Comparison of Different Locking Mechanisms in Total Hip Arthroplasty: Relative Motion between Cup and Inlay.

Sebastian Jaeger,Steffen Braun,Stefan Schroeder,Nicholas A Beckmann,Maximilian Uhler

doi:10.3390/ma13061392

Sebastian Jaeger, Steffen Braun + Show 3 more

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https://doi.org/10.3390/ma13061392

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Abstract

The resulting inflammatory reaction to polyethylene (PE) wear debris, which may result in osteolysis, is still considered to be a main reason for aseptic loosening. In addition to the primary wear in hip joint replacements caused by head-insert articulation, relative motions between the PE liner and the metal cup may cause additional wear. In order to limit this motion, various locking mechanisms were used. We investigated three different locking mechanisms (Aesculap, DePuy, and Zimmer Biomet) to address the resulting relative motion between the acetabular cup and PE liner and the maximum disassembly force. A standardized setting with increasing load levels was used in combination with optically based three-dimensional measurements. In addition the maximum disassembly forces were evaluated according to the ASTM F1820-13 standard. Our data showed significant differences between the groups, with a maximum relative motion at the maximum load level (3.5 kN) of 86.5 ± 32.7 µm. The maximum axial disassembly force was 473.8 ± 94.6 N. The in vitro study showed that various locking mechanisms may influence cup-inlay stability.

Highlights

Total hip arthroplasty (THA) is one of the most successful orthopedic procedures in joint replacement [1,2]
The mean resulting maximum relative motion in XYZ-direction for each load level and all investigated cup designs are shown in Table 1 and Figure 5
Wear particles can cause osteolysis an articulation, wear couldExisting be a consequence of proved the backside wear of the convex side of the linermain publications that, to the PE

Summary

Introduction

Total hip arthroplasty (THA) is one of the most successful orthopedic procedures in joint replacement [1,2]. The resulting inflammatory reaction to polyethylene (PE) wear debris, which may result in osteolysis [4], is still considered to be a main reason for aseptic loosening [5,6,7]. Wear debris production is thought to be the main factor limiting long-term survival of THA. It is known that can primary wear processes at the articulation sliding surfaces of hip cup and femoral head play an essential role, but in addition, secondary PE wear takes place at the backside of the PE liners (backside wear) due to relative motion between cup and insert [8,9,10,11]. A non-conforming fit between cup and PE liner, in combination with increased relative motion, could lead to burnishing, gouging, scratching or third-body wear on the PE backside surface [12]. In order to limit the motion between the metal shell and the liner, various

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