scholarly journals Application Of A Thermodynamic-Based Model To Investigate Bone Remodeling After Total Hip Arthroplasty Using Different Hip Implants

2021 ◽  
Author(s):  
Alireza Sayyidmousavi
Keyword(s):  
Total Hip Arthroplasty ◽  
Bone Remodeling ◽  
Mechanical Loading ◽  
Hip Arthroplasty ◽  
Stress Shielding ◽  
Irreversible Thermodynamics ◽  
Total Hip ◽  
Finite Element Software ◽  
Custom Made ◽  
Hip Stems

A new thermodynamic-based model for bone remodeling is introduced. This model is based on chemical kinetics and irreversible thermodynamics in which bone is treated as a self-organizing system capable of exchanging matter, energy and entropy with its surroundings. Unlike the previous works in which mechanical loading is regarded as the only stimulus for bone remodeling, this model establishes a coupling between mechanical loading and the chemical reactions involved in the process of bone remodeling. This model is then incorporated to the finite element software ANSYS in the form of a macro to study bone remodeling after total hip arthroplasty with four different implants: Custom-made titanium, composite, Exceter and Omnifit hip stems. Numerical computations of bone density distribution after total hip arthroplasty indicate that the Omnifit implant with carbon fiber polyamide 12 composite results in minimum resorption in the proximal femur and consequently minimum bone loss due to stress shielding.

scholarly journals Application Of A Thermodynamic-Based Model To Investigate Bone Remodeling After Total Hip Arthroplasty Using Different Hip Implants

2021 ◽  
Author(s):  
Alireza Sayyidmousavi
Keyword(s):  
Total Hip Arthroplasty ◽  
Bone Remodeling ◽  
Mechanical Loading ◽  
Hip Arthroplasty ◽  
Stress Shielding ◽  
Irreversible Thermodynamics ◽  
Total Hip ◽  
Finite Element Software ◽  
Custom Made ◽  
Hip Stems

A new thermodynamic-based model for bone remodeling is introduced. This model is based on chemical kinetics and irreversible thermodynamics in which bone is treated as a self-organizing system capable of exchanging matter, energy and entropy with its surroundings. Unlike the previous works in which mechanical loading is regarded as the only stimulus for bone remodeling, this model establishes a coupling between mechanical loading and the chemical reactions involved in the process of bone remodeling. This model is then incorporated to the finite element software ANSYS in the form of a macro to study bone remodeling after total hip arthroplasty with four different implants: Custom-made titanium, composite, Exceter and Omnifit hip stems. Numerical computations of bone density distribution after total hip arthroplasty indicate that the Omnifit implant with carbon fiber polyamide 12 composite results in minimum resorption in the proximal femur and consequently minimum bone loss due to stress shielding.

scholarly journals Microsection analysis of cortical form-fit of a custom femoral component in total hip arthroplasty: an in vitro study

2012 ◽  
Vol 4 (3) ◽  
pp. 31 ◽  
Author(s):  
Ulf Gunther Leichtle ◽  
Carmen Ina Leichtle ◽  
Franz Martini
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Stress Shielding ◽  
Femoral Stem ◽  
In Vitro Study ◽  
Limited Information ◽  
Total Hip ◽  
Custom Made ◽  
Diamond Saw

Custom femoral components have been developed for total hip arthroplasty to maximize cortical form-fit and thereby to reduce the problems of stress shielding and aseptic loosening. Limited information is available about how much endosteal cortical contact can actually be achieved with these expensive implants. The aim of this study was therefore to verify the exact cortical contact of a custom made stem using microsections and comparing it to a standard stem with similar design. In 8 human femurs (3 matched pairs and 2 separate specimens), custom femoral prostheses (Adaptiva; 5 femurs: 3 matched and 2 separate) and conventional femoral prostheses (Alloclassic; 3 matched femurs) were implanted. Endosteal cortical contact was determined from CAD planning drafts and microsections cut from the specimens with a diamond saw. Microsection analysis of the paired femurs showed that contact between prosthesis and bone varied clearly along the length of the femoral stem. Total cortical contact was con- siderably greater in custom prostheses than conventional prostheses (custom, 47%; conventional, 32%), but markedly less than the total contact predicted by the manufacturer (84% to 90%). The custom prosthesis had more lateral cortical contact on CAD planning drafts (cortical contact: medial, 60%; lateral, 53%) than on specimen microsections after implantation (medial, 64%; lateral, 24%). In summary, the philosophy of anchorage of both prostheses types could be confirmed. However, areas of cortical contact of the custom made prosthesis were considerably smaller compared to the pre-operative planning.

