Multi-patient finite element simulation of keeled versus pegged glenoid implant designs in shoulder arthroplasty

Abstract

This study investigates the mechanical behaviour of keeled and pegged implant designs used in shoulder arthroplasty for the first time using multiple 3D models. Thus, this study should provide valuable insights into the preferable use of either of these two controversial implant designs. Three-dimensional models of a scapula were derived from the CT scans of five patients, and an inter-patient-specific finite element analysis with special attention to bone density and boundary conditions was carried out. A distinct decrease in the investigated parameters was evident with the pegged implant in all of the patients, specifically for the implant and the bone cement. The relevance of the stress reduction within the bone is minor, whereas the reduction in the stress of the bone cement contributes to an increase in the bone cement survival. The particular construction of the pegged implant provides better stability and therefore supports bone ingrowth. The large variations between the patients show the necessity of patient-specific simulations and the use of multiple models to derive valuable results. In the conducted inter-patient-specific FEA, the pegged glenoid implants were found to exhibit superior behaviour compared with keeled implants. The results confirm the general clinical findings and demonstrate the FEA as a valuable tool in prosthetic and orthopaedic problems.

Mechanical behavior of hybrid glenoid components compared to all-PE components: a finite element analysis

“…For all scapulae, the boundary between cortical and trabecular bone was differentiated in each slice, using the thresholding (trabecular bone < 20% of the maximum density [10]) and manual selection tools of the segmentation software. The bone density in each voxel was estimated by applying the method described by Pomwenger et al [11] (Additional file 1). Mean cortical () and mean trabecular () densities were first calculated, before the Young’s moduli () were assigned to the cortical and trabecular bone volumes according to the method proposed by Pomwenger et al [12] (Table 1).…”

“…Tied constraints were applied on the cortical and trabecular bone boundaries, and between the cement and cemented glenoid parts [11]. Sliding with friction and no‐penetration contact constraints were applied between bone and cement (coefficient of friction, 0.6) [11, 16, 17], and between the porous structures of the hybrid components and cortical and trabecular bone (coefficient of friction, 0.74) [18]. The five scapulae were anchored at their medial aspect and at the acromial clavicular joint (Fig.…”

Numerical Study of the Biomechanical Behaviour of the Different Implantation Methods of the Reverse Shoulder Replacement

“…For all the numerical models, a vertical force of 37 N, which represents the weight of the arm, was applied to the gravity center of humerus. Contact conditions with a friction coefficient μ = 0.07 were applied between the cup and the glenosphere [20]. All other contacts between the different parts are assumed to be totally linked (bilateral contact).…”

Experimental assessment of biomechanical properties in human male elbow bone subjected to bending and compression loads

“…Knowledge of the mechanical properties of the elbow bones aids in analytical as well as numerical simulations such as in evaluating stresses generated in the elbow joint at various flexion and extension angles 31 and postimplantation of prostheses. 32 Burkhart et al developed a finite element (FE) model to simulate the impact of forward fall on the distal radius bone. 33 The authors adopted an elastic modulus of 25.1 GPa, adopted from Burstein et al, 23 from experiments conducted on frozen femur cortical bone.…”