Supracondylar humerus fracture is a common injury in children, and it generally heals uneventfully under appropriate orthopaedic management. Still, serious complications may arise, most notably compartment syndrome and nerve injury—with permanent consequences if they are not anticipated or recognized and managed promptly.

At an AAOS 2018 Annual Meeting symposium, a panel addressed “Staying Out of Trouble in Pediatric Trauma,” offering guidance on managing various fractures in children. David L. Skaggs, MD, gave tips for avoiding common pitfalls in the handling of supracondylar fractures of the humerus.

Dr. Skaggs, chief of orthopaedic surgery at Children’s Hospital Los Angeles, said a basic pitfall is not recognizing the urgency of some situations at initial presentation. During examination, the extremity should be assessed for pulse and perfusion, he advised. About 2 percent to 3 percent of injuries will be pulseless. Although gentle traction and flexion often return pulse, a hand that remains pulseless should be assessed for color; warmth; and arterial capillary return, which should be less than two seconds. If a pulseless hand is pink and warm, the case is “urgent that night,” Dr. Skaggs said. If the hand is pale and cold, the case should be considered an emergency and surgery should be done as soon as possible, without an arteriogram performed first, as 22 percent of such scenarios will involve compartment syndrome and 44 percent will necessitate vascular repair. “Fix it; don’t do more studies,” Dr. Skaggs said.

Puckering, ecchymosis, and ipsilateral forearm fracture are also urgent indicators, he said. “The residents all know—call the attending. You want to address it in the middle of the night. It’s not a next-day case.”

Images used with permission from Children’s Orthopaedic Center, Los Angeles.

Before and during treatment

Turning to nerve injuries, which occur in about one in seven supracondylar fracture cases, Dr. Skaggs said, “It’s very important that you conduct an examination preoperatively so that you know if a nerve is out before surgery. If you have a nerve out postoperatively, and you don’t know if it is out beforehand, that’s a tough situation. If there is a sensory nerve injury, we consider that an urgent case that should be done that night.” A sensory nerve injury may mask compartment syndrome, and it is also a sign of a higher-level-of-energy injury.

Regarding treatment pitfalls, Dr. Skaggs said a Baumann’s angle of 10 degrees or more should be appreciated in the anteroposterior view, and in the lateral view the anterior humeral line should cross the capitellum in the normal elbow. The clinician should “beware of medial comminution,” Dr. Skaggs said. “The injury may not look too bad, but if you have a medial comminution, and Baumann’s angle is less than 10 degrees, if it is not fixed, the child will develop permanent deformity of malunion/cubitus varus (Fig. 1) and may need a much more extensive osteotomy later. You have to fix those.”

Another pitfall Dr. Skaggs addressed is undertreatment of type II fractures. A course of closed reduction and casting can lead to loss of reduction and poor outcomes in 8 percent of cases, he said. “Many people think ‘kids are young; they remodel,’” he said, “but there is not a lot of remodeling about the elbow. Maybe that is the case in the very youngest kids, but generally, stay out of trouble and fix type II fractures. There have been papers written that say you could just treat a type II in a cast, but all those papers show a significant number of patients losing reduction. You can’t always get the patient back to the operating room before they heal in a bad position.”

Hyperflexing the elbow to reduce the type II fracture may lead to a decrease in Doppler pulse and an increase in compartment pressure, leading to compartment syndrome, Dr. Skaggs said. “To stay out of trouble, never maintain an elbow with a supracondylar fracture in a hyperflexed position. If it is a type II, pin it, and then you can extend the elbow and let the pins hold the reduction.”

Clinicians should be alert to “rubbery reduction,” Dr. Skaggs said. “In the reduction, you should get this wonderful feeling of bone crunching on bone as the fracture reduces. If you feel a rubbery or ‘bouncy’ sensation, as if there is a nerve in there, that is a bad sign, particularly if the median nerve was out to begin with. Consider opening the fracture and looking for the median nerve.”

