Beyond the Cuff: MR Imaging of Labroligamentous Injuries in the Athletic Shoulder

Anterior Labrum Periosteal Sleeve Avulsion Lesions of the Shoulder: A Scoping Review

Background

Anterior labrum periosteal sleeve avulsion (ALPSA) lesion of the shoulder is defined as a labral avulsion with an intact periosteum of the glenoid neck resulting in medial malattachment of the labrum, which is both nonanatomic and nonfunctional. It is relatively rare compared with Bankart lesions, and its results are usually reported in combination with other anterior labroligamentous lesions in the literature.

Purpose

To (1) assess the size and scope of the literature on ALPSA lesions, (2) highlight the importance of this lesion, and (3) distinguish between ALPSA and Bankart lesions in diagnostic and treatment strategies.

Study Design

Scoping review; Level of evidence, 4.

Methods

The PubMed, Scopus, Embase, and Google Scholar databases were searched with the keywords "ALPSA,""anterior labrum periosteal sleeve avulsion,""anterior labral periosteal sleeve avulsion," and "anterior labroligamentous periosteal sleeve avulsion" lesion. Duplicate articles and those that did not meet the inclusion criteria were excluded, resulting in the identification of 42 relevant articles. Their references were analyzed for further data curation.

Results

This scoping review demonstrated that ALPSA lesions are difficult to clinically identify. Magnetic resonance angiography in the adduction internal rotation position is the most sensitive and specific imaging modality for identification. Optimal views are the anterosuperior portal for accurate identification and the anteroinferior portal for surgical repair during arthroscopy. Treatment begins with correctly identifying the labrum, in contradistinction to dense reactive fibrous tissue, and reattaching the labrum to the correct anatomic glenoid footprint. Chronic lesions with bone loss require either bone block or soft tissue augmentation procedures.

Conclusion

There is paucity of exclusive literature on ALPSA lesions. It is important to distinguish this lesion from the Bankart lesion as it is associated with worse outcomes. The higher failure rates of ALPSA lesion repair indicate that the current repair techniques require further refinement to improve the outcomes to the standard of Bankart lesions.

Radiographic and Advanced Imaging Evaluation of Posterior Shoulder Instability

PURPOSE OF REVIEW

Posterior shoulder instability is an uncommon but important cause of shoulder dysfunction and pain which may occur as the result of seizure, high energy trauma, or repetitive stress related to occupational or sport-specific activities. This current review details the imaging approach to the patient with posterior shoulder instability and describes commonly associated soft tissue and bony pathologies identified by radiographs, CT, and MR imaging.

RECENT FINDINGS

Advances in MR imaging technology and techniques allow for more accurate evaluation of bone and soft tissue pathology associated with posterior shoulder instability while sparing patients exposure to radiation. Imaging can contribute significantly to the clinical management of patients with posterior shoulder instability by demonstrating the extent of associated injuries and identifying predisposing anatomic conditions. Radiologic evaluation should be guided by clinical history and physical examination, beginning with radiographs followed by CT and/or MRI for assessment of osseous and soft tissue pathology. Synthesis of a patient's clinical history, physical exam findings, and radiologic examinations should guide clinical management.

A novel method for determining the X-ray beam angulation of the supraspinatus outlet view

BACKGROUND

Rapid and accurate quantification of the supraspinatus outlet view (SOV) is a clinical challenge.

PURPOSE

To quantify the X-ray beam angle of the SOV using the horizontal angle of the subscapular spine line (SSSL) and to further verify the feasibility of this method.

MATERIAL AND METHODS

A total of 119 patients who underwent shoulder computed tomography (CT) examination were enrolled in the retrospective study. Three-dimensional (3D) CT reconstruction was performed and manually adjusted to provide the position similar to SOV. The rotation angle of the 3D image along the long axis of the human body (marked as β) was obtained. The horizontal angle of SSSL (marked as α) was measured on the anteroposterior localizer image of shoulder CT. Pearson correlation and linear regression correlation analysis were performed. In addition, the first-time success rate between the experience-based group and the measurement-based group were compared to verify the novel method.

RESULTS

We found a linear correlation between α and β (r = 0.962; P = 0.000). There was no significant correlation between the experience-based group and the measurement-based group in terms of age (P = 0.500), sex (P = 0.397), and side (P = 0.710), but there was a significant statistical difference in the first success rate between the two validation groups (χ² = 5.808^a, P = 0.016).

CONCLUSION

This novel quantitative measurement method for determining the X-ray beam angle of SOV using the horizontal angle of SSSL is feasible.

