SECEC Didier Patte Prize 2023: the ABC classification of posterior shoulder instability.

BACKGROUND: The ABC classification has recently been proposed as a comprehensive classification system for posterior shoulder instability (PSI). The purpose of this study was to analyze the comprehensiveness as well as inter-rater and intrarater reliability of the ABC classification. METHODS: All consecutive patients presenting with unidirectional PSI from June 2019 to June 2021 were included in a prospective study. No patients were excluded, leaving a consecutive series of 100 cases of PSI in 91 patients. All recorded clinical and imaging data were used to create anonymized clinical case vignettes, which were evaluated twice according to the ABC classification at the end of the recruitment period in random sequential order by 4 independent raters (2 experienced shoulder surgeons and 2 orthopedic residents) to analyze the comprehensiveness as well as inter-rater and intrarater reliability of the ABC classification for PSI and to describe differences in characteristics among subtypes. Group A was defined as a first-time singular PSI event <3 months in the past regardless of etiology and is further subdivided into type 1 and type 2 depending on the occurrence of a subluxation (A1) or dislocation (A2). Group B comprises recurrent dynamic PSI regardless of time since onset and is further subdivided by the cause of instability into functional (B1) and structural (B2) dynamic PSI. Group C includes chronic static PSI with posterior humeral decentering that can be either constitutional (C1) or acquired (C2). RESULTS: None of the cases was deemed unsuitable to be classified based on the proposed system by the observers. After consensus agreement between the 2 expert raters, 16 cases were attributed to group A (8 type A1 and 8 type A2); 64, to group B (33 type B1 and 31 type B2); and 20, to group C (11 type C1 and 9 type C2). The expert raters agreed on the classification subtypes in 99% and 96% of the cases during the first rating and second rating, respectively (intraclass correlation coefficients [ICCs], 0.998 and 0.99, respectively). The intraobserver reliability was excellent for both raters. The beginners reached the same conclusion as the consensus agreement in 94% of the cases (ICC, 0.99) and 89% of the cases (ICC, 0.97) during the first round and 94% each (ICC, 0.97) during the second round. The intraobserver reliability was excellent for both beginners. Overall, discrepancies between raters were found between groups B1 and B2 (n = 14), groups B2 and C2 (n = 4), groups B1 and C1 (n = 1), and groups A1 and B2 (n = 1). In general, each subtype showed distinctive clinical and imaging characteristics that facilitated the diagnosis. CONCLUSION: The presented ABC classification for PSI is a comprehensive classification with a high reliability and reproducibility. However, a gradual transition and potential progression between the subtypes of PSI must be considered. The reliable distinction between different subtypes of PSI based on etiology and pathomechanism provides a standardized basis for future investigations on treatment recommendations.

Injury Mechanism of Acute Anterior Shoulder Dislocation Associated with Glenoid and Greater Tuberosity Fractures: A Study Based on Fracture Morphology.

OBJECTIVE: Based on the morphological characteristics of glenoid and greater tuberosity (GT) fractures and the relationship between them, we explored the injury mechanism of acute anterior shoulder dislocation associated with glenoid and GT fractures. METHODS: From December 2013 to December 2019, we retrospectively reviewed the clinical data of patients who were diagnosed with acute anterior shoulder dislocation associated with glenoid and GT fractures in our hospital. According to the fracture site, a glenoid fracture group and a greater tuberosity fracture (GT) group were established, and the morphological characteristics of both glenoid and GT fractures were measured and statistically analyzed. RESULTS: A total of 41 patients (43 shoulders) met the inclusion criteria (39 unilateral shoulders and 2 bilateral shoulders). The mean age was 50.21 years (range, 22-71 years). A total of 27 shoulder injuries (62.8%) were split GT fractures and 33 shoulder injuries (76.7%) were combined with rotator cuff tears. The mean size of glenoid fragments was 30.16% and the mean displacement was 8.85 mm. The mean size of GT fragments was 28.43 mm. The mean superoinferior and anteroposterior displacements of the GT fragment were 6.77 mm and 4.96 mm, respectively. There was a negative correlation between the size of glenoid and GT fracture fragments (r = -0.64, P < 0.05). The glenoid fragments in the Ideberg type Ia glenoid fracture group were smaller than those in the Ideberg type II glenoid fracture group (28.41% and 40.95%, respectively), while the size of GT fragments in the type Ia group were larger than those in the type II group (29.77 mm and 20.21 mm, respectively) (P < 0.05). The GT fragments in the split GT fracture group were larger than those in the avulsion or depression GT fracture group (33.69 mm, 19.07 mm and 21.12 mm, respectively), while the size of glenoid fragments in the split GT fracture group were smaller than those in the avulsion or depression GT fracture group (23.57%, 41.37%, and 43.42%, respectively) (P < 0.05). As for the displacement direction of GT fragments, depression fractures were mainly inferior displacements, avulsion fractures were mainly anterosuperior displacements, while split fractures were mainly posteroinferior displacements (P < 0.05). Multiple regression analysis suggested that the type and the fragment size of GT fractures have a significant influence on the size of glenoid fragments. CONCLUSION: Acute anterior shoulder dislocations associated with glenoid and GT fractures are often combined with rotator cuff tears. There is a negative correlation between the size of glenoid and GT fragments, and split GT fractures are most common. Such injuries are highly correlated to the relative spatial location between the GT and the glenoid when the shoulder dislocates.

