Acute Versus Delayed Magnetic Resonance Imaging and Associated Abnormalities in Traumatic Anterior Shoulder Dislocations

Clinical and radiographic outcomes of primary vs. revision arthroscopic anatomic glenoid reconstruction with distal tibial allograft for anterior shoulder instability with bone loss

BACKGROUND

The purpose of this study was to assess the clinical and radiographic outcomes of arthroscopic anatomic glenoid reconstruction (AAGR) used for primary vs. revision surgery for addressing anterior shoulder instability with bone loss.

METHODS

We performed a retrospective review on consecutive patients who underwent AAGR from 2012 to 2020. Patients who received AAGR for anterior shoulder instability with bone loss and had a minimum follow-up of 2 years were included. Exclusion criteria included patients with incomplete primary patient-reported outcome scores (PROs), multidirectional instability, glenoid fracture, nonrigid fixation and concomitant humeral avulsion of the glenohumeral ligament, or rotator cuff repair. Our primary outcome was measured using the Western Ontario Shoulder Instability Index (WOSI) scores. Secondary outcomes included postoperative Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH) scores, complications, recurrence of instability and computed tomographic (CT) evaluation of graft position, resorption, and healing.

RESULTS

There were 73 patients (52 primary and 21 revision) finally included. Both groups had comparable demographics and preoperative WOSI and DASH scores. The primary group had significantly better postoperative WOSI and DASH scores at final follow-up when compared to the revision group (WOSI: 21.0 vs. 33.8, P = .019; DASH: 7.3 vs. 17.2, P = .001). The primary group also showed significantly better WOSI scores than the revision group at the 6-month, 1-year, and 2-year time points (P = .029, .022, and .003, respectively). The overall complication rate was 9.6% (5 of 52) in the primary group and 23.8% (5 of 21) in the revision group. Both groups showed good graft healing and placement in the anterior-to-posterior and mediolateral orientation and had a similar rate of graft resorption and remodeling. There was no difference between the groups in the remainder of the CT measurements.

CONCLUSION

Functional outcome scores and stiffness were significantly worse in patients undergoing an AAGR procedure after a failed instability surgery when compared with patients undergoing primary AAGR. There were no differences in postoperative recurrence of instability or radiographic outcomes. As a result, AAGR should be considered as a primary treatment option within current treatment algorithms for shoulder instability.

Serial Magnetic Resonance Arthrography for a Midsubstance Capsular Tear in a Patient With Traumatic Anterior Shoulder Instability

The natural history of midsubstance capsular tears (MCTs) is unclear. We herein describe a case of MCT observed using serial magnetic resonance (MR) arthrography. A 46-year-old woman presented with excessive external rotation of the left glenohumeral joint, resulting in an initial anterior dislocation of the left shoulder. She subsequently developed recurrent shoulder joint dislocations. MR arthrography revealed an MCT without a Bankart lesion three months after the initial dislocation. She opted for nonoperative treatment, but the shoulder instability did not improve. The second MR arthrography, nine months after the initial dislocation, showed no natural healing of the MCT. The third MR arthrography, 12 months after the initial dislocation, also showed no natural healing. Her shoulder instability remained persistent. The patient then decided to have surgery. Arthroscopy revealed a large capsular defect extending from the glenoid to the humeral head in the anterior inferior glenohumeral ligamentous complex. The MCT was repaired with the placement of nonabsorbable sutures in a side-to-side fashion. At the final follow-up, three years postoperatively, the patient had no anterior shoulder instability. The Rowe score was 100 points. MR arthrography showed good repair integrity of the MCT at one year postoperatively. Serial MR arthrography was useful for both the patient and the shoulder surgeon in considering the treatment of the MCT, facilitating an accurate and qualitative assessment of whether natural healing of the MCT had been achieved.

Magnetic Resonance Arthrogram Outperforms Standard Magnetic Resonance Imaging 2 Weeks After First Shoulder Dislocation for Labral Tear Diagnosis

PURPOSE

To determine the comparative accuracy and precision of routine magnetic resonance imaging (MRI) versus magnetic resonance (MR) arthrogram in measuring labral tear size as a function of time from a shoulder dislocation.

