58

ABSTRACTS OF RECENT ARTICLESThe following articles have been abstracted by Joan E . Edelstein, R .P .T .,who is a Senior Research Scientist, New York University Post-GraduateMedical School, Prosthetics and Orthotics, 317 East 34th Street, New York,N.Y.10O10.

For this issue of the Journal, Joan Edelstein hasselected 22 articles for abstraction and two booksfor review. You will find 22 abstracts which fall intothe following general categories:

Gait analysis 4Amputation 3Applications ofFEB2Sp\na!/uen/ioal orthotica3Control ofepaoticity1Lower limb orthntice4Lower limb prosthetics 2Upper limb orthotice1General 2

The articles have been drawn from the followingjournals:

American Journal of Physical Medicine 1Prosthetics and Orthotics International 5Journal of Bionneohanioe1Medical and Biological Engineering and Computing 2Scandinavian Journal of Rehabilitation Medicine 2Spine 1Physical Therapy 3Archives of Physical Medicine and Rehabilitation 6/\otaOhhopaedicaScandinow!oa1

One of the books reviewed in this issue is a guide tothe selection and application of controls for assistivedevices; the other is a resource manual on seatingfor children with cerebral palsy . Reviews follow thepresentation of abstracts.

Advantages of eSimpYe Contact Switch for Human Loco-motion: Frederick Patterson, Linda Gorman, and MaryWetzel (Department of Psychology, University of Arizona,Tucson, Arizona) American Journal of Physical Medicine63:11-17, February 1984.

A simple foot contact switch was designed and testedfor eevenal years . The switch excludes the effect uponmovement imposed by different footwear, and allowsdirect comparison of barefoot walking with walking in ashoe . The switch has operated successfully for subjects ofmany sizes and weights who performed different tasks ona motor-driven treadmill . The switch is made from com-mercially available foam insole or shoe insert 4 mm thick.Double-thick heel-shaped pads are cut from the insole,

then a 1 cm square is cut through the center of each pad.The electrical conduction portion consists of two strips ofmetallic tape (burglar alarm window foil), each 14 cm long.The strips are secured to the pads with double-sidedadhesive tape reinforced with electrical tape, so that thestrips are separated by the width of the double pad . Thecompleted switch is held to the foot with elastic adhesivebandage, and is connected to an electronic recordinginstrument by attaching the free ends of the foil strips towires fastened to the subject's leg with Velcro.

Time elapsed between heel touchdown and liftoff asmeasured by the footswitch (and as determined frommovie films) was compared with subjects wearing a sandaland then walking with the insole foot switch . Differencesin time recordings were attributed to different movementsof the feet. One subject touched down with the heelappreciably in advance of the up-thrust ball ; the heel andball moved backward and upward until a lingering liftoffwas seen for the toes . Another individual walked in a moreflat-footed fashion without toe lingering.

The small size of the insole device permits its use torecord contact by other portions of the foot in addition tothe heel . The switch eliminates distortion of stance dura-tion iimingattribu\ab\m\000nven\iona!ahoea.

Amputation Revisited: G. Murdoch (Limb Fitting Centre,Dundee, Scotland) Prosthetics and Orthotics Interna-tional

In ancient times, amputation usually resulted fromgangrene or trauma, sometimes associated with hKualsacrifice, punishment, or ergot poisoning . Today, the carand leprosy are common causes but in Europe and NorthAmerica most amputations are performed because ofvascular disease . Many patients are now rehabilitated,primarily because skin perfusion pressure measurements,Doppler ultrasound, and thermography enable predictionof wound healing . In trauma, all viable tissue should beconserved. Chemotherapy permits amputations throughbone affected byoet000arnoma if the site is 10 cm abovethe most proximal area of bone reaction . Radical localresection and internal prosthetic replacements may obviatesome amputations . Congenital absence of the fibula isbest treated by foot ablation at 10 months . Ambroise Parein the sixteenth century was the first to choose a site wellabove the gangrenous area at a ievol suitable for fittingwith a prosthesis . Today, site selection involves pathology,anatomy at the proposed level, and what prostheses areavailable.

The preoperative phase should include explanation of

59

Journal of Rehabilitation Research and Development Vol . 22Nu1 1985

the operation, phantom phenomenon, and the rehabilitationprogram. Spinal anesthesia ensures no pain for 1-2 hours,with less confusion and fewer problems with hypotensionand chest complaints . Ca!ouu in A.D. 25 used a rasp tosmooth rough bone margins . Lister's antisepsis paved theway for modern tissue management . The higher the ratioof the base to the length of the flap the better the chanceof healing . Muscle stabilization yields better blood supplyto the wound . In the Peloponnesian War, the stump wascauterized and covered with tar . Today a rigid cast andcontrolled environment prevent edema.

Above-knee amputation should be 12-13 cm above theknee, where most adductors have been inserted and themajor neurovascular bundles have arrived at their destina-tion . Myoplasty ensures a stump of smooth contours andstable shape . Knee dio rti !at\on with medial and lateralflaps permits true end-bearing, with good proprioceptionand rotational stability . A posterior flap should be used forbelow-knee amputation in dysvascular patients . 0a1e*myop!aetybetweenthe tibia and fibula is very satisfactory.Malleolar projections may be removed from the Symestump, provided the level of amputation is as was describedoriginally . Pirogoff amputation provides excellent end-bearing.

