CGA FAQ: Applications of Clinical Gait Analysis

Dear All,

I've got to give a talk to the European Federation of Ortopaedic and Trauma
Surgery on the 5th June with the title "Gait Analysis: the State of the
Art". I'm splitting the lecture into three: Technology, Understanding and
Clinical Uses.

How about an honest debate on real clinical uses. I'm obviously aware of the
use of gait analysis in relation to CP (and to a lesser extent in relation
to Spina bifida). In what other fields though does gait analysis have a well
defined and proven clinical role?

In this I'd like to distinguish between research and routine service
provision. I'm interested primarily in routine clinical services.

Richard

Richard Baker
Gait Analysis Service Manager
Musgrave Park Hospital
Stockman's Lane
Belfast BT9 7JB

Tel:  028 9066 9501 ext 2849
Fax: 028 9068 3816

We use it routinely for pre-operative assessment in adults with
traumatic brain injury and stroke. We recently presented data at the
American Academy of Orthopaedics meeting on its value to level the field
for surgical planing in experience and less experienced surgeons. 
Also we use it for orthotic and prosthetic management. The trick here is
to have a clinician that can make use of the kinetic, kinematic and EMG
data (when appropriate) to answer specific clinical questions. Good luck
in your presentation.

Alberto Esquenazi, MD
Director Gait & Motion Analysis Laboratory and
Regional Amputee Center 
MossRehab a Member of the Jefferson Health Network
1200 West Tabor Rd.
Philadelphia, PA 19141 USA
Voice: 215 456 9470  Fax: 215 456 9631
http://www.einstein.edu/phl/1214p2.html


Richard's provocative question prompts some reflection.

It is interesting that the birth of modern gait analysis (at Berkely
under Verne Inman and Howard Eberhart) was stimulated by a desire to
improve lower-limb prosthetics for the returning veterans of World War
II - for those interested, I have started to put together a history page
on CGA - it's by no means complete and in a state of construction, but
you're welcome to take a look and send me anything you think would be
useful:
/history

Anyway, what is startling, I think, is how small a proportion of gait
labs today look at amputees. I might be wrong, but on my travels around
the globe nearly all labs I've noticed that nearly all labs are
predominantly interested in cerebral palsy. Is there a reason for this
change in emphasis, I wonder? I have some suggestions:

¤ 1. There are more people with CP than there are amputees - I don't
think so, but I don't know for sure (perhaps someone could comment?)

¤ 2. The insights provided by computerized gait analysis are unhelpful
in designing and aligning a better prosthesis;

¤ 3. Modern equipment is more suited to 3D and rather superfluous for
most amputee studies (when 2D suffices);

¤ 4. Prosthetics research has simply "gone out of fashion".

Much as it pains me to say so, I suspect  #4 is the reason. Which begs
the question: what will come into fashion when CP is no longer a la
mode?

Chris
--
Dr. Chris Kirtley MD PhD
Associate Professor
HomeCare Technologies for the 21st Century (Whitaker Foundation)
NIDRR Rehabilitation Engineering Research Center on TeleRehabilitation
Dept. of Biomedical Engineering, Pangborn 105B
Catholic University of America


Gait Analysis has been very helpful in the selection and design of lower-limb 
orthotics. As a team member of a local gait lab, I've found the information 
useful in designing FO's and AFO's for neuromotor and orthopedic 
dysfunctions. Often a physician or therapist will make a generic request for 
a brace or a splint. Usually, for an AFO, the focus of the request is the ROM 
of the talocrural joint in the sagittal plane. Often the pathomechanics are 
much more complex, and the design and function of the device can have a 
profound effect on the foot and ankle complex, as well as function up the 
kinetic chain.
As someone involved in gait interpretation for several years, I am mystified 
at the blatant disregard for the inclusion of orthotist and prosthetist in 
gait analysis. The benefit to the clinical team and the patient is obvious. 
The selection of an orthosis is not like the selection of a drug or DME 
device. The prescription that reads "AFO" can yield vastly different designs 
and results depending on the way it is made by the orthotist. No matter how 
detailed the prescription, the orthotist must make decisions that will have a 
significant impact on the fit and function of the device. To pretend 
otherwise results in less than optimum results.
If there is a group that should be intimately involved in gait analysis it is 
orthotist and prosthetist. There is no question of the functional and 
developmental benefits gait analysis gives the patient population served by 
this group.

Locke Davis, CPO 

I think you make some interesting points in the progression
of the use of gait labs.  From a total outsider and my interest laying in
sport, I do not have a clear idea of the path but has money played a role in
this.

