» In this review, we describe the history of the Critical Shoulder Angle (CSA), the utility of the CSA in identifying rotator cuff tears and glenohumeral osteoarthritis, and the association between the CSA and patient-reported outcomes. Additionally, we address some of the controversies surrounding the CSA with an updated literature review. » The CSA is the angle between the plane of the glenoid fossa (the line from the inferior edge of the glenoid to the superior edge of the glenoid) and a line drawn from the inferior edge of the glenoid to the lateral edge of the acromion on a true anteroposterior (Grashey) shoulder radiograph. » An increased CSA (.35°) is thought to alter deltoid vectors, which results in increased superior shear forces on the rotator cuff muscles. This increased loading of the rotator cuff may be a risk factor for the development of rotator cuff tears. » A decreased CSA (,30°) is associated with glenohumeral arthritis due to the increased compressive forces across the glenohumeral joint. » Reports in the literature have both supported and refuted the associations between the CSA, shoulder disease, and clinical treatment outcomes. These conflicting findings may be attributable to the lack of standardized radiographic methods for measuring CSA and/or to measurement errors. » Prospective longitudinal cohort studies involving a standard and reproducible method of CSA measurement are needed to elucidate the true relationship between the CSA and shoulder disease. Disclosure: No external funding was used for this study. On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, one or more of the authors checked "yes" to indicate that the author had a relevant financial relationship in the biomedical arena outside the submitted work and "yes" to indicate that the author had other relationships or activities that could be perceived to influence, or have the potential to influence, what was written in this work (http://links.lww.com/JBJSREV/A359).

The differential diagnoses for spinal cord lesions include spinal tumors and inflammatory processes. The distinction between these pathologies can be difficult if solely based on imaging. We report for the first time to our knowledge a case of idiopathic transverse myelitis (ITM) mimicking a discrete cervical spinal lesion in a 66-year-old man who presented with gait instability and neck pain. The patient's symptoms failed to resolve after an initial course of steroid therapy. Surgical biopsy confirmed the diagnosis of ITM. Subsequent treatment with dexamethasone resulted in complete resolution of the symptoms as well as the intramedullary enhancement. ITM is most common in the cervical and thoracic spine, spanning 3-4 spinal segments. It usually occupies more than 50% of the cross-sectional area of the spinal cord and tends to be central, uniform, and symmetric. It exhibits patchy and peripheral contrast enhancement. These criteria are useful guidelines that help distinguish ITM from neoplastic spinal lesions. A decision to perform biopsy must take into consideration the patient's clinical symptoms, the rate of progression of neurological deficits, and the imaging characteristics of the lesion. Surgical biopsy for questionable lesions should be reserved for patients with progressive neurological deficits refractory to empirical medical therapy.

Trapezius paralysis following injury to the spinal accessory nerve can be a debilitating complication resulting from lymph node biopsy, radical neck dissection, or penetrating trauma in the region of the posterior cervical triangle. Disruption of the delicate muscular balance in the shoulder girdle may result in lateral scapular winging, ipsilateral upper extremity radiculopathy, and limited shoulder function and range of motion. Spontaneous recovery with nonoperative management is possible in some patients, and restoration of function after reparative neural procedures has been observed in patients undergoing timely repair. However, extended delays from the time of injury to surgery are common and may necessitate various muscle transfers to reestablish the complex biomechanics and balance of the shoulder girdle. We describe a modification to the classic Eden-Lange procedure with lateral transfer of the levator scapulae and rhomboid minor to the scapula spine and rhomboid major transfer with a small wafer of bone to the scapula body for chronic lateral winging of the scapula following injury to the spinal accessory nerve as the result of a cervical lymph node biopsy.

Arthroscopic Bankart repair is well documented for having successful outcomes in patients with isolated labral tear involvement with minimal bone loss. Latarjet is a generally accepted procedure in patients with 20-30% glenoid bone loss. When bone loss exceeds that which cannot be managed through Latarjet, a range of options exist and are highly dependent upon the extent of osseous deficiency on both the glenoid and humeral sides, surgeon experience, and patient-specific factors. The use of reverse total shoulder arthroplasty for the management of chronic locked shoulder dislocations has been described as a successful management option. Treatment options for complex anterior shoulder instability range widely based on patients' presenting exam, surgical history, amount of glenoid bone loss, size of Hill-Sachs lesion, and surgeon preference. When selecting the appropriate surgical intervention, the treating surgeon must consider the patient history, physical exam, and preoperative imaging along with patient expectations.

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