During the middle ages prostheses were mainly intendedto conceal the amputation of soldiers on horseback.Modern prostheses are designed with increased under-standing of biomechanics.

Joint Forces in the Human Pelvis-Leg Skeleton DuringWalking : H . Rohdn .R. Soho!ten .C. Sigolotto, NiSo!!boch 'and H . Kellner (DorniarGmbH ' D-7QQOFriadriohohafnn1.West Germany) Journal of Biomechanics 17 :409-424, 1984.

Forces in the skeleton during walking are not extremelyhigh , but due to the frequently repeated load cycles thereare great demands on the durability of the skeleton andjoints . For the calculation of the joint forces, data of thethree-dimensional motion of the body need to be obtainedwithout restricting gait . Distribution of forces betweenfoot and ground is to be measured in a sufficiently largenumber of healthy persons in order to evaluate the jointforces of handicapped subjects . The external forces actingon the leg consist of the components of the foot-groundforces and inertia forces of the thigh, shank, and foot . Thecalculation model has three degrees of freedom describ-ing 1hehip.onefor1hehnne ' andtwoforthaenk!e.

The gait track is 8 .1 meters long with a Kistler forceplate and moving marks along the sides for speed align-ment . A camera tracking system records the motionsequence. The optoelectronic system consisting of 18Selspot 700 units records the movements of infrared-light-emitting diodes attached to the subjects . Prior to calcula-tion ofjoin1forcea ` anidea!izedbune'muaoieoonU guraUunfor a normal person based on anthropometry is needed toprovide joint axes, coordinates of joint centers, and muscleorigina, directions, and deflecting points . Linear transfer ofthe muscle idealization to each test person is applied to

the thigh, shank, and foot . Weights and centers of gravityof body parts are taken from idealized data and applied toindividual subjects . The analysis includes the influence ofinertia forces due to the translatory three-dimensionalmotion of the body parts . Coordinates of the light-emittingdiodes and the imaginary joint points are known in theupright position, permitting calculation of the position ofthe time-dependent joint position.

For determination of muscle and joint foroeo, the geo-metrical situation is taken into account, with bonesassumed to be rigid. Muscle and inertia forces are calcu-lated based on .nqui!ibrium of moments at the joints.Electromyographical measurements permit distinguishingbetween high and low levels of muscle activity . Gait meas-urements produce angle-time graphs of time-dependentpositions of the skeleton . Inertial and foot-ground forcesinfluence calculation of muscle and joint forces (fast walk-ing increases vertical force up to 30 percent) Since foot-ground foroedoeeno\peaa\hnoughthekn*eandhip ' )ointforces are much greater than foot-ground force . Joint forcesvary linearly with gait velocity, and the load during terminalstance exceeds the values of the prestance.

Leg Exerciser for Training of Paralyzed Muscle by Closed-Loop Control : J . S . Petrofsky, H . H . Heaton and C. A.Phillips (National Center for Rehabilitation Engineering,Wright State University, Dayton, Ohio) Medical endBie!ogioe!EnginoehnAsndCompu1ing22:2QB-303,Ju\y1984.

A leg trainer was invented for paraplegics and quadri-plegics which involves a stimulator controlled by a micro-computer . The stimulator control assembly is built on asingle plug-in card for the Apple II microcomputer . Pulsesof variable amplitude from the assembly board go to anaccessory module placed near the subject . The modulehas two transistors . The subject sits in a specially designedchair with surface electrodes placed over the muscle groupto be stimulated. The electrodes are made of carbon-filledelastomer. The chair contains a leather harness wornaround the ankle . The harness is attached to an isometrictension transducer bar through cables and pulleys . Twostrain gauges are mounted on the bar . When the muscle iselectrically stimulated, the tension can be recorded and isused to determine the maximum isometric strength of themuscle and the workload . Weights can be placed in theapparatus so the leg as it extends lefts the weights . APrecision potentiometer measures leg movement andtransmits the measurements to the computer which cansample knee position to see how effective the stimulationwas.

The software program has one section which involvesmeasuring the threshold voltage (just enough to make themuscle move), and the voltage that produces maximumcontraction . A series of pulse trains is applied to themuscle with increasing amplitude and the strength devel-oped by the muscle is measured . The muscle will developisometric tension until the maximum isometric tension (orpain) threshold is reached. Once this occurs, the operator

60

ABSTRACTS OF RECENT ARTICLES

presses an escape button to tell the computer the muscleis developing its maximum isometric strength . The com-puter ueeot maximum strength to set the workload; firstno load,

er 25 or 50 percent of maximum . Thecompute

,rir the appropriate weight to be added totie trainer t allow the exercise to be performed . After

!Jh1 is added, the operator cues the computer and thesnle contracts isokinetically . The stimulator causes the

r eo!e to lift the weight through a 60-degree arc over 3seconds, then slowly to lower the weiaht.

