Biomechanics of short hip endoprostheses — The risk of bone failure increases with decreasing implant size

Bishop, Nick; Burton, Andrew; Maheson, M; Morlock, Michael M.

doi:10.1016/j.clinbiomech.2010.04.013

Cited by 44 publications

(28 citation statements)

References 28 publications

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“…This limit on safe radial stress will vary with the bone quality and structure. In addition, stresses due to post‐operative loading will superimpose on the press‐fit stresses . If a “safe” radial stress magnitude were known for a given patient, the results of this study could be used to define implantation conditions to achieve maximum fixation strength.…”

Section: Discussionmentioning

confidence: 99%

Influence of trabecular bone quality and implantation direction on press‐fit mechanics

Damm

Morlock

Bishop

2016

Journal Orthopaedic Research

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Achieving primary stability of uncemented press-fit prostheses in patients with poor quality bone can involve axial implantation forces large enough to cause bone fracture. Radial implantation eliminates intraoperative impaction forces and could prevent this damage. Platens of two commercial implant surfaces ("Beaded" and "Flaked") were implanted onto trabecular bone specimens of varying quality in a press-fit simulator. Samples were implanted with varying interference, either axially (shear) or radially (normal). Push-in and pull-out forces were measured to assess stability. Microstructural changes in the bone were determined from μCT analysis. For force-defined implantation analysis, push-in and pull-out forces both increased proportionally with increasing radial force, independent of implantation direction, bone quality or implant surface. For position-defined implantation analysis, pull-out forces were generally found to increase with interference and to be greater for radial than axial implantation direction, and to be lower for poor quality bone. Bone density increased locally at the tested interface due to implantation, in particular for the Beaded surface under axial implantation. If a safe radial stress can be determined for cortical bone in a particular patient, the associated implantation force, and pull-out force which represents primary stability, can be directly derived, regardless of implantation direction, bone quality or implant surface. Radial implantation delivers primary stability that is no worse than that for axial implantation and may eliminate potentially damaging impaction forces. Development of implant designs based on this principal might improve implant fixation. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:224-233, 2017.

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Section: Discussionmentioning

confidence: 99%

Influence of trabecular bone quality and implantation direction on press‐fit mechanics

Damm

Morlock

Bishop

2016

Journal Orthopaedic Research

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“…These published results and expectations assisted in expanding indications for shorter femoral implants, even in older patients with poorer bone quality . However, a biomechanical study demonstrated an increased risk of periprosthetic fractures after implantation of a short stem in osteoporotic bone . Even though the concept of short stem prostheses was introduced about 30 years ago, quite recently an increasing number of femoral short stem designs are being launched by various manufacturers .…”

mentioning

confidence: 99%

Biomechanics of a short stem: In vitro primary stability and stress shielding of a conservative cementless hip stem

et al. 2013

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Short stem prostheses provide conservative surgery and favorable metaphyseal load transmission. However, clinical longterm results are lacking. Therefore, in vitro trials can be used to predict bone-implant performance. In this in vitro study, primary stability and stress shielding of a new cementless short stem implant was evaluated in comparison to a straight stem using nine pairs of human cadaver femurs. Primary stability, including reversible micromotion and irreversible migration, was assessed in a hip simulator. Furthermore, changes in the pattern of cortical strain were evaluated. The short stem was more resistant to reversible micromotion and irreversible migration into retroversion. Axial stability was similar, with mean reversible micromotions of 9 mm for the short stem and 7 mm for the straight stem. Proximal load transmission was more physiological with the short stem, though both implants could not avoid stress shielding in Gruen zones 1 and 7. Primary stability of the short stem prosthesis was not negatively influenced compared to the straight shaft. Furthermore, proximal femoral strain pattern was more physiological after insertion of the short stem prosthesis. ß

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“…Il semble également déraisonnable d'implanter une tête en céramique de grand diamètre sur une tige fémorale courte, en raison de ce même risque de contraintes trop élevées transmises à l'interface tigeimplant [35].…”

Section: Têtes En Céramique De Grand Diamètreunclassified

Le diamètre des têtes fémorales des PTH de première intention

Girard¹

2014

Conférences d'Enseignement 2014

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Biomechanics of short hip endoprostheses — The risk of bone failure increases with decreasing implant size

Cited by 44 publications

References 28 publications

Influence of trabecular bone quality and implantation direction on press‐fit mechanics

Influence of trabecular bone quality and implantation direction on press‐fit mechanics

Biomechanics of a short stem: In vitro primary stability and stress shielding of a conservative cementless hip stem

Le diamètre des têtes fémorales des PTH de première intention

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