JKPT pissn Vol. 30, No. 1, February 2018 J Kor Phys Ther 2018:30(1): eissn X Original Article

pissn Vol. 30, No. 1, February 2018 J Kor Phys Ther 2018:30(1):14-22 1229-0475 eissn 2287-156X Original Article Pelvic, Hip, and Knee Kinematics of Stair Climbing in People with Genu Varum Yun Won Chae 1, Seol Park 2, Ji Won Park 3 1 Department of Physical Therapy, Gwangju Health University; 2 Division of Biokinesiology and Physical therapy, University of Southern California; 3 Department of Physical Therapy, College of Bio and Medical Sciences, Daegu Catholic University of Daegu, Korea Purpose: This study examined the effects of the lower limb alignment on the pelvis, hip, and knee kinematics in people with genu varum during stair walking. Methods: Forty subjects were enrolled in this study. People who had intercondylar distance 4cm were classified in the genu varum group, and people who had intercondylar distance < 4cm and intermalleolar distance < 4cm were placed in the control group. 3D motion analysis was used to collect the pelvis, hip, and knee kinematic data while subjects were walking stairs with three steps. Results: During stair ascent, the genu varum group had decreased pelvic lateral tilt and hip adduction at the early stance phase and decreased pelvic lateral tilt at the swing phase compared to the control group. At the same time, they had decreased minimal hip adduction ROM at the early stance and decreased maximum pelvic lateral tilt ROM and minimum hip rotation ROM at the swing phase. During stair descent, the genu varum group had decreased pelvic lateral tilt at the early stance and decreased pelvic lateral tilt and pelvic rotation at the swing phase. In addition, they had decreased pelvic frontal ROM during single limb support and increased knee sagittal ROM during the whole gait cycle. Conclusion: This study suggests that a genu varum deformity could affect the pelvis, hip and knee kinematics. In addition, the biomechanical risk factors that could result in the articular impairments by the excessive loads from lower limb malalignment were identified. Keywords: Genu varum, Stair climbing, Range of motion, Articular, Biomechanical phenomena 서론무릎의뼈관절염 (osteoarthritis, OA) 은노인에게서흔히볼수있는퇴행성질환으로, 가장대표적인변형은안쪽구획 (medial compartment) 의연골소실등으로인한안굽이무릎 (genu varum) 인데, 무릎관절전치환술 (total knee replacement, TKR) 을받은환자의 76.5% 에서안굽이무릎을가지고있었으며, 안굽이무릎에대한뼈관절염의교차비는 5.1인것으로나타났다. 1-3 뼈관절염의정도는경미하나심각한안굽이무릎변형을가지는환자들에게는무릎관절전치환술보다는정강뼈몸쪽뼈자름술 (high tibial osteotomy) 과같은재정렬수술을진행하는데, 이수술을통해무릎관절의이완과불안정성등에향상된결과를보였으나, 보행시운동형상학은여전히손상되어있는것으로나타나다리정렬과운동형상학의관계및이를해결하기위한재활에관한연구가필요하다. 4 안굽이무릎을포함한다리의부정정렬또한뼈관절염에영향을미친다. 안굽이무릎의경우부하지지축이무릎관절의안쪽을지나는데, 이축이무릎모음모멘트 (knee adduction moment, KAM) 에영향을미치며, 이모멘트는안쪽구획의관절부하를증가시켜안쪽정강넙다리뼈관절염 (medial tibiofemoral osteoarthritis) 과안쪽무릎넙다리뼈관절염 (medial patellofemoral osteoarthritis) 을유발시킨다. 