Aims

The modified Radiological Union Scale for Tibia (mRUST) fractures score was developed in order to assess progress to union and define a numerical assessment of fracture healing of metadiaphyseal fractures. This score has been shown to be valuable in predicting radiological union; however, there is no information on the sensitivity, specificity, and accuracy of this index for various cut-off scores. The aim of this study is to evaluate sensitivity, specificity, accuracy, and cut-off points of the mRUST score for the diagnosis of metadiaphyseal fractures healing.

Aims

The primary aim of this study was to report the radiological outcomes of patients with a dorsally displaced distal radius fracture who were randomized to a moulded cast or surgical fixation with wires following manipulation and closed reduction of their fracture. The secondary aim was to correlate radiological outcomes with patient-reported outcome measures (PROMs) in the year following injury.

Aims

Limb-lengthening nails have largely replaced external fixation in limb-lengthening and reconstructive surgery. However, the adverse events and high prevalence of radiological changes recently noted with the STRYDE lengthening nail have raised concerns about the use of internal lengthening nails. The aim of this study was to compare the prevalence of radiological bone abnormalities between STRYDE, PRECICE, and FITBONE nails prior to nail removal.

Aims. Although CT is considered the benchmark to measure femoral version, 3D biplanar radiography (hipEOS) has recently emerged as a possible alternative with reduced exposure to ionizing radiation and shorter examination time. The aim of our study was to evaluate femoral stem version in postoperative total hip arthroplasty (THA) patients and compare the accuracy of hipEOS to CT. We hypothesize that there will be no significant difference in calculated femoral stem version measurements between the two imaging methods. Methods. In this study, 45 patients who underwent THA between February 2016 and February 2020 and had both a postoperative CT and EOS scan were included for evaluation. A fellowship-trained musculoskeletal radiologist and radiological technician measured femoral version for CT and 3D EOS, respectively. Comparison of values for each imaging modality were assessed for statistical significance. Results. Comparison of the mean postoperative femoral stem version measurements between CT and 3D hipEOS showed no significant difference (p = 0.862). In addition, the two version measurements were strongly correlated (r = 0.95; p < 0.001), and the mean paired difference in postoperative femoral version for CT scan and 3D biplanar radiography was -0.09° (95% confidence interval -1.09 to 0.91). Only three stem measurements (6.7%) were considered outliers with a > 5° difference. Conclusion. Our study supports the use of low-dose biplanar radiography for the postoperative assessment of femoral stem version after THA, demonstrating high correlation with CT. We found no significant difference for postoperative femoral version when comparing CT to 3D EOS. We believe 3D EOS is a reliable option to measure postoperative femoral version given its advantages of lower radiation dosage and shorter examination time. Cite this article: Bone Joint J 2022;104-B(11):1196–1201

Abstract. Background. Post operative radiographs following total joint arthroplasty are requested as part of routine follow up in many institutions. These studies have a significant cost to the local departments, in terms of financial and clinic resources, however, previous research has suggested they may not alter the course of the patients treatment. The purpose of this study was to assess the significance of elective post operative radiographs on changes in management of patients who underwent total joint arthroplasty. Method. All patients who underwent total knee arthroplasty and total hip arthroplasty at a District General Hospital from 2019 to 2020 were included. Data was collected retrospectively from medical records and radiograph requests. Alterations to clinical management based on radiographic findings were reviewed in clinic letters. Results. A total of 227 Total joint arthroplasty were retrieved. With 111(49%) total hip arthroplasty and 116 (51%) total knee arthroplasty. 54 were excluded due to having no clinical follow up and 173 met inclusion criteria. 56 (32%) had their post operative elective radiograph, while 93 (53.8%) patients had none. There were no abnormalities detected from the elective radiographs and none of the patients returned to the theatre. 24 patients (13%) presented with symptoms and had non-elective radiographs, 16 (67%) did not have any interventions and 8 (4.6%) required intervention and were taken to theatre. Discussion: Not performing these radiographs saves time, cost, and prevents unnecessary radiation exposure. In our institution, a 2-view joint radiograph costs £29 and takes roughly 15 minutes. This does not include indirect costs of additional clinic time and patient waiting time. In the larger context, the cost associated with elective radiographs is significant and our data suggests that routine post-operative radiographs are not beneficial as part of standard post-operative protocol for asymptomatic patients. However, performing imaging remains beneficial for patients who re-present with symptoms. Conclusion. Routine elective post-operative joint radiographs did not detect any true abnormalities. Information from elective radiographs has no clinical significance and did not change management. Therefore, this study recommends that there is no rationale requesting elective post-operative joint radiographs. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Malalignment is often postulated as the main reason for the high failure rate of total ankle replacements (TARs). Only a few studies have been performed to correlate radiographic TAR malalignment to the clinical outcome, but no consistent trends between TAR alignment parameters and the clinical outcome were found. No standard TAR alignment measurement method is present, so reliable comparison between studies is difficult. Standardizing TAR alignment measurements and increasing measurable parameters on radiographs in the clinic might lead to a better insight into the correlation between malalignment and the clinical outcome. This study aims to develop and validate a tool to semi-automatic measure TAR alignment, and to improve alignment measurement on radiographs in the clinic. A tool to semi-automatically measure TAR alignment on anteroposterior and lateral radiographs was developed and used by two observers to measure TAR alignment parameters of ten patients. The Intraclass Coefficient (ICC) was calculated and accuracy was compared to the manual measurement method commonly used in the clinic. The tool showed an accuracy of 76% compared to 71% for the method used during follow-up in the clinic. ICC values were 0.94 (p<0.01) and higher for both inter-and intra-observer reliability. The tool presents an accurate, consistent, and reliable method to measure TAR alignment parameters. Three-dimensional alignment parameters are obtained from two-dimensional radiographs, and as the tool can be applied to any TAR design, it offers a valuable addition in the clinic and for research purposes

Introduction. Routine radiographs in the follow-up of circular frames is commonplace, however the effect on clinical decision making is unclear. Previous work locally has suggested that >95% of radiographs, particularly at early time points, do not affect clinical management. This study was conducted to assess the impact of a transition to early remote follow-up on circular frame patients with limited radiographic assessment. Materials and Methods. Patients were identified from a prospective limb reconstruction database. Data were collected including the number of clinic appointments, type of clinic appointment, number of radiographs performed, and impact this had on clinical management. This was compared to our previous cohort of 85 patients undergoing standard follow-up. Results. Fourteen patients were eligible for inclusion (mean age 45, range 26–75). Circular frames were indicated for trauma (12), or limb reconstruction (2). Following introduction of remote follow-up, the mean number of face-to-face appointments reduced from 6.1 to 1.7 to the point of frame removal. Conversion from telephone follow-up to face-to-face follow-up was required in just one case where hardware failure occurred. The number of radiographs during treatment was reduced from a mean of 22 to 11 (range 4–20). Conclusions. Remote follow-up of circular frame patients was associated with significantly fewer radiographs and face-to-face appointments, without significantly increasing complications. We believe this is a safe and effective method of follow-up, optimising resource use in line with the NHS long term plan. Data collection is ongoing, and a larger cohort would be available for presentation

Knee joint distraction (KJD) has been associated with clinical and structural improvement and synovial fluid (SF) marker changes. However, structural changes have not yet been shown satisfactorily in regular care, since radiographic acquisition was not fully standardized. AI-based modules have shown great potential to reduce reading time, increase inter-reader agreement and therefore function as a tool for treatment outcome assessment. The objective was to analyse structural changes after KJD in patients using this AI-based measurement method, and relate these changes to clinical outcome and SF markers. 20 knee OA patients (<65 years old) were included in this study. KJD treatment was performed using an external fixation device, providing 5 mm distraction for 6 weeks. SF was aspirated before, during and immediately after treatment. Weight-bearing antero-posterior knee radiographs and WOMAC questionnaires were collected before and ~one year after treatment. Radiographs were analysed with the Knee Osteoarthritis Labelling Assistant (KOALA, IB Lab GmbH, Vienna, Austria), and 10 pre-defined biomarker levels in SF were measured by immunoassay. Radiographic one-year changes were analysed and linear regression was used to calculate associations between changes in standardized joint space width (JSW) and WOMAC, and changes in JSW and SF markers. After treatment, radiographs showed an improvement in Kellgren-Lawrence grade in 7 of 16 patients that could be evaluated; 3 showed a worsening. Joint space narrowing scores and continuous JSW measures improved especially medially. A greater improvement in JSW was significantly associated with a greater improvement in WOMAC pain (β=0.64;p=0.020). A greater increase in MCP1 (β=0.67;p=0.033) and lower increase in TGFβ1 (β=-0.787;p=0.007) were associated with JSW improvement. Despite the small number of patients, also in regular care KJD treatment shows joint repair as measured automatically on radiographs, significantly associated with certain SF marker change and even with clinical outcome

