Lateral Humeral Condyle Fracture


Background

In 1883, Stimson first described the fracture patterns of lateral condyle fractures in his Treatise on Fractures. [1He described these fractures 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. [2For this reason, the fracture patterns of the lateral condyle bear his name and are typically classified as either Milch I or Milch II fractures (see Presentation). [345]

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 (AVN), or a combination of these conditions.

Anatomy

The physis of the lateral condyle extends into the trochlear notch of the distal humerus (see the image below). Therefore, in some lateral humeral condyle 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. Diagram of intact distal humerus.

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. Because of incomplete ossification, the fracture may appear subtle on radiographs as it courses through the cartilage anlage (see Workup).

Pathophysiology

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; 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 after the fracture. [6]

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]

Epidemiology

Lateral condyle fractures 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.

Prognosis

In a study of 181 pediatric lateral condyle fractures treated with open reduction and internal fixation (ORIF; mean follow-up, 38 weeks; mean age, 5 years), Silva et al compared patients treated within 7 days after injury (group 1; n = 133) with those treated 7-14 days after injury (group 2; n = 48) to identify any significant differences in outcome. [8They reported no iatrogenic nerve injuries or vascular complications in either group, and mean operating time was similar. At final follow-up, groups 1 and 2 were similar with respect to range of motion (ROM), complication rate (low in both), and percentage of satisfactory outcomes.

Silva et al also studied 191 pediatric lateral condyle fractures treated either with ORIF (group 1; n = 163) or closed reduction with percutaneous pinning (CRPP; group 2; n = 28) and followed for over 12 weeks. [9They found CRPP to be a viable alternative for treating these fractures in cases involving limited initial displacement (2-4 mm); cosmetic results were better, operating times were shorter, and the complication rate was not significantly increased.

A study by Pennock et al yielded similar results for CRPP vs ORIF in pediatric lateral condyle fractures with 2.1-5.0 mm of displacement.



History

Children with lateral humeral condyle fractures usually have a history of a fall onto an extended arm. They typically present with pain and associated elbow swelling. 

Physical Examination

Physical examination demonstrates a swollen elbow, pain that is 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.

Classification

In 1964, Milch described an anatomic classification system that divided lateral condyle fractures into the following two types on the basis of the location of the fracture line [411:

  • Type I (less common) - The fracture extends through the ossification center of the lateral condyle and exits at the radiocapitellar groove (see the first image below), producing a Salter-Harris type IV fracture pattern; the lateral crista of the trochlea remains intact and therefore has less tendency to dislocate laterally
  • Type II (more common) - The fracture extends across the physis and exits through the apex of the trochlea (see the second image below), producing a Salter-Harris type II or type IV fracture pattern; the lateral crista is in the fracture fragment, and the trochlea is no longer intact, rendering the elbow unstable
Milch type I fracture pattern. Milch type I fracture pattern.
Milch type II fracture pattern. Milch type II fracture pattern.

In 1975, Jakob described a classification system based on displacement of the fracture fragment, which divided these injuries into three stages as follows [12:

  • Stage I - The fracture is nondisplaced with an intact articular surface
  • Stage II - The fracture extends through the articular surface, and there is moderate rotational displacement
  • Stage III - There is complete displacement and capitellar rotation with elbow instability

Some authors believe that the Jakob classification system is more useful than the Milch system.



Radiography

Obtain standard anteroposterior (AP), lateral, and oblique radiographs in patients with a suggested elbow fracture (see the first and second images below). Obtain a comparison view of the contralateral (ie, uninjured) elbow as a control or template (see the third image below). This is especially helpful when ossification is not yet complete. [13]

Lateral condyle fracture. Note subtle fracture linLateral condyle fracture. Note subtle fracture line.
Lateral condyle fracture, additional view. FracturLateral condyle fracture, additional view. Fracture may be subtle and can sometimes be missed.
Normal contralateral elbow. Normal contralateral elbow.

Varus stress views have been recommended in questionable cases. However, these are painful to the patient and may displace a previously undisplaced fracture. Reserve stress views for the operating room, where they can be performed under fluoroscopy and can assist in the decision of open versus percutaneous treatment.

