• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.7
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• pp.703-708
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• 2013

Conventional total hip joint replacement(THR) surgery requires a long incision and long rehabilitation time. The stem used in THR is inserted into the cancellous bone of the femur where it plays the role of the artificial joint. Minimally invasive surgery(MIS) has been devised to reduce muscle damage to patients. In this study, a mechanical stem was developed on the basis of MISto reduce the incision length through the principle of the gear. The mechanical stem consists of six components. A prototypical model for a mechanical stem was fabricated using an acryl-based polymer, and its workability was confirmed. To actualize the mechanical stem, a three-dimensional Bio-CAD modeling technique was applied. The hip joint area based on computed tomography(CT) was reconstructed. The safety of the mechanical stem by applying more load than the weight of a man under virtual surgery environment conditions was confirmed by finite element analysis.

• The Journal of Korea CHUNA Manual Medicine
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• v.5 no.1
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• pp.141-150
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• 2004

Objectives : The objective of this study is to evaluate the treatment effect of Oriental therapy including exercise therapy in chronic ankylosing spondylitis with total hip replacement. Methods : Oriental therapy and exercise therapy were performed for 64days admission in a patient who had chronic ankylosing spondylitis with total hip replacement and physical tests were examined. Result : Pain and ROM of cervical. lumbar spine, and left hip joint has improved with this treatment. And Anorexia, dyspepsia, and fatigue were also decreased. Conclusions: In this case, oriental therapy was proved to be effective in improving chronic symptoms and general prostration of Ankylosing Spondylitis. And It is necessary to carry out exercise therapy regulary.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1491-1492
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• 2011

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.28 no.1
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• pp.9-17
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• 2022

Background: Functional massage is a therapeutic massage that incorporates joint motion in non-end-range to reduce pain and improve range of motion (ROM) in patients. This study was aimed at investigating the immediate effect of functional massage on pain, range of motion, balance ability and, gait speed of patients having undergone total hip replacement. Methods: Twenty patients were treated by one participating orthopedic manual physical therapist and randomly assigned to the control group (n=10) or the experimental group (n=10). To treat patients of each group, functional massage and range of motion exercises were used. The experimental group received a functional massage and the control group received range of motion exercise for minutes for one session. The visual analog scale was used for pain assessment. Balance ability was measured using a timed up and go test and a one-leg standing test for patients. The 10-meter walk test was used for the measurement of gait speed assessment of patients. Results: Significant improvements were observed in terms of balance ability (p<.05), gait speed (p<.05), and ROM (p<.05) after functional massage. There was no significant inter-group difference (p>.05). Conclusion: Application of the functional massage showed that statistically significant improvements in ROM, gait speed, and balance ability after a single treatment session. This technique may be a useful treatment in patients having undergone total hip replacement.

• Journal of Biomedical Engineering Research
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• v.22 no.6
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• pp.519-526
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• 2001

At present. about 0.3 million and more THRs (Total Hip Replacement) in a rear are being done worldwide. The increase in mechanical failure with the increase in THR, required more revisions. Revisions compensate mainly the wear of the artificial joint frictional surface and the loosening of the cup and stem. According to recent researches, loosening is mainly due to wear debris UHMWPE (Ultra High Molecular Weight Polyethylene) from frictional surfaces . To overcome the wear problems associated with artificial joint materials , new surface structures with regular Patterns were designed and fabricated The lubrication Properties were examined to evaluate the wear of the frictional surfaces. The surface structure manifested a Pattern of "dents" with a 0.2-1.0 mm of diameter and 0.6-2.0 mm of Pitch. From the friction test of the SUS316L vs UHMWPE using the frictional tester, we found that the lubrication Performance was improved due to of drastically reduced amount of abrasion. There were optimum sizes for the diameter and the pitch of the Pattern. The results demonstrated that the lubrication properties could be improved by Patterning of the frictional surfaces. The surface Patterning was effective in preventing wear of the frictional surfaces, and the life of an artificial joint could be extended with such Patterning.

• Journal of the Korea Society of Computer and Information
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• v.28 no.12
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• pp.183-189
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• 2023

The propose of this study was to investigate the effects of squat exercise using a reformer on muscle strength, range of motion, and gait in hip joint replacement patients. This study was conducted on 20 patients hospitalized at a rehabilitation hospital in G City. As an intervention method, the experimental group performed squat exercises using a reformer, and the control group performed squat exercises, 7 times a week for 2 weeks. In the within-group comparison of the reformer group, there was a significant difference in hip flexion, extension, and abduction strength (p<0.05). There were significant differences within the group in the range of motion of hip extension and abduction and gait in the Reformer group (p<0.05). In comparison between groups, significant differences occurred in hip extension strength, hip extension, abduction range of motion, and gait (p<0.05).

