Posteromedial vertical capsulotomy selectively expands the intraoperative extension gap in cruciate-retaining total knee arthroplasty.

PURPOSE: Effective soft-tissue balancing procedures for expanding the extension gap (EG) are needed in cases of gap mismatch in total knee arthroplasty (TKA). A posteromedial vertical capsulotomy (PMVC) is performed to restore mobility in a knee with a flexion contracture. The purpose of this study was to evaluate the effectiveness and safety of PMVC for intraoperative gap adjustment in cruciate-retaining TKA. METHODS: A total of 120 consecutive knees undergoing cruciate-retaining TKA for varus osteoarthritis were examined. The EG and flexion gap (FG) with a trial femoral component were measured using spacer blocks before and after PMVC. PMVC was performed when the first FG was larger than the first EG by > 2 mm. RESULTS: Sixty-five knees underwent PMVC, and the mean EG significantly increased by 2.4 mm (p < 0.001). This increase was significantly larger than that of the FG by 2.0 mm (p < 0.001). The preoperative extension range of motion (ROM) was negatively correlated with the EG change after PMVC (r = - 0.39, p = 0.001). A receiver operating characteristic (ROC) curve indicated a preoperative extension ROM cut-off of -10° for predicting PMVC (sensitivity 72.3%, specificity 56.4%). No associated complications were observed during a minimum 2-year follow-up period, and there was no difference in the postoperative Knee Society Score between the PMVC and non-PMVC groups. CONCLUSION: PMVC may be a useful soft-tissue treatment for gap adjustment with a selective EG expansion in TKA, especially in cases of a limited preoperative extension of - 10° or less. LEVEL OF EVIDENCE: Therapeutic study, level III.

The impact of the foot contact position and cutting angle during cutting on the risk of anterior cruciate ligament injury.

[Purpose] This study aimed to clarify the impact of the foot contact position and cutting angle on the risk of anterior cruciate ligament injury during cutting. [Participants and Methods] Seven healthy males performed cuttings under four tasks by changing the foot contact position and cutting angle. A three-dimensional motion analysis system and force plates were used for taking measurements. The peak vertical ground reaction force and loading rate were calculated. The pelvic, hip, and knee joint angles were measured at the peak vertical ground reaction force. [Results] The loading rate was significantly higher in the lateral foot contact than in the anterior foot contact when the cutting angle was large. The knee flexion angle at the peak vertical ground reaction force was significantly smaller in the lateral foot contact than in the anterior foot contact when the cutting angle was large, similar to the pelvic forward inclination angle, regardless of the foot contact position. [Conclusion] As the cutting angle increased, the knee flexion and pelvic forward inclination angles decreased, resulting in an increase in the loading rate during cutting with the lateral foot contact. Therefore, an increase in the cutting angle can increase the risk of anterior cruciate ligament injury.

The relationship between the deep squat movement and the hip, knee and ankle range of motion and muscle strength.

[Purpose] We examined and clarified the relationship between the maximum squat depth and the range of motion of the ankle, knee, and hip joints, and the knee and hip muscle strength. [Participants and Methods] Nine healthy males participated in this study and performed a deep squat with the upper extremities raised; the movement was analyzed by two-dimensional motion analysis. We measured the ankle dorsiflexion, hip flexion, and knee flexion ranges of motion, as well as the knee extension and hip flexion muscle strengths and analyzed the relationship between the squatting motion, the range of motion, and the muscle strength of each joint. [Results] The right ankle dorsiflexion range of motion was a significant predictor of the ankle dorsiflexion angle on both sides. The right knee flexion range of motion was a significant predictor of the knee flexion angle, and the left knee flexion range of motion was a significant predictor of the trunk anterior tilt angle on both sides. The right ankle dorsiflexion range of motion was a significant predictor of the right hip flexion angle and vice versa. [Conclusion] This study reveals that movement on one side affects contralateral movement, which is important when evaluating the deep squat motion as a functional test.

