Primary Stability of Collared and Collarless Cementless Femoral Stems – A Finite Element Analysis Study

Watanabe, Ryunosuke; Mishima, Hajime; Totsuka, Sho; Nishino, Tomofumi; Yamazaki, Masashi

doi:10.1016/j.artd.2023.101140

Cited by 9 publications

(5 citation statements)

References 25 publications

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“…Our analyses also showed that indicators for stem fixation, such as spot welds, pedestal formation, and stress shielding were similar between the collared and non-collared groups, further refuting concerns over under-sized stems resulting in delayed stem fixation. These findings are similar to previous studies that have also reported comparable or improved outcomes in terms of stem fixation for collared versus non-collared stems [38,39]. In their finite element analysis, Watanabe et al [38] measured the micro-motion at the stem-bone interface between collared and non-collared stems.…”

Section: Discussionsupporting

confidence: 85%

“…These findings are similar to previous studies that have also reported comparable or improved outcomes in terms of stem fixation for collared versus non-collared stems [38,39]. In their finite element analysis, Watanabe et al [38] measured the micro-motion at the stem-bone interface between collared and non-collared stems. Their results showed that collared stems demonstrated equal to improved stability when a gap was left between the collar and the calcar and when the collar was in contact with the calcar, respectively.…”

Section: Discussionsupporting

confidence: 85%

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Radiological Comparison of Canal Fill between Collared and Non-Collared Femoral Stems: A Two-Year Follow-Up after Total Hip Arthroplasty

Ashkenazi,

Benady,

Ben Zaken

et al. 2024

J. Imaging

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Collared femoral stems in total hip arthroplasty (THA) offer reduced subsidence and periprosthetic fractures but raise concerns about fit accuracy and stem sizing. This study compares collared and non-collared stems to assess the stem–canal fill ratio (CFR) and fixation indicators, aiming to guide implant selection and enhance THA outcomes. This retrospective single-center study examined primary THA patients who received Corail cementless stems between August 2015 and October 2020, with a minimum of two years of radiological follow-up. The study compared preoperative bone quality assessments, including the Dorr classification, the canal flare index (CFI), the morphological cortical index (MCI), and the canal bone ratio (CBR), as well as postoperative radiographic evaluations, such as the CFR and component fixation, between patients who received a collared or a non-collared femoral stem. The study analyzed 202 THAs, with 103 in the collared cohort and 99 in the non-collared cohort. Patients’ demographics showed differences in age (p = 0.02) and ASA classification (p = 0.01) but similar preoperative bone quality between groups, as suggested by the Dorr classification (p = 0.15), CFI (p = 0.12), MCI (p = 0.26), and CBR (p = 0.50). At the two-year follow-up, femoral stem CFRs (p = 0.59 and p = 0.27) were comparable between collared and non-collared cohorts. Subsidence rates were almost doubled for non-collared patients (19.2 vs. 11.7%, p = 0.17), however, not to a level of clinical significance. The findings of this study show that both collared and non-collared Corail stems produce comparable outcomes in terms of the CFR and radiographic indicators for stem fixation. These findings reduce concerns about stem under-sizing and micro-motion in collared stems. While this study provides insights into the collar design debate in THA, further research remains necessary.

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Section: Discussionsupporting

confidence: 85%

Section: Discussionsupporting

confidence: 85%

Radiological Comparison of Canal Fill between Collared and Non-Collared Femoral Stems: A Two-Year Follow-Up after Total Hip Arthroplasty

Ashkenazi,

Benady,

Ben Zaken

et al. 2024

J. Imaging

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“…Patients with collared stems that achieve good collar-calcar contact have increased stability during flat-walking and stair-climbing, compared to patients with collared stems without collar-calcar contact, who have stability similar to patients with collarless stems [ 21 ]. Collar-calcar contact has also been shown to reduce the risk of periprosthetic fracture [ 22 , 23 ].…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have shown that attaining contact between the prosthesis stem collar and the femoral calcar intraoperatively during THA increased stability and reduced the rate of periprosthetic fracture [ [21] , [22] , [23] ]. Recent research has begun to explore how collar-calcar contact may be able to reduce the rate of subsidence as well [ 24 ].…”

Section: Introductionmentioning

confidence: 99%

Does Lack of Initial Collar-Calcar Contact Influence Performance of Collared Cementless Femoral Stems?

Weiner,

Woelfle,

et al. 2024

Arthroplasty Today

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“…However, this method can only measure the strain at the point where the gauge is used; therefore, it is arduous to observe the entire femur. Reports indicate that finite element analysis (FEA) using computed tomography (CT) data is a useful method for evaluating stress distribution and stem fixation of the femur after THA [ 10 , 11 , 23 , 27 , 32 ]. In recent years, as computer performance has improved, FEA has become widely used.…”

Section: Introductionmentioning

confidence: 99%

Bone mineral density changes around the stem correlate with stress changes after total hip arthroplasty: A study using thermoelastic stress analysis

Watanabe,

Mishima,

Takehashi

et al. 2024

J. exp. orthop.

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PurposeThermoelastic stress analysis (TSA) was used to evaluate stress changes over the entire surface of a specimen. This study aimed to assess the relationship between femoral stress distribution, analysed using TSA and changes in bone mineral density (BMD) after total hip arthroplasty (THA).MethodsStress changes in the simulated bone before and after taper‐wedge stem insertion were measured using the TSA. Stress changes were compared with BMD changes around the stem 1 year after surgery in a THA patient (58 hips) with the same taper‐wedge stem. Subsequently, we compared the correlation between stress changes and BMD changes.ResultsTSA revealed significant stress changes before and after stem insertion, with prominent alterations in the proximal medial region. The BMD changes at 1 year post‐THA exhibited a 15%–25% decrease in the proximal zones, while Zones 2–6 showed a −6% to 3% change. Notably, a strong positive correlation (0.886) was found between the stress change rate and BMD change rate.ConclusionsThis study demonstrated a high correlation between femoral stress distribution assessed using TSA and subsequent BMD changes after THA. The TSA method offers the potential to predict stress distribution and BMD alterations postsurgery, aiding in implant development and clinical assessment. Combining TSA with finite element analysis could provide even more detailed insights into stress distribution.Level of EvidenceCase series (with or without comparison).

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Primary Stability of Collared and Collarless Cementless Femoral Stems – A Finite Element Analysis Study

Cited by 9 publications

References 25 publications

Radiological Comparison of Canal Fill between Collared and Non-Collared Femoral Stems: A Two-Year Follow-Up after Total Hip Arthroplasty

Radiological Comparison of Canal Fill between Collared and Non-Collared Femoral Stems: A Two-Year Follow-Up after Total Hip Arthroplasty

Does Lack of Initial Collar-Calcar Contact Influence Performance of Collared Cementless Femoral Stems?

Bone mineral density changes around the stem correlate with stress changes after total hip arthroplasty: A study using thermoelastic stress analysis

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