summary Scapula Fractures are uncommon fractures to the shoulder girdle caused by high energy trauma and associated with pulmonary injury, head injury, and increased injury severity scores. Diagnosis can be made with plain radiographs and CT studies are helpful for fracture characterization and surgical planning. Treatment is usually nonoperative with a sling. Surgical management is indicated for intra-articular fractures, displaced scapular body/neck fractures, open fractures, and those associated with glenohumeral instability. Epidemiology Incidence rare <1% of all fractures 3-5% of shoulder girdle fractures Demographics age commonly between 25-50 males > females Location scapular body/spine = 45-50% glenoid = 35% glenoid neck = 25% glenoid fossa/rim = 10% often associated with impaction of humeral head into glenoid acromion = 8% coracoid = 7% Etiology Pathophysiology mechanism of injury high-energy trauma (80-90%) motor vehicle collisions account for >70% of scapula fractures indirect trauma through fall on outstretched hand glenohumeral dislocation anterior dislocation leads to anterior rim fracture posterior dislocation leads to posterior rim fracture seizure electric shock Associated injuries (in 80-95%) medical thoracic injury (80%) hemothorax/pneumothorax (>30%) pulmonary contusion (>40%) head injury (35-50%) orthopaedic rib fractures (53%) ipsilateral extremity injury (50%) ipsilateral clavicle fractures (25%) spine fracture (26-30%) pelvic ring/acetabular fractures (15%) scapula fracture is important predictor upper extremity vascular injury (11%) subclavian and axillary arteries at risk higher risk with scapulothoracic dissociation brachial plexus injury (5-13%) 75% of brachial plexus injuries resolve complete brachial plexus injuries less likely to resolve Anatomy Osteology scapular body origin or insertion of 18 muscles function to connect scapula to thorax, spine and upper extremity large triangle shape with 4 major processes scapular spine osseous bridge separating supraspinatus and infraspinatus spinoglenoid notch represents possible site of compression for suprascapular nerve glenoid represents articulating process on lateral scapula serving as socket for glenohumeral joint pear-shaped and wider inferiorly from anterior to posterior average 1-5º of retroversion and 15º superior tilt from scapular plane fibrocartilaginous labrum deepens glenoid fossa by 50% to increase stability acromion articulates with clavicle to form acromioclavicular joint formed by 3 ossification centers pre acromion - tip meso acromion - mid meta acromion - base coracoid process has two secondary ossification centers that are open until around age 25 and should not be interpreted as fracture angle of coracoid tip of coracoid muscular attachments conjoint tendon coracobrachialis short head biceps pectoralis minor ligament attachments coracoclavicular (CC) ligaments most anterior CC ligament attachment is 25mm from tip of coracoid coracoacromial ligament Arthrology glenohumeral joint glenoid & labrum support humeral head to produce high degree of motion stability provided by static and dynamic stabilizers scapulothoracic joint not a true joint but does represent an articulation between scapula and thorax involved primarily in elevation and depression of shoulder as well as rotation and pro-/retraction acromioclavicular (AC) joint articulation of acromion and distal clavicle supported by acromioclavicular ligaments (horizontal stability) and coracoclavicular ligaments (vertical stability) 8º of rotation occurs through acromioclavicular joint superior shoulder suspensory complex bone & soft tissue ring which provides connection of glenoid/scapula to axial skeleton composed of 4 bony landmarks distal clavicle acromion coracoid glenoid also composed of ligamentous complexes of acromioclavicular and coracoclavicular joints Blood supply contributions from anterior and posterior circumflex, scapular circumflex and suprascapular arteries watershed area present in anterosuperior glenoid Nervous system scapula is intimately associated with brachial plexus axillary nerve is at risk inferior to the glenoid as it runs from anterior to posterior compression of suprascapular nerve at scapular notch leads to supraspinatus/infraspinatus weakness, with compression at the spinoglenoid notch leading only to infraspinatus weakness Biomechanics scapula contributes to glenohumeral rotation and abduction 1/3 of shoulder motion is scapulothoracic, 2/3 is glenohumeral Classification Classification is based on the location of the fracture and includes scapular body fractures usually described based on anatomic location scapular neck fractures look for associated AC joint separation or clavicle fracture if occuring together, known as "floating shoulder" glenoid fractures Ideberg classification with Goss modification (below) low inter- and intra-observer reliability and questionable association with management AO-OTA classification more reliable in diagnosis than Ideberg classification acromial fractures Kuhn classification coracoid fractures Ogawa classification - based on fracture proximity to CC ligaments Eyres classification scapulothoracic dissociation Ogawa Coracoid Fracture Classification Type I Fracture occurs proximal to the coracoclavicular ligament Type II Fracture occurs towards the tip of the coracoid Kuhn Acromial Fracture Classification Type I Nondisplaced or minimally displaced Type II Displaced but does not compromise the subacromial space Type III Displaced and compromises the subacromial space Ideberg Classification of Glenoid Fracture Type Ia Anterior rim fracture Type Ib Posterior rim fracture Type II Fracture line through glenoid fossa exiting scapula inferiorly Type III Fracture line through glenoid fossa exiting scapula