ogy in its wake. The facts are thatthe foot pronates and supinates tovarying degrees during a gait cycleand correcting abnormal biome-chanics is the challenge. No ma-

chine or computer can tell you ex-actly how much to correct a pa-tient, but technology can guideyou where to correct gait.

We have considerable controlover the kinetic chain and muscu-loskeletal system through the feet.With shoes, wedges, plates and liftswe can aid foot function, improveproper timing, ease shock and im-proving balance. To do this weneed two sets of data, establishnorms and patient values. GaitScangives you both. Touchstones like“arthritis” are useful to explaincomplex conceptslike repetitive mi-crotrauma and itsrelation to knee,hip and backpain; followingup with diagnos-tic ultrasound im-ages or asking thepatient to feeljoint wear arealso effectivecommunicationtools, but, to me,nothing says itlike the TOGGaitScan, withit’s color pictures,charts, numbers and graphs.

I liken the job of podiatrist spe-cializing in biomechanics to that ofan architect, with the additionalcomplications/challenges of pur-poseful motion. Building requirescreating a structure on a founda-tion under the influence of forces,

By Dr. Jay Segel

For nearly 25 years, I have beena podiatrist on Martha’s Vineyard.For this foot doctor, the visualcombination of summer activi-ties, take-out food, shorts andsandals automatically triggersthe occupational hazard of aworking lunch. Here I am withmy wife, sitting on the board-walk at the Oak Bluffs harbor, myface at knee height, watching theparade of tourists and neighborspronating or supinating by withtheir adductory twists and early

heel-offs. Observing short limbsyndrome, ataxia and antalgic gaitpatterns day after day has left mewith an acute sense of the need forpublic and patient education inbiomechanics.

I call it the Quality of Life lec-ture, which is based on the premisethat if people knew the health costof the way they walk, they wouldwant to fix it. What’s needed is forthe patient to understand bothwhat is going on and the fact thatgait is fixable to a large extent. Tobe a “Quality of Life” podiatrist,perform a gait analysis and a physi-cal exam and then create a treat-ment plan to deal with the etiologyof the gait problem and the pathol-

loads, resilience, malleability,shear, and decay. Making an or-thotic requires all of the above onan imperfect platform while deal-ing with triplane motions, ground

force reaction and momentarms. The more pertinent infor-mation I can get about theloaded musculoskeletal struc-ture, static and dynamic, themore success I’ll have in weight

redistribution, controlling motionand establishing appropriate eventtiming with the master plan of di-minishing micro trauma andpathology. So, in other words, wehave to build a skyscraper on anunsteady footing that moves, anddiagnostic tools like the GaitScanhelp tremendously by addingquantitfication to your qualitativegait analysis and provide informa-tion not otherwise “seeable”.

I have always been a fan of gaittechnology such that shortly aftergraduation I purchased Langer’s

Electrodynagram,which I used dur-ing my junioryear for researchand developmentof a strappingtechnique. Bring-ing this technolo-gy to the officeand patient carewas awkward inmany ways andeventually fell bythe wayside. Itwas many yearsbefore I found acomputerized gaitanalysis system

that was powerful, reproducibleand practical! In short, I can see itmakes me a better doc and the pa-tients “get it.”

What Is This Thing?GaitScan is the product of

Canada’s The Orthotic Group.

142 www.podiatrym.comPODIATRY MANAGEMENT • SEPTEMBER 2008

What’s needed is for

the patient to

understand both what

is going on and the

fact that gait is fixable

to a large extent.

TOG’s GaitScan™: For Powerful, Reproducible andPractical Computerized Gait Analysis

Circle #191

Building requires

creating a structure on

a foundation under

the influence of forces,

loads, resilience,

malleability, shear,

and decay.

P R O F I L E S I N P O D I A T R I C B I O M E C H A N I C SP R O F I L E S I N P O D I A T R I C B I O M E C H A N I C S

SEPTEMBER 2008 • PODIATRY MANAGEMENTwww.podiatrym.com 143

• Balance, posture, hypermobil-ity and biomechanical anomalies

• Areas at risk for ulceration

How Do I Use This Thing?Begin GaitScan diagnostics with

the “Static Test.” With the patientin bare feet, ask them to stand di-rectly onto the center of the plate(after data entry) and settle intotheir “normal” stance. The feet aredisplayed in colors ranging from

They report over 1,500 inuse by healthcare practition-ers. Specifically, the unit isan integrated hard-ware/software pressure andtiming system that workswith the computer for com-parative and quantitativegait analysis. Released onJune 17th 2008, the latestGaitScan software is update2.3. It consists mainly of up-dated product informationand Microsoft WindowsVista compatibility. Thehardware is a plate whosedimensions are 40 inches by15 inches and houses 4096sensors. In dynamic mode itreports data at 300 framesper second, providing overone million data points foranalysis. The polymer plateinterfaces with the comput-er through a standard USB2port.