1,5,6 또한보행시안굽이무릎에서는가로면에서넙다리뼈가쪽돌림과정강뼈안쪽돌림이나타나는데, 이는인대력의증가로인해안쪽구획에부하를증가시켜안쪽구획뼈관절염에관여하게된다. 7 특히, 안굽이무릎에서안쪽구획의연골두께가감소되어있다고보고한 Cicuttini 등 8 의연구와, 뼈관절염에서나타나는뼈곁돌기 (osteophyte), 섬유성연축 (fibrillation) 등뼈와연골의변화를안굽이무릎에서도발견한동물실험 9 을통해서도안굽이무릎이안쪽구획뼈관절염을유발시킨다는것을알수있다. Received Jan 9, 2018 Revised Feb 13, 2018 Accepted Feb 28, 2018 Corresponding author Seol Park E-mail parksul85@hanmail.net Copylight 2018 The Korea Society of Physical Therapy This is an Open Access article distribute under the terms of the Creative Commons Attribution Non-commercial License (Http:// creativecommons.org/license/by-nc/4.0.) which permits unrestricted non-commercial use, distribution,and reproduction in any medium, provided the original work is properly cited. 14 www.kptjournal.org

Stair Kinematics in People with Genu Varum 안굽이무릎의원인은다양하나, 최근들어청소년기에축구와같은격렬한운동을통해안굽이무릎이유발된다는연구가보고되고있고, 특히이러한운동은청소년기의안쪽구획뼈관절염또한유발시킨다. 10-12 이는비단비타민 D 부족, 외상및블런트병과같은특정된원인뿐만아니라, 신체활동이나생활습관이안굽이무릎을유발시킬수있다는것을의미한다. 특히뼈관절염의경우최근수년간젊은연령층에서급속도로발병률이증가하고있기때문에, 무릎뼈관절염, 또는뼈관절염으로인한안굽이무릎변형은더이상노인성질환으로여겨지지않으며, 따라서청소년기를포함하는젊은성인의다리정렬, 또는이로인한뼈관절염에관한생체역학적연구가필요하다. 13 또한, 젊은성인의뼈관절염발병과진행을예방하기위한방법으로무릎관절손상예방, 손상후재활, 규칙적운동, 적절한체중유지등이외에도보행패턴을변화시켜야한다는주장은보행패턴에관한기초연구의중요성을의미한다. 5 안굽이무릎은엉덩관절과발목관절을연결하는부하지지축이무릎의안쪽을지나는부정정렬이다. 따라서무릎관절의안-가쪽이완, 불안정성을유발하며, 이는결국정적, 동적불안정성도유발한다. 1,14 따라서부정정렬로인한기능손상은한관절에만국한되어나타나지않고, 인접한관절과의상호보완을통해다리전반에걸친보상작용으로나타나게된다. 특히, 안굽이무릎을가진안쪽구획뼈관절염은방사선상골반기하학 (pelvic geometry) 에도변화를보였으며, 15 이러한기하학의변화는운동형상학에영향을미치게되므로, 안굽이무릎을대상으로한운동형상학의연구는무릎관절에한정되지않고엉덩관절과골반으로확대되어야한다. 또한엉덩관절과발목관절의중심을지나는역학적축의변위 (mechanical axis deviation, MAD) 가무릎관절에서멀어질수록알파-각 (alpha angle) 이증가하였으며, 안굽이정강뼈 (tibia vara) 가엉덩관절의 cam 변형을동반하는것으로나타났으므로, 이들연구모두무릎정렬이엉덩관절과골반에영향을미친다는것을의미한다. 16,17 Cam 변형을가진넙다리절구부딪힘증후군 (femoroacetabular impingement syndrome, FAI) 을가진환자에게서감소된골반운동형상학을보고한연구결과들을미루어볼때, 안굽이무릎에대한골반과엉덩관절의운동형상학에대한연구도이루어져야한다. 18 안굽이무릎을재정렬하기위해시행하는정강뼈몸쪽뼈자름술수술이엉덩관절의생체역학에영향을미쳤다는연구또한안굽이무릎에대한골반및엉덩관절운동형상학연구의필요성을뒷받침해준다. 19 계단보행은평지보행에비해관절부하가높고, 더큰관절가동범위 (range of motion, ROM) 가요구되는동작이므로이러한도전적인동작을얼마나효율적으로하는지가삶의질 (quality of life, QOL) 을결정짓는다고볼수있다. 계단보행의효율성비교를위해우선되어야할기초연구가정상인과의운동형상학비교이다. 하지만계단보 행동안다리의운동형상학을보고한연구들은특정질환과관련된관절에만국한되어있는경향을보이며, 골반의움직임에관해보고한연구는부족하다. 특히, 가로면을포함한세면에서의운동형상학을모두보고한연구는극히제한적일뿐만아니라, 계단보행시안굽이무릎의운동형상학에관한연구는알려진바가없다. 따라서본연구는안굽이무릎을가진젊은성인을대상으로계단오르기및내리기보행시다리정렬이골반, 엉덩관절및무릎의운동형상학에어떠한영향을미치는지알아보고자하였다. 연구방법 1. 연구대상본실험은정형외과적, 신경외과적병력이없고무릎관절에통증이없는만 20세이상의젊은성인남녀 40명을대상으로하였다. 실험전안굽이무릎군과대조군으로분류하기위해피험자들을대상으로바로선자세에서무릎사이의거리 (intercondylar distance) 와발목사이의거리 (intermalleolar distance) 를측정하였다. 무릎사이의거리는바로선자세에서두무릎의안쪽관절융기 (medial condyle) 사이의거리를의미하며, 이거리가 4 cm 이상인경우안굽이무릎 (n = 20) 에배정하였다. 발목사이의거리는두발목의안쪽복사 (medial malleolus) 사이의거리를의미하며, 이거리가 4 cm 이상인경우는밖굽이무릎에해당된다. 