• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.19-31
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• 2006

이 연구의 목적은 각 분절의 마커세트와 무릎관절 중심 정의가 3차원 무릎 관절각을 산출하는데 얼마나 민감하게 영향을 미치는지를 연구하였다. 자료수집은 1명을 실험대상자로 하여 두 가지 형태의 각기 다른 분절의 정의와 무릎관절의 중심을 나타내는 반사마커들을 동시에 오른쪽 하지에 부착시켜 실험을 실시하였다. 실험대상자의 달리기동작 중 좌측으로 45도 방향전환동작의 지지기를 분석하였다. 이를 위해서 8대의 고속카메라들을 이용하였고 달리기속도는 4m/$sec{\pm}(10%)$로 통제하였다. 하지분절의 발분절에는 하나의 마커세트를, 정강이와 대퇴분절에는 두 가지의 다른 마커세트들을 부착시켰다. 발분절에는 3개의 마커를 신발의 뒷부분에 부착하였고 정강이분절을 정의하기 위하여 첫 번째 마커세트는 경골을 중심으로 3개의 마커들을 두 번째 마커세트는 비골을 중심으로 3개의 마커를 부착하였다. 대퇴분절의 마커세트를 정의하기 위하여 첫 번째 마커세트에는 대퇴골을 중심으로 3개의 마커를 두 번째 마커세트에는 대퇴근육을 중심으로 3개의 마커들을 부착하였다. 무릎관절중심을 정의하는데 두 가지 다른 정의가 적용되었다. 첫 번째 무릎중심을 무릎의 내측과 외측의 마커들을 통해 두 마커의 중심을 무릎관절의 중심으로 정의하였다. 두 번째 무릎중심정의는 무릎의 외측부분과 슬개골의 중심에 부착된 마커들로부터의 교차점을 무릎관절중심으로 산출하였다. 무릎관절의 각도를 산출하기 위해서 JCS(Joint Coordinate System)의 정의가 적용되었고 연구의 결과는 다음과 같았다. 두 가지의 다른 분절마커세트 사이에서 무릎의 신전(extension)과 굴곡(flexion)은 유사한 형태를 나타냈으며 최대 무릎굴곡(peak knee flexion)각에서 $4.746^{\circ}$의 차이를 나타냈다. 다른 분절마커세트 사이의 회전(rotation)각과 내전(adduction)/외전(abduction)에서는 서로 다른 형태를 나타내었고, 두 마커세트간 최대무릎외측회전(peak knee external rotation)각도에서는 $15.628^{\circ}$의 차이를 나타냈다. 또한, 각 분절마커세트 내에서 두 가지의 다른 무릎관절 중심의 정의가 얼마나 무릎도 산출에 영향을 미치는지를 비교했을 때 무릎의 최대외측회전(peak external rotation)각에서 차이를 나타내었다. 첫 번째 분절마커세트의 무릎관절중심정의의 형태변화에 따라 최대외측회전각은 $0.549^{\circ}$의 차이를 나타냈고, 두 번째 분절마커 세트에서 무릎관절중심정의의 형태변화에 따라 최대외측회전각은 $0.309^{\circ}$의 차이를 나타냈다. 이와 같이 분절을 나타내는 마커세트와 무릎관절중심정의의 형태변화에 따라 무릎간을 계산하는데 있어서 결과가 다르게 산출되었다. 즉, 관절각의 계산이 분절에 부착되는 마커의 정의 혹은 위치에 매우 민감하게 영향을 받았다. 따라서 연구자가 여러 실험대상자들을 대상으로 실험시 마커세트 혹은 마커들을 동일한 위치에 가깝게 부착하는 것이 마커부착으로부터 발생하는 실험오차를 줄일 수 있을 것이다.

