• Journal of Korean Foot and Ankle Society
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• v.17 no.2
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• pp.100-105
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• 2013

Purpose: To present radiographic characteristics and report the clinical results of the operative treatment of M$\ddot{u}$ller-Weiss disease. Materials and Methods: This is a retrospective study including 13 patients, 14 feet who had been operated for M$\ddot{u}$ller-Weiss disease between April 2006 and December 2011. Osteoarthritis of the peri-navicular joints were radiographically evaluated. Various range of peri-navicular fusion and joint-preserving surgeries according to patients' symptoms and radiographic findings were done. The clinical results were evaluated by American Orthopaedics Foot and Ankle Society (AOFAS) midfoot scale and visual analogue scale (VAS). Results: On radiographs, osteoarthritic changes were presented at talonavicular joint in 11 cases, calcaneocuboid joint in 7 cases, subtalar joint in 6 cases, naviculo-cuneiform joint in 1 case. The mean anteroposterior talocalcaneal angle was 16.6 degrees. On hindfoot alignment view, 6 cases were varus, 5 cases were neutral and 3 cases were valgus alignment. Fusion comprised 6 cases in triple fusion, 1 case in talonavicular-cuneiform fusion, 2 cases in talonavicualr fusion and 1 case in talonavicular & calcaneocuboid fusion. Joint-preserving surgeries were bony fragment excision of the lateral part of navicular & medial displacement calcaneal osteotomy in 1 case, bony spur excision of talonavicular joint in 1 case and medial displacement calcaneal osteotomy in 2 cases. The postoperative AOFAS and VAS score were improved significantly (p=0.000, p=0.000). Conclusion: In cases of M$\ddot{u}$ller-Weiss disease without osteoarthritic changes at peri-navicular joints, fragment excision of navicular, bony spur excision with or without medial displacement calcaneal osteotomy were effective operative treatments.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.249-256
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• 2015

Objective : The purposes of this study was to perform a kinematical analysis on age and walkway types in elderly women subjects. Method : Forty subjects participated in the experiment (A1 group - age: $67.30{\pm}1.49yrs$, height: $153.81{\pm}4.47cm$, weight: $61.80{\pm}5.24kg$, A2 group - age: $71.70{\pm}1.10yrs$, height: $152.01{\pm}2.84cm$, weight: $59.69{\pm}7.34kg$, A3 group - age: $76.80{\pm}0.98yrs$, height: $150.16{\pm}6.08cm$, weight: $57.27{\pm}6.42kg$, A4 group - age: $81.80{\pm}0.60yrs$, height: $152.18{\pm}4.77cm$, weight: $55.80{\pm}7.78kg$). The study method adopted was the 3D analysis with six cameras. Ground type were classifed as gait pattern on flat, ascent and descent ramp. For the statistical analysis, the SPSS 21.0 was used to perform Repeated measured Two-way ANOVA. Results : In velocity of CM, there was faster movement on flat ground. When it came to the velocity of right toe, there was no significance in early mid-swing of right foot, but A4 was the slowest in late mid-swing of right foot on flat ground. In joint angle in left foot strike, the left hip joint and knee joint were more flexed in descent ramp, In addition left and right ankle joints were more plantarflexed in descent ramp, and left ankle joint was more plantarflexed in the over 75 yrs age groups. Conclusion : The higher age group were more flexed in lower body joints during descent ramp.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.749-759
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• 2009

The purpose of this study was to provide basic information for improving a soft tennis forehand middle volley technique based on kinematic and kinetic analyses of volleys performed by four male national tennis players($33.3{\pm}2.16$ years). The results are as follows. The first phase of the stroke was the longest, covering 64.7% of the stroke time. The displacement of the center of gravity was 48.1% to the right and 54% to the front in the first phase. When impacted, the elbow joint showed the highest average velocity, 3.67m/s, and the upper arm segment displayed the highest angular velocity, $201^{\circ}/s$. The average of the elbow angle and the ball velocity were $149^{\circ}$ and 18.9m/s, respectively. In the ground reaction force, the left and right foot forces in both the x and y directions showed a statistically significant difference. This result seems to indicate that when the left foot is pushed to the right, the force of the right foot is proportional and symmetrical to the left, serving as a supporter.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.193-205
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• 2006

