Traumatic shoulder injuries: a force mechanism analysis-glenohumeral dislocation and instability

The supine moving apprehension test-Reliability and validity among healthy individuals and patients with anterior shoulder instability

Background

Performance-based tests for patients with anterior shoulder dislocation are lacking. This study determined the reliability and validity of the supine moving apprehension test designed to assess the ability to control anterior instability loads.

Methods

Thirty-six participants were recruited (18 healthy individuals, and 18 patients following anterior shoulder dislocation). Healthy participants performed the supine moving apprehension test on 2 separate occasions to determine test-retest reliability. Patients completed the supine moving apprehension test and the Western Ontario Shoulder Instability index before and 6 months after surgical stabilization of their shoulder. The presence of anterior apprehension was also documented post-operatively.

Results

The supine moving apprehension test demonstrated good test-retest reliability (intraclass correlation coefficient = 0.74-0.84). Patients performed 18-30 repetitions less than healthy individuals during the supine moving apprehension test (P < 0.01). A strong correlation was found between supine moving apprehension test scores and Western Ontario Shoulder Instability post-operatively (r = -0.74, P ≤ 0.01). Supine moving apprehension test scores significantly improved among patients following surgery (P < 0.01). Patients with a negative apprehension test post-operatively performed the supine moving apprehension test significantly better than patients with a positive apprehension test (P < 0.01).

Conclusions

The supine moving apprehension test is reliable and valid among patients with anterior shoulder dislocation and may serve to assess patients' ability to control shoulder anterior instability loads.

Mechanisms of shoulder trauma: Current concepts

Acute traumatic injuries to the glenohumeral articulation are common. The types of injuries depend on age, muscle strength, bone density, and biomechanics of the traumatic event. Understanding the different mechanisms of trauma and how they affect the functional anatomical structures of the shoulder joint is crucial for the treatment of these lesions. Therefore, when clinicians have knowledge of these mechanisms they can accurately diagnose and treat shoulder pathology and predict distinct injury patterns. Here, we have described the fundamentals of the mechanisms of injury of the glenohumeral dislocation, dislocation with fracture of the humeral head, and the proximal humerus fracture. We have focused on common injury mechanisms and the correlation with radiological diagnostics. Radiological and laboratory findings of distinct types of injury were also discussed.

Bilateral Posterior Fracture-Dislocation of the Shoulders Secondary to Uremic Encephalopathy

Bilateral posterior fracture-dislocation of the shoulder is an uncommon injury pattern usually caused by epileptic seizures. The cause of the seizure activity remains unknown in most cases, although the injury has been associated with several conditions. A 59-year-old man with uncontrolled hypertension presented with new-onset generalized tonic-clonic seizures. He was diagnosed with uremic encephalopathy and bilateral posterior fracture-dislocation of his shoulders. His medical condition required stabilization leading to a delay in definitive surgery and a subsequent poor outcome. This case highlights the previously unknown association between bilateral fracture-dislocation of the shoulders and seizures caused by uremic encephalopathy. In these complex situations with competing clinical priorities, it is important to initiate prompt treatment of the cause in any new-onset seizures, to facilitate expedient surgical management of the orthopaedic injury.

Anterior Shoulder Dislocation With an Ipsilateral Humeral Shaft Fracture: A Case Report

Anterior shoulder dislocation is the most common type of shoulder dislocation but if accompanied by an ipsilateral humeral shaft fracture, it becomes extremely rare. There was no clear approach for dealing with these cases. We would like to present a case of a 17-year-old medically free male who was brought to the emergency department by ambulance after a road traffic accident. The patient was conscious, alert, and oriented. His Glasgow Coma Scale (GCS) was 15/15. He had multiple bruises all over his body with obvious swelling in his right arm with an inability to move the arm. There was tenderness over the right arm but an intact distal neurovascular exanimation. X-ray and CT scan showed anterior shoulder dislocation with an ipsilateral humeral shaft fracture of the right arm. There is no specific approach for such cases. However, open reduction with an intramedullary nail showed good outcomes with fewer postoperative neurovascular complications.