Reliability and validity of the Mongolian version of the Zarit Caregiver Burden Interview.

[Purpose] Our study aimed to verify the reliability and validity of the translated Mongolian version of the Zarit Caregiver Burden Interview (ZBI). [Participants and Methods] We obtained the basic information of patients and their caregivers when they were hospitalized (Study 1). Subsequently, after the hospital discharged the patients, the caregivers answered the ZBI by telephone during the 4th and 5th weeks (Studies 2 and 3, respectively). To evaluate reliability, we calculated the correlation coefficient, compared the total scores of the ZBI obtained in Studies 2 and 3, and calculated Cronbach's alpha coefficient. To evaluate validity, we calculated the correlation coefficient of the score of item 22 and the sum of the scores of items 1-21. [Results] The correlation coefficient for reliability was high, and the difference between the two studies was insignificant. Cronbach's alpha coefficient was 0.92. The correlation coefficient was high for validity as well. [Conclusion] The Mongolian version of the ZBI has high reliability and validity.

Fact-finding survey regarding judo-related injuries of judokas in developing country.

[Purpose] The purpose of this study was to investigate sports-related injuries among judokas in Mongolia which is classified in the lower-middle income country. This study may help prevent future sports-related injuries. [Participants and Methods] We studied 75 judokas affiliated to the judo club in Ulaanbaatar, Mongolia. The questionnaire survey included questions regarding current and past judo-related injuries. [Results] Out of 75 judokas, 39% judokas had current judo-related injuries, and 25% judokas had past injuries. The injuries were most commonly located in the shoulder/clavicular, followed by that in the ankle and knee. The most frequent injury was a sprain/ligament injury, followed by a fracture and a dislocation. Seventy-three percent of current injuries and 88% of the past injuries received medical attention. Self-management was carried out for 35% of the injuries. The time lost from judo matches and training was 0-1,095 days for current injuries and 0-545 days for past injuries. [Conclusion] In this study, the injury rate for judokas was higher than that reported in previous studies. In addition, numerous severe injuries were noted. It is observed that, despite medical attention and self-management, the recovery periods are prolonged. Additionally, we believe that the judokas are unable to return to competition without problems.

Shoulder and elbow pain in junior high school baseball players: Results of a nationwide survey.

BACKGROUND: Despite proposals and guidelines to prevent baseball injuries in young players by societies and organizations, many shoulder and elbow injuries continue to occur among junior high school baseball players. In order to investigate the training conditions of junior high school baseball players and the risk factors for shoulder and elbow pain in the players, we conducted a questionnaire survey among junior high school baseball players throughout the country. METHODS: The questionnaire survey was conducted among junior high school baseball players in September 2016. RESULTS: A total of 11,134 junior high school baseball players belonging to 495 teams responded to the survey. Among these, 4004 players trained every day of the week and 1151 players played baseball games every month with no off-season. Among 9752 players who did not have shoulder and/or elbow pain in the spring and summer of 2015, 19.2% of players experienced elbow pain over the course of one year, 13.6% of players experienced shoulder pain, and 28.0% complained of shoulder and/or elbow pain. The frequency of elbow pain was more than that of shoulder pain. At risk for shoulder pain were pitchers and catchers and second-year students, while risk factors for elbow pain were playing pitcher and catcher positions, pitching or throwing ≥300 balls per week, playing ≥10 games on average per month and being left-handed. CONCLUSION: Risk factors for shoulder pain were different from those for elbow pain. To prevent elbow pain, coaches should pay attention to pitchers and catchers and left-handed players and not allow players to pitch or throw ≥300 full-power balls per week or participate in ≥10 games per month. They should also pay attention to pitchers and catchers and second-year students to prevent shoulder pain. It is important for coaches to train multiple pitchers and catchers.

Analysis of lower extremity side-reaching motion in junior high school baseball players.

