therapeutic hosiery oct 2008 cme

7/30/2019 Therapeutic Hosiery Oct 2008 CME

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( n ow k n ow n a s t h er a pe u ti chosiery) have evolved to becomean important comfort item withpotential for significant medical

Continued on page 126

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OCTOBER 2008 PODIATRY MANAGEMENTwww.podiatrym.com 125

Continuing

MedicalEducation

Objectives

1) To review research rele-vant to clinical benefits of ther-apeutic hosiery.

2) To review the role of pres-sure and shear reduction pro-vided by specialized hosieryproducts.

3) To review sock fiber tech-

nologies with specific recom-mendations for use in thera-peutic hosiery.

4) To present newer socktechnologies which have anti-microbial benefits, skin hydra-tion benefits and improved cu-taneous circulation benefits.

5) To designate specific pa-

tient populations who wouldbenefit from regular use oftherapeutic hosiery.

of function and user benefit: theywere universally worn, yet rankedlowest on the scale of importancei n t er ms o f q ua li ty o f l if ebenefits.1 Today, specialized socks

TherapeuticHosiery:An Essential

Component ofFootwear for thePathologic Foot

By Douglas H. Richie Jr., DPM

IntroductionThirty years ago, socks had the

same role as underwear in terms

Socks are an important elementin the treatment armamentarium.


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populations with diabetes, arthri-tis, and peripheral vascular dis-ease. For the first time, peer-re-viewed research was published inprestigious medical journals docu-m e n t i n g p o t e n t i a l b e n e f i t s o f hosiery for foot pathologies.

The first study of pressure reliefo f s pe ci al iz ed

p added hosierywas conducted atthe M anc hesterRoyal Infirmaryi n t he U ni te dKingdom.3 Veves,e t a l . m e a s u r e dplantar pressuresin 27 neuropath-i c d i ab e ti c p a -tients while walk-ing in a barefootcondition, whilew ea ri ng t he irown traditionalsocks, and whilewearing paddedThorLo hosiery.Compared to thebarefoot c ondi-tion, the use of conventional socksprovided no significant relief ofplantar pressure. When wearingpadded hosiery, a significant 26%reduction of peak plantar pressure

was recorded. The researchers con-cluded that specialized paddedhosiery could bea useful, accept-a b l e , a n d i n e x -pensive additionto existing meth-ods for protectingt h e i n s e ns i t i vefoot from abnor-mal pressures andloads.

In a s ub se -

quent study,Veves, et al. com-pared the pressurereduction of ex-perimental extra-p added hosierywith padded sports o c k s i n t h e r e -duction of plantarp ressures in p a-

tients with diabetic neuropathy.4

Both styles of socks reduced plantarpressures significantly, althoughthe extra padded socks reducedpressures by 31% compared to val-ues of 17% and 10% pressure reduc-

tion by ThorLo sport socks. Of sig-nificance, the experimental paddedtherapeutic socks continued to pro-vide significant plantar pressure re-duction of 17% after six months ofcontinuous use.

In another study by Veves, etal., the use of experimental extra-

p a d d e d h o s i e r y

w a s s tu d ie d i np at ie nt s w it hr h e u m a t o i darthritis.5 Oftenoverlooked is thef ac t t ha t th erheumatoid footc an develop ex-t re me p la nt arpressures due tor e s t r i c t e d j o i n trange of motion,atrophy of the fatpad, and digitaldeformity. In thisstudy, padded ex-p e r i m e n t a lhosiery was test-ed in 18 patientswith rheumatoid

arthritis compared to the barefootcondition. Significant reduction ofp la nt ar p re ss ur e ( 32 %) w asa ch i ev e d w h en w e ar i ng t h epadded socks compared to bare-

foot walking. In addition, pain re-lief after wearing the padded socksfor three months demonstrated a51% reduction. This was the firststudy published in the literaturedocumenting that padded hosierycould relieve plantar pressures andpain in the rheumatoid foot.

Murray, et al. studied the pa-tient acceptability of extra-paddedThorLo hosiery when worn withextra-depth shoes.6 A group of 86neuropathic diabetic patients were

followed for six months and com-pleted satisfaction questionnairesat three and six months. Evalua-tion scores were good to very goodin 85% of the patients. The re-searchers concluded that the com-fort of padded hosiery could en-c ourage im p roved c om p lianc ewith appropriate footwear for pre-vention of ulceration in patientswith diabetes.

The previous cited studies ofspecialized ThorLo hosiery wereconducted on patients walkingwithout shoes, and using the opti-


126 www.podiatrym.comPODIATRY MANAGEMENT OCTOBER 2008

Hosiery...

benefits. 2 The therap eutichosiery category of footwear is

n o w a $ 2 0 0 m i l l i o n i n d u s t r yw h ic h i s s t i ll i n i t s i n f an c y i nterms of product development andpatient utilization.

This article will review the his-

tory of development of improvedhosiery products for use in specificfoot pathologies. A review of pub-lished research will be provided aswell as a critical analysis of thecurrent state of the art of thera-peutic hosiery. It is clear that bothconsumers and clinicians shouldbe aware of the potential benefitso f t h e r a p e u t i c h o s i e r y . A t t h esame time, the buyers and pre-scribers of these products shouldbe aware that many of the benefitsclaimed by manufacturers of ther-apeutic hosiery are not substanti-ated by valid research. Since thesefootwear products are not underFDA control, misleading market-ing promotion of health benefitsof therapeutic hosiery productshas led to confusion and misun-derstanding.

A review of research of benefitsof specialized socks or hosiery willreveal three primary areas of inter-

est: plantar foot pressure reduction,reduction of friction skin-shear in-juries, and use ofa n t i m i c r o b i a lf ib er s i n s oc kconstruction.

