Nobuyuki Itaya

Association Between Sleep Disturbance and New-onset Subjective Shoulder Pain in Survivors of the Great East Japan Earthquake: A Prospective Cohort Study in Miyagi Prefecture

The Great East Japan Earthquake (GEJE) and Tsunami devastated the northeastern coast of Japan on March 11, 2011. This study attempted to determine whether socio-psychological factors such as sleep disturbance and psychological distress influenced new-onset subjective shoulder pain in survivors, during the post disaster phase of the GEJE. From November 2012 to February 2013 (2 years after the GEJE) and November 2014 to January 2015 (4 years after the GEJE), survivors (18 years old or over) answered self-reported questionnaires. In total, 1,454 survivors responded to the questionnaires and were thus included in this study. New-onset subjective shoulder pain was defined as shoulder pain by encircled response absent at 2 years, and present at 4 years after the GEJE. Two years after the GEJE, ≥ 10/24 points on the Kessler Psychological Distress Scale-6, and ≥ 6/24 points on the Athens Insomnia Scale defined the presence of psychological distress and sleep disturbance, respectively. Multiple logistic regression analysis was used to estimate the odds ratio (OR) and 95% confidence interval (CI) of the association between new-onset subjective shoulder pain, and psychological distress or sleep disturbance. Amongst participants, 7.2% (105/1,454) reported new-onset subjective shoulder pain. Sleep disturbance was significantly associated with new-onset subjective shoulder pain (OR = 1.92, 95% CI = 1.24-2.98, P = 0.004); however, psychological distress was not (OR = 0.78, 95% CI = 0.42-1.42, P = 0.41). In conclusion, this is the first study indicating an association between sleep disturbance and new-onset subjective shoulder pain amongst the survivors of the GEJE.

Decreased elastic fibers and increased proteoglycans in the ligamentum flavum of patients with lumbar spinal canal stenosis.

Elastic fibers and proteoglycans are major components of the extracellular matrix and their changes have been reported in some pathological conditions. Further, recent studies have indicated that some glycosaminoglycans and proteoglycans inhibit elastic fiber assembly. The purpose of this study was to investigate changes of the elastic fibers and proteoglycans in the ligamentum flavum and analyze their relationships to thickening of the ligamentum flavum from lumbar spinal canal stenosis (LSCS). Ligamentum flavum samples were collected from 20 patients with LSCS (thickened flavum group) and 10 patients with lumbar disc herniation (non‐thickened flavum group) as a control. Elastica–Masson staining and alcian blue staining were used to compare the relationship between the changes in the elastic fibers and proteoglycans. Gene and protein expressions of the elastic fibers and proteoglycans were analyzed by quantitative reverse transcription polymerase chain reaction and immunohistochemistry. Histological changes indicated that proteoglycans mainly increased on the dorsal side of the ligamentum flavum in accordance with the decreased elastic fibers in the thickened flavum group. The gene and protein expressions of fibrillin‐2 and DANCE were significantly lower and decorin, lumican, osteoglycin, and versican were significantly higher in the thickened flavum group. Our study shows that elastic fibers decrease and proteoglycans increase in the thickened ligamentum flavum. Decreased gene expression of elastogenesis and disrupted elastic fiber assembly caused by increased proteoglycans may lead to a loss of elasticity in the thickened ligamentum flavum. Decreased elasticity may cause buckling of the tissue, which leads to thickening of the ligamentum flavum.

Coexistence of Trunk or Lower Extremity Pain with Elbow and/or Shoulder Pain among Young Overhead Athletes: A Cross-Sectional Study

