12.36 Fractures and dislocations of the shoulder girdle

The shoulder girdle is a complex structure of three bones and five articulations that aims to position and support the function of the hand in space. As all joints, in order to serve the end-organ effectively the girdle requires range of motion, stability, and strength. Complex movement is shared amongst the five articulations resulting in a particular pattern of motion known as shoulder rhythm. In theory any pathology that affects these elements of girdle function may result in disability; however, as functional demands vary amongst patients and segmental disability may be compensated by the function of neighbouring joints, measurable deficits do not always correspond to functional disability. It is likely that in the average individual loss of 20% of girdle motion will not result in disability.

The glenohumeral articulation is universal joint. In order to allow this range the joint depends less on osseous contact and stability relies more on the intra-articular and periarticular soft tissues. The structural and functional components of the glenohumeral joint (GHJ) stability have been extensively studied. The structures contributing to the joint stability are shown in Table 12.36.1.

The labrum provides a 50% increase in the congruency of the glenohumeral articulation whilst the middle and inferior glenohumeral ligaments are the primary ligamentous stabilizers of the joint.

A variety of traumatic lesions corresponding to the vector of the dislocation have been identified. The classic Bankart lesion associated with anterior dislocations represents the detachment of the capsulolabral complex from the anteroinferior portion of the glenoid. Correspondingly the Hill Sachs is an impaction fracture of the posterior part of the humeral head. Common fracture of the anteriorly dislocated shoulder is an impaction fraction of the glenoid with the great tuberosity fracture the next most common. Shearing fractures of the glenoid rim are discussed in the section on scapular fractures.

In posterior dislocations the impaction fracture is in the anterior part of the head (reverse Hill Sachs) and may be associated with avulsion of the lesser tuberosity or the subscapularis tendon.

Aging of musculoskeletal system results in inelastic tissues. Whilst fractures are more common in young adults, rotator cuff injuries have been identified in up to 85% of patients over 40 years of age. The presence of massive rotator cuff tears affects the outcome of shoulder dislocations.

Anterior dislocation of the GHJ is the most common joint dislocation with a prevalence of 1.7%. It most commonly occurs as a sport related injury in young males and after a fall in elderly females. Posterior dislocation accounts for 2% of the GHJ dislocations. With the higher prevalence of high-energy injuries such as motorcycle crashes dislocations of the GHJ occur in conjunction with proximal humerus fractures (PHF). The obvious fracture and the difficulty of obtaining adequate imaging may result in a missed dislocation.

The history and clinical appearances are pathognomonic of the anterior dislocation of the GHJ. Caution is required in circumstances where the history is unclear or other clinical pathologies such epilepsy prevail. In contrast with the young adult the history of injury in the elderly can be vague, the complaints minor and the appearances subtle. Hence the diagnosis may be delayed or even missed.

Essential part of the clinical examination prior to any reduction manoeuvres is the neurological status of the arm. In anterior dislocation the axillary nerve is often involved although a recent study suggested a significant incidence of nerve involvement up to 48% when electromyographic (EMG) studies were used as a diagnostic tool. Multiple neural structures can be affected; however, the long-term prognosis is good with recovery evident 12–45 weeks following the injury.

Plain radiographs in two planes are the minimum standard of care regarding the imaging of the injury. Poor imaging may lead to error in diagnosis and management. The anteroposterior view must be in the plane of the GHJ. Axial views are difficult due to pain, however adequate analgesia and skilled radiography will produce adequate views in almost all circumstances. The direction and associated osseous injuries must be considered. The documentation of the dislocation is of importance in the long term in order to differentiate individuals with unidirectional traumatic dislocation from patients with multidirectional instability.

A multitude of reduction techniques have been describe for reduction of the anterior GHJ, the Hippocratic one being the oldest described. The principle of reduction, however, remains the same: adequate analgesia and monitored sedation followed by disimpaction, controlled traction, and reduction of the joint. Techniques that do not involve physicians in the process, such as the prone position and over the chair traction with weight application, are preferable. Contraindication to reduction in the emergency department is the dislocation with an undisplaced fracture of the humeral neck. Dislocations of the GHJ associated with humeral neck fractures are rarely successful in the Emergency Department and best avoided as the repeated trauma during the attempts may lead to a variety of complications and affect outcome.

