Novel Method of Classification in Knee Osteoarthritis: Machine Learning Application Versus Logistic Regression Model

Objective@#To present new classification methods of knee osteoarthritis (KOA) using machine learning and compare its performance with conventional statistical methods as classification techniques using machine learning have recently been developed. @*Methods@#A total of 84 KOA patients and 97 normal participants were recruited. KOA patients were clustered into three groups according to the Kellgren-Lawrence (K-L) grading system. All subjects completed gait trials under the same experimental conditions. Machine learning-based classification using the support vector machine (SVM) classifier was performed to classify KOA patients and the severity of KOA. Logistic regression analysis was also performed to compare the results in classifying KOA patients with machine learning method. @*Results@#In the classification between KOA patients and normal subjects, the accuracy of classification was higher in machine learning method than in logistic regression analysis. In the classification of KOA severity, accuracy was enhanced through the feature selection process in the machine learning method. The most significant gait feature for classification was flexion and extension of the knee in the swing phase in the machine learning method. @*Conclusion@#The machine learning method is thought to be a new approach to complement conventional logistic regression analysis in the classification of KOA patients. It can be clinically used for diagnosis and gait correction of KOA patients.

Novel Method of Classification in Knee Osteoarthritis: Machine Learning Application Versus Logistic Regression Model

Objective@#To present new classification methods of knee osteoarthritis (KOA) using machine learning and compare its performance with conventional statistical methods as classification techniques using machine learning have recently been developed. @*Methods@#A total of 84 KOA patients and 97 normal participants were recruited. KOA patients were clustered into three groups according to the Kellgren-Lawrence (K-L) grading system. All subjects completed gait trials under the same experimental conditions. Machine learning-based classification using the support vector machine (SVM) classifier was performed to classify KOA patients and the severity of KOA. Logistic regression analysis was also performed to compare the results in classifying KOA patients with machine learning method. @*Results@#In the classification between KOA patients and normal subjects, the accuracy of classification was higher in machine learning method than in logistic regression analysis. In the classification of KOA severity, accuracy was enhanced through the feature selection process in the machine learning method. The most significant gait feature for classification was flexion and extension of the knee in the swing phase in the machine learning method. @*Conclusion@#The machine learning method is thought to be a new approach to complement conventional logistic regression analysis in the classification of KOA patients. It can be clinically used for diagnosis and gait correction of KOA patients.

Evaluation of Validity and Reliability of Inertial Measurement Unit-Based Gait Analysis Systems

OBJECTIVE: To replace camera-based three-dimensional motion analyzers which are widely used to analyze body movements and gait but are also costly and require a large dedicated space, this study evaluates the validity and reliability of inertial measurement unit (IMU)-based systems by analyzing their spatio-temporal and kinematic measurement parameters. METHODS: The investigation was conducted in three separate hospitals with three healthy participants. IMUs were attached to the abdomen as well as the thigh, shank, and foot of both legs of each participant. Each participant then completed a 10-m gait course 10 times. During each gait cycle, the hips, knees, and ankle joints were observed from the sagittal, frontal, and transverse planes. The experiments were conducted with both a camerabased system and an IMU-based system. The measured gait analysis data were evaluated for validity and reliability using root mean square error (RMSE) and intraclass correlation coefficient (ICC) analyses. RESULTS: The differences between the RMSE values of the two systems determined through kinematic parameters ranged from a minimum of 1.83 to a maximum of 3.98 with a tolerance close to 1%. The results of this study also confirmed the reliability of the IMU-based system, and all of the variables showed a statistically high ICC. CONCLUSION: These results confirmed that IMU-based systems can reliably replace camera-based systems for clinical body motion and gait analyses.

