Traumatic posterior glenohumeral dislocation: classification, pathoanatomy, diagnosis, and treatment

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.

Irreducible Posterior Shoulder Dislocation With Concomitant Fracture of Both the Greater and Lesser Tuberosity: An Extremely Rare Shoulder Injury

Posterior shoulder dislocation is a relatively rare injury representing only 5% of all shoulder dislocations. It is usually the result of a high-energy trauma or an epileptic seizure. Diagnosis is challenging with half of these injuries missed in the emergency room (ER). Often the dislocation is accompanied by a lesser tuberosity fracture as a result of the impact between the posterior glenoid and the proximal humerus. Additionally, fractures of the greater tuberosity or even the metaphysis are extremely rare, and their treatment remains challenging. We present a rare case of posterior locked shoulder dislocation with a concomitant lesser and greater tuberosity fracture in a young patient. A 29-year-old male was brought to the ER following a motor vehicle accident. The patient reported significant pain and inability to move his left shoulder. The arm was locked in an internal rotation and was neurovascularly intact. Simple radiographs revealed a locked posterior dislocation with fractures of both the lesser and greater tuberosity. The CT scan confirmed the fracture pattern and excluded metaphyseal fracture. Surgical treatment was decided. Under general anesthesia and a classic thoracodeltoid approach, both tuberosities were recognized and the dislocation was gently reduced. Fixation of the tuberosities with an anatomic plate and Ethibond No. 5 sutures was performed. He was discharged the next day with a 30-degree abduction sling cast. He was instructed to perform passive shoulder and scapula exercises once a day. After one month, the sling was removed and active elevation and rotation exercises were started. Plane X-rays were performed at one, six, and twelve months. The reduction remained stable and the patient recovered full range of motion with a slight loss of external rotation (10 degrees) compared to the contralateral limb. He returned to his previous activities without any complications. Posterior shoulder dislocations with additional fractures of the tuberosities are rare and severe injuries requiring open surgery as the humeral head may remain locked prohibiting closed reduction. Even after the reduction, the stable fixation of the tuberosities is crucial for shoulder stability and postoperative clinical and functional results.

Treatment and outcomes of chronic locked posterior shoulder dislocations: a retrospective case series

BACKGROUND

Posterior shoulder dislocations are rare injuries that are often missed on initial presentation. Cases left untreated for more than three weeks are considered chronic, cannot be reduced closely (they become locked) and are usually associated with a significant reverse Hill-Sachs defect. The aim of this study was to evaluate the outcomes of chronic locked posterior shoulder dislocations treated with the McLaughlin procedure (classic or modified).

METHODS

This retrospective study included 12 patients with chronic locked posterior shoulder dislocation operated on between 2000 and 2021 by two surgeons in two institutions. Patients received a thorough clinical examination and radiological assessment before and after surgery. Shoulders were repaired with the McLaughlin or modified McLaughlin procedure. Outcomes were assessed by comparing pre- and postoperative values of clinical variables.

RESULTS

Most of the dislocations were of traumatic origin. The average delay between dislocation and surgical reduction was 13.5 ± 9.7 weeks. Postoperative clinical outcomes were favourable, with an average subjective shoulder value of 86.4 ± 11.1 and a normalized Constant -Murley score of 90 ± 8.3. None of the patients had a recurrence of shoulder dislocation, but one patient developed avascular necrosis of the humeral head and two patients developed glenohumeral osteoarthritis.

CONCLUSIONS

In this group of patients with chronic locked posterior shoulder dislocation, the clinical outcomes of McLaughlin and modified McLaughlin procedures were satisfactory, even when surgery was significantly delayed.

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.

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.

Surgical management of bilateral concomitant posterior fracture-dislocation of the shoulder

We present the case of a 71-year-old man who suffered a bilateral posterior fracture-dislocation of the shoulder after an idiopathic seizure.

After immediate closed reduction, CT-scan images revealed bilateral anterior reverse Hill–Sachs lesion superior to 30 % of the articular humeral head. A surgical treatment was performed for reconstruction of segmental defects of the articular humeral heads followed by filling the defect using lesser tuberosity transposition. Early rehabilitation protocol was prescribed. After 14 months, the patient returned to normal daily activities with no complaint.

Anatomical humeral head reconstruction and bone defect filling resulted in a good clinical outcome after posterior shoulder dislocation. It can be the treatment of choice for large humeral head defects, especially in younger patients with good bone stock.

Modified McLaughlin Procedure Using a Double-Row Suture Anchor for Chronic Locked Posterior Shoulder Dislocation: A Case Report

CASE

A 49-year-old highly active man had a direct fall on the left shoulder, causing a chronic locked posterior shoulder dislocation. Radiographic analysis revealed a reverse Hill-Sachs lesion (RHSL) that affected 31% of the articular surface. He was successfully treated with a modified McLaughlin procedure that included a double-row suture anchor as a novel fixation approach to secure the lesser tuberosity transfer and the subscapularis tenodesis.

CONCLUSION

The reported approach for reconstructing the RHSL provides adequate stability, pain reduction, and functional outcomes. It may be considered as an option for joint preservation in extensive humeral head defects.

Posterior shoulder dislocation with associated reverse Hill-Sachs lesion: clinical outcome 10 years after joint-preserving surgery

INTRODUCTION

Posterior shoulder dislocation in association with reverse Hill-Sachs lesion is a rather rare injury. Few studies reporting results after joint-preserving surgery in these cases are available. This current study presents the clinical outcomes 10 years postoperatively.

MATERIALS AND METHODS

In a prospective case series, we operatively treated 12 consecutive patients (all males) after posterior shoulder dislocation with associated reverse Hill-Sachs lesion using joint-preserving techniques. Patients received surgery in a single center between January 2008 and December 2011. The joint-preserving surgical procedure was chosen depending on the defect size and bone quality. The following outcome-measures were analyzed: Constant-Score, DASH-Score, ROWE-Score, and SF-12. Results 1, 5, and 10 years postoperatively were compared.

