Lateral Condyle Fracture - Pediatric - Pediatrics

Introduction

Overview
- pediatric lateral condyle fractures are the second most common fractures in the pediatric elbow and are characterized by a higher risk of nonunion, malunion, and AVN than other pediatric elbow fractures.
  - treatment is dictated by the degree of articular displacement and may require CRPP or open reduction.
Epidemiology
- incidence
  - 17% of all distal humerus fractures in the pediatric population
  - 2nd most common elbow fracture after supracondylar
- demographics
  - typically occurs in patients aged 6 years
- location
  - most commonly are Salter-Harris IV fracture patterns of the lateral condyle
Pathophysiology
- mechanism of injury
  - pull-off theory
    - avulsion fracture of the lateral condyle that results from the pull of the common extensor musculature
  - push-off theory
    - fall onto an outstretched hand causes impaction of the radial head into the lateral condyle causing fracture
- pathoanatomy
  - fractures originate proximally at the posterior aspect of the distal humerus metaphysis and extend distally and anteriorly across the physis and epiphysis into the elbow joint
  - fracture may extend medially into the trochlear groove, making the elbow unstable and prone to dislocation
- posteromedial elbow dislocation
  - result of FOOSH with slight elbow flexion and adduction force
  - rare concomitant injury pattern
Prognosis
- outcomes have historically been worse than supracondylar fractures
  - articular nature, missed diagnosis, and higher risk of malunion/nonunion
- associated posteromedial elbow dislocations
  - prolonged return of ROM
  - final ROM similar to isolated lateral condyle fracture

Anatomy

Ossification centers of elbow
- lateral (external) epicondyle
  - ossifies/appears at age 11 years
  - fuses at age 12-14 years
- age of ossification/appearance and age of fusion are two independent events that must be differentiated

Ossification center	Years at ossification (appear on xray) (1)	Years at fusion (appear on xray) (1)
Capitellum	1	12-14*
Radius	3	14-16
Internal (medial) epicondyle	5	16-18
Trochlea	7	12-14*
Olecranon	9	15-17
External (lateral) epicondyle	11	12-14*
(1) +/- one year, varies between boys and girl. C-R-I-T-O-E to remember age of ossification. CTE-R-O-I to remember age of fusion (capitellum, trochlea and external (lateral) epicondyle fuse together at puberty. Together they fuse to the distal humerus between the ages of 14-16 years old)

Blood Supply
- the brachial artery lies anteriorly in the antecubital fossa
- most of the blood supply of the distal humerus comes from the anastomotic vessels that course posteriorly
Lateral collateral ligament
- remains intact and attached to lateral condyle fragment proximally and radial neck distally

Classification

Milch Classification-controversial
Type I	Fracture line is lateral to trochlear groove (less common, elbow is stable as fracture does NOT enter trochlear groove)
Type II	Fracture line extends medially into trochlear groove (more common, more unstable)

Fracture Displacement Classification-Weiss, et al
Type 1	<2mm, indicating intact cartilaginous hinge	Casting
Type 2	>2 mm < 4 displacement, intact articular cartilage on arthrogram	Closed reduction and fixation
Type 3	>4 mm, articular surface disrupted on arthrogram	Open reduction and fixation

Presentation

History
- fall onto an outstretched hand
Symptoms
- location
  - lateral elbow pain and swelling
- severity
  - may be subtle if fracture is minimally displaced
Physical exam
- inspection
  - exam lacks the obvious deformity often seen with supracondylar fractures
  - swelling and tenderness are usually limited to the lateral side
  - lateral ecchymosis implies a tear in the aponeurosis of the brachioradialis and signals an unstable fracture
- motion
  - may have increased pain with resisted wrist extension/flexion
  - may feel crepitus at the fracture site

Imaging

Radiographs
- recommended views
  - AP, lateral, and oblique views of elbow
    - internal oblique view most accurately shows fracture displacement because fracture is posterolateral
- optional views
  - contralateral elbow for comparison when ossification is not yet complete
  - routine elbow stress views are not recommended due to pain and lack of useful information
- findings
  - fracture fragment most often lies posterolateral which is best seen on internal oblique views
  - in displaced fractures, the capitellum is laterally displaced in relation to radial head
  - posteriorly based Thurston-Holland fragment on the lateral view
Arthrogram
- indications
  - minimally displaced fractures
  - to assess cartilage surface when there is incomplete/absent epiphyseal ossification
  - allows dynamic assessment
CT scan
- indication
  - rarely indicated, only if there is uncertainty as to the type of fracture
MRI
- indication
  - provides the ability to assess the cartilaginous integrity of the trochlea
  - useful for operative planning of delayed or non-unions
- expensive
- require GA/sedation to perform the test
- arthrograms generally preferred to MRI