PlantarPressureStudies

The landmarks tu di es d oc u-men tin g th e

p ressure-reliev-ing capability ofs p e c i a l i z e dhosiery productswere sup p ortedb y a n a t hl et i cs oc k c o mp an y( T h o r L o ,Statesville, NC)who had patent-ed a unique padded hosiery designfor sport application. These stud-ies on substantially padded athlet-ic soc ks revealed the p otentialt h e r a p e u t i c e f f e c t s o f h o s i e r yproducts for specialized patient

Continu

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Often overlooked

is the fact that the

rheumatoid foot can

develop extreme

plantar pressures due

to restricted jointrange of motion,

atrophy of the

fat pad, and digital

deformity.

The researchers

concluded that the

comfort of padded

hosiery could

encourage improved

compliance with

appropriate footwear

for prevention of

ulceration in patients

with diabetes.


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layer socks. This verified previousobservations that c otton fibersoc ks c om p ress and lose shap eduring continuous wear comparedto synthetic acrylic fiber socks.

After this study, nearly tenyears passed before any credibler e s e a r c h w a s p u b l i s h e d i n t h em e d i c a l l i t e r a -

t u r e r e g ar d i ngprotective bene-fits of specializedhosiery products.In the meantime,the therap eutichosiery segmentof the footwearindustry under-went exponentialgrowth as manym a n u f a c t u r e r sintroduced prod-u ct s w it h p ro -p o s ed b e n ef i t sf o r p a th o l og i cfeet, particularly the diabetic foot.None of these companies conduct-ed pressure studies or other re-search to validate their marketingclaims, yet usage of these productsgrew at an astronomical rate.

In 2005, Garrow, et al. studied19 patients with diabetes and pe-rip heral neurop athy and c om -

pared a new dou-ble layer sock toordinary socks todeterm ine p res-sure relief in vari-ous areas of thefoot.11 A special-ized double-layerhosiery productprovided a signif-icant 9% reduc-t i o n o f i n - s h o et o t a l f o o t p r e s -

sure compared toordinary super-market socks. Inaddition, a 14%reduction of peakforefoot pressureand 8% increasedsurface area con-tact was achieved

when wearing specialized sockscompared to ordinary socks.

These pressure studies of spe-c ializ ed hosiery p roducts offerpromise, but also provide resultswhich require careful interpreta-tion. While statistically signifi-

c al p edobarograp h to m easureplantar foot pressures. Thus, thesestudies were direct comparisons ofbarefoot vs. socks without the in-fluence of shoes. Flot, et al. werethe first to measure in-shoe plan-tar pressure reduction of padded

socks in the shoes of eight healthysubjects.7 Significant reduction offorefoot plantar pressures werenoted when wearing the paddedsoc ks c om p ared to the c ontrolsocks, although the pressure re-ductions were not uniform acrossthe entire forefoot.

Donaghue, et al. used in-shoepressure measurements to deter-m ine the durability of p addedT h o r L o s o c k s a n d e x t r a d e p t hshoes when worn by 50 patientswith diabetes and high risk feet.8

Significant pressure relief (10.7%)was found with new shoes andpadded socks, compared to cur-rent footwear. After six months ofcontinuous use, no loss of pres-sure reduction was determinedwith use of extra-depth shoes andp added soc ks. The researc hersconcluded that there was signifi-cant initial reduction of plantarfoot pressures when padded socks

were worn withp ro pe r s ho es ,and this protec-tive benefit wasnot lost after sixm onths of c on-tinuous use.

In addition toelevated plantarp r e s s ur e s , s t e ps h o c k h a s b e e nassoc iated witht i ss u e d a ma g e ,

which can causeulceration on thew e i g h t b e a r i n gs u r f a c e s o f t h ef o o t .9 H owarthand Rome stud-ied the shock at-tenuating prop-erties of five dif-ferent sock types on a single sub-ject while walking over a tread-mill.10 Acrylic cushion and woolcushion socks provided signifi-cantly increased shock attenua-tion compared to cotton socks,cotton terry and cotton double

Hosiery... cant, the reduction ofb e t w e e n 1 0 % a n d 3 2 %peak plantar pressure maynot have any influence on therate of ulceration in the diabeticpatient.

Previous studies showing 25-32% reduction of plantar pressure

w ith p ad de d

hosiery were per-form ed withoutshoes, while in-sh oe s tudie ss ho we d mu chl ow er o ve ra llp r e s s u r e r e d u c -tion. While socksa l on e h a ve c a-pacity to reducedamaging forceson the soft tissueof the foot, theirinfluence is lesssignificant thanwith a shoe alone

or a shoe in combination with acustom-molded foot orthosis.

For example, Kastenbauer. etal. found that a 50% reduction ofplantar pressure occurred when di-a b e t i c p a t i e n t s w o r e r u n n i n gshoes with custom-molded footorthoses. 12 However, a follow-upstudy showed that this pressure of

an orthosis/shoe combination willdeteriorate over time, with only a13% reduction of pressure provid-ed at the end of one year.13 Black-w e l l , e t a l . h a v e s h o w n t h a thosiery will show less noticeablepressure reduction when worn inshoes compared to when worn inslippers.14

On the other hand, one couldargue that any pressure reductionin the shoe of a diabetic patientw i t h a h i g h r i s k f o o t i s b e t t e r

than no protection at all. Sincehosiery is an almost mandatoryrequirement of all people wearingclosed shoes, the upgrade to spe-cialized hosiery represents an ac-ceptable, potentially cost-effectivemodification of lifestyle whichcan protect the diabetic, at-riskfoot. Studies have shown that spe-c i a l i z e d h o s i e r y p r o d u c t s c a nmaintain their pressure relief overa period of six months or more,which is more favorable than thats e e n w i t h s h o e s a n d o r t h o s e salone.


Continuing

MedicalEducation

Friction and

shear are two other

major forces which

are recognized to

contribute to the

formation of ulcers

in patients with

diabetes.

While socks

alone have capacity

to reduce damaging

forces on the soft

tissue of the foot,

their influence is less

significant than

with a shoe alone or a

shoe in combination

with a custom-molded

foot orthosis.


