Lateral condyle fractures occur less commonly than supracondylar humerus fractures, in the range of 15% to 20% of pediatric elbow fractures. The fracture is usually secondary to a fall. There is some debate whether the radial head pushes off the lateral condyle or whether the extensor-supinator muscle mass pulls off the lateral condyle with valgus-extension stress.1–3 Either way, if the joint surface is displaced, it needs reduction and stabilization.
Clinical examination will reveal swelling, tenderness, and ecchymosis. Radiographs, especially oblique views, are necessary for diagnosis.4 Because the capitellum is the first of the secondary centers of ossification to appear, diagnosis is readily made by plain radiographs. Ultrasound, magnetic resonance imaging, and computed tomography scans are rarely needed except in rare circumstances. Most notably, computed tomography scans are indicated for capitellar shear fractures and magnetic resonance imaging scans for complex elbow fracture dislocations in the young.
The Milch classification is classic, defining a Milch I as a fracture through the secondary center of the capitellum and a Milch II as a fracture through the ulnar-trochlear groove of the distal humerus. Mirsky et al5 defined a third type as extending medially and exiting through the physis.
Most surgeons use the Jakob classification,6 as it defines articular displacement and therefore surgical indications. A Jakob I fracture is nondisplaced (<2 mm), II is displaced >2 mm but not malrotated, and III is completely displaced and malrotated.
INDICATIONS FOR NONOPERATIVE TREATMENT
Stable, Jakob type I (<2-mm displacement) fractures have been treated successfully with a cast, splint, or collar and cuff.6,7
Aside from immobilizing the elbow in acceptable flexion consistent with the amount of swelling, placing the forearm in supination and the wrist in extension may lessen the risk of displacement. Because the lateral condyle is the origin of the supinator-extensor muscle mass, positioning the arm this way will decrease the risk that the muscles will “pull off” the lateral condyle resulting in an unacceptable articular alignment. Any patient treated nonoperatively should be followed closely with radiographs (every 7 to 10 d), including oblique views. If the clinician is uncertain about anatomic alignment, gentle out of immobilization radiographs are prudent to be certain that there is no significant articular displacement. The fracture will heal in 3 to 6 weeks.
INDICATIONS FOR OPERATIVE TREATMENT
All type II and III displaced fractures need anatomic reduction and internal fixation. Articular and physeal malalignment requires restoration to preinjury anatomic positioning. Stabilization is necessary to prevent displacement after reduction. Arthrograms may be helpful to confirm anatomic articular congruity.
Closed reduction and percutaneous pinning (CRPP) or open reduction internal fixation (ORIF) are both commonly used in displaced lateral condylar humerus fractures. Closed reduction can be performed with varus stress at the elbow with the forearm supinated. Once anatomically aligned, the fracture is pinned with smooth pins. Two or 3 divergent pins that penetrate the far cortex, similar to supracondylar humerus pinning techniques, are used. At times, a pin parallel to the joint is used due to the obliquity of the fracture for more stability. If there is difficulty obtaining the reduction with closed manipulation, the percutaneous pins can be used to joystick the fracture into place before driving them across the fracture site for stabilization. If the articular congruity is in doubt, an arthrogram is performed using a 1:1 mixture of saline and arthrographic dye injected into the joint from either the lateral “soft spot” or from posteriorly just proximal to the olecranon tip. Anatomic alignment of the joint is mandatory.8,9 Arthroscopic-assisted reduction and stabilization has been described as well.
If the metaphyseal fragment is large enough, a percutaneous cannulated compression screw can be used.9 The lateral condyle will only tolerate 1 screw. A second smooth wire may be used to prevent malrotation with screw tightening. A washer can be used to broaden the forces across the lateral condyle. The screw can be placed in the metaphysis or by some surgeons across the physis. Growth arrest is of concern but does not seem to be a problem by limited reports.
Finally, ORIF is performed for malrotated and malaligned fractures that are not reducible by closed means. Surgical exposure is through a direct lateral approach. There will be marked disruption of the soft tissues. After skin incision, gentle spreading with a blunt instrument or finger will lead to joint exposure. Debridement of hematoma is performed with irrigation and suction. The fracture fragment is usually large and often has to be untwisted. Preservation of the posterolateral soft tissue attachments to the lateral condyle is necessary to lessen the risk of avascular necrosis. Dissection anteriorly may be required to directly visualize the fracture and its anatomic reduction. After restoration of articular congruity, the fracture is stabilized with 2 or 3 smooth pins or a single compression screw. At times, reduction requires use of skin hooks, a modified dinner fork, or pins as joysticks. After fracture fixation, direct visualization of the anatomic joint surface is performed to confirm reduction, and the elbow is taken through a full arc of flexion-extension motion. Repair of the soft tissues is performed with wound closure. It is imperative to be certain that there is anatomic alignment before completion of the surgery. The pins are left exposed, as this lessens the risk of pin infections and removed in the office with radiographic evidence fracture healing, usually at 4 to 6 weeks. If a screw is used, it is left buried and removed at 6 months.
