Background

In 1883, Stimson first described the fracture patterns in lateral condyle fractures in his book Treatise on Fractures.[1] He described the fracture as beginning in the lateral metaphysis proximal to the condyle, coursing distally, and exiting through the articular surface through the medial trochlear notch or through the capitellotrochlear groove. In 1955, Milch recognized the significance of these fracture patterns as they related to elbow stability.[2] Thus, the fracture patterns of the lateral condyle bear his name and are classified as either Milch I or Milch II fractures.[3, 4, 5]

Problem

The distal humerus is primarily cartilage at the age when these injuries typically occur, and knowledge of the secondary centers of ossification is necessary to understand the possible fracture patterns. Due to incomplete ossification, the fracture may appear subtle on radiographs as it courses through the cartilage anlage, as depicted in the images below.

Normal contralateral elbow.

Note the subtle fracture line.The physis of the lateral condyle extends into the trochlear notch of the distal humerus (see image below). Therefore, in some fractures, the lateral crista of the trochlea may be part of the fracture fragment, leading to an unstable humeral ulnar articulation.

Diagram of intact distal humerus.The difficulties related to treatment of this fracture are both biologic and technical. Biologic problems are a result of the healing process and may occur with appropriate treatment and anatomic reduction. These problems include lateral spur formation with pseudo cubitus varus and true cubitus varus. Technical difficulties are the result of errors in management and may result in nonunion, malunion, valgus angulation, avascular necrosis, or a combination of these conditions.

One study found the current clinical imaging modality, radiography, may have a reduced sensitivity and inability to detect true displacement (see Imaging Studies).[6] The reduced precision of the radiographs may affect fracture management. For example, a patient who requires surgery (as indicated) may be treated with immobilization due to failure of the radiograph to illustrate the true fracture displacement (see Complications). A high clinical suspicion of a displaced fracture may require further diagnostic studies, possibly using MRI or arthrography (see Indications).

Epidemiology

Frequency

Lateral condyle fractures, as depicted in the image below, account for 17% of all distal humerus fractures and 54% of distal humeral physeal fractures. The frequency of lateral condyle fractures peaks in children aged 6 years. Most fractures occur in children aged 5-10 years. Cases have been reported in patients as young as 2 years and as old as 14 years.

Lateral condyle fracture, additional view. The fracture may be subtle and can sometimes be missed.

Etiology

Two theories of the mechanism of injury for this fracture exist. The first is the pull-off theory, in which avulsion of the lateral condyle occurs at the origin of the extensor/supinator musculature. This may occur as a varus stress is applied to the extended elbow with the forearm supinated. This is thought to be the most common mechanism of injury. The second is the push-off theory, in which a fall onto the extended hand leads to impaction of the radial head into the lateral condyle, causing the fracture.[7]

PreviousPathophysiology

The lateral condyle fracture is a Salter-Harris IV fracture pattern and follows physeal injury principles. For more information about injuries of the growth plate, see Salter-Harris Fractures. The fracture fragments in these patients are primarily cartilaginous as a result of the young age of the patients. The radiographic interpretation may be misleading because the visible fragment appears smaller than the actual size and, in addition, the amount of displacement is not appreciated.

In lateral condyle fractures, the displacement is greater than appreciated, and incongruity of the articular surface is present. Fractures with minimal displacement must be carefully monitored, as they have a high tendency to displace. Once these displaced fractures consolidate in a malunited position, treatment is difficult, dangerous, and fraught with complications. For these reasons, surgical reduction should be performed and is recommended within the first 48 hours postfracture.

Presentation

Children usually present with a history of a fall onto an extended arm. Patients present with pain and associated elbow swelling. Physical examination demonstrates a swollen elbow, pain greatest over the lateral condyle, and refusal of the patient to actively move the elbow. Occasionally, crepitus is present in an unstable fracture pattern. Significant deformity may indicate an elbow dislocation.

Indications

Operative management is essential for all displaced fractures and in those demonstrating joint instability or the potential for delayed joint instability.

Stage I, or type I, lateral condyle fractures with less than 2 mm of displacement may be treated with immobilization. If there is a question of stability or the possibility of delayed displacement in these type I fractures, percutaneous pinning is recommended. If the degree of fracture displacement is questioned, anatomic reduction and surgical stabilization is needed. Open reduction is indicated for all displaced type II and type III fractures.

Contraindications

Fractures that are not greatly displaced and are identified on a delayed basis greater than 3 weeks should not undergo surgical intervention. Healing has progressed to a point that extensive dissection would be required to achieve reduction leading to a high incidence of avascular necrosis of the lateral condyle.

