Elbow Trauma Elbow Trauma 6 of all fractures

Elbow Trauma

Elbow Trauma • 6% of all fractures and dislocations involve elbow • Most common fractures differ between adults and children – M. C. in adults- radial head and neck fxs. – M. C. in children- supracondylar fxs. • Complex anatomy requires 4 views for adequate interpretation – AP in extension, medial oblique, lateral and axial olecranon (Jones view)

Normal Elbow Anatomy • Very important to be aware of pediatric growth centers – CRITOE http: //med_practice. byethost 7. com/wp 2/? p=21 http: //www. radiologyassistant. nl/en/4214416 a 75 d 87

Normal Alignment • Anterior humeral line- line drawn along anterior surface of humeral cortex should pass through the middle third of the capitellum • Radiocapitellar line- Line drawn through the proximal radial shaft and neck should pass through to the articulating capitellum http: //imageinterpretation. co. uk/elbow. html

Signs of Fracture • Usual signs may not be readily visible – Fracture line, cortical disruption, etc. • Soft tissue signs can indicate fracture – Fat pad sign • On lateral, might see fat pad parallel to anterior humeral cortex, but should never see posterior fat pad • With effusion, anterior may be displaced and will be shaped like a sail (sail sign)

Fat Pad Sign • Posterior fat pad is normally buried in olecranon fossa and not visible – Becomes elevated and visible with joint uffusion • Effusion (acute capsular swelling) can be from any origin (hemorrhagic, inflammatory, infectious, traumatic, etc. ) • Ant. fat pad may be obliterated, so post. Fat pad is more reliable when visible

Distal humerus fractures • 95% extend to articular surface • Classified according to relationship with condyle and shape of fracture line – Supracondylar, intercondylar, condylar and epicondylar

Supracondylar Fractures • Most common elbow fracture in children (60%) • Fracture line extends transversely or obliquely through distal humerus above the condyles • Distal fragment usually displaces posteriorly Normal

Intercondylar fracture • Fracture line extends between medial and lateral condyles and extends to supracondylar region – Results and T or Y shaped configuration for fracture • Called trans-condylar if it extends through both condyles

Epicondylar fracture • Usually avulsion from traction of respective common flexor (medial) or extensor (lateral) tendons • Medial epicondyle avulsion common in sports with strong throwing motion (little leaguer’s elbow)

Fractures of Proximal Ulna • Olecranon fx. - direct trauma or avulsion by triceps tendon • Coronoid process fx. - avulsion by brachialis or impaction into trochlear fossa – Rarely isolated; usually associated with post. elbow dislocation

Fractures of Proximal Radius • M. C. adult elbow fx. (50%) • FOOSH transmits force causing impaction of radial head into capitellum • Chisel fracture- incomplete fracture of radial head that extends to center of articular surface • Usual rad. signs (fx. Line, articular disruption) may not be visible – May be occult; fat pad sign is good indicator of occult fx.

Fractures of the forearm • Isolated ulnar fractures • Isolated radial fractures • Bony rings usually can't be fractured in one place without disruption somewhere else in the ring • 60% or forearm fractures involve both bones (BB fractures) • These fractures usually have associated displacement with angulation and rotation

Isolated Ulnar Fractures • Distal shaft (Nightstick fx. )- direct trauma http: //radiographics. rsna. org/content/24/4/1009/F 31. expansion. html • Proximal shaft (Monteggia’s fx. )fx. of proximal ulna with dislocation of radius http: //www. wheelessonline. com/ortho/monteggias_fracture

Isolated Radial Fractures • Most frequent is a Galeazzi’s fx. (reverse Monteggia’s fx. ) – Fracture of distal radial shaft with dislocation of distal radioulnar joint – Rare, but serious injury http: //www. learningradiology. com/archives 05/COW%20157 -Galeazzi%20 Fx/galeazzicorrect. htm

Dislocations of Elbow • 3 rd m. c. dislocation in adults behind shoulder and interphalangeal joints – More common in children • Classified according to displacement of radius an ulna relative to humerus – Posterior, posterolateral, anterior, medial and anteromedial • Posterior and posterolateral or more most common – 85 -90% of all elbow locations – 50% have associated fractures

Pulled Elbow • AKA nursemaid’s elbow • Occurs when child’s hand is pulled, tractioning arm and causing radial head to slip out from under annular ligament and trapping the ligament in the radiohumeral articulation • Immediate pain; stuck in mid-pronation due to pain • No radiographic pain • Supination reduces the dislocation and ends pain, usually during positioning of lateral radiograph

References • Yochum, T. R. (2005) Yochum and Rowe’s Essentials of Skeletal Radiology, Third Edition. Lippincott, Williams and Wilkins: Baltimore.