The accuracy of radiographic measurements in assessing displacement in lateral humeral condyle fractures has been questioned. Radiography may not be sensitive enough to detect displacement. Knusten et al reported a failure to detect displacement of 2 mm when the upper extremity is positioned for an internal oblique lateral radiograph. [14 They found that the true fracture displacement measurements were larger than radiographic displacement measurements, with differences ranging from 1.6 to 6 mm.

The reduced precision of radiography may affect fracture management. For example, a patient who requires surgery (as indicated) may be treated with immobilization if radiography fails to illustrate the true fracture displacement (see Treatment).

Patients with a high clinical suspicion of a displaced fracture may require further diagnostic studies (eg, magnetic resonance imaging [MRI] or arthrography).

Arthrography

Arthrography assesses the size of the cartilaginous fragment and the articular displacement and can help in decision making in difficult cases. However, this study is difficult to achieve without sedation and should be reserved for the operating room.

Magnetic Resonance Imaging

MRI may be used to determine the size and degree of displacement (see the images below). It has taken the place of preoperative arthrography in cases that are difficult to manage. Sedation may be required.

MRI demonstrating Milch type I fracture pattern. MRI demonstrating Milch type I fracture pattern.
MRI demonstrating Milch type II fracture pattern. MRI demonstrating Milch type II fracture pattern.

Approach Considerations

Operative management is essential for all patients with displaced fractures and for 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 are needed. Open reduction is indicated for all displaced type II and type III fractures.

With prompt and appropriate treatment and a satisfactory reduction, good results may be expected with full elbow range of motion (ROM).

Nonoperative Management

Stage I fractures with less than 2 mm of displacement may be treated with immobilization. Maintain cast immobilization for 3-4 weeks at 90° of flexion and forearm supination. Close follow-up is necessary because of the high incidence of late displacement and subsequent malunion. Obtain follow-up radiographs with the arm out of plaster for better fracture evaluation and assessment of possible displacement.

If any question remains regarding joint stability or the possibility of delayed displacement, perform closed pinning.

Fractures that are not greatly displaced and are identified after a delay longer than 3 weeks should not undergo surgical intervention. Healing has progressed to a point where extensive dissection would be required to achieve reduction, leading to a high incidence of avascular necrosis (AVN) of the lateral condyle. If fracture identification is delayed by 6 weeks or longer, continue closed treatment regardless of displacement.

Operative Management

Operative management is required in type I fractures that demonstrate delayed displacement or instability. Fragment stabilization is most frequently performed through percutaneous placement of two smooth Kirschner wires (K-wires). [1516Open reduction and fragment stabilization are required for all type II and III fracture patterns. [17]

In children, fixation of lateral condylar humeral fractures with either K-wires or screws gives satisfactory results. It should be noted that some studies have suggested that screw fixation has a slightly lower nonunion rate than K-wire fixation does. [18Prospective randomized trials with long-term follow-up are required to confirm this difference. 

Operative details

With operative treatment, an anatomic reduction should be achieved. An anterior approach is followed to avoid the posterior vascular pedicle to the fracture fragment. This is important for minimizing the risk of AVN of the fragment.There is some debate as to whether AVN occurs because of stripping of soft tissues from the lateral condyle fragment rather than because of the specific approach used; nonetheless, caution is warranted. [19   

Before performing an open reduction, make a preoperative plan.

Place the patient supine on the operating table; apply a tourniquet. Use a radiolucent hand table. Ensure C-arm availability. Mark the anatomic landmarks.

With the anterolateral approach, the incision is 1 cm anterior to the lateral superior condylar ridge. Identify the fracture tear through the brachioradialis (anterior), the extensor carpi radialis (posterior), or both. Irrigate the fracture, and remove any hematoma from the fracture site so as to facilitate reapproximation. Reduce the fracture.

Place the smooth K-wires percutaneously under fluoroscopic control (see the image below). The pins should engage the opposite cortex.

Intraoperative fluoroscopic radiograph of KirschneIntraoperative fluoroscopic radiograph of Kirschner-wire fixation of lateral condyle fracture.

Deflate the tourniquet, and achieve hemostasis. Suture the periosteal flap into place to prevent lateral spur formation and pseudo cubitus varus. Close the wound with absorbable suture. Bend the pins. Apply a long arm splint with the arm in supination.