Surgical outcomes in the Frequency, Etiology, Direction, and Severity (FEDS) classification system for shoulder instability.

BACKGROUND: The Frequency, Etiology, Direction, and Severity (FEDS) system was developed as a simple but reliable method for classifying shoulder instability based on 4 factors attainable by history and physical examination: frequency (solitary, occasional, or frequent); etiology (traumatic or atraumatic); direction (anterior, posterior, or inferior); and severity (subluxation or dislocation). This study investigated the epidemiology and 2-year surgical outcomes for the FEDS categories in the prospective Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort. METHODS: At the time of surgery, 1204 patients were assigned to the FEDS categories. Follow-up data were available for 636 of 734 patients (86.6%) who had undergone surgery at least 2 years prior to analysis. The most common categories were further analyzed by patient-reported outcomes (PROs) (American Shoulder and Elbow Surgeons, Western Ontario Shoulder Instability index, Single Assessment Numeric Evaluation scores) and rates of recurrent subluxation, recurrent dislocation, and revision surgery. RESULTS: Of the 36 FEDS categories, 16 represented at least 1% of patients. Occasional traumatic anterior dislocation (OTAD) was the most common category, with 16.4% of patients. Five other anterior categories (solitary traumatic anterior subluxation, occasional traumatic anterior subluxation [OTAS], frequent traumatic anterior subluxation [FTAS], solitary traumatic anterior dislocation, and frequent traumatic anterior dislocation) and one posterior category (solitary traumatic posterior subluxation [STPS]) represented at least 5% of patients. PROs improved significantly for each category. The highest rates of recurrent subluxation occurred in FTAS, OTAS, and OTAD cases; dislocation, OTAS and FTAS cases; and further surgery, OTAD cases. The lowest rates of failure occurred in STPS cases. Downward trends in PROs and higher failure rates were noted with an increasing number of preoperative dislocations. CONCLUSION: Different FEDS categories showed varying degrees of improvement and failure rates, indicating that the system can be used to provide prognostic insight for presurgical education. Overall, outcomes decreased with a higher number of preoperative dislocations.

Global Perspectives on Management of Shoulder Instability: Decision Making and Treatment.

The glenohumeral joint is prone to instability. Patients with instability should have a physical examination. Imaging studies can provide additional information. Classification schemes that into account soft tissue pathology, neuromuscular control, bone loss, and activity level. An arthroscopic Bankart repair is the mainstay for unidirectional instability. Bone block procedures are indicated for patients with bone loss or a failed attempt at stabilization surgery. The arthroscopic Latarjet is a promising option for these patients. For patients with multidirectional instability, prolonged rehabilitation is indicated, followed by capsular plication or inferior capsular shift if instability is unresponsive to physical therapy.

Shoulder Terrible Triad: Classification, Functional Results, and Prognostic Factors.