RESULTS

Out of 12 patients, ten patients (83.3%) were followed-up with a mean follow-up interval of 10.7 years (range 9.3-12.8). The mean patient age at the time of the last follow-up was 51 years (32-66). The outcome scores at the final follow-up were: Constant 92.5 (range 70.0-100), DASH 3.2 (0.0-10.8), ROWE 91.0 (85.0-100), and SF-12 87.8 (77.5-98.3). Clinical results had improved from 1 to 5 years postoperatively and showed a tendency for even further improvement after 10 years.

CONCLUSIONS

Joint-preserving surgical therapy of posterior shoulder dislocation provides excellent results when the morphology of the reverse Hill-Sachs lesion is respected in surgical decision-making.

TRIAL REGISTRATION

223/2012BO2, 02 August 2010.

Implant-free iliac crest bone graft procedure shows anatomic remodelling without redislocation in recurrent anterior shoulder instability after short-term follow-up

INTRODUCTION

With the help of a J-shaped bicortical iliac crest bone graft, the morphology of the glenoid can be augmented without having to use screws to achieve glenohumeral stability. The aim of this retrospective clinical study was to evaluate the clinical stability and function of the shoulder joint as well as the radiological remodelling process and arthropathic outcomes following the J-bone graft technique.

MATERIALS AND METHODS

34 patients with recurrent shoulder dislocations and bony glenoid defects were treated with the J-bone graft technique between 2010 and 2018 at our level-I trauma centre. 15 patients (18 shoulders) could be recruited for the study. Pain levels, ASES, UCLA, SST, DASH, Rowe and WOSI Scores were collected using questionnaires. In 13 patients (16 shoulders) the Constant Score, ROM, CT with 3D reconstruction of the glenoid to assess the graft remodelling and X-rays were performed additionally.

RESULTS

None of the patients suffered subluxations or recurrent dislocations during the follow-up period. The overall complication rate was 11%. The evaluation using objective and subjective shoulder function scores yielded good-to-excellent results. Radiological assessment at follow-up showed a low rate of moderate-to-severe arthritis (12%) and a high rate of shoulders without any signs of arthritic degeneration (53%). The CT scans all revealed an almost complete restoration of the glenoid with none of the grafts being resorbed. A rise in the average glenoid circumference and glenoid area could be demonstrated between preoperative measurements (81.6 and 82.4%, respectively) and follow-up measurements (104 and 102.5%, respectively).

CONCLUSION

The results of this study show a successful stabilisation of the shoulder joint and a low complication rate following the J-bone graft technique. Remodelling of the bone graft could be demonstrated, which in turn led to an almost perfect glenoid surface area of 100%.

Posterior Shoulder Instability After Infraclavicular Block for Outpatient Hand Surgery

Regional blocks are being increasingly utilized for anesthesia for various orthopedic procedures. Several studies have shown that regional anesthesia has fewer side effects and improved postoperative pain relief compared to general anesthesia, but regional blocks are not without risks. We present case reports of 2 patients who experienced posterior shoulder instability, one of whom had a posterior shoulder dislocation, immediately in the postanesthesia care unit after undergoing hand surgery with regional anesthesia. This paper highlights the importance of being aware that patients might be at increased risk of shoulder instability after upper extremity regional anesthesia, and appropriate perioperative precautions should be taken.

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.

Treatment of chronic locked posterior dislocation of the shoulder with the modified McLaughlin procedure

BACKGROUND

Locked posterior dislocation of the shoulder (LPDS) is a challenging condition for the orthopedic surgeon. The problem with cases of chronic LPDS is that they may result in worse clinical outcomes because the size of the reverse Hill-Sachs lesion and cartilage damage can increase over time. Multiple treatment strategies have been reported in the literature for the treatment of chronic cases. The purpose of this study was to report our experience with the modified McLaughlin technique for the treatment of chronic LPDS and evaluate the mid- and long-term functional outcomes.

METHODS

This was a retrospective single-center study including a consecutive series of 10 patients who underwent the modified McLaughlin procedure for the treatment of chronic LPDS. The time between dislocation and treatment ranged from 6 weeks to 14 months (mean, 20.9 weeks). Postoperative imaging and functional evaluation were performed with a minimum of 2 years' follow-up (range, 24-110 months). Functional outcomes were assessed by means of a visual analog scale score for pain and patient satisfaction regarding the operation, the Constant-Murley score, and the University of California, Los Angeles shoulder rating scale.

RESULTS

The mean follow-up period was 59.4 months (range, 24-110 months). Range of motion improved significantly after surgery: Mean forward flexion improved from 71° ± 5° to 126°± 37° (P < .001), mean external rotation improved from 7°± 7° to 52° ± 18° (P = .012), and mean internal rotation improved from gluteal region ± 1 vertebral level to L1 ± 4 vertebral levels (P = .001). Functional outcome measures demonstrated significant improvements: The mean Constant-Murley score improved from 22 ± 2.4 (range, 20-26) to 65 ± 21.5 (P < .001); the mean University of California, Los Angeles score improved from 9.8 ± 1.3 (range, 8-12) to 27 ± 9.7 (P < .001); and the mean visual analog scale score improved from 4.6 ± 0.8 (range, 3-6) to 2.4 ± 2.3 (P < .001). Of the patients, 8 (80%) were satisfied with the procedure. The 2 remaining cases had a delay from injury to diagnosis > 6 months and evolved with poor functional outcomes and severe glenohumeral degenerative joint disease. There were no cases of recurrent dislocation, infection, or neurologic injury during the follow-up.

CONCLUSION

Our study findings demonstrated that the modified McLaughlin procedure showed good results over a 2-year minimum follow-up period. The clinical outcomes of this procedure are worse when there is a delay from injury to diagnosis > 6 months.