My understanding is that the proliferation of gait labs came as a result of
insurance companies requesting objective results of surgical interventions
for CP kids.  Large surgical procedures generate significant income for
especially surgeons as well as hospitals.  The supply of prosthetics does
little for this income.  Do you think this has played a part or am I being
cynical.
Regards
Peter Blanch

I just got a call from xxx, they are putting together a
proposal to study gait with different prosthetic knee designs.  Rancho Los
Amigos Medical Center has recently (within the last 5 years or so) published
studies on gait with different foot designs.  Chris Powers work, at Rancho at
the time, demonstrated the need for EMG in amputee gait analysis instead of
just calculated moments and powers.  I think CP is big because that is where
the money is.  Shriner's has money.

Kay Cerny

In our lab at the West Midlands Rehabilitation Centre, Birmingham, we have been using gait
analysis over the past few years in two main areas: Orthotics and Prosthetics.

One of our first clinical services was to use the GRF vector superimposed over a sagittal and
coronal video view to assist correct prosthetic alignment for LL amputees (particularly
above-knee).  I agree with Chris's opinion that there seems to be a decline in requests for
assessment of amputees.  Over the last five years we have increasingly used the lab facilities
to assess regional orthotic patients with complex problems, referred following failure of
previous medical/ orthotic/ physiotherapy etc. treatment.  Most of those patients are adults
with an original diagnosis such as MS, polio, muscular dystrophy and CVA, complicated by
secondary problems of a biomechanical nature.  More recently we have also seen two other
categories of patients: children with juv. chronic arthritis who had not been treated
successfully previously, and dysvascular patients for limb salvage (many with previous
amputations).

We feel that the facilities of our gait laboratory, and very significantly our
multi-disciplinary team approach (including physician, clinical scientist, physiotherapist and
orthotist/ prosthetist/ podiatrist depending on the patient, in agreement with Locke Davis'
comments), allow us to investigate both the primary problems and secondary complications in
much more detail, in order to recommend the most appropriate treatment/s.  In case of
orthotics, it also allows us to calibrate the device to provide an optimum effect for the
patient, and subsequently to evaluate the orthosis' effect .

Regards to all,

Alexandros Falkonakis MSc PgC MCSP
Clinical Specialist Physiotherapist
Clinical Measurements Laboratory
West Midlands Rehabilitation Centre
91 Oak Tree Lane, Selly Oak
Birmingham B29 6JA, U.K.
Tel: +44 (0)121 627 8123
Fax: +44 (0)121 627 8210



Working, as I do, in a lab that was founded to support the rehab of 
amputees, but is also now predominantly CP-based, I have the 
following comments to make.

There was undoubtably a phase when the study of basic 
biomechanics of walking was essential in order to progress the 
development of functionally effective prosthesis. Once that core 
knowledge on the role of a prosthesis in amputee gait was 
established, it appears to me that further developments in the field 
have had more to do with the incorporation of modern materials and 
methods for improved realisation of this role, than with more 
sophisticated understanding of gait. For example, today we see 
much of the gait-based research directed at trying to test the 
claims of manufacturers about the energy storing capabilities of 
their feet and the subsequent effect that this has on function. 

Following this period, there was a phase when gait analysis was an 
important tool in the training of prosthetists and the development of  
teaching materials, helping to illustrate to them the biomechnical 
basis of the effects of the alignment changes that they were 
making. Again this has led to an increase in the core knowledge 
which prosthetists  now apply in their daily practice.  

The prosthetists makes adjustments to a limb, intuitively 
interpreting the gait changes in terms of the position of the 'load-
line', relative to the limb. He/she does this fairly efficiently and 
efficiently and would need a good excuse to use a gait lab to 
interfere with this process, even with the modern super-fast, 
intelligent systems.

Hence the routine use of gait analysis in prosthetic management 
hasn't been extensive.

Having said all that, with the bewildering array of sophisticated and 
expensive prosthetic systems on the market, I believe that the tide 
is turning. Some of the systems have so many configuration 
choices and are so 'non-anatomical' in their construction, that 
objective support for the clincial decision-making process would be 
welcome (we have had an example of this recently); the routine 
audit of prescriptions may become an important tool in rationalising 
service provision; also the trend to 'intelligent' prostheses, with time-
criticial functions, again lends itself to objective measurement as 
part of the CDM process. Also, even the best prosthetist will find 
himself pitched against a 'problem' amputee, whom it is impossible 
to satisfyand again, objective measurement may come to the 
rescue.
 