본연구에서는무릎정렬상태가정상범주에속하는자를대조군으로선정하였으므로, 안굽이무릎과밖굽이무릎의범주에속하지않는, 무릎사이의거리가 4 cm 미만이고, 발목사이의거리가 4 cm 미만인자를대조군 (n = 20) 으로배정하였다. 20 피험자의일반적인특성을알아보기위하여나이, 키, 몸무게, BMI (body mass index) 를측정하였다 (Table 1). 피험자들은연구목적과방법에대하여충분히설명을들은후자발적인동의하에본실험에참가하였다. 2. 실험방법 1) 실험계단실험에사용된계단은가로 120 cm, 세로 28 cm, 높이 18 cm, 기울기가 Table 1. Anthropometric characteristics Variable Varus Control p-value n (M:F) 20 (5:15) 20 (7:13) 0.73 Age (yr) 21.25 (1.45) 21.40 (1.73) 0.77 Height (cm) 164.95 (7.45) 165.35 (8.95) 0.88 Weight (kg) 55.40 (8.05) 57.95 (13.1) 0.46 BMI (kg/m 2 ) 20.29 (1.76) 20.95 (2.59) 0.35 Distance (cm) 5.06 (0.75) 0.82 (1.37) 0.00 * BMI: body mass index, Distance: the intercondylar distance. * p< 0.05. www.kptjournal.org 15

The Journal of Korean Physical Therapy Yun-Won Chae, et al. 30 인 3단계단으로, 목재로제작되었다. 건축물의피난 방화구조등의기준에관한규칙제 15조에제시된계단의규격은가로 60 cm 또는 120 cm 이상, 세로 26 cm 이상, 높이 18 cm 이하로, 본시행령을준수하는문화및집회시설, 판매영업시설등공공장소에서쉽게접할수있는계단의규격을반영하여제작되었다. 2) 계단보행주기계단보행의주기는일반보행의주기와는달리, 계단오르기와내리기각각 5개의세부주기를가진다. 계단오르기는디딤기 (stance phase) 동안 (1) weight acceptance, (2) pull up, (3) forward continuance, 흔듦기 (swing phase) 동안 (4) foot clearance, (5) food placement, 계단내리기는디딤기동안 (1) weight acceptance, (2) forward continuance, (3) controlled Table 2. Stair ascent pelvic, hip and knee maximum, minimum and total kinematics in sagittal, frontal and transverse plane in people with genu varum compared to control. Stair Ascent Varus (n=20) Control (n=20) DS1 SS DS2 SW Total DS1 SS DS2 SW Total Pelvic kinematics ( ) Frontal plane Transverse plane Hip kinematics ( ) Frontal plane Transverse plane Knee kinematics ( ) Max 3.05 (7.46) Min -1.68 (7.26) Total 4.73 (2.56) Max 13.66 (5.79) Min 8.34 (5.05) Total 5.32 (2.19) Max -2.23 (3.9) Min -5.68 (4.64) Total 3.45 (2.59) Max 59.64 (8.53) Min 49.25 (10.26) Total 10.39 (10.62) 1.28 (6.86) 0.61 (7.47) -5.12-6.34 (7.78) (8.34) 6.4 (2.93) 6.95 (2.85) 11.55 (6.9) -11.45 (7.09) 23.00 (9.59) 4.27 (3.08) -3.30 (3.25) 7.57 (4.07) 48.72 (11.01) 3.44 (6.87) 45.28 (13.05) Max 9.31 (5.62) 9.32 (6.68) Min 2.78-10.47 (5.67) * (7.31) Total 6.53 19.79 (3.36) (8.12) Max -7.21 (3.48) Min -11.86 (4.15) Total 4.65 (2.62) Max 67.26 (5.47) Min 55.4 (12.13) Total 11.86 (9.60) -4.43 (5.77) -13.71 (6.12) 9.27 (4.06) 59.77 (12.18) 6.75 (3.75) 53.02 (12.94) 0.70 (4.65) -12.51 (7.12) 13.21 (6.44) 3.49 (3.91) -2.71 (3.92) 6.19 (3.72) 25.41 (10.15) 24.80 (6.82) 24.80 (6.82) -4.65 (3.83) -13.74 (6.57) 9.09 (5.32) -5.91 (4.59) -14.23 (5.73) 8.32 (4.20) 71.59 (12.73) 6.39 (2.42) 65.21 (13.34) 2.14 (6.93) -1.64 (7.38) 3.77 (2.17) 11.64 (3.78) 11.99 27.39 (5.99) * (8.19) 1.65 (4.70) 10.35 (4.61) -1.83 (4.33) -6.66 (5.03) 4.83 (2.46) 60.27 (7.17) 28.45 (10.25) 31.83 (7.44) 7.65 (7.68) -4.62 (4.29) 12.27 (5.01) 13.59 (6.32) 61.62 (6.23) 25.13 (7.75) 3.05 (8.02) -1.46 (8.8) 4.51 (2.56) 16.71 (5.63) 12.09 (6.69) 4.62 (3.72) -1.23 (5.16) -3.82 (5.74) 2.60 (1.65) 58.93 (6.69) 48.35 (8.76) 10.57 (7.52) 11.88 (5.3) 7.00 (5.96) 4.88 (3.32) -4.65 (5.26) 14.26 (5.26) -8.65 (5.57) -11.49-12.41 (5.98) * (5.23) 6.83 3.76 (4.23) (2.74) 100.69 (3.93) 63.33 (4.71) 37.36 (6.60) 95.04 (4.87) 67.02 (6.51) 57.27 (10.15) 9.74 (7.84) 2.46 (8.06) -4.07 (8.49) 6.53 (2.63) 13.39 (7.37) -11.61 (8.06) 25.00 (10.55) 4.13 (4.86) -2.80 (4.47) 6.93 (4.17) 2.42 (11.37) 45.20 (12.43) 25.31 (10.30) 11.10 (5.57) -12.04 (7.60) 23.14 (10.39) -4.32 (6.84) -14.60 (8.22) 10.28 (5.48) 58.12 (10.00) 8.78 (9.68) 49.34 (14.15) 2.12 (8.28) -4.26 (8.63) 6.38 (2.89) 2.51 (5.56) -13.67 (6.12) 16.18 (7.72) 2.53 (5.26) -2.59 (4.88) 5.13 (2.89) 25.31 (10.30) -2.20 (5.17) 27.51 (10.06) -4.47 (5.26) -15.12 (6.00) 10.65 (7.48) -8.25 (6.18) -15.82 (8.79) 7.57 (4.58) 68.09 (17.26) 6.41 (3.84) 61.69 (18.37) 3.06 (9.45) -1.52 (9.61) 4.58 (2.27) 16.06 (6.23) 3.24 (5.31) 12.82 (4.55) -0.46 (4.43) -5.84 (4.52) 5.38 (2.53) 59.13 (10.29) 26.97 (10.21) 32.16 (10.60) 8.62 (6.22) -4.46 (4.09) 13.09 (5.22) -7.93 (4.98) -15.38 (5.81) 7.45 (4.34) 99.85 (4.8) 60.12 (13.34) 39.73 (13.48) 10.58 (2.74) 32.23 (7.9) 12.39 (5.28) 63.92 (7.87) 27.70 (9.37) 15.50 (5.3) 93.98 (5.55) DS1: double limb support 1 (weight acceptance to pull up), SS: single limb support (pull up to forward continuance), DS2: double limb support 2 (forward continuance to foot clearance), SW: swing phase (foot clearance to foot placement). * p<0.05 than control group. 16 www.kptjournal.org

Stair Kinematics in People with Genu Varum lowering, 흔듦기동안 (4) leg pull through, (5) foot placement 등의세부주기를가진다. 21 본연구에서는보행주기의명확한구분을위하여발뒤꿈치닿기 (heel strike, HS) 와발가락떼기 (toe off, TO) 와같은과정 (event) 를기준으로크게두다리지지기 (double limb support, DS), 한다리지지기 (single limb support, SS) 및흔듦기 (swing phase, SW) 로구분하여분석하였으며, 오른쪽발의발뒤꿈치닿기부터왼쪽발의발가락 떼기까지를첫번째두다리지지기 (DS1), 왼쪽발의발뒤꿈치닿기까지를한다리지지기 (SS), 오른발발가락떼기까지를두번째두다리지지기 (DS2), 오른발발뒤꿈치닿기까지를흔듦기 (SW) 로구분하였다. 계단보행주기와비교해보면, 본연구에서구분한주기는계단보행의각주기사이의기간을의미한다. 즉, 계단오르기에서 weight acceptance와 pull up 사이의기간이첫번째두다리지지기가됨을의미한다. Table 3. Stair descent pelvic, hip and knee maximum, minimum and total kinematics in sagittal, frontal and transverse plane in people with genu varum compared to control. Stair Descent Varus (n=20) Control (n=20) DS1 SS DS2 SW Total DS1 SS DS2 SW Total Pelvic kinematics ( ) Frontal plane Transverse plane Hip kinematics ( ) Frontal plane Transverse plane Knee kinematics ( ) Max 11.54 (4.19) Min 8.18 (4.04) Total 3.37 (1.71) Max -0.13 (3.05) Min -6.03 (2.27) Total 5.9 (2.41) Max 4.28 (5.28) Min -1.01 (4.22) Total 5.30 (2.98) Max 21.43 (5.91) Min 11.58 (7.61) Total 9.85 (3.62) Max -3.52 (4.47) Min -10.19 (4.24) Total 6.67 (1.76) Max -9.03 (6.35) Min -17.53 (6.82) Total 8.5 (2.9) Max 17.62 (8.59) Min 2.72 (4.77) Total 14.9 (6.62) 11.10 (3.38) 7.98 (3.72) 