Periprosthetic Bone Remodeling after 12 Years Differs in Cemented and Uncemented Hip Arthroplasties

Trauma and Orthopaedics, Scarborough General Hospital, Scarborough, West Yorkshire, UK.
Clinical Orthopaedics and Related Research (Impact Factor: 2.77). 10/2011; 470(5):1431-5. DOI: 10.1007/s11999-011-2134-1
Source: PubMed


Different patterns of stress shielding may lead to differences in periprosthetic bone preservation around cemented and uncemented hips in the long term?
The purpose of this study is to compare the difference in periprosthetic bone density between cemented Charnley total hip and uncemented hydroxyapatite-coated Furlong THAs at a minimum followup of 12 years (mean, 16 years; range, 12-24 years).
We studied a cohort of 17 patients who had bilateral THAs with a cemented Charnley THA on one side and an uncemented Furlong hydroxyapatite-coated THA on the other side. At a minimum followup of 12 years, Harris and Oxford hip scores were used to determine the function, and dual-energy x-ray absorptiometry was used to quantify bone mineral density adjacent to the prosthesis. The results of the dual-energy x-ray absorptiometry scan for cemented and uncemented hips were analyzed using paired-sample two-tailed t-tests. To compare the Harris hip scores, a nonparametric Wilcoxon test was used.
Bone mineral density was higher on the uncemented Furlong side in Gruen Zones 2, 3, 5, and 6 of the proximal femur and DeLee and Charnley Zone 1 of the acetabulum. In all other zones, there was no difference. Comparison of Harris and Oxford hip scores showed no differences between the two hips.
Bone density is better preserved around the uncemented hydroxyapatite-coated Furlong stem compared with the Charnley cemented stem.
Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

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Available from: Mark Andrews, Jan 22, 2014
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    • "In total hip replacement (THR), implantation of the proximal femur with a stiff metal femoral stem to support an artificial bearing is recognised to produce proximal load bypass and distal load increase (Bobyn et al 1992). This corresponds with loss of proximal trabecular bone mineral density (BMD) and cortical thickness (Brodner et al 2004; Chandran et al 2012; Stucinskas et al 2012; Jayasuriya et al 2013), distal cortical thickening (Abadie et al 2010), and in cementless implants the formation of trabecular pedestal features (Slack et al 2006). In resurfacing hip replacement (RHR), replacement of the femoral articular cartilage and a layer of supporting bone with a stiff metal shell leads to cancellous bone resorption inside the femoral head and a narrowing of the femoral neck at its junction with the head. "
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    ABSTRACT: Bone morphology and density changes are commonly observed following joint replacement, may contribute to the risks of implant loosening and periprosthetic fracture and reduce the available bone stock for revision surgery. This study was presented in the 'Bone and Cartilage Mechanobiology across the scales' WCCM symposium to review the development of remodelling prediction methods and to demonstrate simulation of adaptive bone remodelling around hip replacement femoral components, incorporating intrinsic (prosthesis) and extrinsic (activity and loading) factors. An iterative bone remodelling process was applied to finite element models of a femur implanted with a cementless total hip replacement (THR) and a hip resurfacing implant. Previously developed for a cemented THR implant, this modified process enabled the influence of pre- to post-operative changes in patient activity and joint loading to be evaluated. A control algorithm used identical pre- and post-operative conditions, and the predicted extents and temporal trends of remodelling were measured by generating virtual X-rays and DXA scans. The modified process improved qualitative and quantitative remodelling predictions for both the cementless THR and resurfacing implants, but demonstrated the sensitivity to DXA scan region definition and appropriate implant-bone position and sizing. Predicted remodelling in the intact femur in response to changed activity and loading demonstrated that in this simplified model, although the influence of the extrinsic effects were important, the mechanics of implantation were dominant. This study supports the application of predictive bone remodelling as one element in the range of physical and computational studies, which should be conducted in the preclinical evaluation of new prostheses.
    Full-text · Article · Jul 2015 · Biomechanics and Modeling in Mechanobiology
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    ABSTRACT: BACKGROUND: There are two unusual remodeling patterns of the proximal femur around well-fixed Charnley total hip arthroplasties: cortical thinning leading to endosteal widening around the femoral component and hypertrophy of the distal femoral cortex. Previous studies have shown remodeling patterns are affected by stem design and occur early postoperatively. It is unclear if these changes are related to patient demographics or if they progress throughout the lifetime of the implant. QUESTIONS/PURPOSES: We determined if patient demographic variables influence remodeling patterns after cemented Charnley total hip arthroplasty and if the observed remodeling changes persist long-term. METHODS: We retrospectively reviewed the radiographs of 106 well-fixed Charnley femoral components. Using a novel digital edge detection program, we determined the femoral remodeling pattern and time-related changes in femoral dimensions. The minimum followup was 20 years (mean, 25.3 years; range, 19.5-37 years). RESULTS: We found no association between remodeling type and age at surgery, sex, preoperative diagnosis, body mass index, or postoperative activity level. There was also no association between initial implant alignment and remodeling type. Cortical thickening in the distal hypertrophy group was an early phenomenon occurring primarily within the first 2 years, whereas cortical thinning begins later and is a more progressive process. CONCLUSIONS: These data show remodeling after cemented Charnley total hip arthroplasty is not related to patient demographic variables; however, distal cortical hypertrophy can be predicted in the early postoperative period. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
    No preview · Article · Feb 2013 · Clinical Orthopaedics and Related Research
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    ABSTRACT: This five-year prospective study was designed to investigate periprosthetic bone remodeling associated with two cemented stem models, ABG-II (Stryker) and VerSys (Zimmer), randomly implanted in patients older than 75years. The sample consisted of 64 cases (32, ABG-II; 32, VerSys). Inclusion criterion was diagnosis of osteoarthritis recommended for cemented total hip arthroplasty. Besides clinical study, Finite Element (FE) simulation was used to analyze biomechanical changes caused by hip arthroplasty. Bone Mineral Density (BMD) measurements showed a progressive increase in bone mass throughout the entire follow-up period for both stems, well correlated with FE results except in Gruen zones 4, 5, 6 for ABG-II and in zones 4, 5 for VerSys, denoting that remodeling in those zones does not depend on mechanical factors but rather on biological or physiological ones.
    Full-text · Article · May 2013 · The Journal of arthroplasty
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