Irreducible Posterior Fracture Dislocation of the Shoulder: A Case Report

Posterior shoulder fracture-dislocation is a rare traumatic entity. Early diagnosis results in the adequate treatment of these lesions and prevents serious complications, such as avascular necrosis. Several therapeutic options have been proposed depending on the size of the humeral defect, duration of the dislocation, age of the patient, associated comorbidities, and functional requirements. For this kind of injury, early open anatomical reduction and stable internal fixation remain the optimum treatment option. Arthroplasty is often the last resort for active young patients, particularly in cases of avascular necrosis, humeral head complex fracture, or undiagnosed posterior shoulder dislocation. Here, we report a case of a complex posterior shoulder fracture-dislocation in a young man, which was treated surgically with open reduction and locked plate osteosynthesis using a deltopectoral approach.

Glenoid Track Width Is Smaller Under Dynamic Conditions: An In Vivo Dual-Fluoroscopy Imaging Study

BACKGROUND

The glenoid track concept has been widely used to assess the risk of instability due to bipolar bone loss. The glenoid track width was commonly used as 83% of the glenoid width to determine if a lesion was on-track or off-track. However, the value was obtained under static conditions, and it may not be able to reflect the actual mechanism of traumatic dislocation during motion.

PURPOSE

To compare the glenoid track width under dynamic and static conditions using a dual-fluoroscopic imaging system.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 40 shoulders of 20 healthy volunteers were examined for both dynamic and static tests within a dual-fluoroscopic imaging system at 5 different arm positions: 30°, 60°, 90°, 120°, and 150° of abduction, keeping the shoulder at 90° of external rotation. The participants performed a fast horizontal arm backswing for dynamic tests while keeping their arm in maximum horizontal extension for static tests. Computed tomography scans were used to create 3-dimensional models of the humerus and scapula for 2-dimensional to 3-dimensional image registration. Magnetic resonance imaging scans were obtained to delineate the medial margin of the rotator cuff insertion. The glenoid track width was measured as the distance from the anterior rim of the glenoid to the medial margin of the rotator cuff insertion and compared between static and dynamic conditions.

RESULTS

The mean glenoid track widths at 30°, 60°, 90°, 120°, and 150° of abduction were significantly smaller under dynamic conditions (88%, 81%, 72%, 69%, and 68% of the glenoid width) than those under static conditions (101%, 92%, 84%, 78%, and 77% of the glenoid width) (all P < .001). The glenoid track width significantly decreased with the increasing abduction angles in the range of 30° to 120° under static conditions (all P < .003) and 30° to 90° under dynamic conditions (all P < .001).

CONCLUSION

A smaller dynamic-based value should be considered for the glenoid track width when distinguishing on-track/off-track lesions. Clinical evidence is needed to establish the superiority of the dynamic-based value over the static-based value as an indicator for augmentation procedures.

CLINICAL RELEVANCE

Some off-track lesions might be misclassified as on-track lesions when the original commonly used static-based value of 83% is used as the glenoid track width.

Risk factors for fracture-related infection after open reduction and internal fixation of proximal humerus fractures: A multicenter retrospective study of 496 fractures (TRON group study)

INTRODUCTION

One of the complications of the surgical therapy for proximal humerus fractures is fracture-related infection (FRI). This multicenter study aimed to investigate the incidence of FRI and clarify the risk factors associated with FRI in patients receiving open reduction and internal fixation for proximal humerus fracture.

MATERIAL AND METHODS

Among 684 patients diagnosed as having proximal humerus fracture and who were treated by surgical therapy in 13 institutions (named TRON group) from 2015 through 2020, 496 patients (men, n = 134, women, n = 362; mean [SD] age, 68.5 [14.5] years; mean [SD] body mass index [BMI], 23.0 [4.4] kg/m²) were included as subjects. Excluded were 188 patients due to less than 12 month's follow-up, patients who underwent osteosynthesis using neither plate nor nail and those with open fracture. We extracted the following as risk factors of FRI: sex, BMI, smoking status, diabetes, glenohumeral fracture dislocation, fracture classification, approach, implant, waiting period, type of anesthesia, operative time and blood loss during surgery. We conducted logistic regression analysis to investigate the risk factors of FRI using these extracted items as explanatory variables and the presence or absence of FRI as the response variable.

