BACKGROUND: Acromial stress fracture (ASF) is an uncommon but acknowledged complication of reverse total shoulder arthroplasty (RTSA). There is no standardised method to directly measure the bone mineral density of the acromion to allow a detailed analysis of the potential mechanism of ASF. The aim is to establish a reliable and reproducible technique for measurement of acromial density on computer tomography (CT).
METHODS: A retrospective review on CT scans obtained for three groups of patients: those planned for RTSA (n = 26); age and gender-matched non-operative (n = 26); and young non-operative patients (n = 28) were performed. Standardised axial images of 1 mm thickness at 1 mm increments were created following horizontal straightening on the coronal and sagittal views. To assess inter-rater reliability, two senior CT radiographers performed density measurements using standard region of interest (ROI) tool on the CTs with the ROI placed on the mid (ROI 1) and posterior (ROI 2) acromion. ROIs were selected as the most common locations for acromion fracture post RTSA. Measurements were repeated at least 6 weeks apart. Intra-class coefficients (ICC) were used to determine intra- and inter-rater reliability.
RESULTS: ICCs demonstrated good to high intra-rater and inter-rater reliability for both ROI 1 and ROI 2 across all three groups. The lower margin of 95% confidence intervals was more than 0 for all intra-class coefficients.
CONCLUSIONS: This study demonstrates a reliable method of measuring acromion density on CT. This method can be used to assess bone mineral density in the clinical setting and in future studies investigating ASF following RTSA.

OBJECTIVE: Rotator cuff tears (RCTs) are a major cause of shoulder pain and disability, affecting millions worldwide. Understanding the risk factors and developing reliable predictive measures for RCTs is essential for early diagnosis, targeted prevention, and effective treatment of this patient population. This study seeks to enhance our understanding by analyzing the acromiohumeral distance (AHD) and Constant-Murley Score (CMS) in patients with and without RCTs, thereby aiding the development of a predictive model aimed at improving clinical outcomes and prevention strategies in rotator cuff pathology.
METHODS: This retrospective analysis involved 201 patients with shoulder pain, categorized into RCT (n = 72) and no RCTs (N-RCTs, n = 129) groups based on Magnetic Resonance Imaging (MRI) findings. We compared demographics, AHD, CMS, and rotator cuff status between groups and utilized logistic regression for identifying RCT predictors, leading to the development of a multifactorial predictive model.
RESULTS: The mean AHD was 6.60 ± 1.12 mm. The RCT group showed a marginally higher AHD than the N-RCT group (p = 0.669). CMS scores were significantly lower in the RCT group (p < 0.001). Dominant side involvement (Odds Ratio (OR) 2.244), type III acromion (OR 6.106), and lower CMS (OR 0.938) significantly correlated with RCTs. The predictive model demonstrated an area under the curve (AUC) of 0.701 for RCT diagnosis.
CONCLUSIONS: Reduced CMS, dominance of the affected side, and type III acromion emerged as key risk factors for RCTs. Our predictive model, incorporating these factors, holds promise for RCT diagnosis, with future studies needed for further validation.