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.365-366
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• 2002

The sliding wear behavior of ultra high molecular weight polyethylene (UHMWPE) was examined on a novel low temperature degradation-free zirconia/alumina composite material and conventional alumina and zirconia ceramics used for femoral head in total hip joint replacement. The wear of UHMWPE pins against these ceramic disks was evaluated by performing linear reciprocal sliding and repeat pass rotational sliding tests for one million cycles in bovine serum. The weight loss of polyethylene against the novel low temperature degradation-free zirconia/alumina composite disks was much less than those against conventional ceramics for all tests. The mean weight loss of the polyethylene pins was more io the linear reciprocal sliding test than in the repeal pass rotational sliding lest for all kinds of disk materials. Neither the coherent transfer film nor the surface damage was observed on the surface of the novel zirconia/alumina composite disks during the test. The observed r,'stilts indicated that the wear of the polyethylene was closely related to contacting materials and kinematic motions. In conclusion, the novel zirconia/alumina composite leads the least wear of polyethylene among the tested ceramics and demonstrates the potential as lhe alternative materials for femoral head in total hip joint replacement.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.117-117
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• 2016

Total ankle replacement (TAR) is a visible option in the surgical treatment of degenerative or inflammatory diseases of ankle joint. it is attributed to the current TAR which has improvements in surgical technique, uncemented implant fixation and minimally constrained articulation. In the clinical result, they can show promised surgical result when compared to earlier attempts in TAR. However, TAR is still not as successful as total knee replacement (TKR) or total hip replacement (THR), it needs to be note that there are limitations in concerning of long term performance of TAR, the high failure rate still associated with wear of the PE (polyethylene) component that has related with their material property and surface roughness. The aim of this study was to introduce the tribology characteristics of total ankle joint prosthesis with one of TDR model which was fabricated to try multi-axis wear test as a region of motion in ankle joint. The wear specimen of TDR was prepared with Ti-6Al-4V alloy and UHMWPE (ultra-high molecular weight polyethylene) for tibia-talus and bearing component, respectively. A wear test was carried out using a Force 5 (AMTI, Massachusetts, US) wear simulator which can be allowed to move in three axis to flexion-extension ($+3^{\circ}{\sim}-6^{\circ}$), internal-external axial rotation (${\pm}5^{\circ}$), as well as sinusoidal compressive load (1.6 kN, R=10). All tests were performed following standard ISO 14243, wear rate was calculated with weight loss of UHMWPE bearing while the specimen has tested at certain cycles. As based on the preliminary results, wear rate of UHMWPE bearing was $7.9{\times}10^{-6}mg/cycles$ ($R^2=0.86$), calculated loss weight until $10^7cycles$ was 79 mg, respectively.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.2
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• pp.17-28
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• 2024

PURPOSE: This study was conducted to investigate the effect of gluteal muscle strengthening exercises (GMSE) with ankle joint pumping exercises (AJPE) on thigh swelling, gait ability, and pain level in patients who underwent total hip arthroplasty. METHODS: A total of 38 patients who had undergone total hip replacement surgery >1 week prior participated in this study. Participants were randomly assigned to a group that performed only GMSE (CG; n = 19) and a group that performed GMSE and AJPE (EG; n = 19). The CG group performed GMSE for 30 min, and the EG group performed GMSE for 30 min followed by AJPE for 15 min. Exercises were performed five times a week, for a total of 20 times over 4 weeks in both groups. Thigh swelling (thigh size), 10 m walking test (10MWT) and timed up and go test (TUG) results, pain level (visual analogue scale, VAS) scores, Short Form 36 health survey (SF-36), and hip outcome scale (HOS) scores were evaluated before and after the intervention. RESULTS: After 4 weeks of intervention, significant differences were observed in the thigh size, 10MWT, TUG, VAS, SF-36, HOS before and after intervention in both groups (p < . 05). However, only thigh size showed a significant interaction between group and measurement time (p < . 05). CONCLUSION: GMSE combined with AJPE might be effective in improving the gait ability and pain level in patients with total hip arthroplasty, and GMSE may be more effective in improving thigh swelling and gait ability than GMSE without AJPE.

• PNF and Movement
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• v.20 no.2
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• pp.295-306
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• 2022

Purpose: This study aimed to investigate the effect of robot-assisted gait training on the active ranges of motion, gait abilities, and biomechanical characteristics of gait in patients who underwent lower extremity surgery, and to verify the effectiveness and clinical usefulness of robot-assisted gait training. Methods: This study was conducted on 14 subjects who underwent lower extremity surgery. The subjects participated in robot-assisted gait training for 2 weeks. The active ranges of motion of the lower extremities were evaluated, and gait abilities were assessed using 10-m and 2-min walk tests. An STT Systems Inertial Measurement Unit was used to collect data on biomechanical characteristics during gait. Spatiotemporal parameters were used to measure cadence, step length, and velocity, and kinematic parameters were used to measure hip and knee joint movement during gait. Results: Significant improvements in the active ranges of motion of the hip and knee joints (flexion, extension, abduction, and adduction) and in the 10-m and 2-min walk test results were observed after robot-assisted gait training (p < 0.05). In addition, biomechanical characteristics of gait, spatiotemporal factors (cadence, step length, and velocity), and kinematic factors (gait hip flexion-extension, internal rotation-external rotation angle, and knee joint flexion-extension) were also significantly improved (p < 0.05). Conclusion: The results of this study are of clinical importance as they demonstrate that robot-assisted gait training can be used as an effective intervention method for patients who have undergone lower extremity surgery. Furthermore, the findings of this study are clinically meaningful as they expand the scope of robot-assisted gait training, which is currently mainly applied to patients with central nervous system conditions.