Bedside ultrasound has the potential to dramatically speed up the diagnosis and treatment of classic FOOSH injuries in children.
“What I did was save us a whole lot of time. The patient is a 4-year-old who tripped and extended her arm to break her fall—a classic axial-load ‘FOOSH’ injury. She affirmed point tenderness near her distal radius but with zero visible angulation. She denied any pain or tenderness of her distal radial epiphysis, carpal bones, proximal radius, distal ulna, ulnar styloid, ulnar shaft or elbow.
Her motor, sensory and vascular exams were normal, and she was able to supinate and pronate without discomfort, making a more complicated injury extremely unlikely. X-ray was really backed up, so I did a bedside ultrasound, which demonstrated a very subtle buckle fracture of the distal radius at the site of her maximal point tenderness (Figure 1).
I doubt that I would have been able to see this fracture on plain film. I had my medical student run copies of the printed images over to orthopedics who agreed to see them in their clinic at the end of this week. I archived multiple images and they will be able to access them at the time of follow-up.
“Did you think to…” “Ultrasound her elbow? Yes, and it was normal.”
“Did you…” “Place her in removable splint? Yes.”
“How long did the entire process take?” “About 3 minutes.”
“Are you sure there was no angulation?” “Yes. Here are the images. But even if there was slight angulation – less than 10 degrees – we would not have reduced it in a child this young. Had that been the case, I would have placed a more secure sugar-tong splint with the same directions for orthopedic follow-up.”
“Hmm…I suppose it’s better to hope for forgiveness than to ask for permission. Especially when you saved at least an hour. Maybe we can learn from this. Good work.”
We never cease to be amazed by emergency medicine resident creativity in response to the virtually unlimited variety of challenges they face. Indeed, such “in-the-moment” survival maneuvers often become tomorrow’s “disruptive innovations” that improve institutional efficiency and effectiveness of care.
The development of musculoskeletal ultrasound by emergency physicians has, indeed, been a game changer. The maneuverability of ultrasound allows for multiple focused assessments, synergy of physical and sonography assessment, and the detection of subtle injuries that may escape conventional plain radiography.
Low-risk injuries, such as the one described in the above case vignette, may not warrant a lengthy wait in the X-ray queue. The use of ultrasound in this situation not only expedited patient disposition but also facilitated immobilization and protection via the use of rapidly-applied commercial splint.
KEY TEACHING POINTS
Distal forearm fractures are extremely common in children, comprising 40 to 50% of all pediatric fractures. Toddlers fall frequently, and their bones are soft and pliable. In contrast to adults, pediatric distal radius fractures are predominantly extra-articular.
There is occasional confusion regarding appropriate terminology for the various subtypes of distal forearm fractures. Buckle fractures, also referred to as Torus fractures, occur when the forearm is subject to a compressive force due to axial loading (Figure 2), typically as a result of a fall onto an outstretched hand (FOOSH).
These fractures do not extend through the bony cortex, may be difficult to detect using conventional radiography, and normally heal without deformity following two to three weeks of restricted activity. The use of removable splints has become increasingly popularas it hastens the return of full function and is considerably more tolerable than are casts or splints that are not easily removed.
Colles fractures also result from a FOOSH mechanism but with a somewhat more oblique force vector that causes the characteristic “apex-volar, dorsal-angulation-of-the-distal-fragment” configuration. Colles
fractures are more likely than Buckle/Torus fractures to displace if not securely immobilized and, therefore, a more traditional splint or a cast is utilized.
In comparison to conventional skeletal radiography, ultrasound is considerably faster, far more convenient, allows for real-time evaluation at the bedside, can be focused at the point of maximal tenderness, and can utilize numerous imaging planes to increase sensitivity for the detection of cortical disruption.
In a busy emergency department, ultrasound can be performed immediately upon arrival (in triage) and is able to identify injuries that will require reduction as well as those that will be appropriately treated with splinting and discharge.
A careful physical examination should precede ultrasound in an attempt to focus subsequent sonographic interrogation. Most children are more than capable of communicating the precise point of maximal bony tenderness and will “narrow” the sonographer’s search. Very little physician-applied fingertip pressure is necessary for identification of the fracture site.
A high-frequency linear transducer provides excellent resolution for the identification of cortical irregularities. The operator should first identify the highly-echogenic cortical line in a non-tender area near the suspected fracture site and then follow the cortex toward the site of maximal point tenderness.
Disruption of the cortical line is most easily appreciated in the presence of buckling and angulation but can also be identified in fractures that are displaced. Sonographic interrogation for a possible fracture should occur orthogonally; along both the coronal and sagittal planes of the forearm. Many sonographers will actually scan along the length of the dorsal, lateral and volar radius in an attempt to avoid missing a subtle fracture appreciable in only one cortical area. A hypoechoic effusion immediately adjacent to the fracture site will often be noted.
The combination of point-of-care sonographic diagnosis and the timely application of a pre-packaged commercial splint can markedly expedite emergency department diagnosis and treatment of forearm buckle fractures. The use of a removable splint for the immobilization of radial buckle fractures has been demonstrated to be safe and to hasten recovery of function.
Salter-Harris fractures of the distal radial growth plate are noted in older elementary school-age children and may involve movement (“sliding”) of the epiphysis relative to the metaphysis. Patient tenderness to palpation occurs in a more distal location as opposed to buckle and Colles fractures.
Although long bone fractures may be well-visualized by those with limited ultrasound instruction and experience, sonographic assessment in and around joints and growth plates is considerably more challenging and requires greater operator skill and knowledge of ultrasound anatomy.