• Journal of the Korean Society for Precision Engineering
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• v.29 no.2
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• pp.239-244
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• 2012

The prevalence of knee osteoarthritis was higher people with lower limb amputation. This was identified that transfemoral amputees have a greater external knee adduction moment than ablebodied subjects by biomechanical studies. Therefore, they need rehabilitative intervention for prevention and reduction of knee osteoarthritis. The purpose of this study was to determine the effect of lateral wedge insole used in the treatment of knee osteoarthritis. This study was participated in fourteen unilateral transfemoral amputees and we were analyzed the difference gait variables between without lateral wedge insole and with $5^{\circ}$ and $10^{\circ}$ lateral wedge insole during gait. Our results showed that step length ratio was more symmetrical and, hip adduction and ankle inversion angle were more close to normal value, and knee adduction moment was decreased as the wedge angle increases. We proposed that these data would be utilized conservative treatment of knee osteoarthritis in lower limb amputees.

• Advances in biomechanics and applications
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• v.1 no.4
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• pp.269-277
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• 2014

In skin-marker based motion analysis, knee translation measurement is highly dependent on a pre-selected reference point (functional center) on each segment determined by the location of anatomical landmarks. However, the placement of skin markers on palpable anatomical landmarks (i.e., femoral epicondyles) has limited reproducibility. Thus, it produces large variances in knee translation measurement among different subjects, as well as across studies. In order improve the repeatability of knee translation measurement, in this study an optimization method was introduced, by which the femoral functional center was numerically determined. At that point the knee anteroposterior translation during the stance phase of walking was minimized. This new method was tested on 30 healthy subjects during walking in gait lab with motion capture system. Using this new method, the impact of skin marker position (at anatomical landmarks) on the knee translation measurement has been minimized. In addition, the ranges of anteroposterior knee translations during stance phase were significantly (p<0.001) smaller than those measured by conventional method which relies on a pre-selected functional center ($11.1{\pm}3.5mm$ vs. $19.9{\pm}5.5mm$). The results of anteroposterior translation using this new method were very close to a previously reported knee translation (12.4 mm) from dual fluoroscopic imaging technique. Moreover, this new method increased the reproducibility of knee translation measurement by 50%.

• Journal of Korean Medicine Rehabilitation
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• v.28 no.2
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• pp.105-111
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• 2018

Objectives The purpose of this study was to examine the effects muscle fatigue at the knee muscles on balance during standing in healthy adults. Methods Thirty healthy adults were recruited along with their written informed consent. Subjects were randomly assigned to knee extensor group (fatigue on knee extensor, KE), and knee flexor group (fatigue on knee flexor, KF). And subjects performed exercise with each muscle group until muscle fatigue was induced. They were assessed balance ability by functional reaching test (FRT), limit of stability (LOS), and postural sway (one leg standing, normal eye open (NO), normal eye close (NC), pillow with eye open (FO), and pillow with eye close (FC)) before and after fatigue. Results There were significant group differences balance performances in FRT, anterior of limit of stability, one leg standing, and the muscle fatigue of knee muscles were decreased balance performances. The balance performance was affected by visual sense and proprioception. Conclusions These results show that the muscle fatigue of knee muscles decreased balance performance. Therefore, balance exercise program should be trained without muscle fatigue.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1664-1671
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• 2004

It is necessary to have a model that describes the feature of the knee Joint with a sufficient accuracy. Koreans, however, do not have their own knee joint model to be used in the total knee replacement arthroplasty. They have to use European or American models which do not match Koreans. Three-dimensional visualization techniques are found to be useful in a wide range of medical applications. Three-dimensional imaging studies such as CT(computed tomography) and MRI(magnetic resonance image) provide the primary source of patient-specific data. Three-dimensional knee joint models were constructed by image processing of the CT data of 10 subjects. Using the constructed model, the dimensions of Korean knee joint were measured. And this study proposed a three-dimensional model and data, which can be helpful to develop Korean knee implants and to analyze knee joint movements.

• Knee surgery & related research
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• v.30 no.4
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• pp.319-325
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• 2018

Purpose: Body mass index (BMI) is often used to predict surgical difficulty in patients receiving total knee arthroplasty (TKA); however, BMI neglects variation in the central versus peripheral distribution of adipose tissue. We sought to examine whether anthropometric factors, rather than BMI alone, may serve as a more effective indication of surgical difficulty in TKA. Materials and Methods: We prospectively enrolled 67 patients undergoing primary TKA. Correlation coefficients were used to evaluate the associations of tourniquet time, a surrogate of surgical difficulty, with BMI, pre- and intraoperative anthropometric measurements, and radiographic knee alignment. Similarly, Knee Injury and Osteoarthritis Outcome Score (KOOS) was compared to BMI. Results: Tourniquet time was significantly associated with preoperative inferior knee circumference (p=0.025) and ankle circumference (p=0.003) as well as the intraoperative depth of incision at the quadriceps (p=0.014). BMI was not significantly associated with tourniquet time or any of the radiographic parameters or KOOS scores. Conclusions: Inferior knee circumference, ankle circumference, and depth of incision at the quadriceps (measures of peripheral obesity) are likely better predictors of surgical difficulty than BMI. Further study of alternative surgical indicators should investigate patients that may be deterred from TKA for high BMI, despite relatively low peripheral obesity.