RESULT

FRI occurred after surgery for proximal humerus fracture in 9 of the 496 patients (1.8%). The causative organism was methicillin-susceptible Staphylococcus aureus in 4 patients, Pseudomonas aeruginosa in one patient and Enterococcus faecalis in one patient. In the other 3 patients, causative organisms were not detected. The univariate analysis showed significant differences for present of glenohumeral fracture dislocation (p = 0.004). Logistic regression analysis showed glenohumeral fracture dislocation to be the significant explanatory factor for FRI (odds ratio 12.3, p = 0.0375).

CONCLUSION

This study revealed an infection rate following open reduction and internal fixation of proximal humerus fracture of 1.8% (9 patients) and that Staphylococcus was the most frequent causative organism. Glenohumeral fracture dislocation is a significant risk for postoperative FRI.

Chronic non-treated posterior fracture-dislocation of the shoulder

Posterior fracture-dislocations often remain undiagnosed at initial medical attendance. In dislocation, the head of the humerus extends beyond the glenoid to form a zone of impaction, which “fixes” it. The injury is almost unidentifiable in standard frontal X-ray images. Meanwhile, continued fixation of the humerus in the state of posterior dislocation leads to a rapid progression of the traumatic impaction over up to 50% of the articular surface area. The associated damage to the articular lip of the scapula, rupture of the rotator cuff muscles, symptoms of shoulder instability after relocation, and severe pain syndrome require advanced treatments for this type of injury. Here we report a clinical case of anatomical neck fracture of the humerus with displaced consolidation, combined to posterior dislocation. To avoid subacromial impingement, instead of correcting the position of the head, we abandoned the reposition and performed an osteotomy with distal displacement of the greater tubercle of the humerus.

Return to Sport After Shoulder Stabilization Procedures: A Criteria-Based Testing Continuum to Guide Rehabilitation and Inform Return-to-Play Decision Making

The athlete with shoulder instability poses a unique challenge to the sports medicine team. Clinical studies support surgical intervention followed by a phased approach to rehabilitation. In the latter phases, it is important to tailor this program to the individual’s specific athletic needs, which requires ongoing qualitative assessment and objective measurement. Passing a return-to-sport testing battery has been shown to decrease the risk of recurrent instability. What is lacking in the literature is a consensus for how to best measure shoulder performance when the required athletic demands are widely varied by hand dominance, sport played, and playing position. Multiple upper-extremity tests have been described in the literature, but there is no consensus on which tests should be used to direct rehabilitation and to safely return the athlete to unrestricted athletic exposure. Using available evidence, we suggest a framework for return-to-play testing that integrates traditional rehabilitation phases with performance testing and graduated sports exposure.

Level of Evidence

Level V, expert opinion.

Imaging of traumatic shoulder injuries – Understanding the surgeon’s perspective

Imaging plays a key role in the assessment and management of traumatic shoulder injuries, and it is important to understand how the imaging details help guide orthopedic surgeons in determining the role for surgical treatment. Imaging is also crucial in preoperative planning, the longitudinal assessment after surgery and the identification of complications after treatment. This review discusses the mechanisms of injury, key imaging findings, therapeutic options and associated complications for the most common shoulder injuries, tailored to the orthopedic surgeon’s perspective.

Management of Locked Posterior Shoulder Dislocation with Reverse Hill-Sachs Lesions via Anatomical Reconstructions

Objective

To evaluate the outcomes of locked posterior shoulder dislocation with reverse Hill–Sachs lesions in patients treated with anatomical reconstructions.

