Iida, Naoya

ABSTRACT Based on anecdotal observation of fatty infiltration (FI) of the opponens pollicis (OPP) muscle in patients with thumb carpometacarpal (CMC) Osteoarthritis (OA), we sought to examine the association of FI with CMC OA. We reviewed 747 consecutive 3 T wrist magnetic resonance imaging (MRI) studies for evidence of FI in the thenar muscles. This population was divided into two cohorts based on radiographic analysis: a cohort without thumb CMC OA ( n = 440) and a second cohort with thumb CMC OA ( n = 307), staged according to the Eaton–Littler classification. Statistical analysis using logistic regression was performed to investigate clinical factors associated with the presence of FI in the thenar muscles. FI was present in 133 patients with CMC OA (43.3%). FI, when present, was located only in the OPP. We found no OPP FI in the cohort without CMC OA (440 patients). Among patients with CMC OA, increasing age, male sex and advanced OA stage were significantly associated with the presence of OPP FI. OPP FI is a frequent finding in CMC OA. This FI could affect the biomechanical function of the OPP. In the future, we plan to analyze clinical outcomes in CMC OA patients with and without FI, and more focused in vivo studies of OPP function. OPP FI could potentially affect the function and the stability of the thumb CMC joint in patients with CMC OA. Orthopaedic Research Society. Journal of Orthopaedic Research® 00:00–00, 2026.

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.

ABSTRACT Introduction Acute Compartment Syndrome (ACS) is a severe trauma caused by elevated intra-muscle-compartment pressure (ICP). The current standard method for diagnosis is to insert a needle into the muscle sterilely under anesthesia. However, to secure the environment is sometimes not easy and leads to delays in diagnosis. Recently, we have focused on shear wave ultrasound elastography (SWE) as an alternative, which can be done concisely in unclean environment and without anesthesia. We would like to report the usefulness of SWE for ACS diagnosis using 2-pedal walking turkey model recently developed in our lab. Materials and Methods A total of 32 1-year-old Bourbon turkeys were used. 5% solution of chicken albumin was infused continuously into the tibialis cranialis (TC) muscle using IV pump. The ICP was increased stepwise from 0 to 50 mmHg. During the rising of ICP, the correlation between values of SWE (kPa) and ICP (mmHg) was measured. After the ICP reached 50 mmHg, half of the turkeys were maintained at this pressure for 2 hours and the rest for 6 hours. After infusion, a fasciotomy was performed on the half turkey. Half of the turkeys were euthanized after 2 weeks and the rest after 6 weeks. SWE of TC muscle and walking gait data on turkeys using a portable walkway system were measured weekly until euthanasia. At euthanasia, isometric tetanic muscle force (ITF) tests to TC muscle and histological evaluations were performed. Results SWE value (kPa) was highly significantly correlated to the actual ICP (mmHg) (R2 = 0.91). Stance of ACS side leg were significantly extended, and swing of the control side shortened from the second to the third week after ACS in the 6 hours infusion-no-fasciotomy group (P < 0.05*). ITF was significantly reduced mainly in the 6 hours infusion group (P < 0.05*). Histological evaluation revealed that in the 6 hours infusion and 6 weeks survival group, both the muscle fiber and intercellular distances were significantly expanded (P < 0.05). Conclusion SWE seems to be a substitute measure of ICP in diagnosing ACS. With regard to our in vivo ACS model using turkey, survival at 50 mmHg ICP for 6 hours and 6 weeks post ACS would be an appropriate situation.

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.