Brachial plexus birth palsy

Injuries to the brachial plexus that occur during birth are referred to using several different terms in the literature, including “brachial plexus birth palsies” (BPBPs) and obstetric, neonatal, or pediatric brachial plexus palsy. BPBP generally results from a traction or stretching injury to the shoulder during a difficult vaginal delivery. Along with clinical entities such as hip dysplasia, cerebral palsy, clubfoot, and polydactyly, these represent among the more common newborn consultations for pediatric orthopedic caregivers. Although cases of BPBP have also been reported during C-sections, this scenario is considered extremely rare. The reported incidence of the condition is between 1 and 4 cases per 1000 live births. Risk factors for BPBP include multiparous pregnancy, prior pregnancy with BPBP, fetal macrosomia, breech position, prolonged delivery, assisted delivery with vacuum or forceps, and shoulder dystocia. Many affected neonates eventually spontaneously recover normal or near-normal upper extremity function, but close monitoring and expertise in treatment are critical to optimizing the outcomes of those patients whose motor recovery is incomplete.

Detection or “presentation” of the condition is generally in the immediate neonatal period when parents or health care providers observe deficits or absence of motor function of the hand or arm. The right upper extremity is more commonly affected due to the left occipital anterior vertex presentation at the time of birth. Breech presentation has an association with C5 to C6 root avulsions and may be bilateral. Physical exam signs depend on the severity and level of nerve root involvement. C5 involvement will affect the axillary nerve, leading to deltoid and teres minor weakness; the suprascapular nerve, leading to supraspinatus and infraspinatus weakness; and the musculocutaneous nerve, leading to biceps and brachialis weakness. C6 involvement affects the radial nerve, leading to brachioradialis and supinator weakness. The classic physical exam finding associated with a C5 to C6 neuropraxia, or an “upper lesion” or “upper trunk lesion,” is seen when the child’s arm is held in an adducted, internally rotated posture due lack of shoulder abduction and external rotation (ER) motor function. When C7 is also involved, wrist and finger flexion is preserved, but the paralysis of deltoid, biceps, and wrist/finger extension creates a “waiter’s tip” appearance, with the wrist and fingers flexed and facing laterally or posteriorly. Although seen in adult injuries, the isolated C8 and T1 injury is rarely seen in birth injuries and signifies a “lower lesion,” “lower trunk lesion,” or Klumpke palsy, characterized by ulnar and median nerve deficits, among others. In this scenario, weakness of the intrinsic muscles of the hand and wrist flexors leads to wrist hyperextension, metacarpophalangeal hyperextension, and flexion of the interphalangeal joints, collectively creating a “claw hand” appearance. When both upper and lower nerve roots have been affected, a total plexus palsy (C5 to T1) will present as a flaccid upper extremity throughout. These more severe injuries are less likely to recover by natural history alone.

In addition to which nerve roots are affected, the mechanical injury sustained and precise location along the nerve root’s course are also critical, with neuropraxia (Sunderland I lesions) representing an intact but stretched nerve root, whereas axonotmesis (intact root, intraneural fascicle rupture, Sunderland II to IV), neurotmesis (postganglionic tear with extraforaminal root or trunk rupture, Sunderland V), or preganglionic avulsion of the root from the spinal cord represents increasingly severe injuries.

The associated motor palsies themselves are generally painless, such that any suggestion of pain with passive upper extremity motion warrants radiographic workup of a clavicle or humerus fracture, although these fractures can occur in conjunction with BPBP. Assessment of the Moro reflex, in which an infant will reflexively abduct both arms in response to sudden loss of support or lowering of the head relative to the trunk, is an important test for BPBP. Upper extremity motor deficits will also cause an abnormal asymmetric tonic neck reflex, which is the normal phenomenon, up to 6 months of age, of abduction of the arm on the side to which an infant’s head is turned, with reflexive elbow flexion on the contralateral side. (This is also referred to as “the fencing reflex” due to the positional resemblance to that of a fencer.) Although other causes of altered Moro reflex or asymmetric tonic neck reflex exist, BPBP becomes an important diagnosis of exclusion when these are detected as abnormal.

The most frequently used BPBP classification system used for infants in the first month of life is the Narakas classification, in which the most commonly occurring group I subset (46%) denotes injury to nerve roots C5 and C6 (Dhuchenne-Erb palsy, or simply Erb palsy), leading to paralysis of the deltoid, rotator cuff, and biceps, but with intact wrist and finger flexion and extension. Group II BPBP (29%) encapsulates cases with injury to nerve roots C5 to C7, with loss of deltoid, rotator cuff, biceps, and wrist/finger extension, but wrist and finger flexion is preserved. Those infants with Narakas II with early wrist extension recovery do better by natural history than those without early wrist extension recovery. Groups III and IV are both “total BPBPs,” characterized by a flail extremity, with group IV having the distinction of Horner syndrome (defined as the trio of ptosis, miosis, anhydrosis) in group IV. Group IV patients may also have a phrenic nerve palsy with a paralyzed, elevated hemidiaphragm, which represents a poorer prognosis. Although classification of nerve injury is a critical step following neonatal diagnosis, continued assessment of global upper extremity function during the first 3 to 9 months of life for decision making on nerve surgery and into childhood for decision making regarding shoulder reconstruction is an integral feature of management of BPBP. Several classification systems have arisen to characterize such functional levels, with different advocates of each over time. An important study compared the reliability of the modified Mallet classification, the Toronto Test Score, and the Hospital for Sick Children Active Movement Scale in 80 affected children, demonstrating reliability for all three instruments.

Conditions that are associated with BPBP include neonatal clavicle and humerus fractures, which are also common birth injuries with similar risk factors, as well as infantile torticollis, progressive glenohumeral dysplasia, and flexion contracture of the elbow. The glenohumeral dysplasia associated with BPBP develops over time and is characterized by a spectrum of severity of glenoid retroversion, humeral head deformity/flattening, and posterior glenohumeral instability, with unopposed shoulder internal rotation and evolving contracture playing the principal etiologic role. Waters et al. described a classification system in 1998 of seven different subtypes of glenohumeral dysplasia, which remains in widespread use among experts nowadays and, along with nerve recovery, becomes a critical indicator of overall upper extremity function and global prognosis. As an infant with BPBP ages in childhood, close monitoring is therefore important to assess glenohumeral ER passively, performed with strict stabilization of the scapula to eliminate scapulothoracic motion, as Kozin has shown a direct correlation of decreasing ER values correlating with worsening glenohumeral pathoanatomy. As a measure of the unchecked natural history of BPBP over time, Waters et al. used computed tomography (CT) and magnetic resonance imaging (MRI) to characterize a mean glenoid retroversion of 25.7 degrees in BPBP patients (compared with 5.5 degrees on the unaffected side). Importantly, this value became greater with increasing age. Hoeksma et al. demonstrated that when children were followed to a mean age of 3.7 years, the rates of shoulder contractures greater than 10 degrees were more than 50%, even in children who achieved complete neurologic recovery, and osseous deformity of either the glenoid or humerus arose in one-third of BPBP patients.