superiorly Type IV Fracture line through glenoid fossa exiting scapula medially through body Type Va Combination of types II and IV Type Vb Combination of types III and IV Type Vc Combination of types II, III, and IV Type VI Severe comminution AO Classification for Glenoid Fractures Fracture type Subtype Qualification 14F0: Extra-articular Glenoid neck 14F1: Simple, intra-articular 1.1: anterior glenoid rim 1.2: posterior glenoid rim 1.3: transverse/short oblique f: infraequitorial, single quadrant r: supraequatorial, 2 quadrants t: infraequitorial, 2 quadrants i: infraequitorial e: equitorial p: supraequitorial 14F2: Multifragmentary 2.1: >= 3 articular fragments 2.2: central fracture-dislocation 14B: Extension into body 1: exits body at <=2 points 2: exits body at >=3 points presentation History traumatic direct blow to shoulder or fall on outstretched arm scapula fracture may be missed or diagnosed late in presence of other distracting, traumatic injuries Symptoms diffuse, severe shoulder pain systemic symptoms shortness of breath chest wall pain Physical exam inspection tenderness to palpation shoulder diffusely inaccurate in determining specific location of fracture clavicle spine rib cage evaluate for abnormal shoulder contour compared to contralateral site look for open wounds or abrasions soft tissue swelling may be significant motion acute active range of motion testing not recommended likely to cause unnecessary pain gentle passive range of motion can be useful in noting any blocks to motion neurovascular check motor and sensory function of nerves at risk axillary radial median ulnar confirm symmetry of extremity pulses to contralateral side Imaging Radiographs recommended views true AP, grashey AP, scapular Y and axillary lateral view AP chest radiograph evaluate for pneumothorax evaluate for widening of space between medial scapular border and spine >1 cm indicates possible scapulothoracic dissociation measurements intra-articular step-off lateral border offset (medialization) glenopolar angle (measured on grashey AP) angle connecting superior/inferior scapula and lateral border of scapula normal considered 30-45º scapular angulation best seen on scapular Y radiograph CT indications intra-articular fracture significant displacement >1cm may also help detect other thoracic/spine injuries views three-dimensional reconstruction better demonstrates fracture patterns coronal and axial views useful to evaluate displacement, intra-articular step-off and medialization of glenoid sagittal view useful to evaluate anterior-posterior displacement and angulation MRI indications not regularly obtained but may be useful in some cases to evaluate the superior shoulder suspensory complex for ligamentous injury differential Os Acromiale unfused secondary ossification centers (meso- and meta-acromion) associated with impingement and rotator cuff symptoms and may be detected incidentally with trauma Treatment Nonoperative sling for 2-3 weeks, followed by early motion scapular body fractures indications indicated for vast majority of scapula fractures 90% are minimally displaced and acceptably aligned outcomes progressive deformity/displacement is possible during first 3 weeks recommend serial weekly radiographs during this time those associated with multiple underlying rib fractures or superior shoulder suspensory complex disruptions are more likely to displace union at 6-8 weeks in most cases most recover near-normal function attributed to shoulder's capability for compensatory motion poorer outcomes noted in patients with glenopolar angle <20º scapular neck fractures indications translation <1 cm angulation <40º glenopolar angle >20º no additional injury to superior shoulder suspensory complex outcomes true outcomes not well established some reports of unsatisfactory results in ~30% of cases treated nonoperatively, while others note equivalent outcomes to surgical fixation intra-articular glenoid fractures indications <4 mm step-off and less than 25% glenoid involvement outcomes with small fractures and minimal intra-articular step-off, nonoperative management results in excellent functional outcomes risk of instability exists in rim fractures with larger degree of articular surface involvement acromion fractures indications displacement <1 cm and no additional injury to superior shoulder suspensory complex outcomes good outcomes with Kuhn type I and II fractures which do not compromise subacromial space coracoid fractures indications displacement <1 cm and no additional injury to superior shoulder suspensory complex coracoid tip fractures distal to insertion of coracoclavicular (CC) ligaments, even if displacement is >1 cm (Ogawa II) outcomes good results and motion with both type I and II fractures meeting indications Operative open reduction internal fixation indications (most are relative) open fracture scapular body fractures medialization of lateral border > 20 mm glenopolar angle < 20-22º angulation > 40º combination of medialization >15 mm and angulation >35º scapular neck fracture angulation > 40º translation > 1 cm glenopolar angle < 20-22º "double disruption" of the superior shoulder suspensory complex (floating shoulder) indicates unstable nature of bony/ligamentous ring intra-articular glenoid fracture > 20-25% anterior or posterior glenoid involvement with subluxation of humerus can cause persistent glenohumeral instability articular step-off > 4 mm acromion fracture displacement > 1cm painful nonunion subacromial impingement double disruption of superior shoulder suspensory complex coracoid fracture displacement > 1 cm painful nonunion ipsilateral scapula fracture requiring fixation Ogawa type I coracoid fracture extending into scapular body double disruption of superior shoulder suspensory complex