Elbow or shoulder injuries are common in overhead sports. Because energy derived from the lower extremity passes through the trunk to the upper extremity in overhead motion, a break in such a kinetic chain could lead to arm injuries. However, there is only limited information about the role of the trunk and lower extremity support in preventing elbow or shoulder injuries. This study aimed to explore the association of trunk and lower extremity pain with elbow/shoulder pain among young overhead athletes. We conducted a cross-sectional study using self-reported questionnaires mailed to young athletes belonging to the Miyagi Amateur Sports Association. The final study population comprised 2,215 young athletes playing baseball (n = 1,422), volleyball (n = 546), softball (n = 14), handball (n = 28), tennis (n = 110), or badminton (n = 95). The median age of the participants was 11 years (range: 6 to 15 years). Multiple logistic regression analysis revealed the higher prevalence of elbow and/or shoulder pain in athletes with back pain (OR = 5.52, 95% CI = 3.51-8.69), hip pain (OR = 6.13, 95% CI = 3.35-11.22), knee pain (OR = 2.28, 95% CI = 1.48-3.51), and foot pain (OR = 3.03, 95% CI = 1.95-4.72), compared with those without pain. We propose that trunk or lower extremity pain is significantly associated with elbow or shoulder pain among young overhead athletes. Assessing for pain in trunk or lower extremity, as well as elbow and/or shoulder pain, may help prevent serious injuries in young overhead athletes.

Excessive game playing is associated with musculoskeletal pain among youth athletes: a cross-sectional study in Miyagi prefecture

ABSTRACT Youth athletes are known to be at high risk of musculoskeletal (MSK) injuries. Children in developed countries are increasingly adopting a sedentary lifestyle. Although some risk factors related to sports activities have been reported, the effect of lifestyle (i.e. screen time behaviour) on MSK pain in youth athletes is not well known. This study aimed to examine the association of game playing and TV viewing with MSK pain among youth athletes. A self-administered questionnaire was mailed to youth athletes belonging to the Miyagi Amateur Sports Association. The final study population included 6,143 youth athletes (male, 71.1%; age range, 6–15 years). Multiple logistic regression analysis was used to examine the association of game playing and TV viewing behaviour with MSK pain. The point prevalence of MSK pain was 25.5%. The longest category of game playing time (≥3 h) was significantly associated with MSK pain as compared with the shortest category (<1 h) (odds ratio, 1.39; 95% confidence interval, 1.12–1.73, p = 0.003). There was no significant association between TV viewing time and MSK pain. These results suggest that game playing time might be an associated factor for MSK pain among youth athletes.

Effects of Low-Intensity Pulsed Ultrasound for Preventing Joint Stiffness in Immobilized Knee Model in Rats

The purpose of this study was to examine the effect of low-intensity pulsed ultrasound (LIPUS) in preventing joint stiffness. Unilateral knee joints were immobilized in two groups of rats (n = 6/period/group). Under general anesthesia, the immobilized knee joints were exposed to LIPUS for 20 min/d, 5 d/wk, using an existing LIPUS device (LIPUS group, 1.5-MHz frequency, 1.0-kHz repetition cycle, 200-µs burst width and 30-mW/cm2 power output) until endpoints (2, 4 or 6 wk). In the control group, general anesthesia alone was administered in the same manner as in the other group. The variables compared between the groups included joint angles; histologic, histomorphometric and immunohistochemical analyses; quantitative reverse transcription polymerase chain reactions; and tissue elasticity. LIPUS had a preventive effect on joint stiffness, resulting in decreased adhesion, fibrosis and inflammation and hypoxic response after joint immobilization.

Involvement of neutrophils and interleukin-18 in nociception in a mouse model of muscle pain:

Muscle pain is a common condition that relates to various pathologies. Muscle overuse induces muscle pain, and neutrophils are key players in pain production. Neutrophils also play a central role in chronic pain by secreting interleukin (IL)-18. The aim of this study was to investigate the involvement of neutrophils and IL-18 in a mouse model of muscle pain. The right hind leg muscles of BALB/c mice were stimulated electrically to induce excessive muscle contraction. The left hind leg muscles were not stimulated. The pressure pain threshold, number of neutrophils, and IL-18 levels were investigated. Furthermore, the effects of the IL-18-binding protein and Brilliant Blue G on pain were investigated. In stimulated muscles, pressure pain thresholds decreased, and neutrophil and IL-18 levels increased compared with that in non-stimulated muscles. The administration of IL-18-binding protein and Brilliant Blue G attenuated hyperalgesia caused by excessive muscle contraction. These results suggest that increased IL-18 secretion from larger numbers of neutrophils elicits mechanical hyperalgesia.

