Pediatric Shoulder



Pediatric Shoulder





PROXIMAL HUMERUS FRACTURES


Epidemiology



  • These account for <5% of fractures in children.


  • Incidence ranges from 1.2 to 4.4 per 10,000 per year.


  • They are most common in adolescents owing to increased sports participation and are often metaphyseal, physeal, or both.


  • Neonates may sustain birth trauma to the proximal humeral physis, representing 1.9% to 6.7% of physeal injuries (Fig. 43.1).


Anatomy



  • Eighty percent of humeral growth occurs at the proximal physis, giving this region great remodeling potential.


  • There are three centers of ossification in the proximal humerus:



    • Humeral head: This ossifies at 6 months.


    • Greater tuberosity: This ossifies at 1 to 3 years.



    • Lesser tuberosity: This ossifies at 4 to 5 years.


    • The greater and lesser tuberosities coalesce at 6 to 7 years and then fuse with the humeral head between 7 and 13 years of age.


  • The joint capsule extends to the metaphysis, rendering some fractures of the metaphysis intracapsular (Fig. 43.2).


  • The primary vascular supply is via the anterolateral ascending branch of the anterior circumflex artery, with a small portion of the greater tuberosity and inferior humeral head supplied by branches of the posterior circumflex artery.


  • The physis closes at ages 14 to 17 years in girls and at ages 16 to 18 years in boys.


  • The physeal apex is posteromedial and is associated with a strong, thick periosteum.


  • Type I physeal fractures occur through the hypertrophic zone adjacent to the zone of provisional calcification. The layer of embryonal cartilage is preserved, leading to normal growth.


  • Muscular deforming forces: The subscapularis attaches to the lesser tuberosity. The remainder of the rotator cuff (teres minor, supraspinatus, and infraspinatus) attaches to the posterior epiphysis and greater tuberosity. The pectoralis major attaches to the anterior medial metaphysis, and the deltoid connects to the lateral shaft.






FIGURE 43.1 Hyperextension or rotation of the ipsilateral arm may result in a proximal humeral or physeal injury during birth. (From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2006.)






FIGURE 43.2 The anatomy of the proximal humerus. (From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2006.)


Mechanism of Injury



  • Indirect: Resulting from a fall backward onto an outstretched hand with the elbow extended and the wrist dorsiflexed. Birth injuries may
    occur as the arm is hyperextended or rotated as the infant is being delivered. Shoulder dystocia is strongly associated with macrosomia from maternal diabetes.


  • Direct: Resulting from direct trauma to the posterolateral aspect of the shoulder.


Clinical Evaluation



  • Newborns present with pseudoparalysis with the arm held in extension. A history of birth trauma may be elicited. A fever is variably present. Infection, clavicle fracture, shoulder dislocation, and brachial plexus injury must be ruled out.


  • Older children present with pain, dysfunction, swelling, and ecchymosis, and the humeral shaft fragment may be palpable anteriorly. The shoulder is tender to palpation, with a painful range of motion that may reveal crepitus.


  • Typically, the arm is held in internal rotation to prevent anteromedial pull of the distal fragment by the pectoralis major.


  • A careful neurovascular examination is required, including assessment of the axillary, musculocutaneous, radial, ulnar, and median nerves.


Radiographic Evaluation



  • Anteroposterior (AP), lateral (in the plane of the scapula; “Y” view), and axillary views should be obtained, with comparison views of the contralateral side if necessary.


  • Ultrasound: This may be necessary in the newborn because the epiphysis is not yet ossified.


  • Computed tomography may be useful to aid in the diagnosis and classification of posterior dislocations and complex fractures.


  • Magnetic resonance imaging is more useful than bone scan to detect occult fractures because the physis normally has increased radionuclide uptake, making a bone scan difficult to interpret.


Classification


Salter-Harris (Fig. 43.3)

Type I: Transphyseal fracture; usually a birth injury

Type II: Transphyseal fracture that exits through the metaphysis; usually occurring in adolescents (>12 years old); metaphyseal fragment always posteromedial

Type III: Transphyseal fracture that exits through the epiphysis uncommon; associated with dislocations

Type IV: Rare; fracture that traverses the epiphysis and the physis, exiting the metaphysis; associated with open fractures







FIGURE 43.3 Physeal fractures of the proximal humerus. (A) Salter-Harris I. (B) Salter-Harris II. (C) Salter-Harris III. (D) Salter-Harris IV. (From Bucholz RW, Heckman JD, Court-Brown C, et al., eds. Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2006.)