When considering the natural history of BPBP, group I has the best prognosis, with work by Waters in 1999 supporting previous studies by Wyeth and Sharpe and Gilbert and Tassin, that return of biceps function around 3 to 4 months represented a critical predictor of long-term function. A preganglionic root avulsion has the poorest prognosis and may generally be predicted by the presence of a Horner syndrome, a phrenic nerve palsy (elevated hemidiaphragm), or absence of function of one or more muscle groups whose innervating structures arise close to the ganglion, such as the dorsal scapular nerve (rhomboids), thoracodorsal nerve (latissimus dorsi), suprascapular (supraspinatus/infraspinatus), or serratus anterior/winged scapula (long thoracic nerve). Because of this critical differentiation between preganglionic and postganglionic injury, significant study into different diagnostic modalities—including myelography, CT myelography, MRI, magnetic resonance myelography, magnetic resonance neurography, electromyography, and nerve conduction studies—to elucidate injury localization has not yielded clear support for any particular modality, such that most experts consider meticulous physical examinations over time to be the most important diagnostic element. Therefore, although MRI is extremely helpful for assessing the status of the glenohumeral joint in children later in the natural history of BPBP, advanced imaging is not considered an integral component of early assessment of actual nerve injury.

Treatment of the most common group I injuries begins with observation over time for spontaneous nerve recovery, particularly antigravity biceps function, with 3 to 6 months being the critical prognostic endpoint of potential return. Antigravity upper trunk motor recovery in the first 2 months generally predicts complete recovery within 1 to 2 years of age. Within the early months after diagnosis, it is recommended that parents, with the help of guided physical therapy, perform daily passive shoulder, elbow, wrist, and finger range-of-motion (ROM) exercises, to avoid joint contractures. Milder elbow flexion contractures less than 40 degrees may be treated with serial elbow extension splints at night, with more severe contractures greater than 40 degrees undergoing serial extension casting.

Surgical interventions for the primary BPBP injury consist of neuroma resection/transection and nerve grafting, nerve transfer, and neurotization, all of which depend on severity and nerve root involvement. For postganglionic BPBP, in which the nerves are injured but the nerve roots remain attached, microsurgical nerve grafting with the sural nerve has good outcomes when used. These have been more commonly pursued for Narakas groups I and II injuries that do not demonstrate spontaneous recovery by 3 to 6 months of age and range from Sunderland II to IV injuries. However, the timing of such interventions remains the subject of significant controversy, with Gilbert and other authors ^, advocating for surgery by 3 months, whereas Waters and Al-Qattan have shown waiting to assess recovery of biceps function by 4 to 5 months may lead to outcomes comparable with those achieved with earlier microsurgery, particularly when tendon transfers and shoulder-related deformity are addressed at the later time point. The sural nerve grafting procedures are performed from the C5 and C6 roots to most proximal healthy portions of the upper trunk (both lateral and posterior cord) and suprascapular nerve. There are also nerve transfer options, including partial ulnar to biceps motor branch, partial radial to axillary motor, and partial spinal accessory to suprascapular nerve.

For preganglionic nerve root avulsions with gross detachment of the roots, nerve transfer or neurotization is pursued, with little controversy regarding the benefit of such interventions before 3 months of age, given the known lack of expectable recovery and ability to limit motor endplate loss before this age. Unfortunately, there may be few nerve grafting options, especially for C7, C8, and T1. Nerve transfers involve moving fascicles from a working nerve to another nerve that is demonstrating deficits, whereas neurotization involves the fascicles being transferred to a neuromuscular junction rather than a nerve itself. Although these are more common with lower plexus lesions, one exception has been upper trunk lesions associated with breech presentation, in which preganglionic C5 to C6 avulsions may be seen. Commonly transferred nerves include the thoracic intercostals (T2 to T4) and the spinal accessory nerve (CN IX, taken beyond the innervation of the trapezius). For total plexus avulsions, in addition to these two nerves, the phrenic, cervical plexus, contralateral C7, and hypoglossal nerve have all been used with limited success.

When shoulder internal rotation contractures persist in children up to the first 1 to 2 years of age, as is true for the majority of patients who do not demonstrate antigravity biceps function return within the first 2 months, future surgical intervention is often warranted. Newer studies suggest that interventions before 2 years have superior results to those delayed beyond 2 years. Interestingly, Waters et al. analyzed MRI in 74 patients with different degrees of glenohumeral deformity, showing the degree of deformity correlated with the ratio of internally to externally rotating musculature, as measured on axial imaging. Some early studies suggested simple open reduction and anterior tendon lengthening may be effective in reducing glenoid retroversion over time. However, the Hoffer procedure, first described in 1978, gained popularity with its addition of tendon transfers. In this technique, the latissimus dorsi and teres major insertions are transferred from an anteromedial position on the proximal humerus to a posterolateral position to generate more ER forces. The pectoralis major and subscapularis, which are frequently shortened over time in conjunction with BPBP, are usually lengthened in conjunction, and anterior glenohumeral capsular contractures may be released. Importantly, overrelease of the subscapularis and/or anterior capsule may result in an ER posture, which limits internal rotation function to midline later. Historically performed with an open anterior approach, Pearl first described the anterior capsular release as an arthroscopic technique in 2003, and others have shown success with this approach, with Kozin et al. recommending partial release of the superior tendinous portion of the subscapularis but preservation of the inferior and lateral muscular portions to lessen risk of internal rotation weakness and ER contracture postoperatively. Open reduction can be performed at the same time as latissimus dorsi and teres major tendon transfers for ER function, with partial musculotendinous lengthening of the pectoralis major and subscapularis to allow for centering of the humeral head in the glenoid. If performed early, the combination of lengthening, transfers, and joint reduction can lead to glenoid remodeling in the majority of patients. ^, Ezaki et al. proposed the use of botulinum toxin-A injection into the internal rotator muscles as a useful adjunct to the treatment of early posterior subluxation or dislocation of the shoulder in select patients. The authors demonstrated successful shoulder reduction in 69% of 35 patients who either underwent one ( n = 29) or two ( n = 6) injections at approximately 6 months of age. First gaining interest in the late 1990s and early 2000s but with outcomes most convincingly substantiated in 2006 by Waters and Bae, derotational osteotomy of the proximal humerus also improves global upper extremity function and may be particularly suited for older children with more advanced glenohumeral dysplasia, in whom soft tissue releases and tendon transfers may be more difficult. The addition of slight varus alignment to the osteotomy was also shown to be beneficial in patients with both internal rotation and abduction contractures resulting from transfers without joint reduction remodeling. More distal secondary interventions are designed to address persistent contractures, such as elbow flexion contracture with capsular release and biceps or brachialis tendon lengthening, or a biceps tendon transfer for persistent supination contracture. Therefore, although the precise treatment approach should be individualized to some degree, in each child’s case, the evidence-based approach most commonly favored at Boston Children’s Hospital, based on the available literature, tends to be sural nerve grafting for postganglionic BPBP in which biceps recovery is not detected by 4 to 5 months of age, with the addition of subscapularis and pectoralis major tendon lengthening, latissimus dorsi and teres major tendon transfer, and, when appropriate, derotational osteotomy, for glenohumeral deformity between 6 and 24 months of age.