Submaximal exercise causes strength to return rapidly,but bone size and density are not restored quickly . It isimportant to examine for stress fractures in osteoporoticbone. Because patients with spinal cord injury lack sensa-tion in the affected limb, it is important that they be checkedtor burns over the electrode site . Stimulation is restrictedto nues m .oeeaib!e to surface electrodes . LocalizedhypE

unbalance forces that normally stabilize]oin1

sonthly radiographs should be taken toof_ Jr 3-spur formation, abnormal joint interspaces,

or stress ra ptures.

Mechanical Effectiveness Studies of Lumbar Spine Ortho-ses: Alf Nachemson, Albert Schultz, and Gunnar Ander-son (Department of Orthopedic Surgery I, SahigrenHospital, University of Goteborg, Sweden)ScandanavianJournal of Rehabilitation Medicine, Supplement A139'149, 1983.

Four healthy young adults performed six tasks whilestanding with no orthosis, then with a Camp canvas corset,a Raney flexion jacket, and Boston brace fitted to provide0, 15, and 30 degrees of lumbar extension . Horizontal loadswere applied to a chest harness and vertical loads imposedby having the subjects hold weights in the hand . The sub-jects resisted weight applications in flexion, extension,right !aterial bending, and right twist . Subjects also flexedtheir hips 30 degrees and held their arms extended forwardwith "40-N" weights in each hand . Goniometric evaluationwas performed to locate the mass center at L3, and linearmeasurements were taken of the trunk at the L3 level.Twelve bipolar pairs of surface electrodes were placedlateral T8, L1, L3, and L5 vertebrae and over the rectusabdominus and oblique abdominal muodeai )ntradieoaipressure was measured by a pressure transducer in aneedle tip inserted posterolaterally into the center of thethird lumbar disc . intra-abdominal pressure was measuredwith a radio transducer swallowed by the subjects.

!nhadiecal pressure values with an orthosis were lowerin two-thirds of the exercises and higher in the remainingtaoha, compared with neorthuaieva!uae. !ntra,aUdominelpressures were generally low, although no clear trend indi-cated the effect of the orthosis, nor were there consistenttrends as to the effect of orthoses on muscular activity.Linear regression analysis of predicted spinal compressionversus measured intradiscal pressure suggested that allorthoses relieved spinal compression approximatelyequally . Spinal compression relief averaged 7 percent over

the 18 tasks, and did not show consistent relationship totask or particular orthosis.

Load distribution is probably determined primarily bysegment morphology and soft tissue properties, which arenot altered by an nrthoaia, rather than by inten**gmentalmotions; restriction is important when an orthosis is wornfor postoperative stabilization, but seems unrelated tolow-back pain . Gross motion restrictions are probablymore important to orthosis effectiveness in low-back painthan are intereogmental restrictions . An orthosis some-times unloads lumbar trunk structures significantly andreduces lumbar spine compression and lumbar erectorspinae activity by a third, although orthoses can increasemuscular activity . Orthoses did not raise intra-abdominaipressure significantly over the sustained isometric effortsstudied . No orthosis seemed clearly superior in mechanicaleffectiveness.

Assessment of Tissue Viability in Relation to the Selectionof Amputation Level : V . A. Spence, P . T . McCollum, Wi F.Walker, and G . Murdoch (Ninewells Hospital, Dundee,Scotland) Prosthetics and Orthotics International 8 :67-75,August 1984.

Noninvasive ancillary methods to aid in amputation!evel selection allow estimation of the critical level ofischemia . Presently favored is measurement of segmentallimb blood pressures byDoppler ultrasound nrp!e(hyame

gnsph y ' although the measurements are unsuitabie forestimating the precise level of amputation . Low pressuresat the ankle should not exclude below-knee amputation,because local intrinsic regulatory mechanisms can allowadjustments of volume flow in microcirculatory vascularbeds . Only methods which measure capillary flow to theskin in potential amputation flaps are uneful in site selec-tion.

Am!croe1ectrodeconsisting of a 15-micrometer platinumwire encased in glass of approximately 70 micrometersmeasures skin oxygen par1ial pressure . Little differenceexists between measurements at normal skin and in thepnoximal leg skin of patients requiring below-knee amputa-tion, probably because skin has a baseline blood flowmuch greater than its nutritional demands . Reduced pres-sure exists in the dorsal foot skin in amputation patients.The procedure is difficult with patients who have ischemicrest pain.

Pressure measurements must be related to meaningfulphysiological parameters associated with tissue oxygenexchange . Transcutaneous oxygen measurements alsoreveal good amputation sites.

Measurement of skin blood flow by the rate of removalof a freely diffusible radioisotope such as 133-Xenon in-jected intradermally is simple, inexpensive, and reproduc-ible . lodoantipyrine is preferable for use in fatty tissues . Asimple method for preparing a stable solution which doesnot undergo radiolysis has been developed . The clearancemethod only provides an estimate of blood flow at a singlepoint . Measurements made in the foot are of little use in

Journal of Rehabilitation Research and Development Vol . 22 No . 11905

determining healing potential.Thermography provides detailed direct information re-

lating to the circulation through whole areas of eh!n, al-though the method lacks necessary quantification . Adirect relationship exists between temperature gradientsand skin blood flow measurements in the ischemic limb.

