Getting Started in Prosthetic-Orthotic
Research
Thomas M. Gavin, CO
Avinash G. Patwardhan, PhD
ABSTRACT
The authors discuss getting started in
O&P research and provide examples
for organizing research projects, including how to identify the basic problem to forming the hypothesis, testing
the hypothesis and drawing statistically
or clinically significant conclusions.
Several common early errors in getting started with a project design are
briefly discussed. Being concise, clear
and significant are shown to be some of
the most important factors in formulating a project. Constraints of time, funding and proper equipment to carry out
research investigations should be considered but can be overcome and should
not discourage the new researcher.
Solving these logistical constraints is
also discussed.
The impact of O&P research is paramount to the future of our field with the
waning physician interest in carrying
out O&P projects.
Introduction
Research is defined as a quest or investigation to reveal truth or to solve a
problem utilizing scientific method.
Research can be as simple as trying several different rivets to decide which is
most suitable for a given application or
as complex as developing a skeletal attachment for a prosthesis.
Correctly investigating an abstract
theory requires much time. We may be
inspired by seeing a repeating clinical
problem or by realizing that a clinical
method we are required to perform
was founded intuitively and based on
unproven assumptions.
However, it may require 10-15 hours
per week for years to investigate a given problem. Clinicians sometimes
abandon research because they were
unaware of the time requirement before they started. Motivation and a
good attitude are essential.
Frequently, ambitions are much
greater than accessible funding and
equipment for the beginning researcher. To start out, it is best to conduct
studies that don't require significant
funding and can be done in the lab or at
home. Familiar surroundings will yield
a certain comfort. This is the best low budget method to begin establishing a
research track record. Clinical studies
of patient acceptance or outcome of a
given method represent a major portion of published research in O&P.
Researchers must have expert clinical understanding of the chosen topic.
Prosthetists/orthotists who spend 90
percent of their clinical time in prosthetics may not be ideal candidates to
conduct orthotic studies. Be sure to
choose a topic relevant to your clinical
practice. Conduct a search of the relevant literature to obtain a thorough understanding of not only the chosen topic, but of previous studies in this area
Do not repeat conclusive studies.
Most departments in medical universities have full-time basic science re
searchers and statisticians who actively
pursue clinicians to become involve
with or conceptualize research projects. Basic scientists are problem solvers, and statisticians are analysts, both
in need of problems to solve and analyze. Clearly, the clinician can present
problems, analyze the clinical significance of the problem, conceptualize
the study and analyze the clinical pertinence of the results.
Identifying a Problem
A problem is the basis for any project.
Solving a problem also may answer a
perplexing question. Common problems are clinical inconsistencies. During the daily routine in O&P we see
much repetition and should be able to
separate consistent from inconsistent
outcomes.
For example, we may fit 100 ankle-foot orthoses in a year and see a consistency in improved gait. However, we
may see all these patients for a one year follow-up and notice that knee extensor tone and power improved in
some patients, remained the same in
some and decreased in others for no
apparent reason. This is a clinical inconsistency and would serve well as a
research problem.
Another common problem is patient
acceptance. Cosmesis, weight and heat
are common complaints about prostheses and orthoses. Development of
newer devices that address these problems frequently arises from lack of patient acceptance. The shorter thoraco
lumbosacral orthoses (TLSO) to replace the Milwaukee brace in the treatment of scoliosis, the postoperative
TLSO to replace the Risser cast and
the endoskeletal prosthesis are direct
results of this problem.
One of the most popular questions to
investigate is which device will function
best for a given condition when several
orthoses or prostheses may be selected
(comparative analysis). For example, a
multitude of knee orthoses exists to
treat the injured anterior cruciate ligament (ACL). All claim to be adequate
in relieviing strain on the ACL and other associated ligaments; however, studies have shown some of the devices
provide only marginal function while
others yield better results.
Answering the question why is invaluable to better understand research
methods. Why do we place the thoracic
pad of a Milwaukee brace at and inferior to the apex of a curve? Why do tonereducing ankle-foot orthoses reduce
tone?
Forming the Hypothesis
A hypothesis is an educated guess. Before forming the hypothesis, answer
some preliminary questions.