Overall, complications associated with BPBP-related surgeries are relatively rare but may include infection, bleeding, and worsening neural status. For example, phrenic nerve palsy may recur and can be treated with late diaphragmatic plication. Incomplete neural recovery reflects the more accurate natural history following surgery more than a true complication and should therefore be fundamental to the preoperative and perioperative discussions with parents and family members.

Sprengel’s deformity

Named after Otta Gerhard Karl Sprengel, the German surgeon who provided the first detailed or definitive description of four cases in 1891, Sprengel’s deformity is the most common congenital anomaly of the shoulder and is characterized by scapular hypoplasia, the appearance of scapular “winging,” and, in 30% to 50% of cases, an omovertebral connection from the superomedial scapular border to the cervical spine. More than true winging, as it is classically described, the deformity rather represents a failure of the scapula, during weeks 9 to 12 of fetal development, to descend inferiorly along the chest wall into its normal, coronally oriented position along the second through seventh ribs. Despite not all cases having winging, serratus anterior muscle weakness may be present in Sprengel’s deformity so as to cause true winging. Although frequently referred to as demonstrating an “elevated” scapula, Sprengel’s deformity is more accurately a dysmorphic scapula that has experienced a failure of descent, which leads to a smaller, more sagittally inclined and more protracted scapula. The trapezius, levator scapulae, and rhomboids are frequently hypoplastic or relatively weak as well. Ultimately, these collective features result in the inferomedial scapular angle and glenoid to be tilted inferiorly, which limits scapulothoracic motion, overall shoulder abduction, and global shoulder function.

As a relatively rare condition, there is little literature elucidating its origins or incidence in terms of methodologically rigorous or definitive epidemiologic or etiologic data. The omovertebral connection or synchondrosis, of sorts, between the superomedial angle and cervical vertebrae may be fibrous, cartilaginous, bony, or some combination thereof. However, it has been reported to be bilateral in 10% to 30% of cases and may have an autosomal dominant inheritance pattern in a subset of affected patients. Moreover, an association has been established between Klippel-Feil syndrome and Sprengel’s deformity, which may be found in up to one-third of patients with Klippel Feil, which is characterized by abnormal cervical vertebral fusion, a shortened-appearing neck, and a low hairline. Other entities that have been associated with Sprengel’s deformity include congenital rib abnormalities, thoracic insufficiency, torticollis, and scoliosis.

The most commonly used classification system was proposed by Cavendish in 1972, in which a grade 1 deformity denotes subtle radiologically detectable features that are not clearly visible on simple inspection; grade 2 deformity is seen only as an asymmetric neck prominence but without clear shoulder deformity; grade 3 deformity is easily visible, with up to 2 to 5 cm of asymmetry in shoulder elevation; and grade 4 deformity has greater than 5 cm, with or without neck “webbing.” Several years after the emergence of this classification system, which revolved around physical exam findings, Rigault et al. proposed a radiographic system based on the resting height of the superomedial angle of the scapula, with a more “undescended” scapular position described by a more severe grade: between T2 and T4 (grade 1), between C5 and the T2 transverse process (grade 2), or above the T2 transverse process (grade 3).

Because of its relative rarity, the natural history of Sprengel’s deformity, particularly within different grade-based subpopulations, has not been well described. One study was limited to 14 patients with either Cavendish grade 1, 2, or 3 presentations having been treated nonoperatively and followed into adulthood (up to age 67 years old). Approximately half of this cohort was found to have mild to moderate pain with activity and ROM restrictions, suggesting suboptimal outcomes in many with simple observation.

Although the classification systems offer some guidance when considering surgical indications, procedures may be considered on a somewhat individualized basis and are generally reserved for symptomatic children 1 to 3 years of age or older who have significant functional, rather than simply cosmetic, limitations or complaints. For example, although superomedial scapular angle resection represents a reasonable surgical option to address the cosmetic aspects of the deformity, ^, studies have not supported its ability to significantly improve shoulder function. Similarly, the vertical scapular osteotomy first described by Konig improved the appearance of the laterally elevated portion of the scapula but did not result in improved glenoid position or shoulder function. ^, Therefore the superomedial angle resection and scapular osteotomy are generally not favored over other surgical options, such as the modified Green procedure or modified Woodward procedure. In 1957, Green proposed his technique in which the muscular attachments to the scapula were elevated from the bony surface and advanced so as to move the scapula to a more inferior position. Several years later, in 1961, Woodward described a different technique with similar principles, and this has emerged as the best-studied technique to date.

Performed with the patient in the prone position, the Woodward procedure involves elevation of the entire muscular sleeve of medial rhomboids and trapezius from the vertebral column, taking care to preserve the periosteum on the bony surface of the spine and reflecting the musculotendinous layer laterally. The underlying omovertebral connection is resected, as is the superiomedial border of the scapula in most cases, after elevation of the levator scapulae and supraspinatus from their scapular attachments. Repositioning of the scapula in a distalized, lateralized position using the scapular spine to achieve symmetry with the normal contralateral scapula may not be possible due to subfascial attachments to the underlying chest wall. Release of such adhesions should provide the necessary mobility to optimize scapular position, after which reattachments of the levator scapulae and supraspinatus to the new superomedial scapular angle (postresection), and the rhomboids and trapezius to a more distal position on the spinous processes, should maintain such position.

Among the complications described following the Green and Woodward procedures, which may include wound infection, hematoma formation, and cosmetic concerns related to the large incisional scar, the most significant is brachial plexus palsy. Several authors have reported this phenomenon, which stems from compression of the clavicle, which becomes posteriorized during scapular distalization, and the first rib. ^{, ,} Therefore some authors have proposed the addition of a clavicular osteotomy, performed immediately prior to the Woodward procedure in the supine position, particularly in cases of more severe deformity or older patient age. This requires simple removal and morselization of a 1-cm section of mid-diaphyseal clavicle, performed within a meticulously dissected clavicular periosteal sleeve, which is then sutured over the morselized graft, prior to rolling the patient prone for the scapular procedure. While eventually undergoing robust bony healing, in the critical, early postoperative period, the resulting osteotomized clavicle does not compress the clavicle to the anterior chest wall to dangerous levels. This has therefore been an important adjunctive technique for avoiding brachioplexopathy in select patients.

Reported outcomes by multiple authors on the modified Woodward technique have suggested improvement in shoulder abduction approximating 40 degrees and 1- to 2-category improvement in the Cavendish grade, to go along with cosmetic improvements. ^{, ,} In a smaller number of level four studies with smaller sample size, similar cosmetic and functional improvements have been reported by enthusiasts of the modified Green procedure.

