Comparative analysis of orthopaedic scaffold fixation methods - a finite element study

Purpose: Critical-size bone defects (CSBD) are a serious challenge in current orthopaedics. Natural healing processes are insufficient, leading to complications such as muscle atrophy, joint stiffness, impaired limb function and reduced quality of life. Currently used autologous or allogeneic bone grafts have disadvantages, such as long surgery time, secondary injuries and immunological reactions. A promising alternative in the treatment of CSBD is the use of a scaffold. The key element of the effective use of scaffolds is their proper anchoring in the bone defect. The article presents numerical analyses of the effectiveness of selected anchoring methods of the scaffold in the bone. Methods: Scaffolds were placed in a 60 mm long CSBDs. Four methods of anchoring the scaffold in the bone were selected: locking plate, external ring, intramedullary nail and double anti-rotation wedge. A simulation of the forces generated during the entire gait cycle was performed. The parameters obtained were: Huber Mises Hencky (HMH) max stress, strain energy density (SED), sliding distance, frictional stress and bone-scaffold gap. Results: Based on the conducted research, it was determined that the most effective of the evaluated solutions, in terms of load transfer, were the use of external ring or double anti-rotation wedge. Conclusions: The conducted research confirm that in the treatment of CSBD, an effective solution is the use of a scaffold, which effectiveness can be improved with appropriate anchoring method.