Debate exists regarding the of postreduction after care. Multiple studies suggest no difference in the incidence of recurrent instability with or without immobilization in a sling and swathe or Velpeau bandage. An elegant study demonstrated that the avulsed capsuloligamentous flap (Bankart lesion) is best apposed to the glenoid neck with the arm in external rotation. However, the application of the finding in clinical practice has yet to be tested. Whilst the early surgical intervention has been lingering for some time, a recent well-structured study from Edinburgh suggested that early arthroscopic Bankart repair significantly decreases the risk of redislocation within the first 2 years in young individuals (15–27 years).

It is hardly surprising that the redislocation is likely to occur in the ‘sportingly active’ group as the injury is sports related and they are unwilling to modify their activity. Multiple studies confirmed the fact and demonstrated a significant risk of up to 55% in the 2 years increasing to 66.8% at 5 years for the 15–27 age group.

Whilst recurrent dislocation is the most common injury-related complication in the young, the presence of rotator cuff damage and/or glenoid rim fracture predispose to redislocation of the GHJ in the elderly within the first 6 weeks. Pathognomonic of postreduction incongruence of the GHJ is painful rotation: in almost all non-fractured dislocations, rotation with the humerus in neutral position is comfortable and well tolerated. In the incongruent GHJ rotation is invariably limited and associated with pain and occasional crepitus.

Fracture dislocations can pose significant dilemmas and can be challenging to treat operatively. Reduction and fixation in young adults is preferable whilst in the elderly and low-demand patients with poor bone stock shoulder hemiarthroplasty may be the better option. Fractures of the greater tuberosity usually reduce once the GHJ is congruent. Displacement of the tuberosity fragment may occur, possibly suggesting associated rotator cuff tear. Early recognition will result in easier reconstruction and better outcome in terms of range of GHJ motion.

At the proximal end of the humerus the anatomical neck at 45 degrees to the shaft leads to the head that carries the head in average of 20 degrees of retroversion. The rotator cuff attaches to the great tuberosity that is on average 8mm lower than the edge of the articular surface. The bicipital groove allows the uninterrupted and smooth function of the long heads of the biceps. Medial to the groove the subscapularis attaches to the lesser tuberosity. Studies have demonstrated that the vascular supply to the head is via four routes (Figure 12.36.2 and Box 12.36.2). Fractures through the anatomical neck of the humerus may have a significant risk of avascular necrosis (AVN) whilst fractures through the surgical neck will spare the blood supply to the head.

Proximal humeral fractures are common, compromising 5% of all fractures. It is a spectrum of injury ranging from physeal Salter–Harris II fracture in adolescents with excellent prognosis to high-energy fractures in young adults usually as the result of motor vehicle crashes. However, the majority of fractures occur in the seventh decade of life with a reported incidence of 63/100 000 population at an average age of 64.8 years. Fractures of the proximal humerus are now considered as ‘fragility fractures’.

The mechanism of injury is indirect force with fall on the arm or direct blow to the shoulder. The position of the arm, energy transfer upon impact and the bone stock will result in abduction, or abduction fracture patterns with or without dislocation of the GHJ.

Codman in 1934 described a distinct pattern of fracture of the proximal humerus and his observation remains valid to date: the proximal humerus fails in a predictable pattern due to the vector of force and the attachments of the musculotendinous units. The result is a fracture of the greater tuberosity, fracture of the lesser tuberosity and a fracture through the humeral neck. Neer’s classification (Figure 12.36.3) is based on Codman’s observations and despite criticism and individual interpretation it is still widely used providing a useful template for planning treatment. It classifies fractures according to the number of displaced fragments. Displacement was defined as 1cm and/or 45-degree angulation. This has led to fierce debate especially regarding the fractures involving the greater tuberosity (GT). Current thinking accepts displacement of no more of 5mm when referring to GT fractures. Evolution of knowledge resulted in recognition that valgus four-part fractures carry a different prognosis due to preservation of the head vascularity. Using Neer’s criteria, 80% of PHF are undisplaced and require symptomatic treatment followed by an intensive and structured rehabilitation programme.