The degree of displacement and fracture instability that can be treated with CRPP is still unclear. More aggressive CRPP with unstable type III fractures risks a malunion. More frequent ORIF may be unnecessary in more stable, less displaced fractures and increases the risk of avascular necrosis by extensive soft tissue dissection. In the end, what matters is an anatomic, stable joint surface.
The first case illustrates the necessity of obtaining oblique radiographs in addition to the standard anteroposterior (AP) and lateral views taken to assess elbow fractures. The AP and lateral x-rays in this particular case show a Jakob type I nondisplaced lateral condyle fracture (Fig. 1), but the internal oblique view shows >5 mm of displacement (Fig. 2). Song et al10 found a 70% discrepancy in the measurement of displacement of lateral condyle fractures on AP and internal oblique imaging. Thus, when considering nonoperative treatment of a nondisplaced lateral condyle fracture, the surgeon must fully assess the fracture radiographically with AP, lateral, and oblique radiographs in order to be confident that it is truly nondisplaced. In addition, the fracture should be imaged during nonoperative treatment to monitor for later displacement.
After seeing the internal oblique view, all panelists agreed that operative treatment was indicated for this case. An intraoperative arthrogram is the best means of assessing the articular surface. The arthrogram may be performed by injecting contrast through the lateral elbow soft spot bounded by the lateral epicondyle, the radial head, and the olecranon or through a posterior approach that injects the contrast into the olecranon fossa. The olecranon fossa approach has the advantage that misplacement of contrast into the surrounding soft tissues does not obscure visualization of the lateral joint that may occur if the soft spot approach is used. Another tip for ensuring that your contrast injection is in the joint is to place the needle first and inject saline. If the saline can be withdrawn, the needle is in the joint and contrast can then be injected. If not, the needle should be repositioned.
The amount of displacement of the articular surface on intraoperative arthrogram may help to determine whether closed or open reduction of a lateral condyle fracture is indicated. Pin or screw fixation may be used with emphasis placed on divergence and bicortical fixation. One pin or screw is often directed transversely across the fracture and parallel to the elbow’s articular surface (Figs. 3A, B).
The second case is a Jakob type II lateral condyle fracture with >2 mm of displacement (Fig. 4A). All panelists agreed that this fracture should be managed operatively in order to avoid complications of nonunion and articular incongruity. An intraoperative arthrogram was again recommended for this case. Closed or open reduction with pin or screw fixation should be performed (Fig. 4B). Whether performed by open or closed means, reduction should be assessed by the fracture’s congruity at the articular surface and not at the metaphysis. With open treatment, dissection should be focused anteriorly and laterally in order to avoid the blood supply to the trochlea posteriorly.
Healing of lateral condyle fractures is slower than with supracondylar humerus fractures and requires a longer period of fixation and/or immobilization. Pins usually are not buried but often must be kept in place until the fracture is healed, often up to 6 weeks.
The third case is a Jakob type III lateral condyle fracture with significant displacement (Figs. 5A, B). Although most panelists suggested open reduction, K.S.S presented his series of similarly displaced lateral condyle fractures that were treated with CRPP using a joystick technique. In his series, he was able to teach 3 other orthopaedists to perform his technique, and they were also able to perform closed reduction and pinning successfully in 75% of patients. There are many surgeons who still treat the type III fracture with ORIF.
The major concerns of a lateral condylar humerus fracture are malunion and/or nonunion. Articular malunion will result in pain and eventually potentially arthrosis. Depending on the degree of malunion, this can be debrided open or arthroscopically or treated with a complex intra-articular osteotomy.
Nonunion is due to failure of recognition and fixation of the fracture fragment. An incipient nonunion can be treated with operative fixation with healing. An established nonunion may require a several stage reconstruction with in situ fixation and grafting, ulnar nerve decompression, and corrective osteotomy.
Lateral spur formation is expected. Slight cubitus valgus or varus are not uncommon and often do not require corrective osteotomy.
SUMMARY OF 3 MOST IMPORTANT POINTS
- Watch all lateral condylar fractures that are treated nonoperatively very closely, especially with oblique radiographs.
- Restore anatomic alignment of the distal humerus articular surface in all displaced lateral condylar humerus fractures.
- Stabilize all displaced fractures until they are healed radiographically.
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Keywords:© 2012 Lippincott Williams & Wilkins, Inc.
lateral condyle; distal humerus; open reduction; closed reduction; percutaneous pinning; elbow arthrogram