Introduction and Objective. Up to 30% of thoracolumbar (TL) fractures are missed in the emergency room. Failure to identify these fractures can result in neurological injuries up to 51% of the casesthis article aimed to clarify the incidence and risk factors of traumatic fractures in China. The China National Fracture Study (CNFS. Obtaining sagittal and anteroposterior radiographs of the TL spine are the first diagnostic step when suspecting a traumatic injury. In most cases, CT and/or MRI are needed to confirm the diagnosis. These are time and resource consuming. Thus, reliably detecting vertebral fractures in simple radiographic projections would have a significant impact. We aim to develop and validate a deep learning tool capable of detecting TL fractures on lateral radiographs of the spine. The clinical implementation of this tool is anticipated to reduce the rate of missed vertebral fractures in emergency rooms. Materials and Methods. We collected sagittal radiographs, CT and MRI scans of the TL spine of 362 patients exhibiting traumatic vertebral fractures. Cases were excluded when CT and/or MRI where not available. The reference standard was set by an expert group of three spine surgeons who conjointly annotated (fracture/no-fracture and AO Classification) the sagittal radiographs of 171 cases. CT and/or MRI were used confirm the presence and type of the fracture in all cases. 302 cropped vertebral images were labelled “fracture” and 328 “no fracture”. After augmentation, this dataset was then used to train, validate, and test deep learning classifiers based on the ResNet18 and VGG16 architectures. To ensure that the model's prediction was based on the correct identification of the fracture zone, an Activation Map analysis was conducted. Results. Vertebras T12 to L2 were the most frequently involved, accounting for 48% of the fractures. Accuracies of 88% and 84% were obtained with ResNet18 and VGG16 respectively. The sensitivity was 89% with both architectures but ResNet18 had a significantly higher specificity (88%) compared to VGG16 (79%). The fracture zone used was precisely identified in 81% of the heatmaps. Conclusions. Our AI model can accurately identify anomalies suggestive of TL vertebral fractures in sagittal radiographs precisely identifying the fracture zone within the vertebral body

Polyethylene wear represents a significant risk factor for the long-term success of knee arthroplasty [1]. This work aimed to develop and in vivo validate an automated algorithm for accurate and precise AI based wear measurement in knee arthroplasty using clinical AP radiographs for scientifically meaningful multi-centre studies. Twenty postoperative radiographs (knee joint AP in standing position) after knee arthroplasty were analysed using the novel algorithm. A convolutional neural network-based segmentation is used to localize the implant components on the X-Ray, and a 2D-3D registration of the CAD implant models precisely calculates the three-dimensional position and orientation of the implants in the joint at the time of acquisition. From this, the minimal distance between the involved implant components is determined, and its postoperative change over time enables the determination of wear in the radiographs. The measured minimum inlay height of 335 unloaded inlays excluding the weight-induced deformation, served as ground truth for validation and was compared to the algorithmically calculated component distances from 20 radiographs. With an average weight of 94 kg in the studied TKA patient cohort, it was determined that an average inlay height of 6.160 mm is expected in the patient. Based on the radiographs, the algorithm calculated a minimum component distance of 6.158 mm (SD = 81 µm), which deviated by 2 µm in comparison to the expected inlay height. An automated method was presented that allows accurate and precise determination of the inlay height and subsequently the wear in knee arthroplasty based on a clinical radiograph and the CAD models. Precision and accuracy are comparable to the current gold standard RSA [2], but without relying on special radiographic setups. The developed method can therefore be used to objectively investigate novel implant materials with meaningful clinical cohorts, thus improving the quality of patient care

Objectives. The radiographic union score for tibial (RUST) fractures was developed by Whelan et al to assess the healing of tibial fractures following intramedullary nailing. In the current study, the repeatability and reliability of the RUST score was evaluated in an independent centre (a) using the original description, (b) after further interpretation of the description of the score, and (c) with the immediate post-operative radiograph available for comparison. Methods. A total of 15 radiographs of tibial shaft fractures treated by intramedullary nailing (IM) were scored by three observers using the RUST system. Following discussion on how the criteria of the RUST system should be implemented, 45 sets (i.e. AP and lateral) of radiographs of IM nailed tibial fractures were scored by five observers. Finally, these 45 sets of radiographs were rescored with the baseline post-operative radiograph available for comparison. Results. The initial intraclass correlation (ICC) on the first 15 sets of radiographs was 0.67 (95% CI 0.63 to 0.71). However, the original description was being interpreted in different ways. After agreeing on the interpretation, the ICC on the second cohort improved to 0.75. The ICC improved even further to 0.79, when the baseline post-operative radiographs were available for comparison. Conclusion. This study demonstrates that the RUST scoring system is a reliable and repeatable outcome measure for assessing tibial fracture healing. Further improvement in the reliability of the scoring system can be obtained if the radiographs are compared with the baseline post-operative radiographs. Cite this article: Mr J.M. Leow. The radiographic union scale in tibial (RUST) fractures: Reliability of the outcome measure at an independent centre. Bone Joint Res 2016;5:116–121. DOI: 10.1302/2046-3758.54.2000628

Introduction. Cross table lateral (CTL) radiographs are commonly used to measure acetabular component anteversion after total hip arthroplasty (THA). CTL measurements may differ by >10 degrees from CT scan measurements, but the reasons for this discrepancy are poorly understood. We compare anteversion measurements made on CTL radiographs and CT scans to identify spinopelvic parameters predictive of inaccuracy. Methods. THA patients (n=47) with preoperative spinopelvic radiographic analysis and postoperative CT scans were retrospectively reviewed. Acetabular component anteversion was measured on post-operative CTL radiographs, and CT scans using 3D reconstructions of the pelvis. Patients were grouped by error (CTL-CT)>10° (n=11) or <10° (n=36), and spinopelvic mobility parameters were compared using t-tests. Correlation between error and mobility parameters was assessed with Pearson coefficient. Results. Patients with CTL error >10° (range 10–14) had stiffer lumbar spines with less lumbar flexion (38° vs 47°, p=0.03), greater sagittal imbalance measured by pelvic incidence-lumbar lordosis mismatch (6° vs −2°, p=0.04), more pelvic extension when seated (pelvic tilt −10° vs −2°, p=0.05), and greater change in pelvic tilt between supine and seated positions (13° vs 4°, p=0.04). The error of CTL measurements showed a positive correlation with increased CTL anteversion (r=0.5, p=0.001), standing lordosis (r=0.23, p=0.05), seated lordosis (r=0.4, p=0.01) and pelvic tilt change between supine and step-up positions (r=0.34, p=0.01). Discussion. Differences in spinopelvic mobility patterns may explain the variable accuracy of acetabular anteversion measurements on CTL radiographs. Patients with stiff spines and increased compensatory pelvic motion have less accurate measurements on CTL radiographs. Flexion of the contralateral hip is required to obtain clear CTL radiographs. In patients with a stiff lumbar spine, this movement may extend the pelvis and increase anteversion of the acetabulum on CTL views. Reliable analysis of acetabular component anteversion in this patient population may require advanced imaging with a CT scan

Over the last few years low dose digital radiography (DR) has all but replaced traditional chemical image processing. This appears to have created a paradigm shift in the suitability of intraoperative radiographic guidance for total hip arthroplasty. It is the purpose of this publication to describe our preferred technique and assess its reliability in achieving the desired parameters of a successful total hip arthroplasty. A consecutive prospective evaluation of 150 primary total hip arthroplasties employing intraoperative digital radiography was carried out. An anteroposterior pelvic radiograph with the patient in the lateral decubitus position was obtained for all hips. The orientation of the intraoperative film was matched to that of the preoperative pelvic radiograph. The image was taken after placement of the acetabular component and best estimate of femoral trial size, position, and head and neck length. The DR system produced an image within 6 seconds of exposure. This trial radiograph was then used to make adjustments. Given that the cassette does not have to be moved for image processing, a precise anteroposterior film was obtained by simply adjusting the operating table. Two to three minutes were allotted for each radiograph. Corrections to stem size, cup position, screw length and position, limb length, and offset were made based on this intraoperative radiograph. The final intraoperative image was then compared to a postoperative standard radiograph in supine position at 2 weeks after total hip arthroplasty to verify the accuracy of intraoperative digital radiography. Abduction angle, limb length, offset, and canal fit and fill were assessed for confirmation of the validity of the intraoperative imaging technique. Acetabular abduction angle was determined with a mean of 43 degrees (range, 35 to 48 degrees). The intraoperative measurement was within 3 degrees of the postoperative measurement in all cases. Adjustment of acetabular cup orientation was performed 10% of the time based on the intraoperative radiograph. Apposition was within 2 mm 100% of the time. Re-seating of the cup was carried out in one hip only. Femoral component was neutral in 92% and between 3 and 5 degrees of varus in 8%. Femoral component was upsized 55% of the time. Intraoperatively measured limb length discrepancy and offset were within 3 mm of the postoperative measurement in all hips. Intraoperative digital imaging is a reliable tool for achieving the desired radiographic results in THA. The technique is efficient and affordable. The high rate of success in this series suggests that this technology should contribute to a paradigm shift in the standard of care in total hip arthroplasty

Evaluation of patient specific spinopelvic mobility requires the detection of bony landmarks in lateral functional radiographs. Current manual landmarking methods are inefficient, and subjective. This study proposes a deep learning model to automate landmark detection and derivation of spinopelvic measurements (SPM).

