Medial Epicondyle Fracture of the Humerus

AP views of both elbows of an 18-year-old boy who sustained an injury to the right elbow.  There is an avulsion fracture (arrow) of the medial epicondyle of the right humerus. Radiograph of the left side demonstrates different areas of distal humeral structures from medial to lateral: medial epicondyle, trochlea, capitellum and lateral epicondyle. 

Facts:

• Common pediatric elbow fracture (3rd common, after supracondylar and lateral condylar fractures)
• Valgus strain at elbow joint
• Two main types: simple avulsion (1/2) and fracture-dislocation (occurring with lateral elbow dislocation; 1/2)
• Indications for surgery include 1) displaced fragment trapped in joint preventing reduction, 2) ulnar neuropathy, 3) valgus instability, 4) open fracture

Imaging:

• Look for displaced fragment trapped in the joint and degree of displacement because they might indicate surgery
• In patients less than 8 years, trochlea may be non-ossified and this may be confused with fracture of medial condyle, which is rarer and could be more complicated
• Another imaging Ddx is osteochondrosis

References:

Wilson JN. The treatment of fractures of the medial epicondyle of the humerus. J Bone J Surg 1960;42:778.

Gottschalk HP, Eisner E, Hosalkar HS. Medial epicondyle fracture sin the pediatric population. J Am Acad Orthop Surgeons 2012; 20:223.

Wheeless' Textbook of Orthopedics link