• Korean Journal of Applied Biomechanics
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• v.14 no.2
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• pp.85-103
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• 2004

This study was conducted to determine what effects would the midsole hardness of running shoes have on shoe flex angle and maximum propulsive force. Furthermore, the relationship between the shoes flex angle and maximum propulsive force was elucidated in order to provide basic data for developing running shoes to improve sports performances and prevent injuries. The subjects employed in the study were 10 college students majoring in physical education who did not have lower limbs injuries for the last one year and whose running pattern was rearfoot strike pattern of normal foot. The shoes used in this study had 3different hardness, shore A 40(soft), 50(medium) and 60(hard). The subjects were asked to run at a speed of $4{\pm}0.08m/sec$, and their movements were videotaped with 2 S-VHS video-cameras and measured with a force platform. And the following results were obtained after analyzing and comparing the variables. 1. Although the minimum angle of shoes flex angle was estimated to appear at SFA4, it appeared at SFA2 except in those shoes with the hardness of 40. 2. The minimum angle of shoes flex angle was $145.1^{\circ}$ with barefoot. Among the shoes with different hardness, it was the smallest when the hardness was 50 at $149.9^{\circ}$. The time to the minimum angle was 70.7% of the total ground contact time. 3. Maximum propulsive force according to midsole hardness was the largest when the hardness was 50 at $1913.9{\pm}184.3N$. There was a low correlation between maximum propulsive force and shoes flex angle.

• Journal of Korean Foot and Ankle Society
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• v.12 no.1
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• pp.20-25
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• 2008

Purpose: The purpose of this study is comparison of radiological and clinical outcomes between proximal metatarsal osteotomy and distal chevron osteotomy for the correction of hallux valgus. Materials and Methods: In this retrospective study, we included subjects who underwent the correction of hallux valgus in our institution between March 2001 and August 2006, with a minimum follow-up of 12 months. The group of proximal metatarsal osteotomy was 23 patients (34 feet); the group of distal chevron osteotomy was 20 patients (26 feet). The group of proximal metatarsal osteotomy was composed of 26 severe cases (76.5%) and 8 moderate cases (23.5%); the group of distal chevron osteotomy was composed of 13 severe cases (50.0%) and 13 moderate cases (50.0%). Results: Compared to preoperative values, the hallux valgus angle, the first-second intermetatarsal angle and the distance of first-fifth metatarsal head were significantly decreased in two groups (p<0.05). In each parameter, the hallux valgus angle was decreased 66.3% (proximal metatarsal osteotomy) versus 49.6% (distal chevron osteotomy), which were significant (p=0.037). The first-second intermetatarsal angle and the distance of first-fifth metatarsal head were not significant. Mayo clinic forefoot scoring system (FFSS) score was significantly improved in two groups (p<0.05). The ratio of improvement was not significant (p=0.762). In severe group, hallux valgus angle and the first-second intermetatarsal angle was significantly decreased in proximal metatarsal osteotomy group compared to distal chevron osteotomy group (p<0.05), but the difference of the distance of first-fifth metatarsal head and FFSS score was not significant in both groups. In moderate group, the difference of all parameters was not significant in both groups. Conclusion: Although both proximal metatarsal osteotomy and distal chevron osteotomy showed satisfactory result in FFSS, proximal metatarsal osteotomy was more proper operative technique than distal chevron osteotomy in severe group, because of superiority of correction in radiological parameters.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.241-250
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• 2022