Objective: To compare the clinical effect of modified anterolateral and traditional acromioplasty in arthroscopic rotator cuff repair. Methods: The clinical data of 92 patients with total rotator cuff tears admitted to the Department of Joint Surgery of Jinhua Central Hospital from January 2016 to December 2019 were retrospectively analyzed. Of the patients, 42 were male, 50 were female, with a mean age of (57.1±13.2) years. Among them, 42 patients underwent traditional acromioplasty during arthroscopic rotator cuff repair (traditional group), and 50 underwent modified anterolateral acromioplasty (modified group). The preoperative and postoperative shoulder function of the patients in the two groups were evaluated and compared by using the University of California Los Angeles (UCLA), the rating scale of the American Shoulder and Elbow Surgeons (ASES), and the constant Murley shoulder score scale. And the preoperative and postoperative pain of patients was evaluated with visual analog scale (VAS). The incidence of rotator cuff retears 12 months after operation was counted. Results: There was no statistically significant differences in general information such as gender, age, affected side and course of disease between the two groups before the surgery (all P<0.05). All patients were followed up for (12.9±1.1) months. There was no significant differences in the UCLA score (31.4±3.0 vs 32.0±2.5), ASES score (13.1±0.7 vs 13.3±0.6), Constant Murley shoulder score (92.1±6.6 vs 94.3±4.6) and VAS score (1.5±0.8 vs 1.2±1.1) between the traditional group and the modified group 12 months after the operation (all P>0.05). The preoperative CSA (36.0°±1.7°) in the traditional group did not differ significantly from that at 12 months postoperatively (35.5°±1.2°) (P=0.270); the postoperative CSA at 12 months (30.8°±2.5°) in the modified group was significantly smaller than that before the operation (36.5°±1.9°), and also was smaller than that in the traditional group 12 months after the operation (35.5°±1.2°) (both P<0.05). At 12 months after operation, the rate of rotator cuff tears in the traditional group and modified group was 16.7% (7/42) and 4.0% (2/50), respectively (P=0.045). Conclusions: Traditional and modified anterolateral acromioplasty in treating total rotator cuff tears using arthroscopic rotator cuff repair can significantly improve shoulder joint function. However, modified anterolateral acromioplasty significantly reduces the CSA value and decreases the incidence of rotator cuff re-tears.
目的： 比较关节镜下传统肩峰成形术与改良前外侧肩峰成形术治疗中度肩袖撕裂的疗效。 方法： 回顾性分析2016年1月至2019年12月金华市中心医院关节外科收治的92例中等肩袖撕裂患者的临床资料。其中男42例，女50例；年龄（57.1±13.2）岁。所有患者根据手术方式不同分成2组：传统组42例（行关节镜下传统肩峰成形术）和改良组50例（行关节镜下改良前外侧肩峰成形术）。术前、术后12个月利用美国加州大学洛杉矶分校评分（UCLA）、美国肩肘外科协会评分（ASES）、Constant-Murley肩关节评分评估和比较两组患者肩关节功能，利用视觉模拟评分（VAS）评估患者的疼痛情况，在肩关节正位X线片上测量肩关节临界肩角（CSA），并进行组内和组间比较，统计术后12个月肩袖再撕裂的发生率。 结果： 两组患者术前性别、年龄、侧别、病程等一般资料比较差异均无统计学意义（均P<0.05）。所有患者术后随访（12.9±1.1）个月。术后12个月传统组UCLA评分（31.4±3.0）分、ASES评分（13.1±0.7）分、Constant-Murley肩关节评分（92.1±6.6）分、VAS评分（1.5±0.8）分与改良组［（32.0±2.5）分、（13.3±0.6）分、（94.3±4.6）分、（1.2±1.1）分］差异均无统计学意义（均P>0.05）；两组术后12个月上述评分均较术前显著改善，差异均有统计学意义（均P<0.05）。传统组术前的CSA（36.0°±1.7°）与术后12个月（35.5°±1.2°）比较差异无统计学意义（P=0.270）；改良组术后12个月CSA（30.8°±2.5°）小于术前的36.5°±1.9°和传统组术后12个月的35.5°±1.2°（均P<0.05）。术后12个月，改良组肩袖再撕裂率低于传统组［4.0%（2/50）比16.7%（7/42）］（P=0.045）。 结论： 对于中等肩袖撕裂患者，关节镜下行传统肩峰成形术和改良肩峰前外侧成形术均能显著改善患者肩关节功能，但改良肩峰前外侧成形术能显著减小CSA值，降低肩袖再撕裂的发生率。.

