Fracture Propagation Propensity of Ceramic Liners During Impingement-Subluxation

Abstract

Although improvements in materials engineering have greatly reduced fracture rates in ceramic femoral heads, concerns still exist for liners. Ceramics are vulnerable fracture due to impact, and from stress concentrations (point and line loading) such as those associated with impingement-subluxation. Thus, ceramic cup fracture propensity is presumably very sensitive to surgical cup positioning. A novel fracture mechanics finite element formulation was developed to identify cup orientations most susceptible to liner fracture propagation, for several impingement-prone patient maneuvers. Other factors being equal, increased cup inclination and increased anteversion were found to elevate fracture risk. Squatting, stooping and leaning shoe-tie maneuvers were associated with highest fracture risk. These results suggest that fracture risk can be reduced by surgeons’ decreasing cup abduction and by patients’ avoiding of specific activities.

Do Obesity and/or Stripe Wear Increase Ceramic Liner Fracture Risk? An XFEM Analysis

“…Fracture risk in this group increased with increased cup inclination (Appendix Fig. A3), similar to the behavior simulated using LEFM [11]. (Additionally, earlier LEFM work had identified increased fracture risk with increased anteversion.)…”

“…Finally, this investigation involved only two fracture-prone maneuvers. Although stooping and squatting have been previously observed [11] to represent among the greatest challenges to ceramic liner integrity, a seemingly limitless variety of impingement challenges obviously occurs in patient populations. Extension of the present XFEM formulation to investigate additional fracture-prone patient activity maneuvers is an inviting topic for further research.…”

“…The femoral component orientation was held constant at 16.5°of anteversion [29,40]. Two fractureprone motion challenges [11] were considered: stooping and Asian-style squatting. These input motions were determined from an inverse dynamics solution of a 47-muscle optimization model [27].…”

“…To date, however, performance of classical linear elastic fracture mechanics (LEFM) analysis has been the only available approach for that purpose. LEFM models [11] are logistically challenging, because they require extraordinary computational and analyst effort, because the location of crack nucleation must be known (or assumed) a priori, and because specialized fracture elements must be positioned accordingly. Additionally, simulation of actual fracture propagation involves ad hoc remeshing, which is extremely laborious even in two dimensions and which is intractable for threedimensional analysis.…”

Effect of microseparation on contact mechanics in metal‐on‐metal hip replacements—A finite element analysis

“…Scifert et al29 developed a contact model to study factors that can influence hip dislocation; Elkin et al30, 31, 32 extended the model to investigate the effect of subluxation and impingement for MoM bearings and fracture for CoC implants; Mak et al18, 24 calculated contact stress for edge loading due to microsepartion in CoC hip joints; Sariali et al33 also carried out similar predictions for CoC bearings. Experimentally, Sanders and Brannon34 developed a method to predict contact area on cup edge and compared with the Hertzian contact theory.…”