Purpose : The purpose of this study was to investigate the effect of backward walking exercise on changes in the cervical angle and gait parameters in subjects with moderate forward head posture. Methods : Four subjects were selected for this study. In particular, subjects with an average of 43 subjects with moderate craniovertebral angles were selected as the criteria for subject selection. The exercise program consisted of a 5 minutes warm-up exercise, 20 minutes main exercise, and 5 minutes cool-down exercise. In the main exercise, the treadmill speed was 2.5 km/h for men, 2.0 km/h for women in the first week, from the 2nd week to the 4th week, it was increased by 0.5 km/h every week. Results : Craniovertebral angle increased by 2.06±2.46 ° before and after the backward walking exercise, and craniorotational angle decreased by -1.69±3.33 ° before and after exercise. As for the gait parameters, in the amount of change before and after the backward walking exercise, the left foot pressure was 4.58±5.70 % from front to back and the right foot pressure was 5.08±3.06 % from front to back. The left step length and right step length showed a change of -.33±4.43 cm and -2.08±7.26 cm, respectively. stride length showed a change of -2.59±11.18 cm. The left and right stance phase showed a change of -1.02±2.03 % and -1.23±1.54 %, respectively. The left and right swing phase showed changes of 1.02±2.03 % and 1.22±1.53 %, respectively. The left and right step times were -.01±.06 sec and -.02±.12 sec, respectively. The stride time showed a change of -.03±.18 sec. Conclusion : Changes in cervical angle and gait parameters were confirmed by performing backward walking exercise for subjects with moderate forward head posture for 4 weeks. Therefore, additional research should be conducted based on this case study.

• Journal of Korean Foot and Ankle Society
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• v.11 no.1
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• pp.23-27
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• 2007

Purpose: Scarf osteotomy can provide the simultaneous correction of the hallux valgus angle (HVA), 1-2 intermetatarsal angle ($IMA_{1-2}$), DMAA and the plantar displacement of the fragment. The study was conducted to understand the multi-dimensional correction of the hallux valgus. Materials and Methods: Fourty eight patients who had undergone Scarf osteotomy with hallux valgus at more than $30^{\circ}$ of HVA and more than $15^{\circ}$ of $IMA_{1-2}$ were studied. Before an osteotomy, a reference K-wire was inserted to the 1st metatarsal head. After the osteotomy, the plantar fragment was moved laterally and the proximal end of the fragment was forced beyond the distal end which resulted in an internal rotation of the head fragment to correct the DMAA. Results: The HVA improved an average of $33.3^{\circ}$ to $7.7^{\circ}$ with the IMA1-2 respectively from $15.4^{\circ}$ to $6.5^{\circ}$. The DMAA improved an average of $19.5^{\circ}$ ($5.2-30.9^{\circ}$) to $4.5^{\circ}$ ($0.4-13.8^{\circ}$). By checking the angle, which was at an average of $25^{\circ}$ between the plantar surface of the foot and the osteotomy plane, the average distance of 1.9 mm (1.18-3.1 mm) of plantar displacement was measured using the value of sine (sin 25 = 0.422). Conclusions: It is possible to correct the HVA, IMA1-2 and DMAA simultaneously with one osteotomy making the lateral shift, the internal rotation and the plantar displacement of the plantar head fragment as desired. Despite the technicality and difficulty of the Scarf osteotomy, once familiarized through myriad procedures, all disadvantages are outweighed by the success and satisfaction of both patient and surgeon.

• Journal of Korean Foot and Ankle Society
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• v.13 no.2
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• pp.113-117
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• 2009

Purpose: To evaluate the short-term results of medial displacement calcaneal osteotomy without flexor digitorum longus transfer for flexible flatfoot deformity. Materials and Methods: Twenty four patients (25 feet) who had undergone medial displacement calcaneal osteotomy without flexor digitorum longus transfer for flexible flatfoot between July 2004 and May 2007 were included. The mean age was 43.6 years (16~78 years). The mean follow-up was 26 months (14~50 months). Clinical outcomes were assessed using American Orthopaedic Foot and Ankle Society (AOFAS) score and visual analogue scale (VAS). Six radiographic parameters were measured from weightbearing radiographs to assess the difference between preoperative and postoperative radiographs. Results: The mean AOFAS score improved from 57.9 points preoperatively to 89.2 points at latest follow-up (p=0.000). The mean VAS improved from 62 points preoperatively to 23 points at latest follow-up (p=0.000). The mean talonavicular coverage angle on anteroposterior (AP) view changed from 20.2 degrees to 16.0 degrees (p=0.002). The mean calcaneal pitch angle on lateral view changed from 12.6 degrees preoperatively to 14.5 degrees at latest follow-up (p=0.001). Regarding these radiographic parameters, the difference between interobserver measurements was larger than that between pre- and post-operative measurements. The calcaneus was transferred medially by average 11.8 mm (p=0.003), which was 27.9% of the width of calcaneal tuberosity (p=0.000). The mean talo-first metatarsal angle on AP and lateral views, and navicular height on lateral view were not significantly changed. Conclusion: Medial displacement calcaneal osteotomy without flexor digitorum longus transfer for flexible flatfoot could lead to improve the clinical outcomes, although the restoration of medial longitudinal arch was not clinically significant.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.979-986
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• 2019