A deep learning model was developed using an international multicenter imaging database of 26,109 landmarked preoperative, and postoperative, lateral functional radiographs (HREC: Bellberry: 2020-08-764-A-2). Three functional positions were analysed: 1) standing, 2) contralateral step-up and 3) flexed seated. Landmarks were manually captured and independently verified by qualified engineers during pre-operative planning with additional assistance of 3D computed tomography derived landmarks. Pelvic tilt (PT), sacral slope (SS), and lumbar lordotic angle (LLA) were derived from the predicted landmark coordinates. Interobserver variability was explored in a pilot study, consisting of 9 qualified engineers, annotating three functional images, while blinded to additional 3D information. The dataset was subdivided into 70:20:10 for training, validation, and testing.

The model produced a mean absolute error (MAE), for PT, SS, and LLA of 1.7°±3.1°, 3.4°±3.8°, 4.9°±4.5°, respectively. PT MAE values were dependent on functional position: standing 1.2°±1.3°, step 1.7°±4.0°, and seated 2.4°±3.3°, p< 0.001. The mean model prediction time was 0.7 seconds per image. The interobserver 95% confidence interval (CI) for engineer measured PT, SS and LLA (1.9°, 1.9°, 3.1°, respectively) was comparable to the MAE values generated by the model.

The model MAE reported comparable performance to the gold standard when blinded to additional 3D information. LLA prediction produced the lowest SPM accuracy potentially due to error propagation from the SS and L1 landmarks. Reduced PT accuracy in step and seated functional positions may be attributed to an increased occlusion of the pubic-symphysis landmark. Our model shows excellent performance when compared against the current gold standard manual annotation process.

The function of the knee joint is to allow for locomotion and is comprised of various bodily structures including the four major ligaments; medial collateral ligament (MCL), lateral collateral ligament (LCL), anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). The primary function of the ligaments are to provide stability to the joint. The knee is prone to injury as a result of osteoarthritis as well as ligamentous and meniscal lesions. Furthermore, compromised joint integrity due to ligamentous injury may be a result of direct and indirect trauma, illness, occupational hazard as well as lifestyle. A device capable of non-invasively determining the condition of the ligaments in the knee joint would be a useful tool to assist the clinician in making a more informed diagnosis and prognosis of the injury. Furthermore, the device would potentially reduce the probability of a misdiagnosis, timely diagnosis and avoidable surgeries. The existing Laxmeter prototype (UK IPN: GB2520046) is a Stress Radiography Device currently limited to measuring the laxity of the MCL and LCL at multiple fixed degrees of knee flexion. Laxity refers to the measure of a ligament's elasticity and stiffness i.e. the condition of the ligament, by applying a known load (200N) to various aspects of the proximal tibial and thereby inducing tibial translation. The extent of translation would indicate the condition of the ligament. The Laxmeter does not feature a load applying component as of yet, however, it allows for the patient to be in the most comfortable and ideal position during radiographic laxity measurement testing. The entire structure is radiolucent and attempts to address the limitations of existing laxity measurement devices, which includes: excessive radiation exposure to the radiographic assistant, little consideration for patient ergonomics and restrictions to cruciate or collateral ligament laxity measurements. The study focusses on further developing and modifying the Laxmeter to allow for: the laxity measurement of all four major ligaments of the knee joint, foldability for improved storage and increased structural integrity. Additionally, a load applicator has been designed as an add-on to the system thereby making the Laxmeter a complete Stress Radiography Device. Various materials including Nylon, Polycarbonate, Ultra High Molecular Weight Polyethylene (UHMWPE) – PE 1000, and Acetal/ POM were tested, using the Low Dose X-ray (Lodox) scanner, to determine their radiolucency. All materials were found to be radiolucent enough for the manufacture of the Laxmeter structure as well as the load applicator in order to identify and measure the translation of the tibia with respect to the stationary femur. The Laxmeter allows for the measurement of the laxity of the MCL and LCL at multiple fixed degrees of flexion by providing the ideal patient position for testing. The next iteration of the device will present an affordable and complete Stress Radiography Device capable of measuring the laxity of all four major ligaments of the knee joint at multiple fixed degrees of flexion. Future work would include aesthetic considerations as well as an investigation into carbon-fibre-reinforced plastics

When performing scarf osteotomies some surgeons use intraoperative radiography and others do not. Our experience is that when using intraoperative radiography we often change the osteotomy position to improve the correction of the hallux valgus angle and sesamoid position. We report the results of a single surgeon series of 62 consecutive patients who underwent a scarf osteotomy for hallux valgus. The first 31 patients underwent surgery without the use of intraoperative radiographs and the subsequent 31 patients underwent surgery with the use of intraoperative radiographs, this reflects a change in the surgeons practice. Hallux valgus angle, intermetatarsal angle, distal metatarsal articular angle and sesamoid position using the Hardy Clapham grading system were recorded. All patients had measurements recorded from weight baring radiographs taken pre operatively as well as at 6 and 12 weeks post operatively. Intraoperative measurements were also recorded for all patients in the intraoperative radiography group. The mean hallux valgus angle preoperatively was 28.5° in the control group and 30.5° in the intraoperative radiography group. The mean hallux valgus angle in the control group at 6 weeks was 12.4° and at 12 weeks was 12.6°. The mean hallux valgus angle in the intraoperative radiography group at 6 weeks was 10.5° and at 12 weeks was 9.8°. The median sesamoid position pre operatively was 4 for both groups. At 6 and 12 weeks the sesamoid position improved by a median of 1 position in the control group and 2 positions in the intraoperative radiography group (p<0.05). We recommend that surgeons who do not routinely use intraoperative radiography undertake a trial of this. We have found that the use of intraoperative radiography improves the correction of hallux valgus angle and sesamoid position. These have been shown to increase patient satisfaction and reduce recurrence

Aims. The aim of this study was to analyze how proximal radial neck resorption (PRNR) starts and progresses radiologically in two types of press-fit radial head arthroplasties (RHAs), and to investigate its clinical relevance. Methods. A total of 97 patients with RHA were analyzed: 56 received a bipolar RHA (Group 1) while 41 received an anatomical implant (Group 2). Radiographs were performed postoperatively and after three, six, nine, and 12 weeks, six, nine, 12, 18, and 24 months, and annually thereafter. PRNR was measured in all radiographs in the four radial neck quadrants. The Mayo Elbow Performance Score (MEPS), the abbreviated version of the Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH), and the patient-assessed American Shoulder and Elbow Surgeons score - Elbow (pASES-E) were used for the clinical assessment. Radiological signs of implant loosening were investigated. Results. The mean follow-up was six years (2 to 14). PRNR started after a mean of 7.5 weeks (SD 2.1) and progressed significantly during the first two years, by the end of which the bone resorption stabilized. PRNR was detected in 81% (n = 45) of patients in Group 1 and 88% (n = 36) in Group 2. The final mean PRNR was 3.0 mm (SD 2.3) in Group 1 and 3.7 mm (SD 2.5) in Group 2. The mean MEPS, QuickDASH, and pASES-E were 95.9 (SD 11.5), 4.4 (SD 9.2), and 94.8 (SD 10.9) in Group 1 and 92.2 (SD 16.2), 9.9 (SD 21.5), and 90.8 (SD 15) in Group 2, respectively. No significant differences were observed between groups in the clinical and radiological outcomes. No correlations were found between PRNR and the clinical results. Conclusion. PRNR after press-fit RHA is a common radiological finding that develops in the first 24 months before stabilizing definitively. PRNR does not affect the clinical results or implant survival in the mid term. Cite this article: Bone Joint J 2023;105-B(8):905–911

