Trauma About the Elbow II: Other Fractures

John M. (Jack) Flynn, MD

Jeffrey R. Sawyer, MD¹

Guru:

Lateral Condylar Fractures

Fractures of the lateral condyle of the distal humerus are the second most common fracture about the elbow in children after supracondylar fractures, and have a well-earned reputation for trouble: nonunion, malunion, cubitus varus, and persistent loss of motion. Fortunately, these problems usually are avoidable if the fracture is recognized in a timely fashion and treated with sound principles. To stay out of trouble, remember that in most cases, this is a torn-off block of cartilage with a bit of bone inside, so healing is slower than a metaphyseal fracture (like a supracondylar), articular congruity must be assured, and thoughtful fixation is even more important when dealing with a ball of cartilage. Soft tissue injury (torn/punctured muscle) is typically less severe than with supracondylar fractures, and acute associated neurovascular injury is rare.

DIAGNOSIS

Lateral condylar fractures are sometimes missed, or the fracture displacement is underestimated, on standard AP and lateral radiographs of the elbow (particularly by urgent care center doctors, who apparently are supposed to know everything about everything; Fig. 7-1). Because the plane of a lateral condylar fracture is oblique from anterior lateral to posterior medial, an internal oblique view of the elbow is usually best to show the largest amount of displacement (Fig. 7-2). Sometimes the metaphyseal fragment is such a thin sliver of bone that the fracture is missed completely. Another pitfall in diagnosis is confusing a less common Salter II fracture of the distal humerus with a lateral condylar fracture.
The radiographic appearance of a Salter II fracture with a lateral metaphyseal fragment may be similar to that of a lateral condylar fracture before ossification of the trochlea (see Fig. 6-6 in Chapter 6). Physical examination can be helpful. With a lateral condylar fracture, swelling and tenderness are predominantly on the lateral side of the elbow, while a Salter II fracture has more swelling medially, where the periosteum is torn, and not laterally, where the periosteum is intact. In addition, tenderness is more diffuse with a Salter II fracture.

Figure 7-1 Urgent care center does struggle diagnosing pediatric elbow fractures.

Figure 7-2 A: AP view of a lateral condyle fracture demonstrating less than 2 mm displacement. B: Lateral view of a lateral condyle fracture demonstrating less than 2 mm of displacement. C: Oblique view, looking at the lateral side of the elbow tangentially, showing greater than 2 mm of displacement. Without this radiograph, one may have assumed there was less than 2 mm of displacement, and treated the fracture nonoperatively.

TREATMENT

Some wisdom in treating a lateral condylar fracture can be gained by considering the biomechanics. These fractures resemble a tearing injury: the child lands from a fall and instead of the elbow hyperextending (supracondylar fracture), a high-energy varus force is applied. The lateral metaphyseal bone and cartilage “tear.” Sometimes this tear stops in the midline cartilage (Fig. 7-3A), and sometimes it propagates into the joint (Fig. 7-3B). With still more force, it can tear the entire lateral piece off and spin it around (Fig. 7-3C). Rarely, there can even be an associated elbow dislocation. If the amount of maximal fracture displacement on all radiographs is 2 mm or less, and the fracture line does not extend through the trochlear cartilage, cast immobilization for 6 weeks will be successful. To stay out of trouble, pay special attention to fractures extending into the epiphysis: if initial displacement is less than 2 mm, apply a cast but image the fracture weekly for 3 weeks to be certain displacement has not occurred. To allow better radiographic visualization of the fracture, fiberglass rather than plaster casting is helpful, but do not hesitate to remove the cast to get good quality radiographs. NEWSFLASH! If a minimally displaced lateral condylar fracture is so unstable that you are concerned about removing the cast for a good X-ray, it probably should be pinned.

Stay out of trouble by treating fractures with more than 2 mm of displacement with operative reduction and internal fixation. If a medial hinge is in question, an arthrogram can help. NEWSFLASH! Arthrograms of pediatric elbow fractures should be done by injecting the dye into the olecranon fossa, not the fracture
site (Fig. 7-4). Fractures with a medial hinge and more than 2 mm of displacement often can be reduced closed, then pinned in place successfully. Reduction is achieved with the elbow in extension and a valgus force applied, but holding that position and force while pinning can be frustrating, even with the best assistant. To decrease your frustration and increase your pinning joy, put towel roll under the distal humerus. If the articular surface is displaced, open the fracture site and get a perfect articular reduction.

Figure 7-3 A: A lateral condyle fracture may be completely through the ossified portion of the distal metaphysis, but not enter into the joint. This fracture pattern presumably occurs because of the flexible nature of the cartilaginous epiphysis. B: Other times, the fracture crosses the joint. C: With enough force, the entire lateral piece can be broken off and spun around.

THE GURU SAYS…

Follow the traumatic rent whenever possible. The proximal dissection usually is done by the fracture itself. Use the radial head as your limit for distal exposure and the posterior interosseous nerve will be protected. With widely displaced fractures, the distal fragment may be so rotated that it is difficult and a little disorienting at first to determine how to reduce it. Remember that the articular surface may be just under the capsular incision and is at risk for iatrogenic injury. Use the concave surface of the capitellum to orient yourself.

JEFFREY R. SAWYER

In little elbows, the distance from the fracture to the posterior interosseous nerve and brachial artery is short.