Knee pain is associated with lower back pain in young baseball players: a cross-sectional study

PurposeConsiderable research has focused on shoulder and elbow injuries among baseball players; however, although lumbar spine and knee injuries are commonly experienced, they are less frequently studied. During common motions in baseball, such as throwing, hitting, and running, energy is transferred from the lower extremities through the lower back to the upper body. Lower extremity pain, as well as lower back pain (LBP), can disrupt the kinematic chain, and it is important to understand the association between lower extremity complaints and LBP. The purpose of this study was to elucidate the association between knee pain and LBP among young baseball players.MethodsA cross-sectional study was conducted with young baseball players (aged 6–15 years, n = 1,609) using a self-reported questionnaire. Multivariate logistic regression models were used for analyses. Variables considered in the models were sex, age, body mass index, team levels, number of days of training per week, number of hours in practice per day on weekdays and weekend, frequency of participation in games, practice intensity, and player position.ResultsThe point prevalence of LBP and knee pain was 8.4% and 13.1%, respectively. Knee pain was significantly associated with LBP. Using the absence of knee pain as a reference, the adjusted odds ratio (95% confidence interval) for LBP was 5.83 (3.93–8.65) (p < 0.001) in the presence of knee pain.ConclusionsKnee pain was associated with LBP among young baseball players. Clinicians should pay attention to knee complaints to prevent and treat LBP among young baseball players.Level of evidenceIII.

Comparative proteome analysis of the capsule from patients with frozen shoulder

BACKGROUND The etiology of frozen shoulder (FS) is unclear. Accordingly, this study used a label-free quantitative shotgun proteomic approach to elucidate the pathogenesis of FS based on protein expression levels. METHODS Tissue samples from the rotator interval (RI), middle glenohumeral ligament (MGHL), and anterior-inferior glenohumeral ligament (IGHL) were collected from 12 FSs with severe stiffness and 7 shoulders with a rotator cuff tear (RCT) as controls. Protein mixtures were digested and analyzed by nano-liquid chromatography/electrospray ionization-tandem mass spectrometry. Relative protein expression levels were calculated by the signal intensity of identified peptide ions on mass spectra. Differentially expressed proteins between FS and RCT samples were evaluated by a gene enrichment analysis using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. RESULTS We identified 1594 proteins, 1358 of which were expressed in all 6 tissue groups. We detected more upregulated proteins in the upper (RI and MGHL) FS groups and the lower (IGHL) RCT group than in the comparative groups, respectively. Various proteins with functions in tissue repair, collagen metabolism and fibrillation, cell-cell and cell-matrix adhesion, blood coagulation, and the immune response were expressed more highly in the RI and MGHL FS groups than in the RCT group. Proteins with functions in phagocytosis, glutathione metabolism, retinoid metabolism, and cholesterol metabolism were expressed more highly in the IGHL RCT group than in the FS group. CONCLUSIONS The pathophysiology of FS differs between the upper and lower parts of the joint capsule. Different treatment strategies for FS may be appropriate, depending on the location.

Playing video games for more than 3 hours a day is associated with shoulder and elbow pain in elite young male baseball players

BACKGROUND The effect of lifestyle factors on elbow or shoulder pain in young baseball players remains unclear. This study examined the association of game playing and television viewing with elbow or shoulder pain among elite young baseball players. METHODS Study participants were young baseball players (age, 9-12 years) who participated in the National Junior Sports Clubs Baseball Festival in 2017. The national tournament invited 16 teams (totaling 210 players) selected based on the results of the regional qualifying tournaments. Self-reported questionnaires were mailed to all players before the tournament. Multiple logistic regression analyses were used to assess the association of video game playing and television viewing behavior with elbow or shoulder pain. RESULTS Among the 210 players polled, 200 male players were included in the analysis. The prevalence of elbow or shoulder pain was 30.0%. Playing video games for ≥3 hours/day was significantly associated with elbow or shoulder pain vs. spending <1 hour/day playing video games (odds ratio, 5.59; 95% confidence interval, 1.44-21.64; P = .013). The amount of time spent watching television was not significantly associated with the prevalence of elbow or shoulder pain. CONCLUSIONS Playing video games for ≥3 hours/day was associated with elbow or shoulder pain among elite young male baseball players. These findings highlight the effect of lifestyle on elbow and shoulder pain and should be taken into consideration by players, coaches, parents, and clinicians for the prevention of elbow and shoulder pain.