• Physical Therapy Rehabilitation Science
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• v.11 no.1
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• pp.1-7
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• 2022

Objective: The purpose of this study was to assess the validity of the global rating of knee function as a measure of participation restrictions experienced during activities of daily living and sports by patients with a history of anterior cruciate ligament reconstruction (ACLR). Design: Cross-sectional study. Methods: Forty-three subjects (33 males, 10 females, age=20.3 ± 1.3 years), at a mean of 31.2 ± 14.4 months following ACLR, participated in this study. During testing, subjects were first asked to provide a global rating of function by assessing their level of knee function on a 0 to 100 scale, with 0 points representing complete loss of function due to their knee injury and 100 points representing their level of function prior to their knee injury. After providing a global rating of function, subjects completed the Knee Outcome Survey (KOS) Activities of Daily Living Scale (ADLS) and Sports Activity Scale (SAS), which served as the measure of participation restrictions in this study. Results: Pearson product correlations revealed moderate relationships between the global rating of function and the ADLS (r=0.66, p<0.0001) and SAS (r=0.69, p<0.0001). Conclusions: The global rating of knee function provides a valid measure of participation restrictions experienced during activities of daily living and sports by patients with a history of ACLR.

• Journal of Digital Convergence
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• v.16 no.6
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• pp.213-222
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• 2018

This study purposed to verify the effects of knee balance taping therapy on knee pain and knee range of motion in the elderly with knee pain. The Quasi-experimental design, nonequivalent control group pretest-posttest was used in this study. Data collected from December 5 to 10, 2014. The participants were older than 60 with knee pain visiting senior community centers. Non-medicated elastic tapes were applied around the knee in the experimental group(n=21) and were not applied in the control group(n=19). Knee pain and range of motion were measured 3 times (before, after 1 hour, after 24 hours). Data were analyzed using ${\chi}^2$ test, Fisher's exact test, Mann-Whitney test, t-test, Repeated measure ANOVA with the SPSS version 21.0 program. The experimental group showed significantly decreased knee pain (F=34.03, p<.001) and increase in knee range of motion (F=7.83, p=.006). The results of this study confirm that knee balance taping therapy is an effective intervention for reducing pain and improving range of motion in elderly with knee pain.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.275-281
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• 2015

Objective : In order for Taekwondo athletes to perform destructive kicking performance, they are expected to have Taekwondo-specific muscle properties such as high muscle strength and power. The purpose of this study was to investigate the joint angle-dependent force-producing property of Taekwondo athletes' knee extensor muscles, which is one of the primary muscle groups involved in kicking performance. Method : Ten Taekwondo male athletes (age: $19.9{\pm}0.7yrs$, height: $180.6{\pm}6.2cm$, body mass: $75.9{\pm}8.9kg$, career: $9.2{\pm}2.9yrs$.) and 10 healthy male non-athletes (age: $26.3{\pm}2.6yrs$, height: $174.2{\pm}4.8cm$, body mass: $72.8{\pm}7.7kg$) participated in this study. Subjects performed maximum isometric knee extension at knee joint angles of $40^{\circ}$, $60^{\circ}$, $80^{\circ}$, and $100^{\circ}$ (the full knee extension was set to $0^{\circ}$) with the hip joint angles of $0^{\circ}$ and $80^{\circ}$ (the full extension was set to $0^{\circ}$). During the contractions, knee extension torque using an isokinetic dynamometer simultaneously with muscle activities of the rectus femoris (RF), and the vastus lateralis (VL) and vastus medialis (VM) using surface electromyography were recorded. Based on the torque values at systematically different knee-hip joint angles, the joint torque-angle relationships were established and then the optimal joint angle for the knee extensor was estimated. Results : The results of this study showed that the isometric knee extension torque values were greater for the Taekwondo athletes compared with the non-athlete group at all hip-knee joint angle combinations (p<.05). When the hip joint was set at $80^{\circ}$, the peak isometric torque was greater for the Taekwondo athletes compared with the non-athlete group ($313.61{\pm}36.79Nm$ and $221.43{\pm}35.92Nm$, respectively; p<.05) but the estimated optimum knee joint angles were similar ($62.33{\pm}5.71^{\circ}$ and $62.30{\pm}4.67^{\circ}$ for the Taekwondo athletes and non-athlete group, respectively). When the hip joint was set at $0^{\circ}$, the peak isometric torque was greater for the Taekwondo athletes compared with the non-athlete group ($296.29{\pm}45.13Nm$ and $199.58{\pm}25.23Nm$, respectively; p<.05) and the estimated optimum knee joint angle was larger for the Taekwondo athletes compared with the non-athlete group ($78.47{\pm}5.14^{\circ}$ and $67.54{\pm}5.77^{\circ}$, respectively; p<.05). Conclusion : The results of this study suggests that, compared with non-athletes, Taekwondo athletes have stronger knee extensor strength at all hip-knee joint angle combinations as well as longer optimum muscle length, which might be optimized for the event-specific required performance through prolonged training period.

• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.183-203
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• 2002

To know the effect of index of social ability (ISA) and function of social life (FSL) with activities of daily living (ADL) and instrumental activities of daily living (IADL), we carried out a study on the elderly with osteoarthritis daily living in Daegu city for 4 months, from April to July 2002. The followings were observed: 1. The score of functional disability of knee, ADL and ISA were better at lower age (p < 0.01). 2. The younger they are, the better FSL they have. The lower age group has good FSL (p < 0.01). 3. Weight affects more to the under 49Kg group than 50-59Kg group and 60-69Kg group in functional disability of knee, while it doesn't make much difference for the other groups (p > 0.05) and other assessment index doesn't show any relationship with weight. 4. Regarding relat ionship with height , taller group has better knee functions: it's proved by post hock examination that the over 160cm group has much higher knee function than the other groups (p < 0.05). In case of ADL, the over 160cm group and under 149cm group were better than 150$\∼$159cm group. (p < 0.01) . 5. ISA was also different depending on height . It was proved that FSL was the better for the over 160cm group than for the others as a result of post hock examination (p < 0.05). 6. In regard of how many months have passed since the attack of functional disability of knee, knee joint function was better for the 12mon$\∼$36mon group than for the others and the score of ADL was lower for the 12mon$\∼$36mon group than for the others (p < 0.01). ISA was lower for the 12mon$\∼$36mon group and the under 6mon group than for the other groups (p < 0.01). FSL was lower for the 12mon$\∼$36mon group and the under 6mon group than the other groups. (p < 0.01). 7. Comparing left knee with right one, the problem with left knee has lower score of functional disability in all items (p < 0.01). 8. Considering friction noise, knee joint function was slightly better for non-friction noise-group, but it's not statistically significant though. ADL and ISA were better for non-friction noise-group (p < 0.01), while no statistical significance was found in FSL, 9. Knee joint function was better for the group who doesn't have limitation on range of knee flexion motion (p,0.05) but no other difference was found in other items from this group. 10. Limitation on range of knee flexion motion has no statistical difference in ADL and FSL. However, ISA was better for the non-limitation group (p < 0.05) . 11. Knee joint function score has high correlation with ISA (r=0.812, p < 0.01) and FSL (r=0.732, p < 0.01) , which shows the better knee joint function, the higher the score. 12. ISA and FSL were highly correlated: the better ISA, the better FSL (r=0.893, p < 0.01), while ADL has no correlation with either knee joint function or ISA or FSL.

• Physical Therapy Korea
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• v.23 no.4
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• pp.1-8
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• 2016

Background: Various methods are used for recovery of knee flexion range of motion (ROM) due to a tightened rectus femoris muscle (RFM) or limited inferior glide of the patella. Stretching methods are common interventions for restoring the tightened RFM length. Also patellar inferior gliding (PIG) technique can recover tightened RFM length too. However, effect of applying the PIG to passive knee flexion (PKF) has not been studied. Objects: The purpose of this study was to investigate the effect of combining PIG with RFM stretching for improving knee flexion ROM in subjects with RFM tightness. Methods: Twenty-six subjects with RFM tightness were recruited. Two different methods of knee stretching were tested: 1) PKF during modified Thomas test (MTT) and 2) PKF with PIG during MTT. The passive stretching forces was controlled by hand-held dynamometer. The knee flexion ROM angle was measured by a MTT with ImageJ software. Differences between the conditions with and without PIG were identified with a paired t-test. Results: The knee flexion ROM was significantly greater for PKF with PIG ($114.44{\pm}9.33$) than for PKF alone ($108.97{\pm}9.42$) (p<.001). Conclusion: A combination of passive knee flexion exercise and PIG can be more effective than PKF in increasing knee flexion ROM in individuals with RFM tightness.