INTRODUCTION: The shoulder terrible triad (STT) is a traumatic anterior shoulder dislocation, associated with rotator cuff (RC) tear and nerve injury from the brachial plexus. This study aimed to describe the functional results and prognostic factors of surgery in patients with STT. METHODS: Thirty consecutive patients with acute STT were included at the same institution. All patients were examined with x-rays, MRI, and electromyography. Surgical treatment in the acute setting was indicated to address an RC injury or a displaced greater tuberosity fracture. Variables registered on the day of surgery were preoperative Constant and Western Ontario Rotator Cuff (WORC) scores and injury pattern. At final discharge, Constant, American Shoulder and Elbow Surgeons (ASES), WORC, and subjective shoulder value scores were recorded by an independent evaluator. RESULTS: Twenty-seven patients underwent a complete follow-up. The dominant arm was affected in 50% of cases. The mean follow-up was 27 (12 to 43) months. The mean WORC and Constant scores improved from 1,543 to 1,093 (P = 0.015) and 31 to 54 (P = 0.003), respectively. The ASES and subjective shoulder value scores at the end of the follow-up were 60 and 56 points, respectively. RC tears and nerve injuries that did not involve the axillary or suprascapular nerves were associated to better results than greater tuberosity fractures and injuries to the axillary or suprascapular nerves, respectively, in WORC (P = 0.028), Constant (P = 0.024), and ASES scores (P = 0.035). Preoperative WORC and Constant scores were independent prognostic factors. CONCLUSIONS: The most frequent patterns include complete RC tears, anterior capsular injuries, and an axillary nerve injury. Patients had improved functional scores at the end of follow-up after surgery. Better functional results were correlated to RC tears, injuries to nerves with innervation distal to the shoulder, and higher preoperative Constant and WORC scores.

Return to sport after surgical treatment for high-grade (Rockwood III-VI) acromioclavicular dislocation.

PURPOSE: Acromioclavicular (AC) joint dislocations are common in a young and active population, especially in people performing contact sports. Full recovery with a fast and high rate of return to sport is desirable. This systematic review aims to combine patient outcomes in order to help surgeons in addressing patient expectations regarding the return to sport after surgical intervention for AC dislocations. METHODS: To conduct this systematic review, the PRISMA guidelines were followed. Articles were included if written in English or Dutch and evaluated return to sport after any type of surgical intervention for Rockwood types III to VI AC dislocations in patients practicing sports. Outcome parameters were return to sport, time to return to sport, level of sport, functional outcome scores and complications. RESULTS: Twelve studies involving 498 patients were included, of which 462 patients practiced sports. 432 (94%) patients returned to sport. The weighted mean time to return to sport was 4.0 months. 338 out of 401 patients (84%) returned to the same level of pre-injury sport and 35 patients (9%) lowered their level of sport. The weighted mean Constant score was 92 out of 100. CONCLUSION: The rate of return to sport after surgical intervention for Rockwood (RW) III-VI AC dislocations is high. However, the level of evidence was low and due to the methodological heterogeneity between studies, subgroup analyses of return to sport outcomes were not feasible. LEVEL OF EVIDENCE: Systematic review of level I-IV studies, level IV.

Epidemiology of the Frequency, Etiology, Direction, and Severity (FEDS) system for classifying glenohumeral instability.

HYPOTHESIS: The purpose of this multicenter epidemiologic study was to determine the distribution of patients within the Frequency, Etiology, Direction, and Severity (FEDS) classification system to determine which categories are of clinical importance. METHODS: Shoulder instability patients were identified using International Classification of Diseases, Ninth Revision coding data from 3 separate institutions from 2005-2010. Data were collected retrospectively. Details of instability were recorded in accordance with the FEDS classification system. Each patient was assigned a classification within the FEDS system. After all patients were assigned to a group, each group was individually analyzed and compared with the other groups. RESULTS: There are a total of 36 possible combinations within the FEDS system. Only 16 categories were represented by at least 1% of our patient population. Six categories captured at least 5% of all patients with shoulder instability. Only 2 categories represented greater than 10% of the population: solitary, traumatic, anterior dislocation, with 95 patients (24.8%), and occasional, traumatic, anterior dislocation, with 63 patients (16.4%). CONCLUSIONS: There are 16 categories within the FEDS classification that are clinically significant. Solitary, traumatic, anterior dislocation and occasional, traumatic, anterior dislocation were the most frequently observed in our cohort.

[Arthroscopic fracture treatment of the shoulder joint]. / Arthroskopische Frakturversorgung des Schultergelenks.