Posterior shoulder labrocapsular structures in all aspects; 3D volumetric MR arthrography study

Pathologies of the posterior labrocapsular structures of the shoulder joint are far less common than anterior labrocapsuloligamentous lesions. Most of these pathologies have been associated with traumatic posterior dislocation. A smaller portion of the lesions include posterior extension of superior labral anteroposterior lesions, posterior superior internal impingement, and damage to the posterior band of the inferior glenohumeral ligament. Labrocapsular anatomic variations of the posterior shoulder joint can mimic labral pathology on conventional MR and occasionally on MR arthrographic images. Knowledge of this variant anatomy is key to interpreting MR images and studying MR arthrography of the posterior labrocapsular structure to avoid misdiagnosis and unnecessary surgical procedures. In this article, we review normal and variant anatomy of the posterior labrocapsular structure of the shoulder joint based on MR arthrography and discuss how to discriminate normal anatomic variants from labrocapsular damage.

Tennis overuse injuries in the upper extremity

OBJECTIVE

Tennis is a popular sport with high levels of participation. This article aims to describe how upper extremity overuse injuries occur in relation to tennis biomechanics and to review their imaging characteristics and implications for management. In particular, we will review the imaging patterns of internal impingement, scapular dyskinesis, lateral and medial epicondylitis, ulnar collateral ligament insufficiency, valgus extension overload, capitellar osteochondritis dissecans, extensor carpi ulnaris tendinosis and instability, tenosynovitis, triangular fibrocartilage complex injuries, and carpal stress injuries.

CONCLUSION

Tennis is a complex and physically demanding sport with a wide range of associated injuries. Repetitive overloading commonly leads to injuries of the upper extremity. An understanding of the underlying mechanisms of injury and knowledge of these injury patterns will aid the radiologist in generating the correct diagnosis in both the professional and recreational tennis athlete.

A guideline for screw fixation of coracoid process base fracture by 3D simulation

BACKGROUND

Fractures of the base of the coracoid process are relatively rare, but an increasing number of studies have reported using screws to fix coracoid process base fractures. This study was performed to simulate the surgical procedure and obtain the ideal diameter, length, insertion point and angle of the screw from a 3-D axial perspective in Chinese patients.

METHODS

We randomly collected right scapula computed tomography (CT) scans from 100 adults. DICOM-formatted CT scan images were imported into Mimics software. A 3D digital model of the right scapula was established. Two virtual cylinders representing two screws were placed from the top of the coracoid process to the neck of the scapula and across the base of the coracoid process to fix the base of the coracoid process. The largest secure diameters and lengths of the virtual screws were measured. The positions of the insertion points and the directions of the screws were also examined.

RESULTS

The screw insertion safe zone can exhibit an irregular fusiform shape according to the reconstructed scapula model. The mean maximum diameters of the medial and lateral screws were 7.08 ± 1.19 mm and 7.34 ± 1.11 mm, respectively. The mean maximum lengths of the medial and lateral screws were 43.11 ± 6.31 mm and 48.16 ± 6.94 mm, respectively. A screw insertion corridor with a diameter of at least 4.5 mm was found in all patients. We found sex-dependent differences in the mean maximum diameters and maximum lengths of the two screws. The positions of the two insertion points were statistically different across sexes.

CONCLUSIONS

The study provides a valuable guideline for determining the largest secure corridor for two screws in fixing a fracture at the base of the coracoid process. For ideal screw placement, we suggest individualised preoperative 3D reconstruction simulations. Further biomechanical studies are needed to verify the function of the screws.

Sonoarthrographic examination of posterior labrocapsular structures of the shoulder joint

OBJECTIVE

To describe the posterior labral lesions and labrocapsular abnormalities of the shoulder on sonoarthrography and to compare these findings with MR arthrography results.

METHODS

82 shoulders were initially evaluated with ultrasonography and MRI and then were examined with sonoarthrography and MR arthrography following intraarticular injection of diluted gadolinium solution. The ultrasonography images were prospectively evaluated for the presence of posterior labral tear, sublabral cleft, and posterior capsular abnormalities by two radiologists. The diagnostic accuracy of sonoarthrography in the detection of posterior labral tears and posterior labrocapsular variants was compared with that of MR arthrography.

RESULTS

In sonoarthrographic examinations of 82 shoulders, 5 and 6 posterior labral tears were identified by Observer 1 and 2, respectively. Moreover, 6 and 7 posterior sublabral clefts, and 2 and 3 posterior synovial folds were identified by Observer 1 and 2, respectively. All the 82 patients were examined with MR arthrography; however, only 14 patients underwent arthroscopic examination. No significant difference was found among the 82 patients with regard to age, gender, and the prevalence of posterior labral tear, posterior labral cleft, and posterior synovial fold (p > 0.05). Interobserver variability showed substantial agreement between the sonoarthrographic and MR arthrographic results of the posterior labrocapsular structures (κ = 0.71, p < 0.05).

