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Background: Trunk rotation during pitching correlates with pitching velocity and load on the joints of the upper limb. Trunk rotation is often focusing on during teaching the pitching motion. Athletes who exhibit early trunk rotation during pitching often have low thoracic spine rotational range of motion. The purpose of this study was to investigate the relationship between the range of thoracic spine rotation measured using the lumbar locked rotation test (LLR-t), hip-shoulder separation (H/S) and thoracic rotation angle at stride foot contact (SFC), and ball velocity. Study design: Descriptive laboratory study. Methods: Fifteen healthy male high school students belonging to a baseball club were recruited for participation. The throwing side and non-throwing side LLR-t was performed using an inclinometer. Hip-shoulder separation and thoracic rotation angle during SFC were measured using a pitching motion analysis application: Pitch AI. In addition, a tracking device specifically designed for pitching：Pitching2.0 was employed to measure ball velocity. Correlations between LLR angle, H/S, trunk rotation angles at SFC, and ball velocity were examined using Pearson's correlation coefficient. Result: There was a positive correlation（r=0.52，p=0.047） between the LLRt angle and H/S. Additionally, there was a negative correlation（r=-0.62, p =0.01） between the LLRt angle on the throwing side and thoracic rotation angle. There was a positive correlation(r=0.54, p=0.04) between ball velocity and H/S and a negative correlation(r=-0.56, p=0.03) between ball velocity and thoracic rotation angle during SFC. Conclusion: The LLR-t measures thoracic rotation angle with the pelvis-lumbar spine fixed. The results indicated that throwing side LLR was related to the thoracic angle during SFC and hip-shoulder separation. Level of evidence: 3 [ABSTRACT FROM AUTHOR]

Background: Deltoid muscle detachment and atrophy have been reported to occur after shoulder surgery. Purpose: To investigate the 2-year changes in deltoid muscle structure and function after arthroscopic rotator cuff repair (ARCR) using magnetic resonance imaging (MRI) and electrophysical examination. Study Design: Case series; Level of evidence, 4. Methods: A total of 72 patients (72 shoulders) who underwent ARCR between 2015 and 2020 were enrolled. Whole deltoid muscle volume and regional (anterior, lateral, and posterior) muscle thicknesses were determined on T2-weighted MRI scans of both shoulders taken preoperatively and at 1, 3, 6, 12, and 24 months postoperatively, and their correlations with compound muscle action potentials (CMAPs), shoulder abduction muscle strength, and Constant scores were investigated. Comparison between groups was performed using paired or Student t tests, and the relationship between deltoid muscle volume and various factors was determined using Pearson correlation analysis. Results: The volume of the deltoid muscle on the affected side decreased from 44,369 ± 12,371 mm3 preoperatively to 38,139 ± 10,615 mm3 at 1 month postoperatively (P <.05), representing a 14% decrease. The deltoid muscle volume of the contralateral side also significantly decreased during the same time frame, from 43,278 ± 12,248 to 40,273 ± 11,464 mm3 (P <.05), representing a 7% decrease at 1 month postoperatively. Subsequently, the deltoid muscle volume on both sides recovered to preoperative levels at 12 months and was maintained at 24 months. Only the thickness of the anterior part of the deltoid was markedly decreased, from 13.9 ± 3.7 mm preoperatively to 12.0 ± 3.2 mm at 1 month postoperatively (P <.05), representing a 14% reduction. The CMAP amplitude showed a significant decrease at 1 month postoperatively; however, no significant difference was observed after 12 months when compared with the preoperative values or the values on the contralateral side. Positive correlations were found between deltoid muscle volume and CMAP amplitude at 24 months as well as between deltoid muscle volume and shoulder abduction muscle strength (R 2 = 0.698; P <.05) and Constant score (R 2 = 0.133; P <.05). Conclusion: Our study demonstrated that the early structural and functional decline of the deltoid muscle after ARCR was fully recovered within 1 year, confirming that this procedure does not negatively affect the deltoid muscle. [ABSTRACT FROM AUTHOR]