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fiber socks, and blister size wasthree-fold larger with the cottonsocks. The runners observed thatthe acrylic fiber socks kept theirfeet drier in a blinded analysis.

The follow-up study repeatedthe original design, but utilizedgeneric sock con-struction, rather

t ha n p ad de dThorLo construc-tion.19 The supe-riority of acrylicfiber socks overcotton fiber socksc o uld no t b ed e m o n s t r a t e dw h e n t h e s o c k swere not padded.The authors con-c luded that thef r i ct i o n r e d uc -tion and wickingcharacteristics ofs o ck s w er e d e -pendent on bothf i b er c o mp o si -tion and construction technique.

Friction blisters are among themost common foot injuries affect-ing the athlete and are a serioust hr ea t o f d is ab il it y i n t hemilitary.20 A study performed on357 military recruits at Parris Is-

land, South Carolina revealed a69% prevalence of blisters duringa four-month period of training.20

Blisters serious enough to warrantmedical evaluation at sick-call oc-curred in 24% of all trainees. An

estimated 5,000basic trainees atLackland AirforceBase were treatedfor friction blis-t e r s d u r i n g o n ecalendar year in

1990.21Three studies

h a v e b e e n p u b -l ishe d b y th eU ni te d S ta te smilitary involv-ing the testing ofsoc k system s to

reduce friction/shear injuries inthe feet. In the study of 357 mili-tary rec ruits, the use of a CoolMax liner with a heavily paddedwool/polypropylene outer socksignificantly reduced blisters com-pared to a single-layer sock (40%vs. 69% frequency).20 When the

Cool Max liner was added to thesingle layer sock, sick call visitswere reduced from 24% to 9%. In1993, another study of 1,079 sol-diers tested five sock systems andblister frequency.22 Synthetic fibersocks significantly outperformed

t he sta nd ar dw oo l soc k .

A d di n g a C o olMax liner signif-ic antly reduc edb l i st e r s. W h e nc o m p a r i n g s i n -gle, extra-thic kp a d de d a c r yl i csoc ks to doublel a y er s o ck s y s-tems, the double-l ay er s ys te msw er e s up er io rpresumably duet o s h i e l d i n g o f t he t er ry l oo pc o n s t r u c t i o na w ay f r om t h esk in an d th e

m o v e m e n t i n t e r f a c e w h i c h i savailable in the double-layer con-struction. Jagoda also affirmed thesuperiority of wearing a liner sockand padded sock, compared to asingle sock system in Marine re-cruits.23

Studies of socks and frictionblisters on the feet suggest thatthe establishment of a movementinterface either within the sock it-self or between the layers of a socksystem will prevent skin injury.Furthermore, reducing the frictionforc e on the skin surfac e itself may be dependent upon the fibercomposition of the sock, wheresynthetic fibers appear to workbest.24

T h e s u pe r i or i t y o f c e r ta i n

fibers for therapeutic hosiery arebased upon certain factors whichrelate to protection from pressureand shear, reduction of moistureon the skin surface, resistance tocompaction, and maintenance ofshape when subjected to moistureand shear.

With regard to moisture man-a g e m e n t o n t h e s u r f a c e o f t h efoot, the term s hydrop hobic ( re pe l m oi st ur e) a nd hy -drophilic (retain moisture) areutilized in describing sock fiberperformance. In general, cotton



Hosiery...

Shear StudiesF r i ct i o n a n d s h e ar a r e t w o

other major forces which are rec-ognized to contribute to the for-mation of ulcers in patients withdiabetes.15

In gait, the human foot strikes

the ground from a tangential atti-tude, rather than a purely verticalorientation. Friction is the activeor static force that acts on the skinwhich resists sliding. During walk-ing, tangential foot strike with theground causes the superficial skinto be subjected to frictional forcewhich then results in skin exfolia-tion and generation of heat. A sec-ondary shear force is the static sit-uation where the fixed foot exertsa horizontal (backwards) motionagainst the deeper tissues duringpush-off, which results in blister-ing and subsequent ulceration ofthe integument.16

Only rec ently have devic esbeen developed to measure footshear in-vivo. Lord and Hosienwere able to detect a 15% reduc-tion in shear beneath the firstmetatarsal head when thin nylonhosiery was compared with a bare-foot condition.17 Other researchers

have relied on a clinical endpointsuch as the formation of frictionblisters to determine the effective-ness of hosiery products to reduceshearing forces acting on the footduring walking and running.

H e r r i n g a n dRic hie wer eam ong the firstto study the ef-fec ts of hosieryf i b er c o mp o s i-t io n a nd c on -

struction on theincidence of fric-t i o n b l i s t e r s i nl o n g - d i s t a n c erunners. The firststudy comparedthe incidence ofb l i s t e r s i n r u n -ners wearing special padded (ThorL o ) s o c k s e i t h e r c o m p o s e d o f 1 00 % c o tt o n f i be r s o r 1 0 0%acrylic fibers.18 This was a longitu-dinal double-blind study of 35long-distanc e runners. Cottonfiber socks were associated withtwice as many blisters as acrylic

Continu

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Friction blisters are

among the most

common foot injuries

affecting the athleteand are a serious

threat of disability in

the military.

Studies of socksand friction blisters

on the feet suggest

that the establishment

of a movement

interface either within

the sock itself or

between the layers of

a sock system will

prevent skin injury.


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the feet, and the fact that cottonsoc ks c an absorb this m oisturewithout becoming saturated.