The purpose of this study was to identify the relationship between scapula morphology and rotator cuff tears (RCT). Hundred seventeen shoulders with and 87 shoulders without RCTs were included in this retrospective study. The critical shoulder angle (CSA) and lateral acromion angle in the coronal view, and the acromial coverage angle (ACA) and coracoid and scapular spine angle (CSSA) in the sagittal view were evaluated using 3-dimensional computed tomography. The glenoid anterior tilt, anterior acromial projection angle (AAPA), coracoid process angle, scapular spine angle (SSA), and inferior angle angle (IAA) with respect to the scapular plane were measured in the sagittal view. In univariate logistic regression analysis, CSA, ACA, AAPA, SSA, and IAA were significantly greater in shoulders with RCTs, whereas CSSA was greater in shoulders without RCTs. In multivariate logistic regression analysis, CSA and IAA were greater in shoulders with RCT and were significantly associated with this condition (P=.00073, P=.0032). This study has shown us that RCTs were associated with a greater curvature of the scapular body and greater CSA and IAA.

BACKGROUND: The aim of this study was to evaluate the interobserver reliability of measurements of the Acromiohumeral Distance (AHD) first described by Golding et al., the Critical Shoulder Angle (CSA), the Acromion Index with Glenoid Humeral (GH) and Glenoid Acromial (GA) distances, following the measuring method by Nyffeler et al., the Lateral Acromion Angle (LAA), as well as the morphology of the acromion according to Bigliani and the humeral head position according to Maloney in X-rays and MRI. Furthermore, the study assessed the correlation of measurement results in X-ray with those in MRI for AHD, CSA, GA, GH, AI, and LAA.
METHODS: A total of 187 patients who underwent shoulder joint X-ray and MRI examinations from 09/2016 to 05/2023 were included in the study. Patients with poor imaging quality, arthrosis or radical prior surgeries, like shoulder prosthetic surgery, status post humerus fractures, that have undergone surgery and therefore changed the anatomical features were excluded, what lead to a total study population of 78. X-ray measurements were performed by two observers in the true anteroposterior view, so that the humeral head and the glenoid are shown without overlap, providing a clear view into the joint space. MRI measurements were performed in oblique coronal MRI slices, using the most accurately depicted glenoid surface as a landmark.
RESULTS: Interobserver measurement results showed a significance with p < 0.001 for the assessment of acromion type according to Bigliani, humeral head offset assessment according to Maloney, and AHD. No significance was found for interobserver reliability in measuring LAA. Additionally, there was a high correlation of measurement results in X-ray with measurements in MRI for, CSA, GH/GA, and consequently AI, a good correlation for AHD but no correlation could be shown for LAA.
CONCLUSIONS: These findings provide valuable insights into the robustness of radiological parameters for evaluating shoulder pathology, offering promising prospects for clinical applications and further research. Nevertheless, the specific methodological considerations and patient characteristics should be taken into account when interpreting the results to ensure their accurate application in clinical practice.

UNASSIGNED: Morphological differences among various ethnicities can significantly impact the reliability of acromiohumeral interval (AHI) measurements in diagnosing massive rotator cuff tears. This variation raises questions about the generalizability of AHI studies conducted in Western populations to the Asian population. Consequently, the primary objective of this study was to develop a novel parameter that can enhance the diagnosis of massive rotator cuff tears, irrespective of morphometric disparities between individuals of different ethnic backgrounds.
UNASSIGNED: A 10-year retrospective analysis of shoulder arthroscopic surgery patients was conducted, categorizing them into 3 groups based on intraoperative findings: those without rotator cuff tears, those with non-massive tears, and those with massive tears. AHI-glenoid ratio (AHIGR) was measured by individuals with varying academic backgrounds, and its diagnostic performance was compared to AHI. Sensitivity, specificity, accuracy, and intra- and inter-rater reliability were evaluated.
UNASSIGNED: AHIGR exhibited significantly improved sensitivity, specificity, and accuracy as a diagnostic tool for massive rotator cuff tears, compared to AHI. A proposed cut-off point of AHIGR ≤ 0.2 yielded comparable results to AHI < 7 mm. Intra- and inter-rater reliability was excellent among different observers.
UNASSIGNED: AHIGR emerges as a promising diagnostic tool for massive rotator cuff tears, offering improved sensitivity and specificity compared to AHI. Its reproducibility among diverse observers underscores its potential clinical utility. While further research with larger and more diverse patient cohorts is necessary, AHIGR offers significant potential as a reference for enhancing the assessment of massive rotator cuff tears.