The AO/OTA comprehensive classification is a useful system and distinguishes between extra articular, partial intracapsular, and intracapsular fractures.

Clinical assessment should document the neurovascular status and the condition of the soft tissues.

Adequate imaging is essential to identify the extent of the fracture, the fracture pattern, and the state of the GHJ and neighbouring joints. Whilst most information can be obtained by adequate good quality plain radiographs, in patients were intervention may be appropriate, computed tomography (CT) of the proximal humerus with reformatted images has become the standard of care.

Patient particulars are of essence to complete the assessment prior to any decision regarding the treatment of the fracture (Box 12.36.3).

The most common complication of PHF is stiffness. As the GHJ heavily relies on the surrounding soft tissue structures for its function, early range of motion is of absolute essence in whatever method of treatment is followed.

GT fractures displaced more than 5mm are associated with rotator cuff tear and as such are potentially unstable fractures. Furthermore displacement may result in malunion and lead to impingement. However, the majority of the GT fractures displace superioposteriorly and as such result in an inefficient pulley mechanism resembling massive rotator cuff tear. Hence it is recommended that fractures of the GT displaced more than 10mm are best treated by reduction and fixation. Fractures displaced 5mm should be investigated for an associated tear at the interval. Repair is recommended if a tear is identified.

Displacement of the articular fragment (Figure 12.36.4) resulting in translation of the centre of GHJ rotation may affect the efficiency of the lever system. Correction of the head glenoid relationship restores the centre of rotation and minimizes the risk of pulley inefficiently.

High-energy fractures with or without dislocation in young adults is best treated with reconstruction of the proximal humerus and attachment of the tuberosities. It is postulated that replacement surgery of the humeral head with healed tuberosities is a more predictable procedure than primary replacement of a fracture dislocation that is associated with poor rotator cuff function and severe stiffness.

Fractures of the surgical neck and the metaphysis are usually undisplaced and the fracture configuration allows early mobilization. Widely displaced fractures are unstable; the distal fragment buttonholes through the muscles and may go on to a non-union (Figure 12.36.5). Fractures of the proximal humerus that require manipulative reduction are inherently unstable.

Displaced fractures of the proximal humeral third extending in the metaphyseal region are often unstable injuries associated with high incidence of delayed union/non-union. This appears to be especially true when patients report excessive clicking at the fracture site. Low energy fractures are associated with large soft tissue interposition whilst high-energy injuries result in medial and lateral fragmentation and subsequent gross displacement due deforming forces from the muscle, weight of the arm, and body habitus. These are best treated operatively at the onset (Figure 12.36.6).

Sophistication of knowledge has led to less dogmatic approaches when it comes to fracture treatment. Most injuries can be treated non-operatively with acceptable results. Significant injuries will do badly whatever the intervention. It is the role of orthopaedists to identify the patients that appropriate operative treatment will affect the final outcome. Table 12.36.2 may act as an aid to decision-making.

Historically, operative repair of PHF was associated with myriads of complications:

Complex fractures, poor imaging, poor understanding of the objectives of treatment, poor bone stock, unfamiliar territory, little experience, inadequate implants were some of the contributing factors that gave operative fixation of the PHF bad reputation. The good news is it could only get better: whilst operative treatment of these injuries remains a challenge some of the factors mentioned are better understood. Due to small numbers of operative cases and variance of patient and injury characteristics it is difficult for the case series reported in the literature to be didactic and help the orthopaedic surgeon decide on the treatment modality.

Evolution of medical technology in imaging and multidisciplinary care of the frail patients has improved the patients’ selection for operative treatment. The development of new plating systems to address the issues of osteopenic bone and fragmentation most often encountered in treatment of the PHF can only be seen as an advantage. However, the new technology is not a panacea and has not altered the indications for surgical treatment. In this context poor patient selection will result in relatively large treatment related complications.

