Effect of critical shoulder angle on deltoid muscle strength reduction in patients with rotator cuff tears / 中国修复重建外科杂志

OBJECTIVE@#To investigate the synergistic interaction between the deltoid muscle and the rotator cuff muscle group in patients with rotator cuff tears (RCT), as well as the impact of the critical shoulder angle (CSA) on deltoid muscle strength.@*METHODS@#A retrospective analysis was conducted on clinical data from 42 RCT patients who met the selection criteria and were treated between March 2022 and March 2023. There were 13 males and 29 females, with an age range of 42-77 years (mean, 60.5 years). Preoperative visual analogue scale (VAS) score was 6.0±1.6. CSA measurements were obtained from standard anteroposterior X-ray films before operation, and patients were divided into two groups based on CSA measurements: CSA>35° group (group A) and CSA≤35° group (group B). Handheld dynamometry was used to measure the muscle strength of various muscle group in the shoulder (including the supraspinatus, infraspinatus, subscapularis, and anterior, middle, and posterior bundles of the deltoid). The muscle strength of the unaffected side was compared to the affected side, and muscle imbalance indices were calculated. Muscle imbalance indices between male and female patients, dominant and non-dominant sides, and groups A and B were compared. Pearson correlation analysis was used to examine the relationship between muscle imbalance indices and CSA as well as VAS scores.@*RESULTS@#Muscle strength in all muscle groups on the affected side was significantly lower than on the unaffected side ( P<0.05). The muscle imbalance indices for the supraspinatus, subscapularis, infraspinatus, and anterior, middle, and posterior bundles of the deltoid were 14.8%±24.4%, 5.9%±9.7%, 7.2% (0, 9.1%), 17.2% (5.9%, 26.9%), 8.3%±21.3%, and 10.2% (2.8%, 15.4%), respectively. The muscle imbalance indices of the anterior bundle of the deltoid, supraspinatus, and infraspinatus were significantly lower in male patients compared to female patients ( P<0.05); however, there was no significant difference in muscle imbalance indices among other muscle groups between male and female patients or between the dominant and non-dominant sides ( P>0.05). There was a positive correlation between the muscle imbalance indices of infraspinatus and VAS score ( P<0.05), and a positive correlation between CSA and the muscle imbalance indices of middle bundle of deltoid ( P<0.05). There was no correlation between the muscle imbalance indices of other muscle groups and VAS score or CSA ( P>0.05). Preoperative CSA ranged from 17.6° to 39.4°, with a mean of 31.1°. There were 9 cases in group A and 33 cases in group B. The muscle imbalance indices of the anterior bundle of the deltoid was significantly lower in group A compared to group B ( P<0.05), while there was no significant difference in muscle imbalance indices among other muscle groups between group A and group B ( P>0.05).@*CONCLUSION@#Patients with RCT have a phenomenon of deltoid muscle strength reduction, which is more pronounced in the population with a larger CSA.

A morphometric study of spinoglenoid notch, subcoracoacromial arch, and spinous process of the scapula on shoulder impingement

Introduction: Morphometric study of spinoglenoid notch, coracoacromial arch, and another measurement of the scapulae are required to understand the reason for spasms of common muscle due to supraspinatus tendinitis, nerve compression over the spinoglenoid notch. Therefore, the aim of this study was to discuss the subcoracoacromial arch, deviation of the spinous process, and measurement of the spinoglenoid notch. Materials and Methods: This study was conducted at the Department of Anatomy, Sri Venkateshwaraa Medical College Hospital & Research Centre, Chennai, Tamil Nadu, India on 70 scapulae that include 58 non-articulated scapulae and 12 articulated scapulae. All the measurements were performed with a vernier caliper and the alignment of the spinous process of the scapula was measured with a goniometer. All the measurements are compared on both sides. Results: All the measurements were performed and presented as mean with standard deviation. We found the variation of diameter between the left and right sides. Spinoglenoid notch diameters were noted as anterior to posterior right 2.97 ± 0.37 cm, left 3.06 ± 0.56 cm and medial to lateral right 1.36 ± 0.14 cm, left 1.4 ± 0.08 cm. Subcoracoacromial arch was observed as right 1.85 ± 0.23 cm and left 1.92 ± 0.4 cm. The direction of the spinous process of the scapula was noted as right 21.50º ± 8.50 and left 18.8º ± 7.89. Conclusion: The present morphometric study findings may give a different approach to supraspinatous tendinits, shoulder instability, and dislocation cases due to morphometric changes present in the spinous process, acromion process, glenoid cavity, and spinoglenoid notch of the scapula. These morphometric studies on scapula can help radiologists, orthopedicians, and physiotherapists to plan patient management.