• Journal of the Korean Arthroscopy Society
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• v.5 no.2
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• pp.104-110
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• 2001

Purpose : To analyze the patterns of osteochondral fracture associated with patellar dislocation and to assess the results of arthroscopic treatment. Materials and Methods : Fourteen patients were treated from March, 1989 to April, 1998 for patellar dislocations with osteochondral fracture. The average follow-up was 32 months. All were treated by arthroscopic procedures. The location and size of the fracture fragments were recorded. To assess the functional results, we used Larsen & Lauridson's score system. Results : Osteochondral fractures were found 8 cases in medial side of patella, 1 case in lateral side of patella, 5 cases in lateral margin of lateral femoral condyle. The range of maximal diameter of osteochondral fragment was from 1cm to 4.2cm. Treatments include fragment excision only in 6 cases, excision and medial retinacular repair in 2 cases, excision and medial retinacular repair and lateral retinacular release in 3 cases, and internal fixation only in 3 cases. The functional results were excellent in 5 cases$(36\%)$. good in 6 cases$(43\%)$, fair in 1 case$(7\%)$ and poor in 2 cases$(14\%)$. Conclusion : In osteochondral fractures associated with patellar dislocation, arthroscopic treatment is useful to diagnose precisely, to determine proper treatment modality, and to minimize the complications.

• Journal of the Korean Society of Radiology
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• v.8 no.2
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• pp.57-63
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• 2014

This study aims to find out the standardized test criteria regarding patients with the anterior cruciate ligament damage by identifying the degree of the flexion gap of femur and tibia upon bending of the anterior cruciate ligament in order to carry out the accurate test of such impairment. On the standardized test method and judgement criteria upon the anterior cruciate ligament test using Telos, it has been shown that there was no significant difference in the results according to the position of a fixed roller in the anterior cruciate ligament test for normal patients. However, in a test for patients who had undergone the anterior cruciate ligament reconstruction, it has been shown that the measured values of the anterior cruciate ligament tended to be pushed when the position of a fixed roller was less than 1cm in the test according to the position of a fixed roller of Telos (less than 1cm, more than 3cm), and this was statistically significant. The anterior cruciate ligament test (knee stress test) is a limited method used in orthopedics and rehabilitation medicine, and there have been no standardized test guidelines available yet although numerous ligament measurement tests have been performed. In addition, since the measured values are often different depending on testers even on the test that is expected to give the same result, the reproducibility of the test is still low. Accordingly, it is considered that the criteria for the anterior cruciate ligament test need to be established, and this would contribute to the accuracy of the diagnosis through the accurate test and standardized measurements.

• Journal of the Korean Orthopaedic Association
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• v.54 no.5
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• pp.427-434
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• 2019

Purpose: This study evaluated the long term clinical and radiographic results and the survival rates of unicompartmental knee arthroplasty (UKA). In addition, the factors affecting the survival of the procedure were analyzed and the survival curve was compared according to the affecting factors. Materials and Methods: Ninety-nine cases of UKA performed between December 1982 and January 1996 were involved: 10 cases with Modular II, 44 cases with Microloc, and 45 cases with Allegretto prostheses. The mean follow-up period was 16.5 years. Clinically, the hospital for special surgery (HSS) scoring system and the range of motion (ROM) were evaluated. Radiographically, the femorotibial angle (FTA) was measured. The survival rate was analyzed using the Kaplan-Meier method. Cox regression analysis was used to identify the factors affecting the survival according to age, sex, body mass index, preoperative diagnosis, and type of implant. The Kaplan-Meier survival curves were compared according to the factors affecting the survival of UKA. Results: The overall average HSS score and ROM was 57.7 and 134.3° preoperatively, 92.7 and 138.4° at 1 year postoperatively, and 79.1 and 138.4° at the last follow-up (p<0.001, respectively). The overall average FTA was varus 0.8° preoperatively, valgus 4.1° at postoperative 2 weeks, and valgus 3.0° at the last follow-up. The overall 5-, 10-, 15- and 20-year survival rates were 91.8%, 82.9%, 71.0%, and 67.0%, respectively. The factors affecting the survival were the age and type of implant. The risk of the failure decreased with age (hazard ratio=0.933). The Microloc group was more hazardous than the other prostheses (hazard ratio=0.202, 0.430, respectively). The survival curve in the patients below 60 years of age was significantly lower than those of the patients over 60 years of age (p=0.003); the survival curve of the Microloc group was lower compared to the Modular II and Allegretto groups (p=0.025). Conclusion: The long-term clinical and radiographic results and survival of UKA using old fixed bearing prostheses were satisfactory. The selection of appropriate patient and prosthesis will be important for the long term survival of the UKA procedure.

• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.2
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• pp.76-82
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• 2009

Purpose: The purpose of this study was to analyze the clinical result and the gait patterns for patients who had undergone the arthroscopic posterior cruciate ligament (PCL) reconstruction using Achilles allograft. Materials and Methods: Among the patient who had undergone the arthroscopic PCL reconstruction using fresh-frozen Achilles allograft between March 2004 to March 2005, we selected 12 patients who compliance to our rehabilitation program. Clinical result and gait analysis were carried out at 36 months postoperatively. There were measured by using range of motion (ROM), Lysholm knee score, Tegner activity score, IKDC score, posterior stress test, and posterior translation measured by using Telos stress arthrometer. Kinematic gait analysis was carried out using 3-dimensional gait analysis system. Results: The PCL reconstruction surgery yielded statistacally significant results in all of clinical evaluation. In gait analysis, the average knee flexion angle increased during stance phase and decreased during the swing phase, but was not statistically significant and there were no significant difference between both sides of their knees overall. Conclusion: Since there was no statistically significant difference between the injured and uninjured sides as a result of the gait evaluation of the patients who had arthroscopic reconstruction surgery on their PCL injured knee and conformed to the rehabilitation program, systemic and strict rehabilitation ought to be important in the reconstruction surgery.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.205-215
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• 2009

The purpose of this study is to investigate alterations of pregnant gait by means of 3 different treads of stairs. 9 subjects(body masses; $59.41{\pm}7.49$, $64.03{\pm}6.65$, $67.26{\pm}7.58$, heights; $160.50{\pm}6.35$ ages; $31.22{\pm}2.99$; parity; $1.67{\pm}0.71$) participated in three experiments that were divided by physiological symptoms(the early(0-15 weeks), middle(16-27 weeks) and last(18-39 weeks), and walked at self-selected pace on 4 staircases 3 trials. As extending the pregnancy period, cadence was shorter but cycle time was longer more and more and the difference of maximum and minmum moments between right and left knee joint moment was smaller. With the treads of stair decent lengthening, speed and stride lengths were increased. As extending the treads of stair decent, joint moments of both feet were particular traits, hip joint was asymmetric but joint moments of knee and ankle were symmetric. These findings may account for relation between the treads of stair and moments and suggest that women may adapt their gait to maximize stability and to control gait motion for themselves in pregnant women.

• Journal of the Korean Arthroscopy Society
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• v.10 no.1
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• pp.61-69
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• 2006

Purpose: Open lateral release and complete lateral release have been conducted as a surgical method in patients with patellofemoral malalignment. But authors sought to find out the best method by conducting selective release, with minimal excision of the involved lesion, and comparative analyzing the result, as postoperative satisfaction and complication. Materials and Methods: Over the 68 patients of 90 cases who underwent arthroscopic release, among 94 patients of 129 cases who underwent lateral retinacular release, from January 1993 to June 1998 were followed up prospectively. A radiological evaluation of patellar inclination, patellar tilt, congruence angle, and Q-angle and a clinical evaluation of HSS-Knee score and modified patellar score were used for analysis data before operation and data at 1 year and 5 year after operation. Results: According to the radiologic evaluation, the patellar tilt and translation revealed improvement of the results, from $13.4^{\circ}$ and 12.1mm to $3.6^{\circ}$ and 3.8mm with arthroscopic lateral complete release, and from $12.3^{\circ}$ and 11.2mm to $4.8^{\circ}$ and 5.2mm with selective release, and from $13.6^{\circ}$ and 12.3mm to $3.3^{\circ}$ and 3mm with open release. But they were not significantly related to the clinical results. HSS-Knee score was 84.2%(48/57), 81.8%(27/33), 82.1%(32/39) and modified patellar score was 82.5%(47/57), 81.8%(27/33), 82.1%(32/39) respectively, which revealed satisfactory results. And no significant difference among the operative methods were shown. Conclusion: Arthroscopic lateral retinacular release which is one of the surgical method for patellofemoral malalignment enhances rehabilitation and satisfaction of the patient, by releasing the involved retinaculum within lesser surgical extent, compared to open and complete lateral release without complications such as adhesion.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.435-448
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• 2009