Fractures of the proximal humerus

Mechanism of injury

Shoulder dystocia is an infrequent cause of birth injuries and is associated with maternal diabetes, macrosomia, post-term pregnancy, and a previous history of shoulder dystocia. Gherman and colleagues reported the incidence of birth injuries associated with shoulder dystocia to be 24.9%, with a 4.2% incidence of proximal humeral fractures. The mechanism of injury is related to arm position during delivery. Hyperextension and ER of the shoulder have been implicated in birth fractures, including separation of the proximal humeral physis.

Fractures of the proximal humerus in older children and adolescents are more frequently caused by direct and indirect trauma to the shoulder and proximal humerus. Sports injuries, vehicular trauma, and falls are the most common cause of proximal humerus fractures in children. Given the explosion of youth sports participation in the past one to two decades and the well-documented increases in youth sports injuries, sports-related causes of proximal humerus fractures will likely continue to rise as an etiologic factor relative to these other causes.

Repetitive injury can also cause damage to the proximal humeral physis ( Fig. 6.1 ). Shoulder pain and proximal humeral epiphysiolysis, commonly referred to as “little league shoulder,” has been reported in baseball pitchers and other overhead athletes due to excessive repeated traction and torsional loads at the proximal humeral physis. The largest report to date on the subject described a series of 95 patients (mean age 13.1 years) with little league shoulder who were successfully treated with 3 months of rest from throwing, although recurrence was seen in 7% of patients. Importantly, 30% of affected patients were found to have glenohumeral internal rotation deficit syndrome, a finding that was 3.6 times more likely in patients who developed recurrence, speaking to the importance of underlying modifiable risk factors that require awareness and attention in the early treatment phase.

Anteroposterior external rotation radiographs of bilateral shoulders in a 13-year-old skeletally immature right hand–dominant baseball pitcher demonstrates lateral physeal “widening” (arrow) , or periphyseal lucency, on the right proximal humeral physis, compared with a normal-appearing left proximal humeral physis, which confirmed the diagnosis of little league shoulder.

(Courtesy Benton E. Heyworth, MD, Boston Children’s Hospital; copyright COSF.)

Pathologic fractures occurring through benign lesions have been reported infrequently ( Fig. 6.2 ) but are most commonly caused by aneurysmal and unicameral bone cysts. Malignant lesions have been reported to cause pathologic fractures through the proximal humerus and, although infrequently seen, should be considered in the appropriate clinical setting.

(A) A 7-year-old boy sustained a pathologic fracture through a unicameral bone cyst. This fracture was treated conservatively with a shoulder immobilizer. (B) Follow-up radiographs show healing of the pathologic fracture, with the presence of a residual cystic lesion. (C) The residual cystic lesion was treated with percutaneous biopsy, curettage, and bone grafting with calcium sulfate pellets. (D) The latest follow-up films show progressive healing and remodeling through the lesion without evidence of physeal injury or growth disturbance.

Metabolic conditions, such as pituitary gigantism, can cause weakening of the growth plate, leading to the development of deformity. Underlying neuromuscular conditions, such as Arnold-Chiari malformation, syringomyelia, myelomeningocele, and cerebral palsy, have been identified as risk factors or etiologic agents in the development of growth plate injuries and fractures about the proximal humerus.

Nonaccidental injury should also be considered when children present with a proximal humerus fracture, particularly if the underlying cause is unclear and multiple injuries are noted.

Classification

Fractures of the proximal humerus in children can be classified according to the location of the injury. Growth plate injuries in children are classified according to the Salter-Harris classification. In children younger than 5 years of age, Salter-Harris type I injuries predominate ( Fig. 6.3 ), whereas, in children older than 11 years, type II fracture patterns predominate ( Fig. 6.4 ). Salter-Harris types III, IV, and V are very rare, particularly in the proximal humerus, although cases of Salter-Harris type III injuries have been reported.

Anteroposterior radiograph of a 2-year-old who sustained a displaced Salter-Harris type I fracture through the proximal humeral growth plate.

Radiographs of an 8-year-old who sustained a Salter-Harris type II growth plate injury as a result of a fall.

The anatomic location of the fracture may also be used for classification. Dividing the fractures according to the area of involvement, such as the proximal humeral metaphysis ( Fig. 6.5 ), physis, and lesser and greater tuberosities, eases communication regarding morphology and treatment of the fracture. Neer and Horwitz classified proximal humeral physeal fractures into four types according to the degree of displacement :

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  Grade I fractures: less than 5 mm of displacement

  
  
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  Grade II fractures: displaced by more than 5 mm but less than one-third of the width of the humeral shaft

  
  
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  Grade III fractures: displaced by up to two-thirds of the width of the shaft

  
  
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  Grade IV fractures: displaced by more than two-thirds of the width of the shaft

(A–B) Radiographs of an 8-year-old boy who sustained a metaphyseal fracture through the proximal humerus. This fracture was treated conservatively. (C–D) Radiographs taken 7 weeks after injury show advanced healing of the fracture.

The indications for operative intervention according to any given classification system are not well established, and the degree of fracture angulation remains a commonly used metric in parallel with the Neer and Horowitz system. However, there has historically been little consensus regarding angulation measurement techniques. Burke et al. proposed a method of measurement for pediatric and adolescent proximal humeral fractures with a visible proximal humeral physis. The method, derived from the Southwick angle technique used for slipped capital femoral epiphysis and performed on a simple anteroposterior (AP) view, was found to have high intraobserver and interobserver reliability and may find more widespread use in the future. Thus any discussion of proximal humeral fracture in preadolescents or adolescents should include a discussion of the Neer and Horowitz grade, as well as the angulation of the fracture, according to Burke’s method.

Open fractures of the proximal humerus, although exceedingly uncommon, can occur and are frequently classified using the Gustilo-Anderson classification for open fractures. ^,

Radiographic evaluation

Imaging of the proximal humerus can be challenging in neonates and infants because it is primarily cartilaginous. In general, in neonates and infants with a suspected fracture of the proximal humerus or proximal humeral physis, a single AP view of the chest and upper extremities may be used to screen for injuries. On these plain radiographs the relationship of the proximal humeral metaphysis, scapula, and acromion is evaluated, and these structures are compared with those on the contralateral side ( Fig. 6.6 ). An abnormal relationship of the scapula and humerus has been reported as indicating a proximal humeral physeal injury with a posteriorly displaced proximal humeral fragment, termed the vanishing epiphysis sign. ^, Ultrasound examination may also be a valuable imaging tool. Ultrasonography is quick and noninvasive, allowing the injury to be directly visualized, with the contralateral side serving as a comparison, although this technique is largely operator dependent. Arthrography can also be valuable but requires sedation. ^, Cross-sectional imaging, such as CT or MRI, has the disadvantages of ionizing radiation and need for sedation, respectively, but may be useful in evaluating shoulder injuries missed at birth, particularly those with posterior dislocation.

