• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.667-673
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• 2010

This paper proposes a control method based on a pseudo-impedance model to control the motion of biped robots walking on an uneven surface. The pseudo-impedance model simulates the action of the ankle of a foot landing on the ground when a human walks. When the foot is in contact with the ground, the human ankle goes through two different phases. In the first phase, the human exerts little or no effort and applies no torque on the ankle so that the orientation of the foot is effortlessly and passively adjusted with respect to the ground. In the second phase of landing, the ankle generates a significant amount of torque in order to rotate and move the main part of the human body forward and to support the weight of the human; this phase is called the weight acceptance phase. Computer simulations of a 12-DOF biped robot with a 6-DOF environment model were performed to determine the effectiveness of the proposed pseudo-impedance control. The simulation results show that stable locomotion can be achieved on an irregular surface by using the proposed model.

• Journal of Korean Foot and Ankle Society
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• v.15 no.2
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• pp.86-91
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• 2011

Purpose: To evaluate the effectiveness as well as correct the post-traumatic severe ankle equinus deformity by conducting the treatment surgery, which is divided into 2 stages, soft tissue adhesiolysis and ankle arthrodesis. Materials and Methods: We have conducted the methods, which are Z-plasty Achilles tendon lengthening, multiple capsulotomy and tendon lengthening (flexor hallucis longus muscle, flexor digitorum longus, posterior tibialis tendon) for 10 patients who has shown equinus deformity after post-traumatic compartment syndrome due to the injury. The average age of patients was 33.7 year-old; there were 8 men and 2 women, and the follow up period was 13 months (6~31 mon). Outcomes were rated based on American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, Visual Analogue Scale (VAS) and patient's satisfaction after operation. Results: The average degree of preoperative equinus deformity was 64 degree (-60~-70), and we've obtained AOFAS anklehindfoot score that was evaluated after 4 months of 2nd operation which was 76.7 score on average. We've also checked the decreased pain score from all of the patients according to the fact that the average VAS before the surgery was 6 (4~8), but it reduced to 3 (1~4). The patient's satisfaction showed generally great satisfactions which was 5 cases were excellent, 2 cases were good, and 3 cases were fair. Conclusion: The two staged surgical treatment of post -traumatic severe ankle equinus deformity, which was conducted of soft tissue adhesiolysis and arthrodesis, could be one of the effective methods to improve patients walking ability.

• Journal of Korean Foot and Ankle Society
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• v.21 no.2
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• pp.55-60
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• 2017

Purpose: Stiffness in the first metatarsophalangeal joint after surgery for hallux valgus has been reported. The goal of this study was to test the efficacy of releasing plantar aponeurosis for improving the range of extension in the first metatarsophalangeal joint that was limited after hallux valgus surgery. Materials and Methods: Thirteen patients (1 man, 12 women [17 feet]; median age, 54.4 years; range, 44~69 years) with limited first metatarsophalangeal joint extension after hallux valgus surgery, who underwent an additional procedure of plantar aponeurosis release between March 2015 and August 2015, were included. Subsequently, the passive range of extension in the first metatarsophalangeal joint was evaluated via knee extension and flexion positions. Hallux valgus angle, inter-metatarsal angle, distal metatarsal articular angle, and talo-first metatarsal angle were measured on weightbearing dorsoplantar and lateral radiographs of the foot preoperatively. Results: The mean range of extension for the first metatarsophalangeal joint improved significantly, from $2.5^{\circ}$ to $40.9^{\circ}$ in the knee extension position (p<0.00). The mean extension range for the first metatarsophalangeal joint also improved, from $18.2^{\circ}$ to $43.2^{\circ}$ in the knee flexion position (p<0.00). In all patients, congruence of the first metatarsophalangeal joint was recovered. Conclusion: Plantar aponeurosis release is an effective additional procedure for improving the extension range of the first metatarsophalangeal joint after hallux valgus surgery.