Elevate the operated extremity above the heart level, and apply ice to the splint at the fracture site. A sling may be applied for support and comfort.

Arthroscopic approaches

Arthroscopic-assisted reduction with internal fixation offers direct visualization of the articular fragment, ensuring articular congruity, and percutaneous fixation avoids an extended dissection. This option provides a more biologic approach to treatment of this fracture. [20Cross-training in arthroscopic techniques and fracture management is necessary. [212223]

Complications

Complications of lateral condylar fracture management include the following:

  • Lateral condylar overgrowth or spur formation (30%)
  • Cubitus varus
  • Nonunion
  • Malunion
  • Valgus angulation
  • Ulnar nerve palsy
  • AVN

These complications are either biologic problems, arising from the healing process, or technical problems, arising from management errors. [24]

Biologic problems include lateral condylar overgrowth or spur, which is due to overgrowth of the avulsed periosteal flap from the proximal fragment. This spur may give the appearance of a cubitus varus (pseudovarus) and cause difficulty in patients with a small carrying angle. In general, it should not cause a cosmetic or functional problem. This overgrowth usually undergoes remodeling and disappears over time.

Cubitus varus occurs in approximately 42% of patients sustaining a lateral condylar fracture, regardless of treatment. The cause of cubitus varus is not clearly evident. However, it probably is due to lateral condylar physeal stimulation or to slight reduction incongruence. Deformities usually are mild, and surgical correction is not necessary.

Technical problems related to lateral condyle fracture treatment include delayed union, nonunion, and cubitus valgus. Delayed union of lateral condyle fractures usually occurs in patients treated nonsurgically. The elbow usually is not painful. The fragment usually is stable and undergoes uneventful union over time.

Nonunion is considered present if no healing is evident at 12 weeks following injury. This may be caused by the pull of the extensor musculature, inadequate fixation or stabilization (immobilization), and failure to recognize the fracture. When the fragment is nondisplaced and is diagnosed relatively early, treatment with a compression screw can be performed. If nonunion is well established, exploration and removal of the interposed fibrous tissue is recommended, followed by insertion of one or two compression screws. Perform bone grafting if significant fragment separation exists. Definitive treatment can safely be delayed until the patient becomes symptomatic or reaches skeletal maturity.

Occasionally, a fishtail deformity of the distal humerus is seen because of the loss of ossific contact between the capitellum and trochlea. This results in a gap or a deficiency of the lateral trochlear buttress. This deformity usually does not result in any significant dysfunction and is treated nonoperatively.

A cubitus valgus deformity may occur if there is nonunion or malunion of a lateral condyle fracture. The deformity rarely is caused by lateral condylar epiphysiodesis. In simple valgus malunion cases, a medial closing wedge osteotomy is performed. In cases of angular deformity and nonunion, treatment is complex and difficult. Address and stabilize the nonunion, and perform a medial closing wedge osteotomy to correct the angular malalignment. This may be performed simultaneously, or it may be staged sequentially. Care must be given to the amount of dissection performed so as to avoid AVN of the lateral fragment. [25]

AVN of the lateral fragment in lateral condylar fractures is iatrogenic and most often occurs in cases treated late or in nonunions and delayed unions. This complication is the result of aggressive dissection during open reduction.

Acute neurologic injuries are rare. Tardy ulnar nerve palsy occurs late in the treatment and follow-up of lateral condyle fractures and usually is due to cubitus valgus. The average time for presentation of ulnar nerve neuropathy is 22 years following the fracture. This ulnar neuropathy can be treated with ulnar nerve transposition, cubital tunnel release, or medial epicondylectomy.

Myositis ossificans may occur, albeit rarely.

Long-Term Monitoring

Follow-up care is performed at 7 days and includes anteroposterior (AP) and lateral radiographs, with the arm out of plaster, to assess maintenance of reduction. A long arm cast is applied in supination. The patient is then seen at 3-4 weeks postoperatively, and the K-wires are removed. Physical therapy is initiated, and gentle active ROM is begun. The patient is next seen at 6 weeks, and AP and lateral radiographs are obtained. Return to full activity is allowed once radiographic confirmation of healing has been obtained.