Surgical treatment of the humeral head osteochondral defects in chronic shoulder dislocation: Literature review

Background. The shoulder joint is the one most amenable to dislocation. Dislocation of the humeral head is complicated by combined injuries of the shoulder joint, and if the patient does not seek treatment on the first day after the dislocation, irreversible changes in bone and soft tissue structures are formed.The aim of this review was to analyze modern methods of diagnosis and treatment of patients with defects in the articular surfaces of the scapula and humerus head with chronic shoulder dislocations.Material and methods. To search for literature data, we used the electronic databases MEDLINE, PudMed, eLIBRARY with a selection of sources published from 2000 to 2020. The analysis was carried out on works devoted to the diagnosis, surgical treatment and complications of traumatic shoulder dislocations.Results. When analyzing the literature on the surgical treatment of shoulder dislocations, we did not find clear criteria for planning the extent of surgery. The obtained results of surgical treatment testify to well-studied technologies for treating osteochondral defects of the humeral head up to 25 % of its total area. In the presence of a defect of 50 % of humeral head area or more, satisfactory results are shown when carrying out arthroplasty of the joint using a reverse endoprosthesis. However, the treatment of defects ranging in size from 25 to 50 % is still an unexplored problem. There are single techniques using allografts, mainly in English-speaking countries and, to a lesser extent, on the territory of the Russian Federation. Thus, the search for an algorithm for choosing a surgical treatment based on multi-layer spiral computed tomography and/or magnetic resonance imaging data, and the development of a new method of surgical treatment taking into account the obtained data are priority areas in modern traumatology and orthopedics.

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.

Posterior shoulder dislocation with reverse Hill-Sachs lesion. A technical note and report of two cases

Posterior shoulder dislocation (PSD) with a reverse Hill-Sachs lesion is a rare injury with challenging management. This article is a technical note, describing the combination of both, modified McLaughlin procedure with posterior Bankart repair, for the surgical treatment of traumatic PSD associated with a substantial reverse Hill-Sachs lesion. Two patients with mid-term follow-up are presented. Approaching and repairing both sides of the joint, balance and congruency are restored, the humeral head is centralized in the glenoid and the patient starts early mobilization and rehabilitation safely.

Bilateral neglected posterior dislocation of the shoulder treated by reverse arthroplasty and contralateral osteochondral autograft. A case report

Bilateral posterior dislocation of the glenohumeral joint is an uncommon event, that can be missed at the initial presentation. We report the case of a 76-year old woman, who suffered a traumatic bilateral posterior dislocation, that was diagnosed three months later. She underwent surgical treatment on both shoulders in a single stage. Since the right shoulder showed a defect of the articular surface >50%, a reverse shoulder arthroplasty was performed on this side. The resected portion of the humeral head was retrieved and used as osteochondral graft to fill the reverse Hill-Sachs lesion of the left shoulder.

At 18-month follow up, the patient was pain-free and had recovered excellent shoulder function on both sides: Constant score was 79 for the right shoulder and 88 for the left one. X-rays showed a grade 1 scapular notch of the right reverse prosthesis and good incorporation of the graft in the left shoulder, with no evidence of degenerative joint changes.

Neglected posterior dislocations of the shoulder can be surgically treated by replacement or reconstruction. In case of bilateral injuries, the surgeon should carefully evaluate the pathoanatomy of both glenohumeral joints in order to choose and plan the most suitable procedure. If shoulder replacement is required on one side, the resected portion of the humeral head can be used as osteochondral autograft for a reconstruction procedure in the opposite side. The choice is influenced by several variables and decision-making might be challenging.

Acceptable Long-Term Outcomes of Arthroscopic Bone Grafting for Recurrent Posterior Shoulder Instability: Minimum Follow-Up of 5 Years

PURPOSE

To examine the long-term clinical outcome associated with arthroscopically placed autologous iliac crest bone graft (ICBG) for recurrent posterior shoulder instability.

METHODS

From January 2008 to December 2013, patients treated with posterior ICBG and a minimum follow-up of 5 years were included. Clinical outcome of patients operated with a posterior ICBG was analyzed with multiple patient-reported outcome measures included Constant (CS), American Shoulder and Elbow Surgeons (ASES), Walch-Duplay, and Rowe scores, shoulder subjective value, and pain visual analog score. Patient satisfaction was assessed by asking the patients their overall level of satisfaction at last follow-up on a 1 to 10 scale.

RESULTS

In total, 18 patients (19 shoulders) were included. At a mean follow-up of 7.3 years (range, 5-10 years), patients had significant improvements in their mean CS from 63 (standard deviation [SD] 18) to 80 (SD 18; P = .005), ASES from 57 (SD 18) to 81 (SD 18; P = .003), Walch-Duplay from 34 (SD 31) to 79 (SD 22; P < .001), and Rowe score from 37 (SD 23) to 79 (SD 24; P < .001). Pain level decreased from 5.6 (SD 2.5) preoperative to 2.3 (SD 2.3; P < .001) and shoulder subjective value improved 58 (SD 20) to 76 (SD 24; P = .002). Global satisfaction with the procedure was 8.4 (SD 2.1). Clinical significance was met or exceeded by 84% for CS and 89% of the patients for ASES and 95% met or exceeded satisfaction threshold for CS. There were 7 shoulders (37%) reoperated for symptomatic screw irritation.

CONCLUSIONS

This series reporting on the long-term follow-up after arthroscopic posterior ICBG for recurrent posterior shoulder instability demonstrates, despite a high number of reoperations for symptomatic screw irritation, its effectiveness with acceptable clinical outcomes and satisfied patients.

LEVEL OF EVIDENCE

IV, therapeutic case series.

Multidirectional Shoulder Instability With Circumferential Labral Tear and Bony Reverse Hill Sachs: Treatment with 270° Labral Repair and Fresh Talus Osteochondral Allograft to the Humeral Head

Traumatic posterior dislocations of the shoulder can result in bony defects, labral tears, and cartilage injuries of the glenohumeral joint. Although traditional Hill-Sachs lesions from anterior dislocations are more commonly identified, reverse Hill-Sachs lesions caused by posterior dislocation often leads to recurrent engagement of the humeral head with the glenoid and significantly greater damage to the humeral chondral surface. In severe traumatic cases, concomitant damage of the capsulolabral soft tissues, such as circumferential labral lesions, can lead to chronic shoulder instability and residual glenoid bone loss. These lesions further add to the complexity of managing patients with posterior dislocations of the shoulder because of the challenges of achieving adequate anatomic reduction and tensioning of the capsulolabral junction, while also using a combination of arthroscopic and open-labral repair techniques. In the setting of reverse Hill-Sachs lesions treatment, it is important to address the bony and cartilage defect. The purpose of this Technical Note is to describe our preferred technique for arthroscopic repair of circumferential lesions of the glenoid labrum causing multidirectional instability with concomitant reverse Hill-Sachs Lesion treatment with fresh talus osteochondral allograft.