Fortunately, once you’ve dissected through superficial fascia, a traumatic rent in the wrist extensor muscle mass is usually present, which gets you to the fracture site with very little sharp dissection below the skin. This opening may be enlarged
to visualize the fracture site and remove hematoma. To minimize the chances of osteonecrosis, soft tissue attachments on the posterior portion of the fracture fragment should not be detached, as the only blood supply to the lateral trochlea and capitellum enter in the posterior nonarticular portion.

Figure 7-4 A: Lateral view of elbow with fluoroscopy in which an arthrogram is being performed by placing a needle into the olecranon fossa from a posterior approach. B: Anterior-posterior view of an arthrogram of the same elbow. This demonstrates that the articular surface is intact, so the fracture does not extend into the joint. Most frequently, closed pinning is sufficient when the articular surface is intact.

Anatomic reduction of the articular surface is performed and verified under direct visualization (a headlight can be helpful). If reduction is challenging, try some dorsiflexion of the wrist to relax the wrist extensors attached to the distal fragment. Two smooth pins are placed percutaneously (just posterior to the incision) in a divergent trajectory—the same one you would use for divergent pinning of a supracondylar fracture. To stay out of trouble, avoid a lower pin that is parallel to the joint, and usually only in cartilage (cartilage doesn’t pin well, does it?) and the wrong trajectory for the fracture plane (Fig. 7-5). ORTHOPAEDICS 101: Fixation is best when it is perpendicular to the plane of the fracture.

Unlike supracondylar fractures, which nearly always heal in 3 weeks, lateral condylar fractures should be casted with the pins in for 4 weeks, then remove the cast, image, remove the pins, and then cast for an additional 2 weeks. With all that cartilage, give a lateral condyle a solid 6 weeks of cast protection. A potential complication with these intra-articular pins is pin site infection with a subsequent septic elbow, so carefully weigh the benefits versus risks of leaving pins in longer than 4 weeks, and certainly examine the pin sites if you choose to leave the pins in longer.

Despite the usual excellent results with reduction and pin fixation, some have experimented with using a screw to hold the fragment in place. This is a path to unnecessary trouble, especially in young children (<8 years of age), who usually get great results with simple pin fixation. In young children, the fracture fragment is mostly cartilage, and it is small. So, some try a single screw to compress this cartilage fragment in place. As you might expect, the cartilage fragment rotates on that single screw axis, creating a malunion machine. In addition, screw fixation should not be through the olecranon fossa (a joint is a bad place for threads), so it must be up the lateral column, which demands a trajectory starting on the lateral edge of the fragment (not much bone there). Screw fixation is valuable in delayed unions and malunions and in older children (>10 years of age) with very large bone fragments. Otherwise, the pediatric fracture surgeon is actually looking for
trouble when they abandon the successful divergent pin strategy for a fresh fracture in young children.

Figure 7-5 A: Anteroposterior radiograph demonstrating the horizontal pin failing to engage ossific bone in the proximal to the fracture. B: Ten weeks after surgery, the patient has elbow pain and stiffness, and the radiograph demonstrates a lack of union. C: Rigid fixation with a compression screw was used at time of second surgery to allow early motion. Screw should be only in the lateral column and not in the olecranon fossa or terminal elbow extension would be compromised. D: The ideal pin configuration for a lateral condyle fracture. Both pins are perpendicular to the plane of the fracture, and both engage to far cortex. The lower pin has four cortices thanks to the olecranon fossa. The fracture is perfectly reduced. These pins were pulled in the office at 4 weeks, and then the fracture was casted for 2 additional weeks with a perfect result. A screw cannot do better than this and would be removed with a second anesthetic.

LATE PRESENTATION

Traditional teaching suggests that open reduction should not be performed in fractures seen later than 3 weeks, as the risk of poor results from stiffness and osteonecrosis increases. However, if one carefully avoids posterior dissection to maintain blood supply of the distal fragment, good results with open reduction of lateral condylar fractures can be achieved.

A key approach to avoiding trouble in the treatment of late lateral condylar fractures is to not necessarily aim for anatomic reduction; it is preferable to fix it where it lies with no posterior stripping. This technique has been described as “metaphyseal osteosynthesis in situ” in the past. These fractures are similar to a slipped capital femoral epiphysis in that respect. Consider rigid fixation with a screws or screws in compression in late cases to maximize healing and early ROM, while remembering to avoid the olecranon fossa.

OTHER TROUBLE

Lateral condylar fractures heal more slowly than other fractures the pediatric orthopaedist is accustomed to treating. Be patient. It can be 10 or even 12 weeks before solid union. Look on the lateral radiograph for the first signs of healing—a wisp of periosteal new bone from fragment to metaphysis is a great sign that healing is under way. Lateral overgrowth from new bone can give the appearance of cubitus varus—but it is not. Warn parents ahead of time that they may see a lateral prominence when the cast comes off and the arm is atrophied. In some cases, lateral overgrowth is clear (Fig. 7-6). Either way, assure parents it is rarely severe enough to require treatment. Posterior osseous spurs may occur with both operative and nonoperative treatment. These seldom cause any problem other than parental concern over the radiographs (Fig. 7-7). Persistent elbow stiffness is more common following lateral condylar fractures than supracondylar fractures; prepare the family, use physical therapy (PT) after healing, and set expectations that return to sports may be a few months after injury.

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