Forearm - Radius and Ulnar Shaft Fractures

Key Points:

  • The vast majority of pediatric radial and ulnar shaft fractures can be managed with closed treatment
  • Surgical indications include open fractures, unacceptable fracture deformity, compartment syndrome and re-fracture
  • Surgical options include flexible intramedullary nailing or open reduction and plating
  • Complications after treatment include loss of reduction, refracture, compartment syndrome, and hardware irritation

Description:

Pediatric forearm fractures are one of the most common injuries sustained by children.  Most forearm fractures in children can be treated non-operatively, however, the rate of operative management of pediatric forearm fractures is increasing (Flynn, 2010). Treatment recommendations are generally based on patient age, fracture characteristics, and associated injuries. 

Epidemiology:

Fractures of the radius and ulna account for the most common fractures in children under 14 years old. (Chung, 2001) Fractures of the radial shaft are the third most common fracture in children, after distal radius and supracondylar humerus fractures. (Cheng, 1999). The distal radial and ulnar physes account for approximately 80% of longitudinal forearm growth.  On average, the distal radial and ulnar physes close at age 17 in girls and 19 in boys, however, physiologic growth is likely complete prior to radiographic physeal closure. 

Clinical Findings:

Radial and ulnar shaft fractures most commonly occur after a fall onto an outstretched arm.  In fractures requiring reduction, clinical deformity is usually readily apparent.  Patients should be assessed for evidence of open fracture, ipsilateral fracture proximal or distal to the forearm, and baseline neurovascular status as these will all influence ultimate treatment. 

Imaging Studies:

Standard AP and lateral radiographs should be obtained when evaluating these injuries.  There are acceptable radiographic limits for residual displacement, angulation, and rotation of diaphyseal forearm fractures; in general, however, these limits become more stringent as patients approach skeletal maturity. (Vittas, 1991)  Although controversy exists in the literature, generally accepted criteria for satisfactory residual deformity of diaphyseal forearm fracture in patients ≤10 years old include, angulation <15°, rotation <45°, <1 cm of shortening, and 100% translation.  In those >10 years old, angulation <10° and rotation <30° are acceptable.  Shortening >1 cm and/or bayonet apposition is generally unacceptable in older patients.  A potential shortcoming of using radiographic criteria alone when determining treatment of pediatric diaphyseal forearm fractures is the assessment of the “true” fracture angulation, since radiographs are not necessarily taken orthogonal to the plane of maximal deformity. (Bar, 1989)  Additionally, radiographs following an acute injury are often suboptimal because of difficulty positioning the forearm due to patient apprehension.  Despite this, most authors abide by the radiographic criteria as described above.

Etiology:

It is useful to divide these injuries based on fracture location.  This will influence closed reduction techniques since the deforming muscular forces acting upon the fractured segments will depend upon the level of the fracture.  The primary deforming force acting on proximal third, middle third, and distal third diaphyseal forearm fractures are the distal biceps/supinator, pronator teres, and pronator quadratus muscles respectively.  Techniques that counteract these deforming forces should therefore, be employed during closed reduction.  Once reduced, the bicipital tuberosity and radial styloid are useful landmarks to assess rotational alignment since they are oriented roughly 180° from each other.  Malunion of the radial or ulnar shaft will limit forearm motion and can have significant effects on upper extremity function. (Johari, 1999; Price, 1990)

Treatment:

A vast majority of pediatric radial and ulnar shaft fractures can be successfully treated by closed means although interest in surgical treatment has continued to increase (Flynn, 2010; Westacott, 2012) despite the relative lack of high-quality evidence supporting this trend. (Eismann, 2013; Franklin, 2012)  While most fractures can be adequately treated non-operatively, absolute surgical indications include open fractures and fractures associated with radio-capitellar (Monteggia) or distal radio-ulnar joint (Galleazzi) instability; relative surgical indications include unacceptable residual deformity, loss of reduction, refracture, compartment syndrome, and fractures in those nearing or at skeletal maturity. (Price, 2008)  

Non-operative Treatment    

The standard of care for the treatment of pediatric diaphyseal forearm fractures remains non-operative treatment with closed reduction and casting.  An acceptable functional outcome with closed treatment is the rule in a majority of fractures. (Zionts, 2005; Jones, 1999; Sinikumpu, 2014)  Important principles to consider when choosing non-operative treatment include: obtaining adequate analgesia/anesthesia if closed manipulation is required, restoring adequate length, alignment, and rotation of the fracture, and careful application of a well-molded cast or splint.  Appropriate application of a cast or splint is one of the most important aspects of non-operative management of pediatric diaphyseal forearm fractures. (Kamat, 2012)  Principles of cast application that are important to consider include use of an optimal amount of cast padding (i.e. enough to protect the skin but not so excessive as to compromise cast molding), protection of bony prominences (such as the medial and lateral humeral epicondyles and olecranon process), and obtaining a good interosseous mold as well as a straight ulnar border to prevent re-displacement/loss of reduction. 