Posterior shoulder fracture-dislocation: A systematic review of the literature and current aspects of management

PURPOSE

Posterior fracture-dislocation of shoulder is an infrequent traumatic event; however, most orthopaedic surgeons may face the challenge of treating it. The aim of this study is to review and summarise systematically the current principles of the management of this complex injury, and create a treatment algorithm.

METHODS

Both PubMed and Scopus Databases were systematically searched for the terms "posterior shoulder fracture-dislocation" or "posterior glenohumeral fracture-dislocation" or "posterior glenoid fracture-dislocation" for articles written in English and published in the last decade.

RESULTS

A total of 900 articles were identified, of which 13 were retained for analysis. A total of 153 patients (161 shoulders) were identified. These patients were treated either with open reduction and internal fixation, modified McLaughlin procedure, allograft/autograft humeral head reconstruction or shoulder arthroplasty. The mean age was 40.15 years. The mean postoperative Constant score in cases treated by open reduction and internal fixation was 86.45, whereas by bone graft was 84.18. Further, the mean postoperative Constant score was between 79.6 and 67.1 in those that were managed by modified McLaughlin and arthroplasty procedure, respectively.

CONCLUSION

The management of posterior shoulder fracture-dislocation may be challenging, and the best surgical option depends on many variables such as the chronicity of the injury, the presence of a fracture at the level of the surgical neck or tuberosities and the extend of the Hill-Sachs lesion if any. A treatment algorithm is proposed, based on the current literature in an effort to create a consensus for these injuries. For the acute shoulder fracture-dislocations, an open reduction should be performed. For the chronic fracture/dislocations in the elderly low-demand patients, conservative treatment should be performed. For the rest of the patients, depending on the severity of the Hill-Sachs lesion different surgical options are available such as the McLaughlin technique, the use of an allograft, osteotomy or arthroplasty.

Arthroscopic Knotless Subscapularis Bridge Technique for Reverse Hill-Sachs Lesion With Posterior Shoulder Instability

Posterior shoulder dislocations are an uncommon cause of glenohumeral instability; they are frequently missed and are associated with humeral head defects and capsulolabral lesions. Despite surgical treatment often being mandatory, there is still no standardized treatment for anterior impaction fractures of the humeral head (reverse Hill-Sachs lesions). Arthroscopic surgery is typically indicated, with a tendency toward resorting to knotless techniques in recent years. We present a method for the treatment of posterior shoulder dislocations with engaging reverse Hill-Sachs lesions that achieves full defect coverage using an arthroscopic all-in-the-box knotless subscapularis bridge technique with 2 anchors-with one crossing the subscapularis tendon and the other embracing it-along with posterior capsulolabral complex restoration. This promising technique is a potentially superior alternative for the treatment of these lesions that can also be used in the presence of concomitant partial subscapularis tears.

Return to Sport After Arthroscopic Treatment of Posterior Shoulder Instability

Background:

Arthroscopic treatment of posterior shoulder instability has become more popular and effective in recent years, but few data are available concerning the rate of return to sport.

Purpose:

To present our experiences with arthroscopic posterior labral reconstruction in athletes and review our results, with a particular focus on the rate of return to sport.

Study Design:

Case series; Level of evidence, 4.

Methods:

Included in the study were 40 arthroscopic stabilizations performed because of posterior shoulder instability in 37 athletes at a single institution. During follow-up, the athletes’ rate of return to sport was calculated. Shoulder function was evaluated based on a pre- versus postoperative comparison of the Rowe instability score and the American Shoulder and Elbow Surgeons score. Additionally, the return-to-sport rate was compared among different subgroups: traumatic versus atraumatic origin of injury, competitive versus recreational athletes, high-risk versus low-risk sport, and posterior-only versus anterior and posterior stabilization. Data were statistically analyzed using paired-samples t test and nonparametric Fisher exact test.

Results:

The average follow-up period was 54.4 months (range, 24-112 months). Three shoulders (7.5%) continued to have posterior subluxations postoperatively. There were 34 excellent, 3 good, and 3 fair results based on the Rowe score (average postoperative score, 92.9), and patients achieved an average postoperative American Shoulder and Elbow Surgeons score of 92.7. The pre- to postoperative improvement was statistically significant in both scoring systems (P < .001). Of the 37 patients, 36 (98.2%) were able to return to sport activity: 27 of them (72.9%) to their original sport and 19 (51.4%) at their preinjury level. A significantly higher rate of return to the same sport occurred in athletes who had traumatic injury compared with a subgroup of athletes without a traumatic event (P < .02).

Conclusion:

More than half of the athletes were able to return to their preinjury level of sport after arthroscopic posterior labral reconstruction. In addition, low recurrence rates and good functional outcomes were seen in >90% of the patients, and 98% returned to sport activity. The athletes had a significantly higher rate of return to sport if their posterior shoulder instability had a clear traumatic origin.

Treatment of unusual locked posterior fracture-dislocation of the shoulder: a case series

Background

Locked posterior fracture-dislocation of the shoulder (LPFDS) is a very rare injury that occurs predominantly in young patients following high-energy trauma. The long-term outcome of the treatment of this injury is often poor. This study sought to present the characteristics of injury, discuss the pathological anatomy, and to report the treatment outcomes of our case series.

Methods

Between January 2012 and May 2018, a total of 234 patients who underwent surgical treatment for proximal humerus fractures were reviewed. Among them, six patients (mean age, 54.7 years; range, 35-76 years) with LPFDS were included in this study. Four patients were treated with open reduction and internal fixation (ORIF) with locking plates, one with hemiarthroplasty, and one with reverse total shoulder arthroplasty. Clinical results were evaluated by Constant, American Shoulder and Elbow Surgeons (ASES), and visual analog scale (VAS) scores and radiologic evaluation was conducted using follow-up radiographs.