Change in Musculoskeletal Pain in Patients With Work-Related Musculoskeletal Disorder After Tailored Rehabilitation Education: A One-Year Follow-Up Survey

OBJECTIVE: To apply tailored rehabilitation education to video display terminal (VDT) workers with musculoskeletal pain and to assess changes in musculoskeletal pain after rehabilitation education. METHODS: A total of 8,828 VDT workers were screened for musculoskeletal disorders using a self-report questionnaire. Six hundred twenty-six VDT workers selected based on their questionnaires were enrolled in musculoskeletal rehabilitation education, which consisted of education on VDT syndrome and confirmed diseases, exercise therapy including self-stretching and strengthening, and posture correction. One year later, a follow-up screening survey was performed on 316 VDT workers, and the results were compared with the previous data. RESULTS: Compared with the initial survey, pain intensity was significantly decreased in the neck area; pain duration and frequency were significantly decreased in the low back area; and pain duration, intensity, and frequency were significantly decreased in the shoulder and wrist after tailored rehabilitation education. In addition, pain duration, intensity, and frequency showed a greater significant decrease after tailored rehabilitation education in the mild pain group than in the severe pain group. CONCLUSIONS: This study found that work-related musculoskeletal pain was reduced after tailored rehabilitation education, especially in the shoulder, wrist, and low back.

Slip-Related Changes in Plantar Pressure Distribution, and Parameters for Early Detection of Slip Events

OBJECTIVE: To investigate differences in plantar pressure distribution between a normal gait and unpredictable slip events to predict the initiation of the slipping process. METHODS: Eleven male participants were enrolled. Subjects walked onto a wooden tile, and two layers of oily vinyl sheet were placed on the expected spot of the 4th step to induce a slip. An insole pressure-measuring system was used to monitor plantar pressure distribution. This system measured plantar pressure in four regions (the toes, metatarsal head, arch, and heel) for three events: the step during normal gait; the recovered step, when the subject recovered from a slip; and the uncorrected, harmful slipped step. Four variables were analyzed: peak pressure (PP), contact time (CT), the pressure-time integral (PTI), and the instant of peak pressure (IPP). RESULTS: The plantar pressure pattern in the heel was unique, as compared with other parts of the sole. In the heel, PP, CT, and PTI values were high in slipped and recovered steps compared with normal steps. The IPP differed markedly among the three steps. The IPPs in the heel for the three events were, in descending order (from latest to earliest), slipped, recovered, and normal steps, whereas in the other regions the order was normal, recovered, and slipped steps. Finally, the metatarsal head-to-heel IPP ratios for the normal, recovered, and slipped steps were 6.1+/-2.9, 3.1+/-3.0, and 2.2+/-2.5, respectively. CONCLUSION: A distinctive plantar pressure pattern in the heel might be useful for early detection of a slip event to prevent slip-related injuries.

Appropriate Depth of Needle Insertion During Rhomboid Major Trigger Point Block

OBJECTIVE: To investigate an appropriate depth of needle insertion during trigger point injection into the rhomboid major muscle. METHODS: Sixty-two patients who visited our department with shoulder or upper back pain participated in this study. The distance between the skin and the rhomboid major muscle (SM) and the distance between the skin and rib (SB) were measured using ultrasonography. The subjects were divided into 3 groups according to BMI: BMI less than 23 kg/m2 (underweight or normal group); 23 kg/m2 or more to less than 25 kg/m2 (overweight group); and 25 kg/m2 or more (obese group). The mean+/-standard deviation (SD) of SM and SB of each group were calculated. A range between mean+1 SD of SM and the mean-1 SD of SB was defined as a safe margin. RESULTS: The underweight or normal group's SM, SB, and the safe margin were 1.2+/-0.2, 2.1+/-0.4, and 1.4 to 1.7 cm, respectively. The overweight group's SM and SB were 1.4+/-0.2 and 2.4+/-0.9 cm, respectively. The safe margin could not be calculated for this group. The obese group's SM, SB, and the safe margin were 1.8+/-0.3, 2.7+/-0.5, and 2.1 to 2.2 cm, respectively. CONCLUSION: This study will help us to set the standard depth of safe needle insertion into the rhomboid major muscle in an effective manner without causing any complications.

The Effect of Two Different Hand Exercises on Grip Strength, Forearm Circumference, and Vascular Maturation in Patients Who Underwent Arteriovenous Fistula Surgery

