Pediatric ulnar mononeuropathy: report of 21 electromyography-documented cases and review of the literature.

Pediatric ulnar mononeuropathies are the most frequent upper extremity mononeuropathies seen in the electromyography laboratory at The Children's Hospital, Boston. Twenty-one children (12 boys and nine girls) with pediatric ulnar mononeuropathy, aged 5 to 18 years, were seen from 1979 to 1991. The causes included acute trauma in 11 children (52%), compression in five children (24%), entrapment in three children (14%), and indeterminate in two children (10%). The sites of nerve injury included the elbow in 10 children (48%), forearm in three children (14%), wrist in five children (24%), hand in one child (4%), and indeterminate in the remaining two children (10%). Prognosis is more favorable in nontraumatic (83% improved) pediatric ulnar neuropathies than with traumatic lesions (56% improved), with at least a 1-year follow-up.