However, during vigorous ac-tivity, the absorptive capacity ofany sock will bee x ce e de d , a n do n l y a w i c k i n gg ra di en t w il l

allow movementof moisture fromthe foot surfacet o t h e s h o e f o re v a po r a ti o n t othe outside envi-r on me nt . H y-drop hilic fiberss u c h a s c o t t o nhave a 2.4 timesgreater resistancet o mo istur etransport. 30 Thismay be related toa bs or pt io n o f f l u i d a n d s w e l l i n g w i t h i n t h ef i b e r s t h e m s e l v e s . W h e n w e t ,acrylic fibers swell 5% while woolfibers swell 35% and cotton fibersswell 45%.31 Swelling of fibers isrelated also to a loss of shape andconformability to the foot. Cottonsocks tend to bunch and elongatewhen wet, while synthetic fibersoc ks are m ore l ikely to retain

shape, cushion, and resiliency inthese conditions.32

Moisture management is animportant function for therapeu-tic hosiery. The coefficient of fric-tion on the skin surface is signifi-

cantly increasedby moisture.33 In-c reased fric tionc o e f f i c i e n t w i l lresult in greaterrisk of shear in-jury to the skin

o r d ee pe r t is -sues. 34 T h i s b e -comes importantfor patient popu-lations with con-d it io ns o f t hefeet which are ac-

companied by fat pad atrophy,bone prominences, and structuraldeformity. Increased moisture onthe skin surface of feet is associat-ed with greater risk of bacterial,fungal and viral infections.35

However, the primary patientpopulation at risk for skin injuryis the patient with diabetes and

fibers and most wool fibers arec onsidered hydrop hilic , whilesynthetic fibers are hydrophobic.The response of socks to exposureto m oisture is im p ortant fromboth a comfort and clinical stand-point.

Moisture can accumulate inthe shoe of ac tive p eop le fromthree different sources: the footitself, the legs and trunk of theathlete, and the outside environ-ment. The foot contains eccrinesweat glands which are innervat-ed by cholinergic fibers activatedby the sympathetic nervous sys-t e m . T h e p a l m s a n d s o l e s a r eu n i qu e i n h a v i n g t h e h i g h e s tdensity of eccrine sweat glands inthe body: 2000 glands per squarecentimeter, compared to a densi-ty of only 100 glands per squarec e n t i m e t e r i n t h e r e s t o f t h ebody.25

The production of moisturefrom the sweat glands of the feetduring vigorous physical activityis estimated to be as much as 200c.c per hour.26 The production ofmoisture from the remainder ofthe body during exercise can ex-ceed one liter per hour.26 The sum

total of moisture potentially col-lecting in the shoe of an athleteduring exercise will quickly ex-ceed the absorptive capacity ofany sock. Therefore, in order tokeep moisture content at a mini-mal level on thes ur fa ce o f t hefoot during exer-cise, a sock mustmove moistureaway to the shoeupper for evapo-

ration. This pro-cess is known aswicking.27

Cotton fibersare hydrop hilicand absorb threetimes the mois-ture as synthetic ac rylic fiberswhich are commonly used in ath-letic hosiery.28 Once wet, cottonsocks retain moisture and have aten-fold greater drying time com-pared to synthetic fiber socks.29 Insedentary activity, cotton socksmay be preferable to acrylic socks,given the low moisture output of

Hosiery... peripheral neuropathy.Autonom ic neurop athycauses a loss of innervationof the eccrine sweat glands ofthe feet, and sweating becomes

a bs en t. T hu s,c o n c e r n s a b o u tw ick ing an dm o is t u re m a n-

a ge me nt byhosiery worn bythe diabetic pa-t i e n t a r e i r r e l e -va nt . On th eother hand, theresilience, cush-i o n p r o p e r t ie s ,and shear reduc-ing properties ofsynthetic fiberscompared to cot-ton fibers shouldstill be importantfactors in selec-

t i o n o f s o c ks f o r n e u ro p at h i cpatients.

Fiber Recommendations forTherapeutic Hosiery

A review of the medical litera-ture shows a clear superiority ofsynthetic fibers over cotton fibersin providing health benefits forpeople with foot pathology. These

studies have doc um ented thatacrylic fibers and polypropylenefibers can provide better protec-tion from impact, pressure, shear,and moisture accumulation com-pared to cotton fibers. Yet, themedical marketplace continues tofeature diabetic socks composedof cotton fibers. Many authoritiesand professional organizationscontinue to provide consumer in-formation to the general publicw h i c h i n c l u d e s t h e c h o i c e o f

white cotton socks as being pre-ferred for healthy feet.

This underscores a significantproblem for patients with at-riskfeet who seek information andp r o d uc t s t o p r o t ec t t h e i r f e e t .There is no regulation of claimsma de b y ma nu fa ct ur er s o f footwear and foot products sold tothe general public. These productsare sold in retail pharmacies, de-p a r t m en t s t o r e s , h o m e / he a l t hstores and, most importantly, overt h e I n t e r n e t . A v i s i t t o a n y o f these vendor outlets will reveal a


Continuing

MedicalEducation

Once wet,

cotton socks retain

moisture and have a

ten-fold greater drying

time compared to

synthetic fiber socks.

A review of the

medical literatureshows a clear

superiority of synthetic

fibers over cotton

fibers in providing

health benefits for

people with foot

pathology.


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lower extremity pathology. Edemacauses fatigue, nerve entrapment,stasis dermatitis and limited jointrange of motion. Reduction of pe-ripheral edema has potential ben-efit for signific ant num bers of

p eop le over thea g e o f 6 0 . Y e t ,there c ontinues

to be unsubstan-t i a te d c o n ce r nabout the use ofc o m p r e s s i o nstockings for at-risk patient pop-ula tio ns. Atmost, therapeutics o c ks w i l l p r o -vide 20 mmHg ofp ressure, whic hw ou ld n ot o c-clude blood flowi n a n y p at i en t

other than one with severe arterialobstruction.

Indications for TherapeuticHosiery

Most research published onthe clinical benefits of therapeutichosiery has focused on pressurerelief in the diabetic foot. Yet,many other patient populationswould benefit from specialized

hosiery. Plantar p ressure, skins h e a r , a n d p r e s s u r e o v e r b o n ep ro mi n en ce s o cc ur i n m an yhealthy people who subsequentlydevelop hyperkeratosis, bursitisand friction blisters of the skin.Moisture accumulation on the sur-face of the skin of the foot is asso-ciated with increased risk of bacte-rial and viral infection. Moisturewill increase the coefficient of fric-tion on the skin surface, renderingthe foot more vulnerable to blis-

tering and infection.High plantar pressures are seen

i n p a ti e nt s w i th r h e um a to i darthritis as well as healthy patientswith cavus deformity of the feet.Bone pressure, causing risk of skininjury, is seen in severe cases ofhallux abductovalgus deformity aswell as severe claw toe deformity.