In a newborn, injury to the proximal humerus is usually a completely displaced physeal injury, which appears as a pseudodislocation. (A) A radiograph of a newborn can sometimes be misleading because of the absence of ossification in the proximal epiphysis. (B) Closed manipulation can be performed by applying longitudinal traction and gentle posterior pressure over the proximal end of the humerus. (C) At 2.5 weeks, abundant callus is present and the patient is clinically asymptomatic. (D) A 6-month follow-up radiograph shows symmetry when compared with the uninjured side.

Plain radiographs are still the mainstay of the initial evaluation of shoulder injuries in older children. Radiographs obtained in orthogonal views should provide adequate clinical information. A true AP image of the shoulder is taken in the scapular plane with the beam parallel to the glenohumeral joint. The axillary lateral view is preferred, although it may be difficult to obtain in a setting where a child is acutely injured. In lieu of the axillary lateral view, alternative views, such as the Velpeau axillary, West Point axillary, transthoracic axillary, or scapular Y view, may be obtained. The apical oblique and internal rotation views are also appropriate in some cases, and the ER AP projection is most valuable for assessing both acute and chronic physeal injury. ^{, ,}

Treatment

The treatment of fractures of the proximal humerus generally depends on the age of the patient, the fracture type, and the degree of displacement. In general, the prognosis for most proximal humerus fractures in children is good, with the vast majority amenable to nonoperative management. Because the proximal humeral physis contributes the most to the growth of the upper extremity and closes later in adolescence, there is tremendous remodeling potential for the proximal humerus ( Fig. 6.7 ).

(A) Radiograph of a 9-year-old boy who had sustained a Salter-Harris type II fracture of the proximal humerus, showing angulation of the proximal fragment in the anteroposterior plane. (B) The patient was treated conservatively, and a follow-up radiograph taken 6 weeks after injury shows excellent callus formation and advanced healing of the fracture. (C–D) Radiographs taken 9 months after injury show early remodeling of the proximal humerus; continued remodeling would be expected as the patient progressed toward skeletal maturity.

The prognosis is quite good in neonates with osseous birth injuries without neurologic injury. Only the most severely displaced fractures require any attempt at reduction. If reduction is performed, gentle maneuvers without formal anesthesia generally work well. Reduction may be monitored using ultrasonography. In the vast majority of cases the shoulder can be immobilized efficiently by simple swaddling of the upper extremity to the chest wall. A small ace wrap or blanket tucked thoughtfully around the newborn is favored over use of safety pins, which have a remarkable tendency to fall off or migrate. These fractures heal rapidly, usually within 2 to 3 weeks. ^,

Most preadolescents or adolescents with a mildly to moderately slipped proximal humeral epiphysis do not need any form of reduction. These injuries generally respond well to nonoperative management. Severe or complete displacement may benefit from open reduction and fixation techniques, but this is more likely in older adolescents. In general, fracture treatment is therefore determined by the degree of fracture displacement or angulation and the amount of remodeling potential. Although there are no universally accepted criteria for acceptable limits of reduction for proximal humerus fractures in children, trends in the contemporary peer-reviewed literature suggest that up to 60 degrees of angulation is acceptable in children younger than 10 to 11 years, whereas children 12 years and older should have less than 45 degrees of angulation and 50% displacement. ^, However, one should be cautious with fractures that may result in varus malunion, such as those which heal with the greater tuberosity above the level of the cartilage surface with physeal damage or in patients with limited growth remaining. These may exhibit significant limitation of passive and active motion in abduction due to subacromial impingement and reduced power from limited rotator cuff excursion, necessitating corrective osteotomy. ^,

In young children, excellent outcomes have been reported with nonoperative management. ^{, ,} In addition, older children with less angulated or displaced fractures, such as Neer and Horwitz grades I and II fractures, are frequently treated successfully without surgery, and recent evidence suggests that decreased numbers of follow-up radiographs may be acceptable, without changes in management. ^, Children approaching skeletal maturity who have Neer and Horwitz grades III and IV fractures or angulation of 45 degrees or greater may be considered for reduction and fixation. ^{, , , ,}

Reduction

In general, reduction is reserved for severely displaced or severely angulated fractures in older children or those in varus with the greater tuberosity above the level of the cartilage surface. Potential blocks to reduction include the periosteum, capsule, and long head of biceps tendon. ^, Numerous reduction maneuvers have been recommended and can be attempted in the emergency room with sedation, although some may defer any reduction for the operating room setting, where maximal sedation with muscle relaxation can be safely achieved, and a smooth transition to open reduction and fixation techniques can be pursued if the results of attempted closed reduction do not yield satisfactory results. Most fractures can be treated with gentle traction coupled with abduction, ER, and flexion of the shoulder. Neer and Horwitz recommended attempting reduction by placing the shoulder into 90 degrees of forward flexion, abduction, and ER. Others have recommended reduction with 135 degrees of abduction and 30 degrees of flexion and ER, with the fracture manipulated directly to obtain reduction. ^,

If adequate reduction with acceptable radiographic parameters for translation and angulation is achieved, any of several immobilization techniques may be used. Immobilization methods described in the literature include the sling and swathe ( Fig. 6.8 ), two-prong splint, thoracobrachial bandage, shoulder spica cast, Statue of Liberty cast, and hanging arm cast. ^{, , , ,} However, because some degree of ER and abduction is usually necessary to obtain the reduction, a sling construct that achieves a component of this positioning, such as a sling with an abduction pillow or with an ER pillow (“gunslinger brace”), is generally more appropriate than placing in the internally rotated, adducted position of standard slings or sling and swathe constructs.

Clinical photograph of a 9-year-old girl wearing a sling and swathe used in the treatment of proximal humerus fractures. A stockinette is padded at pressure points with cast padding and held in position with safety pins.

Operative treatment

Operative management is infrequently indicated for younger children with fractures of the proximal humerus. However, occasionally, some severely displaced fractures are not amenable to reduction due to soft tissue interposition. Specifically, the tendon of the long head of the biceps becomes interposed between fracture fragments in up to 10% of cases and precludes closed reduction. These fractures often require an open reduction and internal fixation. Other indications for operative management include failure to obtain a closed reduction within acceptable limits of angulation and translation ( Fig. 6.9 ), as outlined previously, segmental fractures, floating shoulder injuries, displaced intra-articular fractures, open fractures requiring debridement, fracture-dislocations, and concomitant neurovascular injury.

An 11-year-old girl sustained a right proximal humerus fracture during a fall from a jungle gym. Nonoperative treatment was initiated with a hanging arm cast, but she progressed into further varus alignment (A), with 60 degrees of apex anterior deformity noted on the axillary view (B) when she presented 4 weeks post injury. She had a painless firm block to motion with a 40-degree abduction deficit with the scapula stabilized, which was confirmed under anesthesia (C). Open reduction through a deltopectoral approach was performed and fixation achieved with two 2.8-mm terminally threaded pins (D–E), which were cut and left buried. Pins were removed 4 weeks postoperatively and physical therapy was initiated. Advanced healing was noted at 10 weeks; the patient had full, painless range of motion and anatomic radiographic alignment as seen on external rotation (F), scapular-Y (G), and axillary (H) views.

