170 Abstracts I Gait & Posture 7 (1998) 144-190 Vmiabk Pqlumt I Year Post p&e Mmisrlml Pelvic Tut 18.9 (b) 13.70(interior) 0.0042 Maximum Hip FIeaiat 40.40 34.00 0.0020 Avmse Hip Adduction 5.40 3.30 0.0064 Table 2: Significant (pCO.OS) deviations in gait due to prekmettcy. Means for each condition and pvalues horn staietieal analyses are presented. Mrusioa Little evidenc=e was found to support the popular cmttenticm that prgnnnt women exhibit a “waddUi gait”. T&c mutts of this study show that nommlized base of support width. pelvic obliquity-of motion, and foot pmgrrssion angle are all tmekanged during pregnancy. The ehangsain gait duing la%gttency quantified by this study are mild and can be explained by changes in mass distribution about the tnmk, end increases in body mass and pelvic width. The significant inacav in anterior tilt of the pelvis during pregnancy that was obeuved wes p&ably a rcadt of the itmeae in the amount of body mull kated in a low anterior position onth+tmokdwingpregaancy. Aninaasedantetiorloedcntthelowertnmkeotdd~erate a forwzrd rot&g moment tending tn tutate the pelvis anteriorly. Increases in anterior Pelvic tilt generally recult in inuewed tumbv lord&s and may contribute to increased stress on the low back and secmiliac (St) joints during pregnancy. The in- in body mass during prqpwcy apparently necsspitetedthe increased stance side intemel hip aMwticm moment during etmtce. btemsiingly. small but significant increases in double~anddcasascsinsinslesupporttimesduringprrgMney~tobe compnspfim to minimize the time spent in singk limb e wkn this increased muswkr effort is required to support the increased body mass. Compensation for an increased pelvic width during pregnancy apparently occurred in order to avoid walking with a wide bawd, energy-inefficient gait @tern. Hip adduction was increased during the single suppon phaseof gait in order to keep the foot centered under the body and optimize baseof support. Ilerereaen Bullock I.E. etal.. AusfrJfhysiorher, 33:ll-17, 1987. MwreKetal..Proc C~~.~oe.forBiom..Fi~hBienniolConfandSymp., 114-115, 1988. Snijders I.G. et al Digest o/the II” /n&r. Conf on Med and Biol Eng, Ottawa. 1916. Posters COMPARISON OF AMBULATlON (WALKING AND HOPPING) IN NORMAL CHILDREN AND CHILDREN WlTH ABOVE-KNEE AMPUTATIONS Anita Be&v. PhD., Jon R Davids, M.D., Theresa Foti, Ph.D Sbriners Hospitals for Children, Greenville, SC 29605 INTRODUCTION: The ability of children with above-knee amputations(AKA) to walk efficiently is a function of residual limb length, underlying bony alignment, muscle strength, and pmstbetic fit end design. Hopping, which is a typical metbud of household ambulation for AKA individuals, may be the principal mode of gait for AKA children in under-served areas of the world. who have improperly fitting pmnheses or lack them altogether. The purpose of this study was to provide kinematic and kinetic pmtiles of these children both walking and hopping, and to compare their abilities to those of children with intact limbs. METHODOLOGY: Thirteen nomml (NL) children (8 female, 5 male; average age 9.4 yrs) end twelve AKA children (4 female,8 male; average age8.2 yi%) were analyzed with 3D gait analysis (Vicon 370,b camera,2 force plates) during walking and hopping at self- selectedspeeds over level ground. RESULTS: TimUDfstmcc: Both groups exhibited greeter speedin bopping then walking as e result of increwed cadence. NL demonstrated gwater velocity and cadencethan AKA in walking, while AKA demonstrated higher values in hopping. Kinematics At the pelvis, both groups exhibited increased anterior pelvic tilt and decreased pelvic rotation in hopping relative to walking. AKA demonstratedgreeter maximum anterior tilt and se&al plane range of motion than NL in both tasks. In hopping, upwards pelvic obliquity in stance increased for AKA and decreawd for NL (to below neural). Coronal plane renge of motion decreased relative to walking for both groups, hut to a greater extent in NL. At the hip, both groups exhibited less extension endmore internal rotation in hopping than walking. In both tasks AKA demonstrated greater hip flexion than NL and were, on aver&, positiomd in external hip mtation (versus M avenge internal position for NL) during stance. Maximum bitt dduction bweased for AKA end decreaed for NL durina hopping (the movements we& correlated with pelvic obliquity position). At the knee, both pups exhibited more flexion in stance, less flexion in wing, end more intend rotation durhtg k@tg than waking At the ankle, both graqw exhibited increesed dorsifkxion in hopping. For bath lasks, foot pmgressionaaglewesmextemalinAKAtbanNL. Kin&s: At the hip, both groups exhibited bweased bip extension mmnent and power generaion in hopping during swing and initial stance. Power absorption during both swing and stance were innraped (to a greater degas for AKA) as WBS abduction moment. At tk knee. bath groups exbibitcd 8 stansc pbau extension moment pattern and incased powergene&mduringluyping. Powerabsaplionvnwincrascddurbtgbdtialstawsnd decnucdntkendof-. At the adIe, both groups exhibited inaeasd plantar flexion moment, increased energy absorption in early stance (sccntric stretching), and increesed peek and totel energy generation for hopping. AKA energy levels for both absorption and generation changed from less than Niin \mlking to 8reeter in NL in hopping. A-” DISCUSSION: Both emum use similar me&anisms to hon. however. AKA use ho?