BACKGROUND: This study validated the accuracy of the acromion marker cluster (AMC) and scapula spinal marker cluster (SSMC) methods compared with upright four-dimensional computed tomography (4DCT) analysis.
METHODS: Sixteen shoulders of eight healthy males underwent AMC and SSMC assessments. Active shoulder elevation was tracked using upright 4DCT and optical motion capture system. The scapulothoracic and glenohumeral rotation angles calculated from AMC and SSMC were compared with 4DCT. Additionally, the motion of these marker clusters on the skin with shoulder elevation was evaluated.
RESULTS: The average differences between AMC and 4DCT during 10°-140° of humerothoracic elevation were - 2.2° ± 7.5° in scapulothoracic upward rotation, 14.0° ± 7.4° in internal rotation, 6.5° ± 7.5° in posterior tilting, 3.7° ± 8.1° in glenohumeral elevation, - 8.3° ± 10.7° in external rotation, and - 8.6° ± 8.9° in anterior plane of elevation. The difference between AMC and 4DCT was significant at 120° of humerothoracic elevation in scapulothoracic upward rotation, 50° in internal rotation, 90° in posterior tilting, 120° in glenohumeral elevation, 100° in external rotation, and 100° in anterior plane of elevation. However, the average differences between SSMC and 4DCT were - 7.5 ± 7.7° in scapulothoracic upward rotation, 2.0° ± 7.0° in internal rotation, 2.3° ± 7.2° in posterior tilting, 8.8° ± 7.9° in glenohumeral elevation, 2.0° ± 9.1° in external rotation, and 1.9° ± 10.1° in anterior plane of elevation. The difference between SSMC and 4DCT was significant at 50° of humerothoracic elevation in scapulothoracic upward rotation and 60° in glenohumeral elevation, with no significant differences observed in other rotations. Skin motion was significantly smaller in AMC (28.7 ± 4.0 mm) than SSMC (38.6 ± 5.8 mm). Although there was smaller skin motion in AMC, SSMC exhibited smaller differences in scapulothoracic internal rotation, posterior tilting, glenohumeral external rotation, and anterior plane of elevation compared to 4DCT.
CONCLUSIONS: This study demonstrates that AMC is more accurate for assessing scapulothoracic upward rotation and glenohumeral elevation, while SSMC is preferable for evaluating scapulothoracic internal rotation, posterior tilting, glenohumeral external rotation, and anterior plane of elevation, with smaller differences compared to 4DCT.