The purpose of this study devised a method for the examination of the images of the first and second rib fractures of the axillary using Rib Rando Phantom. The position of the phantom and the angle of the X-ray tube were changed to vertical, head 5° and foot 5°. The Radiological Technologists subjectively evaluated the acquired images and the evaluation data were analyzed by SPSS 3.0 ver. The signal to noise ratio(SNR) was calculated using the ImageJ Program. As a result, the cronbach alpha value was significantly higher at 0.789. The SNR was highest at 6.038 when the X-ray tube was tilted 5° toward the head in the front of the ribs and highest at 7.860 when the X-ray tube was tilted 5° toward the foot. Radiographic Techniques proposed axillary ribs this study are as follows. The anterior rib scan is examined by elevating the fractured area and changing the X-ray tube angle by 5° towards the head. The posterior ribs scan is examined by attaching the fractured area and changing to the X-ray tube angle by 5° towards the foot. It is considered that such an inspection method can obtain a sharp image.

• Journal of Korean Foot and Ankle Society
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• v.23 no.4
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• pp.166-172
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• 2019

Purpose: This study evaluated the clinical and radiological results after reinforcement of the weakened medial joint capsule using Internal Brace (Arthrex) for treating severe hallux valgus. Materials and Methods: This study reviewed 56 cases of 50 patients that were followed-up postoperatively for at least 12 months, from September 2017 until August 2018. An extended distal chevron osteotomy combined with a distal soft-tissue release was performed by a single surgeon to treat severe hallux valgus. Internal Brace was applied in 12 cases (group A) who had weakened medial joint capsules, and capsulorrhaphy was performed in 44 cases (group B), and these two groups were compared postoperatively for the clinical and radiological results. The postoperative complications were also investigated. Results: No significant differences at 1-year follow-up on the Manchester-Oxford Foot Questionnaire and the patients' satisfaction scores were found between the two groups (p=0.905 and p=0.668, respectively). For the radiology, the changes of the values between before surgery and at 1-year follow-up according to the group showed no significant differences in the hallux valgus angle, intermetatarsal angle, and the hallux interphalangeal angle (p=0.986, p=0.516, p=0.754, respectively). Recurrence of hallux valgus was reported in two cases in group A, and in three cases in group B. Transfer metatarsalgia occurred in 4 cases in group B. Conclusion: Based on these results, we recommend the capsule reinforcing technique using Internal Brace as a successful operative option for treating a weakened medial capsule in patients with severe hallux valgus.

• Journal of Korean Foot and Ankle Society
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• v.23 no.4
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• pp.159-165
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• 2019

