Medical Fixation Device Fatigue Fracture Under Non-Weightbearing Conditions

Amidst a series of five ankle/lower leg surgeries over a two-year period, a failure analyst endured failure of a fixation device. The titanium alloy (Ti-6Al-4V) plate and one of the ten screws fractured after only one month under totally non-weightbearing conditions (i.e., knee scooter and crutches). Upon removal and receipt of the hardware, the failure analyst naturally performed visual examination and fractographic analysis of the broken plate and screw. High cycle fatigue was determined to be the failure mechanism of the plate and screw. The failure analyst will recount his surgical journey using numerous images and x-rays. The results of his failure analysis will be presented including SEM photomicrographs of both component fractures. Potential causes and contributing factors for the unexpected fatigue failure under non-weightbearing conditions will be proposed.