Context: The range of shoulder rotation is associated with shoulder pain in young male and female swimmers. However, the association between shoulder pain and shoulder complex mobility of the scapulothoracic and acromioclavicular joints has not yet been examined. Moreover, shoulder pain occurs more frequently in females than in males, but only a few studies have examined the relationship between shoulder pain and sex as a risk factor. This study aims to determine the association between shoulder complex mobility and shoulder pain in young male and female swimmers. Design: Prospective cohort design. Methods: The participants were competitive swimmers (n = 76; 37 males and 39 females) with a mean age of 14 years in Japan. The shoulder rotation width, which was the index of shoulder complex mobility, shoulder internal and external rotation range, and middle finger distance of the back-scratch test were measured. An examiner regularly visited the swimming clubs to evaluate the development of shoulder pain and swimming distance. Logistic regression analysis was used to determine the physical characteristics related to the overall development of shoulder pain in both female and male swimmers. The cutoff value was calculated using receiver operating characteristic curves. Results: Sixteen participants, composed of 8 males and 8 females, developed shoulder pain. The overall swimming distance of the male (odds ratio [OR]: 1.0007, P = .01) and female (OR: 1.0018, P = .02) swimmers and the shoulder rotation width of the male (OR: 1.0952, P = .04) and female (OR: 0.888, P = .03) swimmers were identified as risk factors for shoulder pain. The cutoff value for swimming distance was 6000 m. Shoulder rotation width was more than 88 cm in males and <54 cm in females. Conclusions: Hypomobility and hypermobility of the shoulder complex were identified as risk factors for shoulder pain in male and female swimmers, respectively. [ABSTRACT FROM AUTHOR]

Rehabilitation devices for passive exercise have been actively researched and developed in accordance with Japan's aging society. A previous study proposed and tested an extension-type flexible pneumatic actuator (EFPA) with reinforced stiffness that could achieve passive exercise in patients. In addition, a rehabilitation device for shoulder joints with an embedded controller and small valves was proposed and tested. Joints such as the shoulder and scapula were subjected to passive exercise utilizing the tested device. However, it is difficult for patients with contractions to perform the same exercise because the reinforced EFPA can buckle. Here, to realize an EFPA with a higher stiffness, a flexible actuator in the shape of a hexagonal pyramid is proposed and tested. The hexagonal pyramid shape of a flexible actuator has a high stiffness in the direction of motion and flexibility in other directions; hereafter, this characteristic is called anisotropic stiffness. The characteristics of the hexagonal pyramid shape of the EFPA are described and compared with those of a previously reinforced EFPA. An analytical model was proposed to predict and design the shape of the hexagonal pyramid EFPA. The validity of the model is also described. [ABSTRACT FROM AUTHOR]