• Journal of Korean Foot and Ankle Society
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• v.18 no.4
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• pp.153-158
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• 2014

Purpose: The objective of this study was to examine the clinical results and effectiveness of resection arthroplasty for correction of lesser toe deformity. Materials and Methods: From January 2000 to November 2012, 92 cases of resection arthroplasty for lesser toe deformity were reviewed. Hammer toe was the most common type of deformity, accounting for 44 toes (33 patients). Hallux valgus was the most common comorbid illness. Second toe was the most commonly affected toe and proximal interphalangeal joint was the most common location of resection arthroplasty (69 toes, 75.0%). We also analyzed the alignment of phalanges using the last follow-up weight bearing radiographic image. The analysis included clinical evaluation with American Orthopaedic Foot and Ankle Society (AOFAS) score as well as subjective satisfaction. Results: Flexor tenotomy (19 cases) was the most common combined surgery. Floating toe (4 cases) was the most common complication. The last follow-up alignment of phalanges was better than good in 71 toes (77.2%) in anteroposterior view and in 69 toes (75.0%) in lateral view. Sixty one cases (85.9%) resulted in better satisfaction than 'good' and the final average AOFAS score was 87.4. Conclusion: Resection arthroplasty is a valuable surgical option for treatment of lesser toe deformity, with high patient satisfaction, easy surgical technique and remarkable correction of deformity.

• Journal of Korean Foot and Ankle Society
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• v.25 no.4
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• pp.165-170
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• 2021

Purpose: This study sought to evaluate the clinical effectiveness of the shortening effect of the modified Weil osteotomy for the treatment of Freiberg's disease. Materials and Methods: We reviewed 21 cases treated with the modified Weil osteotomy for Freiberg's disease from November 2005 to June 2019. The average follow-up period was 32.5 months and the mean age of the patients was 38.3 years. The clinical results were analyzed using the American Orthopaedic Foot and Ankle Society (AOFAS) lesser metatarsophalangeal-interphalangeal scale, the visual analogue scale (VAS), and the range of motion (ROM) of the metatarsophalangeal joint. In the radiologic evaluation, the length of preoperative and postoperative metatarsal shortening was compared. Results: The average AOFAS lesser metatarsophalangeal-interphalangeal scale showed an improvement from 60.5 preoperatively to 90.9 at the latest follow-up. VAS showed a decrease from 5.4 preoperatively to 0.9 at the latest follow-up. ROM of the affected metatarsophalangeal joint increased from 40.2 degrees preoperatively to 58.6 degrees at the latest follow-up. The mean length of metatarsal shortening was 6.7 mm. There was no transfer metatarsalgia, osteonecrosis, and definite joint space narrowing. Conclusion: Modified Weil osteotomy with second layer cutting is an effective treatment option to restore the joint surface and painless joint motion for patients with Freiberg's disease.

• Journal of Korean Foot and Ankle Society
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• v.28 no.1
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• pp.8-14
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• 2024

Purpose: Ankle fracture fixation is the gold standard of treatment but it does have its own complications. There is inadequate data regarding the comparative effectiveness of early vs. delayed fixation for open ankle fracture outcomes. This study compares the clinical and functional outcomes of open ankle fractures treated by early or delayed definitive fixation and identifies the limitations of both methods. Materials and Methods: All 73 patients enrolled in the study underwent surgical intervention within 24 hours of injury. The early fixation group (group A) consisting of 39 patients underwent definitive fixation as an index procedure, while the delayed fixation group (group B) consisted of 34 patients who underwent debridement and external fixator application as an index procedure and definitive fixation when soft tissue condition was conducive. All patients were evaluated at 2, 6, and 12 weeks postoperatively and then three monthly for a year. Results: Enneking and American Orthopaedic Foot and Ankle Society scores were markedly higher in the early fixation group at 6 months postoperatively (p-values <0.001 and 0.011, respectively). However, no discernible intergroup difference was evident at 12 months postoperatively. Between 6 and 12 months, group functional outcome scores were significantly different. At 6 months, there was a substantial difference in dorsiflexion between the two groups (p-values 0.001 and <0.001, respectively), but no difference was observed at 12 months postoperatively. At 6 and 12 months, group average plantar flexions were non-significantly different. Conclusion: Early definitive fixation of complex ankle fractures using a targeted approach produced promising results for lower grade open fractures (grades 1 and 2), and delayed definitive fixation, after initial external fixation to allow for soft tissue stabilization, produced promising results for higher grade open fractures (grades 3A and 3B). At 12-month follow-ups, clinical and functional outcomes achieved using these strategies were equivalent.

