In pediatric Monteggia fractures the annular ligament is commonly interposed in the radiocapitellar joint. Tan et al reviewed their treatment of 35 children with Type I and Type III Monteggia fractures. All radial heads were explored and the interposed annular ligament was stretched out of the joint space. They noted that none of the patients has any recurrent dislocation or subluxation. Bado initially described and classified Monteggia fractures. The most common injury pattern is an extension type 1 with anterior radial head dislocation and apex anterior ulnar shaft fracture. The apex of the ulna fracture determines the direction of the radial head subluxation or dislocation. Adults typically require ORIF of the ulna. These fractures in children are often treated non-operatively with closed reduction if the ulna fracture is transverse and stable. Type III is the one most commonly associated with irreducibility of the radial head because of interposition of the annular ligament. The incidence of posterior interosseous nerve injury is high with this lesion. The nerve deficit usually completely resolves rapidly and spontaneously. Ring et al in their review stress the importance of an anatomic reduction of the ulna to restore the reduction of the radial head.
Ring D, Jupiter JB, Waters PM. Monteggia fractures in children and adults. J Am Acad Orthop Surg. 1998 Jul-Aug;6(4):215-24. Review.
PMID:9682084 (Link to Abstract)
Tan JW, Mu MZ, Liao GJ, Li JM. Pathology of the annular ligament in pediatric Monteggia fractures. Injury. 2008 Apr;39(4):451-5. Epub 2007 Nov 19.
PMID:18005963 (Link to Abstract)