METHODS

We retrospectively evaluated consecutive patients who underwent primary arthroscopic stabilization between 2012 and 2021 in a single academic center. All patients completed a preoperative MRI or MR arthrogram of the shoulder within 60 days of injury and subsequently underwent arthroscopic repair within 6 months of imaging. Intraoperative labral tear size and location were used as standards for comparison. Three musculoskeletal radiologists independently interpreted tear extent using a clock-face convention. Accuracy and precision of MR labral tear measurements were defined based on location and size of the tear, respectively. Accuracy and precision were compared between MRI and MR arthrogram as a function of time from dislocation.

RESULTS

In total, 32 MRIs and 65 MR arthrograms (total n = 97) were assessed. Multivariate analysis demonstrated that intraoperative tear size, early imaging, and arthrogram status were associated with increased MR accuracy and precision (P < .05). Ordering surgeons preferred arthrogram for delayed imaging (P = .018). For routine MRI, error in accuracy increased by 3.4° per day and error in precision increased by 2.3° per day (P < .001) from time of injury. MR arthrogram, however, was not temporally influenced. Significant loss of accuracy and precision of MRI compared with MR arthrogram occurred at 2 weeks after an acute shoulder dislocation.

CONCLUSIONS

Compared with MR arthrogram, conventional MRI demonstrates time-dependent loss of accuracy and precision in determining shoulder labral tear extent after dislocation, with statistical divergence occurring at 2 weeks.

LEVEL OF EVIDENCE

Level II, retrospective radiographic diagnostic study.

Concomitant Glenohumeral Instability and Rotator Cuff Injury: An Epidemiologic and Case-Control Analysis in Military Cadets

INTRODUCTION

Concomitant rotator cuff tear and glenohumeral instability in a large cohort of young and active patients has not been examined. The purpose of this study was to investigate the incidence, associated variables, and outcomes in military cadets undergoing shoulder stabilization procedures with these concomitant pathologies.

METHODS

A retrospective cohort study of a consecutive series of collegiate patients who underwent shoulder stabilization from 2014 to 2018 at a single service academy was conducted. Exclusion criteria were noncadets, revision instability cases, multidirectional instability, and prior rotator cuff repair. A nested case-control analysis was done in a matched series of patients with and without MRI evidence of rotator cuff tear. Baseline demographics, VAS pain scale, physical therapy duration, and time to surgery were analyzed. Postoperative metrics included rate of recurrent instability, subjective outcomes, VAS pain scale, and military-specific criteria.

RESULTS

Three hundred twenty-four cadets met the inclusion criteria, including 272 men and 52 women averaging 20.53 ± 1.80 years of age. MRI demonstrated concomitant rotator cuff tears in 5.56% of cases. A matched case-control comparison between patients with (rotator cuff tear group) and without (no rotator cuff tear group) rotator cuff tear showed no differences in preoperative data, recurrent instability rate, or postoperative VAS pain scores (0.24 versus 0.88, P = 0.207) at mean 44-month follow-up. Fifteen of 17 patients (88.2%) in each group returned to full activity (P > 0.999). No patients failed to graduate due to shoulder concerns. No patients in the rotator cuff tear group underwent a medical board for separation from the military compared with 2 (11.8%) in the no rotator cuff tear group (P = 0.163).

CONCLUSIONS

The incidence of concomitant rotator cuff tears in this study of military cadets undergoing shoulder stabilization was 5.56%. In a matched cohort comparison, the presence of a rotator cuff tear on preoperative MRI was not associated with inferior clinical outcomes.

