Uncemented femoral stem design might have an impact on postoperative periprosthetic femur fracture pattern. A Comparison between flat-wedge and dual-wedge stems

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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K-Wire Technique for the Removal of Uncemented Femoral Stem in Revision THA

Techniques in Orthopaedics ◽

10.1097/bto.0000000000000202 ◽

2017 ◽

Vol 32 (2) ◽

pp. 105-107

Author(s):

Mahmoud A. Hafez

Keyword(s):

Femoral Stem ◽

Revision Tha ◽

Uncemented Femoral Stem

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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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