Angular stability locking plates are commonly used in proximal humeral fractures, especially in old patients with osteoporotic bones. These implants show good results in short and midterm follow-up, but complications are not uncommon. Here we present a case report to describe a case of early failure of a proximal angular stability plate implanted in a 72 years old female with a highly unstable two part proximal humeral fracture. An optical and metallurgic analysis was also conducted to study the modalities of failure. We concluded that anatomic reduction and restoration of the medial cortical support are crucial in order to minimize the mechanical load on the bone-metal interface and to prevent mechanical failure, in particular when the fracture rim drop in the weak point of the plate that was found in the proximal two symmetric holes (Holes E).
Keywords: Angular stability locking plate; Metallurgic plate analysis; Plate failure; Proximal humerus fracture.