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Cemented short‐stem total hip arthroplasty: Characteristics of line‐to‐line versus undersized cementing techniques using a validated CT‐based finite element analysis
Author(s) -
Azari Fahimeh,
Sas Amelie,
Kutzner Karl P.,
Klockow Andreas,
Scheerlinck Thierry,
Lenthe G. Harry
Publication year - 2021
Publication title -
journal of orthopaedic research®
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.24887
Subject(s) - finite element method , stiffness , cadaveric spasm , total hip arthroplasty , femur , materials science , orthodontics , structural engineering , medicine , surgery , composite material , engineering
Abstract Short stems are becoming increasingly popular in total hip arthroplasty as they preserve the bone stock and simplify the implantation process. Short stems are advised mainly for patients with good bone stock. The clinical use of short stems could be enlarged to patients with poor bone stock if a cemented alternative would be available. Therefore, this study aimed to quantify the mechanical performance of a cemented short stem and to compare the “undersized” cementing strategy (stem one size smaller than the rasp) with the “line‐to‐line” technique (stem and rasp with identical size). A prototype cemented short stem was implanted in eight pairs of human cadaveric femora using the two cementing strategies. Four pairs were experimentally tested in a single‐legged stance condition; stiffness, strength, and bone surface displacements were measured. Subject‐specific nonlinear finite element models of all the implanted femora were developed, validated against the experimental data, and used to evaluate the behavior of cemented short stems under physiological loading conditions resembling level walking. The two cementing techniques resulted in nonsignificant differences in stiffness and strength. Strength and stiffness as calculated from finite element were 8.7 ± 16% and 9.9 ± 15.0% higher than experimentally measured. Displacements as calculated from finite element analyses corresponded strongly ( R 2 ≥ .97) with those measured by digital image correlation. Stresses during level walking were far below the fatigue limit for bone and bone cement. The present study suggests that cemented short stems are a promising solution in osteoporotic bone, and that the line‐to‐line and undersized cementing techniques provide similar outcomes.