Lateral Condyle Fracture - PediatricAuthor: Evan Watts

Topic updated on 05/09/15 9:18pm

Introduction

Fractures involving the lateral condyle of the humerus Epidemiology

o incidence 17% of all distal humerus fractures in the pediatric

populationo demographics

typically occurs in patients aged 5-10 years oldo location

most commonly are Salter-Harris IV fracture patterns of the lateral condyle

Pathophysiologyo 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

Prognosiso outcomes have historically been worse than supracondylar fractures

articular nature, missed diagnosis, and higher risk of malunion/nonunion

ClassificationMilch Classification

Type I Fracture line is lateral to trochlear groove  

Type II Fracture line into trochlear groove  

Fracture Displacement Classification

Type 1 <2mm, indicating intact cartilaginous hinge

Type 2 2-4mm, displaced joint surface

Type 3 >4mm, joint displaced and rotatedPresentation History

o fall onto an outstetched hand Symptoms

o lateral elbow paino mild swelling

Physical examo inspection

exam may lack the obvious deformity often seen with supracondylar fractures swelling and tenderness are usually limited to the lateral side

o motion may have increased pain with resisted wrist extension/flexion may feel crepitus at the fracture site

Imaging Radiographs

o recommended views AP, lateral, and oblique views of elbow

internal oblique view most accurately shows maximum displacement and fracture pattern 

o optional views contralateral elbow for comparison when ossification is not yet complete routine elbow stress views are not recommended due to risk of fracture displacement

o findings fracture fragment most often lies posterolateral which is best seen on internal oblique views

CT scano indication

improved ability to assess the fracture pattern in all planeso findings

CT has limited ability to evaluate the integrity of articular cartilage may require sedation to perform the test

MRIo indication

provides the ability to assess the cartilaginous integrity of the trochleao findings

increased expense may require sedation to perform the test

Differential

Pediatric Elbow Injury FrequencyFracture Type % elbow injuries Peak Age Requires OR

Supracondylar fractures 41% 7 majorityRadial Head subluxation 28% 3 rareLateral condylar physeal fractures 11% 6 majorityMedial epicondylar apophyseal fracture 8% 11 minorityRadial Head and Neck fractures 5% 10 minorityElbow dislocations 5% 13 rare

Medial condylar physeal fractures 1% 10 rareTreatment Nonoperative

o long arm casting indications

only indicated if < 2 mm of displacement, which indicates the cartilaginous hinge is most likely intact

sub-acute presentation (>4 weeks) technique

cast with elbow at 90 degrees and forearm supination weekly follow up radiographs out of cast may be useful total length of casting is 3-7 weeks

Operativeo CRPP

indications some authors suggest CRPP for all lateral condylar fractures

with < 2 mm of displacement ability to maintain fracture fragment in a position to prevent

late displacement technique

closed reduction performed by providing a varus elbow force and pushing the fragment anteromedial

divergent pin configuration most stable third pin may be used in transverse plane to prevent fragment

derotation arthrogram can confirm joint congruity

o open reduction and fixation indications

if > 2mm of displacement any joint incongruity  fracture non-union

technique direct lateral approach avoid dissection of posterior aspect of lateral condyle (source

of vascularization)  percutaneous or subcutaneous pins may be used for fixation single screw may also be used with non-unions +/- bone

grafting  AVN

o posterior dissection can result in lateral condyle osteonecrosiso may also occur in the trochlea

Nonunion/maluniono caused from delay in diagnosis and improper treatment

o may result in cubitus valgus and tardy ulnar nerve palsy      Tardy ulnar nerve palsy

o slow, progressive paralysis of the ulnar nerve

o caused by stretching of the nerve, as is seen with cubitus valguso usually late finding, presenting many years after initial fracture

Lateral overgrowth/prominence (spurring)     o in up to 50% of cases regardless of treatment, families should be counseled in

advanceo lateral periosteal alignment will prevent this from occurringo presence of spurring is correlated with greater initial fracture displacement

Growth arrest with or without angular deformity Unsatisfactory appearance of surgical scar Late elbow presentation or deformity

o cubitus varus deformity is most common in nondisplaced and minimally displaced fractures

o cubital valgus less common, but more likely with significant deformities that cause physeal arrest 

o controversy whether to treat subacute fractures (week 3-12) nonoperatively or surgically

o most deformities can be corrected after skeletal maturation with a supracondylar osteotomy