SEDL / STP / STP1301-EB / STP12035S

Femoral Stem Fatigue Characteristics of Modular Hip Designs

Heim, CS
Engineering Associate, Engineering Associate and Director, Orthopaedic Research Laboratories, Mt. Sinai Medical Center, Cleveland, OH

Postak, PD
Engineering Associate, Engineering Associate and Director, Orthopaedic Research Laboratories, Mt. Sinai Medical Center, Cleveland, OH

Greenwald, AS
Engineering Associate, Engineering Associate and Director, Orthopaedic Research Laboratories, Mt. Sinai Medical Center, Cleveland, OH

Pages: 18    Published: Jan 1997

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Abstract

Modularity in total hip arthroplasty design has received increased citation in the literature. Clinical concerns in the application of these systems include structural compromise at metal-metal interconnections due to cyclic microdisplacements. A laboratory fatigue test method, incorporating proximal support was developed and utilized to determine performance characteristics for these systems. Structural fatigue curves for four modular systems currently in clinical use were obtained and compared to anticipated in vivo service loading conditions for the normal hip. The structural fatigue strength of these designs was at least 1.3 times the anticipated service load. The results demonstrate that the in vivo structural integrity of these systems should not be compromised by the presence of metal-metal interconnections.