Mechanical failures of internal fixation in T and Y fractures of the distal humerus.

To evaluate the factors resulting in mechanical failures of internal fixation of distal T-type and Y-type humeral fractures, we reviewed the clinical course and final results in 61 consecutive cases treated with AO-ASIF internal fixation devices. The patients were followed for at least 2 years (range, 2-11 years). Mechanical failure occurred in 18 cases (29.5%). In 12 patients this resulted from an unstable fixation. Severe osteoporosis was present in four patients. In two patients no specific causative factor could be detected. A second osteosynthesis was undertaken in five patients, and four additional patients were later operated on for nonunion. The functional outcome after these mechanical failures was, unexpectedly, poor in only 6 of the 18 patients. In spite of this comforting finding, the conclusion is that to minimize the failure rate in the management of these demanding fractures strict adherence to the correct technical fixation principles is mandatory, and when the bone is very osteoporotic a nonsurgical approach seems advisable.