Aims. To investigate if preoperative CT improves detection of unstable trochanteric hip fractures. Methods. A single-centre prospective study was conducted. Patients aged 65 years or older with trochanteric hip fractures admitted to Stavanger University Hospital (Stavanger, Norway) were consecutively included from September 2020 to January 2022. Radiographs and CT images of the fractures were obtained, and surgeons made individual assessments of the fractures based on these. The assessment was conducted according to a systematic protocol including three classification systems (AO/Orthopaedic Trauma Association (OTA), Evans Jensen (EVJ), and Nakano) and questions addressing specific fracture patterns. An expert group provided a gold-standard assessment based on the CT images. Sensitivities and specificities of surgeons’ assessments were estimated and compared in regression models with correlations for the same patients. Intra- and inter-rater reliability were presented as Cohen’s kappa and Gwet’s agreement coefficient (AC1). Results. We included 120 fractures in 119 patients. Compared to radiographs, CT increased the sensitivity of detecting unstable trochanteric fractures from 63% to 70% (p = 0.028) and from 70% to 76% (p = 0.004) using AO/OTA and EVJ, respectively. Compared to radiographs alone, CT increased the sensitivity of detecting a large posterolateral trochanter major fragment or a comminuted trochanter major fragment from 63% to 76% (p = 0.002) and from 38% to 55% (p < 0.001), respectively. CT improved intra-rater reliability for stability assessment using EVJ (AC1 0.68 to 0.78; p = 0.049) and for detecting a large posterolateral trochanter major fragment (AC1 0.42 to 0.57; p = 0.031). Conclusion. A preoperative CT of trochanteric fractures increased detection of unstable fractures using the AO/OTA and EVJ classification systems. Compared to radiographs, CT improved intra-rater reliability when assessing fracture stability and detecting large posterolateral trochanter major fragments. Cite this article: Bone Jt Open 2024;5(6):524–531

Anteroposterior (AP) radiographs remain the standard of care for pre- and post-operative imaging during total hip arthroplasty (THA), despite known limitation of plain films, including the inability to adequately account for distortion caused by variations in pelvic orientation. Of specific interest to THA surgeons are distortions associated with pelvic tilt, as unaccounted for tilt can significantly alter radiographic measurements of cup position. Several authors have proposed methods for correcting for pelvic tilt on radiographs but none have proven reliable in a THA population. The purpose of our study was to develop a method for correcting pelvic tilt on AP radiographs in patients undergoing primary or revision THA. CT scans from 20 patients/cadaver specimens (10 male, 10 female) were used to create 3D renderings, from which synthetic radiographs of each pelvis were generated (Figure 1). For each pelvis, 13 synthetic radiographs were generated, showing the pelvis at between −30° and 30° of pelvic tilt, in 5° increments. On each image, 8 unique parameters/distances were measured to determine the most appropriate parameters for calculation of pelvic tilt (Figure 2). The most reliable and accurate of these parameters was determined via regression analysis and used to create gender-specific nomograms from which pelvic tilt measurements could be calculated (Figure 3). The accuracy and reliability of the nomograms and correction method were subsequently validated using both synthetic radiographs (n=50) and stereoradiographic images (n=58). Of 8 parameters measured, the vertical distance between the superior margin of the pubic symphysis and the transischial line (PSTI) was determined to be the most reliable (r=−0.96, ICC=0.94). Mean tilt calculated from synthetic radiographs (0.6°±18.6°) correlated very strongly (r=0.96) with mean known tilt (0.5°±17.9°, p=0.98). Mean pelvic tilt calculated from AP EOS images (3.2°±9.9°) correlated strongly (r=0.77) with mean tilt measured from lateral EOS images (3.8°±8.2°, p=0.74). No gender differences were noted in mean tilt measurements in synthetic images (p=0.98) or EOS images (p=0.45). Our method of measuring PSTI and POD on AP images and applying these measurements to nomograms provides a validated and reliable method for estimating the degree of pelvic tilt on AP radiographs during THA. For any figures or tables, please contact authors directly

Introduction

There are nearly 500,000 people with undiagnosed diabetes mellitus in the UK. The incidental finding vascular calcification on plain radiographs in patients with undiagnosed diabetes has the potential to alter patient management in those presenting with pathology. We hypothesised that the presence of vascular calcification on plain radiographs of the foot may predict the diagnosis of diabetes. The primary aim of this case control study was to determine the positive predictive value of vascular calcification to diagnose diabetes. Secondary aims were to determine the odds of having diabetes dependent on other known risk factors for calcification.

Aims. Periprosthetic fractures (PPFs) following hip arthroplasty are complex injuries. This study evaluates patient demographic characteristics, management, outcomes, and risk factors associated with PPF subtypes over a decade. Methods. Using a multicentre collaborative study design, independent of registry data, we identified adults from 29 centres with PPFs around the hip between January 2010 and December 2019. Radiographs were assessed for the Unified Classification System (UCS) grade. Patient and injury characteristics, management, and outcomes were compared between UCS grades. A multinomial logistic regression was performed to estimate relative risk ratios (RRR) of variables on UCS grade

The shape of the flexion gap in 20 normal knees was evaluated by axial radiography of the distal femur, and the results compared with those obtained in a previous study by MRI. The observed asymmetry was reduced by 29% using radiography, with a mean value of 3.6° (1.5° to 6.3°) compared with that obtained by MRI of 5.1° (2.6° to 9.5°), a mean discrepancy of 1.49°. The results obtained by radiography and MRI showed a strong correlation (r = 0.78). Axial radiography is acceptable for the evaluation of the flexion gap and is less expensive and more comfortable to perform than MRI. Additionally, no metallic artefact occurs when the radiological method is used for assessment after arthroplasty

Background. Dislocation is a common complication following total hip arthroplasty (THA), and accounts for a high percentage of subsequent revisions. The purpose of this study was to develop a convolutional neural network (CNN) model to identify patients at high risk for dislocation based on postoperative anteroposterior (AP) pelvis radiographs. Methods. We retrospectively evaluated radiographs for a cohort of 13,970 primary THAs with 374 dislocations over 5 years of follow-up. Overall, 1,490 radiographs from dislocated and 91,094 from non-dislocated THAs were included in the analysis. A CNN object detection model (YOLO-V3) was trained to crop the images by centering on the femoral head. A ResNet18 classifier was trained to predict subsequent hip dislocation from the cropped imaging. The ResNet18 classifier was initialized with ImageNet weights and trained using FastAI (V1.0) running on PyTorch. The training was run for 15 epochs using ten-fold cross validation, data oversampling and augmentation. Results. The hip dislocation prediction classifier achieved the following mean performance: accuracy= 49.5(±4.1)%, sensitivity= 89.0(±2.2)%, specificity= 48.8(±4.2)%, positive predictive value= 3.3(±0.3)%, negative predictive value= 99.5(±0.1)%, and area under the receiver operating characteristic curve= 76.7(±3.6)%. Saliency maps demonstrated that the model placed the greatest emphasis on the femoral head and acetabular component. Conclusions. Existing prediction methods fail to identify patients at high risk of dislocation following THA. Our prediction model has high sensitivity and negative predictive value. Therefore, it can be helpful in rapid assessment of risk for dislocation following THA. The model further suggests radiographic locations which may be important in understanding the etiology of prosthesis dislocation

Diagnostic interpretation error of paediatric musculoskeletal (MSK) radiographs can lead to late presentation of injuries that subsequently require more invasive surgical interventions with increased risks of morbidity. We aimed to determine the radiograph factors that resulted in diagnostic interpretation challenges for emergency physicians reviewing pediatric MSK radiographs.

Emergency physicians provided diagnostic interpretations on 1,850 pediatric MSK radiographs via their participation in a web-based education platform. From this data, we derived interpretation difficulty scores for each radiograph using item response theory. We classified each radiograph by body region, diagnosis (fracture/dislocation absent or present), and, where applicable, the specific fracture location(s) and morphology(ies). We compared the interpretation difficulty scores by diagnosis, fracture location, and morphology. An expert panel reviewed the 65 most commonly misdiagnosed radiographs without a fracture/dislocation to identify normal imaging findings that were commonly mistaken for fractures.

We included data from 244 emergency physicians, which resulted in 185,653 unique radiograph interpretations, 42,689 (23.0%) of which were diagnostic errors. For humerus, elbow, forearm, wrist, femur, knee, tibia-fibula radiographs, those without a fracture had higher interpretation difficulty scores relative to those with a fracture; the opposite was true for the hand, pelvis, foot, and ankle radiographs (p < 0 .004 for all comparisons). The descriptive review demonstrated that specific normal anatomy, overlapping bones, and external artefact from muscle or skin folds were often mistaken for fractures. There was a significant difference in difficulty score by anatomic locations of the fracture in the elbow, pelvis, and ankle (p < 0 .004 for all comparisons). Ankle and elbow growth plate, fibular avulsion, and humerus condylar were more difficult to diagnose than other fracture patterns (p < 0 .004 for all comparisons).

We identified actionable learning opportunities in paediatric MSK radiograph interpretation for emergency physicians. We will use this information to design targeted education to referring emergency physicians and their trainees with an aim to decrease delayed and missed paediatric MSK injuries.

Diagnostic interpretation error of paediatric musculoskeletal (MSK) radiographs can lead to late presentation of injuries that subsequently require more invasive surgical interventions with increased risks of morbidity. We aimed to determine the radiograph factors that resulted in diagnostic interpretation challenges for emergency physicians reviewing pediatric MSK radiographs.