The operative options are reduction and fixation and arthroplasty. The aim of reduction and fixation is to restore anatomy whilst preserving the blood supply to the bone and create a stable construct to allow early range of motion. Patients will need to follow a structured rehabilitation programme and the fracture will need to heal. There are technical issues relating to fragmentation and bone stock. Results are dependant on patient selection and surgeons’ experience.

Hemiarthroplasty for PHF was recommended by Neer as the outcome following treatment of four part fractures was poor. Stableforth confirmed that the procedure was reliable, providing a pain-free shoulder at the expense of movement. Whilst there has been some understanding and improvement on technical aspects, length of the prosthesis appears still to be an issue with approximately 50% being too long or too short resulting in eccentric centre of rotation of the GHJ. More importantly it is now accepted that the poor functional status of a replaced fractured proximal humerus is directly related to migration, malunion and/or resorption of the tuberosities. Despite the evolution of design in shoulder prosthesis and the repair of the tuberosities this complication continues to date. Survivorship of the prosthesis does not appear to be a problem with a 94% survival rate at 10 years.

Complications of PHF are related to the injury and the treatment. In addition to immediate fracture related complications such as neurovascular compromise soft tissue disruption commonly experienced complications are listed in Box 12.36.4.

Post-traumatic stiffness is the most common complication of PHF as the shoulder girdle function is heavily dependent on the surrounding soft tissues in order to maintain a wide range of motion with efficiency. Injury severity and prolonged immobilization in internal rotation may result in recalcitrant stiffness and poor functional outcome. Fixed internal rotation or the lack of external rotation is probably the most disabling deformity. It cannot be overemphasized that the fracture pattern or final construct following intervention must allow early movement and in particular external rotation of the GHJ.

Most PHF will eventually heal with a degree of malunion. In the immature skeleton up to 45 degrees of angulation will remodel successfully. The true incidence of symptomatic malunion is unknown as it is poorly defined as to what constitutes malunion in PHF. In a retrospective review, of patients that underwent surgery for malunion, three types were identified (Table 12.36.3). They reported 69% successful reconstruction and 31% complication rate associated with poor outcome. In 79% of the patients there were associated soft tissue abnormalities with 80% being capsular contractures.

The functional disability often is the result of additional global stiffness rather than structural alone. It appears that tuberosity malunion is the most responsive to treatment either with osteotomy or with acromioplasty, whilst replacement with prosthesis appears less successful and is associated with more technical problems as compared with primary hemiarthroplasty for acute fractures.

Non-union of the PHF is underreported. This may reflect the population characteristics and the practice of short follow-up without radiology. It is, not unreasonably, assumed that the clinical picture does not correlate with the imaging. Neer has described a distinct pattern of non-union and pseudarthrosis often seen in fractures of the surgical neck. Widely displaced two-part fractures of the proximal humerus are reported to have a 4.7% incidence of non-union. Mobile non-unions are symptomatic as patients often complain of painful clicking and lack of strength in the arm: they are unable to lift themselves off the chair or use their walking aid (Figure 12.36.7). This is a therapeutic challenge as reduction and fixation is challenged by poor bone stock. Hemiarthroplasty for non-union is technically demanding and often results in exchange of a flail arm with stiffness.

AVN is associated with fractures through the anatomical neck and historically with reduction and fixation of four-part fractures. It was initially thought that all four part fractures carried a significant risk of AVN; however the position changed once realized that in valgus displaced fractures the vascular supply of the head fragment is preserved and the outcome is favourable. Appreciation of the vascular pattern of the humeral head and improved operative skills has led to a significant decrease of AVN following surgery. Recent report on the operative treatment of high-energy fractures suggested that the incidence of AVN is 35% with 20.6% partial (Figure 12.36.8) and 14.7% total. As expected patients with AVN did worse as assessed with outcome scoring tools.