(Courtesy Peter D. Fabricant, MD, MPH.)

When a child or, more commonly, an adolescent is brought to the operating room, a closed reduction with fluoroscopic guidance may be attempted prior to transitioning to open reduction. Because general anesthesia affords a level of muscular relaxation in the patient not obtained in a previous reduction attempt in the emergency room, closed reduction can often be successful and allow for percutaneous fixation techniques, described later. If an adequate reduction cannot be obtained, open reduction of proximal humeral fractures is most commonly performed through a standard deltopectoral approach. However, compared with the extensive deltopectoral approach often necessary for open shoulder reconstructions, a somewhat limited skin incision, although adhering to principles of the deltopectoral interval, may be used to gain direct access for adequate fracture reduction of the proximal humerus. One significant advantage of achieving an anatomic or near-anatomic reduction through surgery is that it lessens the amount of time needed for osseous remodeling.

As with proximal humerus fracture treatment in adults, the anterolateral deltoid split has also gained some interest in adolescents as well and may be ideal for access to screw fixation of proximal humerus fractures, which represents a thoughtful alternative to K-wire fixation ( Fig. 6.10 ). For adolescents with 1 to 2 years, or less, of growth remaining, concerns over growth deformity or upper extremity length discrepancy associated with transphyseal screw placement in the proximal humeral physis are minimal. Moreover, screws allow for avoidance of skin issues and office-based pin removal, both of which are associated with percutaneous techniques.

A 13-year-old, postpubertal, left arm–dominant male hockey player was checked into the boards and sustained a left proximal humerus fracture with marked varus alignment (A). Mini-open reduction via a deltoid split in the anterolateral acromial interval was performed. Fixation was achieved with percutaneous cannulated screws with blunt dissection to bone and soft tissue protection to avoid axillary nerve injury (retrograde screw) and screw head recession lateral to the rotator cuff insertion to prevent subacromial impingement (anterograde screw). Intraoperative fluoroscopy in external rotation (B) and internal rotation (C) confirmed anatomic reduction and appropriate screw placement. The patient was immobilized for 1 week in a sling prior to beginning range-of-motion exercises. Strength training was initiated at 4 weeks, and the patient had full regained full strength and range of motion at 8 weeks and was cleared to sports after confirmation of radiographic healing (D).

(Courtesy Peter D. Fabricant, MD, MPH.)

The most common approach to fixation for a reduced proximal humerus fracture in children and adolescents is percutaneous pin fixation, placed in the lateral metaphyseal-diaphyseal junction and advanced retrograde into the humeral head. ^{, ,}

With this technique, small (1 cm) incisions to allow for percutaneous pin placement, or mini-open incisions (1 to 3 cm) to accommodate multiple pins, are used ( Fig. 6.11 ). However, care must be taken to avoid the axillary nerve laterally and anteriorly, as well as other neurovascular structures more medially. The actual bony pinning technique can be challenging because the optimal trajectory is steep, and the pin starting point may migrate proximally while drilling. Therefore use of a soft tissue protector may be helpful in both avoiding soft tissue injury, as well as controlling pins that are apt to skive from their starting point. An alternative technique is drilling a hole in the lateral cortex with a 4.5-mm drill bit, which allows for easier adjustments to pin position and potentially steeper entry points, although pin stability is lessened somewhat. Although smooth pins are usually used, they have a higher risk of loosening than threaded pins, so adequate purchase must be obtained and confirmed in the humeral head. However, if the pin tips are advanced into the subchondral bone of articular portion of the head, meticulous attention to fluoroscopic confirmation of safe positioning, with rotation of the arm and multiple views, is essential to avoid chondral damage. Two to three retrograde pins are generally sufficient to obtain fracture stability after reduction, but anterograde pins may be additionally or alternatively placed through the rotator cuff and greater tuberosity into the medial cortex of the distal fracture fragment. In this scenario, care must be taken not to advance through the cortex more than 1 to 2 mm, due to the neurovascular structures that sit just medial to the proximal diaphysis. Small external fixator pins with threaded tips can be alternatively used, with or without a fixator assembly, but have been described much less commonly.

Technique of percutaneous pinning of a proximal humeral metaphyseal fracture from a distal approach to avoid the axillary nerve. (A) Anteroposterior (AP) radiograph demonstrating a displaced proximal humerus metaphyseal fracture. (B–C) Once satisfactory reduction is obtained, pins are inserted distally through the deltoid and advanced in an inferior-to-superior direction through a drill sleeve to protect the axillary nerve. (D) AP radiograph after pin removal showing a healed fracture, which has started to remodel.

(From Rockwood CA, Wilkins KE, Beaty J, eds. Fractures in Children . Philadelphia: JB Lippincott; 1996.)

As an alternative to retrograde percutaneous pins and open screw placement, use of retrograde flexible intramedullary nails is a technique favored by some to stabilize proximal humerus fractures in children ( Fig. 6.12 ). ^, In this technique, the nails are introduced in the distal humerus metaphysis and cut close to the bone to allow for later removal. Unlike percutaneous pins, which are most commonly removed in the office between 4 and 5 weeks postoperatively, the intermedullary nails provide stability for the entirety of the fracture healing period.

(A) Radiograph of an 11-year-old boy with multiple traumas, including bilateral femoral fractures and a right proximal humerus fracture. (B) The proximal end of the right humerus was treated by closed reduction with titanium elastic nail fixation to facilitate early mobility, with a nail insertion site in the distal humerus, just proximal to the olecranon fossa. (C) The fracture was stabilized well with this internal splint.

(Courtesy Richard L. Munk, MD.)

Greater or lesser tuberosity fracture treatment

The lesser tuberosity is the site of the insertion of the subscapularis, and good results have been reported with the nonoperative management of lesser tuberosity fractures with minimal displacement. ^{, ,} However, several authors have advocated open reduction and internal fixation of displaced fragments in the acute setting. ^{, ,} Ogawa and Takahashi reported better results with operative management of lesser tuberosity fractures. Options for fracture fixation depend on the size of the avulsed fragment. In most cases, bone fragments are thin cortical fragments, in which case suture fixation or suture anchor fixation is adequate. Screw fixation may be performed in fractures with larger fragments. Good results have been reported after arthroscopic treatment of lesser tuberosity fractures and subscapularis tears.

Greater tuberosity fractures in young children, particularly those that are nondisplaced, can often be treated nonoperatively with good outcomes. In adolescents a displaced greater tuberosity fracture often requires open reduction and internal fixation, with repair of any tears of the rotator cuff to prevent subsequent subacromial impingement.