Emergency physicians provided diagnostic interpretations on 1,850 pediatric MSK radiographs via their participation in a web-based education platform. From this data, we derived interpretation difficulty scores for each radiograph using item response theory. We classified each radiograph by body region, diagnosis (fracture/dislocation absent or present), and, where applicable, the specific fracture location(s) and morphology(ies). We compared the interpretation difficulty scores by diagnosis, fracture location, and morphology. An expert panel reviewed the 65 most commonly misdiagnosed radiographs without a fracture/dislocation to identify normal imaging findings that were commonly mistaken for fractures.

We included data from 244 emergency physicians, which resulted in 185,653 unique radiograph interpretations, 42,689 (23.0%) of which were diagnostic errors. For humerus, elbow, forearm, wrist, femur, knee, tibia-fibula radiographs, those without a fracture had higher interpretation difficulty scores relative to those with a fracture; the opposite was true for the hand, pelvis, foot, and ankle radiographs (p < 0 .004 for all comparisons). The descriptive review demonstrated that specific normal anatomy, overlapping bones, and external artefact from muscle or skin folds were often mistaken for fractures. There was a significant difference in difficulty score by anatomic locations of the fracture in the elbow, pelvis, and ankle (p < 0 .004 for all comparisons). Ankle and elbow growth plate, fibular avulsion, and humerus condylar were more difficult to diagnose than other fracture patterns (p < 0 .004 for all comparisons).

We identified actionable learning opportunities in paediatric MSK radiograph interpretation for emergency physicians. We will use this information to design targeted education to referring emergency physicians and their trainees with an aim to decrease delayed and missed paediatric MSK injuries.

INTRODUCTION. Despite our best efforts, orthopaedic surgeons do not always achieve desired results in acetabular cup positioning in total hip arthroplasty. New advancements in digital radiography and image analysis software allow contemporaneous assessment of cup position in real-time during the surgical procedure. The purpose of this study was to describe and validate a technique in obtaining a true AP Pelvis radiograph in the lateral decubitus position to accurately assess cup position intra-operatively (Figure 1). METHODS. 350 consecutive patients undergoing THA through a soft-tissue sparing posterior approach were prospectively enrolled. Standard pre-operative supine radiographs were taken in the office to serve as a reference for intra-operative pelvic orientation and templating. Intra-operative AP Pelvis radiographs were obtained with the patient in the lateral decubitus position to appropriately match the pre-operative radiograph. Adjustments were made to correct for pelvic rotation by rotating the operating room table forward or backward. Radiographic beam angle adjustments allowed the surgeon to match pre-operative and intra-operative pelvic tilt (Figure 2). Two independent observers measured cup abduction angle. RESULTS. 95% of cups were placed within 30–50 degrees of abduction, with a mean angle of 38 degrees (STD +/− 5). 100% of cups measured post-operatively were placed within 3 degrees of their intra-operative measurement. Mean anteversion was 27.5 degrees (STD +/− 3.5). Intra-operative radiographs were repeated in 88% of cases in order to match to the pre-operative radiographs. The cup was repositioned in 28% of cases based on intra-operative measurements. Impingement during range of motion testing occurred in 3% of cases despite acceptable measurements, necessitating cup reposition. The intercross correlation coefficient between the two observers was 0.92. There was one dislocation reported in the 2-year follow-up. Changes in the pelvic inlet and outlet orientation changed the abduction angle measurement in a predictable way. We developed a formula and 3D model to predict the abudction angle based on the pelvic tilt, where a more outlet view would increase the abduction angle measurement (Figure 3). DISCUSSION AND CONCLUSION. Advancements in digital radiography allow for real-time cup position assessment, creating the opportunity for the surgeon to make the appropriate changes and confirm precise placement during the procedure. For figures/tables, please contact authors directly.

Aims. The aim of this study was to evaluate the survival of a collarless, straight, hydroxyapatite-coated femoral stem in total hip arthroplasty (THA) at a minimum follow-up of 20 years. Methods. We reviewed the results of 165 THAs using the Omnifit HA system in 138 patients, performed between August 1993 and December 1999. The mean age of the patients at the time of surgery was 46 years (20 to 77). Avascular necrosis was the most common indication for THA, followed by ankylosing spondylitis and primary osteoarthritis. The mean follow-up was 22 years (20 to 31). At 20 and 25 years, 113 THAs in 91 patients and 63 THAs in 55 patients were available for review, respectively, while others died or were lost to follow-up. Kaplan-Meier analysis was performed to evaluate the survival of the stem. Radiographs were reviewed regularly, and the stability of the stem was evaluated using the Engh classification. Results. A total of seven stems (4.2%) were revised during the study period: one for aseptic loosening, three for periprosthetic fracture, two for infection, and one for recurrent dislocation. At 20 years, survival with revision of the stem for any indication and for aseptic loosening as the endpoint was 96.0% (95% confidence interval (CI) 92.6 to 99.5) and 98.4% (95% CI 96.2 to 100), respectively. At 25 years, the corresponding rates of survival were 94.5% (95% CI 89.9 to 99.3) and 98.1% (95% CI 95.7 to 99.6), respectively. There was radiological evidence of stable bony fixation in 86 stems (76.1%) and evidence of loosening in four (3.5%) at 20 years. All patients with radiological evidence of loosening were asymptomatic. Conclusion. The Omnifit HA femoral stem offered promising long-term survival into the third decade. Cite this article: Bone Joint J 2024;106-B(3 Supple A):110–114

Pelvic x-ray is a routine part of the primary survey of Advanced Trauma Life Support (ATLS) guidelines. However, pelvic CT is the gold standard in the diagnosis of pelvic fractures. This study aims to confirm the safety of a modified ATLS algorithm omitting pelvic x-ray in hemodynamically stable polytraumatized patients with clinically stable pelvis, in favour of later pelvic CT scan.

A retrospective analysis of polytraumatized patients in our emergency room was conducted between 2005 and 2006. Inclusion criteria were blunt abdominal trauma, initial hemodynamic stability and clinically stable pelvis. We excluded patients requiring immediate intervention.

We reviewed the records of 452 patients. 91 fulfilled inclusion criteria (56% male, mean age 45 years). 43% were road traffic accidents and 47% falls. In 68/91 (75%) patients, both pelvic x-ray and CT examination were performed; the remainder had only pelvic CT. In 6/68 (9%) patients, pelvic fracture was diagnosed by pelvic x-ray. None false positive pelvic x-ray was detected. In 3/68 (4%) cases a fracture was missed in the pelvic x-ray, but confirmed on CT. 5 (56%) were classified type A fractures, and another 4 (44%) B 2.1 in computed tomography (AO classification). One A 2.1 fracture was found in a clinically stable patient who only received CT scan (1/23).

In hemodynamically stable patients with clinically stable pelvis, x-ray sensitivity is only 67% and it may safely be omitted in favor of a pelvic CT examination. The results support the safety and utility of our modified ATLS algorithm

Fluoroscopic C-arms are operated by medical radiography technologists (RTs) in Canadian operating rooms (ORs). While they do receive formal, accredited training, most of it is theoretical, rather than hands-on. During their first encounters in the OR, new RTs can experience difficulty achieving the radiographic views required by surgeons, often needing several scout X-rays during C-arm positioning. Furthermore, ambiguous language by surgeons often inadequately conveys their request. The result is often frustration, unnecessary radiation exposure, and added OR time. The purpose of this study was to evaluate the value of artificial X-rays in improving C-arm positioning performance, with inexperienced C-arm users. We developed an Artificial X-ray Imaging System (AXIS) that generates Digitally Reconstructed Radiographs (DRRs), or artificial X-ray images, based on the relative position of a C-arm and manikin. 30 participants were enrolled in the user study and performed four activities: an introduction session, an AXIS-guided evaluation, a non-AXIS-guided evaluation, and a questionnaire. The main goal of the study was to assess C-arm positioning performance with and without AXIS guidance. For each evaluation, the participants had to replicate a set of target X-ray images by taking real radiographs of the manikin with the C-arm. During the AXIS evaluation, artificial X-rays were generated at 2 Hz for guidance, while in the non-AXIS evaluation, the participants had to acquire real scout X-rays to guide them toward the correct view. For each imaging task the number of real X-rays and time required per task was recorded, and the C-arm's pose was tracked and compared to the target pose to determine positioning accuracy; these were averaged for each participant and condition. Hypothesis testing on the means and paired t-tests were carried out using a significance level of α=0.05. On average, users took significantly fewer real scout X-ray images (53% fewer (2.8 vs 6.0), p<0.001) when guided by AXIS. Lateral distance accuracy was improved by 10% for final C- arm positions and by 26% for the most accurate intermediate C-arm positions when guided by AXIS (p<0.05). There was no significant difference in average task time or angular accuracies between the AXIS and non-AXIS evaluations. Overall, we are encouraged by these findings and plan to further develop this system with the goal of deploying it both for training and intraoperative uses

Accurate measurement of pelvic tilt (PT) is critical in diagnosing hip and spine pathologies. Yet a sagittal pelvic radiograph with good quality is not always available. Studies explored the correlation between PT and sacro-femoral-pubic (SFP) angle from anteroposterior (AP) radiographs yet demonstrated conflicting conclusions about its feasibilities. This study aims to perform a cohort-controlled meta-analysis to examine the correlation between the SFP angle and PT and proposes an application range of the method.