Information generatedby GaitScan includes:

• Static plantar pressures• Asymmetry with quan-

titative left/right proxi-mal/distal, medial/lateral

• Dynamic segmentalloading with norms

• Onset, peak, off-load-ing and duration on 14plantar surfaces

• Phases of gait measure-ments with comparisons toestablished norms

• Overall impulse in percentagewith comparisons to norms

• Multicolored gait and pressuregraphics 2D/3D (Figure 1)

• Shock absorption/groundforce reaction at the heel

• Pronatory charts, rear-foot/whole foot, right/left

• Foot abduction/adductioncompared to plum line

• Quantitative gait speedsleft/right

black, representing anabsence of pressure, toblue, yellow, green,and red, highlightingincreased pressure re-spectively. This is agreat test for diabeticswith histories of ulcersor calluses as it pin-points areas to be off-loaded with deviceslike orthotics. After sav-ing the data,the feet aredisplayed in the afore-mentioned colors withquadrant pressures rep-resented as percentagesof 100%, i.e., 28% leftrear foot to midfoot,32% left midfoot totoes, 19% right rearfoot to midfoot, and21% right midfoot totoes. When you pressthe print button andselect the static option,a similar display willappear superimposedagainst a plumb line,giving you overallleft/right pressures asthe aforementioned leftfoot bears 60% whilethe right bears 40%.

There are 2 differenttypes of dynamicexams, walking andsquatting. The squattest is most useful inobserving knee devia-

tion on single stance loading or forproximal to distal loading fordancers and folks with forefootpathology, but the money shot formost podiatric situations is thewalking test. (Figure 2) To get themost representative walking test, ithas been suggested that the patientneeds to take three steps beforeplate strike and three after. Ask thepatient if that felt like a normalwalk to them. Also observe the foot

Circle #191

TOG’s GaitScan...

Figure 1.

Figure 2.

P R O F I L E S I N P O D I A T R I C B I O M E C H A N I C SP R O F I L E S I N P O D I A T R I C B I O M E C H A N I C S

now and later. This is a good timeto begin or continue an ongoingdiscussion about proper footwearand orthoses if appropriate. Underthe print function you will findtwo other important reports, theaforementioned static report, andthe dynamic report.

The dynamic report is an ex-pression of the walking test andconsists of three parts. The firstpart is the numbers expressed aspercentages of gait cycle; start

strike—often I’ll suggestto the patient that “itseemed like you shortstepped”, or “you lookedlike you were crossingover.” It’s easy to redo thetest and I’ll often do justthat even with a per-ceived “good test” to veri-fy the results. I have al-ways been impressed withthe relatively consistentresults of the TOGGaitScan. It’s importantto point out GaitScanmay misrepresent the leftfoot as right in “automat-ic” mode in patients withsevere deformities. Forthese people you musttoggle on the “manual”mode and assign left orright values for thescanned foot.

What Do We Get Outof This Thing?

Once I’ve obtainedand saved “good scans”, Igenerate patient reports.While still in the walkingmode, select the prona-tion/supination buttonto display both feet inlinear format, showingrear foot and whole footcontact position, andmotion (supina-tion/pronation) througha gait cycle. (Figure 3) This is a con-densed view of foot function,shock absorption, biomechanicaldeformity, timing and asymmetry.Now use the comparison button todisplay the patient’s dynamic com-posite foot graph on the left side ofthe computer and “optimal” scanadjacent. This is a very useful edu-cational tool for communicatingwith patients about how their feetstack up against the model andwhat it means to their health, both

times, end times, peakpressures and impulse for14 plantar surface points,lateral heel, medial heeland submetatarsal headsone through five for bothfeet. This report alsodemonstrates sequentialloading and phases of gaitwhere a doctor might seevalues suggesting biome-chanical, functionaland/or acquired deformi-ties such as forefoot val-gus, rocker bottom footor equinus. Aberrantreadings are highlightedas follows; green is “nor-mal”, red indicates valuesrelatively too high, toolong, or too late, andblue values are relativelytoo low, too brief or tooearly. Remember, valuesgenerated from running,squatting, lifting or oth-erwise nonstandardwalking, list no estab-lished norms so valuesdon’t necessarily meananything. The data findsits value in comparisonright to left and otheradvanced analysis avail-able in continuing medi-cal education programsoffered by The OrthoticGroup (TOG). They alsooffer a “no fee” consult-

ing service. I routinely call thebiomechanics department to dis-cuss patient data and its practicalapplications in making better or-thotics.

