Finite element analysis of the crack emanating to cavity in the bone cement of the hip prosthesis

The analysis of elliptical cracks emanating from cavities in polymethyl-methacrylate (PMMA) surgical cement is crucial for understanding loosening in total hip prostheses, as cement failure is a primary cause of this issue. Understanding fracture mechanismsis vital for improving the durability of cemented prostheses. Predicting crack propagation paths can help identify high-risk areas using medical imaging. This study focuses on the behavior of cracks emanating from cavities within the orthopedic cement, using a realistic model. The crack behavior is analyzed in terms of the evolution of stress intensity factors (SIFs) in Modes I, II, and III, applying the maximum tangential stress criterion. The fracture analysis considers the crack size relative to the cavity, its orientation, and its location in the orthopedic cement. The finite element method specifically examines elliptical cracks along the cement, focusing on the effect of the distance between cracks emanating from cavities and nearby defects on SIFs. The orientation of these cracks significantly influences SIF magnitudes and modes, affecting the direction and stability of crack propagation. The study reveals that the proximal lateral part experiences the highest stresses, with a notable increase in SIFs in Modes I and II, particularly where crack interaction occurs. The proximal medial part follows, while the distal part is predominantly subjected to compressive stresses.