3.12 (1.81) 10.5 (3.55) 7.50 (3.90) 3.01 (1.24) 1.23 (2.87) 6.55 (2.07) -5.65 1.54 (2.86) (2.66) 6.88 (2.13) * (2.67) 2.81 (5.80) -3.14 (4.27) 5.95 (5.07) 14.84 (8.75) 6.33 (7.83) 8.51 (3.76) 3.44 (4.61) -4.7 (4.68) 8.14 (3.85) -4.52 (6.67) -12.45 (7.35) 7.94 (4.07) 42.13 (13.49) 13.8 (8) 28.33 (12.39) -1.10 (4.57) -5.36 (4.10) 4.26 (1.99) 23.05 (8.95) 11.77 (4.77) 11.77 (4.77) 6.73 (3.88) -0.44 (4.93) 7.17 (2.56) -2.01 (4.84) -6.98 (5.16) 4.97 (2.34) 94.51 (9.17) 44.87 (13.54) 49.64 (14.5) 10.52 (4.48) 7.26 (4.12) 3.26 (2.28) 5.48 (3.09) -3.80 (2.67) 9.28 (2.79) 2.68 (3.63) -3.4 (4.42) 6.08 (4.04) 33.49 (7.69) 15.79 (6.84) 17.70 (3.85) 1.14 (5.08) -7.89 (3.34) 9.03 (4.24) -1.67 (4.14) -11.55 (4.92) 9.88 (4.42) 99.57 (6.49) 2.32 (6.16) 97.25 (6.77) 6.4 (2.28) 14.23 (3.64) 11.48 (5.76) 27.20 (4.78) 17.71 (4.86) 17.62 (5.21) 10.91 (3.85) 8.28 (3.62) 2.64 (1.49) -1.62 (3.51) -7.36 (3.52) 5.74 (1.83) 4.78 (4.34) 0.15 (4.28) 5.03 (1.90) 21.73 (4.9) 12.15 (6.23) 9.58 (3.30) -2.99 (3.87) -9.43 (3.83) 6.43 (1.82) -7.52 (8.94) -15.49 (8.73) 7.97 (3.45) 98.78 16.17 (5.99) * (6.81) 4.6 (3.55) 11.58 (5.55) 10.78 (3.92) 7.34 (3.45) 3.43 (2.00) 2.25 (2.98) -7.00 (3.18) 9.25 (2.98) 2.48 (4.40) -4.04 (4.87) 6.52 (2.84) 5.04 (5.08) 8.99 (3.44) 23.96 (5.64) 5.19 (3.78) -4.51 (3.99) 9.7 (3.85) -4.29 (6.69) -11.65 (6.85) 7.36 (2.22) 42.25 (8.63) 12.89 (6.24) 29.36 (8.47) 10.22 (3.46) 7.42 (3.42) 2.81 (1.24) 7.48 (2.76) 2.47 (2.45) 5.01 (2.11) -1.24 (3.97) -6.01 (4.19) 4.77 (2.36) 23.96 (5.64) 11.39 (4.91) 12.57 (4.27) 8.37 (4.54) 0.96 (3.56) 7.41 (2.47) -3.12 (4.13) -8.08 (4.52) 4.96 (3.22) 93.43 (5.69) 45.51 (8.11) 47.92 (9.62) 9.86 (3.52) 6.60 (3.73) 3.26 (1.66) 5.33 (2.21) -5.4 (2.38) 10.73 (3.69) 4.62 (2.93) -2.76 (4.02) 7.38 (3.15) 33.41 (6.17) 16.54 (5.25) 16.88 (4.32) 2.48 (3.96) -7.73 (3.98) 10.2 (4.09) -3.34 (4.97) -13.98 (6.79) 10.64 (4.71) 97 (5.92) 4.38 (4.15) 92.62 (7.9) 6.03 (2.03) 16.31 (5.16) 13.09 (4.67) 28.37 (4.3) 18.81 (5.64) 15.77 (4.52) 94.16 (6.99) DS1: double limb support 1 (weight acceptance to forward continuance), SS: single limb support (forward continuance to controlled lowering), DS2: double limb support 2 (controlled lowering to leg pull through), SW: swing phase (leg pull through to Foot placement). * p<0.05 than control group. www.kptjournal.org 17

The Journal of Korean Physical Therapy Yun-Won Chae, et al. 3) 실험절차계단보행시다리의운동형상학을측정하기위해삼차원동작분석장비 (motion analysis, CA, USA) 를사용하였으며, 11대의운동포착 (motion capture) 카메라를통해다리분절에대한위치정보를수집하였다. Cortex motion capture software 1.1.4.386 프로그램을이용하여 1초당 120 프레임의속도로데이터를수집하였으며, 지름 9.5 mm 크기의반사표식자 (marker) 는 Helen-hayes marker set 방법으로다음의부위에부착하였다 ; 앞위엉덩뼈가시 (anterior superior iliac spine, ASIS), 뒤위엉덩뼈가시 (posterior superior iliac spine, PSIS), 엉치뼈 (sacrum), 허벅지 (thigh), 안쪽관절융기 (medial condyle), 가쪽관절융기 (lateral condyle), 정강이 (shank), 안쪽복사뼈 (medial malleolus), 가쪽복사뼈 (lateral malleolus), 발뒤꿈치 (posterior calcaneus), 다섯째발허리뼈머리 (5th metatarsal head), 둘째와셋째발가락 (toe) 사이. 