Patients with peripheral vascu-lar disease are at risk for skin in-j u r y o f t h e f e e t a n d w o u l d b eprime candidates for interventionwith therapeutic hosiery. Venousinsufficiency also increases therisk of ulceration in the lower ex-

tremity, and specially designedtherapeutic hosiery can protectthe skin of the lower legs and feetwhile providing significant com-pression for relief of peripheraledema.

Finally, patients with general-ized foot pain due to arthritis, fatp a d a t r o p h y a n d b o n e p r o m i -

n e n ce s c a n o b t a i n r e l ie f w i t hpadded hosiery. Elderly patientswith these symptoms should beprescribed specialized hosiery tosupplement footwear designed toprotect the feet and provide painrelief.

Fitting ConsiderationsWhile most podiatric physi-

c i an s a r e a w a re o f t h e i m p or -tance of shoe fit in preventingfoot pathology, few appreciatethe problems in finding hosieryw h i c h p r o p e r l y f i t t h e f o o t o f the p atient. David H iggins*, anoted authority in the design oftherapeutic hosiery, has recom-m ended that the m ost funda-mental and important elementsof a proper therapeutic sock in-clude optimal moisture manage-m e n t m a t e r i a ls , a n t i b a c t er i a lfibers or treatments, and properfit and design. As is true of any

f o o t w e a r d e s i g n e d f o r a t - r i s kfeet, proper fit should be consid-ered above all else.

Most health professionals arenot aware that hosiery products

are not sized specific to foot size:they are designed to span fromthree to four sizes. This leads toinappropriate stretching and thin-ning of the sock padding whenthe larger end of the size range isworn, and leads to bunching andwrinkling when the shorter end ofthe size range is worn.

Currently, most therapeutichosiery manufacturers use a sizing



Hosiery...

p l e t h o r a o f p r o d u c t s a n dremedies for foot conditions

which promise therapeutic bene-fits without any scientific verifica-tion. Consumerscontinue to pur-c h a s e p r o d u c ts

w h i c h h a v e n oestablished bene-f it , a n d w h ic hmay pose signifi-c an t t hr e at t otheir foot health.The new explod-i n g c a t e g o r y o f t h e r a p e u t i chosiery has morep ro d uc ts w i thm i s l e ad i n g a d -v e r ti s in g t h a nany other type offootwear m arketed to p atientswith at-risk feet.

Other Potential Benefits ofTherapeutic Hosiery

There has been recent atten-tion to the potential clinical bene-fit of compression in the upper ofa sock worn by active people. Inp a r t i cu l a r , s o m e o v e r - t h e - ca l f sport socks have enough elastic

compression to aid in venous re-turn of blood flow from the feetand lower legs. Brown and Brownwere the first to show the benefitsof Thor Lo basketball socks in im-proving objective and subjectivemeasures in patients with venousinsufficiency.36 Ali et al. showedthat over-the-calf sport socks withspecially designed uppers for grad-uated compression would reducethe symptoms of delayed muscles o r e n e s s i n m e n a f t e r a 1 0 k m

road run.37 Graduated compressionover-the-calf socks are now usedin p rofessional hoc key and bysome world class distance runners.For many people, especially males,the option to wear athletic-stylesocks to prevent edema of the feetand ankles is preferred over con-ventional compression hosiery.

There are now several thera-peutic hosiery companies provid-ing over-the-c alf knitted soc kswhich offer substantial compres-sion and p otential therapeuticbenefit. Peripheral edema is foundin many patient populations with

Continu

ing

Med

ical E

ducatio

n

The best

therapeutic hosiery

products are sized

to a maximum range

of two shoe sizes.

Patients with

peripheral vascular

disease are at risk

for skin injury of the

feet and would be

prime candidates for

intervention with

therapeutic hosiery.


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New Technologies forTherapeutic Hosiery

The most significant advancein therapeutic hosiery design overthe past ten years has been the in-troduction of antimicrobial ingre-dients. So-called hygienic fibershave become popular in apparel,

bedding, carpet-

ing and hosiery.T he a pp ea l o f this technologyis a perception ofprotection fromi nf ec ti on a ndodor when theseproducts are usedor exposed to hu-mans. This pro-vides far-reac h-ing benefits forthe populations

who utilize therapeutic hosiery.Silver is the first element to be

utilized in hosiery products. Cur-rently available under the brandn a m e X - S t a t i c , s i l ve r t r e at e dfibers have been shown to be bac-teriocidal and fungicidal againstmost common strains of micror-ganisms found on the feet of hu-mans.38 Silver has long been recog-nized for its benefit in treatingwounds and continues to be a fa-

vorite ingredient of newer hight e c h w o u n d d r e s s i n g s . T o d a y ,many companies offer socks com-posed of a small percentage of X-Static treated fibers with p ro-posed anti-microbial benefits forthe user.

A n o t h e re le me nt w it hknown anti-mi-crobial activity iscopper.39,40 Cop-p er s o le s oc ks

utilizing a tech-nology known asCupron have re-c e nt l y b e co m ep o p u l a r i n t h et h e r a p e u t i chosiery market-place.41 The mainm e di c al c l ai mmade by coppersole distributors is the anti-odoreffects of these products.

Other anti-microbial chemicalshave been added to sock fiberswhich are now being utilized intherap eutic hosiery. One long

standard based upon the NationalAssociation of Hosiery Manufac-turers (NAHM) with sizing boardsto verify sock size. These standardsare out-dated by todays standardsand these sizing boards do nottake into account

the variations inc i r c u m f e r e n c ew h i c h o c c u r i ne d e m a t o u s ,pathologic feet.F u r t h e r m o r e ,m os t s oc ks d on o t i n c r e a s e i nwidth or circum-f er en ce a s t hes i ze i n c re a s es .Thus, larger feeta u t o m a t i c a l l yhave more stretching and com-pression of the sock around thefoot.