Diagnóstico de roturas del manguito rotador por ecografía y resonancia magnética: ¿la morfología acromial influye en los resultados? / Ultrasound and magnetic resonance imaging diagnosis for rotator cuff tears: does acromial morphology affect the results?

INTRODUCCIÓN Actualmente no existen estudios que evalúen la concordancia entre la ecografía (ECO) y la resonancia magnética (RM) observando parámetros como el índice acromial (IA) y el ángulo crítico (AC) para roturas del manguito rotador (MR). Se considera que la mayor cobertura de la huella por un IA o AC incrementados podría afectar la adecuada visualización del MR en estudios de ECO al interponerse entre el complejo tendíneo y el transductor ecográfico. OBJETIVO Estimar la concordancia de la ECO y la RM en el diagnóstico de pacientes con roturas del MR confirmadas por artroscopia con IA y AC mayores al promedio normal (0.7 y 35°, respectivamente). Secundariamente, determinar si la concordancia diagnóstica es comparable entre tipos de rotura (espesor completo o parciales). MATERIALES Y MÉTODOS Estudio retrospectivo de una serie consecutiva de 100 pacientes con roturas totales o parciales del MR confirmadas por artroscopia. RESULTADOS La edad media del grupo de estudio fue de 55,7 ± 10,5 años. La media del IA fue de 0,77 ± 0,08, y la del AC, de 37,42° ± 5,88°. La concordancia entre la ECO y la RM y el IA fue > 0,7 de 56,7% (K = 0,27; p = 0,01); y < 0,7 de 35,7% (K = 0,01; p = 0,46), respectivamente. Y la concordancia entre la ECO y la RM y el AC fue > 35° de 61,5% (K = 0,32; p = 0,001); y < 35° de 33,3% (K = -0,00; p = 0,52), respectivamente. CONCLUSIÓN La concordancia diagnóstica de la ECO comparada con la de la RM, en pacientes con roturas del MR confirmada por artroscopia y con IA y AC mayores al promedio normal, fue justa. La concordancia diagnóstica de la ECO comparada con la RM, en pacientes con IA y AC menores al promedio normal, fue pobre. La capacidad diagnóstica fue similar entre la ECO y la RM para roturas parciales y totales.

INTRODUCTION Currently, there are no studies that evaluate the agreement between ultrasound (US) and magnetic resonance imaging (MRI) scans in rotator cuff (RC) tears by the observation of parameters such as the acromial index (AI) and critical shoulder angle (CSA). We hypothesize that the greater coverage of the footprint by increased AI or CSA could affect the proper visualization of the RC in US scans by its interposition between the tendinous complex and the US transducer. OBJETIVE To estimate the agreement between US and MRI in the diagnosis of patients with RC tears confirmed by arthroscopy and with AI and CSA greater than the normal average values (0.7 and 35° respectively). The secondary objective is to determine if the diagnostic agreement is comparable regarding different types of tear (partial and complete). MATERIALS AND METHODS A retrospective study of a consecutive case series of 100 patients with partial or complete RC tears confirmed by arthroscopy. RESULTS The mean age of the study group was of 55.7 10.5 years. The mean AI was of 0.77 0.08, and the mean CSA was of 37.42° 5.88°. The agreement regarding the US, the MRI and the AI was > 0.7 of 56.7% (K » 0.27; p » 0.01); and < 0.7 of 35.7% (K » 0.01; p » 0.46) respectively. And the agreement regarding the US, the MRI and the CSA was > 35° of 61.5% (K » 0.32; p » 0.001); and < 35° of 33.3% (K »-0.00; p » 0.52) respectively. CONCLUSION The diagnostic agreement of the US compared with the MRI, in patients with RC tears confirmed by arthroscopy and with AI and CSA greater than the normal average values was fair. The diagnostic agreement of the US compared with the MRI, in patients with AI and CSA lower than the normal average values was poor. The diagnostic performance of the IS and MRI was similar for partial and complete tears.

Difference of Critical Shoulder Angle (CSA) According to Minimal Rotation: Can Minimal Rotation of the Scapula Be Allowed in the Evaluation of CSA?