Background: Whether the extent of glenoid bone loss (GBL) affects clinical outcome after coracoid process transfer (CPT) is still unclear. Purpose: To evaluate postoperative outcomes after CPT combined with open Bankart repair in young rugby players in terms of the extent of GBL and between the Bristow and Latarjet techniques. Study Design: Cohort study; Level of evidence, 3. Methods: The authors investigated 101 shoulders in 91 competitive rugby players who underwent CPT combined with open Bankart repair by the Bristow (group B; 66 shoulders) or Latarjet (group L; 35 shoulders) procedure between 2007 and 2017. The extent of GBL was calculated from the en face view of the glenoid on preoperative 3-dimensional computed tomography scans and was used to categorize shoulders into 4 grades (grade 0, 0%; grade 1, >0% and ≤10%; grade 2, >10% and ≤20%; grade 3, >20%). At the minimum 2-year follow-up, the authors analyzed the relationship between GBL or GBL grade and postoperative outcome scores (American Shoulder and Elbow Surgeons score, Rowe score, Western Ontario Shoulder Instability Index, and patient satisfaction), return-to-play (RTP) times, graft failure (insufficient union or translocation), and recurrence. Results: The mean GBL in all shoulders was 10.9% ± 9.2% and was not significantly different between the 2 groups. There were no significant correlations between GBL and any outcome measure in either group. The mean RTP time was significantly shorter in group L versus group B (4.8 ± 1.1 vs 5.8 ± 1.8 months, respectively; P =.002), but it was not associated with GBL. In group B, the rate of graft failure was not significantly higher in shoulders with grade 0 or 1 GBL versus grade 2 or 3 GBL (8 [25.0%] vs 4 [11.8%], respectively; P =.21). In group B, graft failure was confirmed in 12 shoulders (18.2%), compared with 1 shoulder (2.9%) in group L. Postoperative recurrence occurred in significantly fewer shoulders in group B than in group L (2 [3.0%] vs 5 [14.3%], respectively; P =.047). Conclusion: The extent of GBL did not affect outcome scores after CPT, regardless of operative procedure. [ABSTRACT FROM AUTHOR]

BACKGROUND: Manual operations of the hydraulic jack device can become ergonomic stressors for the musculoskeletal system because of the required operational forces, muscle activities, or working postures. However, the usability of the hydraulic jack has not been fully explored for non-professional personnel. OBJECTIVES: To evaluate the musculoskeletal loads during manual operations of a hydraulic jack based on the ergonomic postural analysis and electromyography METHODS: Nine men operated the lever of a hydraulic jack with three positions: parallel to and near (P-N), parallel to and far from (P-F), and orthogonal to the jack lever (O). Postural loads were evaluated by Loading on the Upper Body Assessment (LUBA), an ergonomic observational method, and were classified into action categories. The surface electromyogram of eight muscles and the subjective sense of burden were also measured. RESULTS: The initial force for lever pushing reached 40–80 N and exceeded the recommended forces for the unusual postures. The overall assessment of LUBA showed that 31% of working postures observed in O position require immediate consideration and corrective action and the maximum holding time estimated was < 1 minute. The postural load increased due to the shoulder joint abduction in the P-F and O positions and due to the trunk rotation in O position. CONCLUSIONS: The results suggest that operating the hydraulic jack cause considerable postural loads and manual forces insufficient for several minutes of manual task. Therefore, improving working methods and tool designs are needed to improve usability and decrease the risk of musculoskeletal disorders during jack operations. [ABSTRACT FROM AUTHOR]

Background: Traumatic anterior shoulder instability in collision sports athletes often involves osseous glenoid lesions, which make surgical treatment challenging. High redislocation rates have been seen in collision sports athletes treated using arthroscopic Bankart repair. Purpose: To investigate the effectiveness of a combined arthroscopic Bankart repair and open Bristow procedure for the treatment of traumatic anterior shoulder instability in collision sports athletes, with a focus on osseous glenoid lesions. Study Design: Case series; Level of evidence, 4. Methods: We reviewed 149 shoulders in 141 competitive collision sports athletes (mean ± standard deviation age, 20.1 ± 4.1 years; 8 bilateral cases) who underwent a combined arthroscopic Bankart repair and open Bristow procedure with minimum 2 years of follow-up. Osseous Bankart lesions were arthroscopically reduced and fixed using a coracoid graft. Results: Clinical outcomes as indicated by mean Rowe score improved significantly from 50.0 preoperatively to 98.9 postoperatively (P <.001) at a median follow-up of 3.4 years (range, 2.5-7 years). There were 2 recurrent dislocations (1.3%), both of which had nonunion of the transferred coracoid. Osseous Bankart lesions were observed in 85 shoulders, and osseous glenoid lesions ≥10% of the diameter of the nonoperative side were found in 58 shoulders, including 24 off-track cases. Clinical outcomes were not significantly different between patients with a glenoid defect ≥10% and <10%. Nonunion of the transferred coracoid was observed in 16 shoulders (10.7%), which had inferior Rowe scores; however, we could not define any risk factors for nonunion, including patient characteristics or bone morphology. Postoperative computed tomography performed in 29 patients >1 year after surgery showed successful repair of the osseous glenoid lesions, with a restored glenoid articular surface in all cases. Significant pre- to postoperative increases were seen in glenoid diameter (mean, 13.1% [95% CI, 9.9%-16.3%]; P <.001) and area (mean, 10.6% [95% CI, 8.5%-12.7%]; P <.001). Conclusion: A combined arthroscopic Bankart repair and open Bristow procedure improved bone morphology and was a reliable surgical method for treating collision sports athletes with traumatic anterior shoulder instability involving osseous glenoid lesions. [ABSTRACT FROM AUTHOR]