Methods

Patients who were treated at our institution between January 2016 and June 2020 were retrospectively reviewed. The demographics of the patients including gender, age, occupation, and dominant arm were recorded. Eleven cases from 10 patients qualified in this study. Nine males and one female were included. The mean age of the patients was 44.8 years (range, 33–54 years). Mechanism of injury, duration between injuries and definitive diagnosis, misdiagnosis, size of humeral head impaction, treatment maneuver, and details of operation performed were reviewed. Plain radiographs and computed tomography (CT) scan were taken to determine the size of defects preoperatively and fracture healing during follow‐up. During surgery, the deltopectoral approach was employed. Anatomical reconstruction procedure including reduction, disimpaction, bone grafting, and fixation were sequentially performed. Either cancellous autograft from iliac crest or allograft were used and the fractures were anatomically reduced and stabilized by screws or plates. Visual Analog Scale (VAS) and Constant–Murley score were recorded to determine the functional outcomes preoperatively, at 3 months and 6 months postoperatively, and at the last follow‐up. The range of motion in forward flexion was recorded at 6 months follow‐up postoperatively.

Results

Causes of injuries included epileptic seizure in four cases, fall in three cases, and road traffic accident in three cases. Misdiagnoses occurred in five out of 10 patients. The mean time between injury and definitive treatment among those misdiagnosed was 112 days. The mean size of the impacted reverse Hill–Sachs lesions was 33.95% (range, 19.1%–42.6%). All patients received surgical management with anatomical reconstruction approach, including open reduction, disimpaction, bone grafting, and internal fixation. The mean amount of bleeding during operation was 450 mL. The mean follow‐up period was 22.6 months. Fracture healing was observed by 8 weeks in all cases postoperatively and evidence of bone grafting could not be further detected on CT scan at 6 month during follow‐up. VAS was significantly lower at the last follow‐up (0.68 ± 0.21) in comparison to preoperative scores (4.96 ± 0.97) (P < 0.05). Constant–Murley was improved significantly at the last follow‐up (91.7 ± 8.3) in comparison to that preoperatively (40.6 ± 10.3) (P < 0.05). The mean range of motion in forward flexion was 38.25° ± 9.36° preoperatively and significantly improved to 162.48° ± 12.68° at 6‐month follow‐up (P < 0.05).

Conclusion

The anatomical reconstruction procedure by open reduction and bone augmentation for the treatment of locked posterior shoulder dislocation with reverse Hill–Sachs lesion was promising in both fracture healing and functional outcomes.

A Case Report of the Reconstruction of a Bone Defect Following Resection of a Comminuted Fracture of the Lateral Clavicle Using a Titanium Prosthesis

Introduction: This case report describes the reconstruction of a severe comminuted fracture and bone defect in the lateral half of the clavicle using a novel titanium prosthesis. This unique prosthesis has been specifically designed and three dimensionally printed for the clavicle, as opposed to the Oklahoma cemented composite prosthesis used in common practice. The aims of this study were to: (1) describe the prosthesis, its stress analysis, and its surgical fixation and (2) to demonstrate the results of the 2-year follow-up of the patient with the lateral clavicle prosthesis.

Patient's Main Concerns: A 20-year-old, right-handed woman complaining of severe pain in the right shoulder was admitted to our hospital following a traffic accident. Physical examination revealed pain, swelling, tenderness, limb weakness, asymmetric posturing, and loss of function in the right shoulder.

Diagnosis, Intervention, and Outcomes: Radiographic evaluation in the emergency room showed complete destruction with a comminuted fracture of the lateral half of the right clavicle and a comminuted fracture of the coracoid. We designed a new prosthesis for the lateral half of the clavicle, which was then tested by finite element analysis and implanted. Use of the new prosthesis was effective in the reconstruction of the comminuted fracture in the lateral half of the clavicle. After 2 years of follow-up, the patient had an aesthetically acceptable curve and was able to perform her activities of daily living. Her pain was relieved, and the disabilities of the arm, shoulder, and hand score improved. Active range of motion of the shoulder joint and muscle strength were also improved.