Hardware considerations

Dr. Skaggs advised the use of three—possibly four—pins for a type III fracture. “Although bigger pins are stronger,” he said, he finds size 0.062 pins to be sufficient for almost every fracture. He advised surgeons to maximize the separation at the fracture site to at least one-third of the medial to lateral width of the fracture. “Chances are the fracture won’t fall apart,” he said, adding, “Don’t hesitate to use extra pins. Stress the site with live imaging—varus, valgus, flexion, and extension. If the fracture is going to fall apart, you want it to fall apart right there in front of you so you can fix it, rather than next week when the child falls down.”

Use of a medial pin may incur injury of the ulnar nerve, possibly leading to a permanent claw hand, Dr. Skaggs said. “I would say that 98 percent of supracondylar fractures do not require a medial pin. If it is an oblique fracture and you feel a medial pin is necessary, put in the lateral pins first, extend the elbow, allow the ulnar nerve to drop posteriorly, then place the medial pin.”

After pinning, Dr. Skaggs advises protecting the skin with sterile felt, although some surgeons may use petroleum jelly gauze. “Make sure those pins have a mechanical barrier from hitting the skin. Afterward, I like to use sterile foam directly on the skin; others like to use bivalve casts or splints,” he said. “You want to allow for postoperative swelling, and particularly in the really swollen fractures, do not cast with 90 degrees of elbow flexion, as the pins are holding the reduction. Cast at 40 degreess to 70 degrees of flexion, and make sure you feel the pulse in that position. Sometimes you can feel the pulse disappearing with flexion, and as you extend, the pulse comes back.”

Dr. Skaggs summarized the assessment and decision-making that occur after surgery on a pulseless supracondylar humeral fracture. “You fix it, and the pulse comes back, and the hand is warm and red—great day.” However, if the hand had been pulseless, he said, “you still might want to keep the child overnight for 24 hours if it was because of a high-energy injury.”

If the hand is white and poorly perfused after reduction, “you can’t leave the operating room [OR]. You have to fix it.” The site should be explored with an anterior incision, he said. “Most of the time, you are looking for soft tissue near the artery that is pulled into the fracture site. Freeing the artery from tethering soft tissue is often sufficient.” One should consider lidocaine to the artery and doing a compartment release if pulselessness has lasted six hours or longer.

The incision is a straight transverse line along the antecubital fossa. “It sounds scary to orthopaedic surgeons who are generally taught to avoid vascular structures,” Dr. Skaggs said. To demonstrate the anatomy, he instructed the audience: “Bend your elbow 90 degrees, feel your biceps tendon, and just medial to it, you can feel the lacertus fibrosus (bicipital aponeurosis). Following the incision, slide a clamp under the lacertus fibrosus, open it up, and there is your brachial artery and nerve on the medial side of the biceps tendon. If they are not there, go proximal into normal tissue to find them.”

After surgery

Postoperatively, if the hand is pulseless and well perfused, “you are probably OK,” Dr. Skaggs said. “There is rich collateral circulation, but keep the child in-hospital for 48 hours of observation. I’ve seen many occasions where in 24 to 36 hours it goes bad and you have to return to the OR. Generally, the artery is not in the fracture site but soft tissue is pulling the artery at an angle.”

Unlike in adults, the first signs of compartment syndrome in children could be increasing needs for analgesic, he noted.

In place of the “five Ps”—pain, pallor, paralysis, paresthesia, and pulselessness—which signal risk in adults, surgeons treating children should be mindful of the “three As”—anxiety, agitation, and analgesia requirement. “Any time the nurse calls you and tells you the child seems to be needing a little bit more morphine, seems a little more anxious, or has more pain, think of compartment syndrome,” Dr. Skaggs said. After surgery for a supracondylar humerus fracture, the child should have less pain.

Editor’s note: This article is the first of a three-part series on an AAOS 2018 Annual Meeting symposium on pediatric trauma. The second installment, featuring femoral shaft fractures, will be published in the August issue of AAOS Now.

Terry Stanton is senior science writer for AAOS Now. He can be reached at tstanton@aaos.org.