Fracture-dislocations of the proximal humerus are extremely rare injuries in children. However, they should be managed following the principles of adult urgent-emergent open reduction and fracture stabilization to minimize the risk of osteonecrosis. ^,

Authors’ preferred treatment

Nonoperative

Most proximal humerus fractures, including physeal fractures, can be managed nonoperatively. Our preferred method for treatment depends on the age of the patient. In neonates and infants, we manage most fractures with simple immobilization, often by use of a soft elastic bandage to secure the humerus to the infant’s torso. In older children with a proximal humerus fracture, we treat Neer and Horowitz grades I and II fractures and those with less than 45 degrees of angulation nonoperatively, with the exception of those in varus with the greater tuberosity above the level of the cartilage surface. Most fractures can be treated with simple sling immobilization alone, although initial management in the ER may include a swathe with an elastic bandage for comfort. Approximately 1 to 2 weeks after injury, when a follow-up radiograph is warranted to confirm maintenance of fracture fragment positioning, a change to a simple sling or more comfortable sling and swathe construct may be warranted (see Fig. 6.8 ).

Operative

We treat fractures in patients 12 years old and older with greater than 45 degrees of angulation or Neer and Horowitz grades I and II fractures with closed reduction and percutaneous pin fixation or internal screw fixation. Although some report supine positioning as adequate, we favor “sloppy beach chair” (;45 degrees of flexion of the head of the table) or “true” beach chair positioning (;60 degrees) on a radiolucent table. A bump is usually placed under the scapula to allow for better access to the anterior glenohumeral joint and greater ROM of the shoulder. The arm is sterilely prepped and draped free, and the fracture is reduced under fluoroscopic guidance, using the maneuvers described earlier. If closed reduction is unsuccessful, either the deltopectoral interval or an anterolateral deltoid split can be opened to facilitate reduction.

Once adequate reduction is achieved, percutaneous pins are inserted through the lateral cortex. We prefer the smooth pins, which facilitate simple, generally painless, office-based removal at 4 to 5 weeks postoperatively, by which time adequate callus has formed to prevent fracture displacement. These pins are directed across the fracture site and into the head of the humerus, with the pin tips usually just short of the subchondral bone. Two or three pins are inserted until the fracture has been satisfactorily stabilized ( Fig. 6.13 ). In older children (i.e., 13 years and older), fully threaded screw fixation techniques are considered because transphyseal placement does not have clinically significant long-term growth disturbances or sequelae. The extremity is placed in a shoulder immobilizer for 2 to 3 weeks. For percutaneous pin fixation, a visit 1 to 2 weeks postoperatively can allow for radiographic confirmation of maintained fracture fragment and pin position, as well as a pin site check, to avoid significant skin breakdown or infection.

A 14-year-old male quarterback sustained an injury to his right shoulder when tackled. Anteroposterior (A) and lateral (B) radiographs show a displaced and angulated fracture of the proximal humerus. An attempt at treatment in a hanging arm cast failed to provide acceptable alignment, and a closed reduction was performed under anesthesia. (C) The fracture was deemed unstable despite a near-anatomic reduction, so percutaneous pinning was performed. The postoperative course was uneventful. (D) A radiograph taken 6 weeks into the patient’s postoperative course after pin removal shows excellent fracture healing.

Complications

Both early and late complications from proximal humerus fractures have been reported. Early complications result directly from the fracture. These can be serious and can develop into potentially limb-threatening injuries, including neurovascular compromise. Typically, these are injuries to the brachial plexus from fracture dislocation, which can often be diagnosed early after injury, with loss of strength and sensation in a specific nerve distribution. Most of these injuries are neurapraxias that recover within 4 to 6 months. If no sign of recovery is noted, an electromyography study is warranted to document whether there is tangible improvement in the status of the nerve palsy. If no improvement is noted, surgical exploration and possible repair or nerve grafting of the involved structure may be indicated.

Vascular injuries are uncommon but have been reported. Implant-related complications, such as hardware migration, have also been reported after the internal fixation of proximal humerus fractures. ^, Loss of motion is another complication, seen particularly in patients who were treated surgically.

Late complications are often sequelae of the original injury. Humerus varus usually occurs in children and neonates after a history of trauma, infection, or metabolic or hematologic conditions ( Fig. 6.14 ). ^{, ,} As previously mentioned, these patients may occasionally exhibit significant limitation of passive and active motion in abduction due to subacromial impingement and reduced power from limited rotator cuff excursion, necessitating corrective osteotomy ( Fig. 6.15 ). ^{, , ,}

Proximal humeral varus resulting from an infection at 11.5 years of age. (A) Early signs of infection and periosteal reaction (arrow) . (B) Varus and marked shortening.

(From Rockwood CA, Wilkins KE, Beaty J, eds. Fractures in Children . Philadelphia: JB Lippincott; 1996.)

A 15-year-old male with posttraumatic proximal humerus varus malunion; this resulted in difficulty in performing activities of daily living and the inability to participate in sports. (A) Clinical photograph showing a mechanical block to active and passive right shoulder abduction at 110 degrees. (B–C) Anteroposterior (AP) radiographs of the right shoulder, with an obliquely oriented proximal humeral physis and equal heights of the greater tuberosity and an articular surface resulting from 32 degrees of varus malunion, and comparison view of the uninvolved left shoulder, with a normal, transversely oriented proximal humeral physis and articular surface that is expectedly superior to the height of the greater tuberosity. (D) A 6-month postoperative AP radiograph showing the healed lateral closing wedge osteotomy transfixed with a low-profile 3.5-mm blade plate and the restored normal neck-shaft angle, as well as an anatomically restored relationship between the greater tuberosity and articular surface. The patient regained full active abduction and returned to full activities.

(Courtesy Daniel W. Green, MD, and Russell F. Warren, MD.)

Growth arrest has been reported in children who sustain physeal fractures and in some pathologic conditions that cross the physis, such as chondroblastomas and bone cysts. ^, Complete physeal arrest has been reported but is relatively rare. More often, these cases do not result in any functional deficit, and most children do not need any form of surgical intervention.

Hypertrophic scar formation is a complication seen after surgical management. ^{, ,} To avoid this, some authors have proposed a more cosmetic axillary approach for the treatment of these injuries; however, full anatomic visualization may be impaired. Osteonecrosis of the humeral head is a rare complication; however, even with osteonecrosis, good outcomes have been reported in the shoulder because it is a non–weight-bearing joint. Glenohumeral subluxation has also been reported in children with proximal humerus fractures ^, ; this often responds well to a period of nonoperative management, sling immobilization, and early rehabilitation.