엉치뼈를제외한나머지부위는양쪽으로부착하였으며, 총 21개의표식자를이용하였다. 22 삼차원동작분석을위한표식자를피험자의몸에부착한후, 피험자가계단보행시자연스러운보행을할수있도록사전에충분히연습하도록하였다. 3단으로된계단보행중오른발을먼저내딛도록하였으며, 계단보행의연속된동작을분석하기위하여오른발이두번째계단에놓이게되는첫발뒤꿈치닿기부터한주기를측정하였다. 다리의운동형상학은골반과엉덩관절의이마면, 시상면및가로면, 무릎관절의시상면의데이터를수집하였다. 4) 운동학데이터분석한보행주기 (100%) 동안의데이터는첫발뒤꿈치닿기를 0%, 다음발뒤꿈치닿기를 100%, 그리고 1% 의간격으로표준화 (normalization) 하였으며, 그룹별로각피험자들의앙상블평균 (ensemble average) 을구하여그래프로나타내었다 (Figure 1, 2). 23 또한, 앞서언급한보행주기별로최대각도 (maximum angle) 와최소각도 (minimum angle), 총관절가동범위 (total ROM) 을구하였으며, 두그룹간의차이를분석하였다 (Table 2, 3). 5) 통계분석두그룹의일반적인특성및운동학데이터를비교하기위하여독립 t 검정 (independent t-test) 을사용하였다. 통계처리는윈도우용 PASW version 18.0 을사용하였으며, 유의수준 (α) 은 0.05로하였다. 결과 1. 계단보행시관절운동형상학계단오르기동안두집단의다리관절운동형상학은이마면에서의골반의가쪽기울기 (lateral tilt), 엉덩관절모음 (hip adduction), 그리고 가로면에서의엉덩관절돌림 (hip rotation) 에서유의한차이가있었다 (Figure 1). 골반의가쪽기울기는보행주기 0% 부터 8% (p < 0.05) 까지초기디딤기기간과, 83% 부터 100% (p < 0.05) 까지마지막흔듦기에서차이를보였다. 엉덩관절모음역시보행주기 0% 에서 5% (p < 0.05) 까지초기디딤기기간에차이를보였으며, 엉덩관절돌림은 90% 에서 100% (p < 0.05) 까지마지막흔듦기에서차이를보였다. 계단내리기동안에는이마면에서의골반가쪽기울기와, 가로면에서의골반돌림 (pelvic rotation) 에서유의한차이가있었다 (Figure 2). 골반가쪽기울기는보행주기 11% 부터 17% (p < 0.05) 까지인초기디딤기기간과, 96% 부터 99% (p < 0.05) 까지의마지막흔듦기에서차이를보였으며, 골반돌림또한이와비슷하게 95% 부터 99% (p < 0.05) 까지마지막흔듦기에서유의한차이가있었다. 무릎관절에서는계단오르기와내리기모두통계학적으로유의한차이가없었다 (p > 0.05). 2. 계단보행주기별관절가동범위관절가동범위의경우계단오르기동안이마면에서의골반가쪽기울기, 엉덩관절모음및가로면에서의엉덩관절돌림에서두집단간유의한차이가있었다 (Table 2, Figure 1). 보행의초기두다리지지기에서안굽이무릎군은엉덩관절모음이감소되었다 (Figure 1E). 그리고보행의마지막구간인흔듦기동안에는골반을가쪽으로덜들어올렸으며, 이때엉덩관절의가쪽돌림또한충분하지않았다 (Figure 1B, 1F). 계단내리기동안에는이마면에서의골반가쪽기울기와, 시상면에서의무릎굽힘에서유의한차이가있었다 (Table 3, Figure 2). 계단내리기중한다리지지기 (SS) 동안골반가쪽기울기의관절가동범위가충분하지않았으며, 무릎의경우전체보행주기동안무릎굽힘관절가동범위가대조군에비해더컸다 (Figure 2B, 2G). 고찰본연구는안굽이무릎이계단보행시골반, 엉덩관절, 무릎관절의관절운동형상학에미치는영향을알아보았다. 안굽이무릎에대한보행연구는무릎관절과엉덩관절에국한되어있거나, 뼈관절염과관련된것이대부분이다. 7,10,19 골반에대한연구들은허리등의질환이나척추정렬등몸통과관련이되어있으며비교적다양한편이나, 골반의운동형상학에관한연구는극히제한적이었다. 24-30 따라서엉덩관절과무릎관절뿐만아니라골반의이마면, 시상면및가로면관절운동형상학에서분석함으로써다리의몸쪽관절에서나타나는안굽이무릎의영향에대해알아보고, 이운동형상학적변화가무릎관절에어떤영향을미치는지연구하였다. 운동형상학적변화는앙상블평균을통해 100% 로표준화하였으며, 1% 간격의데이터를매시점마다비교하여차이를알아보았다. 23 18 www.kptjournal.org

Stair Kinematics in People with Genu Varum A B C D E F G Figure 1. Stair ascent average pelvic (top), knee (middle), and knee (lower) kinematics for sagittal (left), frontal (middle), transverse (right) planes for genu varum (solid line) and control (dotted line) groups. The positive values mean A: pelvic forward tilt, B: pelvic rise, C: pelvic internal rotation, D: hip flexion, E: hip adduction, F: hip internal rotation, G: knee flexion. (DS1: double limb support 1, SS: single limb support, DS2: double limb support 2, SW: swing phase) A B C D E F G Figure 2. Stair descent ensemble