Published online Apr 18, 2024. doi: 10.5312/wjo.v15.i4.321
Peer-review started: December 30, 2023
First decision: January 16, 2024
Revised: January 28, 2024
Accepted: March 25, 2024
Article in press: March 25, 2024
Published online: April 18, 2024
Processing time: 107 Days and 17.5 Hours
The four components that make up the current dual-mobility artificial hip joint design are the femoral head, the inner liner, the outer liner as a metal cover to prevent wear, and the acetabular cup. The acetabular cup and the outer liner were constructed of 316L stainless steel. At the same time, the inner liner was made of ultra-high-molecular-weight polyethylene (UHMWPE). As this new dual-mobility artificial hip joint has not been researched extensively, more tribological research is needed to predict wear. The thickness of the inner liner is a significant compo
To make use of finite element analysis to gain a better understanding of the contact behavior in various inner liner thicknesses on a new model of a dual-mobility artificial hip joint, with the ultimate objective of determining the inner liner thickness that was most suitable for this particular type of dual-mobility artificial hip joint.
In this study, the size of the femoral head was compared between two diameters (28 mm and 36 mm) and eight inner liner thicknesses ranging from 5 mm to 12 mm. Using the finite element method, the contact parameters, including the maximum contact pressure and contact area, have been evaluated in light of the Hertzian contact theory. The simulation was performed statically with dissipated energy and asymmetric behavior. The types of interaction were surface-to-surface contact and normal contact behavior.
The maximum contact pressures in the inner liner (UHMWPE) at a head diameter of 28 mm and 36 mm are between 3.7-13.5 MPa and 2.7-10.4 MPa, respectively. The maximum von Mises of the inner liner, outer liner, and acetabular cup are 2.4–11.4 MPa, 15.7–44.3 MPa, and 3.7–12.6 MPa, respectively, for 28 mm head. Then the maximum von Mises stresses of the 36 mm head are 1.9-8.9 MPa for the inner liner, 9.9-32.8 MPa for the outer liner, and 2.6-9.9 MPa for the acetabular cup. A head with a diameter of 28 mm should have an inner liner with a thickness of 12 mm. Whereas the head diameter was 36 mm, an inner liner thickness of 8 mm was suitable.
The contact pressures and von Mises stresses generated during this research can potentially be exploited in estimating the wear of dual-mobility artificial hip joints in general. Contact pressure and von Mises stress reduce with an increasing head diameter and inner liner’s thickness. Present findings would become one of the references for orthopedic surgery for choosing suitable bearing geometric parameter of hip implant.
Core Tip: The dual mobility hip system has the potential to be a great big bearing articulation if its technology is combined with highly cross-linked polyethylene. The modern artificial hip joint design has two free articulations between four parts: the femoral head, the inner liner, the outer liner as a metal cover to reduce wear, and the acetabular cup. Several studies show that prosthetic implant wear might be predicted partly by computing contact pressure distribution and contact area during everyday activities. A more reliable method of distinguishing between ideal and reality models may be incorporating activities with severe loading and boundary conditions.