• PNF and Movement
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• v.22 no.2
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• pp.243-255
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• 2024

Purpose: Although foot muscle imbalance has been confirmed in patients with hallux valgus deformity, there is insufficient information on how corrective taping affects muscle activity and contraction rate of the foot muscles. The purpose of this study was to confirm the effectiveness of Mulligan taping as a treatment method for hallux valgus deformity by examining changes in muscle activity and contraction rate when Mulligan taping with inelastic tape was applied to these patients. Methods: Thirty-two patients with hallux valgus deformity were randomly divided into two groups, experimental and control. In the experimental group, Mulligan taping with inelastic tape was applied to correct the hallux valgus angle of the big toe, and in the control group, placebo taping was performed in which inelastic tape was applied in a straight line without modifying the angle of the big toe. Muscle activity and muscle contraction rate were measured before and after the intervention, and changes were compared and analyzed. Results: In the experimental group where Mulligan taping was applied, the muscle activity and muscle contraction rate of the abductor hallucis muscle significantly increased after the intervention (P < 0.05). On the other hand, the muscle activity and muscle contraction rate of the adductor hallucis muscle and tibialis posterior muscle significantly decreased (P < 0.05). There was no significant difference in muscle activity and muscle contraction rate in the control group, where placebo taping was applied (P > 0.05). Conclusion: Mulligan taping significantly changed muscle activity and contraction rates compared to placebo taping. By correcting the position of the big toe, the activity and contraction rate of the abductor hallucis muscle increased, while the activity and contraction rate of the adductor hallucis muscle and tibialis posterior muscle decreased. Therefore, Mulligan taping is considered an intervention that can prevent symptom worsening and enhance foot function by improving muscle imbalance in patients with hallux valgus deformity.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.8 no.1
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• pp.6-10
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• 2015

Purpose: To evaluate the effectiveness of extracorporeal shock wave therapy (ESWT) for postoperative pain after surgery around ankle. Materials and Methods: We included 21 patients who performed an operation around ankle from 2009 to 2013. 4 times ESWT were applied to the patients who have tenderness more than visual analog scale (VAS) point 4. We evaluated the VAS at each sessions and final follow-up, and American Orthopedic Foot and Ankle Society ankle-hindfoot score (AFOAS) was checked at preoperative and final follow-up. Patient's satisfaction and complications were surveyed. Results: Preoperative VAS was mean 4.7, postoperative pain VAS was mean 6.0 at 4.5 months follow-up. The VAS after ESWT each session at 1, 2, 3 weeks and final follow-up were 4.8, 3.2, 2.3, 2.9, respectively. Mean final follow-up period was 9.4 months. Final VAS were significantly decreased (p<0.001). Final VAS were increased from VAS at last session of ESWT, however, not significant (p=0.189). AOFAS significantly improved from preoperative 60 to final follow-up 86 (p<0.001). Excellent was 12 patients (57%), good was 4 patients (19%), no change was 3 patients (14%) and poor was 2 patients (9%). 1 patient complained a dizziness and nausea during ESWT. Conclusion: ESWT for postoperative pain after ankle surgery shows satisfactory pain reduction in 76% of all patients without severe complication.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.1
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• pp.47-57
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• 2016

In this paper, we measured human body signals in order to verify a active harness system that we developed for gait and balance training. The experimental procedure was validated by tests with 20 healthy male subjects. They conducted motions of Activities of Daily Living(ADL)(Normal Walking, Stand-to-Sit, Sit-to-Stand, Stair Walking Up, and Stair Walking Down) according to body weight support rates (0%, 30%, 50% of subjects' body weight). The effectiveness of the active harness system is verified by using the results of foot pressure distribution. In normal walking, the decrease of fore-foot pressure, lateral soleus muscle and biceps femoris muscle were remarkable. The result of stand-to-sit results motion indicated that the rear-foot pressure and tibialis anterior muscle activities exceptionally decreased according to body weight support. The stair walking down show the marked drop of fore-foot pressure and rectus femoris muscle activities. The sit-to-stand and stair walking up activities were inadequate about the effect of body weight support because the velocity of body weight support system was slower than male's activity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1161-1167
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• 2016

In this study, an attempt was made to conduct a case study on the development of ground expansive displacement due to lack of bearing capacity of original ground in spite of applying reinforcement treatments that intended to enhance the stability of big size high-speed rail tunnel in large fault zone. For the purpose of this, in-situ measurements made in the middle of excavation stage were analyzed in order to characterize ground responses and numerical analysis was performed to evaluate the effectiveness of reinforcement technique such as elephant foot method applied for this site via comparing with field monitoring measurements. In addition, further numerical studies were carried out to investigate the influence of leg pile installation angle and length, which is one of types of elephant foot method. The results revealed that the optimum condition for the leg pile installation is to maintain 45 degree of installation angle along with 6 meter of embedment depth.