Humerus Medial Epicondyle Fractures

Key Points:

  • Medial epicondyle fractures of the humerus account for 12-20% of pediatric elbow fractures.
  • Isolated fractures can occur secondary to direct trauma or avulsion forces.
  • 50% are associated with elbow dislocation.
  • Recent studies have highlighted the underestimation of fracture displacement seen on typical radiographic views
  • Indications for operative treatment include: fragment incarceration in the joint, open fracture, ulnar nerve entrapment, gross elbow instability, and participation in upper extremity athletics.

Description:

Medial epicondyle fractures may be associated with intra-articular incarceration of the displaced apophyseal fragment, elbow dislocation, ulnar nerve injury, and other upper extremity fractures. Good outcomes have been achieved with non-operative treatment for minimally displaced fractures, despite a high rate of nonunion (Pathy, 2015; Gottschalk, 2012; Farsetti, 2001).  In patients with displaced fractures, fixation yields stability, functional range of motion, and the ability to return to previous activity levels, including sports (Gottschalk, 2012; Patel, 2012; Haxhija, 2006; Bulut, 2005; Fowles, 1990). Complications may include stiffness, instability, deformity, superficial wound infection, and symptomatic nonunion. Competitive sports participation and increased functional and athletic demands of the pediatric and adolescent populations have resulted in new treatment controversies; including the reliability of measuring fracture displacement on radiographs, indications for operative treatment, and outcomes of operative and non-operative treatment.
 

Epidemiology:

Fractures of the medial epicondyle of the distal humerus account for approximately 12-20% of all pediatric elbow fractures and occur most frequently between the ages of 9 and 14 (Beaty, 2005). These fractures are four times more common in boys.  They are associated with elbow dislocation in 50% of children and incarceration of the medial epicondyle fragment within the elbow joint occurs in 15-18% of children (Beaty, 2005). Associated ulnar nerve dysfunction, most often transient, has been reported in 10-16% of patients (Beaty and Wilkens Editor, 2005; Patel, 2012).
 

Clinical Findings:

Anatomy:
The medial epicondyle ossification center is the second ossification center to appear at the distal humerus, at 5 to 7 years of age, and is the last distal humerus ossification center to fuse at 15-20 years old (Pathy, 2015; Beaty, 2005).  The medial epicondyle is an apophysis on the posterior-medial aspect of the distal humerus that serves as the origin of the flexor-pronator muscle mass and the primary origin of the ulnar collateral ligament (UCL). Injuries causing excessive traction on these structures may result in an epicondylar avulsion fracture (Pathy, 2015; Gottschalk, 2012; Beaty, 2005). In younger children, part of the joint capsule can extend up to the apophyseal line. In older children, as the distal humeral epiphysis enlarges with growth, the medial epicondyle is positioned more proximally and the fracture is typically extra-articular (Beaty, 2005). The ulnar nerve enters the cubital tunnel posterior to medial epicondyle and rests on the fibro-osseous surface directly posterior to the apophysis.

Imaging Studies:

Anteroposterior (AP), lateral, and internal oblique plain radiographs of the elbow are recommended in diagnosing medial epicondyle fractures. If a significant effusion exists, one must have a high index of suspicion for an elbow dislocation or additional fractures around the elbow (Beaty, 2005). Elbow dislocations frequently reduce spontaneously, prior to presentation for medical attention. If the medial epicondyle appears at the level of the joint or is absent at its normal position, it should be suspected to be incarcerated within the joint (Gottschalk, 2012; Dodds, 2014).  Failure to recognize intra-articular entrapment of the epicondyle (Figure 1) can result in significant restriction of motion (Beaty, 2005).
 
The oblique view can be particularly useful as the direction of displacement (commonly anterior and distal) is often out of plane from the standard AP and lateral views.
 