In recent years, the understanding of shoulder fractures has changed due to the progress of arthroscopy. In addition to the cosmetic result, the access morbidity, particularly the integrity of the subscapularis muscle in glenoid and scapular fractures, must be mentioned as an advantage of a minimally invasive approach. Furthermore, necessary secondary interventions, e. g. hook plate removal, can be prevented or minimized by modern implants and arthroscopic techniques.However, the available data and publications are almost exclusively limited to technical notes or small case series, so statements about faster recreation or potential reduction of infection risk cannot be made. Whether addressing concomitant injuries has an effect on the clinical and functional outcome is also unclear at the present time.

[Current aspects and new techniques in dislocation of the shoulder joint]. / Aktuelle Aspekte und neue Techniken bei Schultereckgelenksprengung.

With 12% of all injuries concerning the shoulder, acromioclavicular (AC) joint dislocations are a common injury especially in young and active patients. The Rockwood classification is widely accepted, which differentiates between six types depending on the degree of injury and the vertical dislocation. Because the classification does not adequately address the horizontal instability, its benefits are questionable and there is currently no consensus. For this reason, the classification and the therapy of these injuries are increasingly becoming the subject of scientific investigations. Whereas conservative treatment for type I and II injuries and operative treatment for type IV-VI injuries are widely accepted, there is still no agreement in treating type III lesions. The goal of this review article is to present the current evidence for the diagnostics, different classifications and therapeutic possibilities.

[Bony Bankart lesions and glenoid defects : From refixation techniques to bony augmentation]. / Knöcherne Bankart-Läsion und Glenoiddefekte : Von Techniken der Refixierung bis zur knöchernen Augmentation.

Rim defects of the anterior glenoid cavity are a main reason for residual shoulder instability after traumatic dislocation of the shoulder. These defects can be the result of a glenoid rim fracture or chronic glenoid erosion after repeated shoulder dislocations. Treatment concepts for these entities are entirely different. While in the acute fracture situation glenoid rim fractures can be treated operatively or non-operatively, augmentation of the anterior glenoid for stabilization of the shoulder should be considered if the defect exceeds 15-25% of the anterior glenoid. The purpose of this article is to summarize the diagnostics and indications for treatment of glenoid rim fractures. Radiological assessment and options for augmentation are reviewed for both acute fractures as well as chronic instability following an anterior glenoid rim defect.

Interobserver and intraobserver reliability of radiographic classification of acromioclavicular joint dislocations.

HYPOTHESIS AND BACKGROUND: The classification and treatment of acromioclavicular (AC) joint dislocations remain controversial. The purpose of this study was to determine the interobserver and intraobserver reliability of the Rockwood classification system. We hypothesized poor interobserver and intraobserver reliability, limiting the role of the Rockwood classification system in determining severity of AC joint dislocations and accurately guiding treatment decisions. METHODS: We identified 200 patients with AC joint injuries using the International Classification of Diseases, Ninth Revision code 831.04. Fifty patients met inclusion criteria. Deidentified radiographs were compiled and presented to 6 fellowship-trained upper extremity orthopedic surgeons. The surgeons classified each patient into 1 of the 6 classification types described by Rockwood. A second review was performed several months later by 2 surgeons. A κ value was calculated to determine the interobserver and intraobserver reliability. RESULTS: The interobserver and intraobserver κ values were fair (κ = 0.278) and moderate (κ = 0.468), respectively. Interobserver results showed that 4 of the 50 radiographic images had a unanimous classification. Intraobserver results for the 2 surgeons showed that 18 of the 50 images were rated the same on second review by the first surgeon and 38 of the 50 images were rated the same on second review by the second surgeon. CONCLUSION: We found that the Rockwood classification system has limited interobserver and intraobserver reliability. We believe that unreliable classification may account for some of the inconsistent treatment outcomes among patients with similarly classified injuries. We suggest that a better classification system is needed to use radiographic imaging for diagnosis and treatment of AC joint dislocations.

Radiographs and computed tomography scans show similar observer agreement when classifying glenoid morphology in glenohumeral arthritis.