[Purpose] The aim of this study was to clarify the movement pattern of the pelvis and trunk of junior high school baseball players based on the lateral reach motion of the lower limb, which is related to poor pitching movement. [Participants and Methods] Twenty-five male students belonging to a baseball club participated in this study. Each participant performed the lower limb side reach movement in the standing position, during which the movements of the knee joint, hip joint, pelvis, and trunk were analyzed. [Results] A significant correlation was found between reach distance and reach leg hip abduction, supporting leg hip abduction, trunk side bending, and trunk tilt. We found a significant correlation between reach leg hip abduction and pelvic tilt and trunk side bending and between supporting leg hip abduction and pelvic tilt, knee valgus, and trunk side bending. Furthermore, we found a significant correlation between knee valgus and lower leg tilt and trunk tilt and between trunk side bending and pelvic tilt. [Conclusion] This study suggests that in the standing position movement at this age, the hip and trunk movements are related to and affect performance.

Retrospective survey of sport climbing injuries and self-care in the Gunma prefecture.

[Purpose] This study aimed to investigate sport climbing injuries among users of a climbing gym to identify the characteristics of the injuries and preventive measures. [Participants and Methods] Participants with at least 6 months of sport climbing experience at least once a week were included in the study. They provided basic information with regard to climbing, medical history, and self-care of climbing-related injuries. [Results] Of 113 validated respondents, 85 reported a history of climbing-related injuries. The injury occurrence rate by location was highest in the fingers, followed by the wrist, shoulder and ankle, knee, and elbow. All the ankle injuries had sudden onset. Moreover, the occurrence rates of the injuries with both sudden and gradual onsets tended to be higher in the fingers and wrists. With regard to the self-care status, warming up was performed by 88.5% of the participants; and cooling down, by only 25.7%. [Conclusion] This study found a high incidence of injuries involving the fingers, wrists, and ankles, which suggests the need for prevention by self-care.

Characteristics of counter-movements in sport climbing: a comparison between experienced climbers and beginners.

[Purpose] This study aimed to evaluate the movement characteristics of sport climbing on the basis of the difference in basic movements between experienced climbers and beginners. [Participants and Methods] Eighteen healthy men participated in this study, including 9 experienced climbers and 9 beginners. A two-dimensional motion analysis was conducted with two digital cameras. The motion tasks were the counter-movements, including before and after each movement, which was classified into 5 phases. In each phase, the joint angles of the shoulder, elbow, hip, knee, and trunk were calculated. In the frontal plane, the center of gravity (COG) trajectory, motion speed, and motion time were calculated, which were compared between the climbers and the beginners in each phase. [Results] A significant difference was observed in the horizontal direction of the COG movement width. The beginners tended to have smaller shoulder flexion and abduction, and larger elbow flexion on the supporting side, and smaller hip flexion and abduction and knee flexion on the support side than the climbers. [Conclusion] This study suggests that climbers adopt a strategy to reduce the burden on the upper extremities by efficiently using the trunk and lower extremities to move their COG.

Intra-rater reliability and criterion-related validity of using an accelerometer to measure the impact force and knee joint sway during single-leg drop landing.

[Purpose] This study aimed to clarify the reliability and validity of the impact force and knee joint sway measurement during single-leg drop landing by using a motion sensor with two built-in accelerometers. [Participants and Methods] Ten healthy college students (4 males and 6 females) who joined a basketball club participated in this study. Peak vertical acceleration, time between initial contact and peak vertical acceleration, and knee joint mediolateral sway were measured using the accelerometer during the landing motion. Reliability of the measurement with the accelerometer and the criterion-related validity between the accelerometer and force plate data were examined. [Results] The intraclass correlation coefficients indicated a peak vertical acceleration of 0.88, time between initial contact and peak vertical acceleration of 0.96, and knee joint mediolateral sway of 0.62. The magnitude and timing of the peak values between both measurement instruments showed high validity. [Conclusion] The measurement method using a motion sensor for the evaluation of the impact force and knee joint sway during landing has a moderate to high reliability and criterion-related validity. A motion sensor measurement might be a useful and easy method for evaluating landing impact force and knee joint stability.