The Nonsurgical Management of Odontoid Fractures inAdults : Gwo-Jaw Wang, Kevin Mabie, Richard Whitehill,and Warren Stamp (Department of Orthopaedics andRehabilitation, University of Virginia N4edicu! Center,Charlottesville, Virg inia) Spine 9 :229-230, April 1984.

Odontoid fractures account for 10-15 percent of allcervical spine fractures, with earlier u5O-8O percent mor-tality and nowab-8 percent mortality . CurnanUy, high non-union rates complicate management . Twenty-five adultfractures were treated by closed methods during a 5-yearperiod . Four patients had spinal cord dysfunction . Sixteenpatients were treated initially with traction, then in halo-thoracic orthoses to limit atlanto-axial motion . The othershad a collar or other brace.

The patient with avulsion fractures at the alar ligamentinsertion had a halo-vest with ultimate union . Those withfractures extending into axial body had a Philadelphiauo!!ar, halo oeot, or halo-vest, and all achieved union . Pa-tients with fracture at the junction of the process and bodyhad either halothoracic immobilization or a collar or brace.Forty-two percent had nonunion, with halothoracic immo-bilization resulting in a lower rate of nonunion. Althoughdisplacement did not affect the outcome of fractures atother sites in the odontoid, most of the nonunions occurredin displaced fractures, especially if a collar or brace wereused. Only a fifth of nondisplaced fractures treated byhalothoracic immobilization resulted in nonunion, and nosignificant difference exists in the results obtained fordis-placed fractures treated with halothoracic immobilizationversus collars or braces.

Electromyographic Results of Inhibitory Splinting : VirginiaMills (Braintree Hospital, Braintree, Massachusetts)Physice 1 Therapy 64 :190-193, February 1984.

Eight t^x',"xnmi\hopaoioih/caused byhead trauma cvsubarach

irhage secondary to aneurysm receivedOr h

rp!into bivalved and lined with Po!y'oua . .

1tect . The splint positioned thejoint =

`/ i!a full passive range . Anklepdamx

' e lbow flexion were studiedby r .

nonsplinted restingposi

rol contraction wasisometrically

contrf

resistancefon5 f

eliminatedpositi

measured

goniometric position of the limbs into extension in thesplinted oondition, but no significant reduction in electro-myographic activity was found in the splinted condition,although 7 of the 10 limbs showed decreased activitywhen splints were worn . Muscle groups accommodated tothe elongated position achieved by splinting, evidenced byno change in electrical activity . Splinting is effective incontrolling postural defects and deformities without chang-ing muscle activity . Three patients exhibited increasedelectromyographic activity with splinting, indicating theneed to study cases individually.

Sitting Orthosis for Patient with Bilateral Hip Disarticulatbon : Roman Oryehkevinh ' VVon HeumJh*e . Ronald Wil-cox, Coleman, and Ed Ayyappa(Veterans Admin-istration West Side Medical Center, Chicago, Illinois)Archives of Physical Medicine and Rehabilitation 65:270'278 .K4ay1984.

A5Q-yeapo!d man with right hemiplegia and bilateral hipdisarticulation received a sitting prosthesis which enabledhim to sit securely in the wheelchair and propel the chairindependently . The socket was made of Thermovac 0 .6-cmthick and fully lined with 1 .3-cm perforated Plastazote . Thebase of the orthosis was rigid polyurethane foam coveredwith polyester resin . Beneath the base, plywood provided alight, strong foundation . The base was padded with Kemblorubber . The orthoeiowaa designed like a bucket, with thepatient's weight distributed over a broad area. A frontopening proved practical . The patient was placed into thesocket and the apron strapped to prevent his falling out.Theentire orthoeiavvaestrapped toiboback ofthewheel-chair . A window on the apron and corresponding depressionat the base accommodated a urinal . Two persons are re-quired to assist the patient into the orthosis . Theorthneiealso enabled the patient to sit on the floor or in bed.

The Technique of Reciprocal Walking Using the HipGuid-ance Orthmsiu(HGO) with Crutches : P . B . Butler, R. E.Major, and J . H. Patrick (The Robert Jones and AgnesHunt Orthopaedic Hospital, 0swestry, Shropshire, UnitedKingdom) Prosthetics and Orthotics International 8 :33-38,April 1984.

Walking in complete paraplegia above Ll requires eitherthe swing-through or reciprocal gait ; the latter reduces thevor!oal excursion of the center of mass to provide moreefficient walking and can be obtained in long-leg caliperswith high energy cost and slow progression . Body brace/calipers restrict flexion/extension . The HGO providesstability and hip control . The orthosis, for children andadults, consists of a rigid body brace to abduct the legs, apair of hip joints with limited flexion/extension range,stable knees and ankles, shoe plates with rocker soles anda simple fastening arrangement . The body brace is alumi-num aUuytubu!orandohanne!eeotionvvitha!eetherrhem\

62

ABSTRACTS OF RECENT ARTICLES

strap . On the buttocks a polypropylene support band isattached directly to the bearing housing . At right crutchstrike, lateral movement to the right commences as mostweight is transmitted through the right foot . The left crutchis slightly ahead of the left toe pushing down and back totilt the user to the right to clear the left leg . Forward trunkmomentum assisted by the rearward left crutch forcemoves the right hip over the right stance foot . The HGOprovides a reaction force on the right chest wall . Mechanics,muscle action, and orthotic reaction for the remainder ofthe cycle are described.