CONCLUSION

Posterior labral tears and posterior synovial folds of the shoulder joint can be evaluated non-invasively by sonoarthrography.

ADVANCES IN KNOWLEDGE

Variations and pathologies of posterior labrocapsular structures of the glenohumeral joint are relatively uncommon.Direct (MR) arthrography is the gold-standard imaging modality to evaluate of posterior labrocapsular abnormalities of the glenohumeral joint.Sonoarthrography of the glenohumeral joint may be utilized in clinical practice in patients with contraindications to (MRI).

Coracoid stress fracture in an elite fast bowler: description of a technique for CT-guided percutaneous screw fixation of coracoid fractures

Coracoid stress fractures are a rare sports injury but present a management challenge, with the focus on optimising return-to-play, whilst minimising complications. Potential contributing mechanisms for the injury are briefly discussed and a novel approach to accurate fracture fixation under CT guidance is described. The ability of radiologists to orient themselves in 3D with a volume dataset on a workstation provides an image-guided option for percutaneous fixation that minimises risk of complications.

Differences in Coracoid and Glenoid Dimensions Based on Sex, Race, and Age: Implications for Use of the Latarjet Technique in Glenoid Reconstruction

BACKGROUND

The Latarjet procedure restores shoulder stability through reconstruction of the glenoid arc. Prior investigations of glenoid and coracoid dimensions have been underpowered to detect differences based on sex and race.

QUESTIONS/PURPOSES

We sought to establish normative values for glenoid width and coracoid dimensions based on sex, race, and age. In addition, we assessed the restoration of glenoid dimensions using the classic and modified Latarjet techniques (classic technique: placing lateral surface of the coracoid to the glenoid; modified technique: placing inferior surface of the coracoid to the glenoid).

METHODS

A total of 993 cadaveric specimens (n = 1986 scapulae) from people over 18 years of age at the time of death were analyzed. Measurements of maximal glenoid width, coracoid width, thickness, and length were recorded. Statistical analysis was performed to detect differences based on sex and race, while univariable linear regression was used to determine the association of increasing age on measured dimensions.

RESULTS

All dimensions of specimens were significantly larger in males than in females. Caucasians possessed larger mean glenoid width, coracoid width, and coracoid length, while coracoid thickness was significantly larger in African Americans. Linear regression analysis found that increasing age was associated with increased glenoid width and coracoid dimensions. Coracoid positioning restored glenoid width in defects measuring 20% of glenoid width using both classic and modified Latarjet techniques, while defects measuring up to 25% were more accurately reproduced using the modified technique.

CONCLUSION

Dimensions were significantly larger in males and in Caucasians, aside from coracoid thickness. Mean dimensions increased with advancing age. Coracoid positioning using classic or modified Latarjet techniques restored glenoid width defects measuring 20% of the glenoid width, while the modified technique allowed for restoration of larger defects.

Multimodality imaging of subacromial impingement syndrome

Subacromial impingement syndrome results from irritation of the tendons of the rotator cuff muscles in the subacromial space and may manifest as a range of pathologies. However, subacromial impingement is a dynamic condition for which imaging reveals predisposing factors but no pathognomonic indicators. Also, the usual imaging features of subacromial impingement may be seen in symptomatic and asymptomatic patients. Therefore, imaging is able to detect tears and describe the risk factors of impingement but cannot confirm subacromial impingement. Radiographs allow assessment of the morphology of the acromion and its lateral extension by means of the acromial index and the critical shoulder angle, which may increase in cases of subacromial impingement. Ultrasound is necessary to evaluate a tendon tear and is the only tool that provides dynamic information, which is essential to assessing dynamic conditions. Magnetic resonance imaging (MRI) allows the assessment of associated intraarticular abnormalities, joint effusion, and bone marrow edema. The objective of this article is to provide an overview of the pathophysiology and clinical manifestations of subacromial impingement and discuss recent advances in the imaging of subacromial impingement and the role of radiography, ultrasound, and MRI in differentiating normal from pathologic findings.

Pathologies of the shoulder and elbow affecting the overhead throwing athlete

The overhead-throwing athlete is susceptible to a variety of predictable disease entities affecting the shoulder and elbow. While the pathophysiology and nomenclature of these diseases are ubiquitous throughout the clinical literature, this information is sparse within the radiology domain. We provide a comprehensive review of these unique injuries with accompanying imaging features in an effort to enhance the role of the radiologist during the management of the overhead thrower. When appropriately recognized and described, the imaging features aid in establishing a diagnosis and ultimately the implementation of appropriate clinical management.