Shoulder Lesions Do Not Increase Inflammatory Biomarkers in Patients Undergoing Surgery for Glenohumeral Instability: An Exploratory Study

Circulating protein biomarkers have demonstrated utility as a diagnostic tool in predicting musculoskeletal disease severity, but their utility in the evaluation of shoulder lesions associated with shoulder instability is unknown. Thus, the purpose of this exploratory study was to determine whether preoperative biomarkers of cartilage turnover and inflammation are associated with specific shoulder lesions in shoulder instability. Thirty-three patients (29.9 ± 9.4 years of age, 4.5 ± 4.7 dislocations) undergoing surgical treatment for shoulder instability were assessed for the presence or absence of associated shoulder lesions. Biomarkers including cartilage oligomeric matrix protein (COMP), C-reactive protein (HS-CRP), interleukin-8 (IL-8), and macrophage inflammatory protein-1β (MIP-1b) were collected at the time of surgery. Patients with Hill-Sachs lesions had a 31% increase in COMP plasma levels (p=0.046). No other significant differences were observed for COMP, HS-CRP, IL-8, and MIP-1b with any shoulder lesion including Hill-Sachs lesions, capsular injuries, bony Bankart lesions, and SLAP lesions. In conclusion, inflammatory biomarkers including HS-CRP, IL-8, and MIP-1b were not associated with specific shoulder lesions, while biomarkers of cartilage turnover (COMP) were only elevated in Hill-Sachs lesions. These findings suggest that these biomarkers may have limited utility as prognostic indicators in patients with shoulder instability, though large-scale and longitudinal studies are still necessary.

Magnetic resonance imaging of the shoulder

The aim of this article is to review the use of magnetic resonance imaging (MRI) for the evaluation of shoulder pain, which is a common clinical complaint of the musculoskeletal system. MRI is an essential auxiliary tool to evaluate these patients because of its high resolution and high sensitivity in depicting the soft tissues. This article will review the imaging technique, normal imaging anatomy, and most common imaging findings of disorders of tendons, labrum, and ligaments of the shoulder. It will also discuss common systemic diseases that manifest in the shoulder as well as disorders of the acromioclavicular joint and bursae. New advances and research in MRI have provided additional potential uses for evaluating shoulder derangements.

[Fracture diagnosis: upper extremities : Shoulder and shoulder girdle]

BACKGROUND

The shoulder girdle is a chain of bones and joints which connect the upper extremity to the axial skeleton. The shoulder as a biomechanical unit has a remarkable range of motion and is therefore frequently prone to injuries of the three major joints (sternoclavicular joint, acromioclavicular joint, glenohumeral joint) and the bony elements (clavicle, scapula, humerus). Projection radiography is still the first imaging modality for injuries of the shoulder and usually sufficient for initial diagnosis and injury classification. Computed tomography (including 3D reconstructions) and magnetic resonance imaging provide additional useful information for the detection of accompanying soft-tissue injury, for surgical planning and in cases of complex anatomy (e.g., scapular fractures).

PURPOSE

We aim to describe the fundamentals of injuries of the shoulder girdle and the proximal humerus with special emphasis on radiological diagnostics.

MATERIALS AND METHODS

A selective PubMed literature search was performed using the following terms: "sternoclavicular joint dislocation", "clavicle fracture", "acromioclavicular joint injury", "scapular fracture", "shoulder dislocation", "proximal humerus fracture", and "shoulder girdle injuries".

RESULTS

The article describes the basics of the anatomy, the trauma mechanism and the epidemiology of the most common injuries of the shoulder girdle and the proximal humerus. Special emphasis is given to radiological diagnostics, including basic projection radiography and advanced cross-sectional imaging.

Management of the First-time Traumatic Anterior Shoulder Dislocation

Traumatic anterior dislocation of the shoulder is one of the most common directions of instability following a traumatic event. Although the incidence of shoulder dislocation is similar between young and elderly patients, most studies have traditionally focused on young patients due to relatively high rates of recurrent dislocations in this population. However, shoulder dislocations in older patients also require careful evaluation and treatment selection because they can lead to persistent pain and disability due to rotator cuff tears and nerve injuries. This article provides an overview of the nature and pathology of acute primary anterior shoulder dislocation, widely accepted management modalities, and differences in treatment for young and elderly patients.