Conclusion: This novel prosthesis is recommended for reconstruction of the lateral half of the clavicle following development of bony defects due to fracture. Our patient achieved functional and aesthetic satisfaction with this prosthesis.

The Original Mini-Open Technique for Repair of Humeral Avulsion of the Glenohumeral Ligament

Anterior shoulder dislocations commonly occur in the young, athletic population. The mechanism of dislocation occurs when the shoulder is placed in an abducted, externally rotated position while a forceful anterior moment is applied to the humerus. This position, combined with the force applied, results in an anterior and inferiorly directed dislocation of the humeral head away from the glenoid. Due to the limited stretching capacity of the glenohumeral capsule and associated glenohumeral ligaments, the force of the traumatic dislocation overcomes the tensile strength of these ligaments, resulting in a tear. Although the injury more commonly results in an avulsion of the anteroinferior capsulolabral complex from the glenoid, called a Bankart lesion, other injuries have been described. The anterior inferior glenohumeral ligaments (aIGHLs), may be torn from their humeral attachment, which is referred to as a humeral avulsion of the glenohumeral ligament (HAGL). Although other structures may be injured, the topic of this surgical technique focuses on a mini-open approach for repair of the HAGL lesion.

Chronic posterior fracture-dislocation of the shoulder: case report and a literature review

Posterior shoulder fracture-dislocation is a rare injury accounting for approximately 0.9% of shoulder fracture-dislocations and often misdiagnosed during the initial presentation to a physician. Though the reverse Hill-Sachs lesion is a common injury associated with posterior shoulder dislocation, the associated scapula fracture represents only 6% of the lesions associated with a posterior dislocation of the shoulder. We report the case of a neglected posterior shoulder dislocation with a reverse Hill-Sachs lesion treated by filling with an autologous graft associated with an extra articular fracture of the scapula fixed by a plate and a posterior bone end-stop because of the posterior instability. After two years of follow-up, the patient has no episode of dislocation and is satisfied with the functional result with a constant score of 68/100 points.

Imaging of Acute Shoulder Trauma

Acute injuries to the shoulder girdle are common and frequently encountered by the practicing radiologist. The type of injury is highly dependent on the age of the patient and mechanism of trauma with injuries occurring at the site of greatest mechanical weakness. In this review, we discuss the main clinical features and key imaging findings for the most common shoulder injuries. For each injury, we also provide a section on the important features that the orthopedic surgeon needs to know in order to guide surgical versus nonsurgical management.

The Natural History of Pediatric and Adolescent Shoulder Dislocation

BACKGROUND

Twenty percent of shoulder dislocations occur in people younger than 20 years old. Management of anterior shoulder instability in young patients remains an evolving and controversial topic. Herein we review the natural history of anterior shoulder dislocation in young patients.

METHODS

The English-language literature was searched for studies examining the natural history of pediatric and adolescent shoulder dislocation. Recurrent dislocation was the primary outcome of interest in most studies.

RESULTS

Most studies found that recurrent instability was likely in young patients. Several systematic reviews reported the recurrence rate for young patients to be >70%. Recurrent instability was likely to cause greater damage to the joint and may result in more extensive and costly surgery.

CONCLUSIONS

Most studies agree that recurrent anterior shoulder instability is likely in young patients. Some authors advocate for consideration of early surgery in this high-risk population.

Current Approach to the Diagnosis and Management of Shoulder Dislocation in Children

Shoulder dislocations are a common presentation to the emergency department. Although many cases may be diagnosed by history and clinical examination alone, imaging may help diagnose more challenging cases. Three-view radiographs are important for identifying subtle posterior dislocations, and ultrasonography has been gaining evidence as an alternate diagnostic modality. Intra-articular lidocaine and nerve blocks may improve pain control and reduce the need for procedural sedation. Multiple, evidence-based reduction techniques are described including tips for improving success. Immobilization strategies and follow-up are also discussed.

