Biomechanics of a calcar loading and a shortened tapered femoral stem: Comparative in-vitro testing of primary stability and strain distribution

Journal of Experimental Orthopaedics

Ralf Bieger¹  Daniel Dornacher¹  Heiko Reichel¹  Tobias Freitag¹  Hartmuth Kiefer²  Anita Ignatius³  Lutz Dürselen³ 

[1] Department of Orthopaedic Surgery, Ulm University Medical Centre, Oberer Eselsberg 45, 89081, Ulm, Germany;Department of Trauma and Orthopaedic Surgery, Lukas Hospital, Buende, Germany;Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre, Ulm University Medical Centre, Helmholtzstr. 14, 89081, Ulm, Germany;

关键词: Short stem;    Primary stability;    Stress-shielding;    Total hip arthroplasty;    Micromotions;    Cadaver;    Mechanical stress;    Metaphyseal;   

DOI  :  10.1186/s40634-021-00388-1

来源: Springer

【 摘 要 】

PurposeThe most common femoral short stems available on the market can, in principle, be divided with regard to their anchoring concepts into a calcar loading and a shortened tapered design. The purpose of this study was to compare the primary stability and stress-shielding of two short stems, which correspond to these two different anchoring concepts.MethodsUsing seven paired fresh frozen human cadaver femurs, primary axial and rotational stabilities under dynamic load (100–1600 N) were evaluated by miniature displacement transducers after 100,000 load cycles. Changes in cortical strains were measured before and after implantation of both stem types to detect implant-specific load transmission and possible stress-shielding effects.ResultsReversible and irreversible micromotions under dynamic load displayed no significant differences between the two implants. Implantation of either stem types resulted in a reduction of cortical strains in the proximal femur, which was less pronounced for the calcar loading implant.ConclusionsBoth short stems displayed comparable micromotions far below the critical threshold above which osseointegration may disturbed. Neither short stem could avoid proximal stress-shielding. This effect was less pronounced for the calcar loading short stem, which corresponds to a more physiological load transmission.

【 授权许可】

CC BY