OBJECTIVE: To determine the short-term complication rates following open reduction and internal fixation of scapula fractures, factors affecting the development of adverse events, and complication rates based on the anatomic location of the fracture.
METHODS: Thirty-day complication rates for patients who underwent open reduction and internal fixation of the scapula were compared between glenoid, body, coracoid, and acromion fracture locations, as identified by International Classification of Disease codes. Possible adverse events included postoperative surgical site infection, renal insufficiency, intubation, pneumonia, deep vein thrombosis, pulmonary embolism, urinary tract infection, wound dehiscence, stroke, and blood transfusion.
RESULTS: A total of 251 scapula fractures were identified, with 161 having known fracture locations: 105 glenoid, 20 body, 9 coracoid, and 27 acromial fractures. The rate of any adverse event for all scapular fractures was 2.0%, with no significant difference between anatomic locations (p = 0.79). The overall rates of transfusion, surgical site infection, and return to OR were 0.4%, 0.8%, and 3.98%. Steroid use associated with a significantly increased risk of any adverse event (OR: 55.57, p = 0.038) and outpatient status demonstrated a protective effect on reoperation (OR: 0.11, p = 0.014). There were no significant differences in the rates between groups [transfusion (p = 0.91); surgical site infection (p = 0.17); reoperation (p = 0.85)].
CONCLUSIONS: Complication rates within thirty days of ORIF for scapula fracture were low. Reoperation was the most common complication, followed by surgical site infection, wound dehiscence, stroke, transfusion, and pneumonia. Steroid use was a risk factor for developing any adverse event, and outpatient status was protective against reoperation. The 30-day complication profile of glenoid, body, coracoid, and acromial fractures was not significantly different. The low complication rates support the relative short-term safety of operative intervention with internal fixation.
METHODS: Level III.

Background: Reverse total shoulder arthroplasty (RSA) significantly impacts deltoid length, tension, and structure. Studies have extensively investigated various modifications in deltoid characteristics, such as perfusion, elasticity, caliber, histological changes, and strength post-RSA. However, to date, there is a notable absence of research evaluating changes in bone mineral density (BMD) at the deltoid muscle origin after the RSA procedure. Methods: A retrospective analysis of a consecutive series of RSAs performed between May 2011 and May 2022 was conducted. Inclusion criteria comprised primary RSAs with both preoperative and last follow-up shoulder CT scans and a minimum follow-up of 12 months. Trabecular attenuation measured in Hounsfield units (HU) was calculated using a rapid region-of-interest (ROI) method. BMD analysis involved segmenting three ROIs in both pre- and postoperative CT scans of each patient: the acromion, clavicle, and spine of the scapula. Results: A total of 44 RSAs in 43 patients, comprising 29 women and 14 men, were included in this study. The mean follow-up duration was 49 ± 22.64 months. Significant differences were observed between preoperative and postoperative HU values in all analyzed regions. Specifically, BMD increased in the acromion and spine, while it decreased in the clavicle (p-values 0.0019, <0.0001, and 0.0088, respectively). Conclusions: The modifications in shoulder biomechanics and, consequently, deltoid tension post-implantation result in discernible variations in bone quality within the analyzed regions. This study underscores the importance of thorough preoperative patient planning. By utilizing CT images routinely obtained before reverse shoulder replacement surgery, patients at high risk for fractures of the acromion, clavicle, and scapular spine can be identified.

Accurate arm circumference (AC) measurement is required for accurate blood pressure (BP) readings. Standards stipulate measuring arm circumference at the midpoint between the acromion process (AP) and the olecranon process. However, which part of the AP to use is not stipulated. Furthermore, BP is measured sitting but arm circumference is measured standing. We sought to understand how landmarking during AC measurement and body position affect cuff size selection. Two variations in measurement procedure were studied. First, AC was measured at the top of the acromion (TOA) and compared to the spine of the acromion (SOA). Second, standing versus seated measurements using each landmark were compared. AC was measured to the nearest 0.1 cm at the mid-point of the upper arm by two independent observers, blinded from each other\'s measurements. In 51 participants, the mean (±SD) mid-AC measurement using the anchoring landmarks TOA and SOA in the standing position were 32.4 cm (±6.18) and 32.1 cm (±6.07), respectively (mean difference of 0.3 cm). In the seated position, mean arm circumference was 32.2 (±6.10) using TOA and 31.1 (±6.03) using SOA (mean difference 1.1 cm). Kappa agreement for cuff selection in the standing position between TOA and SOA was 0.94 (p < 0.001). The landmark on the acromion process can change the cuff selection in a small percentage of cases. The overall impact of this landmark selection is small. However, standardizing landmark selection and body position for AC measurement could further reduce variability in cuff size selection during BP measurement and validation studies.