Although stiffness in many circumstances is unavoidable, it is essential to commence physical therapy as soon as the fracture pattern or construct will allow. Results following early and late physiotherapy treatment show a significant difference in the outcomes at 1 year. The Neer regimen of four 3-weekly periods of passive range to resistance exercises with individual modifications to allow for patient characteristics seems to be universally accepted. Measurable improvement continues for approximately 6 months following injury, thereafter, functional improvement is most likely due to compensatory mechanisms and activity modification.

As with all injuries, fractures of the clavicle it is a spectrum of injury with the majority of fractures resulting in an uncomplicated recovery and return to the pre-injury functional status.

The clavicle is an ‘S’ shaped bone with no medullary canal. The ossification starts in the 5th week of gestation, whilst the medial physis ossifies at the age of 25 years. It is the strut connection of the arm to the trunk via the sternoclavicular, acromioclavicular joints and the coracoclavicular ligaments and multiple muscle attachments. It is suspended like a crane via the trapezius, sternocleidomastoid and subclavius muscles and moves 30 degrees in the coronal plane, 35 degrees on the sagittal plane, and rotates 50 degrees to facilitate the version of the glenoid during GHJ movement clearing the arm of the trunk.

Fractures of the clavicle represent 10–12% of all fractures. The prevalence in the adult population is 30–64/100 000/year. It affects all ages with a peak in the young males during sporting activities. Motor-vehicle collision is the second most common mechanism of injury in males whilst the male to female ratio evens with advanced age. Direct impact is in most circumstances the mechanism of injury. Open fractures occur in 1.4% of the fractures treated in a level I trauma centre in the United States of America and are associated with head and torso injuries.

Altman in 1967 classified the fractures in medial, middle, and lateral thirds. Robinson identified subgroups within Altman’s classification after collecting large number of data (Table 12.36.4).

The clinical diagnosis is obvious in most fractures. Standard radiographs will include an anteroposterior and a 20-degree tilted view as displacement cannot be assessed on single view alone. In high-energy injuries associated girdle injuries or chest trauma may be present and these injuries may require immediate attention. This is especially true in the presence of open clavicle fractures. Widely distracted fractures of the clavicle should raise the suspicion of scapulothoracic dissociation, especially if accompanied by neurovascular compromise. In association with fractures of the scapula the disruption of the superior shoulder suspensory complex (SSSC) may lead to unacceptable displacement.

Eighty-nine per cent of all clavicle fractures go on to uneventful union with symptomatic treatment alone. Open fractures or fractures associated with vascular compromise are absolute indications for operative treatment in line with the general principles of orthopaedic trauma.

Reduction of the displaced fractures of the middle third was recommended using a figure-of-eight strapping. However, the reported results comparing simple sling and the figure-of-eight strapping did not show a difference in the final outcome. The figure-of-eight treatment has been abandoned in United Kingdom practice as it is associated with complications and does not affect outcome in terms of fracture healing.

The dogma that all clavicle fractures unite uneventfully has been challenged in the past with sporadic reports on case series of non-unions. Increasing number of reports identified subgroups of fracture patterns such as severe shortening and fragmentation to be associated with delayed/non-union. Furthermore, there has been some concern that malunion of the clavicle is associated with pressure phenomena and poor functional outcomes. Recent randomized studies suggest that certain fracture patterns may benefit from early intervention in terms of time to union. However the operative treatment was not without complications that were reported to be 37%.

Fractures of the lateral third of the clavicle are another subgroup that has attracted interest as the incidence of non-union is approaching 30% especially for the displaced Neer II/Robinson 3B type of fractures: it is accepted that these non-unions are mostly asymptomatic. In a 15-year follow-up, 95% of non-unions were asymptomatic. In a separate study only 14% of the non-unions required further surgery (Figure 12.36.9).

Operative repair of distal clavicle fractures is not without technical difficulties and complications mainly due to the inheritably unstable pattern of injury, poor bone purchase, and need of the fixation crossing mobile areas around the shoulder. The variety of techniques illustrates the difficulty of the problem (Figure 12.36.10).

Box 12.36.7 lists the current thinking regarding indications for operative treatment of clavicle fractures.