This study searched PubMed, Embase, Cochrane, and Web of Science databases for studies that evaluated the correlation between SFP angle and PT. The Pearson's correlation coefficient r from studies were tabulated and compared. Pooled r for overall and gender/age (teenage or adult) controlled subgroup were reported using Fisher's Z transformation. Heterogeneity and publication bias were evaluated using Egger's regression test for the funnel plot asymmetry.

Eleven studies were recruited, with nine reported r (totalling 1,247 patients). The overall pooled r was 0.61 with high inter-study heterogeneity (I2 = 75.95%). Subgroup analysis showed that the adult group had a higher r than the teenage group (0.70 versus 0.56, p < 0.001). Although statistically insignificant (p = 0.062), the female group showed a higher r than the male group (0.72 versus 0.65).

The SFP method must be used with caution and should not be used in the male teenage group. The current studies did not demonstrate that the SFP method was superior to other AP landmarks correlating to PT. Identical heterogeneity was observed among studies, indicating that more ethnicity-segregated and gender-specific subgroup studies might be necessary. More data input analysing the errors will be useful.

Aims. There is little information in the literature about the use of dual-mobility (DM) bearings in preventing re-dislocation in revision total hip arthroplasty (THA). The aim of this study was to compare the use of DM bearings, standard bearings, and constrained liners in revision THA for recurrent dislocation, and to identify risk factors for re-dislocation. Methods. We reviewed 86 consecutive revision THAs performed for dislocation between August 2012 and July 2019. A total of 38 revisions (44.2%) involved a DM bearing, while 39 (45.3%) and nine (10.5%) involved a standard bearing and a constrained liner, respectively. Rates of re-dislocation, re-revision for dislocation, and overall re-revision were compared. Radiographs were assessed for the positioning of the acetabular component, the restoration of the centre of rotation, leg length, and offset. Risk factors for re-dislocation were determined by Cox regression analysis. The modified Harris Hip Scores (mHHSs) were recorded. The mean age of the patients at the time of revision was 70 years (43 to 88); 54 were female (62.8%). The mean follow-up was 5.0 years (2.0 to 8.75). Results. DM bearings were used significantly more frequently in elderly patients (p = 0.003) and in hips with abductor deficiency (p < 0.001). The re-dislocation rate was 13.2% for DM bearings compared with 17.9% for standard bearings, and 22.2% for constrained liners (p = 0.432). Re-revision-free survival for DM bearings was 84% (95% confidence interval (CI) 0.77 to 0.91) compared with 74% (95% CI 0.67 to 0.81) for standard articulations, and 67% (95% CI 0.51 to 0.82) for constrained liners (p = 0.361). Younger age (hazard ratio (HR) 0.92 (95% CI 0.85 to 0.99); p = 0.031), lower comorbidity (HR 0.44 (95% CI 0.20 to 0.95); p = 0.037), smaller heads (HR 0.80 (95% CI 0.64 to 0.99); p = 0.046), and retention of the acetabular component (HR 8.26 (95% CI 1.37 to 49.96); p = 0.022) were significantly associated with re-dislocation. All DM bearings which re-dislocated were in patients with abductor muscle deficiency (HR 48.34 (95% CI 0.03 to 7,737.98); p = 0.303). The radiological analysis did not reveal a significant relationship between restoration of the geometry of the hip and re-dislocation. The mean mHHSs significantly improved from 43 points (0 to 88) to 67 points (20 to 91; p < 0.001) at the final follow-up, with no differences between the types of bearing. Conclusion. We found that the use of DM bearings reduced the rates of re-dislocation and re-revision in revision THA for recurrent dislocation, but did not guarantee stability. Abductor deficiency is an important predictor of persistent instability. Cite this article: Bone Joint J 2024;106-B(5 Supple B):89–97

Acetabular component orientation can directly influence dislocation rates, polyethylene wear, and revision rates. Precise placement has been found to occur in only 38–47% after total hip arthroplasty (THA). The recent introduction of digital radiography (DR) has enabled a paradigm shift in intra-operative imaging technology. Rather than deal with the cumbersome process of chemical image processing we can now acquire a high quality digital image in a matter of seconds. The functionality approaches that of fluoroscopy, or even a C-arm, however, a digital system can operate with lower radiation, higher resolution, and perhaps most importantly a larger field of view. These features make it very suitable for use during surgery. The purpose of this presentation is to illustrate the current intra-operative technique and share the overwhelmingly positive experience gathered over the past five years. Traditional THA employs use of post-operative radiography for “outcome assessment.” This unfortunately does not allow the surgeon to evaluate the relevant parameters and make necessary adjustments without returning to the operating room. Digital imaging, however, permits intra-operative guidance and “outcome control.” It provides an immediate and complete preview of what the post-operative film will show. There is now an opportunity to optimise component orientation, sizing, apposition, screw position, limb length, and offset, before leaving the operating room. This can be done with minimal intrusion on normal workflow, adding only a few minutes of operating time

Introduction

Low dose technology of an EOS scanner allows mechanical axis radiographs to be produced using a continuously moving x-ray emitting a thin beam to form a single image which includes all three joints, without the need for stitching. The aim of this study was to identify necessary improvements to enable effective interpretation of the radiographs, and to assess whether the quality of the radiographs varied by production method compared to a previous audit of CR and DR radiographs.

A radiographic method is described for making the diagnosis of talo-navicular subluxation before ossification of the navicular bone occurs. Seven basic combinations of deformities are thought to occur in the club foot. Radiography before operation enables the surgeon to determine which of these combinations exists in a particular foot, and radiography during operation enables him to determine wheter or not all the existing deformities have been corrected, and therefore whether or not the operation must be extended

Identifying and restoring alignment is a primary aim of total knee arthroplasty (TKA). In the coronal plane, the pre-pathological hip knee angle can be predicted using an arithmetic method (aHKA) by measuring the medial proximal tibial angle (MPTA) and lateral distal femoral angle (aHKA=MPTA - LDFA). The aHKA is shown to be predictive of coronal alignment prior to the onset of osteoarthritis; a useful guide when considering a non-mechanically aligned TKA. The aim of this study is to investigate the intra- and inter-observer accuracy of aHKA measurements on long leg standing radiographs (LLR) and preoperative Mako CT planning scans (CTs).

Sixty-eight patients who underwent TKA from 2020–2021 with pre-operative LLR and CTs were included. Three observers (Surgeon, Fellow, Registrar) measured the LDFA and MPTA on LLR and CT independently on three separate occasions, to determine aHKA. Statistical analysis was undertaken with Bland-Altman test and coefficient of repeatability.

An average intra-observer measurement error of 3.5° on LLR and 1.73° on CTs for MPTA was detected. Inter-observer errors were 2.74° on LLR and 1.28° on CTs. For LDFA, average intra-observer measurement error was 2.93° on LLR and 2.3° on CTs, with inter-observer errors of 2.31° on LLR and 1.92° on CTs. Average aHKA intra-observer error was 4.8° on LLR and 2.82° on CTs. Inter-observer error of 3.56° for LLR and 2.0° on CTs was measured.

The aHKA is reproducible on both LLR and CT. CT measurements are more reproducible both between and within observers. The difference between measurements using LLR and CT is small and hence these two can be considered interchangeable. CT may obviate the need for LLRs and may overcome difficulties associated with positioning, rotation, body habitus and flexion contractures when assessing coronal alignment.