- Is the chosen topic clinically relevant? The turnbuckle spinal cast of
Hibbs was abandoned several decades
ago when the Harrington rod became a
standard, so investigating the distractive forces of the Hibbs cast is no longer relevant.
- Has the problem or question been
addressed previously? Is the method
chosen to investigate the problem satisfactory? Is technology available for investigation adequate, and is the design
of the research ethical and legal?
- Are the variables too great to extrapolate a reliable answer? If the project appears to be feasible, conduct a
thorough literature search and form a
base of data.
Pertinent literature would include
biomechanics and kinematics of the device or method variant; the pathology
being treated, including the pathomechanics, neurology, physiology, and kinesiology; and all relevant clinical literature, including conceptual, theoretical and result studies. Once a wealth of
knowledge has been obtained, the researcher must decide exactly what to
investigate.
At this point many variables are apparent. Be clear and concise when stating the hypothesis, and do not include
tangents or too many variables. Each
variable has an exponential result in
increasing the length of the study, and
tangents are usually equivalent to doing a separate study.
For example, the hypothesis,
"Willner's instrument of spinal stabilization is a good predictor of the outcome of orthotic treatment for chronic
low back pain" is simple, concise and
to the point. Willner's instrument is the
device, chronic low back pain is the
pathology and the outcome predictor is
to be investigated.
An example of an overly ambitious
hypothesis with variables and tangents
would be "Willner's instrument of spinal stabilization set in extension for discogenic patients and flexion for spondylotlisthesis and stenosis patients will be a
good predictor of the outcome of orthotic treatment and will assist in delaying and preventing lumbar fusion."
Immediately the statistical analysis is
severely complicated. Instead of analyzing one group of patients to predict
the desired outcome of treatment, as in
the first hypothesis, we have now added several dimensions. We have outcome predictor to investigate, variables of flexion of one group of pathologies and extension in another, and a
tangent that may be unprovable in delaying or preventing surgery. This
clouds the primary point of investigation and leaves the researchers, statisticians and reviewers confused.
In the discussion aspect of the final
paper one may expound on the variables and tangents as long as they are
identified as postulations and conjecture. Discussions of this nature may
motivate the reader to continue this research. The variables and tangents are
not part of the hypothesis and therefore have not been investigated. Take
the project one step at a time and be
thorough when investigating the concise hypothesis.
Methods
Once a problem worthy of investigation is identified, is found, knowledge
about the subject has been gathered
and the hypothesis has been formed,
researchers must decide how far to go.
To make this decision the clinician-researcher must consider all limitations.
To be journal-worthy and accurate, research must have a solid design, and
results must be backed up with sound
statistical analysis.
If these criteria are not met, even the
most clinically significant study on the
largest patient populations will not be
credible and will likely be inaccurate.
Following established criteria will help
to accurately reveal clinical truths and
enable those truths to be shared
through publication.
In vivo studies are studies carried out
in real situations. For example, if the
study is designed to investigate skin
pressures in ankle-foot orthoses and
the measurements and data are derived
from patients or normal human subjects, this is an in vivo study. If data are
derived from a mathematical model or
a surrogate, it is considered in vitro.
There are advantages and limitations
to both types of studies. In vivo studies
are considered to be more accurate;
however, all studies cannot be carried
out on live human subjects.
In Vivo Studies
Retrospective studies are usually done
with data derived from pre-existing
conditions. Although these studies are
objective, they usually lack reliability
and accuracy because facts are gathered from patient records and memory
instead of established research methods. These studies usually yield some
relevant conclusions; however, the
quality would have been improved
greatly if the study were designed prior
to fact gathering.
Prospective studies are carried out
with the research design done prior to
creating the conditions to be investigated. This allows the researcher to alter
record keeping to derive desired data.
Patient questionnaires may be prepared and additional measurements
may be taken during routine patient
management.
The researcher must be careful
about the degree of objectivity practiced in this type of study. Although
one may have high-quality research design and derive all data correctly, the
results may be skewed by variables in
patient management since the clinician
is also the researcher and is aware of
the hypothesis he has set out to prove.
The prospective study is the study of
choice since no design conditions are
based on existing records or memory
for the collection of the data.