OBJECTIVE: To compare the effect of two different hand exercises on hand strength and vascular maturation in patients who underwent arteriovenous fistula surgery. METHODS: We recruited 18 patients who had chronic kidney disease and had undergone arteriovenous fistula surgery for hemodialysis. After the surgery, 10 subjects performed hand-squeezing exercise with GD Grip, and other 8 subjects used Soft Ball. The subjects continued the exercises for 4 weeks. The hand grip strength, pinch strength (tip, palmar and lateral pinch), and forearm circumference of the subjects were assessed before and after the hand-squeezing exercise. The cephalic vein size, blood flow velocity and volume were also measured by ultrasonography in the operated limb. RESULTS: All of the 3 types of pinch strengths, grip strength, and forearm circumference were significantly increased in the group using GD Grip. Cephalic vein size and blood flow volume were also significantly increased. However, blood flow velocity showed no difference after the exercise. The group using Soft Ball showed a significant increase in the tip and lateral pinch strength and forearm circumference. The cephalic vein size and blood flow volume were also significantly increased. On comparing the effect of the two different hand exercises, hand-squeezing exercise with GD Grip had a significantly better effect on the tip and palmar pinch strength than hand-squeezing exercise with Soft Ball. The effect on cephalic vein size was not significantly different between the two groups. CONCLUSION: The results showed that hand squeezing exercise with GD Grip was more effective in increasing the tip and palmar pinch strength compared to hand squeezing exercise with soft ball.

Generalized Joint Hypermobility in Healthy Female Koreans: Prevalence and Age-Related Differences

OBJECTIVE: Objective To evaluate the prevalence of generalized joint hypermobility (GJH) in healthy female Koreans and to determine whether the degree of GJH differs between children and adults. METHODS: Two groups of females were enrolled, a group of girls from an elementary school (n=404) and women from a call center (n=266). GJH was diagnosed using the Beighton score, which is composed of an evaluation of bilateral knees, elbows, thumbs, and fifth fingers as well as thoracolumbar joint. The GJH and localized hypermobility of each joint was compared between the two groups, and the pattern of hypermobility according to age and dominant hand was investigated. RESULTS: Total prevalence of GJH was 50.0% (335/750), and it was more frequently observed in the group of girls (58.9%, 238/404) than women (36.5%, 97/266). The degree of GJH expressed in terms of Beighton score was inversely correlated with age (p<0.05). Significant differences in localized hypermobility of the thumb and fifth finger were found between the two groups and were postulated as the cause for the decline in GJH with age. The pattern of decreased mobility proportional to aging differed between the two joints. Decreased mobility occurred equally on both sides of the thumb but was biased toward the fifth finger of the dominant side (mostly the right). CONCLUSION: The female Koreans appeared to have a high prevalence of GJH. The incidence of GJH decreased as age increased as a result of decreased mobility of the fifth finger on the dominant side.

Causes of Hand Tingling in Visual Display Terminal Workers

OBJECTIVE: To offer the basic data about the causes and distribution of hand tingling, symptoms and physical findings, and pressure pain threshold in desk workers. METHODS: Five physiatrists participated in the screening test composed of history and physical examination. A total of 876 desk workers were evaluated and of them 37 subjects with hand tingling were selected. For further analyzing, detailed history taking and meticulous physical examination were taken. Pressure pain threshold (PPT) at the infraspinatus, upper trapezius, flexor carpi radialis, rhomboideus, and flexor pollicis longus were examined. PPT measurements were repeated three times with two minute intervals by a pressure algometer. Electrodiagnostic study was done to detect potential neurologic abnormalities. RESULTS: The causes of hand tingling in order of frequency were: myofascial pain syndrome, 68%; cervical radiculopathy, 27%; rotator cuff syndrome, 11%; tenosynovitis, 8%; and carpal tunnel syndrome, 5%. The location of trigger points in the myofascial pain syndrome, which were proven to evoke a tingling sensation to the hand in order of frequency were: infraspinatus, 65.4%; upper trapezius, 57.7%; flexor carpi radialis, 38.5%; rhomboideus 15.4%; and flexor pollicis longus 11.5%. The PPT of the affected side was significantly lower than that of the unaffected side in myofascial pain syndrome (p<0.05). CONCLUSION: The most common cause of hand tingling in desk workers was myofascial pain syndrome rather than carpal tunnel syndrome. Common trigger points to evoke hand tingling were in the infraspinatus and upper trapezius.