Four groups of users are those who are unable to performoompotenUy, those who use a rollator or crutches forthree-point contact, those who use crutches for two-pointcontact, and those who show random crutch use.

A Method for Determining the Mechanical CharacteristicsmYCy rthotic Knee Joints : R . P . Scothern and G . R . JohnsonDepartment of /Weohunioa! Engineering, University ofNewcastle-upon-Tyne, United Kingdom) Prosthetics andOrthotics International 8 :16-20, April 1984

A method of destructive testing by bending about themediolateral and anteroposterior axes allows measurementof the bending strength of a knee joint side member assem-bly, and definition of the brittleness of the failure . Theangular deflection was compared with the bending momentfor a variety of sizes and types of joints, all loaded undera uniform bending moment. Rollers were mounted in pairson the faces of two pulleys . Equal and opposite torqueswere then applied to the pulleys . Angular deflection wasmeasured with a Linear Variable Differential Transformercoupled to a pulley . The joint was placed in the test rigwith the lock in the center. Load was slowly increased untilany part of the assembly fractured, the lock opened, thespecimen deflected markedly, or the specimen continuedto deflect while the bending moment remained constant.Each joint was tested in f!nxion, extension, and medio!ut-era! bending in two directions . The elastic region ends atthe limit of proportionality, after which the graphed resultsshow plastic permanent deformation . The bending strengthwas defined as the limit point of proportionality . Ductility/brittleness was measured by the plastictelastic ratio; thehigher the value, the more ductile the failure, and thesmaller the chance of injury to the Wearer . A ring lockfailed when loaded in flexion because of insufficient con-tact aneabetwewnthotonpueand\heringoUmwinOp!aeticdeformity of both components . A bar lock loaded in flexionfailed because of double shear of the hinge pin . A bale lockfailed because the locking spring was weak or a largewedge of materiul was sheared off . Satisfactory failuresare associated with ductility in which the first componentto fail is not a casting and double-shear failure of loadedpins is avoided .

Potential Problems of Manufacture and Fitting of Poly-propylene Ultralightweight Below-Knee Prostheses: P.Covory .D. Jones, J . Hughes, and G . Whitefield (NationalCentre for Training and Education in Prosthetics andOrthotics, Glasgow, Scotland) Prosthetics and OrthoticsInternational 8 :21 -28, April 1984.

The ultra lightweight prosthesis was developed in 1976at the Moss Rehabilitation Hospital with a hollow foot andSACH hoel wedge. The 1978 version from Rancho LosAmigos Hompitol had a ho!!ovv'externa!-kee! SACH foot.The primary expectation was that saving weight wouldminimize energy requirements, but this has not beendemonstrated. Aoi\nioa! evaluation was conducted with asupracondylar socket with a Pe-Lite liner, mated to a hollowcalf and a keel bonded to the flexible soleplate of an OttoBook !S19 foot . A cosmetic cover was fitted . A manual ofthe manufacturing method is available from the authors.

Prostheses are now manufactured with 4.5-mm-thicksockets to eliminate excessive mediolateral flexibility . Be-cause the keel of a standard SACH foot proved to be tooshort (upon removal of 4 mm to allow drape of the poly-propylene) an oxtarnaikoel foot is now used . To avoidshrinkage of the medioia1e/al socket brim, vacuum wasreduced to 400 mmHg, the cold water quench was excludedfrom the manufacturing process, and the calf section waswelded to the socket at the patellar bar level rather thanaround the brim . Additional polyurethane foam is used tocompensate for shrinkage when foam is draped withpolypropylene . Because temperature and rate of heatingare critical, a small sample of polypropylene should beplaced in the coolest spot in the oven : when the samplebecomes tranoparont, the plastic is ready to drape . Ex-truded sheeting of ICI block copolymers to grade GPE 102with tan additive is used . Securing a permanent bondbetween the soleplate and the keel remains unsolved . Thevertical transfer jig makes foaming the calf section easierand minimizes loss of alignment . Improved techniquepermits accurate mating of the calf and socket, and alsoof the keel and soleplate.

The Distal Blood Pressure Predicts Healing of Amputationon the Feet: PerHolstein (Department ofClinical Phyai'o\ogy.Biepab>ergHoepita!,Coponhagen,Uenmark) AotaOrthopaedicaScandinavica 55 :227-233, April 1984.

