buckle vs greenstick fracture

buckle fracture versus greenstick fractures

introduction

With football and soccer season upon us, the incidence of pediatric forearm fractures will normally increase.  Sports medicine providers may need to evaluate FOOSH (fall on outstretched hand) injuries and should be comfortable with the differences between the adult forearm and the pediatric forearm.  The provider should also be aware of potential pitfalls and fractures that may require surgery. 

The pediatric skeletal anatomy has unique properties that lead to varied pathology to that of the adult skeleton. Two of the major differences include the presence of the physeal growth plate and a thicker periosteum with the softer underlying bone.[1] With soft, malleable bone, and a thick protective periosteal covering, minor injuries can result in a spectrum of deformities with or without a cortical break. In long bones, injuries without a cortical break either lead to plastic deformation through microfracture or to a ‘kink’ within the long bone, described as a ‘buckle’ or ‘torus’ fracture. 

greenstick fracture buckle fracture illustration

Image 1: Buckle fracture AP and lateral.  Adopted from [21].

The mechanism of injury for buckle fractures is usually axial loading of the meta-diaphyseal junction of skeletally immature long bones [2]. This transition point is susceptible to failure due to the different biomechanical characteristics of the two types of bone: developing woven bone of the metaphysis and tough lamellar bone of the diaphysis. When axial loads surpass the plastic deformation threshold, trabeculae fail and cause the cortex to bulge outwards at the apex of the compressive forces. Buckle fractures are usually specific to children because their bone has a lower ash content (less hydroxyapatite) and is more likely to absorb force and experience plastic deformation [2]. Additionally, children have a thick periosteal sleeve above the cortex that typically stays intact and prevents unrestrained fracture extension and complete bone failure.

These differ to greenstick fractures, in which the bone bends (rather than crushes) resulting in a complete break in one cortex and a bend on the opposite side (akin to snapping a fresh twig from a tree).

greenstick fracture buckle fracture illustration

Image 2.  Greenstick fracture AP and lateral.  Adopted from [21].

The appearance on plain X-ray for buckle fractures shows the fracture site as two outcroppings of bone, as though the long bone has collapsed or ‘buckled.’ This appearance also resembles the horns of a bull viewed head-on, hence the alternative nomenclature – ‘torus’ fracture. Others mention the fracture resembling the base of a Greek column or torus.

buckle fracture xray

Figure 3.  Buckle fracture on x-ray.  Adopted from [21].

However, if there is a fracture with a cortical breach, it is termed a greenstick fracture if unicortical, or a complete fracture if bicortical. Other sources may call this a nondisplaced complete fracture and classify this opposed to the displaced complete fracture.  Buckle fractures are incredibly common injuries that present to the emergency department, which are invariably always managed conservatively, and do not routinely require orthopedic input.

Greenstick Fracture xray

Figure 4.  Greenstick or complete nondisplaced fracture.  Adopted from [21].

Of all pediatric injuries, fractures constitute around 25% of hospital attendance.[3] Distal radius and buckle fractures make up 27.2%, which, by far, is the most common bone to be injured and sustain a buckle fracture.[4] Specifically, 50% of pediatric wrist fractures are buckle fractures.[5] These injuries occur throughout the pediatric age range, but particularly common between the ages of 7 to 12 years old.

physical examination

Patients with radius or ulna fractures often present with reduced range of motion in the joint adjacent to the fracture (i.e., wrist for distal fracture and elbow for proximal fracture) [6].  Among the examination findings that suggest a wrist fracture, painful dorsiflexion is the most sensitive (95.7%) and ecchymosis is the most specific (97.8%) [5].  Additional predictors of a distal fracture include wrist edema, deformity, and pain with forearm pronation [5].  Proximal fractures often cause limited forearm pronation or supination and limited elbow flexion or extension.

Distal radius defect

Figure 5.  Distal radius deformity on physical examination.  Adopted form [21].