Greenstick fractures represent a unique type of diaphyseal forearm fracture in children because of the thick periosteal layer as well as the inherent elasticity of the immature skeleton.  By definition, these fractures have incomplete cortical disruption as well as plastic deformation located at the apex of the fracture.  These fractures tend to have a significant rotational component and fracture reduction maneuvers should take this into account. (Wright, 2012)  Classically, greenstick fractures with apex volar angulation are thought to be due to a supination force, while those with apex dorsal angulation are due to a pronation force. (Rang, 1974)  A general rule of thumb when reducing greenstick fractures in children is to rotate the palm towards the apex of the deformity(Noonan, 1998).

Operative Treatment

When indicated, surgical options for the treatment of pediatric diaphyseal forearm fractures include elastic intramedullary nailing and open reduction internal fixation with standard plating techniques.  In general, in the acute setting, fracture characteristics and surgeon preference will dictate the choice of operative technique and the literature supports both for the treatment of pediatric forearm fractures. (Wall, 2012; Reinhardt, 2008; Martus, 2013; Kang, 2011)  Advantages of plate fixation include the ability obtain a direct, anatomic fracture reduction and rigid fixation; disadvantages include the need for more invasive dissection both during initial fracture fixation and plate removal (if elected).  Advantages of flexible intramedullary nailing include the ability to provide fracture fixation without disrupting the fracture site, insertion of implants via percutaneous techniques, and the relative ease of insertion (with experience).  Disadvantages include decreased ability to obtain an anatomic reduction because of the use (by definition) of indirect reduction techniques, hardware irritation, and the need for a second procedure for implant removal.  

Complications:

Common complications after closed treatment of diaphyseal forearm fractures in children include re-displacement/loss of reduction, re-fracture, and forearm stiffness/loss of motion.  Factors related to loss of reduction include increased initial fracture displacement, inability to obtain an anatomic reduction during initial treatment (McQuinn, 2012), and poor cast application as measured by cast index. (Kamat, 2012)  Re-fracture after treatment of diaphyseal forearm fractures can occur in up to 5% of injuries and tend to occur within 6 weeks of discharge from orthopaedic care. (Tisosky, 2014) Loss of motion after healing of forearm fractures is most directly related to residual angulation, however, may also be due to soft tissue causes such as fibrosis of the interosseous membrane or contracture of the interosseous ligament. (Noonan, 1998) Complications after operative treatment include infection, neuropraxia, hardware irritation (particularly from flexible intramedullary nails), tendon rupture (particularly extensor pollicus longus), radioulnar synostosis, compartment syndrome, and delayed union. (Martus, 2013)  Compartment syndrome is more common in open injuries, forearm fractures with associated distal humerus fractures (i.e. “floating elbow”) (Blakemore, 2000) and in those with difficult to reduce fractures requiring extensive surgical efforts. (Yuan, 2004; Blackman, 2014).  

References:

  1. Bar, H.F. and H. Breitfuss, Analysis of angular deformities on radiographs. J Bone Joint Surg Br, 1989. 71(4): p. 710-1.
  2. Blackman, A.J., et al., Acute compartment syndrome after intramedullary nailing of isolated radius and ulna fractures in children. J Pediatr Orthop, 2014. 34(1): p. 50-4.
  3. Blakemore, L.C., et al., Compartment syndrome in ipsilateral humerus and forearm fractures in children. Clin Orthop Relat Res, 2000(376): p. 32-8.
  4. Cheng, J.C., et al., A 10-year study of the changes in the pattern and treatment of 6,493 fractures. J Pediatr Orthop, 1999. 19(3): p. 344-50.
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  20. Sinikumpu, J.J., et al., Nonoperatively treated forearm shaft fractures in children show good long-term recovery. Acta Orthop, 2014. 85(6): p. 620-5.
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  25. Wright, P.B., et al., Radius crossover sign: an indication of malreduced radius shaft greenstick fractures. J Pediatr Orthop, 2012. 32(4): p. e15-9.
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Top Contributors:

Aristides Cruz MD