Much of the controversy regarding medial epicondyle fractures relates to acceptable displacement. Variable intra-observer agreement with regard to measurement of displacement of medial epicondyle fractures, with low overall agreement has been reported (Pappas, 2010). Authors noted improved inter-observer agreement on the AP view but stated that agreement was still low overall. CT to evaluate the true displacement of medial epicondyle fractures has recently been evaluated.  Even in minimally displaced fractures, CT scans have demonstrated up to 1 cm of anterior displacement that was unrecognized on standard radiographic views (Edmonds, 2010). A recent cadaveric study suggested use of a distal humerus axial view.  It has been shown to have significant intra-observer correlation and allows the surgeon reproducible evaluation of displacement at significantly reduced radiation load to the patient (Souder, 2015).


Fig. 1 Medial epicondyle fracture with incarceration of the fragment in the elbow joint


Fig. 2 Medial epicondyle fracture associated with elbow dislocation


Fig. 3 Displaced medial epicondyle fracture

Etiology:

Medial epicondyle fractures can be caused by either direct trauma to the elbow or, more commonly, an avulsion injury (Pathy, 2015: Gottschalk, 2012; Beaty, 2005). Avulsion fractures can occur via multiple mechanisms. Those caused by excessive tension in the flexor pronator mass can occur with a valgus force on the elbow during a fall on an outstretched hand with the elbow extended. Isolated avulsion fractures may also occur during eccentric loading of the flexor pronator mass during pitching, gymnastics, or wrestling.  Avulsion fractures can also be caused by traction on the UCL during these types of activities or with a posterior elbow dislocation (Pathy, 2015; Gottschalk, 2012; Beaty, 2005).

Classification:
Several classification systems have been described for medial epicondylar humerus fractures. Wilkins classified fractures as acute or chronic, with acute fractures subdivided into four categories: nondisplaced, minimally displaced, significantly displaced, or incarcerated in the joint (Gottschalk, 2012; Beaty, 2005). Chronic injuries are related to tension stress injuries, as seen in in young baseball pitchers (Gottschalk, 2012).

Treatment:

Treatment of pediatric humeral medial epicondyle fractures is controversial.  Traditionally, these fractures have been managed non-operatively; often with a long arm cast for 3-4 weeks with the elbow flexed to 90°, with some advocating immobilizing the forearm in pronation. Nonsurgical management of elbow dislocations and of severely displaced medial epicondyle fractures have been reported historically to yield results similar to those of surgery, even when healed with fibrous union (Pathy, 2015; Gottschalk, 2012; Farsetti, 2001; Patel, 2012).
 
Surgical fixation has been recommended in the following settings: open fracture, fragment incarceration (Figure 1), concurrent elbow dislocation (Figure 2), fracture displacement >5 mm (Figure 3), and fractures in upper extremity athletes (Pathy, 2015; Gottschalk, 2012; Patel, 2012; Bulut, 2005; Fowles, 1990; Louahem, 2010).
 
Various techniques for reduction of an incarcerated fragment have been described, including use of an Esmarch elastic bandage to compress the soft tissues toward the fracture site to assist in the reduction (Louahem,  2010), and utilizing the Roberts maneuver (Gottshcalk, 2012; Beaty and Wilkens Ed., 2005).  The Roberts maneuver consists of applying a valgus stress on the elbow, with forearm supination and extension of the wrist and fingers, to utilize muscle forces in an attempt to extract the intra-articular fragment (Beaty, 2005). 
 
Options for surgical fixation include sutures, Kirschner wires (K-wires), cannulated screws, and excision of the fragment with advancement of the medial soft tissues (Namath, 2009; Pathy, 2015; Gottschalk, 2012; Patel, 2012; Bulut, 2005; Fowles, 1990).  Suture fixation is typically used only for very small or comminuted fragments. K-wires are used if the fragment is too small to accept a screw, typically in younger children. When using cannulated screws, the use of a washer can help increase surface area for compression (and thus better distribute the compressive force of the screw), avoid screw head comminution of the fragment, and prevent screw migration (Pathy 2015).
 