The essential elements in the evaluation of distal radial fractures are history and physical. These will guide a clinician in deciding what further imaging to obtain. X-rays or plain radiographs are the standard imaging modality in the diagnosis of distal radius fractures. X-rays examination should look for radial height, radial inclination, radial shift, volar tilt, ulnar variance, ulnar styloid fracture, and DRUJ widening.

Radial variance xray

Figure 6.  Radial inclination description and measurement.  Adopted from [21]. 

Radial volar tilt xray

Figure 7.  Volar tilt explanation and measurement.  Adopted from [21].

imaging

Computed tomography (CT) images may be necessary if X-rays are equivocal, but the history and physical examination are strongly suggestive of a fracture. CT imaging may also be useful in subsequent surgical planning for fractures that will go to the operating suite for fixation, especially intra-articular fractures. MRI adds little utility over X-ray and CT in the diagnosis of distal radius fractures but may be useful if ligamentous disruption is suspected.

Another possible tool for sports medicine practitioners is the ultrasound (US).  One large meta-analysis showed that ultrasound has a high accuracy for the diagnosis of distal forearm fractures in children when used by proper viewing method [17]. One of the main advantages is the absence of exposure to ionizing radiation. Because children are up to four times more radiation sensitive and have a higher risk of being exposed to cumulative doses of radiation over time [5–9], ultrasound has received greater interest in this age group.

Whether ultrasound can be used as a primary screening tool is currently under debate [18]. It has been suggested that ultrasound only provides additional value under special circumstances, like the pre-hospital environment, disaster areas, developing countries, suspicion of occult fracture in poorly ossified bones, pregnant patients and to reduce exposure to serial direct radiographs in fracture reduction [19]. An important feature in this debate is the actual diagnostic accuracy of ultrasound for detecting forearm fractures.  The systematic review concluded that using ultrasound for the diagnosis of distal forearm fractures in children using the 6-view method is a reliable method that equals conventional x-ray in diagnostic accuracy with a sensitivity of 97% and specificity of 95%.  [17]. 

Ultrasound buckle fracture 1

Image 8: US image of nondislaced distal radius buckle fracture.  Adopted from [17].

US buckle fracture ultrasound

Image 9.  US images 6 weeks after initial injury. Adopted from [17].

US studies forearm fracture buckle or torus

Figure 10. Forrest plot of US studies with distal forearm fractures.  Adopted from [17].

treatment

Conventionally, buckle fractures are treated with immobilization for two to six weeks, without the need for closed reduction [3,26]. A variety of nonoperative wrist immobilization can be used, from rigid casting to soft elastic bandage wraps [11-12]. Recently, the literature has praised more lenient treatment options that minimize patient limitations while providing equivalent immobilization when compared to below-elbow casts [13-14]. Removable splints and other flexible variations (e.g., Futura-type splint, soft bandage) have been shown to provide better mobility and quicker recovery of strength and range of motion (ROM) [15-16]. These options do not cause patients additional pain and have shown no added risk of secondary angulation or refracture at six months post-injury.

Greenstick fractures generally receive conservative management. Minimally displaced or non-displaced fractures should be splinted and then subsequently placed in short arm casts. Children under 5 with distal radius greenstick fractures can tolerate up to 35 degrees of lateral angulation and 10 degrees of AP angulation. Children between 5 to 10 years of age can tolerate up to 25 degrees of lateral angulation and 10 degrees of AP angulation. Children older than ten should have reduction to less than 20 degrees of lateral angulation and 0 degrees of AP angulation. Distal radius greenstick fractures should generally be left in a short arm cast for 4-6 weeks.

Greenstick fractures are more unstable than buckle fractures over time. They many times can continue to displace also after the first 2 weeks. In one large review of 311 distal radius fractures, the greenstick fractures displaced 5° on average, and continued to displace after the first 2 weeks [13]. No unmanipulated greenstick fractures were subsequently manipulated, despite multiple radiographic controls.

The remodeling potential is great in the distal radius of children, and even dorsal angulation over 20º can remodel completely [14]. It is therefore argued that dorsal angulation can be accepted [15]. Excellent long-term functional and anatomical results have been reported [16]. However, even though a deformed wrist in childhood will remodel over time, it is unknown what consequences the transient deformity will have with regard to physical development and participation in activities.

