Acromial Fracture Associated with Coracoid Fracture Not Belong to Floating Shoulder : A Case Report

Floating shoulder is no osseoligamentous connection between the humeral shoulder joint with the axial skeleton. The osseoligamentous of shoulder joint connection compose a ring, including clavicle,acromion, coracoid, glenoid fossa, surgical or anatomical scapula neck, acromioclavicular ligament and coracolclavicular ligament. This ring is known as superior shoulder suspensory complex (SSSC). The double disruptions of this ring are recognized to create a potentially unstable anatomical situation. Thus, oating shoulder is also characterized as double or more disruptions of SSSC. Surgical reduction and xation for the displacement of those fractures at one or more sites is recommended in previous reports. We present 2 cases of patients with acromial and coracoid displaced fractures which belong to a type of the double disruptions of SSSC, there were still osseoligamentous connection between the humeral shoulder joint with the axial skeleton. The patient’s shoulder function after nonoperative management was satisfactory.


Introduction
The oating shoulder is the most complex injury of shoulder girdle, which involves all anatomical structures of the shoulder joint (1)(2)(3). The de nition of oating shoulder is the scapula neck fracture combined with the clavicular or acromioclavicular fracture, or the acromioclavicular dislocation, or the rupture of the coracoclavicular and coracoacraomial ligament. In short, oating shoulder is no osseoligamentous connection between the humeral shoulder joint with the axial skeleton (4). To better understand the characteristics of shoulder girdle, some studies proposed the theory of the superior shoulder suspensory complex (SSSC) which including clavicle, acromion, coracoid, glenoid fossa, scapula neck, acromioclavicular ligament and coraclclavicular ligament (5). Any double or more disruptions of SSSC creates a unstable anatomical situation in injured shoulder (1). However, the de nition and classi cation of oating shoulder and double disruptions of SSSC remains fully unclear, which leads the treatment of that is controversial (1,6,7). Double disruptions of SSSC are only need to xation one site theoretically (5,6). Moreover, some of doctors recommended surgery to both fractures sites of oating shoulder, and proposed that the prognosis of operative treatment is signi cantly better than nonoperative management(8-10). Therefore, speci c types of clinical cases may help to explain this issue. We present 2 case of acromial with coracoid displaced fractures, which belong to a type of the double disruptions of SSSC but not be categorized as oating shoulder.

Case 1 Presentation
A 27 years old man was transferred to our hospital, who complain the pain and dysfunction of right shoulder and arm. He had met with a road tra c accident 11 days ago and sustained fracture of right humeral shaft, multiple ribs fractures (right 1-6 ribs), acromial and coracoid fracture of the right side (Fig. 1A). He had stable autonomous respiration, physical examination revealed pain, swelling, and restriction of movements of right shoulder and arm, no neurovascular injury. He was temporary xed with plaster and sling and accepted CT scan. Radiographs views showed coracoid fracture (Ogawa Type I, Eyres type V) (Fig. 1B), acromial fracture (Ogawa Type II) (Fig. 1C) and humerus shaft fracture (AO 12-B2). Displaced fractures of shoulder were belonging to double disruptions of SSSC. This patient was a truck driver, who needed an earlier return to normal shoulder function. We did the surgical intervention after 14 days from the date of the trauma. Firstly, this patient was given general anesthesia and positioned in supine position. The shaft fracture of his humerus was reduced and then xed with a locking plate through the anterolateral approach. After that, this patient was changed to the lateral decubitus position on the healthy side. The open reduction of acromial fracture was achieved through the superior approach. Acromial fracture was easily reduced and xed by an anatomical plate. Subsequently, an expose of coracoid fracture was achieved by modi ed deltopectoral approach and fracture was xed by two cancellous screws (Fig. 1D). The patient was immobilized in broad arm sling for 3 weeks while allowing active hand and wrist movements. 3 weeks after surgery, intermittent pendulum exercises and passive mobilization were started.8 weeks after surgery, active shoulder mobilization and rotator cuff strengthening exercises were performed. At the 6 months after injury, the patient had painless full shoulder movement, Shoulder and Hand (DASH(11)) questionnaire recorded 6.7 and Constant (Murley)score CS (12)   injuries which should be non-operative (Fig. 3A). Acromial part disruption with coracoid part disruption of SSSC (double disruptions without neck fracture)are considered Type B injuries whose surgical indications are still controversial (Fig. 3B). Floating shoulder (double disruptions including neck fracture)are classi ed as Type C injuries which need surgery (Fig. 3C).
Coracoid fracture usually xed with screws, and there was no gold standard to x single acromial fractures or multiple scapular fractures (13). There were a variety of xation techniques for single acromial fractures including K-wire xation, tension band wiring, screw xation and plate xation. In case1, anatomical plate for acromial fracture was selected to provide stability. First step of our surgery was the management of acromial fracture, because the surgical exposure and reduction are more easier than operation of coracoid fracture. During the operation, we found that when anatomic reduction of acromial fracture was achieved, the reduction of coracoid fracture can be performed easily. On the other hand, nonoperative management of shoulder fracture includes pain control and sling for 6 weeks. 6 weeks after injury, intermittent pendulum exercises and passive mobilization were started. 2 mouths after injury, active shoulder mobilization exercises and rotator cuff strengthening exercises were performed.
System review of oating shoulder shows that prognosis of patients with surgery is better than those with nonoperative management. However shoulder function of our cases were satisfactory no mater surgery or nonoperative management. Shoulder function of case 1 with surgery was better than shoulder function of case 2 with nonoperative management at the early stage. But at the end of follow up, shoulder function of both cases were satisfactory. Surgery is bene cial only for rapid recovery of shoulder function.
Unfortunately, scapula fractures were accounting for 1% of all fractures, acromial with coracoid Fracture more rarely. Westphal T reported only 5 cases in 5 years (between 2009 and 2014) (14). In our trauma centre acromial fracture with coracoid fracture without other SSSC disruption were 1.7% of all scapular fractures (2 0f 117 shoulders)in two years(between December 2016 to December 2018). More cases will needed to show more clinical features of this type of injury.