Background: To determine normative values for the QuickDASH questionnaire in the elderly Japanese population and their associated factors. Methods: Three-hundred and eighty-one residents between 50 and 89 years of age were randomly selected from residents of a town in Japan. All participants completed a QuickDASH questionnaire. A multivariate analysis was performed to identify associated factors. Results: Males and females aged 70–79 and 80–89 showed significantly higher QuickDASH scores than the 50–59 age groups. Females aged 50 to 59 showed significantly higher QuickDASH scores than males aged 50–59. Motion pain or tenderness at the shoulder and side pinch strength showed a significant effect on QuickDASH scores. Conclusions: The mean QuickDASH score was 5.7. As an associated factor for the QuickDASH, aging, female, and shoulder disorders were confirmed. [ABSTRACT FROM AUTHOR]

Background: Shoulder and elbow examinations for pitchers have been performed in Japan's National High School Baseball Invitational Tournaments (NHSBITs) and National High School Baseball Championships (NHSBCs) since 1993. However, for years the results have not been analyzed. The purpose of this study was to evaluate changes in the condition of shoulders and/or elbows of pitchers from 1993 to 2016.Materials and Methods: Pitchers in NHSBITs and NHSBCs, 1994-2016, were examined together with those who received a trial examination (Trial) in the NHSBC 1993. Shoulder and elbow symptoms were comprehensively graded into five categories; none, mild, moderate, severe and dysfunction. Standard plain radiographs of the shoulder and elbow were obtained. Average Annual Percent Changes (AAPCs) in the percentages of pitchers with symptoms and positive radiographic findings were analyzed.Results: The percentages of pitchers with moderate or worse symptoms in the shoulder or elbow were 14.6% and 13.8%, respectively, in the Trial, 1.1% and 1.1% in NHSBITs and 1.3% and 2.0% in NHSBCs. The AAPC of pitchers with a symptomatic shoulder in NHSBITs was reduced over the study period, at -3.36% (P < 0.05), but that in NHSBCs was unchanged at -1.01%. The AAPCs of pitchers with a symptomatic elbow in NHSBITs and in NHSBCs decreased, at -3.13% and -3.33%, respectively (P < 0.05), while that of pitchers with residual apophyseal fragmentation at the ulnar collateral ligament insertion increased at +2.79% (P < 0.05). The decreased percentages of symptomatic pitchers suggest that joint condition is well controlled in high school days; however, the increased frequency of radiographic findings suggests the necessity of protection against overuse in younger players.Conclusions: The percentages of pitchers with symptomatic shoulders and elbows in NHSBITs and those with symptomatic elbows in NHSBCs have decreased over the 23 years. However, the increased frequency of residual medial humeral epicondyle apophyseopathy should be noted. [ABSTRACT FROM AUTHOR]

Clonal complex 398 methicillin-resistant Staphylococcus aureus (MRSA) is a typical lineage of livestock-associated MRSA. We report a case of intractable arthritis of the shoulder joint caused by a multidrug-resistant Panton-Valentine leukocidin-positive livestock-associated MRSA clonal complex 398 sequence type 1232 clone in a patient in Japan who had no animal contact. [ABSTRACT FROM AUTHOR]