‘-- - . .‘Y”W on a functional rather than recreational basis, aed have learnedto hop wll. This ability is reflected in their greater speedand cadence relative to NL, and in the resulting larger moment and power magnitudes. Experienced hoppers (e.g. track triple jump athletes) optimize energy transfer from the unloaded limb by swinging it in counterpoint to the active limb (i.e., the unloaded leg is rhythmically swung 10that the hip ip extendedet initial contact and flexed at toe-off). This motion WBS performed more fluently by the AKA than NL. Also, NL must compensetefor the additional weight of their intact leg versus the AKA residual limb. On the stance side in hopping, NL exhibited depressedpelvic obliquity (allowing the swing side to be lifted) and greater hip abduction relative to walking. Hopping increases loading on the joints of the lower limb and demanda8reater muscle strength then walking. Ankle plenterflexion moment end power demandsare signiticantly increased. The knee remains tlexed approximately 20 degrees in stance, resulting in an extension moment panem and high quadriceps demandfor shock absorption end stabilization (Fig. la). Hip abduction moment is doubled (Fig. I b), requiring compensatory (and energy expending) trunk positioning over the stance limb if glutew medius muscle strength is insufficient. In AKA walking, loads are applied asymmetrically and greater than normal loads have ken recorded on the unetTected side (Lewllen et al., 1986; Engsberget aI./ 1993). Hopping exacerbates this loading. In the short term. AKA hopping requires good bgny altgnment, balance end muscle strength. In the long term, increasedrepetitive lo& may be detrimental ifjoint health (e.g., cartilage integrity) and alignmentare not maintaineddue to associated congenital problems such es lateral femoral hypoplasia. Figure I (4 uY.-Y1 @) “IPYWEYI Figure la: Kneeextensiotiflexion moment in walking and hopping (NL andAKA). Figure lb: Hip abduction/adductionmoment in walking and hopping (NL and AKA). RB~EBEtiCES: Engsberg J. R. et al., JPedollhop, 13:169-173, 1993. Lewallen R. et al., J Fed Orrhop, 6:29l-298, 1986. ACKNOWLEDC.MENTS: The authors th& Steve Liou for his help with date reduction. Tibial fractera axewmmonly vcpted surgic& by intru&ullary nailing (IM Railing). One complicatbn of tbia procedure is tiblal mebndoa,which presents es a mtnt!onal deformity of thclibiavay1wcishawnboweva.~tbehridcnzoftibial~mtionrftcrIM naihg or the efkcur thir dehmity may kve on mrrcal liutctbm and bcomotbn. Ty@cdly. tibialex~mUIionofgmucrthn!200orintenvlmtationofgnucrt~1S0isco~~ seven enough to wurmt a demtadotmlosteo~my. Unfortunately there is no evidence in litem to suppotl thii practice. Tk purpose of this pnlimbmry study was to wantine deviations fmm normal gait patterns in patientswith severe tibial malmtins. Two patients (46 and 48 years) were testedjxior to undergoing a demtational osteotomy. A CT scatt was used to masun the severity of the tibial malmtatia~ based on tk technique presentedby l&b et al (1980). Refkctive markers were placal on the pelvis, thigh, leg, and foot to obtain tbne dimensiorul(3D) repreatetbm of tk aagmetttal movements. Video data were collected at 120 Ii& double tedmion U&III four Falcon Motion Analysis c-. EVa HiRcssoRwnrewrrusutfordur.mllstionuaallasto rsonanrttkmarkertflpccaricsin 3D. Rintrak mftware c&dated joint a+ utd morneete.Joint angles wem cakukted using tk joint coordinate systetn method, ad pia moments wcm cakulated in the rcspccrive segmentcoordhtete rystentr Gmutd reuaiat force data wae cdkacd (1uM Hz) using II Kistkr force plate. Data were colkzted et tlweeB wa!kbt8 speeds:natural walking speed.l.3mlsMdrshaulpoatibk.FivctriLharnecolMedstcrhspeedlndtk~uk were weaged togetkr. Read* Patientone WBS measured.clinically, at 20QeaQMl rotation while patient two was measured at 2S” extcmd rot&m. At the rdrk. patient one hada krgc planter tkxion in the beginning ofswcephPaeandpt~~~~~xat~off(Pigu~l).Bothplticnts exhibited a lack of tkrion at the bxe during stawe phase.ka+iig tka knee ettiff until toe Off. Patient one maintaixd a hrll extension angle.WhIk pntient two walked with a constant knee engk of about 15’ of flexan (Figure 2). Moment datafrom both patientswere atypical compared to nomkxl n&e vertkal gmlmd raction forcea Hem.lower than normal especially from mid-- to toe-off dcrbg the pmpebion pkak (Figure 3). and produced small moments at each of the lointe.. Patientoly demonetmted a rpSe flexor molacnt in tk middle of staxx plmae cap&d to normal gait d&e. Patienttwo. oitk otkr bend, mai&ned an mewion mom through tlm entire stance pluse ratkr thanchatglng from M extewion mmte.nt to a ma-e t?axor nmtent in tk middle of stance phase (Figure 4). All graphs are of tk affected limb although tk contrakeral limb also had abnomwal patrerns.