Custom-Made Femoral Implants in Total HIP Arthroplasty Due to Congenital Disease of the HIP: A Review

2016 ◽  
Vol 26 (3) ◽  
pp. 209-214 ◽  
Author(s):  
Dimitrios T. Tsiampas ◽  
Emilios E. Pakos ◽  
Georgios C. Georgiadis ◽  
Theodoros A. Xenakis
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Congenital Disease ◽  
Total Hip ◽  
Custom Made ◽  
Femoral Implants

Redesign of the Femoral Stem for a Total Hip Arthroplasty for Additive Manufacturing

2018 ◽  
Author(s):  
Bradley Hanks ◽  
Shantanab Dinda ◽  
Sanjay Joshi
Keyword(s):  
Additive Manufacturing ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Lattice Structure ◽  
Stress Shielding ◽  
Patient Specific ◽  
Hip Implants ◽  
Hip Implant ◽  
Total Hip ◽  
Multiple Materials

Total hip arthroplasty (THA) is an increasingly common procedure that replaces all or part of the hip joint. The average age of patients is decreasing, which in turn increases the need for more durable implants. Revisions in hip implants are frequently caused by three primary issues: femoral loading, poor fixation, and stress shielding. First, as the age of hip implant patients decreases, the hip implants are seeing increased loading, beyond what they were traditionally designed for. Second, traditional implants may have roughened surfaces but are not fully porous which would allow bone to grow in and through the implant. Third, traditional implants are too stiff, causing more load to be carried by the implant and shielding the bone from stress. Ultimately this stress shielding leads to bone resorption and implant loosening. Additive manufacturing (AM) presents a unique opportunity for enhanced performance by allowing for personalized medicine and increased functionality through geometrically complex parts. Much research has been devoted to how AM can be used to improve surgical implants through lattice structures. To date, the authors have found no studies that have performed a complete 3D lattice structure optimization in patient specific anatomy. This paper discusses the general design of an AM hip implant that is personalized for patient specific anatomy and proposes a workflow for optimizing a lattice structure within the implant. Using this design workflow, several lattice structured AM hip implants of various unit cell types are optimized. A solid hip implant is compared against the optimized hip implants. It appears the AM hip implant with a tetra lattice outperforms the other implant by reducing stiffness and allowing for greater bone ingrowth. Ultimately it was found that AM software still has many limitations associated with attempting complex optimizations with multiple materials in patient specific anatomy. Though software limitations prevented a full 3D optimization in patient specific anatomy, the challenges associated such an approach and limitations of the current software are discussed.

scholarly journals Preventing Loss of Femoral Periprosthetic Bone Mineral Density in Cementless Total Hip Arthroplasty Using a Tapered Wedge Stem in Patients With Osteoporosis Treated With Denosumab: a Retrospective, Cohort Study

2021 ◽  
Author(s):  
Keiji Kamo ◽  
Hiroaki Kijima ◽  
Koichiro Okuyama ◽  
Tetsuya Kawano ◽  
Nobutoshi Seki ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Total Hip Arthroplasty ◽  
Bone Mineral ◽  
Hip Arthroplasty ◽  
Stress Shielding ◽  
Control Group ◽  
Mineral Density ◽  
Total Hip ◽  
Cementless Total Hip Arthroplasty ◽  
Periprosthetic Bone Mineral Density

