Critical shoulder angle (CSA) is the angle between the superior and inferior bony margins of the glenoid and the most lateral border of the acromion. The acromial index (AI) is the distance from the glenoid plane to the acromial lateral border and is divided by the distance from the glenoid plane to the lateral aspect of the humeral head. Although both are used for predicting shoulder diseases, research on their accuracy in predicting supraspinatus tendinopathy in patients with shoulder pain is limited. Data were retrospectively collected from 308 patients with supraspinatus tendinopathy between January 2018 and December 2019. Simultaneously, we gathered the data of 300 patients with shoulder pain without supraspinatus tendinopathy, confirmed through ultrasound examination. Baseline demographic data, CSA, and AI were compared using the independent Student’s t test and Mann–Whitney U test. Categorical variables were analyzed using the chi-square test. A receiver operating characteristic curve (ROC) analysis was performed to investigate the accuracy of CSA and AI for predicting supraspinatus tendinopathy, and the optimal cut-off point was determined using the Youden index. No statistical differences were observed for age, sex, body mass index, evaluated side (dominant), diabetes mellitus, and hyperlipidemia between the groups. The supraspinatus tendinopathy group showed higher CSAs (p < 0.001) than did the non-supraspinatus tendinopathy group. For predicting supraspinatus tendinopathy, the area under the curve (AUC) of ROC curve of the CSA was 76.8%, revealing acceptable discrimination. The AUC of AI was 46.9%, revealing no discrimination. Moreover, when patients with shoulder pain had a CSA > 38.11°, the specificity and sensitivity of CSA in predicting supraspinatus tendinopathy were 71.0% and 71.8%, respectively. CSA could be considered an objective assessment tool to predict supraspinatus tendinopathy in patients with shoulder pain. AI revealed no discrimination in predicting supraspinatus tendinopathy in patients with shoulder pain.

Background: This systematic review and meta-analysis aimed to assess the efficacy of prolotherapy compared to control or placebo-based treatments. Methods: A comprehensive search of PubMed, Ovid, and Scopus was conducted up to April 2025. Inclusion criteria encompassed clinical studies comparing prolotherapy with control or placebo treatments and evaluating outcomes such as pain, function, and range of motion. Results: Eight studies involving 431 participants met the inclusion criteria. Patient-reported outcomes, including pain visual analog scale and Shoulder Pain and Disability Index, showed no statistically significant differences between prolotherapy and controls. Prolotherapy demonstrated a small but statistically significant improvement in shoulder abduction (mean difference, 7.08°; 95% CI, 2.49°–11.66°). Other range of motion measures, such as forward flexion, internal rotation, and external rotation, showed no significant differences. Radiographic outcomes, including tendon thickness and elasticity, suggested potential structural benefits but did not consistently translate to clinical improvements. Conclusions: Prolotherapy is not superior to control treatments for rotator cuff tendinopathy. While it offers minor gains in shoulder abduction, its clinical benefits are limited. Level of evidence: III.

Background: Existing research on the influence of symptom duration on the outcomes of ultrasound-guided shoulder hydrodilatation for frozen shoulder remains limited. This prospective analytical study aims to investigate the associations between symptom duration and other potential factors and shoulder function following ultrasound-guided shoulder hydrodilatation.Methods: This study was conducted at the Department of Rehabilitation Medicine, King Chulalongkorn Memorial Hospital, and involved patients with frozen shoulder who underwent ultrasound-guided shoulder hydrodilatation. Using convenience sampling, 72 participants were recruited, and 36 were classified into the early hydrodilatation group and 36 into the late hydrodilatation group. Outcome measures were the Oxford Shoulder Score (OSS), visual analog scale (VAS), and shoulder range of motion (ROM), which were assessed both before and 6 weeks after the hydrodilatation procedure.Results: Duration of symptoms, age, sex, history of diabetes mellitus, physiotherapy, and baseline shoulder ROM did not exhibit any association with OSS changes. However, a high VAS score at baseline was associated significantly with improved shoulder function following ultrasound- guided shoulder hydrodilatation (P=0.006).Conclusions: There was no association between the duration of symptoms and enhanced shoulder function after ultrasound-guided shoulder hydrodilatation in short-term assessments. Patients with higher baseline shoulder pain severity tended to experience greater improvements in shoulder function compared to those with milder pain levels.Level of evidence: III.

The critical shoulder angle (CSA) is associated with impingement and rotator cuff lesions, and ultrasound-guided corticosteroid injection is effective for subacromial bursitis. However, because the efficacy of this treatment varies, this study investigated the effect of the CSA on the efficacy of corticosteroid injection in the subacromial space. Patients who received a diagnosis of subacromial bursitis after a clinical physical examination and ultrasound were enrolled prospectively from May 2019 to December 2021. Patients’ baseline variables and CSAs were assessed before intervention. Patients’ shoulder pain and disability index (SPADI), visual analog scale (VAS), and shoulder joint range of motion (ROM) scores were assessed at 2, 6, and 12 weeks after ultrasound-guided corticosteroid injection. All participants were divided into CSA > 38° and CSA ≤ 38° groups. We conducted the intragroup and intergroup comparisons of the variables and performed Pearson analysis to identify potential correlations between the CSA and outcome parameters. A total of 55 patients were enrolled in this study. Of these, 28 were included in the CSA > 38° group and 27 in the CSA ≤ 38° group. The baseline variables of the two groups did not differ. In the intragroup and intergroup comparisons, although VAS, SPADI, and ROM scores improved up to 12 weeks after intervention, no difference was identified between groups. The Pearson analysis revealed a positive correlation (r = 0.30, p = 0.024) between the CSA and VAS scores before the intervention. However, no correlation was found between the CSA and follow-up parameters. The CSA was not associated with the clinical efficacy of ultrasound-guided corticosteroid injection for subacromial bursitis.