In Vitro Studies
The advantage of in vitro studies is that
new ideas may be tried without risk to
human life. An example of an in vitro
study would be to investigate the effects of a new TLSO designed to treat
scoliosis in the high thoracic spine.
These orthoses are not and have never
been advocated to treat these high
curves because it has always been
thought that the Milwaukee brace is
the only orthosis designed to control
scoliosis in that area of the spine. To
speculate that an intuitively designed
orthosis may work and to then test it on
a patient is not only unethical but inherently dangerous and risks putting a
patient through very risky surgery.
It would also be irresponsible if an
experienced clinician researcher designed an orthosis that enables patients
with this condition to be treated with a
more acceptable, more cosmetic orthosis yet not do everything possible to see
if it works. This is a case for an in vitro
study.
A mathematical computer model of
the scoliotic spine and the new orthosis
may be constructed to analyze the new
design for effectiveness. The model
may also allow for the design to be
made even more effective by exploring
variants of the design. Once the modeling study is carried out, the results of
this in vitro study, if acceptable, may be
used as a basis to test the design on
patients and to design an in vivo study.
Cadaver and animal models also may
be invaluable tools in laboratory studies.
The shortcomings of in vitro studies
are that mathematical models are not
capable of considering all the variables
of the human body. Animal surrogates
do not possess the same properties as
humans, and cadavers no longer have
functional muscle, live bone or functional organ systems. These studies
only yield relative data and are useful in
designing in vivo studies and exploring
variables.
Statistical Analysis
In the modern world of medical research, statistical analysis is a must.
Did the researcher have significant
power in the results? Was the population of a statistically significant size?
Was the percentile error low enough?
Did the researcher carry out the correct pairings test? Are the results reliable? These are just some of the questions to address.
Most major research funding agencies like the National Institutes of
Health and the Department of Veterans Affairs require proof of statistical
design before funding a research proposal. Unless you have a solid academic background in statistics, it is best to
either co-author with or consult a statistician before designing the project.
Overcoming Complexities
In the prosthetic-orthotic world it is
difficult enough to practice and understand the daily technical and clinical
complexities of our profession, and
sometimes it appears overwhelming to
consider designing and conducting
studies that include statistical analysis.
Most physicians and other health professionals have decided that the only
way to be credible in research is
through the multidisciplinary approach.
Usually research projects consist of
investigators who are health professionals, sometimes several from multiple specialties, basic scientists and statisticians. Single author papers are usually strong and accurate in one or two
areas but may lack statistical or design
strength, making a feasible project lack
credibility.
Begin with a Pilot Study
Once you feel your project is feasible,
try it on a small scale. Don't worry
about statistics at this point, just try to
get a feel for it. Try five or six cases, do
measurements, collect data and see
where consistencies and inconsistencies are. This is commonly referred to
as a pilot study and is essential to calculate the amount of time and resources
the project will require.
Most funding agencies require results of a pilot study to be included with
the grant proposal. Pilots are usually
low-budget, simple ways of getting
started and working out the "bugs."
They also allow clinicians to make preliminary predictions.
Conclusion
Prosthetics and orthotics is our profession. We can no longer sit back while
physicians and scientists do research
for us. In the past, prosthetists/orthotists may have fit the prosthesis or orthosis, read the manuscript, made last
author on the paper or given an acknowledgement. The time has come for
us to be co-investigators and co-principal investigators. We need to formulate the study, lead and assist in all
phases of gathering and analyzing data,
and draw the conclusions.
Do not feel that conducting research
is "over your head" or is too difficult.
Research is like anything else. Once
you do it a few times you will wonder
why you did not begin sooner.
Thomas M. Gavin, CO, is director of clinical services at BioConcepts Inc., Burr Ridge, Ill., and a research orthotist with Orthopaedic Biomechanics Laboratory, Rehabilitation Research and Development Center, Department of Veterans Affairs Hospital, Hines, Ill.
Avinash G. Pawardhan, PhD, is a professor in the department of orthopaedic surgery, Loyola University Medical Center, Maywood, Ill., and is a director of the Orthopaedic Biomechanics Laboratory, Rehabilitation Research and Development Center, Department of Veterans Affairs Hospital, Hines, Ill.
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