Differential

Pediatric Elbow Injury Frequency
Fracture Type	% elbow injuries	Peak Age	Requires OR
Supracondylar fractures	41%	7	majority
Radial Head subluxation	28%	3	rare
Lateral condylar physeal fractures	11%	6	majority
Medial epicondylar apophyseal fracture	8%	11	minority
Radial Head and Neck fractures	5%	10	minority
Elbow dislocations	5%	13	rare
Medial condylar physeal fractures	1%	10	rare

Treatment

Nonoperative
- long arm casting x 4-6wks
  - indications
    - only if < 2 mm displacement in all views
    - medial cartilaginous hinge must remain intact
  - technique
    - cast with elbow at approx 90 degrees as long as swelling is mild
    - weekly follow up and radiographs every week x first 3 weeks, including internal oblique view
    - occasionally > 6 weeks of casting is needed
Operative
- CRPP + 3-6 wks in above elbow cast
  - indications
    - fractures with 2 - 4 mm of displacement have intact articular cartilage and can be treated with CRPP
- open reduction and fixation + 3-6 wks in above elbow cast
  - indications
    - > 4mm of displacement
      - open reduction (rather than closed) necessary to align the joint surface
    - joint incongruity
    - fracture non-union
- supracondylar osteotomy
  - indications
    - deformity correction in late-presenting cubitus valgus - rarely needed

Techniques

CRPP
- approach
  - closed reduction perhaps aided by pushing the fragment anteromedially to close the gap
- instrumentation
  - divergent pin configuration most stable
  - screw considered for more rigid fixation
    - allows early motion
    - compresses fracture site
- complications
  - pins are less stiff
  - screw may need to be removed if crossing the physis

ORIF
- approach
  - anterolateral approach as blood supply comes from posteriorly
- soft tissue
  - below the skin, dissection to the joint is most often already accomplished by injury
  - avoid dissection of the posterior aspect of lateral condyle (source of vascularization)
- bone work
  - directly visualize the joint reduction, at times the metaphyseal reduction may not be perfect, as fracture fragment may have plastic deformation
- instrumentation
  - most fractures can be fixed with 2 percutaneous pins (3 if comminuted) in parallel or divergent fashion
  - single screw for large fragments or non-union. bone grafting rarely needed
- complications
  - pins are less stiff
  - screw may need to be removed if crossing the physis

Complications

Stiffness
- incidence
  - most common complication
- risk factors
  - stiffness may be an early sign of a non-union or delayed union
- treatment
  - usually self-resolving
  - by 24 weeks 90% of motion returns and full motion is present by 48 weeks
Delayed Union
- fracture that does not heal with 6 weeks of immobilization
- risk factors
  - fracture that is seen more than 2 weeks after injury
- treatment
  - may be treated with immobilization if minimally displaced
  - surgical treatment if displaced
  - must be followed until radiographic union as nonunion is common in this scenario
Nonunion
- incidence
  - higher rate of nonunion than other elbow fractures
- risk factors
  - nonsurgical management
- mechanism - theoretical
  - constant motion at fracture site from pull of the wrist extensors
  - intra-articular (synovial fluid impede fracture healing)
  - poor metaphyseal circulation to distal fragment
- prevent nonunion by
  - preserving soft tissue attachments to lateral condyle
  - stable internal fixation
- treatment
  - goal is to obtain union of metaphyseal fragment, not restore joint surface
  - may require bone graft
  - ORIF with screw
Cubitus Valgus ± tardy ulnar nerve palsy
- due to lateral physeal arrest or more commonly a nonunion
- slow, progressive ulnar nerve palsy caused by stretch
- incidence
  - 10%
  - less common than cubitus varus
- risk factors
  - significant deformities that cause physeal arrest
- treatment
  - supracondylar osteotomy after skeletal maturity and ulnar nerve transposition
AVN
- incidence
  - occurs 1-3 years after fracture
- risk factors
  - posterior dissection can result in lateral condyle osteonecrosis (may also occur in the trochlea)
Fishtail deformity
- area between medial ossification center and lateral condyle ossification center resorbs or fails to develop
- does NOT predispose to arthritis
- treatment
  - supracondylar osteotomy
Lateral overgrowth/prominence (spurring)
- incidence
  - up to 50% regardless of treatment, families should be counseled in advance
- risk factors
  - result of displacement of the metaphyseal fragment in addition to disruption of the periosteal envelope
  - lateral periosteal realignment will prevent this from occurring
  - spurring is correlated with greater initial fracture displacement
Growth arrest
- incidence
  - rare complication
- risk factors
  - varus or valgus deformity
- treatment
  - young patients may be treated with bar resection or osteotomy
  - older patients best treated with completion of the epiphysiodesis and osteotomy
Unsatisfactory appearance of surgical scar