During u7-year period, 142 foot amputations were per-formed in 134 patients . Two-thirds were men, and 80 percenthad diabetes . Primary closure was made in only 15 forefootand 3 digital amputations . Patients with systolic digitalblood pressure less than 20 mmHg had a 17 percent heal-ing ro1e, while 78 percent of those with pressure above30 mmHg healed . The healing rates in nondiabetic casesequalled those of diabetics . The diabetic legs that failedto heal had a high pressure and invasive infection . Secondtoe pressure measurements are useful where the first toeis not available . With systolic ankle blood pressure below50 mmHg, no feet hea!md, and with pressure above 100

63

Journal of Rehabilitation Research and Development Vol . 22Nu1 1885

mmHg, 72 percent healed . Healing rates in diabeticsequalled that of nondiabetics . Equal healing occurred inforefoot and digital amputations . Ankle pressure may befalsely high because of rigid arterial walls . With perfusionpressure on the forefoot below 20 mmHg, half the patientshealed . Ankle pressure is still a valuable predictor becausevalues under 50 mmHg indicate that the limb is seriouslythreatened . The digital pressure is the best predictor ofhealing, skin perfusion pressure is valuable in determiningthe !*vnl of major amputation . Pressures below 20 mmHgare very predictive of healing failure in the foot . Healing onthe foot requires a higher preoperative perfusion pressurethan does major amputation which leads to better circula-tion of the remaining stump.

The Outrigger Problem in Hand Splinting : Erik Moberg(Department of Hand Surgery, Sah!g/enmka Hospital,Gotegorg, Sweden) Scandinavian Journal of Rehabilita-tion Medicine, Supplement 9 :136-138, 1983.

Large outriggers on hand splints sometimes cause thepatient to refuse to wear the device. Outriggers tend tohook everywhere, disturbing sleep and dressing . They arealso very conspicuous . Outriggers are important to obtainthe right angle of pu!l by the elastics, and are used toreduce the differences in pull between various positions offlexion and extension.

Sufficient length of elastics may also be achieved byuse of almost frictionless pulleys which elongate thepathway of the elastics without changing their direction ofpull . Pulleys must be built on the rolling principle 1ocom-pensate for the high friction coefficient in elastics . Dispos-able hypodermic syringes are a very good material for thepulleys . They are shaped with a hack-saw blade and bondedtogether with fast acting cyano-acetate glue.

Orthwotie Management of Scoliosis in Duchenne MuscularDystrophy : Barry Seeger, Andrew Sutherland, and MichaelClark ( nny

k Centre for Young Disabled, Kilkenny,Austrs'

` mh

of Physical Medicine and Rehabilita-tion65:L

y1984.

The sdo little toOrthotionmodificationis avoided be n

comfort . Wmtotal-contacttion. Thefaintensive.is used.

mine the reand orthoture was

Seats were used for approximately 12 hours a day, andjackets for 7 hours daily . Each child progressed throughseveral types of support . in general, modular seats wereused by those with less deformity ; children with greaterdeformity had custom-molded seats and spinal jackets.Children exhibited a significant increase in curvature afterage 12, and no increase beyond 18 years . Among boys 14to 16 years of age, the best results were obtained using aapinal jacket, followed by modular seating, unmodifiedwheelchairs, andcustom-molded seating (the only statis-tically e1gnificant difference was that between the jacketsand the custom seats) . Spinal support systems failed tokeep the youngster's spine straighter for longer . If curva-ture can be controlled surgically, then the emphasis inwheelchair design can be comfort, appearance, and maxi-mum function.

Assessing the Reliability of Measurements from the KrusenLimb Load Monitor to Analyze Temporal and LoadingCharacteristics of Normal Gait : Patricia Carey, StevenWelk, Stuart Binder-Macleod, and Raymand Bain (EmoryUniversity School of Medicine, Atlanta, Georgia) PhysicalTherapy 64 :199-203, February 1984.

The Krusen Limb Load Monitor consists of a pressuretransducer worn inside aeho* and a control box worn atthe waist . Output from the monitor provides auditory feed-back as weight exceeding a predetermined threshold issensed. !n1erraterund intrarater reliability of four physicaltherapists' computations of 11 variables from monitordata on 10 healthy subjects was assessed . The monitorwas attached to a strip chart recorder . Subjects walked attheir netural cadences over a 30-foot walkway . Ratersattended a series of practice sessions to gain familiaritywith monitor recordings . Subjects displayed significantvariability for step measurements of stance time, timefrom heel strike to peak force at heel strike, time from hemlstrike teak force at push off, peak from baseline toheel ~ t - '--d from baseline to push off. Significantrater r-

ility occurred for stance time and time fromhee!s i

i oak force at heel strike. Other step measure-ments significant subject-by-rater variability . Sincethe largest percentage of total variability was attributed tosubject variance, the step measurements were reliable.Subjects also had significant variability in gait measure-ments of ambulation time, velocity, cadence swing phasedurations, and ratio of uni!a1erel weightbearing . Ratervariability was significant for average swing phase duration.

intenateranU intrarater reliability was very dependablefor individual step time and force variables and overall gaitvariables of ambulation time, vn!nci1y, and cadence . im-provement in instructions for determining average swingtime and ratio may insure greater accuracy.

ck of the conventional wheelchairrmity in muscular dystrophy.i'heron aapina! orthosis or

seat and back . The corsetdmonaryproblems anddi*"me,imea custom-molded

by vacuum consolida-consumingemd!abor-

eeatinginoerts

years to deter-eichair seatsSpinal oumaradiographs .

64

ABSTRACTS OF RECENT ARTICLES .

The Clinical Engineering/Health Care Mismatch : Its Effecton Personnel Management: L . Fennigkoh (Saint Luke'sHospital, Milwaukee, Wisconsin) Medical and BiologicalEngineering and Computing 22 :113-114, March 1984.

