Alarmingly High Rate of Implant Fractures in One Modular Femoral Stem Design: A Comparison of Two Implants

Objectives: Cemented polished tapered stems have demonstrated excellent long-term outcomes. Based on this concept, many generic tapered stems have been released into the market. The aim of this study was to evaluate implant-related complications of 1 specific stem design. Methods: Between 2010 and 2017, 315 total hip replacements were performed using a Fortress stem (Biotechni, La Ciotat, France). Patient records and radiology were retrospectively reviewed for implant-related complications. A failure analysis was performed on the failed Fortress stems in order to determine the cause of premature failure. Results: 7 (2.2%) patients sustained a fracture of the neck of the implant after a mean of 5 years (range 50–81 months). All fractures were atraumatic, originating at the introducer inlet of the stem. All fractured occurred in obese patients (BMI >33 kg/m2) with a small sized prosthesis. Of these, there were 5 135° and 2 125° stems. Fracture risk was 23% (7/30) for patients with a small sized stem and a BMI >30 kg/m2. All cases were revised using a cement-in-cement technique or a cementless modular revision stem. Failure analysis on the retrieved stems revealed a stress riser at the bottom of the introducer inlet. Conclusions: An alarmingly high rate of early implant fractures was seen using this specific type of cemented stem, particularly when using smaller implant sizes in obese patients. Although based on a proven design, a specific modification led to a stress riser in the neck area, which resulted in a high incidence of implant failure. This series underlines the importance of a stepwise introduction into the market of new orthopaedic devices even when based on established concepts. Generic stems may not behave as the original stem upon which it was designed.

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Massive Pseudotumor in a 28mm Ceramic-Polyethylene Revision THA: A Case Report

Reconstructive Review ◽

10.15438/rr.v4i1.53 ◽

2014 ◽

Vol 4 (1) ◽

pp. 11-17 ◽

Cited By ~ 7

Author(s):

Edward McPherson, M.D., FACS ◽

Matthew Dipane, BA ◽

Sherif Sherif, MD

Keyword(s):

Soft Tissues ◽

Polyethylene Wear ◽

Femoral Stem ◽

High Rate ◽

Zirconia Ceramic ◽

Porous Coating ◽

Metal Debris ◽

Ultrafine Metal Particles ◽

Revision Tha ◽

Therapeutic Study

This report reviews the findings of a massive pseudotumor detected pre-operatively in a 13-year-old revision total hip arthroplasty. The case is unique in that the bearing involved was a 28mm zirconia ceramic head on a polyethylene liner. We propose that the pseudotumor arose from ultrafine titanium particles liberated from the proximal porous coating of the femoral stem. We suspect that the osteolysis produced from polyethylene wear exposed the proximal porous coating and, via a process of mechanical abrasion with the surrounding soft tissues, liberated ultrafine titanium particles. We believe the pseudotumor formed because the patient was pre-sensitized to metal debris based upon a pre-operative lymphocyte T-cell proliferation test (LTT). Based upon this unique case, we feel that pseudotumors more likely form when there is a high rate of ultrafine metal particles generated in a pre-sensitized patient. Finally, we introduce what we believe are the main biologic wear responses in THA. Further research is needed to validate this proposed model.Keywords: pseudotumor, ceramic, polyethylene, osteolysis, THA, bearing wear eesponse, titanium debrisLevel of Evidence: AAOS Therapeutic Study Level IV

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Displacement of Femoral Stem during Closed Reduction of Total Hip Arthroplasty

Hip International ◽

10.1177/112070009700700302 ◽

1997 ◽

Vol 7 (3) ◽

pp. 125-127

Author(s):

J. Cordes ◽

K. Sperling ◽

M. Kramhøft

Keyword(s):

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Closed Reduction ◽

Femoral Stem ◽

Stem Design ◽

Total Hip ◽

Straight Stem ◽

Image Intensification

In the literature, only one case of displacement of a cemented femoral stem from its cement bed during closed reduction of a dislocation has been reported. In that case, it was suggested that the stem design may in part be the explanation for the displacement. Another case with a cemented Müller straight stem is now presented, emphasizing the use of image intensification if reduction proves difficult.