Results

The mean length of follow-up was 26.2 months (range, 12-54). The mean Constant, ASES, and VAS scores were 66.7, 65.5, and 2.2, respectively. Four patients who underwent ORIF achieved bony union, but avascular necrosis (AVN) of the humeral head was observed in two patients. No complications were observed in the patients who underwent arthroplasty surgery until final follow-up.

Conclusions

In the treatment of LPFDS, replacement arthroplasty can produce predictable results. The approach of ORIF may be considered as a first choice of treatment in young patients but is sometimes correlated with postoperative complications such as AVN and the functional outcomes may be unpredictable. Therefore, patients should undergo careful diagnosis and treatment of this type of injury.

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.

Return to sport after surgical treatment for posterior shoulder instability: a systematic review

Purpose

To report the rate of return to sport after surgical treatment for posterior shoulder instability among athletes.

Methods

A systematic review of the literature regarding rate of return to sport after surgical treatment for posterior shoulder instability was undertaken. The primary outcome measure was return to sport. The secondary outcome measures included rate of return to sport to preinjury level, time to return to sport, injury type, reoperations after primary surgery, and objective patient-reported outcome data. Data is summarized with ranges and tables.

Results

A total of 23 studies met inclusion criteria. The rate of return to sport ranged from 57.9%-100%. The rate of return to sport to the preinjury level ranged from 47.4%-100%. Time to return to sport ranged from 4.3-7.7 months. Furthermore, 66% of subjects had an acute traumatic injury and 34% were of insidious onset. The most commonly reported outcome measures were American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores and visual analog scale (VAS) pain scores. At a minimum of 1-year follow-up, ASES and VAS pain scores improved. Revision rates ranged from 0%-36.8%.

Conclusion

The systematic review demonstrated high rates of return to sport and relatively high rates of return to preinjury level of sport among all athletes who underwent surgical treatment for posterior shoulder instability. Objective patient-reported outcome metrics improved postoperatively whereas revision rates remained low.

A Modified Reverse Remplissage Procedure for Management of a Locked Posterior Shoulder Dislocation

Posterior shoulder dislocation is rare and often represents a diagnostic and therapeutic challenge. An impaction fracture of the anteroinferior aspect of the humeral head (called a reverse Hill-Sachs (RHS) fracture) is always present in case of chronic locked posterior dislocation. Surgical management is required and decided on the delay between the trauma and the diagnosis and the importance of the RHS (in percentage). The authors present a chronic locked posterior shoulder dislocation in a 32-year-old active male with a reverse Hill-Sachs lesion of more than 40%. An open reduction was required, and stabilization was achieved with a modified remplissage technique with detachment of the upper quarter of the subscapularis tendon. Three years after the surgery, the patient recovered an excellent functional level with a stable shoulder.

No difference in outcomes of surgical treatment for traumatic and atraumatic posterior shoulder instability

BACKGROUND

Posterior shoulder instability is a rare pathology and accounts for 2-10% of all shoulder instabilities. The purpose of this study was to compare pain and functional scores following surgical treatment of traumatic and atraumatic PSI.

HYPOTHESIS

The authors hypothesize that patients with traumatic PSI are at greater risks of residual pain and recurrent subluxation.

MATERIAL AND METHODS

The records of 150 patients operated for PSI between 2000 and 2015 at 10 different centers were analysed. Inclusion criteria were symptomatic PSI (subluxation and/or pain) with radiographic signs of posterior glenoid erosion or fracture, posterior labral tears, or reverse Hill Sachs lesions. One hundred and seventeen patients were eligible, of which 84% presented symptoms of subluxation and/or dislocation, and 16% were painful without clinical symptoms of subluxation and/or dislocation. Patients were evaluated at 48±33months (range: 12-159) using the Constant, Walch-Duplay and Rowe scores, with pain on Visual Analogic Scale (pVAS).

RESULTS

Compared to atraumatic PSI, traumatic PSI was more prevalent in men (84.4% vs 61.9%, p=0.031), and tended to have fewer pain symptoms (15.8% vs 23.8%, n.s). Atraumatic PSI was more likely to affect the dominant arm, although the difference was not significant (81.0% vs 59.4%, n.s.). Traumatic PSI did not differ from atraumatic PSI in terms of preoperative lesional characteristics, procedures performed, or postoperative pain and instability. Although these differences were not statistically significant, it is worth noting that traumatic PSI patients experienced more recurrence of instability (15.6% vs 4.8%, p=0.298), and lower pain on VAS (1.5±2.3 vs 2.6±3.0, n.s.) compared to atraumatic PSI.

DISCUSSION

Functional scores did not significantly differ between traumatic and atraumatic PSI after surgery, although traumatic PSI patients tended to have a higher recurrence of instability, while atraumatic PSI patients tended to remain more painful.

LEVEL OF EVIDENCE

IV, retrospective cohort study.

New Reduction Technique for Traumatic Posterior Glenohumeral Joint Dislocations

Traumatic posterior glenohumeral joint (GHJ) dislocation is a rare condition which can be missed if it is not suspected. Clinical presentation may be subtle, but limitation in range of motion in patient with acute trauma should warrant obtaining a thorough history, performing a comprehensive physical examination, and acquiring at least a 3-view plain radiography. Reduction can be achieved with a direct pressure to the posterior aspect of the humeral head.

Glenoid Cartilage Lesions Compromise Outcomes of Surgical Treatment for Posterior Shoulder Instability

Background:

Posterior shoulder instability is associated with nonspecific symptoms, including pain, subluxation, and functional impairment, which complicate its diagnosis and management. Owing to the rarity of the condition, there are no present decision tools for its diagnosis and treatment.