The Prevalence and Characteristics of Depression in Work-related Musculoskeletal Disease

OBJECTIVE: To reveal the relationship between depression and WMSD. METHOD: Five physiatrists participated in the workplace musculoskeletal survey and diagnosed 724 office workers with WMSD by performing detailed history taking and physical examination. All subjects were asked to answer the Korean version of the Beck depressive inventory (K-BDI), and to express their pain according to the visual analogue scale (VAS) score. We categorized the subjects into 4 groups, myofascial pain syndrome (MPS), herniated intervertebral disk (HIVD), tenosynovitis, and others, and investigated the prevalence of depression in desk workers and relationship between WMSD and depression, and we compared pain intensity between the depression and non-depression groups. Correlation analysis was carried out between K-BDI and VAS scores in each group. RESULTS: The mean K-BDI score were 8.7+/-6.68. The prevalence of depression was higher in females than in male, and there was no relationship between age and depression. There was a significant connection between HIVD and depression (p<0.05). However, the other groups did not have significant connection to depression. The VAS score (5.02) of the depression group was significantly higher than that (4.10) of the non-depression group. In addition, there was a significant difference of VAS scores between the depression group and non-depression group in each disease group. CONCLUSION: The mean VAS score of the depression group in WMSD was significantly higher than in the non-depression group. The correlation between BDI and VAS scores in the subjects was present, and the highest was in the HIVD group.

The Effect of Leflunomide on Cold and Vibratory Sensation in Patients with Rheumatoid Arthritis

OBJECTIVE: To evaluate the prevalence and risk factors of peripheral neuropathy in patients with rheumatoid arthritis (RA) treated with leflunomide (LEF) by quantitative sensory testing (QST). METHOD: A total of 94 patients were enrolledin this study, out of which 47 patients received LEF. The other 47 patients received alternative disease-modifying antirheumatic drugs and served as the control group. The demographic characteristics, laboratory findings, concomitant diseases, and medication history were evaluated at the time of QST. The cooling (CDT) and vibratory detection threshold (VDT) as the representative components of QST were measured. RESULTS: Age, gender, RA duration, ESR, and CRP did not show any significant differences between the two groups. VDT did not demonstrate any significant difference in both groups. However, CDT in LEF group was significantly higher than that of the control group (8.6+/-2.7 in LEF vs. 5.6+/-3.8 in control). The proportion of RA patients in the LEF group showing abnormally high CDT was over 2 times greater than that of the control group, but these findings were not statistically significant. Age, RA duration (or LEF medication in LEF group), ESR, and CRP did not show significant correlation with CDT in both groups. VDT significantly correlated with age in both groups. CONCLUSION: LEF treatment in patients with RA may lead to abnormal CDT in QST. CDT value was not affected by age, RA duration, disease activity, or LEF duration. It remains to be determined whether QST may be a valuable non-invasive instrument to evaluate the early sensory changes in patients with RA taking LEF.

The Influence of Backrest Inclination on Buttock Pressure

OBJECTIVE: To assess the effects of backrest inclination of a wheelchair on buttock pressures in spinal cord injured (SCI) patients and normal subjects. METHOD: The participants were 22 healthy subjects and 22 SCI patients. Buttock pressures of the participants were measured by a Tekscan(R) pressure sensing mat and software while they were sitting in a reclining wheelchair. Buttock pressures were recorded for 90degrees, 100degrees, 110degrees, 120degrees and 130degrees seat-to-back angles at the ischial tuberosity (IT) and sacrococcygeal (SC) areas. Recordings were made at each angle over four seconds at a sampling rate of 10 Hz. RESULTS: The side-to-side buttock pressure differences in the IT area for the SCI patients was significantly greater than for the normal subjects. There was no significant difference between the SCI patients and the normal subjects in the buttock pressure change pattern of the IT area. Significant increases in pressure on the SC area were found as backrest inclination angle was changed to 90degrees, 100degrees and 110degrees in the normal subjects, but no significant differences were found in the SCI patients. CONCLUSION: Most of the SCI patients have freeform posture in wheelchairs, and this leads to an uneven distribution of buttock pressure. In the SCI patients, the peak pressure in the IT area reduced as the backrest angle was increased, but peak pressure at the SC area remained relatively unchanged. To reduce buttock pressure and prevent pressure ulcers and enhance ulcer healing, it can be helpful for tetraplegic patients, to have wheelchair seat-to-back angles above 120degrees.

