing the
lacer, it can be presumed they were
more uncomfortable without it; this explains the continued use.
Modification of existing orthoses, or
new impressions and new orthoses,
might have yielded different results.
Rubin reported consistent loss of volume while wearing patellar-tendon-bearing (PTB) orthoses as well as concomitant loss in ability to off-load
forces on the heel, secondary to the volume reduction (6). Perhaps a similar
situation exists with the lacer.
In the authors' practice, the leather
ankle lacer is primarily prescribed as an
alternative to rigid polypropylene, solid
ankle-foot orthoses. The lacer tends to
provide sufficient stability while allowing some motion. Unlike more rigid
AFOs, the lacer more easily allows for
changes in calf volume and may help
unload the hindfoot in stance phase (7).
Conclusion
The paucity of skin problems makes
this device particularly helpful to patients on long-term corticosteroids
with vasculitis or fragile skin. Although
three of the five patients maintain they
added padding for comfort, evaluation
indicated these additions were made in
an effort to deal with volume loss and
increased pressure on the medial midfoot.
Acknowledgments
The authors thank Suzanne Chess and Erin
Shanks for assistance with data collection
and analysis. The authors also would like to
recognize Dr. James V. Nepola for encouragement with the study.
CHARLES L. SALTZMAN, MD, is an associate professor of orthopedic surgery in
the department of orthopedic surgery at the
University of Iowa Hospital and Clinics,
Iowa City, IA 52242-1009.
DONALD U SHURR, CPO, PT, is eastern district manager of American Prosthetics Inc., 2203 Muscatine Ave., Iowa City, IA
52240.
JOHN KAMP, CO, OPA, is manager of
American Prosthetics Inc., 1414 Lombard
St., Davenport, IA 52804.
THOMAS M. COOK, PHD, PT is project
director of the physical therapy educational
programs at the University of Iowa, Iowa
City, IA 52242.
References:
- Black JR, et at. Pedal morbidity in
rheumatic diseases. J Am Podiatr Assn
1976; 66:227.
- Jordan HH. Orthopedic appliances.
Springfield, Ill.: Charles C. Thomas, 1939,
136.
- Digiovanni J, Smith R. Decision making in foot surgery: selected papers from
the fourth annual Northlake Seminar, 4th
ed. New York: Stratton Intercontinental
Medical Book Corp., 1984.
- Orthotic manual 1995: Axial resist
AFO. Northwestern University Orthotic
Center, Chicago, Ill.
- Simons BC, Jebsen RH, Wildman LE.
Plastic short leg fabrication. Orth Pros September 1967; 21 :215-8.
- Rubin G. The patellar-tendon-bearing
orthosis. Bull Hosp Joint Disc 1972;
33:2:155.
- Carlson JM, Hollerback F, Bruce D. A
calf corset weightbearing ankle-foot orthosis design. JPO 1991; 4:1:41-4.
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