average pelvic (top), knee (middle), and knee (lower) kinematics for sagittal (left), frontal (middle), transverse (right) planes for genu varum (solid line) and control (dotted line) groups. The positive values mean A: pelvic forward tilt, B: pelvic rise, C: pelvic internal rotation, D: hip flexion, E: hip adduction, F: hip internal rotation, G: knee flexion. (DS1: double limb support 1, SS: single limb support, DS2: double limb support 2, SW: swing phase) www.kptjournal.org 19

The Journal of Korean Physical Therapy Yun-Won Chae, et al. 또한 4개의세부주기로나누어각주기에서나타나는최대, 최소각도와총관절가동범위를비교해보았다. 앙상블평균에서의차이는각도의차이뿐만아니라, 특정이벤트가발생하는시점에도유의한차이가있음을의미하는데, 유의한차이가나타난대부분의경우안굽이무릎에서지연되어있었음을알수있었다. 안굽이무릎의경우계단을오를때초기디딤기단계에서엉덩관절모음이감소했으며, 흔듦기동안골반기울기및엉덩관절가쪽돌림이감소한것으로나타났다 (Table 2, Figure 1B, 1E, 1F). 골반의가쪽기울기의경우초기디딤기기간동안최대및최소각도, 전체관절가동범위에서는차이가없었으나, 앙상블평균을비교한결과보행주기의 8% 까지유의하게감소한것으로나타났다. 오른발을첫계단에올린후이어지는두다리지지기동안골반은디딤발쪽으로상승하게되는데, 이때디딤발의안-가쪽위치에변화가없다면엉덩관절은상대적으로모음상태가된다. 안굽이무릎의경우이기간동안골반이충분히상승하지못했으며, 이는상대적으로엉덩관절모음의감소로나타난것으로보인다. 특히, 초기디딤기동안엉덩관절을좀더벌림상태로둠으로써지지면 (base of support, BOS) 을확보하여안정성을향상시키고, 이때무릎관절의안쪽을지나는무릎모음모멘트를감소시켜안쪽무릎으로의하중을감소시키는데기여했을것이라사료된다. Bennett 등의연구 31 에서는안굽이무릎의경우계단보행시안짱다리 (toe-in) 와함께보폭을넓힘으로써무릎모음모멘트를감소시킨다고하였으며, Barrios 등의연구 32 에서는평지보행시엉덩관절모음이감소하였다고보고하여본연구와유사한결과를보였다. 엉덩관절벌림근은같은쪽다리가디딤기에있을경우엉덩관절모음과벌림을조절함으로써골반의가쪽기울기에도영향을미치게되는데, 33 엉덩관절벌림근이약화되면보행시반대쪽골반이떨어지면서같은쪽엉덩관절이모음상태가되는트렌델렌버그보행이나타나게된다. 젊은성인과비교했을때노인에게서이러한증가된엉덩관절모음현상이나타나게되는데, 34 본연구의피험자들은모두젊은성인을대상으로하였으므로노인에게서나타나는엉덩관절벌림약화로인한엉덩관절모음각도증가는나타나지않았다. 오히려반대쪽골반이대조군에비해상대적으로높은위치에있다는것은벌림근이과도하게수축하고있기때문일수있으며, 감소된엉덩관절모음각도는벌림근의지레길이를단축시켜불충분한근력을발생시킬수있는데, 이는장기적으로벌림근의약화를초래할수있다. 한편, 기존연구에서는엉덩관절뼈관절염환자에서디딤기동안엉덩관절모음에감소를보였다. 35 계단오르기동안흔듦기에서도일부관절운동형상학에차이를보였는데, 안굽이무릎의경우다음계단으로다리를이동시키는과정에서골반이충분히상승하지못했으며, 동시에엉덩관절가쪽돌림이감소되어있었다. 엉덩관절굽힘상태에서안쪽돌림에관여하 는근육은엉덩관절벌림근으로, 디딤기에서와마찬가지로엉덩관절가쪽돌림의감소는벌림근이효율적으로근력을발생시키기위한충분한길이로늘어나는것을방해하는요인이되며, 장기적으로벌림근단축및약화를발생시킬수있다. 밖굽이무릎의경우무릎의가쪽돌림을감소시키고, 엉덩관절가쪽돌림을증가시킴으로써관절의부하를감소시키는보행의보상패턴을보였는데, 36 이처럼가로면에서의엉덩관절각도의감소는무릎관절의부하를감소시키는기전으로작용할수있을것이다. 계단내리기초기디딤기동안골반은반대쪽골반에비해상대적으로떨어지게되는데, 이때안굽이무릎의경우골반하강이충분하지않았다. 골반의가쪽기울기를결정하는근육은엉덩관절벌림근이주요근육으로, 계단을오를때와마찬가지로벌림근의과도한수축상태가계단내리기에서도유지되는것으로보인다. 한다리지지기는반대쪽다리가디딤발보다높은계단에서더낮은계단으로이동하는시기이므로골반의수평높이또한큰변화를보이는데, 이때안굽이무릎의경우이마면에서의골반의관절가동범위가충분하지않은것으로나타났다. 이또한벌림근의과도한수축이골반을상대적으로중립에위치시킨것이라예측할수있다. 후기흔듦기동안골반은이마면상에서충분히떨어지지않았으며, 골반의안쪽돌림또한충분히이루어지지않았다. 두움직임모두보행주기마지막 5% 단계에서감소를보였는데, 골반의하강및안쪽돌림은계단을내려갈때흔듦기상태의발을앞으로전진하는과정에서중요한골반움직임이라할수있으며, 이러한골반의불충분한움직임은움직임에관여하는근육들의비효율적인수축을야기할것이라생각된다. 계단내리기동안시상면에서의무릎관절가동범위는정상정렬을가진사람들에비해안굽이무릎군에서증가한것으로나타났다. 이는골반에서나타나는불충분한각도를보상하기위해무릎굽힘각도를증가시킨것으로보인다. 청소년기안굽이무릎의운동형상학에대해보고한기존연구 10 에서는안굽이무릎의평지보행시무릎의폄각도가감소했다고보고했으며, 젊은성인의안굽이무릎변형에대한또다른연구 34 에서는평지보행시중간디딤기 (midstance) 동안무릎굽힘각도가증가했음을밝혔는데, 상반된결과를보인두연구 10,34 는대상자의연령이일치하지않거나평지보행에서진행되었다는점에서본연구와직접적인비교는불가능하지만, 이마면에서의다리부정정렬인안굽이무릎이무릎의시상면운동형상학에영향을미친다는사실은일치한다. 특히본연구와대상자연령이비슷한후자의연구 35 는무릎굽힘각도가증가했음을보고함에따라본연구결과를뒷받침해주고있다. 무릎관절에서와는달리, 엉덩관절에서는두그룹간에유의한차이를보이지않았다. 안굽이무릎의경우부하지지축이무릎관절의안쪽을지나게되는 20 www.kptjournal.org