Reliability and Usefulness of the Pressure Pain Threshold Measurement in Patients with Myofascial Pain

OBJECTIVE: To assess the usefulness of a pressure algometer to measure pressure pain threshold (PPT) for diagnosis of myofascial pain syndrome (MPS) in the upper extremity and trunk muscles. METHOD: A group of 221 desk workers complaining of upper body pain participated in this study. Five physiatrists made the diagnosis of MPS using physical examination and PPT measurements. PPT measurements were determined for several muscles in the back and upper extremities. Mean PPT data for gender, side, and dominant hand groups were analyzed. Sensitivity and specificity of Fischer's standard method were evaluated. PPT cut-off values for each muscle group were determined using an ROC curve. RESULTS: Cronbach's alpha for each muscle was very high. The PPT in men was higher than in females, and the PPT in the left side was higher than in the right side for all muscles tested (p<0.05). There was no significant difference in PPT for all muscles between dominant and non-dominant hand groups. Diagnosis of MPS based on Fischer's standard showed relatively high specificity and poor sensitivity. CONCLUSION: The digital pressure algometer showed high reliability. PPT might be a useful parameter for assessing a treatment's effect, but not for use in diagnosis or even as a screening method.

Electromyographic Analysis of Left Leg Muscle Activity during Golf Driver Swing

OBJECTIVE: To analyze activities of left lower extremity muscles throughout phases of the golf swing, using surface electromyography. METHOD: We evaluated muscle activities during the golf swing of 5 amateur and 5 professional golfers using surface electromyography. Surface electrodes were placed in the left gluteus medius, gluteus maximus, biceps femoris, gastrocnemius, rectus femoris, peroneus longus, and tibialis anterior. RESULTS: Muscle activities of professional golfers in the left gluteus medius, gluteus maximus, biceps femoris, tibialis anterior, rectus femoris abruptly increased from top-swing phase to impact phase but muscle activities of amateur golfers in these muscles increased to top-swing phase and decreased at follow swing phase. Muscle activities of professional golfers in left peroneus longus, gastrocnemius abruptly increase from forward swing to impact but muscle activity of amateur golfers in these muscles continuously increase to impact and abruptly increase at follow swing. CONCLUSION: Our findings demonstrate the importance of the muscles in the golfer's swing.

Health-Related Quality of Life and Upper Extremity Pain in Workers Using Computer

OBJECTIVE: To investigate the relationship between health-related quality of life (HRQOL) and upper extremity pain in workers using computer. METHOD: Ten thousand four hundred office workers using computer over 4 hours per day were enrolled, and two self-reported questionnaires were given to each candidate. First questionnaire included questions on location, duration, frequency and severity of pain, gender, age and history of alcohol, smoking and exercise. Second questionnaire used Korean job stress measurement scale (KJSMS) and medical outcome study 36 item short form health survey (SF-36) for assessing HRQOL. A total of 6,669 workers took part in interview. RESULTS: Mean age of group with pain was lower than that of painless group. Male gender, working period of 11~20 years, and smoking were associated with musculoskeletal pain, and similar result was found in group with no alcohol consumption, no exercise, and house chores for more than 2 hours per day. The short working period was associated with higher KJSMS Short Form score. For shoulder pain, only duty self-control showed significant difference according to pain scale in KJSMS. When adjusted with age, gender, working period, house chores and history of alcohol and smoking, there was no significant difference between musculoskeletal symptom and KJSMS, SF-36, respectively. CONCLUSION: Only shoulder pain and duty self-control score were related factors, comparing subjective symptoms of musculoskeletal pain and job stress. Additional investigation using strict definition and diagnostic criteria should be performed.

The Relationship between Korean Version of Falls Efficacy Scale - International and Frequency of Falls in the Healthy Elderly Visiting the Public Health Centers

OBJECTIVE: To see whether there is a relationship between Korean Falls Efficacy Scale-International (KFES-I) developed for measuring fear of falling and frequency of fall. METHOD: KFES-I was composed with 16 items of activities of daily living including social activities and graded from 1 to 4 in each item. Surveys of 250 patients over 65 years of age from the public health center of Kang-dong and Seong-buk based on KFES-I and fall questionnaire such as presence, frequency and severity of fracture within last 6 months, and combined medical illness were taken. The data of KFES-I, fall questionnaire, and the inter-relationship of KFES-I items had been analyzed by Spearman and Kendall test. RESULTS: There was strong positive correlation between KFES-I total score and the frequency of falls. Four items (item 4, 7, 11, 15) of KFES-I showed strong correlation with the frequency of falls. There was significant difference in KFES-I total score between control and fracture groups (p<0.05). CONCLUSION: Our results showed that there was strong positive correlation between frequency of falls and KFES-I. It is suggested that frequency of falls can be predicted by KFES-I.

