scholarly journals Minimal stress shielding with a Mallory-Head titanium femoral stem with proximal porous coating in total hip arthroplasty

2009 ◽  
Vol 4 (1) ◽  
Author(s):  
Brad Ellison ◽  
Nicholas A Cheney ◽  
Keith R Berend ◽  
Adolph V Lombardi ◽  
Thomas H Mallory
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Stress Shielding ◽  
Femoral Stem ◽  
Porous Coating ◽  
Total Hip ◽  
Minimal Stress

scholarly journals Fully porous 3D printed titanium femoral stem to reduce stress-shielding following total hip arthroplasty

2016 ◽  
Vol 35 (8) ◽  
pp. 1774-1783 ◽  
Author(s):  
Sajad Arabnejad ◽  
Burnett Johnston ◽  
Michael Tanzer ◽  
Damiano Pasini
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Stress Shielding ◽  
Femoral Stem ◽  
Total Hip ◽  
3D Printed

scholarly journals Total Hip Arthroplasty Using Proximal Porous Coating Stem with Distal Sleeve: Mid-Term Outcome

2009 ◽  
Vol 17 (1) ◽  
pp. 36-41 ◽  
Author(s):  
M Saito ◽  
KA Takahashi ◽  
M Fujioka ◽  
K Ueshima ◽  
K Sakao ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Japanese Orthopaedic Association ◽  
Stress Shielding ◽  
Porous Coating ◽  
Occupancy Rate ◽  
Term Outcome ◽  
Total Hip ◽  
Radiolucent Lines ◽  
Bone Changes

Purpose. To report mid-term results of total hip arthroplasty (THA) using the Opti-Fix Plus Hip System (Opti-Fix Hip), and to assess the correlations between peri-implant bone changes and the distal medullary occupancy rate. Methods. 11 men (13 hips) and 53 women (58 hips) aged 24 to 87 (mean, 61) years underwent THA using the Opti-Fix Hip, with a modular stem and a distal sleeve, and were followed up for a mean of 6.5 (range, 4.8–9.6) years. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) hip score. Implant stability, bone changes around the implant, and the occupancy rate of the stem in the medullary space were examined radiologically. Bone changes around the implant were assessed based on the radiological evidence of a pedestal, osteolysis, stress shielding, and radiolucent lines. Results. The mean JOA score increased significantly after surgery and was maintained at the latest follow-up. Around the acetabular and femoral components respectively, 38 and 58 hips had radiolucent lines, whereas one and 54 hips developed osteolysis. A pedestal appeared in 21 hips and grade-III or higher stress shielding in 30 hips. Two hips showed loosening of the acetabular components, but none in the femoral components. Osteolysis around the stem was frequently observed in hips with poor distal medullary occupancy. Conclusion. Clinical and radiological outcomes of the Opti-Fix Hip were favourable. The low incidence of osteolysis in the distal stem suggests that the proximal circumferential porous coating was effective. Minor osteolysis around the proximal stem was frequently observed, indicating early excessive wear of the polyethylene liner. Its high distal medullary occupancy rate could inhibit stem micromotion and aseptic loosening.

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.

scholarly journals Value of 3D Preoperative Planning for Primary Total Hip Arthroplasty Based on Biplanar Weightbearing Radiographs

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Y. Knafo ◽  
F. Houfani ◽  
B. Zaharia ◽  
F. Egrise ◽  
I. Clerc-Urmès ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Preoperative Planning ◽  
Femoral Stem ◽  
Leg Length ◽  
Femoral Offset ◽  
Postoperative Result ◽  
Total Hip ◽  
Planning Software ◽  
Navigated Surgery

Two-dimensional (2D) planning on standard radiographs for total hip arthroplasty may not be sufficiently accurate to predict implant sizing or restore leg length and femoral offset, whereas 3D planning avoids magnification and projection errors. Furthermore, weightbearing measures are not available with computed tomography (CT) and leg length and offset are rarely checked postoperatively using any imaging modality. Navigation can usually achieve a surgical plan precisely, but the choice of that plan remains key, which is best guided by preoperative planning. The study objectives were therefore to (1) evaluate the accuracy of stem/cup size prediction using dedicated 3D planning software based on biplanar radiographic imaging under weightbearing and (2) compare the preplanned leg length and femoral offset with the postoperative result. This single-centre, single-surgeon prospective study consisted of a cohort of 33 patients operated on over 24 months. The routine clinical workflow consisted of preoperative biplanar weightbearing imaging, 3D surgical planning, navigated surgery to execute the plan, and postoperative biplanar imaging to verify the radiological outcomes in 3D weightbearing. 3D planning was performed with the dedicated hipEOS® planning software to determine stem and cup size and position, plus 3D anatomical and functional parameters, in particular variations in leg length and femoral offset. Component size planning accuracy was 94% (31/33) within one size for the femoral stem and 100% (33/33) within one size for the acetabular cup. There were no significant differences between planned versus implanted femoral stem size or planned versus measured changes in leg length or offset. Cup size did differ significantly, tending towards implanting one size larger when there was a difference. Biplanar radiographs plus hipEOS planning software showed good reliability for predicting implant size, leg length, and femoral offset and postoperatively provided a check on the navigated surgery. Compared to previous studies, the predictive results were better than 2D planning on conventional radiography and equal to 3D planning on CT images, with lower radiation dose, and in the weightbearing position.

scholarly journals The impact of reducing the femoral stem length in total hip arthroplasty during gait

2021 ◽  
Author(s):  
Anatole Vilhelm Wiik ◽  
Adeel Aqil ◽  
Bilal Al-Obaidi ◽  
Mads Brevadt ◽  
Justin Peter Cobb
Keyword(s):  
Total Hip Arthroplasty ◽  
Gait Analysis ◽  
Hip Arthroplasty ◽  
Femoral Stem ◽  
Short Stem ◽  
Stem Length ◽  
Practical Consideration ◽  
Total Hip ◽  
Long Stem ◽  
The Impact

Abstract Aim The length of the femoral stem in total hip arthroplasty (THA) is a practical consideration to prevent gait impairment. The aim of this study was to determine if reducing the femoral stem length in THA would lead to impaired gait biomechanics. Methods Patients uniformly with the same brand implant of differing lengths (100 mm vs 140–166 mm) were taken retrospectively from a prospective trial introducing a new short stem. Twelve patients without any other disorder to alter gait besides contralateral differing length stem THA were tested at differing gradients and speed on a validated instrumented treadmill measuring ground reaction forces. An anthropometrically similar group of healthy controls were analysed to compare. Results With the same posterior surgical approach, the offset and length of both hips were reconstructed within 5 mm of each other with an identical mean head size of 36 mm. The short stem was the last procedure for all the hips with gait analysis occurring at a mean of 31 and 79 months postoperatively for the short and long stem THA, respectively. Gait analysis between limbs of both stem lengths demonstrated no statistical difference during any walking condition. In the 90 gait assessments with three loading variables, the short stem was the favoured side 51% of the time compared 49% for the long stem. Conclusion By testing a range of practical walking activities, no lower limb loading differences can be observed by reducing the femoral stem length. A shorter stem demonstrates equivalence in preference during gait when compared to a reputable conventional stem in total hip arthroplasty.

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.

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