Background: During pitching, an overloaded joint reaction force exerted on the shoulder and excessive shoulder horizontal abduction at ball release are considered risk factors causing anterior shoulder pain for young baseball pitchers. Hypothesis/Purpose: The first aim was to examine the relationship between shoulder horizontal abduction position and force on the shoulder at ball release. The second was to identify the relative rotational position of the shoulder and the range of shoulder motion at ball release that minimize force on the shoulder. It was hypothesized that the amount of force on the shoulder would be exacerbated by excessive shoulder horizontal abduction. Study Design: Descriptive laboratory study. Methods: Participants were 183 adolescent baseball pitchers (mean ± SD age, 15.5 ± 1.2 years) without shoulder/elbow problems. Each pitcher threw 5 fastballs to a catcher behind a home plate. The kinematics and kinetics of the throwing shoulder during fastball pitching were calculated with 3-dimensional measurements from 36 reflective markers. In data analysis, the correlations were calculated between the relative rotational positions of the shoulder (abduction, horizontal adduction-abduction) and the forces on the shoulder (anterior-posterior, proximal, and superior-inferior) at ball release. Subsequently, the specific rotational position and range of motion of the shoulder at ball release that minimized forces on the shoulder were determined. Results: Statistically significant correlations were identified between the magnitude of superior-inferior force on the shoulder and shoulder abduction position (R2 = 0.44, P < .001) as well as between the magnitude of anterior-posterior force on the shoulder and shoulder horizontal adduction-abduction position (R2 = 0.72, P < .001). Minimal anterior-posterior and superior-inferior forces were obtained with a combination of 80.6° of shoulder abduction and 10.7° of shoulder horizontal adduction. Any deviation >5° from this position significantly increased the anterior-posterior and superior-inferior forces on the shoulder. Conclusion: Increasing shoulder horizontal abduction position significantly increased the magnitude of anterior force on the shoulder at ball release. The combination of 80.6° of shoulder abduction and 10.7° of horizontal shoulder adduction minimized the shear forces on the shoulder at this point. Clinical Relevance: The present data can be useful for screening pitching technique to prevent shoulder pain and injury with motion capture assessment. [ABSTRACT FROM AUTHOR]

Background: Conventional tests of shoulder laxity have been shown to have poor reliability due to the difficulty in palpating the subtle movements of the shoulder joint beneath the musculature. Modified drawer test that is performed while the soft tissues surrounding the shoulder are loosened has been proposed to facilitate glenohumeral joint movement and improve reliability. We hypothesised that the modified drawer test would have an improved intra- and inter-observer reproducibility in comparison to the drawer and load and shift tests. Correlation of shoulder laxity measured by these tests with generalized joint laxity was also assessed.Methods: Forty healthy volunteers underwent bilateral shoulder examination in the clinic using the three tests for anterior and posterior laxity assessment by a consultant shoulder surgeon and a resident. The examination was repeated three months later by the same examiners in the same cohort. Intra- and inter- observer reproducibility was calculated using Kappa values. The correlation of shoulder with generalized joint laxity was also investigated.Results: The modified drawer test showed significantly improved intra-observer reproducibility compared to the drawer test, but not to the load and shift (κ = 0.173, -0.042, and 0.009, respectively). There were no significant differences in the inter-observer reproducibility between the three tests (κ = 0.054, 0.055, and 0.056, respectively). Moderate correlation was noted between shoulder and generalized joint laxity when modified drawer test was used (r = 0.417).Conclusions: The modified drawer test improves intra- but not inter- observer reproducibility compared to the drawer test. Shoulder laxity assessed by the modified test correlated to generalized joint laxity. The modified drawer test has an improved reproducibility and correlation to generalized joint laxity over the conventional tests. [ABSTRACT FROM AUTHOR]