The best therapeutic hosieryproducts are sized to a maximumr a n g e o f t w o s h o e s i z e s . L o wend hosiery products will offertwo uni-sex sizes from Womenssize 6 to Mens size 13. This pro-vides significant potential for im-proper fit, stretching, and bunch-ing of soc k m aterial inside the

s ho e . P re mi um t h er a pe ut i chosiery offers at least four sizeranges for men and women, withfive ranges being optimal for bothgroups.

A fear of skin injury to the leghas propagated a host of non-binding soc ks whic h ac tuallymay cause more risk to the footthan properly fitted socks whichhave adeq uate elastic fibers tom a in t a in s h a pe a n d s u pp o r t.Newer technologies are now avail-

able in sock manufacturing whichh a v e v i r t u a l l y e l i m i n a t e d t o eseams and constricting bands atthe up p er p ortion of the soc k.Therapeutic hosiery should con-form to the foot with adequateco mp os it io n o f L yc ra o rSpandex . These soc ks will notleave a seam or ridge line at thetop of the sock, yet will maintainshape and resist migration intothe shoe. Instead of non-bind-ing socks, the physician shouldr e co m me n d n o n- b u nc h i ng socks which are elastic, conform-ing and supportive.

Hosiery... s t a nd i ng c o mp o un dused in sock fibers is Mi-croban.42 As with silver andcopper fiber socks, claims havebeen made in the marketing ofsocks containing these anti-micro-bial ingredients, but few of thebenefits have been substantiatedwith clinical studies. While there

may be consumer appeal aboutthe ability of these socks to keepthe skin of the feet free of bacteriaand fungus, no studies have beenpublished showing this positiveclinical outcome. At best, todaysanti-microbial socks will have lesstendency for odor. The develop-ment of socks which can preventinfec tion in the feet rem ains agoal for future research.

New fiber technologies haveshown, in preliminary studies, theability to increase the oxygen con-tent at the skin surface of the feetand lower extremities. Holofiber

i s a n e w p r op r i et a r y p r o d u ctwhic h alters the norm al wave-length of visible light and trans-mits this to the skin of the user inthe form of energy.43 A prelimi-nary study conducted by LawrenceLavery, DPM showed a significantincrease in transcutaneous oxygeno f p a t i e n t s w i t h d i a b e t e s w h o

wore socks composed of Holofiber. A recently published double-blind prospective study showedthat compression stockings withsilver impregnated fibers caused asignificant increase in transcuta-

n eo us o xy ge nperfusion of theskin of the lowerleg compared toregular hosiery.44

Nanotechnol-ogy is a new man-

ufacturing tech-nique whichi mb ed s m ic ro -scopic particles infibers which canbe released on thesurface of the skinfor potential ther-apeutic benefit. An ew pa te nt ed

technology known as the Difoprevsystem (LVM Technolgies, Bologna,Italy) consists of a sock loaded withmicrocapsules containing an activemoisturizer. This system is designed


Continuing

MedicalEducation

New fiber

technologies have

shown, in preliminary

studies, the ability toincrease the oxygen

content at the skin

surface of the feet and

lower extremities.

Other anti-microbial

chemicals have

been added to sock

fibers which are now

being utilized in

therapeutic hosiery.


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when wet, and better resiliencecompared to cotton fibers.

4) Therapeutic hosiery shouldcontain adequate elastic for con-formability, fit, and resistance towrinkling inside of the shoe. Fearsof binding of the upper portion ofthe sock are unwarranted, given the

new technologies to eliminate con-strictive banding at the top-line.

5) Newer anti-microbial sockfiber treatments have great con-s u m e r a p p e a l b u t h a v e y e t t odemonstrate, in published studies,any clinical benefits to the user.Still, addition of this technologyto therapeutic hosiery can only bea positive attribute to improve hy-giene of the product itself.

6 ) T h e r a p e u t i c h o s i e r y c a nhave benefits for patient popula-tions with venous insufficiency,when the upper of the sock coversthe lower leg and has adequatecompression features.

7) Sock-fitting is critical to as-sure benefit of padding and avoid-ance of constriction around keypressure areas. Newer therapeutichosiery p roduc ts are siz ed to a

maximum of two size ranges. I

*[email protected]

Bibliography1 Richie DH. Sock controversy. Phys

Sports Med. 1992: 20(5):55.2 Richie DH. Sports Socks: The role

of hosiery as an essential component offootwear for the active person. Ameri-can Jour Med Sports 2003.5:79-86.

3 Veves A, Masson EA, FernandoDJS, et al. Use of experimental paddedhosiery to reduce abnormal foot pres-sures in diabetic neuropathy. DiabetesCare. 1989;12:653-655.

4 Veves A, Masson E A, FernandoDJs, et al. Studies of experimentalosieryin diabetic neuropathic patienetswith high foot pressures. Diabet Med.1990: 7: 324-326.

5 Veves A, Hay EM, Boulton AJM.The use of specially padded hosiery inthe painful rheumatoid foot. Foot 1992;1: 175-177.

6 Murray HJ, Veves A, Young MJ,Richie DH, Boulton AJM. Role of experi-

mental socks in the care of the high-riskdiabetic foot. A multicenter patientevaluation study. Diabetes Care. 1993;16: 1190-1192,


Hosiery...

to continuously hydrate theskin of the foot of the patient

with diabetes and autonomic neu-ropathy, thus reducing cracking,fissuring and hyperkeratosis. A re-cently published prospective con-trolled study showed that this nan-

otechnology-designed, hydratingsock system caused significant im-provement of skin health in pa-tients with diabetes.45 The authorsspeculated that this system couldbe an additional preventive mea-sure for ulceration of the feet of pa-tients with diabetes.

