[Late ulnar paralysis. Study of a series of 17 cases]

Seventeen cases of late ulnar paralysis treated by neurolysis-transposition are reported. The clinical characteristics of these paralyses are emphasized: very prolonged symptom free interval, rapid onset and severe involvement. 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 undependable: 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 step of 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.