Personnel management is especially stress-inducingwithin hospital-based clinical engineering departments,where thing-oriented people (such as engineers) amex-pected tofunoUoninmpeopio-ohontedayatem . Job differ-entiation is necessary if specialists, such as clinical engi-neers, are to perform effectively, while job integration isrequired for the hospital to function as an organizationwith coordination among specialists . An antagonistic,inverse, relationship exists between job differentiation andintogo8ion, so that the more two specialists differ in pat-terns of behavior, the more difficult it is to integrate them.Clinical engineering's lack of acceptance as a professionis due, in part, to the high degree of differentiation thatexists between it and the rest of health cane-- becauseclinical engineers are uniquely attracted to things ratherthan to people. Achieving integration, while a managementparadox, is possible only through good communicationchannels . Engineers must improve communication skillsby becoming involved in local engineering organizations,1eaohing, presenting teohnioal papers, conou!ting, sub-scribing to people-oriented publications and being willingto take mental risks. Engineers relate upward to thehospital administrator, downward to technicians, andlaterally to other department heads . The ability to getalong with people, rather than technical skills, is perceivedby hospital administrators as the clinical engineer's mostimportant quality.

Prosthetic Alignment : Effect on Gait of Persons withBelow-Knee Amputations: R . E . Hannah, J . B . kAoniaon,and A. E. Chapman (University of British Columbia,Shaughnessy Hospital, Vancouver, British Columbia,Canada) Archives of Physical Medicine and Rehabilita-tion

Five men with below-knee amputations walked on ad-justable prostheses . They wore plastic laminate patellartendon-bearing-type sockets with solid-ankle cushion-heelfeet . Alignment devices were Winnipeg wedge disc align-ment units or four-screw temporary alignment jigs . Electro-goniometers were attached bilaterally at the hips andknees. A knee measuring module was attached to theprosthesis pylon to record rotations about three mutuallyorthogonal axes. Subjects were fitted at least 3 weeksprior to the measurement session. Optimum alignmentwas established using standard clinical techniques . Gaitrecording was made as the amputee walked along a 10-meter walkway on a free time walk.

The objective of data analysis was to determine whethermaximum symmetry of lower limb kinematic variablescoincided with optimum prosthetic alignment . Indices ofsymmetry were developed for time and frequency . Changesin pylon lengths resulted in the least number of aaym'

methou undoagd(al foot realignment resulted in the larg-est number. Knee va\gua-varue motion and hip flexion-extension motion times were most frequently affected byalignment changes . Least affected were hip and kneetransverse plane motions. Although the relationship ofkinematic variable symmetry to ophmal prosthetic align-ment has been delineated, the current method requireslarge alignment changes to elicit changes in symmetrywhich achieve o1a\iaUoal significance . It is therefore im-portant to differentiate between detection rate and signifi-cance when assessing the effectiveness of the asymmetryindices.

Lateral Electrical Surface Stimulation as an Alternative toBracing in the Treatment of Idiopathic Scoliosis : LynnEckerson and Jens Axelgaard (Rancho Los AmigosRehabilitation Engineering Center, Downey, California)Physical Therapy 64 :483-490, April 1984.

Idiopathic scoliosis comprises approximately 75 percentof all scoliosis in the United States . One of the mostcommon treatments for progressive curves between 20and 45 degrees has been the Milwaukee brace worn 23hours daily until the patient nears akm!etal maturity . Al-though the brace can halt progression, problems compli-cate its use. Wearers cannot participate in sports andexperience clothing wear, pressure sores, difficulty workingat adook because of the chin piece, and negative psycho-logical changes . Braces entail significant initial cost andmust be replaced as the child grows . Low-profile braces,such as the Boston brace, eliminate some but not allproblems.

Electrical stimulation for mild to moderate curves wasfirst attempted in 1974 with intermuscular electrodes inthe pmreep!nal muscles . Following animal studies, patientselection criteria were developed that required that thecurve be id!opa\hiu, pnngrmeeivo, between 20 and 45 de-grees, and in apag ien\ having at least 1 year of growth re-maining . The pvo1ocnl for subjects includes inihal assess-ment, then stimulation with the Scolitron for single curves,andfordouble curves, ua*ofaspecial dual-channel stimu-lator . Stimulators deliver trains of 25 rectangular constant-current pulses per second, 6 seconds on and 6 secondsoff, transmitted through carbon-rubber electrodes . Pa-tients kept a diary regarding the time and amplitudeof stimulation, and a compliance meter located in theScolitron was also used. Electrodes were placed on themidaxillary line lateral to the apical rib or vertebra onthe convex side of the curvature . Palpation of spinal move-ment of all curves is necessary before selecting final elec-trode and polarity . Amplitude and treatment timeare increased gradually to allow for sensory accommoda-tion and1oavoid muscle soreness . Stimulation continuedun\il eke!cSal maturity was maohed, without a weaningperiod . Of 57 patients who used the treatment for 6 to 42months, 12 had been braced prior to electrical stimulation.To1al compliance was reported in those who had wornbnaces, and 90 percent of those who had no prior brace

Journal of Rehabilitation Research and Development Vol. 22 No. 5 1985

were compliant. Few had difficulty sleeping with the stim- ulation. Proper electrode placement presented no problem to 93 percent.