Neer-Horowitz Classification of Proximal Humeral Plate Fractures

Grade I: <5 mm displacement

Grade II: Displacement less than one-third the width of the shaft

Grade III: Displacement one-third to two-thirds the width of the shaft

Grade IV: Displacement greater than two-thirds the width of the shaft, including total displacement



Prognosis



  • Neer-Horowitz grades I and II fractures do well because of the remodeling potential of the proximal humeral physis.


  • Neer-Horowitz grades III and IV fractures may be left with up to 3 mm of shortening or residual angulation. This is well tolerated by the patient and is often clinically insignificant.


  • As a rule, the younger the patient, the higher the potential for remodeling and the greater the acceptable initial deformity.



CLAVICLE FRACTURES


Epidemiology



  • Most frequent long bone fracture in children (8% to 15% of all pediatric fractures).


  • These occur in 0.5% of normal deliveries and 1.6% of breech deliveries (they account for 90% of obstetric fractures). The incidence of birth fractures involving the clavicle ranges from 2.8 to 7.2 per 1,000 term deliveries, and clavicular fractures account for 84% to 92% of all obstetric fractures.


  • In macrosomic infants (>4,000 g), the incidence is 13%.


  • Eighty percent of clavicle fractures occur in the midshaft, most frequently just lateral to the insertion of the subclavius muscle, which protects the underlying neurovascular structures.


  • Ten percent to 15% of clavicle fractures involve the lateral aspect, with the remainder representing medial fractures (5%).


Anatomy



  • The clavicle is the first bone to ossify; this occurs by intramembranous ossification.


  • The secondary centers develop via endochondral ossification:



    • The medial epiphysis, where 80% of growth occurs, ossifies at ages 12 to 19 years and fuses by ages 22 to 25 years (last bone to fuse).


    • The lateral epiphysis does not ossify until it fuses at age 19 years.


  • Clavicular range of motion involves rotation about its long axis (approximately 50 degrees) accompanied by elevation of 30 degrees with full shoulder abduction and 35 degrees of anterior-posterior angulation with shoulder protraction and retraction.


  • The periosteal sleeve always remains in the anatomic position. Th erefore, remodeling is ensured.



Mechanism of Injury



  • Indirect: Fall onto an outstretched hand.


  • Direct: This is the most common mechanism, resulting from direct trauma to the clavicle or acromion; it carries the highest incidence of injury to the underlying neurovascular and pulmonary structures.


  • Birth injury: Occurs during delivery of the shoulders through a narrow pelvis with direct pressure from the symphysis pubis or from obstetric pressure directly applied to the clavicle during delivery.


  • Medial clavicle fractures or dislocations usually represent Salter-Harris type I or II fractures. True sternoclavicular joint dislocations are rare. The inferomedial periosteal sleeve remains intact and provides a scaffold for remodeling. Because 80% of the growth occurs at the medial physis, there is great potential for remodeling.


  • Lateral clavicle fractures occur as a result of direct trauma to the acromion. The coracoclavicular ligaments always remain intact and are attached to the inferior periosteal tube. The acromioclavicular ligament is always intact and is attached to the distal fragment.


Clinical Evaluation



  • Birth fractures of the clavicle are usually obvious, with an asymmetric, palpable mass overlying the fractured clavicle. An asymmetric Moro reflex is usually present. Nonobvious injuries may be misdiagnosed as congenital muscular torticollis because the patient will often turn his or her head toward the fracture to relax the sternocleidomastoid muscle.


  • Children with clavicle fractures typically present with a painful, palpable mass along the clavicle. Tenderness is usually discrete over the site of injury, but it may be diffuse in cases of plastic bowing. There may be tenting of the skin, crepitus, and ecchymosis.


  • Neurovascular status must be carefully evaluated because injuries to the brachial plexus and upper extremity vasculature may occur. Rule out brachial plexus palsy.


  • Pulmonary status must be assessed, especially if direct trauma is the mechanism of injury. Medial clavicular fractures may be associated with tracheal compression, especially with severe posterior displacement.


  • Differential diagnosis

Jun 17, 2016 | Posted by in ORTHOPEDIC | Comments Off on Pediatric Shoulder

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