Abstract Background: Bone mineral density (BMD) of the proximal femur around the stem decreases due to stress shielding after cementless total hip arthroplasty (THA). When severe stress shielding occurs, the risk of periprosthetic femoral fractures increases, and this bone loss can also increase the difficulty of future revision THA. Denosumab is known to improve the quality and strength of cortical bone in the proximal femurs of patients with osteoporosis. The purpose of this study was to investigate whether denosumab prevents loss of proximal femoral periprosthetic BMD in cementless THA using a tapered wedge stem in patients with osteoporosis.Methods: Sixty-three consecutive patients who had undergone unilateral primary THA using a tapered wedge stem were included in this retrospective study. Twenty-four patients who received denosumab for osteoporosis were the denosumab group, and the 39 without denosumab were the control group. At 2 weeks, 6 months, and 12 months after THA, bone turnover markers and femoral periprosthetic BMD were measured.Results: BMD in zone 1 was significantly increased from baseline at both 6 and 12 months after THA in the denosumab group and significantly decreased in the control group. BMD in zone 7 was significantly decreased compared to baseline at both 6 and 12 months after THA in the control group, but not in the denosumab group. The use of denosumab for THA patients with osteoporosis was independently related to preventing loss of periprosthetic BMD of the femur at 12 months after surgery in zones 1 and 7 on multivariate analysis.Conclusions: Denosumab significantly increased proximal femoral periprosthetic BMD in zone 1 and prevented loss of BMD in zone 7 in patients with osteoporosis after cementless THA using a tapered wedge stem at both 6 and 12 months after surgery.

Evaluation of Periprosthetic Bone-Remodeling After Cementless Total Hip Arthroplasty

2000 ◽  
Vol 82 (10) ◽  
pp. 1426-1431 ◽  
Author(s):  
KATSUYUKI YAMAGUCHI ◽  
KENSAKU MASUHARA ◽  
KENJI OHZONO ◽  
NOBUHIKO SUGANO ◽  
TAKASHI NISHII ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Bone Remodeling ◽  
Hip Arthroplasty ◽  
Periprosthetic Bone ◽  
Total Hip ◽  
Cementless Total Hip Arthroplasty

Early to medium-term outcomes of uncemented ceramic-bearing total hip arthroplasty in teenagers for paediatric hip conditions

2020 ◽  
Vol 102-B (11) ◽  
pp. 1491-1496
Author(s):  
Pranai K. Buddhdev ◽  
Ivor S. Vanhegan ◽  
Tahir Khan ◽  
Aresh Hashemi-Nejad
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Femoral Stem ◽  
Adolescent And Young Adult ◽  
Medium Term ◽  
Total Hip ◽  
Custom Made ◽  
The Mean ◽  
Custom Made Prostheses

Aims Despite advances in the treatment of paediatric hip disease, adolescent and young adult patients can develop early onset end-stage osteoarthritis. The aims of this study were to address the indications and medium-term outcomes for total hip arthroplasty (THA) with ceramic bearings for teenage patients. Methods Surgery was performed by a single surgeon working in the paediatric orthopaedic unit of a tertiary referral hospital. Databases were interrogated from 2003 to 2017 for all teenage patients undergoing THA with a minimum 2.3 year follow-up. Data capture included patient demographics, the underlying hip pathology, number of previous surgeries, and THA prostheses used. Institutional ethical approval was granted to contact patients for prospective clinical outcomes and obtain up-to-date radiographs. In total, 60 primary hips were implanted in 51 patients (35 female, 16 male) with nine bilateral cases. The mean age was 16.7 years (12 to 19) and mean follow-up was 9.3 years (2.3 to 16.8). Results The most common indication for teenage hip arthroplasty was avascular necrosis secondary to slipped upper femoral epiphysis (31%; n = 16). Overall, 64% of patients (n = 33) had undergone multiple previous operations. The survival at follow-up was 97%; two patients required revision for aseptic loosening (one femoral stem, one acetabular component). Both patients had fused hips noted at the time of arthroplasty. A further two patients had radiolucent lines but were asymptomatic. At latest follow-up the mean Oxford Hip Score was 44 (31 to 48) and a Visual Analogue Scale measurement of 1.5, indicating satisfactory function. Conclusion Operating on this cohort can be complicated by multiple previous surgeries and distorted anatomy, which in some cases require custom-made prostheses. We have demonstrated a good outcome with low revision rate in this complex group of patients. Cite this article: Bone Joint J 2020;102-B(11):1491–1496.

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