Effect of toe contact condition during forward stepping on the ground reaction forces during turning movement.

[Purpose] This study aimed to classify the plantar contact condition during forward stepping by focusing on the medial and lateral toes and to elucidate the relationship between the classification and turning movement. [Participants and Methods] The participants were 38 females. The plantar contact condition during forward stepping was evaluated for all participants, and the results were used for the group classification. In all the classified participants, the ground reaction force (GRF) during turning movement was measured. [Results] At sidestep (SS) and cross-step (CS), the peak medial-lateral GRF was significantly smaller in the medial floating toe (MFT) group than in the contact toe (CT) group. At SS, the peak times of the medial-lateral GRF in the MFT and lateral floating toe groups were significantly lesser than those in the CT group. At CS, the push-off peak time of the anterior-posterior GRF was significantly lesser in the MFT group than in the CT group. [Conclusion] The results of this study confirmed that each group classified according to the floating toe classification during forward stepping has different characteristics with respect to the ground reaction force during the turning movement, particularly the medial-lateral ground reaction force and its peak time.

Relationship between foot alignment and floating toes classified in static and dynamic conditions in females.

[Purpose] This study aimed to investigate the plantar contact condition in females and to clarify the relationship between the foot alignment and floating toes classified in static and dynamic conditions. [Participants and Methods] The participants were 122 females. We evaluated the plantar contact condition, calculated the floating toe score, and classified the floating toes of the participants. The floating toes were classified into improvable and unimprovable floating toe groups based on the floating toe score measured in dynamic conditions. Furthermore, foot alignment was evaluated in 35 participants randomized and extracted from the contact toe and the improvable and unimprovable floating toe groups. [Results] The Arch Height Index in the unimprovable floating toe group was significantly smaller than that in the improvable floating toe group. The digitus minimus varus angle in the unimprovable floating toe group was significantly larger than that in the improvable floating toe group. No significant differences were observed in other items. [Conclusion] This study revealed that the foot alignment between the improvable and unimprovable floating toe groups has different features. However, no significant difference was found in the foot alignment between the contact and floating toe groups. Henceforth, it is necessary to evaluate and classify floating toes considering the functional aspects.

Three-dimensional kinematic analysis of glenohumeral, scapular, and thoracic angles at maximum shoulder external rotation associated with baseball shadow pitching: comparison with normal pitching.

[Purpose] The glenohumeral, scapular, and thoracic angles at maximum shoulder external rotation during shadow pitching were evaluated and compared with those observed during normal pitching. [Participants and Methods] Our study included 13 healthy males with experience in pitcher activity. All participants performed both, shadow pitching using a towel and normal pitching using a ball. The external rotation of the glenohumeral joint, scapular posterior tilting, and thoracic extension angles in the cocking phase were measured using a 3-dimensional motion analysis system. The ratios of the glenohumeral external rotation angle to the scapular posterior tilting and/or thoracic extension angle were calculated to evaluate the contribution of the scapulothoracic joint at maximum external rotation during throwing/pitching activity. [Results] The glenohumeral external rotation angle at maximum shoulder external rotation was significantly smaller during shadow pitching than during normal pitching. The ratio of the glenohumeral external rotation angle to the scapular posterior tilting and/or thoracic extension angle showed no statistically significant difference. [Conclusion] We conclude that shadow pitching can reduce the external rotation motion of the glenohumeral joint compared to that during normal pitching and might be a useful pre-throwing program beneficial in the rehabilitation of those presenting with throwing injuries.

Strength and muscle activity of shoulder external rotation of subjects with and without scapular dyskinesis.

