Bone remodeling after total hip arthroplasty using an uncemented anatomic femoral stem: a three-year prospective study using bone densitometry.

Department of Orthopedic Surgery, Miguel Servet University Hospital, Zaragoza, Spain.
Journal of orthopaedic surgery (Hong Kong) (Impact Factor: 0.7). 05/2006; 14(1):32-7.
Source: PubMed


To evaluate the clinical, radiological, and densitometric changes in the bone-remodelling patterns of femoral stems aligned in neutral, valgus, or varus positions.
Between February and October 2000, 70 patients underwent unilateral total hip arthroplasty for primary osteoarthritis using an uncemented Anatomique Benoist Girard (ABG) II stem. 69 patients (30 males and 39 females) with a mean age of 59 years (range, 38-76 years) and a mean body weight of 79.3 kg (range, 29-110 kg) completed 3 years' follow-up on bone remodelling. The clinical, radiological, and densitometric changes of the neutral, valgus, and varus groups were evaluated, and the difference in bone-remodelling patterns between the 3 groups was analysed.
54 patients had neutrally placed stems, while varus and valgus malalignment occurred in 6 and 9 patients, respectively. Clinical and radiological evaluations were very similar among the 3 groups. Only densitometry could detect traceable changes resulting from the differing biomechanics of the neutral, varus, and valgus stem alignments.
The ABG II stem design made moderate errors in alignment biomechanically tolerable. Alignment defects had no clinical consequences and resulted in minimal differences in bone remodelling.

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Available from: Antonio Herrera, Oct 13, 2015
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    • "The results showed that bone loss around the implant is linked to the elastic modulus of the implant; the higher the elastic modulus, the higher the bone loss. In another investigation, Panisello and co-authors evaluated bone-remodeling after unilateral THA in a number of patients [5]. By assessing bone densitometry, they found that stress shielding provoked proximal cortical atrophy. "
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    ABSTRACT: Ti alloys are frequently used in the manufacture of femoral stems for total hip arthroplasty. Although low elastic modulus stems minimize bone stress shielding, they also may produce micromotions at the bone/implant interface, leading to excessive interfacial mechanical stress at the proximal region. This phenomenon may lead to the growth of fibrous tissues and, eventually, implant failure. To address both restrictions simultaneously, stems with adjustable rigidity may be used. Considering that the rigidity of β Ti alloys can be controlled by heat treatments, this paper introduces a new concept for a femoral stem with a graded elastic modulus using metastable β Ti alloy. The combination of solution heat treatment, water-quenching, and aging heat treatments allows the mechanical behavior of the metastable β Ti alloys to be tailored and, in particular, be used to construct a graded elastic modulus femoral hip stem. The results obtained revealed that it is feasible to design biomedical implants from metastable β Ti alloys with hybrid mechanical behavior. The specific mechanical behavior is obtained by focusing only on heat treatments. A stem with an elastic modulus varying from 65 GPa to 110 GPa was obtained.
    Materials and Design 03/2015; 69. DOI:10.1016/j.matdes.2014.11.040 · 3.50 Impact Factor
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    • "hetic bone loss ( Sköldenberg et al . 2006 ) but , on the other hand , stability can be improved by larger stems , thus eliminating distal bone loss seen with smaller ABG II stems ( van der Wal et al . 2006 ) . A larger stem may also help to avoid malalignment of the stem , which appears to cause periprosthetic bone loss in ABG II arthroplasties ( Panisello et al . 2006 ) ."
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    ABSTRACT: Factors that lead to periprosthetic bone loss following total hip arthroplasty (THA) may not only depend on biomechanical implant-related factors, but also on various patient-related factors. We investigated the association between early changes in periprosthetic bone mineral density (BMD) and patient-related factors. 39 female patients underwent cementless THA (ABG II) with ceramic-ceramic bearing surfaces. Periprosthetic BMD in the proximal femur was determined with DXA after surgery and at 3, 6, 12, and 24 months. 27 patient-related factors were analyzed for their value in prediction of periprosthetic bone loss. Total periprosthetic BMD was temporarily reduced by 3.7% at 3 months (p < 0.001), by 3.8% at 6 months (p < 0.01), and by 2.6% at 12 months (p < 0.01), but recovered thereafter up to 24 months. Preoperative systemic osteopenia and osteoporosis, but not the local BMD of the operated hip, was predictive of bone loss in Gruen zone 7 (p = 0.04), which was the only region with a statistically significant decrease in BMD (23%, p < 0.001) at 24 months. Preoperative serum markers of bone turnover predicted the early temporary changes of periprosthetic BMD. The other patient-related factors failed to show any association with the periprosthetic BMD changes. Female patients with low systemic BMD show greater bone loss in Gruen zone 7 after cementless THA than patients with normal BMD. Systemic DXA screening for osteoporosis in postmenopausal patients before THA could be used to identify patients in need of prophylactic anti-resorptive therapy.
    Acta Orthopaedica 10/2009; 80(5):531-7. DOI:10.3109/17453670903316801 · 2.77 Impact Factor
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    • "In our study, all DXA measurements were taken 3 years after THA. Biomechanical adaptation to the prosthesis occurs mainly within 2–3 years, until a BMD plateau stage is reached (Mirsky and Einhorn 1998, Venesmaa et al. 2001, Aldinger et al. 2003, Brodner et al. 2004, Bodén et al. 2006, Panisello et al. 2006). The initial postoperative BMD (Venesmaa et al. 2001) or the preoperative BMD value can be used as the baseline value to estimate the change in "
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    ABSTRACT: Dual-energy X-ray absorptiometry (DXA) analysis of the 7 periprosthetic Gruen zones is the most commonly used protocol to evaluate bone remodeling after the implantation of conventional femoral stems. We assessed the value of DXA after cementless primary total hip arthroplasty (THA) by comparing the effect of progressive shortening of the stem of two femoral implants on periprosthetic bone remodeling using a specifically developed protocol of analysis with 5 periprosthetic regions of interest (ROIs). Bone mineral density (BMD) was evaluated in 37 patients in the plateau stage, 3 years after THA. Two femoral implants featuring conceptually new designs and surgical technique were tested: types 1 and 2, characterized by extremely short stem and virtual absence of distal stem, respectively. We found that progressive shortening of the femoral stem produces more proximal loading, which effectively preserves metaphyseal bone stock and increases periprosthetic BMD in the medial ROIs over time. In the type 2 group, higher absolute BMD values were observed in medial ROIs 4 and 5. No differences were found in ROIs 1, 2, and 3. This study shows the flexibility of DXA in adapting the protocol of periprosthetic analysis to the specific requirements of new implant designs, and it shows its high sensitivity in evaluation of the biological response of bone to changes in implant shape.
    Acta Orthopaedica 02/2009; 80(3):291-7. DOI:10.3109/17453670903074467 · 2.77 Impact Factor
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