BACKGROUND: Glenohumeral subluxation and glenoid morphology are commonly evaluated in primary osteoarthritis by use of the Walch classification. The reliability of this classification system has been analyzed only by computed tomography (CT). The purpose of this study was to determine the reliability of plain axillary radiographs compared with CT scans. METHODS: Three shoulder surgeons blindly and independently evaluated the radiographs and CT scans of 75 consecutive shoulders with primary glenohumeral osteoarthritis. Each observer classified all shoulders according to Walch in 4 separate sessions, each 6 weeks apart. There were 2 sessions using only radiographs and 2 using only CT scans. The order of shoulders evaluated was randomized. RESULTS: The first reading by the most senior observer based on CT was arbitrarily used as the "gold standard" (A1, 21; A2, 13; B1, 12; B2, 28; C, 1). The average intraobserver agreement for radiographs was 0.66 (substantial; 0.66, 0.59, and 0.74 for each observer). The average intraobserver agreement for CT scans was 0.60 (moderate; 0.53, 0.61, and 0.65). Pairwise comparisons between observers showed higher agreement for radiographs than for CT scans (0.48 vs. 0.39). The average agreement for observations on radiographs and CT scans was 0.42 (moderate; 0.40, 0.37, and 0.50). CONCLUSION: In this study, intraobserver agreement using the Walch classification based on axillary radiographs was substantial and compared favorably with agreement based on CT scans. The Walch classification provides a useful frame of reference when assessing subluxation and glenoid morphology in primary glenohumeral osteoarthritis, but not unlike other classification systems, it does not allow perfect agreement among observers.

Unclassified MR arthrography pattern evaluation in patients with episodes of recurrent antero-inferior shoulder dislocation.

PURPOSE: To evaluate prospectively the incidence of unclassifiable MR arthrography patterns of glenoid anterior-inferior labrum lesions, in patients with at least two episodes of recurrent antero-inferior shoulder dislocation. MATERIALS AND METHODS: The MR shoulder Arthrography images of 36 patients, with at least two episodes of recurrent antero-inferior dislocation, were prospectively evaluated, during a period between November 2015 and Mai 2016. All patients were contacted after 6 months of the MR arthrography to evaluate their course of treatment. The MR arthrography images were analyzed by two radiologists, respectively with 5 and 15 years of experience in musculoskeletal radiology. RESULTS: 36 cases of unclassifiable MR arthrography pattern of the anterior-inferior glenoid labrum were evaluated: in 13 out 36 cases (36.1%), the glenoid labrum has been described as "oedematous and swollen"; in 19 out 36 cases (52.8%), it has been described as "smooth" (not hypoplastic); in 4 out 36 cases (11.1%), it has been described as degenerated. CONCLUSION: The unclassifiable MR arthrography patterns of fibrocartilage glenoid lesions after episodes of recurrent antero-inferior dislocation are commons. The unclassifiable MR arthrography patterns require a careful consideration, in order to improve the diagnostic and therapeutic multidisciplinary approach.

Hill-Sachs lesion classification under arthroscopic findings.

BACKGROUND: The Hill-Sachs lesion (HSL) plays a role in recurrent glenohumeral joint instability. Currently, there are no studies based on the form characteristics of HSL. The purposes of this study were to report the HSL form characteristics and to determine whether they are correlated with number of prior subluxations and dislocations. METHODS: The study enrolled 134 consecutive patients diagnosed with anterior shoulder instability during an arthroscopic procedure. We classified the arthroscopic findings into 4 types, as follows: type 1, cyst type; type 2, gutter type; type 3, island type; and type 4, wide type. Subsequently, we investigated the correlation between each type and the number of shoulder subluxations and dislocations reported. The following data were analyzed: subluxation and dislocation history, arthroscopic findings, and maximum lesion size. RESULTS: Of the patients evaluated, 18, 32, 30, and 54 were classified as types 1 to 4, respectively. The mean numbers of shoulder dislocations were 3.3, 7.3, 6.0, and 12.0 for types 1 to 4, respectively. The wide type was correlated with more subluxations and dislocations than the other types (P = .001, .046, and .007, respectively). There were significant differences in mean width among all types (P < .0001). HSL width was correlated with lesion type and angle. CONCLUSION: We classified HSL into 4 types on the basis of visual inspection and found a correlation between lesion type and lesion size. However, HSL width was correlated with lesion type and angle; that is, the number of dislocations and subluxations does not affect HSL width.

Arthroscopic stabilisation of an acute acromioclavicular dislocation grade III in a patient with ectopic insertion of the pectoralis minor: technical considerations.

