In 14 patients aged 38 to 87 years humeral shaft fractures were operat
ed on for failure of reduction, for delayed healing or for established
non-union with the Seidel interlocking nail system. In five patients
intraoperative technical problems were encountered. The healing rate w
as eight out of 12 patients. In cases of pseudarthrosis of the humeral
shaft, bone grafting or local osteosynthesis in addition to medullary
nailing seem advisable. The distal interlocking mechanism of the Seid
el nail should be improved.