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Current methods of preventing aseptic loosening and improving osseointegration of titanium implants in cementless total hip arthroplasty: a review

Journal of International Medical Research ◽

10.1177/0300060517732697 ◽

2017 ◽

Vol 46 (6) ◽

pp. 2104-2119 ◽

Cited By ~ 32

Author(s):

Dragos Apostu ◽

Ondine Lucaciu ◽

Cristian Berce ◽

Dan Lucaciu ◽

Dan Cosma

Keyword(s):

Aseptic Loosening ◽

Hip Arthroplasty ◽

Psychotic Disorders ◽

Femoral Stem ◽

Hip Osteoarthritis ◽

Titanium Implants ◽

Good Survival ◽

Acetabular Cup ◽

Implant Surface ◽

Stem Design

Hip osteoarthritis is the most common joint disorder, and is represented by a degenerative process, resulting in pain and functional impairment. If conservative treatment for hip osteoarthritis fails, the only remaining option is hip arthroplasty. Despite good survival of implants, loosening of components is the most common complication. This leads to revision surgeries, which are technically demanding, expensive, and result in a low satisfaction rate. Uncemented hip replacements require proper osseointegration for increased survival. Physical characteristics of implants include biocompatibility, Young’s modulus of elasticity, strength, and corrosion resistance, and each influence fixation of implants. Moreover, implant surface treatments, pore size, pore density, and femoral stem design should be appropriately selected. Patients’ optimization of obesity, osteoporosis, cardiovascular disease, psychotic disorders, and smoking cessation are associated with a higher survival of implants. Surgical factors, such as approach, drilling and rasping, acetabular bone coverage, acetabular cup positioning, and implant size, also affect survival of implants. Avoiding drugs, which may impair osseointegration of implants, and having an appropriate rehabilitation protocol are important. Future directions include anabolic and anti-catabolic bone-acting drugs to enhance osseointegration of implants. Comprehensive knowledge of the factors mentioned above is important for preventing aseptic loosening, with important socioeconomic consequences.

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Prospective clinical study using radiostereometric analysis (RSA) to evaluate fixation of a modular cemented polished femoral stem

Hip International ◽

10.1177/1120700019881429 ◽

2019 ◽

pp. 112070001988142

Author(s):

C Glen Richardson ◽

Elise K Laende ◽

Michael Gross ◽

Michael J Dunbar

Keyword(s):

Clinical Success ◽

Femoral Stem ◽

Prospective Clinical Study ◽

Radiostereometric Analysis ◽

Stem Design ◽

Modular Stem ◽

Long Term Follow Up ◽

Post Operation ◽

Design Type

Background: The long-term clinical success of cemented polished tapered femoral components has been demonstrated in prospective as well as registry studies. This stem design type has also been well studied with radiostereometric analysis (RSA) and provides a standard to evaluate alternative designs of polished tapered cemented femoral components. This prospective study evaluates the subsidence of a polished cemented stem with a modular neck design utilising RSA. Methods: 26 patients were prospectively enrolled in the study and 23 were available for RSA analysis at 2 years. Results: The average subsidence of the femoral implant was 1.1 mm (SD 0.4 mm) at 2 years post operation. There were no revisions in this group, specifically no failures of the modular stem-neck design as has been seen with other implants. Conclusions: The RSA subsidence pattern at 2 years of this cemented femoral stem is similar to other successful designs with long-term follow-up. The implications over time of stem neck modularity for cemented polished tapered femoral components requires further evaluation.

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Impact of stem design and cementation on postoperative femoral antetorsion in 227 patients with total hip arthroplasty (THA)

Skeletal Radiology ◽

10.1007/s00256-020-03483-z ◽

2020 ◽

Vol 49 (12) ◽

pp. 2001-2009

Author(s):

Tim Fischer ◽

Christoph Stern ◽

Benjamin Fritz ◽

Patrick O. Zingg ◽

Christian W. A. Pfirrmann ◽

...

Keyword(s):