Also, your comment about the 3-D systems being superfluous is 
possibly valid for BKs(sorry TTAs!), but I do not believe that they 
are valid for AKs(sorry TFAs!). This is because the various socket 
types and their claims with regards to ischial containment can only 
really be tested looking at M-L hip moments and it is in 
ab/adduction of the prosthesis that these effects are controlled, in 
the main. 

The situation in CP is very different. Yes gait analysis has taken  
our understanding of the subtleties of gait to a new level, applying 
this knowledge to education and directly to new treatments. Yes 
those who have been practising for a long time can recognise gait 
patterns and relate them to functional types and likely treatment 
options. But fundamentally you cannot see in 3-D, you cannot 
confirm moments or muscle activation patterns by observation. And 
most importantly unlike alignment changes, when you simple undo 
a particular component alteration, you cannot undo an injection and 
you certainly cannot undo surgery.

I would hope that CGA is not only here to stay in CP management, 
but that it will become mopre widey accepted, and in the long term 
the case is the same for the mangement of most complex 
ambulatory conditions, once the clinical structures to incorporate 
CGA into their managment exists. For example, our Neuroscience 
department are evaluating the use of CGA as an outcome measure 
in the use of deep brain stimulation, for the mangement of tremor in 
Parkinson's Disease. I mention this to illustrate the importance of 
the clinical support, as it was the interest of the Neurosurgeon and 
his desire to proceed, that drives this forward. There are plenty of 
less exotic examples to choose from and I look forward to hearing 
from other CGAers what they are doing.

Regards

Jeremy Linskell

I have read with some interest of the variety of candidate groups that might
benefit from CGA. Working in a lab with a client base comprising 95% CP, I
am keen to add a little variety to my life. However, to be an effective
decision making or even diagnostic tool, cga can only be used in conjunction
with a decent model of interpretation. This model, in principle, may be
constructed from experience or deterministically (if we were biomechanically
and aetiologically clever enough). In CP, we prefer the experiential
approach (sometimes our own experiences and sometimes the experiences of
others reported in books or journals). I guess that any deterministic
approaches are confounded because, with the data we have available, the
biomechanical problems problems presented cannot be fully determined. The
empirical model may be revised relatively quickly when we are able to do
repeat analyses to assess the effect of our interventions.

The problem with performing a cga on subjects with some of the conditions
mentioned in previous correspondence is the number of individuals you would
need to get referred to to build up a useful experiential model. For
example, we have seen a few peeps with poliomyelitis, yet I find it
difficult to draft a report with added value (yes, muscular weakness; yes
hyperextension; yes, the world is roughly spherical). What is there in these
instances that a keen eye and a few clinical test could not detect?
Certainly, the only role for cga here is to report the effects of
interventions.

Jeremy reported the use of gait analysis as an outcome measure after deep
brain stimulation in Parkinsonism, but I have my doubts about the
appropriateness of anything but the most basic of gait tests (perhaps, when
used as a outcome measure, it shouldn't be called analysis at all). Surely,
an outcome measure must have simplicity on its side. The problem with
traditional cga is that it gives one so much data that one is able to be
quite selective.

The use of of cga in prosthetics is appealing, naturally. Dealing with
predictable mechanical items must be a joy, and of course cga lends itself
to detrministically-based analysis with the number of DOF markedly reduced.
The clinical rationale is also very clear in this area.
The clinical reasoning for the use of orthoses seems to me, in most
circumstances, to be less clear with the potential for doing harm quite
high. Gait analysis may show  you "improvement" by normalisation of a gait
pattern, but how important is normalisation in improving function or
preventing long term deformity. Any thoughts?

I have been working in gait for only 3 years but I'm already  a little
depressed. CGA promises so much but seems to deliver a lot less. Contrary to
what a lot of bioengineers think, the real problems with CGA are not
technical, they are clinical. We get good(ish) data but unfortunately we
don't use it very well. Where CGA does have a role is in teasing out a
comprehensive understanding of the conditions of our subjects, but how long
are the Financial gods going to wait for cga to become a really useful
engine in decision-making? So Richard, strike while the iron is hot. Make
your address to the Federation using examples from CP, spina bifida, and
amputation for tomorrow your substantial analytical skills may be better
employed elsewhere.


Adam
Adam Shortland PhD,
One Small Step Gait Laboratory,
Guy's Hospital
LONDON
UK

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