Stair Kinematics in People with Genu Varum 데, 이로인해무릎모음모멘트가증가하게되어안쪽구획뼈관절염을유발시키게된다. 이러한구조적변형은무릎관절을지나는근육들의상태에도영향을미치는데, 중간볼기근 (gluteus medius) 과같은엉덩관절벌림근은상대적으로단축되어있거나긴장상태에놓이게된다. 안굽이무릎과관련이있는안쪽무릎뼈관절염에대한골반의기하학연구 15 에서는넙다리뼈목-몸통각도 (femoral neck-shaft angle) 가안굽이형태로변형됨과동시에엉덩관절벌림각도가감소되어있었으며, 이또한벌림근의길이-장력관계에영향을미칠수있음을알수있다. 본연구에서는벌림근에대한근전도분석은실시하지않았으나, 벌림근의과도한수축으로인해발생할수있는운동형상학의변화를추측할수있었다. 이러한벌림근의과도한수축은장기적으로근육의단축및약화를초래할수있으며, 이는무릎관절뼈관절염환자에게흔히나타나는현상이므로적절한대처가필요하다. 따라서벌림근의효과적인재활을위한연구가진행되고있다. 37 본연구결과이마면에서의골반운동형상학에서가장큰그룹간차이를보였다. 다리정렬과엉덩관절과의관계를증명한기존연구 16에서는엉덩관절중심과발목관절중심을연결한역학적축 (mechanical axis) 이무릎관절에서멀어질수록알파-각또한큰값을가진다고보고하였는데, 이알파-각은넙다리절구부딪힘증후군의발병유무를결정짓는요인으로, 안굽이무릎이나밖굽이무릎이엉덩관절에서발생하는역학적질환과도관련이있음을의미한다. 수술전이나대조군에비해정강뼈몸쪽뼈자름술집단에서더많은확률로 cam 변형을가진것으로보고한또다른연구 17 에서는안굽이정강뼈가있을경우 cam 변형을더많이가진다고하였으므로, 안굽이무릎과넙다리절구부딪힘증후군과의관계를직접적으로보여준다. 청소년기축구와같은충격이큰운동은안굽이무릎의발생을초래하는데, 11 넙다리절구부딪힘증후군또한활동성이높은젊은성인에게서호발하며넙다리절구부딪힘증후군과같은엉덩관절의구조적변형은젊은성인의엉덩관절뼈관절염에대한강력한예측인자이므로, 13 넙다리절구부딪힘증후군을포함한엉덩관절의구조적질환과안굽이무릎과의관련성을쉽게추측해볼수있다. 넙다리절구부딪힘증후군환자의경우계단보행시주로시상면과가로면에서관절운동제한을보였는데, 향후안굽이무릎변형을동반할경우이마면에서의관절운동형상학에어떠한영향을미치는가에대한연구가추가로필요할것이라생각된다. 무릎관절의경우시상면에서의운동형상학만분석한것은본연구의첫번째제한점이다. 하지만안굽이무릎에대한연구대부분은무릎관절의안-가쪽움직임, 이완, 또는이마면에서의관절이동에관한것이며, 가로면에서의움직임에관한연구 7 도일부진행되었다. 따라서본연구에서는다른연구에서진행하지않은시상면에서의무릎관절운동형상학을포함하여골반과엉덩관절의운동형상학 에더욱중점을두고자하였다. 두번째제한점은기존연구에서제시 된골반기하학및운동형상학에대한남녀차이를고려하지않았다 는점이다. 정강넙다리뼈관절염을가진남녀의골반차이는크기와 형태뿐만아니라, 엉덩관절의기하학및운동형상학에도괄목할만 한차이가있었다. 15,24 안굽이무릎변형을가진피험자들을대상으로 한또다른연구 32 에서는남녀사이에골반과엉덩관절의운동형상 학에도유의한차이를보고하였는데, 이또한남녀의구조적차이로 인한것으로보인다. 향후연구에서는성별에따른운동형상학의차 이를연구해볼필요가있을것이다. 향후연구에서는계단보행시안굽이무릎변형이엉덩관절의운 동역학에어떤영향을미치는지알아보고, 동시에엉덩관절주위근 육의근활성도를측정해봄으로써관절의변형이나역학적질환을 유발시킬수있는특정부위로의과부하를감소시키거나예방하기 위한적절한대안을찾을방안을마련할필요가있을것이다. 또한이 러한다리정렬의영향으로인한비정상적인근육활동을개선시킬 수있는보행패턴의변화, 또는재활훈련의방안또한제시되어야할 것이다. 본관절운동형상학연구는다리부정정렬로인한과도한부하로 관절의손상등을유발시킬수있는생체역학적위험요소들을확인 할수있었다. 특히, 이마면에서의무릎관절변형으로여겨지던안굽 이무릎변형이엉덩관절과골반의운동학에영향을미치며, 이는향 후다른엉덩관절질환의발병에도영향을미칠수있음을시사한다. 이러한발견은계단보행의생체역학에대한안굽이무릎의영향에 대한이해를돕고, 보존적재활을최적화시키기위해임상가와연구 가들에게도움이될것이라생각된다. 또한, 하지정렬이특정관절의 변형뿐만아니라다리전반에걸쳐발생할수있는역학적질환에대 한기초연구로본연구가활용될수있을것이라생각된다. Acknowledgements 이논문은 2017 년도광주보건대학교내연구비의지원을받아수행된 연구임 (No. 3017009). 참고문헌 1. Sharma LJ, Song J, Felson DT et al. The role of knee alignment in disease progression and functional decline in knee osteoarthritis. JAMA. 2001; 288(2):188-95. 2. Bezerra MJCB, Barbosa IM, Sousa TG et al. Profile of patients receiving total knee arthroplasty: a cross-sectional study. Acta Ortop Bras. 2017; 25(5):202-5. 3. Scouten JSAG, van den Ouweland FA, Valkenburg HA. A 12 year follow up study in the general population on prognostic factors of cartilage loss www.kptjournal.org 21

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