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Background and purpose - CT (computed tomography) based methods have lately been considered an alternative to radiostereometry (RSA) for assessing early implant migration. However, no study has directly compared the 2 methods in a clinical setting. We estimated the precision and effective radiation dose of a CT-based method and compared it with marker-based RSA in 10 patients with hip arthroplasty.Patients and methods - We included 10 patients who underwent total hip replacement with a cemented cup. CT and RSA double examinations were performed postoperatively, and precision and effective dose data were compared. The CT data was analyzed with CT micromotion analysis (CTMA) software both with and without the use of bone markers. The RSA images were analyzed with RSA software with the use of bone markers.Results - The precision of CTMA with bone markers was 0.10-0.16 mm in translation and 0.31°-0.37° in rotation. Without bone markers, the precision of CTMA was 0.10-0.16 mm in translation and 0.21°-0.31° in rotation. In comparison, the precision of RSA was 0.09-0.26 mm and 0.43°-1.69°. The mean CTMA and RSA effective dose was estimated at 0.2 mSv and 0.04 mSv, respectively.Interpretation - CTMA, with and without the use of bone markers, had a comparable precision to RSA. CT radiation doses were slightly higher than RSA doses but still at a considerably low effective dose.

Physeal closure after slipped capital femoral epiphysis fixation can be difficult to assess on two-dimensional conventional radiographs. Radiostereometric analysis offers improved motion detection over conventional radiography, whereas the EOS biplanar imager provides a means for low radiation weight-bearing images. This phantom study assessed the reliability of measuring motion using radiostereometric analysis in the EOS using a slipped capital femoral epiphysis model. The accuracy and precision were better than 0.09±0.05 mm and 0.20°±0.36° when centered in the imaging space, were within the limits of clinical significance, and were not different from a standard uniplanar radiostereometric system.

Introduction: Increasing pressure in the clinic requires a more standardized approach to radiostereometric analysis (RSA) imaging. The aim of this study was to investigate whether implementation of personalized RSA patient protocols could increase image quality and decrease examination time and the number of exposure repetitions., Methods: Forty patients undergoing primary total hip arthroplasty were equally randomized to either a case or a control group. Radiographers in the case group were assisted by personalized patient protocols containing information about each patient's post-operative RSA imaging. Radiographers in the control group used a standard RSA protocol., Results: At three months, radiographers in the case group significantly reduced (p < 0.001) the number of exposures by 1.6, examination time with 19.2 min, and distance between centrum of prosthesis and centrum of calibration field with 34.1 mm when compared to post-operative (baseline) results. At twelve months, the case group significantly reduced (p < 0.001) number of exposures by two, examination time with 22.5 min, and centrum of prosthesis to centrum of calibration field distance with 43.1 mm when compared to baseline results. No significant improvements were found in the control group at any time point., Conclusion: There is strong evidence that personalized RSA patient protocols have a positive effect on image quality and radiation dose savings. Implementation of personal patient protocols as a RSA standard will contribute to the reduction of examination time, thus ensuring a cost benefit for department and patient safety., (Copyright © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.)

Purpose: Stereoradiography imaging (SRI) is an accurate and reliable low-dose radiographic method. However, patients must remain motionless during image acquisition. Motion artifacts are frequently noted. The aims of the study were to determine the incidence of the SRI motion artifact and assess if motion during SRI acquisition affects radiographic measurements., Methods: In this retrospective study, 198 patients with spinal instrumentation had biplanar SRI radiographs performed, of whom 39 had concomitant conventional radiographs. Eight coronal and sagittal spinal parameters were independently measured on SRI and conventional radiographs for the 39 patients by 2 observers. Inclusion criteria were: presence of spinal instrumentation of more than six levels and an SRI motion artifact identified on the coronal and/or the sagittal views on either the spinal rods or on the limbs. Means were compared between both types of radiographs using the Student's t test; intraclass correlation coefficients (ICCs) were used for intraobserver reproducibility and interrater reliability., Results: A motion artifact was identified in 19.7 % (n = 39, mean age 19.5 ± 1.7 years) of the cases. There were no differences in any of the coronal or sagittal plane measurements between SRI and X-rays. Intraobserver reliability and interrater reproducibility was high (range 0.81-0.98)., Conclusions: Motion artifact during full-spine stereoradiography imaging acquisition is frequent, but does not affect spinal measurements. SRI with a motion artifact can be used to produce reliable measurements of the sagittal and coronal parameters. Some SRI images with a motion artifact may suggest loss of fixation or bending of the rods. However, after becoming familiar with the appearance of the motion artifact, repeat radiographs are rarely indicated., Irb Number: 14-004872., Level of Evidence: Level IV.