[Purpose] This study aimed to clarify the relationship between scapular dyskinesis and shoulder external rotation strength and muscle activity. [Subjects and Methods] Both shoulders of 20 healthy males were evaluated. They were classified into 19 normal, 8 subtly abnormal, and 13 obviously abnormal shoulders using the scapular dyskinesis test. Subtly abnormal shoulders were subsequently excluded from the analysis. Shoulder external rotation strength and muscle activity (infraspinatus, serratus anterior, upper, middle, and lower trapezius) were measured in 2 positions using a handheld dynamometer and surface electromyography while sitting in a chair with shoulder 0° abduction and flexion (1st position), and while lying prone on the elbows with the shoulders elevated in the zero position (zero position). The strength ratio was calculated to quantify the change in strength between the positions (zero position / 1st position). [Results] In the obviously abnormal shoulder group, the strength in the 1st position was significantly stronger, the strength ratio was significantly smaller, and the serratus anterior in the zero position showed significantly lower activity than the normal shoulder group. [Conclusion] In shoulder external rotation in the zero position, in obviously abnormal shoulders, the serratus anterior is poorly recruited, weakening the shoulder external rotation strength.

Electromyographic analysis of the infraspinatus and scapular stabilizing muscles during isometric shoulder external rotation at various shoulder elevation angles.

[Purpose] This study aimed to clarify activation of the infraspinatus and scapular stabilizing muscles during shoulder external rotation at various shoulder elevation angles. [Subjects] Twenty subjects participated in this study and all measurements were performed on the right shoulder. [Methods] Isometric shoulder external rotation strength and surface electromyographic data were measured with the shoulder at 0°, 45°, 90°, and 135° elevation in the scapular plane. The electromyographic data were collected from the infraspinatus, upper trapezius, middle trapezius, lower trapezius, and serratus anterior muscles. These measurements were compared across the various shoulder elevation angles. [Results] The strength measurements did not differ significantly by angulation. The infraspinatus activity was 92%, 75%, 68%, and 57% of the maximum voluntary contraction, which significantly decreased as shoulder elevation increased. The serratus anterior activity was 24%, 48%, 53%, and 62% of the maximum voluntary contraction, which significantly increased as shoulder elevation increased. [Conclusion] Shoulder external rotation torque was maintained regardless of shoulder elevation angle. The shoulder approximated to the zero position as the shoulder elevation increased so that infraspinatus activity decreased and the scapular posterior tilting by the serratus anterior might generate shoulder external rotation torque.

Relationship between spinal range of motion and trunk muscle activity during trunk rotation.

[Purpose] The aim of this study was to clarify the relationship between spinal range of motion and trunk muscle activity during trunk rotation using a three-dimensional motion analysis system and surface electromyography. [Subjects and Methods] The subjects comprised 11 healthy men. A three-dimensional motion analysis system measured the trunk rotational angle of 4 segments of the thoracic vertebrae and 2 segments of the lumbar vertebrae. Surface electromyography measured the activities of the unilateral latissimus dorsi, lumbar multifidus, rectus abdominis, external oblique, internal oblique, and transversus abdominis muscles. [Results] During ipsilateral rotation at thoracic vertebral levels, the muscle activity of the latissimus dorsi and external oblique was significantly increased compared with the activity in the 0-10% range of trunk rotation. During early ipsilateral rotation at lumbar vertebral levels, the muscle activity of the internal oblique and transversus abdominis was significantly increased compared with that in the 0-10% range of trunk rotation. During contralateral rotation at both thoracic and lumbar vertebral levels, the muscle activity of the external oblique was significantly increased compared with that in the 0-10% range of trunk rotation. [Conclusion] This study indicates that it is important to consider vertebral segments and spinal range of motion during trunk rotation.

Effect of 12-month rehabilitation with low loading program on chronic respiratory disease.

[Purpose] The purpose of this study was to examine the effect of 12-month rehabilitation with low loading program on chronic respiratory disease. [Subjects and Methods] Twelve patients with chronic respiratory disease participated in this study, in which the effect of long-term rehabilitation for 12 months was assessed. Nine patients had chronic obstructive pulmonary disease, two had asthma, and one had interstitial pneumonia. In all patients, symptoms, lower-extremity strength, walking distance, activities of daily living, and quality of life were investigated to examine the effect of respiratory rehabilitation. [Results] After 12 months, the isometric knee extension strength and weight-bearing index both showed a significant increase. [Conclusion] The findings of this study suggested that improvement in lower-limb muscle strength can be achieved through long-term intervention, and indicated the validity of repetitive standing and walking exercises.