Summary andRecommendations

The therapeutic hosiery markethas grown exponentially over thepast ten years, but very little re-search has been published relativeto these products after the initialpressure-relief studies were conduct-ed by ThorLo in the early 1990s. Asa result, most of the claims made bytherapeutic hosiery companies arenot substantiated by clinical studies.These claims include non-bindingeffects, anti-microbial effects, andskin protection benefits.

Based upon previous published

research and current technologiesavailable in sock construction, thefollowing recommendations can bemade for the podiatric physicianwho prescribes therapeutic hosiery:

1) The most credible researchon clinical benefits of therapeutichosiery has focused on plantarpressure relief. The hosiery prod-ucts showing significant benefitw e r e c o n st r u ct e d w i t h d e n sepadding under the heel and fore-

foot areas of the foot.

2) Shearing injury to the skinof the foot has been speculated tobe m ore im p ortant than direc tpressure. Double sock systems andheavily padded socks have showndocumented benefit in reducingskin shear injuries of the foot.

3) Synthetic fiber socks are pre-ferred to natural cotton fiber socksfor use by patients with patholog-ic feet. Synthetic fibers offer supe-rior moisture management, betterresistance to shape deformation

Continu

ing

Med

ical E

ducatio

n7 Flot S, Hill V, Yamada W, et al.

The effect of padded hosiery in reducingforefoot plantar pressures. Lower Ex-tremity. 1995;2:201-205.

8 Donaghue VM, Sarnow MR, GuiriniJM, et al. Longitudinal in-shoe foot pres-sure relief achieved by specially designedfootwear in high risk diabetic patients.Diabetes Res Clin Pract. 1996;31:109-114

9 Whittle MW: Generation and at-

tenuation of transient impulsive forcesbeneath the foot: a review. Gait Posture10: 264-275, 1999.

10 Howarth SJ, Rome K. A short-term study of shock-attenuation in dif-ferent sock types. Foot 1996; 6: 5-9.

11 Garrow AP, van Schie CHM, Boul-ton AJM. Efficacy of multilayeredhosiery in reducing in-shoe plantar pres-sure in high risk patients with diabetes.Diabetes Care 2005, 28: 2001-2006.

12 Kastenbauer T, Sokol G, AuingerM, Irsigler K: Running shoes for relief ofplantar pressure in diabetic patients. Di-abet Med 15: 518-522, 1998.

13 Lobmann R, Kayser R, Kasten G,Kasten U et al: Effects of preventativefootwear on foot pressure as determined bypedobarography in diabetic patients: aprospective study. Diabet Med 18: 314-319.

14 Blackwell B, Aldridge R, Jacob S: Acomparison of plantar pressure in pa-tients with diabetic foot ulcers using dif-f e r en t h o si e r y. I n t J L o w E x t r e mWounds 1: 174-178, 2002.

15 Boulton AM: Pressure and the dia-betic foot: clinical science and offloadingtechniques. Am J Surg 187: S17-S24, 2004.

16 Gere JM, Timoshenko SP: Me-chanics of Materials. 2nd ed. Boston,PWS Engineering, 1990.

17 Lord M, Hosein R: A study of in-shoe plantar shear in patients with dia-betic neuropathy. Clin Biomech 15:278-283, 2000.

18 Herring KH, Richie DH. Frictionblisters and sock fiber composition: adouble blind study. J Am Podiatr MedAssoc. 1990;80:63-71.

19 Herring KH, Richie DH. Compari-son of cotton and acrylic socks using ageneric cushion sole design for runners. JAm Podiatr Med Assoc. 1993;83:515-522.

20 Knapik JJ, Hamlet MP, ThompsonKJ: Influence of boot-sock systems on fre-quency and severity of foot blisters. Mi-latary Medicine 161 (10): 594-598, 1996.

21 Gackstetter G, Shrifter J: Injuryreduction sock study. Epidemiology Di-vision, Lackland Airf Force Base, 1994.

22 Robertson TW, Christopherson MS.Improved sock system customer test.Ligget, Ca: Fort Hunter, US Army Test andExperimentation Command Center: 1994.

23 Jagoda A, Madden H, Hinson C. A

friction blister prevention study in ap o pu l a ti o n o f m a ri n e s. M i l M e d .1981;146:42-55.



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Continuing

MedicalEducation

24 Sanders JE, Greve JM, Mitchell SB, et al. Material propertiesof commonly used interface materials and their static coefficientsof friction with skin and socks. J Rehabil Res Dev. 1998;35:161-176

25 Kuno Y. Human Perspiration. Springfield, IL: C.C.Thomas: 1956: 1-65.

26 Grice, K. Sweat glands and abnormalities of their function.In: Marks R, Sammon PD, eds. Dermatology. Vol 6. New York,NY: Appleton-Century-Crofts; 1977:5-68.

27 Farnworth B: A numerical model of the combined diffu-sion of heat and water vapor through clothing. Tex Res J 1986;56: 653-65.

28 Product Knowledge Center for High Performance Fibers,Apparel and Gear. The Acrylic council, Inc., 1285 Avenue of theAmericas, 35th Floor, New York, NY, 10019.

29 Euler RD. Creating comfort socks for the U.S. consumer.Knitting Times. 1985; 54:47.

30 Harris M. Handbook of Textile fibers. Washington,DC:Harris Research Laboratory, Inc; 1954: 173-189.

31 Physical Testing Laboratory: Moisture absorbancy andtransport of cotton versus acrylic half hose, Monsanto TextilesCompany, Decatur, AL, 1988.

32 Textile Research Laboratory: High bulk Orlon: The bestyarn for athletic socks, Progress Report, E.I. Du Pont De Nemours& Company, Inc, Wilmington, De, 1980.

33 Naylor PE. Experimental friction blisters. Br J Dermatol.1955;67:327-335.

34 Sulzberger MD, Cortese TA, Fishman L, et al. Studies onblisters produced by friction. I. Results of linear rubbing andtwisting techniques. J Invest Dermatol. 1966;47:456-463.