The acromioclavicular joint (ACJ) is a diarthroldial joint with a meniscus and a strong capsule which in conjunction with the coracoclavicular ligaments suspends the scapula from the clavicle. The kinematics of the joint have been studied and a 20-degree arc of tilting, rotation and protraction has been identified.

ACJ joint injuries are common in males as the result of sporting injuries with direct force on the shoulder. They represent 12% of the shoulder injuries and in their majority these are simple sprains.

The classification in Box 12.36.8 suggested by Tossy 1963 complemented by Rockwood appears to be universally accepted.

The mechanism of injury and corresponding clinical signs are pathognomonic of the injury. Radiographs exclude the presence of a fracture of the distal clavicle. Weight bearing comparative views are occasionally necessary to differentiate a type 2 from a type 3 injury.

Universal agreement exists for type 1 and type 2 injuries: these are treated symptomatically (Box 12.36.9). Pain usually resolves within 3 weeks and function returns with simple physiotherapy exercises.

Whilst there is some debate regarding type 3 injuries, current evidence would support non-operative treatment. Patients are not easily convinced that the symptoms will soon settle and that the shoulder function will return despite the residual deformity. Follow-up consultation in 2–3 weeks allows more insight to the effects of the injury.

Evolving minimally invasive techniques in the acute setting has resulted in increased interest in early intervention as scarring in the region of the coracoclavicular ligaments may abolish the need for ligament transfer and reconstruction (Figure 12.36.12).

Symptomatic patients will respond to reconstructive surgery of distal clavicle excision, ligament reconstruction and augmentation. The Weaver–Dunn procedure with its many modifications remains the template for stabilization of the distal clavicle. Symptoms often relate to cosmesis, lack of strength, and/or painful clicking of the joint in order of frequency.

Early operative treatment is required for the more rare and severe disruptions that will impinge on shoulder movement such as the locked and widely displaced (Rockwood types IV and V) and subcoracoid (Rockwood VI) injuries.

Numerous publications refer to the results of primary operative versus non-operative treatment and later reconstruction. The current practice varies depending the surgeon’s experience and interpretation of the reported literature. It is reasonable to accept that the majority of these patients would do well either with or without operative treatment. With the exception of cosmesis, as a consistent indication for surgery, it is not obvious at presentation which subgroup of patients would benefit from early intervention.

The sternoclavicular (SC) joint is a saddle joint connecting the clavicle to the axial skeleton. It has a range of motion of 35 degrees in the coronal plane and 70 degrees in the anteroposterior plane. For all practical purposes the articulation functions as a ball and socket joint. Stability relies partially in skeletal anatomy and more so in the strong and complex ligamentous structures (costoclavicular, interclavicular, anterosuperior, and posterior capsular reinforcement) and the subclavius muscle. The medial end of the clavicle physis ossifies by the age of 25, hence injuries to the region in young adults represent physeal fractures.

The mechanism of injury can be direct or indirect. As a result it can occur in a variety of injuries such as sport and motor vehicle accidents. The posterior dislocation may be associated with a dramatic clinical picture of airway obstruction whilst the sporting injuries can be easily overlooked.

The overall incidence of the injury to SC joint is reported as 1% of all dislocations and 3% of the dislocations of the upper limb. As with all injuries there is a spectrum of injury (Box 12.36.10).

Whilst the history of injury and clinical symptoms are significant often the deformity is mild (especially with posterior injuries) and the plain radiographs difficult to interpret. Special views and measurements have been recommended but CT is the investigation of choice (Figure 12.36.13).

Immediate reduction of a posteriorly displaced medial clavicle is part of the ATLS protocol for emergency treatment of airway compromise. In the less acute setting the treatment options vary according to the injury, the individual and the timing of the diagnosis (Table 12.36.5).

There are few relatively small case series in the literature reporting the results of operative techniques. Whilst there in no conclusive evidence regarding the treatment methods, it appears that open reduction with autologous tendon reconstruction without transfixation is associated with the best results (Figure 12.36.14) whilst medial clavicle excision and joint transfixion are associated with poorest results and highest incidence of complications respectively.