Purpose: This study investigated the recurrence rate after performing hallux valgus correction using scarf and Akin osteotomy, and also identified the correlation and cut-off values of both the preoperative and postoperative radiographic parameters as risk factors for the recurrence of hallux valgus. Materials and Methods: We reviewed 87 hallux valgus patients (122 feet) who received scarf and Akin osteotomy from January 2007 to August 2015. The clinical outcomes were evaluated using the visual analogue scale (VAS) and American Orthopaedic Foot and Ankle Society (AOFAS) scores. The radiological outcome measures included the hallux valgus angle (HVA), intermetatarsal angle (IMA), and distal metatarsal articular angle (DMAA) as determined on the serial weight bearing radiographs. Recurrence was defined as more than 20 degrees of HVA noted on the final follow-up radiograph. Those radiological factors associated with recurrence were evaluated and analyzed. Results: The mean follow-up duration was 20.6 months (12.0~46.5 months) and the mean age was 44 years (13~80 years). The VAS and AOFAS scores were significantly improved at the time of the final follow-up (7.0 to 2.0, p<0.001; 78.0 to 92.0, p<0.001; respectively). Significant corrections in the HVA, IMA, and DMAA were obtained (p<0.001). Eleven (9.0%: 11/122) cases experienced recurrent hallux valgus deformity. The postoperative IMA, DMAA and HVA showed significant moderate to strong correlation with HVA at the final follow-up (Pearson correlation coefficient: 0.44, 0.70, and 0.88, respectively; p<0.001). Postoperative HVA>16.7 degrees, postoperative DMAA>13.9 degrees, and postoperative IMA>8.2 degrees showed statistically significant correlation with radiological recurrence at the last follow-up, and the odds ratio of each variable was high in order. Conclusion: Our radiographic results indicated that postoperative HVA>16.7 degrees, postoperative DMAA>13.9 degrees, and postoperative IMA>8.2 degrees can be risk factors for hallux valgus recurrence. These risk factors may be helpful for modifying surgical procedures and preventing the recurrence of hallux valgus.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.6
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• pp.538-546
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• 2015

This paper describes an intelligent ankle assistive robot which provides assistive power to reduce ankle torque based on an analysis of ankle motion and muscle patterns during walking on level and sloped floors. The developed robot can assist ankle muscle power by driving an electric geared motor at the exact timing through the use of an accelerometer that detects gait phase and period, and a potentiometer to measure floor slope angle. A simple muscle assistive link mechanism is proposed to convert the motor torque into the foot assistive force. In particular, this mechanism doesn't restrain the wearer's ankle joint; hence, there is no danger of injury if the motor malfunctions. During walking, the link mechanism pushes down the top of the foot to assist the ankle torque, and it can also lift the foot by inversely driving the linkage, so this robot is useful for foot drop patients. The developed robot and control algorithm are experimentally verified through walking experiments and EMG (Electromyography) measurements.

• Journal of Korean Foot and Ankle Society
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• v.13 no.2
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• pp.142-145
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• 2009

Purpose: The aim of this study was to retrospectively evaluate the clinical and radiological results of the first metatarsophalangeal joint arthrodesis with two crossed screws fixation. Materials and Methods: We treated 23 patients (24 cases) with arthrodesis of the first metatarsophalangeal joint using two crossed screws fixation between December 2000 and May 2005. There were 3 male patients and 20 female patients. Ages ranged from 28 to 74 years (mean, 50 years). Follow-up ranged from 4.1 to 8.2 years (mean, 6.5 years). The American Orthopaedic Foot and Ankle Society (AOFAS) score and their satisfaction was evaluated clinically, foot anteroposterior and lateral radiograph, radiologically. Results: Of the 24 cases, 6 had surgery for dorsal plate and screws fixation because of failure to acquire firm fixation with two crossed screws fixation. All 6 cases acquired bony union. Fusion of the hallux first metatarsophalangeal joint occurred in 16/18 cases (89%). Nonunion occurred in 2 cases (11%) and was asymptomatic. At last follow-up, hallux valgus angle ranged from 11 to 25 degrees(mean, 17.7 degrees), dorsiflexion ranged from 15 to 25 degrees (mean, 22 degrees).The mean preoperative AOFAS score of 37 points(range, 28 to 45 points) improved to a mean of 77 points (range, 65~90 points) postoperatively. The result of the procedure as rated subjectively by the patient was excellent for 5 cases, good for 11 cases and fair for 2. Conclusion: Comparatively, the arthrodesis of the first metatarsophalangeal joint with crossed screws fixation showed a satisfactory clinical results, we thought that require technical attention for firm fixation in operation.