Purpose:

To investigate demographic, lesional, and surgical factors that influence functional outcomes in patients treated for posterior shoulder instability.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

We analyzed the clinical and radiographic records of 150 patients treated surgically for isolated posterior shoulder instability at 10 centers between 2000 and 2015, of which 144 were eligible for inclusion: 114 men (79%) and 30 women (21%) (mean ± SD age, 28.7 ± 9.6 years). The mean time between onset of symptoms and surgery was 66 ± 75 months. Shoulder instability was of traumatic origin in 115 patients (80%). The primary treatment was bone-block procedures for 65 patients (45%), posterior Bankart repair for 67 (47%), and capsular plication for 12 (8%). Patients were assessed with the Constant and Walch-Duplay scores at a mean follow-up of 51 ± 32 months (range, 12-159 months). Uni- and multivariable regression analyses were performed to determine associations between clinical scores and sex, age, traumatic origin, type of lesion, type of procedure, and follow-up.

Results:

At final follow-up, subluxations or dislocations recurred in 24 patients (17%). The overall Constant score was 86.2 ± 14.5, with a pain component of 12.6 ± 3.5. The Walch-Duplay score was 79.8 ± 24.2. Multivariable regressions revealed that the presence of a glenoid cartilage lesion was the only factor associated with worse Constant score (beta = –10; P = .013) and Walch-Duplay score (beta = –16.7; P = .024) across all subcomponents.

Conclusion:

The only factor that jeopardized functional outcomes of posterior instability surgery was the presence of glenoid cartilage lesions. Knowing that shoulders with glenoid cartilage lesions are at greater risk of residual pain or instability could help manage patient expectation and justify faster intervention before lesions deteriorate.

Arthroscopic Knotless Modified McLaughlin Procedure for Reverse Hill-Sachs Lesions

Posterior shoulder dislocations often are associated with an impression fracture involving the anterior humeral head known as a reverse Hill-Sachs lesion. These injuries can result in significant bone defects that require surgical management to prevent them from engaging the posterior glenoid. We present a modified arthroscopic, knotless McLaughlin procedure (tenodesis of the subscapularis tendon into the bone defect) for the treatment of small-to medium-sized, engaging Hill-Sachs lesions. The knotless fashion aims to eliminate potential problems associated with knot tying, such as knot migration, knot impingement, and chondral abrasion.

Arthroscopically Assisted Reduction in a Chronic Locked Posterior Shoulder Dislocation

Neglected posterior shoulder dislocation is a difficult condition in terms of decision making and surgical technique. Not only the bony deformity but also the soft tissue and patient's underlying disease are of concern. Whether the poor results are associated with a time delay or the treatment method is not clear yet. To date, there is neither a consensus nor treatment guidelines. We describe an arthroscopically assisted reduction and open McLaughlin procedure. The advantage of this procedure is preservation of the soft tissue of the anterior part of the shoulder during the surgical reduction technique for chronic neglected posterior shoulder dislocation cases.

Posterior Shoulder Dislocation During Morning PT: A Case Report

Posterior shoulder dislocation should be considered in the differential diagnosis of acute shoulder pain and immobility following trauma. Although far less common then the anterior dislocation, it is associated with high rates of comorbidity. Seventy-nine percent of posterior shoulder dislocations are missed on initial presentation, which is partially responsible for the high rate of comorbidity associated with these injuries. The mechanism of injury is varied from generalized seizure to minor trauma, which adds to the complexity of the diagnosis. There is a well-documented "vulnerable position" described as injury to the arm while it is in a flexed, adducted, and internally rotated position that is highly associated with posterior shoulder dislocation. The plain film scapular Y is the most clinically significant imaging and can be used alone to diagnose the injury, although ancillary imaging such as magnetic resonance imaging is often warranted. Once this rare condition has been diagnosed, there are a number of appropriate reduction techniques available to the health care provider. Presented here is a case of posterior shoulder dislocation that occurred while doing pushups for routine morning physical training. Also discussed are keys to recognition and treatment as well as a brief discussion of associated complications of the injury.

The aetiology of posterior glenohumeral dislocations and occurrence of associated injuries

Aims

The glenohumeral joint is the most frequently dislocated articulation, but possibly due to the lower prevalence of posterior shoulder dislocations, approximately 50% to 79% of posterior glenohumeral dislocations are missed at initial presentation. The aim of this study was to systematically evaluate the most recent evidence involving the aetiology of posterior glenohumeral dislocations, as well as the diagnosis and treatment.

Materials and Methods

A systematic search was conducted using PubMed (MEDLINE), Web of Science, Embase, and Cochrane (January 1997 to September 2017), with references from articles also evaluated. Studies reporting patients who experienced an acute posterior glenohumeral joint subluxation and/or dislocation, as well as the aetiology of posterior glenohumeral dislocations, were included.

Results

A total of 54 studies met the inclusion criteria. In total, 182 patients were included in this analysis; study sizes ranged from one to 66 patients, with a mean age of 44.2 years (sd 13.7). There was a higher proportion of male patients. In all, 216 shoulders were included with 148 unilateral injuries and 34 bilateral. Seizures were implicated in 38% of patients (n = 69), with falls, road traffic accidents, electric shock, and iatrogenic reasons also described. Time to diagnosis varied across studies from immediate up to a delay of 25 years. Multiple associated injuries are described.

Conclusion

This review provides an up-to-date insight into the aetiology of posterior shoulder dislocations. Our results showed that seizures were most commonly implicated. Overall, reduction was achieved via open means in the majority of shoulders. We also found that delayed diagnosis is common.

The role of bone in glenohumeral stability

Shoulder stability depends on several factors, either anatomical or functional. Anatomical factors can be further subclassified under soft tissue (shoulder capsule, glenoid rim, glenohumeral ligaments etc) and bony structures (glenoid cavity and humeral head).

Normal glenohumeral stability is maintained through factors mostly pertaining to the scapular side: glenoid version, depth and inclination, along with scapular dynamic positioning, can potentially cause decreased stability depending on the direction of said variables in the different planes. No significant factors in normal humeral anatomy seem to play a tangible role in affecting glenohumeral stability.