Effect of various hand position widths on scapular stabilizing muscles during the push-up plus exercise in healthy people.

[Purpose] The purpose of this study was to determine the effect of various hand position widths during the push-up plus (PUP) exercise on the activity of the scapular stabilizing muscles and other upper-extremity muscles involved in the exercise. [Subjects and Methods] Nine healthy men participated in our study. The PUP exercise was performed on a stable surface in seven different hand positions, namely shoulder width (SW), and narrower SW (NSW) and wider SW (WSW) at 10%, 20%, and 30%. Surface electromyography was used to measure the muscle activities and muscle ratio of the upper trapezius (UT), middle trapezius, lower trapezius (LT), serratus anterior (SA), pectoralis major, deltoid anterior, latissimus dorsi (LD), and triceps muscles. [Results] The SA and LD muscle activities significantly decreased in the 30% NSW and 20% WSW hand positions, respectively. The UT/LT muscle ratio significantly increased in the 30% WSW hand position. [Conclusion] The results of this study suggest that during the PUP exercise, the SW hand position should be used. In the 30% NSW hand position, the SA muscle activity decreased, and the UT/ LT ratio increased in the 30% WSW hand position.

Relationship between joint motion and acceleration during single-leg standing in healthy male adults.

[Purpose] The purpose of this study was to clarify the relationship between acceleration and joint movement by synchronizing accelerometers and a three-dimensional motion analysis system, and to show the utility of an accelerometer as a postural control assessment tool. [Subjects and Methods] Head, lumbar, shank accelerations and various joint angles during single-leg standing were measured of 20 healthy males. Root mean squares of acceleration and joint angle were calculated. Fast Fourier transform analysis was performed for head, lumbar, and shank accelerations, and the median frequencies were calculated. Then, principal component analysis was performed for the median frequency of each acceleration. Stepwise multiple regression analysis was also used to examine the relationship between joint angle and acceleration. [Results] The score of the first principal component was highest for shank acceleration, while that of the second principal component was highest for lumbar and head accelerations. In multiple regression analysis, hip flexion/extension and adduction/abduction were identified as variables associated with head acceleration. [Conclusion] We were able to confirm the aggregation of acceleration into two components, which we interpreted as postural control strategies using primarily the ankle and hip joints. Furthermore, though multiple regression analysis, we were able to clarify the joint movement indicated by acceleration of each segment.

Relationship between Lower Extremity Tightness and Star Excursion Balance Test Performance in Junior High School Baseball Players.

[Purpose] The purpose of this study was to examine the relationship between lower extremity tightness and lower extremity balance, measured by the Star Excursion Balance Test (SEBT), in junior high school baseball players. [Subjects] Thirty-three male students belonging to baseball clubs in 2 junior high schools participated in this study. [Methods] For the SEBT, we chose to examine the anterior (ANT), posterior (POS), lateral (LAT), and medial (MED) directions. Regarding muscle tightness measurement, the angle of each joint of the bilateral iliopsoas, quadriceps, hamstring, gastrocnemius, hip internal rotator, and hip external rotator was measured. [Results] The ANT direction of the SEBT was significantly negatively correlated with gastrocnemius tightness. The MED direction of the SEBT was significantly positively correlated with hip internal rotator tightness and hamstrings tightness and significantly negatively correlated with gastrocnemius tightness. The LAT direction of the SEBT was significantly negatively correlated with iliopsoas tightness and gastrocnemius tightness. [Conclusion] Since the rate of upper extremity injury is high in these subjects and this could be due to tightness and instability of the lower extremity from a kinetic viewpoint, the SEBT could be used as a standard evaluation test when examining upper extremity injuries in young baseball players.