Introduction: Producing x-ray images for radiostereometric analysis (RSA) is a demanding technique. Suboptimal examinations result in a high percentage of exposure repetition. The aim of this pilot study was to use an experiential training approach to sharpen the skills of radiographers in acquiring images of an optimal quality., Methods: A controlled trial using action research strategy was used. The study entailed a two phased approach. Radiographers were purposefully recruited and trained to perform the required investigations. Each phase included 12 examinations of a total knee arthroplasty phantom followed by 10 patient examinations. The quality of all x-ray images performed during the two phases was characterized by measuring the number of visible beads, the center position of the prosthesis (CP) compared to the center of calibration field (CCF). The number of re-exposures used to obtain a usable image during patient examinations was also recorded., Results: The radiographers undergoing the training resulted in a significant improvement in the quality of images produced and visualization of the beads. That is, the ability to move the CP on average 36.1 mm closer to the CCF (p < 0.001), the number of visible beads increased by 3.1 (p < 0.001) and radiographers needed 2.1-2.9 exposures less to obtain RSA images of sufficient qualities during patient examinations in phase 2 (p < 0.001)., Conclusion: This study illustrates the value of experiential method of teaching and learning with minimal compromise on patient safety but a significant contribution in terms of establishing quality of RSA images., (Copyright © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.)

Introduction: The purpose of this study was to design and evaluate a radiostereometric analysis (RSA) program aimed at radiographers in order to increase their cognitive and practical skills, thereby increasing image quality and minimizing exposure repetition., Methods and Materials: Twenty radiographers were randomized into two identically sized study groups. Training consisted of a theoretical and practical workshop using a phantom. Tests were performed to compare the effect of training to nontraining, and the effect of time duration on the maintenance of RSA skills. The effect of training was measured by a written test and three defined parameters influencing image quality., Results: Group A reduced significantly (p < 0.001) by 31.3 mm (21-31%) the distance between the centrum of the prosthesis (CP) and the centrum of the calibration field (CCF) and increased the number of beads (NB) visible by 3.6 (out of 18). A further significant reduction of 5.1 mm (p = 0.023), 1.0 bead more (p < 0.001) and a 2.1 (p = 0.022) point better rotation of the prosthesis (RP) was registered two months later. Group B was tested twice without training and no significant improvement was registered. One month after training group B had experienced overall significant improvement on a par with group A., Conclusion: It is realistic to implement an RSA X-ray training program where radiographers significantly improve their theoretical and practical skills in centering the CP closer to the CCF, NB and RP. A duration of up to two months after training does not influence the quality of participants' performance., (Copyright © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.)

Background and purpose - Radiostereometric analysis (RSA) is an accurate method for measurement of early migration of implants. Since a relation has been shown between early migration and future loosening of total knee and hip prostheses, RSA plays an important role in the development and evaluation of prostheses. However, there have been few RSA studies of the upper limb, and the value of RSA of the upper limb is not yet clear. We therefore performed a systematic review to investigate the accuracy and precision of RSA of the upper limb. Patients and methods - PRISMA guidelines were followed and the protocol for this review was published online at PROSPERO under registration number CRD42016042014. A systematic search of the literature was performed in the databases Embase, Medline, Cochrane, Web of Science, Scopus, Cinahl, and Google Scholar on April 25, 2015 based on the keywords radiostereometric analysis, shoulder prosthesis, elbow prosthesis, wrist prosthesis, trapeziometacarpal joint prosthesis, humerus, ulna, radius, carpus. Articles concerning RSA for the analysis of early migration of prostheses of the upper limb were included. Quality assessment was performed using the MINORS score, Downs and Black checklist, and the ISO RSA Results - 23 studies were included. Precision values were in the 0.06-0.88 mm and 0.05-10.7° range for the shoulder, the 0.05-0.34 mm and 0.16-0.76° range for the elbow, and the 0.16-1.83 mm and 11-124° range for the TMC joint. Accuracy data from marker- and model-based RSA were not reported in the studies included. Interpretation - RSA is a highly precise method for measurement of early migration of orthopedic implants in the upper limb. However, the precision of rotation measurement is poor in some components. Challenges with RSA in the upper limb include the symmetrical shape of prostheses and the limited size of surrounding bone, leading to over-projection of the markers by the prosthesis. We recommend higher adherence to RSA guidelines and encourage investigators to publish long-term follow-up RSA studies.

Radiostereometric analysis (RSA) is the gold standard evaluating micromovements after total hip arthroplasty. The aim of this study was to investigate the migratory pattern of an uncemented femoral stem during the first 2 years after surgery. We followed 28 patients with a mean age of 57 (SD 13) years for the first two postoperative years. Radiostereometric analysis was used to measure the translation and rotation of the femoral component. The Harris hip score (HHS) was determined to evaluate the clinical outcome. No stem had to be revised. The mean HHS advanced from 35 (SD 11) preoperative to 89 (SD 10) 1 year after surgery. At the end of the observation period, mean subsidence of the stem was 0.26 mm (SD 0.82). Maximum total point motion (MTPM) was 1.23 mm (SD 1.22). The main distal migration took place up to 6 weeks after surgery with nearly no further subsidence up to 2 years postoperatively. All the measured migrations of the hip stem were very small. Results of the HHS demonstrate good clinical outcome. Long-term RSA is necessary to assess possible late migration of the Cerafit standard femoral stem.