Abstract

Despite our best efforts, orthopaedic surgeons do not always achieve desired results in acetabular cup positioning in total hip arthroplasty (THA). Although ideal abduction and anteversion angles vary depending on surgeon preference, patient factors and anatomy, studies have shown that improperly positioned cups lead to increased failure rates in THA. While there have been many technological advancements in THA, including using CT-guided and fluoroscopic techniques, the cost for the hospital and time required to use this technology sometimes force hospitals not to use them. New advancements in digital radiography and image analysis software allow contemporaneous assessment of cup position in real-time during the surgical procedure. Intra-operative, or “trial radiographs” with the patient in lateral decubitus position can be digitally manipulated to match pre-operative radiographs obtained with patients in the supine position to enable calculation of the abduction and anteversion angle in these patients. In our single surgeon experience, digital radiography takes approximately 4–6 seconds in order to obtain an AP pelvic radiograph. The use of the software to measure the cup position adds only 1–2 minutes to the operative time and minimises interference with workflow. The adjustments that can be made intra-operatively with this technology allow the surgeon to learn what factors in his surgical approach and technique are useful in achieving the desired component position. This allows the surgeon to have precise control over the cup position during the operation rather than experience disappointment and frustration while viewing the post-operative film. This cost-effective and efficient tool allows the surgeons to achieve the best results for their patients in real time without having to leave the operating room

Introduction. In prosthetic knee surgery, the axis of the lower limb is often determined only by static radiographic analysis. However, it is relevant to determine if this axis varies during walking, as this may alter the stresses on the implants. The aim of this study was to determine whether pre-operative measurement of the mechanical femorotibial axis (mFTA) varies between static and dynamic analysis in isolated medial femorotibial osteoarthritis. Methods. Twenty patients scheduled for robotic-assisted medial unicompartmental knee arthroplasty (UKA) were included in this prospective study. We compared three measurements of the coronal femorotibial axis: in a static and weightbearing position (on long leg radiographs), in a dynamic but non-weightbearing position (intra-operative acquisition during robotic-assisted UKA), and in a dynamic and weightbearing position (during walking by a gait analysis). Results. There was no significant difference in the mFTA between radiological (173.9 ± 3.3°), robotic (174.4 ± 3.4°), and gait analysis (172.9 ± 5.1°) measurements (p < 0.05). Conclusion. There is no significant variation in varus between lying, standing, and while walking in patients who are candidates for medial UKA. This study also allows us to validate the accuracy of the robotic system in varus estimation, and to rely on intra-operative planning as it also reflects the dynamic knee under load

Bone ingrowth fixation of large diameter, beaded cobalt chromium cups is generally considered to be reliable but this is typically judged radiographically. To date, implant retrieval data of attached bone has been limited. This study evaluated correlations between the pre-revision radiographic appearance and the measured amount of bone attachment on one design of porous coated cup. Methods. Twenty-six monoblock, CoCr Birmingham Hip Resurfacing (BHR, Smith and Nephew, TN, USA) cups with macroscopic beads and hydroxyapatite coating were studied. Seventeen were revised for acetabular malposition with the remainder revised for femoral loosening (4), pain (1), infection (1), dislocation (1) or lysis (2). Median time to revision was 35 months (10 – 70 months). Ten patients were female; the median age of all patients was 54 years. The pre-revision radiographs were visually ranked for cup-bone integration as follows: 0 = none, 1 = < 50%, 2 = 50 – 75%, 3 = 76 – 95%, 4 = > 96% integration. Rankings were made for the superior and inferior aspects, without knowledge of the appearance of bone on the retrievals. The revised cups were photographed at an angle so the dome and the cup periphery were visualized. The area of bone in four equal segments in each of the superior and inferior aspects was measured with image analysis software. A probe was used to differentiate bone from soft tissue. Only bone that covered the beads was counted. Correlation coefficients were calculated for the radiographic and image analysis data. Results. Radiographically, most cups were assessed as having more than 50% of bone attachment and 7 cups were ranked as having almost total integration with bone. Only 2 cups were assessed radiographically as fully loose. Measured total bone attachment ranged from none to 55%. Superior and inferior percent ingrowth were highly correlated (corr=0.68, p<0.001) but there was no correlation between percent bone and x-ray rank (inferior corr=0.01, p=0.96; superior corr=0.23, p=0.26). There was no correlation between cup malpositioning as a reason for revision and x-ray integration ranking (superior p=0.34; inferior p=0.80). Discussion. Despite the radiographic appearance of good fixation, there was little or no correlation between percent area of actual bone attachment and x-ray appearance. One study limitation is the assumption that attached bone was indeed integrated with the beads as destructive sectioning was not done to verify this. Published autopsy retrieval studies have shown that even a small amount of actual ingrowth can provide clinically successful fixation. Another possible limitation was the variable quality of the radiographs. Never-the-less these results raise questions about the accuracy of radiographic analysis of bone fixation. The possibility that inadequate fixation is a cause for pain leading to revision should be considered even when the radiographic appearance indicates otherwise

We have previously developed a radiographic technique, the oblique posterior condylar view, for assessment of the posterior aspect of the femoral condyles after total knee arthroplasty. The purpose of this study was to confirm the validity of this radiographic view based upon intra-operative findings at revision total knee arthroplasty. Lateral and oblique posterior condylar views were performed for 11 knees prior to revision total knee arthroplasty, and radiolucent lines or osteolysis of the posterior aspect of the femoral condyles were identified. These findings were compared with the intra-operative appearance of the posterior aspects of the femoral condyles. Statistical analysis showed that sensitivity and efficacy were significantly better for the oblique posterior condylar than the lateral view. This method can, therefore, be considered as suitable for routine follow-up radiographs of the femoral component and in the pre-operative planning of revision surgery

The accurate assessment of compartmental involvement in degenerative arthritis of the knee is important when planning operative treatment. Standard radiographic techniques often fail to define the degree of involvement of the less affected tibiofemoral compartment. The use of stress radiography in the preoperative assessment of 30 knees with degenerative arthritis is described and the radiographic findings correlated with the changes found at arthrotomy

Introduction: It could be shown that an ample number of classical hip parameters for radiographic quantification of hip morphology on anteroposterior (AP) pelvic radiographs vary significantly with individual pelvic tilt and rotation. This could be proven not only for classical hip parameters (e.g. the lateral centre edge angle) but also for more recently described radiographic features such as acetabular retroversion. The resulting misdiagnosis and misinterpretation can potentially impair a correct therapy for the patient. We developed fast and easy-to-use computer software to perform three-dimensional (3D) analysis of the individual hip joint morphology using two-dimensional (2D) AP pelvic radiographs. Landmarks extracted from the radiograph were combined with a cone beam x-ray projection model and a strong lateral pelvic radiograph to reconstruct 3D hip joints. Twenty-five parameters including quantification of femoral head coverage can be calculated for a neutral orientation. The aim of the study was to evaluate the validity of this method for tilt and rotation correction of the acetabular rim and associated radiographic parameters. Methods: The validation comprised three steps:. External validation;. internal validation; and. intra-/interobserver analysis. A series of x-rays of 30 cadaver pelves mounted on a flexible holding device were available for step 1 and 2. External validation comprised the comparison of radiographical parameters of the cadaver hips when determined with our software in comparison with CT-based measurements or actual radiographs in a neutral pelvic orientation as gold standard. Internal validation evaluated the consistency of the parameters when each single pelvis was calculated back from different random orientations to the same neutral pelvic position. The intra-/interobserver analysis investigated the reliability and reproducibility of all parameters with the help of 100 randomized, blinded AP pelvic radiographs of a consecutive patient series. Results:. All but one parameter (acetabular index) showed a substantial to almost perfect correlation with the CT-measurements. Internal validity was substantial to almost perfect for all parameters. There was a substantial to almost perfect reliability and reproducibility of all parameters except the acetabular index. Conclusion: The software could be shown to be an accurate, reliable and reproducible method for correction of AP pelvic radiographs. This computer-assisted method allows standardized evaluation of all relevant radiographic parameters for detection of anatomic morphologic differences. It will be used to study the influence of pelvic malorientation on the radiographic appearance of each individual parameter. In addition, it allows evaluating the clinical significance of standardizing pelvic parameters

Axial radiographs were obtained under valgus and external rotation stress at 45° of knee flexion with and without contraction of the quadriceps muscle in order to assess the dynamics of patellar subluxation or dislocation. The radiography was performed on 82 knees in 61 patients with patellofemoral instability, and on 44 normal knees. The lateral patellofemoral angle and the congruence angle were measured and compared with the conventional Merchant views. Both parameters showed greater differences between symptomatic and normal knees on the stress radiographs obtained without quadriceps contraction. There was a major difference in the lateral patellofemoral angles between the groups, which clearly distinguished symptomatic knees from normal controls. Congruence angles on stress radiography had a significant correlation with the functional scores obtained after a period of conservative treatment and a positive correlation with the frequency of patellar subluxation. When the quadriceps contracted, two patterns of patellar shift were observed. While the patella reduced into the trochlear groove in all normal knees and about 70% of the symptomatic knees, contraction of the quadriceps caused further subluxation of the patella in the remaining symptomatic knees. All the knee joints which showed this displacement failed to respond to conservative treatment and eventually required surgical treatment. Thus, this technique of stress radiography is a simple, cost-effective and useful method of evaluating patellar instability and predicting the prognosis