When the glenohumeral joint suffers an episode of acute dislocation, either anterior (more frequent) or posterior, bony lesions often develop on both sides: a compression fracture of the humeral head (or Hill–Sachs lesion) and a bone loss of the glenoid rim. Interaction of such lesions can determine ‘re-engagement’ and recurrence.

The concept of ‘glenoid track’ can help quantify an increased risk of recurrence: when the Hill–Sachs lesion engages the anterior glenoid rim, it is defined as ‘off-track’; if it does not, it is an ‘on-track’ lesion. The position of the Hill–Sachs lesion and the percentage of glenoid bone loss are critical factors in determining the likelihood of recurrent instability and in managing treatment.

In terms of posterior glenohumeral instability, the ‘gamma angle concept’ can help ascertain which lesions are prone to recurrence based on the sum of specific angles and millimetres of posterior glenoid bone loss, in a similar fashion to what happens in anterior shoulder instability.

Cite this article: EFORT Open Rev 2018;3:632-640. DOI: 10.1302/2058-5241.3.180028

Posterior Shoulder Dislocation Associated With the Head (Splitting) and Humeral Neck Fracture: Impact of Understanding Radiologic Signs and Experience With an Extended Deltopectoral Approach

In this paper, our main objective was to emphasize the competency of extended deltopectoral exposure, enforced with the supraspinatus and subscapularis detachment, to gain access to the entire head. The second important point in this paper was to underline the importance of the knowledge that is necessary for interpreting classic radiologic signs of posterior fracture-dislocation of the shoulder. A 47-year-old woman fell down directly onto her shoulder while she was skiing. She was diagnosed with posterior shoulder dislocation, associated with fracture of the head (head splitting) and humeral neck fracture, with the aid of plain radiographs and computed tomographic results. The patient was treated with open reduction and internal fixation of the fracture, through the extended deltopectoral approach, which was augmented with rotator cuff detachment. At the 1-year follow-up, x-rays showed stable fixation with good evidence of healing. One year after the surgery, the patient had no pain, and she regained most of her functionality in her right shoulder with 140 to 150 degrees of lateral elevation (abduction), 140 to 150 degrees of forward flexion , internal rotation hand at T12 vertebra (slightly restricted). These results showed good functionality, with a painless shoulder at the 1-year follow-up. The "double shadow" and "lightbulb" signs are indicative of posterior shoulder fracture-dislocation, and augmented (with the detachment of supraspinatus and subscapularis tendons) traditional deltopectoral incision is suitable for managing these kinds of difficult fracture dislocations.

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.

Outcomes of capsulolabral reconstruction for posterior shoulder instability

BACKGROUND

Surgical treatment of isolated posterior shoulder instability-a rare and often misdiagnosed condition-is controversial because of poor outcomes. Failure of physical therapy in symptomatic young athletes requires capsulolabral reconstruction or bone block procedures. The goal of this study was to report the outcomes of patients who have undergone surgical capsulolabral reconstruction and to look for risk factors that contribute to failure of this procedure.

MATERIAL AND METHOD

We analyzed the outcomes of 101 patients who underwent capsulolabral reconstruction: 83 included retrospectively, 18 included prospectively. The procedures were performed alone or in combination with capsular shift, labral repair, closure of the rotator interval and notch remplissage. The primary endpoint was failure of the procedure, defined as recurrence of the instability and/or pain. We also determined the outcomes based on specific (Walch-Duplay, modified Rowe) and non-specific (Constant, resumption of activities) scores of shoulder instability.

RESULTS

The results were satisfactory despite a high failure rate: 35% in the retrospective cohort with 4.8±2.6 years' follow-up and 22% in the prospective cohort with 1.1±0.3 years' follow-up. The various outcome scores improved significantly. Ninety-two percent of patients returned to work and 80% of athletes returned to their pre-injury level of sports. Eighty-five percent of patients were satisfied or very satisfied after the surgery. No risk factors for failure were identified; however, failures were more common in older patients, those who underwent an isolated procedure and those who had unclassified clinical forms.

CONCLUSION

Treatment of posterior shoulder instability by capsulolabral reconstruction leads to good clinical outcomes; however, the recurrence rate is high.

LEVEL OF EVIDENCE

4 - retrospective study.

Posterior shoulder dislocation with associated reverse Hill-Sachs lesion: treatment options and functional outcome after a 5-year follow up

Background

The current study describes several surgical techniques for the treatment of the reverse Hill - Sachs lesion after posterior shoulder dislocation; we also aimed to present long term results followed for a minimum of five years.

Methods

This study is a prospective case series of 17 patients who were treated in our clinic between 2008 and 2011. Patients with a defect size smaller than 25% of the articular surface were treated conservatively. An endoprosthesis of the glenohumeral joint was implanted in patients with a defect size bigger than 40%. All remaining patients were treated by a variety of operative techniques, depending on the quality of the bone and size of the defect.

Results

Twelve of seventeen patients had a defect size of the humeral articular surface between 25% and 40% with a mean age of 39 years. Depending on the defect size these patients were treated with retrograde chondral elevation, antegrade cylindrical graft or a graft of the iliac bone crest with an open approach. All the procedures showed fair results, e.g. the open approach with a graft of the iliac bone crest (2010: Dash 3.89, Constant 90.33, Rowe 86.67; 2015: Dash 2.22, Constant 92.00, Rowe 93.33).

Conclusion

The open approach is not a disadvantage for the functional outcome. The treatment algorithm should involve the superficial size of the defect as well as the depth of the defect and the time interval between the dislocation and the surgical treatment.

Trial registration

223/2012BO2, 02 August 2010.

The Posterior Unstable Shoulder: Natural History, Clinical Evaluation and Imaging

Background:

There is a low incidence of posterior instability which is present in only 2% to 10% of all unstable shoulders. The posterior instable shoulder includes different manifestations like fixed dislocation, recurrent subluxation or dislocation.

Methods:

Research and online content related to posterior instability is reviewed. Natural history, clinical evaluation and imaging are described.

Results:

An awareness of the disorder, together with a thoughtful evaluation, beginning with the clinical history, usually leads to proper diagnosis. An appropriate physical exam, taking in account hyperlaxity and specific tests for posterior instability should be done.