techniques screw(s) percutaneous vs. open plate(s) + screws(s) arthroscopic-assisted suture anchor repair vs. percutaneous screw fixation useful in anterior/posterior glenoid rim fractures outcomes scapular body fractures most return to having near-normal strength and symmetric range of motion scapular neck fractures good shoulder function and high union rates complication rates up to 15% intra-articular glenoid fractures good to excellent subjective outcomes (pain, strength, and motion) in 80-95% of patients higher rate of poor outcomes with concomitant chest and neurologic trauma coracoid/acromion fractures good outcomes in >85% of cases high rates of union and full range of motion some risk exists for requiring hardware removal Techniques Nonoperative (immobilization) noninvasive but can lead to stiffness technique sling immobilization for 2-3 weeks Open Reduction Internal Fixation (ORIF) scapular body/neck fractures approaches straight posterior overlying glenohumeral joint indicated in isolated displaced fractures scapular neck lateral scapular border less extensile than Judet approach Judet approach indicated if multiple scapular borders need to be accessed incision courses along spine of scapula and angles down vertebral scapula border in "L" shape utilizes internervous plane between infraspinatus (suprascapular nerve) and teres minor (axillary nerve) technique can use 2.7 mm or 3.5 mm plates locking plate technology may be advantageous given thin scapular bone, especially along vertebral border reconstruction plates can be contoured around scapular spine and superomedial angle of scapula complications neurovascular injury malunion hardware failure intra-articular glenoid fractures approaches deltopectoral approach utilizes intermuscular plane between deltoid (axillary n.) and pectoralis major (medial/lateral pectoral n.) indicated in fractures involving anterior glenoid with inferior extension (Ideberg II) in cases of medial/inferior fracture extension into scapular body, posterior approach may be necessary can be extended proximally to clavicle in cases where superior glenoid fracture extends to coracoid posterior approach (detailed above) displaced posterior glenoid rim fractures with intra-articular involvement intra-articular glenoid fractures with inferior or medial extension into body not accessible anteriorly lateral midaxial approach incision just caudal to axilla in order to access inferior glenoid fractures easier ability to instrument along inferior scapular neck techniques percutaneous fixation if hardware is inserted percutaneously, arthroscopic assistance may be beneficial to ensure articular reduction suture anchors can be used to advance labrum in cases of small bony defects screw fixation can be used to fixate larger bony rim fragments minifragment fixation recommended in most cases open fixation inferior glenoid fractures may be fixed with plate/screw(s) in buttress fashion complications post-traumatic arthritis subscapularis failure if anterior approach requires subscapularis take-down recurrent glenohumeral instability acromion fractures approach vertically based posterior incision centered over the scapular spine and posterior acromion dissection taken down to deltoid and trapezius muscles and reflected off the scapular spine and posterior acromion technique proximal acromial fracture 2.7 or 3.5 mm lag screws placed perpendicular to fracture site if possible 2.4 or 2.7 mm reconstruction plate placed to neutralize fracture distal acromial fracture bone is very thin in this area plate fixation may be difficult to obtain, although 2.0mm mini-fragment plate can function well tension band technique can be considered complications hardware irritation/failure coracoid fractures approach deltopectoral approach (detailed above) retractor placed at base of coracoid to visualize fracture technique can carefully remove portion of the coracoacromial ligament and pectoralis minor attachment to better visualize the fracture bed provisionally pin the coracoid with 1-2 Kirschner wires fixation achieved with 1-2 bicortical 2.7 or 3.5 mm screws +/- washers may also place quarter tubular buttress plate if needed increased risk of requiring hardware removal rarely, in Ogawa type II fractures requiring intervention, suture anchor can be placed in fracture bed and tip can be captured using a suture lasso technique complications neurovascular injury hardware irritation complications Post-traumatic glenohumeral arthritis risk factors intra-articular glenoid fracture with residual step-off/displacement treatment conservative management NSAIDs, therapy, injections shoulder arthroplasty (total vs. reverse) Malunion risk factors higher degree of angulation, translation or medialization more likely with nonoperative management questionable effect on shoulder function treatment typically nonoperative depending on location of fracture and degree of deformity If deformity involves glenoid, may be correctable with reverse total shoulder arthroplasty Recurrent glenohumeral instability risk factors younger patients larger degree of bone loss (anterior or posterior) treatment bony fixation (open or percutaneous) arthroscopic vs. open suture anchor repair with labral advancement more useful for smaller bony fragments which are not able to be fixated otherwise Neurovascular injury risk factors scapulothoracic dissociation iatrogenic injury during surgical dissection deltopectoral approach musculocutaneous n. axillary n. posterior/judet approach axillary n. suprascapular n. circumflex scapular v. posterior humeral circumflex v. treatment nerve injury after scapulothoracic dissociation EMG 3-6 weeks after injury to assess extent of injury and degree of recovery iatrogenic neurovascular injury direct repair if possible