Kuroiwa, Tomoyuki

Abstract Objective Sleeper stretching (SS) and cross‐body stretching (CS) are common nonsurgical interventions for the management of glenohumeral internal rotation deficit (GIRD) in overhead athletes such as baseball and volleyball players. However, the effectiveness of these stretching interventions in enhancing the range of motion (ROM) of shoulder internal rotation (IR) in overhead athletes with GIRD remains a subject of uncertainty. This systematic review and meta‐analysis aim to critically assess the efficacy of SS and CS in the ROM of the IR among overhead athletes with GIRD, thereby providing evidence‐based recommendations for their use. Literature Survey A comprehensive search of MEDLINE, Embase, and Scopus databases up to November 2024 was conducted to identify randomized controlled trials investigating the influence of SS and CS on the ROM of shoulder IR in overhead athletes with GIRD. Methodology Data including study characteristics and outcomes were extracted. Risk of bias assessment and random‐effects model meta‐analysis were performed. Synthesis Six eligible studies involving 255 athletes with GIRD were included. The meta‐analysis demonstrated statistically significant differences between stretching and control groups in terms of enhancing the ROM of IR (mean difference [MD], 7°; 95% confidence interval [CI], 1°–13°; p = .02) and horizontal adduction (HAD) ([MD], 6°; [CI], 1°–11°; p = .03). Conclusion SS or combination of SS and CS interventions significantly enhanced the ROM of IR compared to the control group in overhead athletes diagnosed with GIRD. Furthermore, the review confirmed that SS alone also markedly enhances the ROM of HAD. These findings highlight the potential benefits of SS and CS in managing GIRD and suggest a need for further research to optimize these interventions for broader application in overhead athletes.

AbstractChordae tendineae, referred to as heart tendinous cords, act as tendons connecting the papillary muscles to the valves in the heart. Their role is analogous to tendons in the musculoskeletal system. Despite being exposed to millions of cyclic tensile stretches over a human's lifetime, chordae tendineae rarely suffer from overuse injuries. On the other hand, musculoskeletal tendinopathy is very common and remains challenging in clinical treatment. The objective of this study was to investigate the mechanism behind the remarkable durability and resistance to overuse injuries of chordae tendineae, as well as to explore their effects on flexor tenocyte biology. The messenger RNA expression profiles of chordae tendineae were analyzed using RNA sequencing and verified by quantitative reverse transcription polymerase chain reaction and immunohistochemistry. Interestingly, we found that periostin (Postn) and fibroblast growth factor 7 (FGF7) were expressed at significantly higher levels in chordae tendineae, compared to flexor tendons. We further treated flexor tenocytes in vitro with periostin and FGF7 to examine their effects on the proliferation, migration, apoptosis, and tendon‐related gene expression of flexor tenocytes. The results displayed enhanced cell proliferation ability at an early stage and an antiapoptotic effect on tenocytes, while treated with periostin and/or FGF7 proteins. Furthermore, there was a trend of promoted tenocyte migration capability. These findings indicated that Postn and FGF7 may represent novel cytokines to target flexor tendon healing. Clinical significance: The preliminary discovery leads to a novel idea for treating tendinopathy in the musculoskeletal system using specific molecules identified from chordae tendineae.

Abstract Purpose This systematic review and meta‐analysis aimed to (1) determine the proportion of patients who underwent anterior shoulder instability surgery and did not return to sports for psychological reasons and (2) estimate differences in psychological readiness scores between patients who did and did not return to sports. Methods The EBSCOhost/SPORTDiscus, PubMed/Medline, Scopus, EMBASE and Cochrane Library databases were searched for relevant studies. The data synthesis included the proportion of patients who did not return to sports for psychological reasons and the mean differences in the psychological readiness of athletes who returned and those who did not return to sports. Non‐binomial data were analysed using the inverse‐variance approach and expressed as the mean difference with 95% confidence intervals. Results The search yielded 700 records, of which 13 (1093 patients) were included. Fourteen psychological factors were identified as potential causes for not returning to sports. The rates of return to sports at any level or to the preinjury level were 79.3% and 61.9%, respectively. A total of 55.9% of the patients cited psychological factors as the primary reason for not returning to sports. The pooled estimate showed that patients who returned to sports had a significantly higher Shoulder Instability‐Return to Sport After Injury score ( P < 0.00001) than those who did not, with a mean difference of 30.24 (95% CI 24.95–35.53; I 2 = 0%; n.s.). Conclusions Psychological factors have a substantial impact on the rate of return to sports after anterior shoulder instability surgery. Patients who returned to sports had significantly higher psychological readiness than those who did not return to sports. Based on these results, healthcare professionals should include psychological and functional measurements when assessing athletes’ readiness to return to sports. Level of evidence Level IV.

AbstractIntroduction/AimsUltrasound shear wave elastography (SWE) of the thenar muscles has the potential to provide a simple and noninvasive assessment of the severity of carpal tunnel syndrome (CTS), but its reliability is unknown. The purpose of this study was to assess the intra‐ and inter‐rater reliability of SWE measurements of the elastic modulus of individual thenar muscles, to assess their suitability for clinical application.MethodsFourteen healthy volunteers, seven male and seven female, participated in this study. The elastic modulus of the thenar muscles was measured with SWE, with two independent examiners to assess inter‐rater reliability. The first examiner also performed a second measurement after an interval of least 1 day to assess intra‐rater reliability. Reliability was evaluated using an intraclass correlation coefficient (ICC) and 95% confidence interval (CI).ResultsFor the abductor pollicis brevis (APB) and opponens pollicis (OPP), the CI of ICC in intra‐rater reliability was 0.47–0.85 and 0.56–0.88, respectively. The CI of ICC in inter‐rater reliability was 0.27–0.78 for the APB and 0.22–0.76 for the OPP. The ICCs of intra‐ and/or inter‐rater reliability of other thenar muscles were less than 0.5.DiscussionIn this study, SWE evaluations of thenar muscles were quite variable in terms of their reliability. A larger study will be needed to determine the source of this variability, improve reliability, and assess the value of SWE in the evaluation of the severity of CTS.