Development of Korean Academy of Medical Sciences Guideline-Rating the Impairment in Pain

Pain-related impairment assessment by the fifth edition of the American Medical Association Guides had many ambiguous points, and therefore, it was not applicable directly in Korea. Several disputable pain disorders were excluded from the list of impairment evaluation, and complex regional pain syndrome was chosen as the first object of impairment evaluation. Scales such as Korean version of modified Barthel index for assessing the activity of daily livings and Beck Depression Inventory for assessing depression were added, and pain severity, pain treatment, pain behavior, etc. were scored. In order to objectify as much as possible and to remove the room for misuse, we develop a new rating system based on the concept of total score.

Risk Factor, Job Stress and Quality of Life in VDT Workers with Low Back Pain

OBJECTIVE: To investigate symptom prevalence, risk factor, and relationship between job stress and health-related quality of life in visual display terminal (VDT) workers with low back pain. METHOD: 5,005 people aged from 28 to 59 without neck or upper extremity pain, were enrolled and their general characteristics, working period, personal history like smoking, drinking, type of leisure and average housework time were collected via a questionnaire survey. The job stress and the health-related quality of life were measured by using the Korean Occupational Stress Scale (KOSS) and the Korean Short Form Health Survey-36 (KSF-36) respectively. The relationship between general characteristics, working period, personal history, KOSS score, and KSF-36 score were statistically analyzed. RESULTS: The average age of questionnaire respondents was 43.4 years old. Twenty-seven and ninety-one (2,791) VDT workers responded to have experienced low back pain in past 1 year. The symptom prevalence was 58.2%. The KOSS score of all VDT workers was higher than reference range. There were moderate negative correlations between KOSS score and subscale score of KSF-36 like vitality, mental health, and mental component summary in all groups. In a multivariate analysis of all subjects, younger age, female, type of leisure except sports activity, and feeling of body loading were independently associated with low back pain of VDT workers. CONCLUSION: This study provides the basic data about the relationship between job stress and health-related quality of life of VDT workers as well as risk factors of low back pain in VDT workers.

Development of the Korean Academy of Medical Sciences Guideline for Rating the Impairment in the Brain Injured and Brain Diseased Persons with Motor Dysfunction

To develop an objective and scientific method to evaluate the brain injured and brain diseased persons with motor dysfunction, American Medical Association's Guides to the Evaluation of Permanent Impairment was used as an exemplar. After the motor dysfunction due to brain injury or brain disease was confirmed, active range of motion and muscle strength of affected extremities were measured. Also, the total function of extremities was evaluated through the assessment of activities of daily living, fine coordination of hand, balance and gait. Then, the total score of manual muscle test and functional assessment of impaired upper and lower extremity were added, respectively. Spasticity of upper and lower extremity was used as minus factors. Patients with movement disorder such as Parkinson's disease were assessed based on the degree of dysfunction in response to medication. We develop a new rating system based on the concept of total score.

Effects of Stretching Exercise on the Head Speed of Golf Club and Driving Distance

OBJECTIVE: To evaluate the effects of stretching exercise on the head speed of golf club and driving distance. METHOD: 58 male golfers (20 professionals, 22 amateurs, 16 beginners) were included in the study. They carried out stretching exercise programs related to muscles of trunk, upper and lower extremities for 5 and 30 minutes. The head speed of golf club and driving distance were measured before and after the stretching exercise. The effects of stretching exercise programs on the head speed and driving distance were assessed. RESULTS: The head speed increased significantly in amateur and beginner groups after 30 minutes' stretching. In professional group, the head speed increased significantly after 5 minutes' stretching, but no more increment was found after 30 minutes' stretching. Driving distance increased significantly in all groups after 5 minutes' stretching. After 30 minutes' stretching, much more increment was found compared to 5 minutes' stretching. CONCLUSION: Sufficient stretching exercise program before golf swing can increase the head speed of club and driving distance. We recommend stretching exercise to improve golf performance.