As the medial epicondyle is a posterior structure, the screw is typically oblique, directed from medial to lateral, and from posterior to anterior up the medial column. Care should be taken to avoid implant placement in the olecranon fossa that could result in implant impingement and loss of extension (Patel, 2012; Gottschalk, 2012).  Typically, a 3.5 or 4.0 mm partially threaded cannulated screw is used. Because of the compression gained from the partial threads, the screw does not need to be bicortical (Pathy, 2015).  Bicortical drilling or fixation may place the radial nerve at risk for injury along the distal third of the humerus. Surgeons may consider prone positioning for surgical fixation of displaced fractures.  Positioning of the arm with the patient prone allows the elbow to be flexed with pronation of the forearm and relative varus of the elbow.  This allows reduction without excessive traction on the fragment (Glotzbecker, 2012).

Complications:

The three most common complications with treatment of medial epicondyle fractures of thehumerus are loss of motion, cubitus valgus and bony nonunion (Gottschalk, 2012; Beaty, 2005).  Nonunion following nonoperative treatment of medial epicondyle fractures is common, but may be asymptomatic (Louahem, 2010; Pathy, 2015).

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References:

  1. Beaty JH, Kasser JR. The Elbow: Physeal Fractures, Apophyseal Injuries of the Distal Humerus, Osteonecrosis of the Trochlea, and T-Condylar Fractures. In: Beaty JH, Kasser JR, ed. Rockwood & Wilkins' Fractures in Children. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006.
  2. Bulut G, Erken HY, Tan E, Ofluoglu O, Yildiz M. [Treatment of medial epicondyle fractures accompanying elbow dislocations in children]. Acta orthopaedica et traumatologica turcica. 2005;39(4):334-340.
  3. Dodds SD, Flanagin BA, Bohl DD, DeLuca PA, Smith BG. Incarcerated medial epicondyle fracture following pediatric elbow dislocation: 11 cases. The Journal of Hand Surgery. 2014;39(9):1739-1745.
  4. Edmonds EW. How displaced are "nondisplaced" fractures of the medial humeral epicondyle in children? Results of a three-dimensional computed tomography analysis. The Journal of Bone and Joint Surgery. American volume. 2010;92(17):2785-2791.
  5. Farsetti P, Potenza V, Caterini R, Ippolito E. Long-term results of treatment of fractures of the medial humeral epicondyle in children. The Journal of Bone and Joint Surgery. American volume. 2001;83-A(9):1299-1305.
  6. Fowles JV, Slimane N, Kassab MT. Elbow dislocation with avulsion of the medial humeral epicondyle. The Journal of Bone and Joint Surgery. British volume. 1990;72(1):102-104.
  7. Glotzbecker MP, Shore B, Matheney T, Gold M, Hedequist D. Alternative Technique for Open Reduction and Fixation of Displaced Pediatric Medial Epicondyle Fractures. J Child Orthop. 2012;6(2):105-9.
  8. Gottschalk HP, Eisner E, Hosalkar HS. Medial epicondyle fractures in the pediatric population. The Journal of the American Academy of Orthopaedic Surgeons. 2012;20(4):223-232.
  9. Haxhija EQ, Mayr JM, Grechenig W, Hollwarth ME. [Treatment of medial epicondylar apophyseal avulsion injury in children]. Operative Orthopadie und Traumatologie. 2006;18(2):120-134.
  10. Kamath AF, Cody SR, Hosalkar HS. Open reduction of medial epicondyle fractures: operative tips for technical ease. Journal of Children's Orthopaedics. 2009;3(4):331-336.
  11. Louahem DM, Bourelle S, Buscayret F, et al. Displaced medial epicondyle fractures of the humerus: surgical treatment and results. A report of 139 cases. Archives of orthopaedic and trauma surgery. 2010;130(5):649-655.
  12. Pappas N, Lawrence JT, Donegan D, Ganley T, Flynn JM. Intraobserver and interobserver agreement in the measurement of displaced humeral medial epicondyle fractures in children. The Journal of Bone and Joint Surgery. American volume. 2010;92(2);322-327.
  13. Patel NM, Ganley TJ. Medial epicondyle fractures of the humerus: how to evaluate and when to operate. Journal of Pediatric Orthopedics. 2012;32 Suppl 1:S10-13.
  14. Pathy R, Dodwell ER. Medial epicondyle fractures in children. Current opinion in pediatrics. 2015; 27(1): 58-66.

Top Contributors:

Indranil Kushare, MBBS, DNB
Allan Beebe, MD