Evaluating the primary stability of standard vs lateralised cementless femoral stems – A finite element study using a diverse patient cohort

Al-Dirini, Rami; Martelli, Saulo; Huff, D.; Ju, Zhang; Clement, John G.; Besier, Thor F.; Taylor, Mark

doi:10.1016/j.clinbiomech.2018.09.002

Cited by 11 publications

(6 citation statements)

References 46 publications

(65 reference statements)

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“…Peak micromotions in the femoral stem/bone interface typically occur in the posteromedial region during activities of daily living. Al‐Dirini et al 34 conducted a FEA on a cohort of 31 femora to investigate the femoral micromotions for standard, lateral and coxa vara stem configurations for walking and stair climbing, recording the highest peak and median micromotions during both activities for the lateral stem configuration. Abdul Kadir et al 4 showed with a FEA model correlated to an in vitro micromotion experiment on four cadavers that an interference fit around 50 µm in the FEA model corresponds most closely to the situation of a press‐fit of an uncemented stem and reported micromotions in the upper stem zone of 50–150 µm.…”

Section: Discussionmentioning

confidence: 99%

Influence of offset on osseointegration in cementless total hip arthroplasty: A finite element study

Meisterhans,

Dimitriou,

Fasser

et al. 2024

Journal Orthopaedic Research

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Early aseptic loosening is caused by deficient osteointegration of the femoral stem due to increased micromotions and represents a common mode of failure in uncemented total hip arthroplasty (THA). This study hypothesized that a higher femoral offset, a smaller stem size and obesity increase femoral micromotion, potentially resulting in early aseptic loosening. A finite element analysis was conducted based on computed tomography segmented model of four patients who received a THA with a triple‐tapered straight stem (Size 1, 3, 6). The influence of femoral stem offset (short neck, standard, lateral), head length (S to XXL), femoral anteversion and obesity during daily activities of fast walking and stair climbing was analyzed. The micromotions for the femoral stem zones were compared to a threshold representing a value above which only partial osseointegration is expected. The minimum femoral offset configuration compared to the maximum offset configuration (short neck stem, S head vs. lateral stem, XXL head) leads to a relative mean micromotion increase of 24% for the upper stem zone. Increasing the body weight (body mass index 30–35 kg/m2) increases the micromotion by 20% for all stem zones. The obese population recorded threshold‐exceeding micromotions for stem sizes 1 and 3 for all offset configurations during stair climbing. Higher femoral offset, a smaller stem size, and higher loading due to obesity lead to an increase in micromotion between the prosthesis and proximal femur and represent a risk configuration for impaired osseointegration of a triple‐tapered straight stem, especially when these three factors are present simultaneously.

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Section: Discussionmentioning

confidence: 99%

Influence of offset on osseointegration in cementless total hip arthroplasty: A finite element study

Meisterhans,

Dimitriou,

Fasser

et al. 2024

Journal Orthopaedic Research

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“…Published population level studies have paved the way for ISCT by demonstrating the technical feasibility to study a specific patient risk on a large number of virtual patients. 1 , 2 , 12 , 31 , 38 , 40 , 44 These analyses generally considered one failure mode in complete isolation; however, clinical studies encompass the large number of patient risks that reflect the total performance of the medical device. Determination of the potential patient risks in scope of an ISCT is necessary to ensure the device performance is sufficiently addressed while maximizing the utility of the ISCT.…”

Section: Barriers To Isct Applicationsmentioning

confidence: 99%

“…27 , 42 , 47 , 48 Published population level studies have demonstrated the technical feasibility to assess a specific patient risk on a large number of virtual patients. 1 , 2 , 12 , 31 , 38 , 40 , 44 Further, regulators are increasingly open to use of computer-generated evidence. 46 , 47 ISCT has therefore the potential to become a new viable source for credible data on clinical device performance (Fig.…”

Section: Introductionmentioning

confidence: 99%

In Silico Clinical Trials in the Orthopedic Device Industry: From Fantasy to Reality?

et al. 2021

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The orthopedic device industry relies heavily on clinical evaluation to confirm the safety, performance, and clinical benefits of its implants. Limited sample size often prevents these studies from capturing the full spectrum of patient variability and real-life implant use. The device industry is accustomed to simulating benchtop tests with numerical methods and recent developments now enable virtual “in silico clinical trials” (ISCT). In this article, we describe how the advancement of computer modeling has naturally led to ISCT; outline the potential benefits of ISCT to patients, healthcare systems, manufacturers, and regulators; and identify how hurdles associated with ISCT may be overcome. In particular, we highlight a process for defining the relevant patient risks to address with ISCT, the utility of a versatile software pipeline, the necessity to ensure model credibility, and the goal of limiting regulatory uncertainty. By complementing—not replacing—traditional clinical trials with computational evidence, ISCT provides a viable technical and regulatory strategy for characterizing the full spectrum of patients, clinical conditions, and configurations that are embodied in contemporary orthopedic implant systems.

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“…Primary stability and stress shielding of a select few, mostly esoteric, THA femoral stem designs have been investigated using FEA. [11][12][13][14][15][16] To our knowledge, FEA has not previously been utilised to study the more clinically impactful issue of periprosthetic fracture risk as it varies widely across implanted femoral stem designs.…”

Section: Introductionmentioning

confidence: 99%

Short single-wedge stems have higher risk of periprosthetic fracture than other cementless stem designs in Dorr type A femurs: a finite element analysis

et al. 2020

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Background: The use of total hip arthroplasty (THA) femoral stems that transmit force in a favourable manner to the femur may minimise periprosthetic fractures. Finite element analysis (FEA) is a computerised method that analyses the effect of forces applied to a structure with complex shape. Our aim was to apply FEA to compare primary THA cementless stem designs and their association with periprosthetic fracture risk. Methods: 3-dimensional (3D) models of a Dorr Type A femur and 5 commonly used primary THA cementless stem designs (short single wedge, standard-length single wedge, modular, double-wedge metaphyseal filling, and cylindrical fully coated) were developed using computed tomography (CT) imaging. Implant insertion, single-leg stance, and twisting with a planted foot were simulated. FEA was performed, and maximum femoral strain along the implant-bone interface recorded. Results: Femoral strain was highest with short single-wedge stem design (0.3850) and lowest with standard-length single-wedge design (0.0520). Location of maximum femoral strain varied by stem design, but not with implant insertion, single-leg stance, or twisting with a planted foot. Strain was as high during implant insertion as with single-leg stance or twisting with a planted foot. Conclusions: Our results suggest the risk of intraoperative and postoperative periprosthetic fracture with THA in a Dorr A femur is highest with short single-wedge stems and lowest with standard-length single-wedge stems. Consideration may be given to minimising the use of short single-wedge stems in THA. Implant-specific sites of highest strain should be carefully inspected for fracture.

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Evaluating the primary stability of standard vs lateralised cementless femoral stems – A finite element study using a diverse patient cohort

Cited by 11 publications

References 46 publications

Influence of offset on osseointegration in cementless total hip arthroplasty: A finite element study

Influence of offset on osseointegration in cementless total hip arthroplasty: A finite element study

In Silico Clinical Trials in the Orthopedic Device Industry: From Fantasy to Reality?

Short single-wedge stems have higher risk of periprosthetic fracture than other cementless stem designs in Dorr type A femurs: a finite element analysis

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