The second part is a multicol-ored wave display of the varioussegments of each foot expressed asforce, vertically, and time, horizon-tally. (Figure 4). This is anotherwonderful graph for patient educa-tion. For instance, we can explainthat heel-off should occur at about

144 www.podiatrym.comPODIATRY MANAGEMENT • SEPTEMBER 2008

Circle #191

TOG’s GaitScan...

Figure 4.

Figure 3.

P R O F I L E S I N P O D I A T R I C B I O M E C H A N I C SP R O F I L E S I N P O D I A T R I C B I O M E C H A N I C S

SEPTEMBER 2008 • PODIATRY MANAGEMENTwww.podiatrym.com 145

frame of data obtained at 300 framesper second, beginning at heel strikeand continuing through toe-off. Thisis great for show-ing ground forcereaction, MedialLongitudinal Archcollapse, andhitches in gait dueto instability orpain. The abovegait characteristicscan be spotted byobserving the gaitline which shouldbegin with a lateralheel strike fol-lowed by a smallcurl demonstratingground force ab-sorption, then animmediate heel ev-ersion, resupina-tion (laterallymoving gait line),then as the foot approaches mid-stance, the gently arcing line headsmedially till heel-off. Then, movinginto the terminal phase of gait, theline continues medial, shifting thefoot from its accommodative “loosebag of bones” state to that of a rigidlever for effective propulsion. In part,this is the same graphic as in the com-parison view but here, a foot can beisolated (right or left) and played backin a larger cineloop for your commen-tary on the subject’s gait in real time.This graphic can be viewed in both 2Dand 3D modes. The 2D mode is greatfor overall linear function and where-as the 3D mode demonstrates loadingand pressure data in a more accessibleand dramatic format. For a visual of aGaitScan cineloop, hit my website atsegelpodiatry.com. After testing, Ioften give copies of the static exam,dynamic report, pronation/supinationgraph, and comparison views withboth subjects feet and “optimal” scansto share with friends, family andhealthcare professionals.

55% of gait cycle. One can clearlyobserve the graph and note whenheel pressure is gone. Just as latepeaking pressures at the ball of thefoot may indicate pronation, bywatching areas off-load we mightfind evidence of deformities likefunctional hallux limitus in a latepeaking and sharply declining hal-lux line. To the right of the wavesare small composite displays of thewalking test which serve as a key tothis color coded linear model and acheck of the data. By a “check ofthe data” I’m referring to a phe-nomenon that can occur by thecombination of segments diplayedas one colored line. I’ve observedthis when the “blue” hallux regionerroneously includes the adjacentmetatarsal making that particulardata line suspect. Rerunning thedynamic scan usually fixes thisanomaly.

The third part of the walking re-port is a large multicolored pictogramof the aforementioned composite

wave graph key but the colors hereinrepresent pressure grades rather thanplantar surfaces. It uses the same col-ors as the static exam but if you lookcarefully, you’ll note black dots strungtogether indicating gait progressionand pattern. Each dot represents one

When Do I Use This Thing?GaitScan is a biomechanical di-

agnostic tool. I use it for patientspresenting withcomplaints relat-ed to the follow-ing:

• Wa lk ing ,running, athlet-ics, working, stand-ing andbalance

• Neurologicaldisorders and/orataxia, Parkinson’sDisease

• Asymmetry,Short Limb Syn-drome and con-tractures

• Musculo-skeletal patholo-gies, Plantar Fasci-itis, Heel SpurSyndrome, Scolio-sis

• Biomechanical deformities;congenital Coxa Vara, acquiredHallux Valgus

• Macrotrauma, fractures, joint re-placements and chronic ankle sprainers

• Microtrauma, overuse, HalluxLimitus, arthritis

• Pressure issues, Diabetes Mellitus• Orthoses and brace wearersWith its easy portability, I have

brought it to health fairs andschools for public education. Usingthis technology to raise awarenessin young people to the dangers ofabnormal gait and the ability topredict and prevent problems isperhaps the most important aspectof GaitScan. Maybe the next time Ifind myself eating at the Oak Bluffswaterfront, eyes besieged by theimpending doom to barefootbeachgoers, I’ll bring my GaitScanand make it a true working lunch.

For more information call 800-551-3008, visit www.GaitScan.com,or circle #191 on the reader servicecard.

Circle #191

TOG’s GaitScan...

This is a very useful

educational tool for

communicating with

patients about how

their feet stack up

against the model and

what it means to their

health, both now

and later.

After testing, I often

give copies of the static

exam, dynamic report,

pronation/supination

graph, and

comparison views with

both subjects’ feet and

“optimal” scans to

share with friends,

family and healthcare

professionals.

P R O F I L E S I N P O D I A T R I C B I O M E C H A N I C SP R O F I L E S I N P O D I A T R I C B I O M E C H A N I C S