Glenohumeral instability treatment

The treatment of glenohumeral instability is covered at length elsewhere in this textbook, but clinical features unique to children and adolescents warrant special mention here. Primary, first-time shoulder dislocation and subluxation in children and adolescents is frequently treated nonoperatively with closed reduction, a short period of immobilization, and supervised physical therapy, resulting in an ultimate return to full activity. Surgical intervention is reserved for adolescents with significant bony Bankart lesions, those who experience recurrent dislocations, those who fail conservative management, those with more severe soft tissue injury patterns, such as humeral avulsions of the glenohumeral ligament or glenoid articular disruptions, and those who participate in competitive contact or overhead sports with multiple risk factors for recurrence that elect for surgery after a thoughtful shared decision-making approach. Although some surgeons continue to use open surgical techniques for instability repair (particularly in the presence of large bony lesions, poor-quality tissue, or revision settings), advances in arthroscopic fixation and instrumentation have made arthroscopy the more common standard of care in the adolescent age group. Athletic adolescents and teenagers have good outcomes following arthroscopic stabilization, with 87% reported as returning to competitive sports. However, it is important to note that the rate of recurrent instability is higher in younger patients than in adults, particularly in those with ligamentous laxity, multiple instability episodes, and Hill-Sachs lesions. ^{, ,}

Fractures of the clavicle

Embryology and development

The clavicle is the first long bone in the body to begin ossification, ^{, ,} beginning from two primary ossification centers (medial and lateral) by 5 to 6 weeks of gestation. By 7 to 8 weeks the clavicle has already assumed its overall contour and “S” shape. Most growth (80%) occurs from the medial physis. Despite this early appearance, the clavicle also has the distinction of being the last long bone to complete the ossification process. The lateral epiphysis forms and fuses in a remarkably short time at approximately 18 to 19 years of age. The medial epiphysis is the last epiphysis in the body to initiate ossification, at the age of 18 to 20 years, and the last to complete it, at the age of 23 to 25 years. ^, Therefore, although some authors have suggested that much of the growth of the clavicle is completed by early adolescents, this prolonged ossification process into young adulthood speaks to an underappreciated and quite robust remodeling potential, even among older adolescents, which has larger clinical implications on treatment decision making in adolescents.

Relevant anatomy

The clavicle is an S-shaped bone that articulates medially with the sternum and laterally with the scapula at the acromion. Through minimal motion through the sternoclavicular and acromioclavicular (AC) joints, the clavicle functionally links the axial skeleton and the appendicular skeleton, acting as a simple strut to hold the shoulder girdle at length on the chest wall and allow for scapulothoracic motion. The medial two-thirds of the bone is round and tubular; the lateral third is flat. The anterosuperior aspect of the clavicle is subcutaneous. The subclavian vessels and brachial plexus lie posterior and inferior to the clavicle near the junction of the middle and lateral thirds ( Fig. 6.16 ).

Relationship of the clavicle and scapula to the brachial plexus and subclavian artery.

(From Sarwark JF, King EC, Luhmann SJ. Proximal humerus, scapula, and clavicle. In: Rockwood CA, Wilkins KE, Beaty J, eds. Fractures in Children , 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2006:703–771.)

Numerous muscles and ligaments attach to the clavicle. Anteriorly, the pectoralis major originates on the medial two-thirds of the clavicle and the deltoid on the lateral third. Posteriorly, the trapezius muscle inserts onto the lateral third of the clavicle. The clavicular head of the sternocleidomastoid muscle originates on the superior surface. The subclavius muscle and enveloping clavipectoral fascia attach to the inferior surface.

By providing stability for the muscular and ligamentous origins of the principal mobilizers of the upper arm, particularly the pectoralis major and deltoid muscles, the clavicle plays an indirect role in the overall motion and function of the upper extremity. However, its principal role is that of a stabilizing strut between the axial skeleton and appendicular skeleton. In addition, through the sternoclavicular joint, the clavicle itself is responsible for a small amount of motion. Upward elevation of the clavicle of approximately 30 to 35 degrees can contribute to shoulder abduction. The clavicle can also protract and retract approximately 35 degrees in the anterior-to-posterior plane, and it can rotate 45 to 50 degrees about its long axis.

Laterally, the clavicle articulates with the acromion of the scapula through the AC joint, which is a diarthrodial joint, surrounded by a relatively weak capsule and supported superiorly and inferiorly by the AC ligaments. In a child the lateral third of the clavicle is surrounded circumferentially by thick periosteum that confers stability against fracture displacement. The capsule and AC ligaments blend with this periosteum. The primary stabilizing ligaments, the conoid and trapezoid portions of the coracoclavicular (CC) ligaments, arise from the coracoid and attach to the lateral end of the clavicle and its thick inferior periosteum.

Medially, the clavicle articulates with the manubrium of the sternum and the first rib through the sternoclavicular joint. This joint is also diarthrodial, and, similar to the acromioclavicular joint, it lacks inherent structural stability. The joint is stabilized by a group of ligaments that include the intra-articular disk ligament, the anterior and posterior capsular ligaments, the interclavicular ligament, and the costoclavicular ligament ( Fig. 6.17 ). Although the anterior capsular ligament is heavier and stronger than the posterior, the posterior sternoclavicular ligaments have been shown to act as the primary stabilizing force to AP translation, which has implications for treatment decisions in the setting of sternoclavicular instability. The capsular ligaments attach mainly to the epiphysis of the medial clavicle; therefore the physis is extra-articular and susceptible to injury during injuries to the medial clavicle. The sternoclavicular joint overlies several important mediastinal structures, including the great vessels, the vagus and phrenic nerves, and the trachea and esophagus.

Normal anatomy of the sternoclavicular joint.

Associated injuries

Although exceedingly rare in children, in part because of the thick periosteum and relative stability of the clavicle even following fracture, clavicle fracture can be associated with serious vascular injuries, including subclavian and axillary artery disruption; subclavian vessel compression, thrombosis, and pseudoaneurysm; and arteriovenous fistulas. There have been reports of anomalous external jugular veins anterior to the clavicle that were subject to injury. Both early and late brachial plexus neuropathy has also been reported in association with injuries to the clavicle. Thorough neurovascular examination of the upper extremity is warranted to rule out these injuries.

Fractures of the clavicle secondary to high-energy injuries, such as motor vehicle accidents or falls from heights, can be associated with injuries to the ipsilateral lung and chest wall, such as pneumothorax, hemothorax, pulmonary contusion, and rib fractures. Additional injuries to the ipsilateral upper extremity and shoulder girdle are also possible in high-energy injury mechanisms.

Posterior displaced fractures of the medial clavicle and posterior dislocations of the sternoclavicular joint are at particular risk for concomitant injury to the retrosternal structures in the mediastinum, including the great vessels, esophagus, and trachea. A child presenting with medial clavicle or midline blunt trauma with associated difficulty in speaking, breathing, or swallowing should raise suspicion of a sternoclavicular injury that warrants an emergent workup. Signs of venous congestion and diminished distal pulse can also suggest associated injuries, which can be life threatening.

Fractures of the clavicle are rarely associated with atlantoaxial (C1 to C2) rotatory subluxation ( Fig. 6.18 ). ^, Clinically, the head is tilted laterally toward and rotated away from the fractured clavicle. The diagnosis of C1 to C2 rotatory subluxation is difficult because of the masking of the torticollis by the acute symptoms of the fractured clavicle, but it should be suspected when there is asymmetric cervical ROM. The diagnosis is best confirmed by dynamic CT.

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