The different approaches used in arthroscopic stabilisation of the acromioclavicular joint are well known. However, and despite a great incidence of ectopic pectoralis minor insertion, an alternative choice for the use of arthroscopic portal has not being sufficiently described. Here, we describe a case of acute acromioclavicular dislocation grade III. The arthroscopic stabilisation was achieved using the TightRope (Arthrex, Naples, USA) implant. Through this technique, the approach to the articular portion of the coracoid process can be made intra-articularly or from the subacromial space. We accessed intra-articularly, by opening the rotator interval to reach the coracoid process from the joint cavity. After opening the rotator interval, an ectopic insertion of the pectoralis minor was observed. The choice of approach of the coracoid process from the subacromial space would have complicated the intervention, making it necessary to sever the ectopic tendon to complete the technique, lengthening the surgical time and increasing the chance of complications. For this reason, the use of a standard posterior portal providing intra-articular arthroscopic access through the rotator interval is recommended since the aforementioned anatomical variation is not infrequent. Level of evidence Therapeutic studies-investigating the results of treatment, Level V.

Inter- and intraobserver reliability of the Rockwood classification in acute acromioclavicular joint dislocations.

PURPOSE: The reliability of the Rockwood classification, the gold standard for acute acromioclavicular (AC) joint separations, has not yet been tested. The purpose of this study was to investigate the reliability of visual and measured AC joint lesion grades according to the Rockwood classification. METHODS: Four investigators (two shoulder specialists and two second-year residents) examined radiographs (bilateral panoramic stress and axial views) in 58 patients and graded the injury according to the Rockwood classification using the following sequence: (1) visual classification of the AC joint lesion, (2) digital measurement of the coracoclavicular distance (CCD) and the horizontal dislocation (HD) with Osirix Dicom Viewer (Pixmeo, Switzerland), (3) classification of the AC joint lesion according to the measurements and (4) repetition of (1) and (2) after repeated anonymization by an independent physician. Visual and measured Rockwood grades as well as the CCD and HD of every patient were documented, and a CC index was calculated (CCD injured/CCD healthy). All records were then used to evaluate intra- and interobserver reliability. RESULTS: The disagreement between visual and measured diagnosis ranged from 6.9 to 27.6 %. Interobserver reliability for visual diagnosis was good (0.72-0.74) and excellent (0.85-0.93) for measured Rockwood grades. Intraobserver reliability was good to excellent (0.67-0.93) for visual diagnosis and excellent for measured diagnosis (0.90-0.97). The correlations between measurements of the axial view varied from 0.68 to 0.98 (good to excellent) for interobserver reliability and from 0.90 to 0.97 (excellent) for intraobserver reliability. CONCLUSION: Bilateral panoramic stress and axial radiographs are reliable examinations for grading AC joint injuries according to Rockwood's classification. Clinicians of all experience levels can precisely classify AC joint lesions according to the Rockwood classification. We recommend to grade acute ACG lesions by performing a digital measurement instead of a sole visual diagnosis because of the higher intra- and interobserver reliability. LEVEL OF EVIDENCE: Case series, Level IV.

Acute traumatic posterior shoulder dislocation.

Posterior shoulder dislocation occurs rarely and is challenging to manage. The mechanisms of trauma are varied, which complicates diagnosis. Missed or delayed diagnosis and treatment can have serious deleterious effects on shoulder function. All cases of suspected posterior shoulder dislocation require a high level of suspicion and appropriate imaging. Identification of associated injuries, such as fractures and rotator cuff tears, is important to guide treatment. In the acute setting, most patients are treated with closed or open reduction with additional soft-tissue or bony procedures. Patients treated in a delayed fashion for persistent instability may require additional procedures, including arthroplasty.

Luxação acrômioclavicular / Acromioclavicular luxation

A articulação acrômio clavicular faz parte do conjunto anatômico que compõe o ombro. Ela é responsável pela estabilização e junção do esqueleto apendicular superior ao axial. Lesões traumáticas ou crônicas desta articulação levam a perda de função do membro superior. Lesões do tipo luxação nesta articulação representam 15% das luxações do ombro. A incidência desta patologia pode estar subestimada devido à parcela de pacientes que apresentam a patologia após o trauma e não procuram emergência médica ou consultas para diagnostico.

From the anatomical point of view, the acromioclavicular joint is part of the shoulder. It is responsible for the stabilization of the shoulder and it is the junction between the axial skeleton and the superior appendicular skeleton. Traumatic or chronic lesions of this joint can lead to important restriction of function. Acromioclavicular dislocation represents 15% of shoulder dislocations. The incidence of this pathology could be underestimated because a large parcel of patients do not seek emergencies for treatment at the time of the injury leaving the pathology undiagnosed.