Declarations i. Funding
This research has received no speci c grant from any funding agency in the public, commercial, or notfor-pro t sectors.
ii. Con icts of interest/Competing interests (include appropriate disclosures) All authors have disclosed no con ict of interest.
iii. Ethics approval (include appropriate approvals or waivers) This clinical study is a retrospective study, which only collects the clinical data of patients, does not interfere with the treatment plan of patients, and will not bring physiological risks to patients. All data and gures were obtained in accordance with ethical requirements according to the ethical guidelines of the Helsinki Declaration. Written informed consent was obtained from individual or guardian participants.
iv. Consent to participate (include appropriate statements) Written informed consent was obtained for each participant according to federal and institutional guidelines.
v. Consent for publication (include appropriate statements) Written informed consent for publication was obtained from all participants.
vi. of data and material (data transparency) All data generated or analysed during this study are included in this published article vii. Code availability (software application or custom code) Not applicable.

viii. Authors' contributions
All persons who meet authorship criteria are listed as authors, and all authors certify that they have participated su ciently in the work to take public responsibility for the content, including participation in the concept, design, analysis, writing, or revision of the manuscript. Each author certi es that this material or part thereof has not been published in another journal, that it is not currently submitted elsewhere, and that it will not be submitted elsewhere until a nal decision regarding publication of the manuscript.
Indicate the speci c contributions made by each author.  A patient with acromial and coracoid fractures was given surgery. The 27 male was treated with osteosynthesis of the right scapula after a road tra c accident. At the 6 months after injury, the patient had painless full shoulder movement. At the end of follow up (29 mouths after injury), the patient only complained uncomfortable when he sleep on the right side, but not regularly. A Preoperative X-ray of his  The patient with acromial and coracoid displaced fractures was given non-operative management. A 87 male was met with a road tra c accident and sustained a acromial and coracoid fractures. He was treated with pain control and sling for 6 weeks. Passive mobilization exercises were started in the 6 weeks. Active and strengthening exercises were performed in 2 mouths after injury. At 3 months after injury, the patient was obviously limited at elevation, external and internal rotation. After continuous exercise, the shoulder function gradually improved. At the end of follow up (29 mouths after injury),the  Classi cation of Scapula fracture without articular cartilage injury. A Single disruption or no disruption of SSSC are classi ed as type A injuries which should be non-operative. B Double disruptions of SSSC without neck fracture (acromial part disruption with coracoid part disruption) are classi ed as type B injuries whose surgical indications are still controversial. C Double disruptions including neck fracture ( oating shoulder) are classi ed as type C injuries which need surgery.