Late ulnar paralysis. Study of seventeen cases.

: Seventeen cases of late ulnar paralysis treated by neurolysis-transposition are reported. The clinical characteristics of these paralysis are emphasized. A very prolonged symptom free interval, a rapid onset and a severe involvement. The ulnar transposition was most often done subcutaneously. Cubitus valgus and definite nerve compression proximal to the arcade of the flexor carpi ulnaris muscle are almost always present. The results as regards the neuropathy are notable: no patient is completely cured and only half are improved. An anatomical study of the nerve path shows the essential role, in the compression of the nerve, of the muscular arcade of the flexor carpi ulnaris muscle which acts in a way similar to the bridge of a violin. Hence, opening it longitudinally is the principal procedure of the neurolysis. This should be routine before the first signs of neuropathy occur in an elbow whose axis is out of alignment as a sequela of a childhood injury.