Complete fractures comprise around 20% of distal metaphyseal radius fractures in children. Fully displaced fractures leave the distal fracture fragment in an over-riding position, also called bayonet position, with shortening and angulation. Pin fixation can be used to stabilize the fracture after closed reduction. However, it has been questioned if reduction of over-riding distal radius fractures in children <11 years is necessary at all, because remodeling can correct shortening up to 10 mm and angulations up to 35° [20]. In general, remodeling can be counted as a part of definitive care, but this requires experience. There is no consensus concerning the “acceptable” alignment, treatment, and follow-up protocol of displaced distal metaphyseal forearm fractures in children.

Distal radius algorithm

Figure 10.  Algorithm for distal radius buckle fractures.  Adopted from [2].

Summary

In summary, buckle fractures are stable and there is debate on treatment.  They are inherently stable and some many providers use a “minimalist” approach with splinting and limited follow up.  Greenstick fractures are more unstable and continue to displace after 2 weeks. They are treated more like distal radius fractures in adults.  Complete fractures of the distal radius are uncommon in children, and highly unstable. A precise classification of fracture type at the time of diagnosis would identify a smaller subset of patients that require follow-up.

– More Wrist Pain from Sports Medicine Review: https://www.sportsmedreview.com/by-joint/wrist/

– Read More @ Wiki Sports Medicine: https://wikism.org/Wrist_Pain_(Main)

References

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  2. Gonzalez N, Lucas J P, Winegar A, et al. (May 12, 2022) A Review of Pediatric Distal Radius Buckle Fractures and the Current Understanding of Angled Buckle Fractures. Cureus 14(5): e24943
  3. Rennie L, Court-Brown CM, Mok JY, Beattie TF. The epidemiology of fractures in children. Injury. 2007 Aug;38(8):913-22.
  4. Baig MN. A Review of Epidemiological Distribution of Different Types of Fractures in Paediatric Age. Cureus. 2017 Aug 28;9(8):e1624.
  5. Naranje SM, Erali RA, Warner WC, Sawyer JR, Kelly DM. Epidemiology of Pediatric Fractures Presenting to Emergency Departments in the United States. J Pediatr Orthop. 2016 Jun;36(4):e45-8.
  6. Dua K, Abzug JM, Sesko Bauer A, et al. Pediatric distal radius fractures. Instr Course Lect. 2017;66:447-460
  7. Randsborg PH, Sivertsen EA: Distal radius fractures in children: substantial difference in stability between buckle and greenstick fractures. Acta Orthop. 2009, 80:585-9
  8. West S, Andrews J, Bebbington A, Ennis O, Alderman P: Buckle fractures of the distal radius are safely treated in a soft bandage: a randomized prospective trial of bandage versus plaster cast. J Pediatr Orthop. 2005, 25:322-5.
  9. Pountos I, Clegg J, Siddiqui A: Diagnosis and treatment of greenstick and torus fractures of the distal radius in children: a prospective randomised single blind study. J Child Orthop. 2010, 4:321-6.
  10. Handoll HH, Elliott J, Iheozor-Ejiofor Z, Hunter J, Karantana A: Interventions for treating wrist fractures in children. Cochrane Database Syst Rev. 2018, 12:CD012470. 
  11. Kennedy SA, Slobogean GP, Mulpuri K: Does degree of immobilization influence refracture rate in the forearm buckle fracture?. J Pediatr Orthop B. 2010, 19:77-81. 
  12. Pountos I, Clegg J, Siddiqui A. Diagnosis and treatment of greenstick and torus fractures of the distal radius in children: a prospective randomised single blind study. J Child Orthop. 2010 Aug;4(4):321-6
  13. Randsborg PH, Sivertsen EA. Distal radius fractures in children: substantial difference in stability between buckle and greenstick fractures. Acta Orthop. 2009 Oct;80(5):585-9
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