This study was to analysis the kinematic and kinetic differences between new walking shoe(NWS : RYN) and general walking shoe(GWS). The subjects for this study were 10 male adults who had the walking pattern of rearfoot shrike with normal foot. The movement of one lower leg was measured using plantar pressure and Vicon Motion Analysis Program(6 MX13 and 2 MX40 cameras : 100 f / s) while the subjects walked at the velocity(1.5m/s. on 2m).. The results of this study was as follows : 1. The NWS was better than the GWS that caused injuries such as adduction, abduction and pronation are reduced While walking on a perpendicular surface, the landing angle and the knees angles were extensive which makes walking more safe which reduces anxiety and uneasiness. 2. The bottom of the NWS were now made into a more circular arch which supports the weight of the body and reduces the irregular angles when wearing GWS. This arch made the supporting area more wide which made the upholding the trunk of the body more effective. The whole bottom of the foot that supports the weight is more flexible in addition, increases the safeness of walking patterns and the momentum of the body. 3. The moment the heel of the foot of the NWS touch the ground, the range of the pressure were partially notable and the range of the pressure on the upper part of the thigh were dispersed The injuries that occurred while walking. primary factors when a shock related injuries are reduced Judgements of the impacts of the knees and the spinal column dispersing could be made.

• Journal of Korean Foot and Ankle Society
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• v.16 no.3
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• pp.175-180
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• 2012

Purpose: To evaluate the radiological and clinical results after open reduction and internal fixation with calcaneal F plate and locking calcaneal plate using lateral extensile approach in the treatment of intra-articular calcaneal fracture Materials and Methods: This study included 34 cases of 33 patients followed up for at least 6 months postoperatively. F plate was applied in 18 cases (Group 1), locking plate was used in 16 cases (Group 2) and compared radiological and clinical results between two groups. Results: Radiollogically, the mean Bohler angle was improved from $5.5^{\circ}$ preoperatively to $20.1^{\circ}$ postoperatively and $18.8^{\circ}$ at the last follow up in group 1 and $8.6^{\circ}$ preoperatively, $21.4^{\circ}$ postoperatively and $20.3^{\circ}$ at last follow up in group 2. Bone union was observed in all cases and 4 cases of screw loosening were noted in Group 1 with extended fracture to anterior process. At the last follow up, both groups showed clinical results in American orthopedic foot and ankle society ankle hindfoot score, 76(77 in Sanders type II and 75 in type III) in group 1 and 72(73 in type II and 70 in type III) in group 2. Conclusion: F plate and locking plate showed firm fixation and satisfactory clinical results in the treatment of intra-articular calcaneal fracture. We suggest applying locking plate in cases with extended fracture to anterior process, considering screw loosenings in those who were treated with F plate fixation.

• Physical Therapy Korea
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• v.29 no.3
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• pp.208-214
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• 2022

Background: Pronated foot posture (PFP) contributes to excessive dynamic knee valgus (DKV). Although foot orthoses such as medial arch support (MAS) are widely and easily used in clinical practice and sports, few studies have investigated the effect of MAS on the improvement of DKV during stair descent in individuals with a PFP. Moreover, no studies reported the degree of improvement in DKV according to the severity of PFP when MAS was applied. Objects: This study aimed to examine the immediate effect of MAS on DKV during stair descent and determine the correlation between navicular drop distance and changes in DKV when MAS is applied. Methods: Twenty individuals with a PFP (15 males and five females) participated in this study. The navicular drop test was used to measure PFP severity. The frontal plane projection angle (FPPA) was calculated under two conditions, with and without MAS application, using 2-dimensional video analysis. Results: During stair descent, the FPPA with MAS (173.1° ± 4.7°) was significantly greater than that without MAS (164.8° ± 5.8°) (p < 0.05). There was also a significant correlation between the navicular drop distance and improvement in the FPPA when MAS was applied (r = 0.453, p = 0.045). Conclusion: MAS application can affect the decrease in DKV during stair descent. In addition, MAS application should be considered to improve the knee alignment for individuals with greater navicular drop distance.

• Journal of the Korea Fashion and Costume Design Association
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• v.11 no.2
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• pp.183-195
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• 2009

In this study, foot shapes were compared between the men in their 20's and 60's, with the application of 3-dimensional measurement data, and the classification was established in consideration of each of their features. The results are as follows: 1. The investigation into the differences between the groups for the 3-dimensional measurement items of the men in their 20's and 60's indicated that those in their 20's had larger values than those in the 60's age group for all of the length items, while those in the 60's age group had larger values for all of the angle items. 2. The analysis of the constituting factors for the feet of those in their 60's and 20's resulted in the 7 items for the 20's age group and 8 items for those in the 60's age group. 3. The comparison of foot classifications for the 60's age group and 20's age group presented 3 types each for both groups, but the features of each type was different. To examine each characteristic by each type and age group, following can be determined of the 60's age group. Type 1 had a thick instep, high malleolus position and heel and a thick formed ankle. Type 2 the entire foot was small, and the big toe was formed in such a way that it tened to bend toward the inside. When the whole size compared with similar Type 1, Type 3 had a low instep, a low heel, the big toe did not bend and ankle form was thin. The following can be determined of the 20's age group. Type 1 had narrow width a thin ankle and the big toe was formed in such a way that it bended toward the inside. Compared with length, Type 2 had wide width and a thick ankle. Type 3 had a larger overall size, thick instep and wide and the toe was big, but the characteristic of inside and outside of a malleolus position was low and the big toe's form showed no tendencies to bend.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.359-367
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• 2009