The purpose of this study was to investigate the kinemaitc gait parameter of lower extremities with different gait conditions(level walking, stairs, ramp) in old adults. Fourteen healthy older adults participated in this study and kinematic data were measured using 3D motion analysis system(Vicon, Oxford Metrics, England). Statistical analysis was used one-way ANOVA to know the difference of lower extremities angle at each gait phase with a different gait conditions. In sagittal plane, pelvic anterior tilt increased in stairs and ramp climbing and hip and knee flexion increased in stairs climbing but ankle dorsiflexion increased in ramp climbing. In frontal plane, pelvic was up in stairs and hip abduction and adduction more changed in stairs climbing than level walking. Knee varus and ankle inversion increased in stair climbing. In horizontal plane, pelvic internal rotation increased in stairs and ramp climbing and knee internal rotation increased in stairs climbing but ankle external rotation increased in stairs climbing. This results was shown that the stairs and ramp climbing changed the kinematic gait parameters of lower extremities in healthy old adults.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.565-566
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• 2012

• Investigative Magnetic Resonance Imaging
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• v.3 no.1
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• pp.66-72
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• 1999

Purpose : To evaluate the usefulness of Dual Echo in Steady State(DESS) image in the diagnosis of chondromalacia of the knee compared with turbo spin-echo MR images Materials and Methods : We included 26 patients with chondromalacia of the knee. MR imaging was obtained with a 1.5T imager. Sagittal and coronal double echo T2 weighted images(TR/TE 3000-4200/16-96msec, FOV $140-160{\times}140-160mm$, matrix size $180{\times}256$, slice thickness 4.0mm, interslice gap 0.5mm), and sagittal DESS image(TR/TE 25.4/9.0msec, flip angle $35-45^{\circ}$, FOV $150-160{\times}150-160mm,{\;}matrix{\;}size{\;}192{\times}256$, effective slice thickness 1.5mm) were obtained. Cartilage lesions were staged according to a modified scheme proposed by Outerbirdge: grade 0, normal; grade 1, softening or/and swelling; grade 2, mild surface fibrillation or/and less than 50% of cartilage thickness; grade 3, severe surface fibrillation or/and loss of more than 50% of cartilage thickness but without exposure of subchondral bone; and grade 4, complete loss of cartilage with subchondral bone exposure. Gradings were determined by two readers with consensus, and patellofemoral, medial and lateral tibiofemoral compartments were evaluated. Results : Arthroscopic findings revealed grade 1 in seven cases, grade 2 in 21 cases, grade 3 in six cases, and grade 4 in 18 cases. Sensitivity of turbo spin-echo MR image was as follows; 0%, 14%, 0%, 61% in each grade, and sensitivity of DESS image was as follows; 0%, 33%, 50%, 67%, in each grade(p=0.001). In the detection of chondromalacic lesions regardless of gradings, sensitivity, specificity and accuracy of conventional MR image were 59.6% 88.6% 78.8%, and of DESS image, 73.1% 88.4%, 82.2%(p=0.007). Conclusion : For chondromalacia of knee joints, DESS images showed higher sensitivity than turbo spin-echo MR images. Therefore, DESS images will be helpful for diagnosis of chondromalacia of knee joints.