The glenoid track: a review of the clinical relevance, method of calculation and current evidence behind this method

In the setting of bipolar bone injury, orthopedic surgeons are currently making use of the glenoid track method to guide surgical management. Using preoperative CT or MR imaging, this method allows the identification of patients who are more likely to fail a primary capsuloligamentous Bankart repair. As the glenoid track method becomes increasingly used in preoperative planning, it is important for the radiologist to become familiar with its concept and method of calculation. This review article aims to concisely summarize the current literature and the clinical implications of the glenoid track method.

MR-arthrography and CT-arthrography in sports-related glenolabral injuries: a matched descriptive illustration

The combination of a large range of motion and insufficient bony stabilization makes the glenohumeral joint susceptible to injuries including dislocation in young athletes. Magnetic resonance arthrography (MR-arthrography) and computed tomography arthrography (CT-arthrography) play an important role in the preoperative workup of labroligametous injuries. This paper illustrates MR-arthrography and CT-arthrography findings acquired at the same time on the same subjects to illustrate common causes and sequelae of shoulder instability. Teaching Points • MR-arthrography and CT-arthrography are equivalent for SLAP and full-thickness rotator cuff tears.• CT-arthrography is superior in evaluating osseous defects and cartilage surface lesions.• MR-arthrography is superior in evaluating intrasubstance and extra-articular tendinous injuries.

[Systematics of shoulder instability]

Shoulder instability is defined as a symptomatic abnormal motion of the humeral head relative to the glenoid during active shoulder motion. Glenohumeral instabilities are classified according to the causative factors as the pathogenesis of instability plays an important role with respect to treatment options. Instabilities are classified into traumatic and atraumatic instabilities as part of a multidirectional instability syndrome and into microtraumatic instabilities.For diagnostics plain radiographs ("trauma series") are performed to document shoulder dislocation and its successful repositioning. Direct magnetic resonance (MR) arthrography is the most important imaging modality for delineation of the different injury patterns of the labral-ligamentous complex and bony structures. Monocontrast computed tomography (CT) arthrography with the use of multidetector CT scanners represents an alternative imaging modality; however, MR imaging should be preferred in the work-up of shoulder instabilities due to the mostly younger age of patients.

Irreducible superolateral dislocation of the glenohumeral joint

The overwhelming majority of glenohumeral dislocations are anterior dislocations that either spontaneously reduce or are reduced at the point of care without significant complications. Posterior dislocations are uncommon, and superior and inferior dislocations are even rarer. We present a case of "superolateral" shoulder dislocation in which the entire rotator cuff was torn either off its insertion or at the musculotendinous junction in combination with a large longitudinal split tear of the deltoid muscle. This allowed the humeral head to dislocate both superiorly and laterally into a subcutaneous position through the tear of the anterolateral deltoid muscle with an associated de-gloving soft tissue lesion. Buttonholing of the humeral head through the deltoid and interposition of the dislocated long head of the biceps tendon and macerated rotator cuff prevented closed reduction of the glenohumeral joint. The resultant radiographic appearance and treatment of this dislocation is unique. To our knowledge, this is the first reported case of this dislocation in the literature.

What's in a name? Upper extremity fracture eponyms (Part 1)

Eponymous extremity fractures are commonly encountered in the emergency setting. Correct eponym usage allows rapid, succinct communication of complex injuries. We will review both common and less frequently encountered extremity fracture eponyms, focusing on imaging features to identify and differentiate these injuries. We focus on plain radiographic findings, with supporting computed tomography (CT) images. For each injury, important radiologic descriptors are discussed which may need to be communicated to consultants. Aspects of management and follow-up imaging recommendations are included. This is a two-part review: Part 1 focuses on fracture eponyms of the upper extremity, while Part 2 covers fracture eponyms of the lower extremity.

Bony humeral avulsion of the glenohumeral ligament

A 51-year-old man sustained an anterior shoulder dislocation during a motor vehicle accident. Radiographs and noncontrast magnetic images were obtained. resonance images were obtained.