This study was conducted to provide useful information for the scientific training of spikes and instruction, by analyzing all kinematical variants including time, distance, velocity, angle factors in spike movements of volleyball matches. The subjects were 4 foreigner players, who participated in the V-League of 2008-2009. The conclusion from this study is as follows. Time for a jumping step was .33s, and Angelko had a bit longer takeoff time than other players. In Angelko and Anderson who were leading in attack power, the whole distance of a spike motion was relatively short, less than 4m. The moment when the center of gravity reached the lowest point was when the right foot bearing weight in the jumping step was passing the left foot, and the highest point of gravity was 2.30m, which appeared just before the impact. The horizontal speed of the center of the gravity was highest as 4.19m/s at the beginning of a jumping step, and lowest at the stance phase of the fore foot just before takeoff. The vertical speed of the center of the gravity was lowest after the right foot touched the ground, and highest after the takeoff of the fore foot. Impact was 3.22m, and the highest ball speed was 28.18m/s.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.59-66
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• 2018

The utilized coefficient of friction (UCOF) as a ratio of the shear force to the normal force on the ground during walking is used to identify the point at which slip is likely to occur. Shoe walking will change the utilized coefficient of friction by shoe design such as sole thickness and hardness, heel shape, and outsole pattern. In this study, subjects are 21 adults (10 female, 11 male, age: $25.2{\pm}2.3yrs$, height: $165.6{\pm}7.2cm$), analysis variables were walking speed, GRF, when the UCOF is maximal, and Tangent of CoP-CoM angle, and correlation analysis with the utilized friction coefficient (UCOF). As a result, First, for the shod walking the time point which UCOF is maximum about heel strike was faster and the magnitude was larger than for barefoot walking. Second, the correlation between the tangent of CoP-CoM and UCOF of right foot was higher at the left heel striking point (UCOF2_h) which occurred in the post propulsion phase than at the right heel striking point (UCOF1_h). This suggests that the right foot UCOF is related to the braking phase of left foot( which is the propulsion phase of right foot) rather than the braking phase of right foot.

• Journal of Korean Foot and Ankle Society
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• v.21 no.3
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• pp.88-92
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• 2017

Purpose: The objective of this study was to confirm the results of the modified Lapidus procedure on moderate to severe hallux valgus patients with first tarso-metatarsal joint hypermobility. Materials and Methods: A retrospective study was conducted on 42 cases of 35 patients who underwent the modified Lapidus procedure between March 2006 and December 2014. A comparative analysis was performed on the preoperative and postoperative subjective satisfaction of patients and radiologic index. Moreover, the correlation between the follow-up time and patient's operative satisfaction, as well as between the proficiency of the operator and patient's operative satisfaction was analyzed. Complications were also evaluated. Results: Out of the total of 35 patients, 3 were male and 32 were female. The mean age was 61.3 years (range, 34~79 years), and the mean follow-up time was 22.1 months (range, 6~90 months). The overall satisfaction level was 67.6% and the mean hallux valgus angle improved from preoperative $40.5^{\circ}$ to postoperative $12.2^{\circ}$ (p<0.001). The mean 1, 2 intermetatarsal angle improved from preoperative mean of $16.9^{\circ}$ to postoperative mean of $7.6^{\circ}$ (p<0.001), and the sesamoid position improved significantly, from preoperative 2.7 to postoperative 0.9 (p<0.001). Furthermore, there was no correlation between the follow-up time and the American Orthopaedic Foot and Ankle Society (AOFAS) hallux scale; also no correlation between the year the operation took place and the AOFAS hallux scale. In terms of complications, we observed screw irritation in 6 cases, hallux varus in 2 cases, and recurrence of hallux valgus and nonunion in one case. Conclusion: Contrary to our concerns, the level of complications was not high; however, the satisfaction level of patients was also not very high. Therefore, careful selecting of patients and sufficient consultation time is needed before surgery. In addition, since the causes of postoperative dissatisfaction still remain unclear, further studies are necessary.