Revision Rates After Total Ankle Arthroplasty in Sample-Based Clinical Studies and National Registries

Innsbruck Medical University, Department of Orthopaedic Surgery, Innsbruck Austria.
Foot & Ankle International (Impact Factor: 1.51). 08/2011; 32(8):740-5. DOI: 10.3113/FAI.2011.0740
Source: PubMed

ABSTRACT The aim of this study was to evaluate the outcome of specific implants in total ankle arthroplasty as reported in clinical studies and determined by national registries. MATERIALS and
A structured literature review was conducted regarding sample-based clinical studies and national registry data. To allow for comparative analyses, registry data had to be available for the implants included. These were STAR Ankle, Büchel-Pappas, Hintegra, Mobility, Agility, and Ramses Total Ankle Arthroplasty. The revision rate was used as the main outcome parameter.
On average, the revision rates published in sample-based clinical studies were about half the value found in registries. Implant developers represent a share of almost 50% of the published content and are therefore over-represented in scientific publications. The inventors of STAR Ankle and BP total ankle implants published data which was statistically significantly superior to the outcome achieved in average patients as documented in registries. Irrespective of the implant, the average revision rate to be expected according to the registry data available is 21.8% after 5 years, and 43.5% after 10 years.
The average revision rate published in peer-reviewed scientific articles was significantly lower than the outcome achieved according to national arthroplasty registry data, which reflect actual average patient care in the respective countries. Publications by some research groups, particularly by implant inventors, show a deviation from the outcome published by other users and those shown in registry data.

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    • "The implant survival rate of total ankle replacement (TAR) is only 70–98% at 5–6 years, 80–95% at 8–10 years (Easley et al., 2011), and can drop to 45% at 15 years (Brunner et al., 2013). Failure causes include aseptic loosening, subsidence, cysts formation , peri-prosthetic and polyethylene fracture (Conti and Wong, 2001; Besse et al., 2009; Bonnin et al., 2011; Labek et al., 2011; Brunner et al., 2013). "
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    ABSTRACT: Total ankle replacement remains a less satisfactory solution compared to other joint replacements. The goal of this study was to develop and validate a finite element model of total ankle replacement, for future testing of hypotheses related to clinical issues. To validate the finite element model, an experimental setup was specifically developed and applied on 8 cadaveric tibias. A non-cemented press fit tibial component of a mobile bearing prosthesis was inserted into the tibias. Two extreme anterior and posterior positions of the mobile bearing insert were considered, as well as a centered one. An axial force of 2kN was applied for each insert position. Strains were measured on the bone surface using digital image correlation. Tibias were CT scanned before implantation, after implantation, and after mechanical tests and removal of the prosthesis. The finite element model replicated the experimental setup. The first CT was used to build the geometry and evaluate the mechanical properties of the tibias. The second CT was used to set the implant position. The third CT was used to assess the bone-implant interface conditions. The coefficient of determination (R-squared) between the measured and predicted strains was 0.91. Predicted bone strains were maximal around the implant keel, especially at the anterior and posterior ends. The finite element model presented here is validated for future tests using more physiological loading conditions.
    Journal of Biomechanics 12/2013; 47(3). DOI:10.1016/j.jbiomech.2013.12.022 · 2.75 Impact Factor
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    ABSTRACT: Revision of failed total ankle replacement remains a challenge with limited information available to guide treatment options. I undertook a systematic review of electronic databases and other relevant sources to identify material relating to the incidence of revision after primary implantation of the Agility™ Total Ankle Replacement System. In an effort to procure the highest quality studies available, studies were eligible for inclusion only if they involved patients undergoing primary Agility™ Total Ankle Replacement; had evaluated patients at a mean follow-up of 12 months or longer; included details of the revision performed; and included revision etiologies of aseptic loosening, ballooning osteolysis, cystic changes, malalignment, or instability. A total of 14 studies involving 2312 ankles, with a weighted mean follow-up of 22.8 months, were included. Of the 2312 ankles, 224 (9.7%) underwent revision, of which 182 (81.3%) underwent implant component replacement, 34 (15.2%) underwent arthrodesis, and 8 (3.6%) underwent below-knee amputation. No significant effect from the surgeon's learning curve on the incidence of revision or the type of revision surgery performed was identified. However, excluding the inventor increased the incidence of revision twofold, from 6.6% to 12.2%, and skewed the type of revision away from arthrodesis and toward implant component replacement or below-knee amputation. Regardless, the incidence of revision after primary implantation of the Agility™ Total Ankle Replacement System was less than historically reported and amenable to implant component revision more than 80% of the time. However, methodologically sound cohort studies are needed that include the outcomes after revision surgery, specifically focusing on what implant component replacement techniques are effective in enhancing survivorship of these revised implants and the role of custom-stemmed talar and tibial components have in revision of the Agility™ Total Ankle Replacement System. A direct comparison of the incidence of revision between the various contemporary total ankle replacement systems in common use is also warranted.
    The Journal of foot and ankle surgery: official publication of the American College of Foot and Ankle Surgeons 12/2011; 51(2):198-204. DOI:10.1053/j.jfas.2011.11.002 · 0.85 Impact Factor
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    ABSTRACT: Hip resurfacing arthroplasty has gained popularity for treating young and active patients who have arthritis. There are two major data sources for assessing outcome and revision rate after total joint arthroplasty: sample-based clinical trials and national arthroplasty registers. The purpose of this study was to evaluate the outcome of the Birmingham Hip Resurfacing (BHR) arthroplasty in terms of revision rate as reported in clinical studies and recorded by national arthroplasty registers. A comprehensive literature research was performed from English-language, peer-reviewed journals and annual reports from national joint arthroplasty registers worldwide. Only publications from MEDLINE-listed journals were included. The revision rate was used as the primary outcome parameter. In order to allow for direct comparison of different data sets, calculation was based on revisions per 100 observed component years. For statistical analysis, confidence intervals (CI) were calculated. A total of 18,708 implants, equivalent to 106,565 observed component years, were analysed in the follow-up studies. The register reports contained 9,806 primary cases corresponding to 44,294 observed component years. Statistical analysis revealed a significant difference in revisions per 100 observed component years between the development team (0.27; CI: 0.14-0.40) and register data (0.74; CI: 0.72-0.76). The BHR arthroplasty device shows good results in terms of revision rate in register data as well as in clinical studies. However, the excellent results reported by the development team are not reproducible by other surgeons. Based on the results of our study, we believe that comprehensive national arthroplasty registers are the most suitable tool for assessing hip arthroplasty revision rate.
    International Orthopaedics 02/2012; 36(7):1349-54. DOI:10.1007/s00264-012-1502-0 · 2.11 Impact Factor
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