Radiological Evaluation of the Relationship Between Cortical Hypertrophy and Stress Shielding After Total Hip Arthroplasty Using a Cementless Stem

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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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

10.21203/rs.3.rs-736895/v1 ◽

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.

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The Wagner SL-Revision Stem for Aseptic Loosening: Clinical and Radiological Results 5 to 7 Years after Femoral Revision

Hip International ◽

10.1177/112070000301300206 ◽

2003 ◽

Vol 13 (2) ◽

pp. 94-100

Author(s):

M.J.F. Diks ◽

M. Spruit ◽

J.J. Reimering ◽

F. Den Boer ◽

P.G. Anderson

Keyword(s):

Total Hip Arthroplasty ◽

Bone Loss ◽

Aseptic Loosening ◽

Hip Arthroplasty ◽

Primary Stability ◽

Harris Hip Score ◽

Radiological Evaluation ◽

Total Hip ◽

Revision Stem

Aseptic loosening in total hip arthroplasty can lead to proximal femoral periprosthetic bone loss. The non-cemented Wagner revision stem achieves primary fixation in the diaphysis. The purpose of this study is to evaluate the results after medium- to long-term follow-up of the Wagner prosthesis for revision of the femoral component for aseptic loosening in total hip arthroplasty with proximal femoral bone loss. We performed 53 femoral revisions for aseptic loosening with the non-cemented Wagner revision stem. Clinical assessment included a modified Harris Hip Score and a radiological evaluation. The mean follow-up was 65 months. The Harris Hip Score improved significantly (42.9 to 72.3). Radiological evaluation revealed 24.5% subsidence (>5 mm) in our population. Nine re-revisions were done, eight in the first post-operative year. The re-revisions were performed for progressive subsidence (five), recurrent dislocations (one), subsidence with low-grade infection (one), false route (one), and aseptic loosening after 75 months (one). The cumulative survival rate of the Wagner stem after 12 months was 85% and 76% after 75 months. A relatively high re-revision rate was observed during the first post-operative year. Analysis of these failures has shown that subsidence may be the result of insufficient primary stability. Adequate pre-operative planning and intra-operative radiological assistance is necessary for perfect primary stability and fixation of the Wagner stem. The re-revision incidence after the first 12 months is 0.45 per 100 implants per year. The prosthesis has good survival potential after proper introduction.

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An Analysis of the Relationship Between the Utilization of Physical Therapy Services and Outcomes of Care for Patients After Total Hip Arthroplasty

Physical Therapy ◽

10.1093/ptj/80.5.448 ◽

2000 ◽

Vol 80 (5) ◽

pp. 448-458 ◽

Cited By ~ 48

Author(s):

Janet K Freburger

Keyword(s):

Physical Therapy ◽

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Cost Of Care ◽

Total Cost ◽

Total Hip ◽

Outcomes Of Care ◽

The Relationship ◽

Therapy Intervention ◽

Physical Therapy Intervention

Abstract Background and Purpose. The effect of physical therapy intervention on the outcomes of care for patients treated in acute care hospitals has not been widely studied. This study examined the relationship between physical therapy utilization and outcomes of care for patients following total hip arthroplasty. Subjects. The sample consisted of 7,495 patients treated in US academic health center hospitals in 1996 who survived their inpatient stay and received physical therapy interventions. Methods. The primary data source was the University HealthSystem Consortium Clinical Data Base. Physical therapy use was assessed by examining physical therapy charges. Outcomes of care were assessed in terms of the total cost of care (ie, whether the care was more costly or less costly than expected, taking into account patient characteristics) and in terms of discharge destination (ie, whether the patient was discharged home or elsewhere). Regression analyses were conducted to examine the relationship between physical therapy use and outcomes. Results. Physical therapy intervention was directly related to a total cost of care that was less than expected and to an increased probability of discharge home. Conclusion and Discussion. The results of this study provide preliminary evidence to support the use of physical therapy intervention in the acute care of patients following total hip arthroplasty and indicate the need for further study of this topic.

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