Conclusion:

Posterior shoulder instability is an uncommon condition and is challenging to diagnose. There is not a single injury that is responsible for all cases of recurrent shoulder dislocation or subluxation, and the presence of soft tissue lesions or bone alterations should be evaluated, with the use of adequate simple radiology and multiplanar imaging.

Posterior shoulder dislocation with a reverse Hill-Sachs lesion treated with frozen femoral head bone allograft combined with osteochondral autograft transfer

Management of a posterior shoulder dislocation with an associated reverse Hill-Sachs lesion is challenging, both diagnostically and therapeutically. Diagnosis is frequently delayed or missed, whereas the resulting humeral head defect is often larger and more difficult to salvage than in anterior shoulder dislocations. This report presents the case of a 29-year-old male with a recurrent posterior shoulder dislocation associated with a large reverse Hill-Sachs defect, treated with bone augmentation of the lesion with a combination of fresh femoral head allograft and a locally harvested humeral head autograft transfer, with a successful outcome. Level of evidence V.

Defect Characteristics of Reverse Hill-Sachs Lesions

BACKGROUND

Little scientific evidence regarding reverse Hill-Sachs lesions (RHSLs) in posterior shoulder instability exists. Recently, standardized measurement methods of the size and localization were introduced, and the biomechanical effect of the extent and position of the defects on the risk of re-engagement was determined.

PURPOSE

To analyze the characteristics and patterns of RHSLs in a large case series using standardized measurements and to interpret the results based on the newly available biomechanical findings.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

In this multicenter study, 102 cases of RHSLs in 99 patients were collected from 7 different shoulder centers between 2004 and 2013. Patient- as well as injury-specific information was gathered, and defect characteristics in terms of the size, localization, and depth index were determined on computed tomography or magnetic resonance imaging scans by means of standardized measurements. Additionally, the position (gamma angle) of the posterior defect margin as a predictor of re-engagement was analyzed.

RESULTS

Three types of an RHSL were distinguished based on the pathogenesis and chronicity of the lesion: dislocation (D), locked dislocation (LD), and chronic locked dislocation (CLD). While the localization of the defects did not vary significantly between the subgroups (P = .072), their mean size differed signficantly (D: 32.6° ± 11.7°, LD: 49.4° ± 17.2°, CLD: 64.1° ± 20.7°; P < .001). The mean gamma angle as a predictor of re-engagement was similarly significantly different between groups (D: 83.8° ± 14.5°, LD: 96.5° ± 17.9°, CLD: 108.7° ± 18.4°; P < .001). The orientation of the posterior defect margin was consistently quite parallel to the humeral shaft axis, with a mean difference of 0.3° ± 8.1°.

CONCLUSION

The distinction between the 3 different RHSL types based on the pathogenesis and chronicity of the defect helps identify defects prone to re-engagement. The gamma angle as a measurement of the position of the posterior defect margin and therefore a predictor of re-engagement varies significantly between the defect types.

Bilateral posterior shoulder dislocation after electrical shock: A case report

Introduction

Posterior dislocation of the shoulder is a rare and commonly missed injury. Unilateral dislocations occur mostly due to trauma. Bilateral posterior shoulder dislocations are even more rare and result mainly from epileptic seizures. Electrical injury is a rare cause of posterior shoulder dislocation. Injury mechanism in electrical injury is similar to epileptic seizures, where the shoulder is forced to internal rotation, flexion and adduction.

Presentation of case

This report presents a case of bilateral posterior shoulder dislocation after electrical shock. We were able to find a few individual case reports describing this condition. The case was acute and humeral head impression defects were minor. Our treatment in this case consisted of closed reduction under general anesthesia and applying of orthoses which kept the shoulders in abduction and external rotation. A rehabilitation program was begun after 3 weeks of immobilization. After 6 months of injury the patient has returned to work. 20 months postoperatively, at final follow-up, he was painless and capable of performing all of his daily activities.

Discussion

The amount of bilateral shoulder dislocations after electrical injury is not reported but is known to be very rare. The aim of this case presentation is to report an example for this rare entity, highlight the difficulties in diagnosis and review the treatment options.

Conclusion

Physical examination and radiographic evaluation are important for quick and accurate diagnosis.

•

Posterior dislocation of the shoulder is a rare and commonly missed injury.

•

Electrical injury is a rare cause of posterior shoulder dislocation.

•

Physical examination and radiographic evaluation are important for quick and accurate diagnosis.

•

If the diagnosis is made early and the humeral head impression defect is less than 25%, closed reduction followed by a good rehabilitation program can lead to successful results.

Traumatic posterior shoulder dislocation with a large engaging Hill-Sachs lesion: splinting technique

Posterior shoulder dislocations are rare and are often associated with seizures, electrocution, and high-energy trauma. They can be missed and, therefore, left untreated. Early diagnosis and treatment can help avoid future complications and surgical intervention.

Arthroscopic treatment of posterior shoulder instability: a systematic review

PURPOSE

We performed a systematic review of the literature to determine the early and midterm outcomes of arthroscopic stabilization for posterior shoulder instability.

METHODS

We searched PubMed, Embase, and the Cochrane Database of Systematic Reviews for related articles published in the English language. The 2 authors selected studies for inclusion or exclusion. The inclusion criteria included a minimum of 1 year of follow-up, with at least 20 patients in the study population.

RESULTS

We included 6 studies, with a total of 387 patients (396 shoulders). All studies were retrospective, Level IV studies, except for 1 prospective study (Level II). In 81.06% of cases, patients reported a significant traumatic episode. The mean follow-up period was 44.4 months, and the mean recurrence rate was 5.37%. Most of the patients were able to return to sport (mean, 92.5%).

CONCLUSIONS

The early and midterm results of arthroscopic stabilization of the shoulder for posterior instability are promising. Most of the patients were satisfied with the results of surgery and were able to return to sport. Larger studies and more prospective randomized trials are needed to confirm these findings.

LEVEL OF EVIDENCE

Level IV, systematic review of 1 Level II study and 5 Level IV studies.