BACKGROUND: Minimal rotation of the scapula may affect the measurement of critical shoulder angle (CSA). We investigated the difference in the CSA measured in minimal rotation between the patients with rotator cuff tear and those without non-rotator cuff tear and the CSA measurement error by comparing with computed tomography (CT). METHODS: We retrospectively reviewed patients with full-thickness rotator cuff tear and whose X-ray views correspond to Suter-Henninger classification type A1 and C1. The CSA values between the normal control group (without rotator cuff tear) and the rotator cuff tear group were compared according to A1 type and C1 type. In the rotator cuff tear group, we compared the CSA values measured by using X-ray and CT. RESULTS: A total of 238 patients (rotator cuff tear group, 139 patients; normal cuff group, 99 patients) were included in this study. The mean CSA of the rotator cuff tear group was 33.4° ± 3.5°, and that of the normal cuff group was 32.6° ± 3.9° (p = 0.085). On comparison of the CSA according to the Suter-Henninger classification type, the CSA values on the A1 type view and C1 type view were 32.7° ± 3.5° and 33.7° ± 3.5°, respectively, in the rotator cuff tear group and 30.5° ± 3.1° and 33.1 ± 3.9°, respectively, in the normal cuff group (p = 0.024 and p = 0.216, respectively). The mean CSA was 32.5° ± 3.1° in CT and 33.3° ± 3.2° in X-ray (p = 0.184). On comparison of the CSA according to the Suter-Henninger classification type, the CSA values on the A1 type view and C1 type view were 32.6° ± 3.6° and 32.5° ± 2.4°, respectively, in CT and 32.5° ± 3.5° and 34.2° ± 2.6°, respectively, in X-ray (p = 0.905 and p = 0.017, respectively). CONCLUSIONS: The X-ray view corresponding to Suter-Henninger classification type A1 or CT-reconstructed image can be used to reduce the measurement error and obtain reliable CSA values. The CSA measured on the X-ray view corresponding to Suter-Henninger classification type A1 may be related with rotator cuff tear.

Predictors of shoulder degeneration in the Kwazulu-Natal population of South Africa / Indicadores de la degeneración del hombro en la poblacion Kwazulu/Natal de Sudáfrica

SUMMARY: The critical shoulder angle and acromion index are conventional radiological tools employed as predictors of shoulder degeneration. As they represent the static components of glenohumeral stability, the scapulo-humeral geometry and underlying subacromial tissue appear as the resultant cause-effect factors. Consequently, the purpose of this study was to investigate the critical shoulder angle and acromion index as interrelated parameters within the South African population. The measurement of both biomechanical parameters was conducted on two-hundred and sixty (n = 260) true AP radiographs. This was a cross-sectional study that also incorporated the demographic representation of the population group which was analysed accordingly. The mean values recorded for both the critical shoulder angle (36.31±5.84º) and acromion index (0.74±0.13) suggested rotator cuff arthropathy. The results confirmed the theories of Nyffeler et al. (2006) and Moor et al. (2012) who alluded to glenoid inclination and the acromial coverage over the humeral head. A significant proportionality correlation, verified by a P value of 0.000, was established between the acromion index and critical shoulder angle which may assist to differentiate between normal asymptomatic shoulders and those with cuff disease. Furthermore, these predictors of shoulder degeneration may present as a preventative tool against tear progression.

RESUMEN: El ángulo crítico del hombro y el índice acromial son herramientas radiológicas convencionales empleadas como indicadores de la degeneración del hombro. Debido a que representan los componentes estáticos de la estabilidad glenohumeral, la geometría escápulo-humeral y el tejido subacromial subyacente aparecen como los factores causa-efecto resultantes. En consecuencia, el propósito de este estudio fue investigar el ángulo crítico del hombro y el índice acromial como parámetros interrelacionados dentro de la población sudafricana. La medición de ambos parámetros biomecánicos se realizó en 260 radiografías antero-posteriores (AP). Se realizó un estudio transversal que también incorporó la representación demográfica del grupo de la población que fue analizada. Los valores medios registrados tanto para el ángulo crítico del hombro (36,31 ± 5,84º) como para el índice del acromión (0,74 ± 0,13) sugirieron una artropatía del manguito rotador. Los resultados confirmaron las teorías de Nyffeler et al. (2006) y Moor et al. (2012) que aludían a la inclinación glenoide y a la cobertura acromial sobre la cabeza humeral. Se estableció una correlación de proporcionalidad significativa, verificada por un valor de P de 0,000, entre el índice acromial y el ángulo crítico del hombro, lo que puede ayudar a diferenciar entre los hombros asintomáticos normales y aquellos con enfermedad del manguito rotador. Además, estos predictores de degeneración del hombro pueden ser útiles como una herramienta preventiva contra la progresión del desgarro.