Background and Purpose: Guidelines for standardization of radiostereometry (RSA) of implants were published in 2005 to facilitate comparison of outcomes between various research groups. In this systematic review, we determined how well studies have adhered to these guidelines., Methods: We carried out a literature search to identify all articles published between January 2000 and December 2011 that used RSA in the evaluation of hip or knee prosthesis migration. 2 investigators independently evaluated each of the studies for adherence to the 13 individual guideline items. Since some of the 13 points included more than 1 criterion, studies were assessed on whether each point was fully met, partially met, or not met., Results: 153 studies that met our inclusion criteria were identified. 61 of these were published before the guidelines were introduced (2000-2005) and 92 after the guidelines were introduced (2006-2011). The methodological quality of RSA studies clearly improved from 2000 to 2011. None of the studies fully met all 13 guidelines. Nearly half (43) of the studies published after the guidelines demonstrated a high methodological quality and adhered at least partially to 10 of the 13 guidelines, whereas less than one-fifth (11) of the studies published before the guidelines had the same methodological quality. Commonly unaddressed guideline items were related to imaging methodology, determination of precision from double examinations, and also mean error of rigid-body fitting and condition number cutoff levels., Interpretation: The guidelines have improved methodological reporting in RSA studies, but adherence to these guidelines is still relatively low. There is a need to update and clarify the guidelines for clinical hip and knee arthroplasty RSA studies.

Radiostereometry (RSA) is considered to be the most precise and accurate method for wear-measurements in total hip replacement. Post-operative stereoradiographs has so far been necessary for wear measurement. Hence, the use of RSA has been limited to studies planned for RSA measurements. We compared a new RSA method for wear measurements that does not require previous radiographs with conventional RSA. Instead of comparing present stereoradiographs with post-operative ones, we developed a method for calculating the post-operative position of the center of the femoral head on the present examination and using this as the index measurement. We compared this alternative method to conventional RSA in 27 hips in an ongoing RSA study. We found a high degree of agreement between the methods for both mean proximal (1.19 mm vs. 1.14 mm) and mean 3D wear (1.52 mm vs. 1.44 mm) after 10 years. Intraclass correlation coefficients (ICC) were 0.958 and 0.955, respectively (p<0.001 for both ICCs). The results were also within the limits of agreement when plotted subject-by-subject in a Bland-Altman plot. Our alternative method for wear measurements with RSA offers comparable results to conventional RSA measurements. It allows precise wear measurements without previous radiological examinations., (Copyright © 2012 Orthopaedic Research Society.)

Background: Different techniques have been used to quantify the movement of sacroiliac (SI) joints. These include radiostereometric analysis (RSA), but the accuracy and precision of this method have not been properly evaluated and it is unclear how many markers are required and where they should be placed to achieve proper accuracy and precision., Purpose: The purpose of this study was to test accuracy and precision of RSA, applied to the SI joint, in a phantom model and in patients., Methods: We used a plastic phantom attached to a micrometer to obtain a true value of the movement of the SI joint and compared this value with the measured value obtained by RSA; the difference represented the accuracy. The precision of the system was measured by double examination in the phantom and in six patients, and was expressed by a limit of significance (LOS). We analyzed different marker distributions to find optimal marker placement and number of markers needed., Results: The accuracy was high and we identified no systematic errors. The precision of the phantom was high with a LOS less than 0.25° and 0.16 mm for all directions, and in patients, the precision was less than 0.71° for rotations and 0.47 mm translations. No markers were needed in the pubic symphysis to obtain good precision., Conclusions: The accuracy and precision are high when RSA is used to measure movement in the SI joint and support the use of RSA in research of SI joint motion.

Introduction: Although the overall survival of knee and hip prostheses at ten years averages 90%, recent problems with several hip and knee prostheses have illustrated that the orthopaedic community, industry, and regulators can still further improve patient safety. Given the early predictive properties of roentgen stereophotogrammetric analysis (RSA) and the meticulous follow-up of national joint registries, these two methods are ideal tools for such a phased clinical introduction. In this paper, we elaborate on the predictive power of RSA within a two-year follow-up after arthroplasty and its relationship to national joint registries. The association between RSA prosthesis-migration data and registry data is evaluated., Methods: The five-year rate of revision of RSA-tested total knee replacements was compared with that of non-RSA-tested total knee replacements. Data were extracted from the published results of the national joint registries of Sweden, Australia, and New Zealand., Results: There was a 22% to 35% reduction in the number of revisions of RSA-tested total knee replacements as compared with non-RSA-tested total knee replacements in the national joint registries. Assuming that the total cost of total knee arthroplasty is $37,000 in the United States, a 22% to 35% reduction in the number of revisions (currently close to 55,000 annually) could lead to an estimated annual savings of over $400 million to the health-care system., Conclusion: The phased clinical introduction of new prostheses with two-year RSA results as a qualitative tool could lead to better patient care and could reduce the costs associated with revision total knee arthroplasty. Follow-up in registries is necessary to substantiate these results and to improve post-market surveillance.