Pathologic Gail Diagnosis with Computer-Averaged Elec- lromyographlc Profiles: David Winter (Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada) Archives of Physical Medicine and Rehabilita- tion 65:393-398, July 1984.

A suitably chosen analog electromyographic signal can represent the pattern of muscle activity more meaningfully than the common practice of noting only the on and off times of each muscle, because the phasic patterns do not include the threshold for turn-on and turn-off. The new technique records five muscles and one footswiich signal, using a biotelemetry system, electromyographic processor, and computer. The signals were processed to produce a linear envelope (full-wave rectifier followed by a second order low-pass filter with a cutoff at 3 Hz). Each subject was tracked with a television camera mounted on a cart that followed the individual on a 10-meter walkway. The linear envelope and footswitch signals were converted at 250 samples per second by computer. Time averaging of each recording over each stride was accomplished by nor- malizing each stride to 100 percent and then averaging each stride at each 2 percent interval over the stride. The mean electromyographic signal in microvolts (ensemble average) was plotted to form curves for each subject. Using time averaging, the intersubject averages for 11 able-bodied persons walking at their natural cadences were obtained. Work is ongoing to expand the muscular curves l o 15 from the lower limb.

Cerebral palsied children were assessed in the same manner and their curves compared wilh those of able-bodied subjects to provide a rapid and objective technique to assess each muscle's pattern of activity and identify periods in the gal"rycle when abnormalities occur. Future developments include defining changes related to cadence, for it is incorrect lo compare a slow-walking patient wilh able-bodied persons who walk considerably faster. Speed- related profiles are needed on each muscle. Efforts are also required to devrse techniques to account for intersub- jeci variability among normal profiles due to measurement and biologic dlffWw'Ice8

Wheelchair MaualaSnssrlng: dulls Madorsky and David Kiley (Casa Ccriina Hosptral tor Rehabilitative Medicine, Pomona, Galrfornra) Archrvs% of Physical Medicine and Rehabilitation 65 490 492, August 4984

A 28-year-old d~recror i r f t.kr~c~dpsuPtc recreation with in- complete L I paraplegia W ~ + P psrt vl a sex-man learn of wheelchair-bound indlvidtaaIr tnat cirmbscf to the summit of an 8751-fool mountairs #*a *5,ky* fjrirr*"aq racn and thunder- storms. The director rlsed k iraf*iv#dat~%5i: ,d;unrtnurn Quadra

wheelchair equipped with 24-inch wheels. Three-inch pneumatic tires with deep tread provided strong grip on the gravel trail. Eight-inch-wide inflatable front tires were used. A compartment under the seat stored gear. Padding inside the trousers seat protected the buttocks and lea"rer gloves reduced hand Glisters. No able-bodied person gave assistance during the climb, although park rangers pa- trolled the trail. The final day was spent climbing a 35 to 45 degree slope by crawling and clawing their way up, pulling the chair by a rope clenched in the mouth. After determining that the descent would be too treacherous, they were rescueklby helicopters from the summit. The leader developed a 4.5 x 4 cm superificiai sacral abrasion and a 2 x 2 cm skin breakdown over the Achilles tendon, both of which healed within a few days. Wheelchair moun- taineering is a form of exercise, endurance, and survival training which can be a valuable tool in the physical and emotional rehabilitation of selected individuals. Referral to self-help groups, such as Paraplegics on Independent Nature Trails, deserves serious consideration.

Energy Expenditure of Paraplegic Patients Standing and Walking wilh Two Knee-Ankle-foot Orthoses: Kurt Mer- kel, Neil Miller, Philip Westbrook, and John Merritt (Mayo Clinic and Mayo Foundation, Rochester, Minnesota) Archives of Physical Medicine and Rehabilitation 65: 121-124, March 1984.

Eight subjects with complete motor paraplegia partici- pated in the study, wearing Scott-Craig and single-stopped knee-ankle-foot orthoses. Lesion levels ranged from C7 to T12. Six subjects regularly used Scott-Craig orthoses and two wore single-stopped ones. Data was collected as sub- jects sat, stood, walked with a walker, and walked with crutches with trainer versions of each type of orthosis. Energy expenditure was essentially the same during standing and walking with either type. With Scott-Craig orthoses, velocity was 8.8 meters per minute compared with 6.3 with a single-stopped orlhoses, indicating the Scott-Craig devices to be more energy-efficient. Crutch ambulation with Scott-Craig devices cost patients 25 per- cent less energy, and they achieve 34 percent greater energy efficiency, although velocity was not appreciably greater. The anterior ankle stop in the Scott-Craig orthoses substitutes for the action of the gastrocnemius-soleus muscle to reduce the vertical amplitude of the center of gravity during ambulation. The ankle bar provides medio- lateral stability to reduce the amplitude of the center of gravity in the horizontal plane. As compared with able- bodied individuals, paraplegic subjects wearing Scott-Craig orthoses expend 5 times more energy with crutches and 8.8 times more with a walker. Those with single-stopped orthoses use 7.7 times more energy with crutches and 12.8 times more with a walker.