Many coaches often instruct swimmers to keep the elbow in a high position (high elbow position) during early phase of the underwater stroke motion (pull phase) in front crawl, however, the high elbow position has never been quantitatively evaluated. The aims of this study were (1) to quantitatively evaluate the “high elbow” position, (2) to clarify the relationship between the high elbow position and required upper limb configuration and (3) to examine the efficacy of high elbow position on the resultant swimming velocity. Sixteen highly skilled and 6 novice male swimmers performed 25 m front crawl with maximal effort and their 3-dimensional arm stroke motion was captured at 60 Hz. An attempt was made to develop a new index to evaluate the high elbow position (Ihe: high elbow index) using 3-dimensional coordinates of the shoulder, elbow and wrist joints. Iheof skilled swimmers moderately correlated with the average shoulder internal rotation angle (r = −0.652,P < 0.01) and swimming velocity (r = −0.683,P < 0.01) during the pull phase. These results indicate that Iheis a useful index for evaluating high elbow arm stroke technique during the pull phase in front crawl. [ABSTRACT FROM AUTHOR]

Background: Conservative management is often the first-choice treatment for baseball players with disabled throwing shoulder (DTS). Considering the high popularity of baseball in Japan, we suspected that there might be some evidence regarding this topic in the Japanese-language literature. Objective: This study aimed to systematically review Japanese-language primary studies investigating the effectiveness of conservative management for DTS in baseball. Methods: Eight databases were systematically searched from inception to 7 April 2016. Data on authors, publication years, sample characteristics, types of interventions, outcome measures and results were extracted. Data were synthesised qualitatively. Results: Seven studies with low evidence level and low-to-moderate study quality were included. Interventions examined in the included studies were downward throwing, combined physiotherapy interventions and joint distension. Forming correction, stretching for posterior shoulder muscles and strengthening exercises to improve scapular/trunk stability were commonly used in combined physiotherapy interventions. Downward throwing and combined physiotherapy interventions corresponded with expert opinions described in the English-language literature. Due to the lack of studies with high level of evidence, however, it was difficult to determine the genuine effects of these interventions. Conclusion: Our systematic review found limited evidence about the effectiveness of any conservative management for baseball players with DTS. Although downward throwing and combined physiotherapy interventions might be appropriate management in some cases, further studies of higher level of evidence and greater methodological rigour are required. [ABSTRACT FROM AUTHOR]

Objectives: Massage therapy is one of the most commonly used complementary therapies for patients with Parkinson's disease (PD). The aim of this preliminary study was to evaluate the effects of traditional Japanese massage therapy on various symptoms of patients with PD. Design: The study design was a case series study. Setting: The study was conducted at the Center for Integrative Medicine, Tsukuba University of Technology, Japan. Subjects: The subjects were 10 patients with idiopathic PD (mean age, 69.6±7.7 years; range, 55-85 years) who presented for consultation with a neurologist between February and April 2009 and who desired massage therapy in conjunction with standard pharmaceutical treatment. Intervention: The intervention comprised a 30-minute session of traditional Japanese massage in conjunction with standard conventional medication. Outcome measures: The outcome measures were as follows: Gait speed in the 20-m walk test (10-m walk and return) for gait disturbance, angular range of shoulder joint motion for frozen shoulder, and a visual analogue scale (VAS) for assessing the severity of each of various symptoms (hypophonia, shoulder stiffness, muscle pain, heaviness or lassitude of a body part, and fatigue), as determined before and after the massage session. Results: (1) Patients with gait disturbance showed improved gait speed, (2) those with frozen shoulder showed improved range of motion of the shoulder joint, and (3) VAS scores for assessing the severity of other subjective symptoms were improved. Conclusions: These results suggest that traditional Japanese massage therapy used in combination with medication is effective for alleviating various symptoms in patients with PD and may contribute to enhancing their health-related quality of life. Larger studies with a control group are required to verify these findings. [ABSTRACT FROM AUTHOR]