Retrospective Study ◽

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Hip Prosthesis ◽

Femoral Stem ◽

Stem Design ◽

Femoral Antetorsion ◽

Total Hip ◽

Posterior Condylar ◽

Lower Variability

Abstract Objective In total hip arthroplasty (THA), surgeons attempt to achieve a physiological antetorsion. However, postoperative antetorsion of the femoral stem is known to show large variabilities. The purpose of this study was to assess whether postoperative antetorsion is influenced by stem design or cementation. Materials and methods This retrospective study included 227 patients with a hip prosthesis with five different stem designs (S1: short curved, S2 and S3: standard straight, S4: standard straight collared, S5: cemented straight), who had metal suppressed 1.5T-MRI of the hip between February 2015 and October 2019. Measurement of femoral antetorsion was done independently by two fellowship-trained radiologists on axial images by measuring the angle between the long axis of the femoral neck and the posterior condylar tangent of the knee. Measured angles in the different groups were compared using the t test for independent samples. Results The cementless collared stem S4 showed the highest antetorsion with 18.1° (± 10.5°; range –10°–45°), which was significantly higher than the antetorsion of the collarless S3 with 13.3° (± 8.4°; − 4°–29°) and the cemented S5 with 12.7° (± 7.7°; − 3°–27°) with p = 0.012 and p = 0.007, respectively. S1 and S2 showed an antetorsion of 14.8° (± 10.0°; 1°–37°) and 14.1° (± 12.2°; − 20°–41°). The torsional variability of the cementless stems (S1–4) was significantly higher compared with that of the cemented S5 with a combined standard deviation of 10.5° and 7.7° (p = 0.019). Conclusion Prosthesis design impacts the postoperative femoral antetorsion, with the cementless collared stem showing the highest antetorsion. Cemented stems demonstrated significantly lower variability, suggesting the lowest rate of inadvertent malrotation.

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Model-Based Roentgen Stereophotogrammetric Analysis Using Elementary Geometrical Shape Models: Reliability of Migration Measurements for an Anatomically Shaped Femoral Stem Component

Applied Sciences ◽

10.3390/app10238507 ◽

2020 ◽

Vol 10 (23) ◽

pp. 8507

Author(s):

Jing Xu ◽

Han Cao ◽

Stefan Sesselmann ◽

Dominic Taylor ◽

Raimund Forst ◽

...

Keyword(s):

Femoral Stem ◽

Geometrical Shape ◽

Stem Design ◽

Rater Reliability ◽

Roentgen Stereophotogrammetric Analysis ◽

Model Based ◽

Alternative Approach ◽

Out Of Plane ◽

Rater Variability

Elementary Geometrical Shape (EGS) models present an alternative approach to detect in vivo migration of total hip arthroplasty using model-based Roentgen Stereophotogrammetric Analysis (mbRSA). However, its applicability for an irregular-shaped femoral stem and the reliability of this mbRSA approach has not been proven so far. The aim of this study is to assess the effect of multi-rater and an anatomically shaped femoral stem design onto resulting implant to bone migration results. The retrospective analysis included 18 clinical cases of anatomically shaped stem with 10-year RSA follow-ups. Three raters repeatedly measured all RSA follow-ups for evaluating the rater equivalence and intra-rater reliability. The results proved the equivalence between different raters for mbRSA using EGS models (mbRSA-EGS), hence it simplified the investigation of rater reliability to intra-rater reliability. In all in-plane migration measurements, mbRSA-EGS shows good intra-rater reliability and small intra-rater variability (translation: <0.15 mm; rotation: <0.18 deg). However, the reliability is worse in the out-of-plane measurements, especially the cranial-caudal rotation (intra-rater variability: 0.99–1.81 deg). Overall, mbRSA-EGS can be an alternative approach next to surface models while the in-plane migration of femoral stem (e.g., the implant subsidence for loosening prediction) have more research interested than other directions.

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Fixation of the Cemented Stem: Clinical Relevance of the Porosity and Thickness of the Cement Mantle

The Open Orthopaedics Journal ◽

10.2174/1874325000903010008 ◽

2009 ◽

Vol 3 (1) ◽

pp. 8-13 ◽

Cited By ~ 3

Author(s):

Philippe Hernigou ◽

Gildasio Daltro ◽

Charles Henri Flouzat Lachaniette ◽

Xavier Roussignol ◽

Martin Mukisi Mukasa ◽

...

Keyword(s):

Hip Arthroplasty ◽

Review Paper ◽

Mechanical Stability ◽

Femoral Stem ◽

Clinical Results ◽

Cement Mantle ◽

Frictional Torque ◽

Stem Design ◽

Cement Interface ◽

Cemented Stem

The aim of this review paper is to define the fixation of the cemented stem. Polymethyl methacrylate, otherwise known as “bone cement”, has been used in the fixation of hip implants since the early 1960s. Sir John Charnley, the pioneer of modern hip replacement, incorporated the use of cement in the development of low frictional torque hip arthroplasty. In this paper, the concepts of femoral stem design and fixation, clinical results, and advances in understanding of the optimal use of cement are reviewed. The purpose of this paper is to help understanding and discussions on the thickness and the porosity of the cement mantle in total hip arthroplasty. Cement does not act as an adhesive, as sometimes thought, but relies on an interlocking fit to provide mechanical stability at the cement–bone interface, while at the prosthesis– cement interface it achieves stability by optimizing the fit of the implant in the cement mantle, such as in a tapered femoral stem.

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