35 Levine N. Dermatologic aspects of sports medicine. J AmAcad Dermatol. 1980;3:415-423.

36 Brown JR, Brown AM. Nonprescription, padded,lightweight support socks in the treatment of mild to moderatelower extremity venous insufficiency. JAOA, 1995; 95:173-181.

37 Ali A, Caine MP, Snow BG. Graduated compression stock-ings: physiological and perceptual responses during and after ex-ercise. J Sports Sci 2007, 25: 413-419.

38 www.noblebiomaterials.com39 Grzybowski, J. and E. A. Trafny. 1999. Antimicrobial prop-

erties of copper-coated electroconductive polyester fibers.Polim.Med. 29:27-33.

40 o Borkow, G., and Gabbay, J. (2005) Copper as a biocidaltool. Current Medicinal Chemistry 12(18): 2163-75.

41 www.cupron.com42 www.microban.com43 www.holofiber.com44 Jaccard Y, Singer E, Degischer S, Imfeld S et al. Effect of sil-

ver-threads-containing compression stockings on the cutaneousmicrocirculation: a double-blind, randomized cross-over study.Clin Hemorheol Microcirc. 2007: 36 (1): 65-73.

45 E. Banchellini, S. Macchiarini, V. Dini, L. Rizzo, A. Tedeschi, A.Scatena, C., Goretti, F.Campi, M. Romanelliand A.PiaggesiUse ofNanotechnology-De-signed Footsock in theManagement of Preul-cerative Conditions inthe Diabetic Foot: Re-sults of a Single, BlindRandomized StudyVolume 7 Number 2

June 2008 page 82-87

in The InternationalJournal of Lower Ex-tremity Wounds, SAGEPublicationsUSA.

Hosiery...

1) Relief of plantar pressure with

padded hosiery has shown a reduction ashigh as _______ when compared to going

barefoot.

A) 10%

B) 20%

C) 30%

D) 80%

2) Relief of plantar pressure, inside of the

shoe, provided by padded hosiery, can be

expected on the order of:

A) 1%

B) 2%

C) 3%

D) 10%

3) Skin shear can occur during walking gait,

as a result of:

A) Plantar pressure

B) Tangential attitude of foot strike

C) Unequal leg length

D) Neuropathy

4) Friction blisters of the feet can be re-

duced by socks with:

A) Acrylic fibers

B) Cotton fibers

C) Thin padding

D) Over-the-calf design

5) Studies on marching soldiers demon-

strated significant reduction of blisters of

the feet when wearing:

A) Cotton socks

B) Gore-Tex socks

C) Copper sole socks

D) Double sock systems

6) Over-the-calf athletic socks can:

A) Reduce symptoms of venous insuffi-

ciency

See instructions and answer sheeton pages 200-202.


E X A M I N A T I O N

Dr. Richie is an

Adjunct Associ-

ate Clinical Pro-

fessor in the De-

partment of Ap-

p li ed B io me -

chanics at the

C a l i f o r n i a

School of Podi-

atric Medicine.

He is a member

of the American Academy of PodiatricPractice Management and a past presi-

dent of the American Academy of Podi-

atric Sports Medicine.


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Continu

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n

B) Rheumatioid arthritis

C) Hallux valgus

D) All of the above

12) All of the following are im-

portant characteristics of proper

therapeutic hosiery EXCEPT:

A) Padding

B) Conforming fit

C) Moisture management

D) One size fits all

13) The following are used asanti-microbial additives for ther-

apeutic hosiery EXCEPT:

A) Copper

B) Silver

C) Microban

D) Aluminum

14) Anti-microbial fibers in thera-

peutic socks can best be expect-

ed to:

A) Prevent ulceration

B) Prevent skin infection

C) Prevent fungus toenail

infection

D) Prevent odor in the

socks

15) Friction blisters of the feet

represent a classicA) Shearing injury of the skin

B) Ischemic injury of the skin

C) Fungus infection

D) Viral infection

16) Increased moisture content

on the skin of the feet is associat-

ed with all of the following

EXCEPT:

A) Increased coefficient of

friction

B) Heal ulcers

C) Reduce bacteria

D) Prevent Achilles injuries

7) Therapeutic socks may not be

sized:

A) According to exact foot

size

B) According to circumfer-

ence of the foot

C) According to modern foot

measuring technique

D) All of the above

8) Cotton fiber socks

A) Absorb water better than

acrylic

B) Swell with water absorp-

tion

C) Release moisture slowly

compared to acrylic

D) All of the above

9) Wicking describes the ability

of a sock fiber to:

A) Absorb moisture

B) Repel moisture

C) Move moisture along a

gradient

D) Attract heat

10) In terms of performance fortherapeutic hosiery, synthetic

fibers perform best in terms of:

A) Moisture management

B) Resistance to compaction

C) Wicking

D) All of the above

11) Reduction of shear and plan-

tar pressure are important for

patients with:

A) Diabetes

E X A M I N A T I O N(contd)

SEE INSTRUCTIONS

AND ANSWER SHEETON PAGES 200-202.

B) Risk of bacterial infection

C) Risk of viral infection

D) Peripheral edema

17) Diabetic neuropathy is asso-

ciated with:

A) Hyperhydrosis

B) Anhydrosis

C) Spasiticy

D) Clonus

18) Padding in hosiery can be

beneficial to patients with all ofthe following EXCEPT:

A) Cavus foot deformity

B) Rheumatioid foot deformity

C) Prominent plantar

metatarsal head

D) All of the above

19) Therapeutic hosiery products:

A) Are FDA-controlled

B) Promote only scientific

proven clinical benefits

C) Have potential for signifi-

cant patient benefit

D) Are sized exactly to

matching shoe size

20) The most important clinical

benefit of therapeutic hosiery, as

documented by published medi-cal research, is

A) Relief of plantar pressures

B) Non-binding relief

C) Prevention of infection

D) Prevention of ulceration

therapeutic hosiery oct 2008 cme

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