Complications relating to SCJ injuries are listed in Box 12.36.11.

The scapula is a mobile platform suspended form the axial skeleton by the clavicular ligaments, the ACJ capsule and a variety of muscles. It provides the fulcrum (glenoid) for the arm movements and rotates to facilitate universal arm movement (scapulothoracic articulation) and is the site of origin for 17 muscles. Fractures of the scapula account for 1% of all fractures, 3–5% of fractures of the shoulder girdle, and occur in 3% of patients with multiple injuries.

Fractures of the scapula are subdivided according to anatomical topography. As considerable force is required for scapular fractures to occur, concomitant injuries are associated with particular fracture types (Table 12.36.6).

Despite the history of significant trauma scapula fractures are missed at presentation in 43%. Likely reasons are the incidence of associated injuries (85–90%) mainly of the ipsilateral shoulder girdle or to the thorax and poor visualization on plain radiographs. It is expected that with the liberal use of CT to assess thoracic trauma the pick-up rate of scapula fractures will increase.

The incidence of associated neurological and vascular complications is reported to be 5–12%.

Glenoid fractures account for 10–15% of the scapula fractures. Approximately 10% are significantly displaced to pose a treatment dilemma. Hence the absolute incidence of displaced glenoid fractures to be considered for intervention is 1:10 000 fractures. Glenoid fractures are classified according to Ideberg based on the force vector of the humeral head on the glenoid fossa (Table 12.36.7).

Principles of treatment of articular fractures in terms of joint stability and congruence are valid and reproducible; however the true incidence of degenerative changes due to intra-articular malunion is unknown.

Glenoid neck fractures in association with a clavicle fracture were described as ‘the floating shoulder’. The injury was considered highly unstable and thought to be associated with poor outcome. However, recent experience has questioned the dogma of instability of floating shoulders and clarified the indications regarding the need for intervention. Current thinking relates to the medial and caudal displacement of the glenoid fragment. It considered that caudal tilt greater than 40 degrees and medial displacement more than 1cm may affect GHJ motion and represent indication for operative intervention.

Fractures of the scapula body including the spine are the most common fractures of the scapula. In the absence of articular involvement the fractures are treated symptomatically with particular care to the associated chest injuries. Fractures that involve the supraclavicular notch may be associated with suprascapular nerve damage that in the context of loss of function due to pain may be difficult to diagnose early.

Fractures of the acromion are extremely rare as it is more likely that a direct force would result in injuries to the neighbouring anatomical structures mainly the acromioclavicular joint. Concerns and dilemmas with malunion and or symptomatic non-union are raised with significant displacement. Os acromiale may pose a diagnostic pitfall.

Coracoid fractures compromise 2–5% of scapula fractures and have been related to a variety of mechanisms of injury. Fractures of the base are more common; despite the rarity of the injury six types have been recognized and operative treatment recommended for injuries associated with AC disruption.

Scapulothoracic dissociation (SCTD) is a potentially life-threatening injury depicting a closed forequarter amputation with neural and vascular damage and essential disarticulation of the scapulothoracic joint. Since the original description in 1984 variations of the injury have been described and the spectrum of injury further classified (Table 12.36.8). Whilst immediate management relies on timely revascularization of the limb it appears that the long term outcome of injury heavily relies on the presence and extent of brachial plexus injury.

Attention should initially address life and/or limb-threatening conditions.

Specific treatment for scapula fractures is based on small retrospective case series and knowledge boosts from their meta-analyses. Most scapula fractures are treated symptomatically. It has been estimated that, using current indications, an orthopaedic surgeon would operatively treat 1.5 fractures of the scapula during his/her career.

A recent meta-analysis of the literature identified 243 patients from 17 publications that had operative treatment for scapula fractures. Most of the fractures involved the glenoid (48%) and 20% involved the glenoid neck. Using a variety of scoring systems results were rated excellent and good in 84% and fair and poor in 16%. Operative treatment complications were infection 4.2% and nerve damage (suprascapular) 2.4%.