Pediatric Forearm Fractures J.J. Prosser
Dec 31, 2015
Pediatric Forearm Fractures
J.J. Prosser
Incidence
• 3.4% of all children’s fractures
• Bimodal peak with boys – 9 and 13 years old
• Girls – 5 years old
0ssification
Radial and ulnar shafts ossify during the eighth week of gestation
Distal radial epiphysis – age 1
Distal ulnar epiphysis – age 6
Radial head – age 5-7
Olecranon – age 9-10
They all close between the ages of 16-18
Anatomic Area
Distal third – 75%
Middle third – 18%
Proximal third – 7%
Osteology
The periosteum is very strong and thick in a child
It is generally disrupted on the convex side, while an intact hinge remains on the concave side
This is an important point when considering closed reduction
Biomechanics
The radius shortens with pronation and lengthens with supination
Malreduction of 10 degrees in the middle third limits rotation by 20-30 degrees
Bayonet apposition does not reduce forearm rotation
Deforming Muscle Forces
Proximal third Biceps and supinator – flexion and supination of proximal
fragmentPronator teres and quadratus – pronate distal fragment
Middle thirdSupinator, biceps, and pronator teres – proximal fragment is
neutralPronator quadratus – pronates distal fragment
Distal thirdBrachioradialis – dorsiflex and radial deviate distal
fragment
Mechanism of injury
Indirect – fall onto an outstretched hand
Direct – blow from an object onto the radial and ulnar shaft
Rotation Pronation – flexion injury(posterior angulation)
Supination – extension injury(anterior angulation)
Clinical evaluation
History – age, mechanism of injury, and other areas of pain
Physical exam – skin integrity, neurovascular status, and examination of elbow and wrist joints
Radiographic evaluation
AP and lateral of forearm, wrist, and elbow
The bicipital tuberosity is the landmark for identifying rotation
Description
Location – proximal, middle, distal
Type Plastic deformation
Incomplete(greenstick)
Compression(torus or buckle)
Complete
Salter-Harris
75% in children 10-16 years old
Uncommon in children < 5 years old
Type II most common – Thurston-Holland fragment
Monteggia
Proximal ulna fracture with dislocation of the radial head0.4% of all forearm fractures in children
Peak incidence between 4 and 10 years old
Ulna fracture usually at junction of proximal/middle thirds
Galeazzi
Middle to distal third radius fracture with disruption of the distal radioulnar jointRare in children
Peak incidence between 9 and 12 years old
Initial management
Correct gross deformityPerform closed reduction and application of a well
molded long arm castForearm reduction after rotation
Proximal third – supinationMiddle third – neutralDistal third – pronation
Split cast if concerned about swelling(uni-valve, bi-valve)
Acceptable deformity
Patients > 10 years old, treat like adult – no deformity accepted
Patients < 10 years old;Angular deformities – 1 degree/month
- 10 degrees/year
Rotational deformities – none
Bayonet apposition – 1cm
Undisplaced fractures
Long arm cast – 4-6 weeks until nontender
Elbow at 110-120 degrees of flexion
Plastic deformation
Children < 4 years old or with deformities < 20 degrees, same as undisplaced
Greenstick fractures
Complete the fracture to decrease risk of angular deformity
Carefully crack the intact cortex while preventing displacement
Well molded long arm cast
Complete displacement
Attempt closed reduction and long arm cast with pancake molding
If the fracture is irreducible, ORIF may be indicated
Operative management
IM fixation – Enders nail, K-wires
- limited exposure at fracture site may be required for reduction
Plate fixation – prime indication is one of refracture in which the intramedullary canal has a high risk of being obstructed
Problems
Malunion – over 60% have rotational losses >20 degrees
Refracture – incidence of 12% - refrain from sports 1 month after cast
removalNonunion – rare in children - high energy, open, infection - ulnar > radialNeurovascular injuries – posterior interosseous nerve
damage with Monteggia Type III
Problems continued
Compartment syndrome – pain aggravated by passive motion - pressure > 30mmHg - fasciotomyInfection - > 6 hours before debridement(exponential growth)RSD – rare in children - burning pain, hyperesthesia, and swelling - resolves 6-12 months after injuryOvergrowth – 6-8 months after injury - averages 6-7mm