Two critical steps in achieving optimal results and minimizing complications (dislocation, lengthening, and intra-operative fracture) are careful pre-operative planning and more recently, the option of intra-operative imaging in order to optimise accurate and reproducible total hip replacement. The important issues to ascertain are relative limb length, offset and center of rotation. It is important to start the case knowing the patient's perception of their limb length. Patient perception is equally important, if not more important, than the radiographic assessment. On the acetabular side, the teardrop should be identified and the amount of reaming necessary to place the inferior margin of the acetabular component adjacent to the tear drop should be noted. Superiorly the amount of exposed metal that is expected to be seen during surgery should be measured in millimeters. Once the key issues of limb length, offset, center of rotation, and acetabular component position relative to the native acetabulum have been confirmed along with the expected sizing of the acetabular and femoral components, it is critical that the operative plan is reproduced at the time of surgery and this can best be consistently performed with the use of intra-operative imaging. Advances in digital imaging now make efficient, cost-effective assessment of hip replacement possible. Embedded software allows accurate confirmation of the pre-operative plan intra-operatively when correction of potential errors is easily possible. Such technology is now mature after years of clinical use and studies have confirmed its success in avoiding outliers and achieving optimal results

An uncomplicated, quantitative method of determining density from X-rays would be of extreme value to clinicians. In this study we perform a thorough assessment of applying a step wedge to grey level calibration method to X-rays obtained using Computed Radiography (CR). An Aluminium step wedge of ten, 5mm-thick steps was X-rayed with a Fuji CR system together with a knee phantom (3M) at various energy and Fuji processing settings. Automatic detection of the steps by means of the Hough transform was used to assess optimum CR settings. Background variation due to the anode Heel effect was evaluated by acquiring an “empty field” X-ray at different energy settings and with copper filtering. The effects of beam hardening were considered with a custom-made phantom which was also used to assess correcting for soft tissue and bone thickness. X-rays taken at higher energy settings and with wider windowing imaged the widest number of steps (nine) and gave the best accuracy in modelling the step thickness to grey level relationship. Fitting a straight line to the log of the net grey levels gives an excellent model of the data (R2 = 0.99). X-rays of copper sheeting show that automatic histogram analysis is performed by the Fuji CR system, which can have unpredictable effects on aluminium thickness to grey level relationship. Background variation in the anode-cathode direction due to the Heel effect was corrected with a 1D exponential model (R2 = 0.99), allowing position-independent measurements to be obtained. Correcting for bone thickness, soft tissue and beam hardening further improves measurement quality. Use of step wedge calibration to provide quantitative information on plain X-rays without altering their clinical quality is possible using digital radiography. However, a thorough assessment of the entire X-ray process is necessary to achieve accurate and comparable information

The recent introduction of digital radiography has enabled a paradigm shift in intra-operative imaging technology. Rather than deal with the cumbersome process of chemical image processing we can now acquire a high quality digital image in a matter of seconds. The functionality approaches that of fluoroscopy, or even a C-arm, however, a digital system can operate with lower radiation, higher resolution, and perhaps most importantly a larger field of view. These features and the greater ability for post-acquisition, digital image enhancement make it very suitable for use during surgery. The purpose of this presentation is to illustrate the intra-operative technique and share the overwhelmingly positive experience gathered over the past few years. The current paradigm in total hip arthroplasty (THA) employs use of post-operative radiography for “outcome assessment.” This unfortunately does not allow the surgeon to evaluate the relevant parameters and make necessary adjustments without returning to the operating room. The new paradigm, however, permits intra-operative guidance and “outcome control.” We now have an opportunity to add a “trial radiograph” to our practice of performing a trial reduction. This provides an immediate and complete preview of what the post-operative film will show. There is now an opportunity, during the course of any hip arthroplasty, to optimise component orientation, sizing, apposition, screw position, limb length, and offset, before leaving the operating room. This can be done with minimal intrusion on normal workflow, adding only a few minutes of operating time

Radiological examination is a useful tool in assessing osteoarthritis (OA) in the knee. We have compared the extent of osteoarthritis in the knee graded on radiographs and by intraoperative observation to determine if there is significant difference with relevance to preop-erative planning. Radiographs for fifty-eight patients were graded for OA under blind conditions using the Ahlback classification system and direct measurement of the medial and lateral joint spaces. Intraoperative assessment of the corresponding joint surfaces was performed under blind conditions by a separate surgeon and graded using the Outerbridge classification system. OA was found to be more common in the medial compartment than the lateral, both on radiographs and intraoperatively. Spearman correlation coefficient for the medial compartment comparing joint space narrowing and intraoperative assessment was −0.545. For the lateral compartment the Spearman correlation coefficient was lower at –0.406. Positive predictive values for OA in the medial and lateral compartments on radiography were 90% and 66.67% respectively. Negative predictive values for OA in the medial and lateral compartments on radiography were 44.74% and 34.69% respectively. Conclusion: We have demonstrated that although radiographs have reasonable to good accuracy at showing OA in both compartments the absence of OA on radiographs does not correlate well with the absence of OA in the knee. This is of importance when planning operations, particularly unicompartmental knee replacement, as intraoperative findings of bilateral disease will change the operation required

Radiological measurements are an essential component of the assessment of outcome following knee arthroplasty. However, plain radiographic techniques can be associated with significant projectional errors because they are a two-dimensional (2D) representation of a three-dimensional (3D) structure. Angles that are considered within the target zone on one film may be outside that zone on other films. Moreover, these parameters can be subject to significant inter-observer differences when measured. The aim of our study therefore was to quantify the variability between observers evaluating plain radiographs following Unicompartmental knee arthroplasty. Twenty-three observers, made up of Orthopaedic Consultants and trainees, were asked to measure the coronal and sagittal alignment of the tibial and femoral components from the post-operative long-leg plain radiograph of a Unicompartmental knee arthroplasty. A post-operative CT scan using the low dose Imperial knee protocol was obtained as well and analysed with 3D reconstruction software to measure the true values of these parameters. The accuracy and spread of the pain radiographic measurements were then compared with the values obtained on the CT. On the femoral side, the mean angle in coronal alignment was 1.5° varus (Range 3.8, SD 1, min 0.1, max 3.9), whereas the mean angle in sagittal alignment was 8.6° of flexion (Range 7.5, SD 1.5, Min 3.7, Max 11.2). The true values measured with CT were 2.4° and 11.0° respectively. As for the tibial component, the mean coronal alignment angle was 89.7° (Range 11.6, SD 3.3, Min 83.8, Max 95.4), and the mean posterior slope was 2.4° (Range 8.7, SD 1.6, Min -2, Max 6.7). The CT values for these were 87.6° and 2.7° respectively. We conclude that the plain radiographic measurements had a large scatter evidenced by the wide ranges in the values obtained by the different observers. If only the means are compared, the plain radiographic values were comparable with the true values obtained with CT (that is; accuracy was good) with differences ranging from 0.3° to 2.4°. The lack of precision can be avoided with the use of CT, particularly with the advent of low-dose scanning protocols

Purpose: To determine the need for routine serial radiographs in the management of forearm fractures in children. Material and Methods: A binational study was conducted in 202 consecutive children with closed forearm fractures. In the 91 patients with stable fractures that did not require reduction, clinical and radiographic examination was performed one week after the start of treatment and again on cast removal 4–6 weeks later. In the remaining 111 patients who underwent closed reduction, an additional X-ray was taken two weeks after cast placement. Outcome was defined as the occurrence of redisplacement. Results: Redisplacement occurred during the first 2 weeks of cast management in 9 of the children who required reduction and in none of the children who did not. Conclusion: Radiographs should be performed one week after cast placement for greenstick or complete fractures that do not require reduction, and repeated at 2 weeks from start of treatment for fractures that require reduction. They need not be performed on cast removal, if clinical examination does not show signs of nonunion or malalignment. The adoption of these recommendations will lead to more cost-effective management and will spare children unnecessary radiographic exposure

Iterative finite element (FE) models are used to simulate bone remodelling that takes place due to the surgical insertion of an implant or to simulate fracture healing. In such simulations element material properties are calculated after each iteration of solving the model. New material properties are calculated based on the results derived by the model during the last iteration. Once the FE model has gone through a number of such iterations it is often necessary to assess the remodelling that has taken place. The method widely used to do this is to analyse element Young's modulus plots taken at particular sections through the model. Although this method gives relevant information which is often helpful when comparing different implants, the information is rather abstract and is difficult to compare with patient data which is commonly in the form of radiographs. The authors suggest a simple technique that can be used to generate synthetic radiograph images from FE models. These images allow relatively easy comparisons of FE derived information with patient radiographs. Another clear advantage of this technique is that clinicians (who are familiar with reading radiographs) are able to understand and interpret them readily. To demonstrate the technique a three dimensional (3D) model of the proximal tibia implanted with an Oxford Unicompartmental Knee replacement was created based on CT data obtained from a cadaveric tibia. The model's initial element material properties were calculated from the same CT data set using a relationship between radiographic density and Young's modulus. The model was subject to simplified loading conditions and solved over 365 iterations representing one year of in vivo remodelling. After each iteration the element material properties were recalculated based on previously published remodelling rules. Next, synthetic anteroposterior radiographs were generated by back calculating radiographic densities from material properties of the model after 365 iterations. A 3D rectangular grid of sampling points which encapsulated the model was defined. For each of the elements in the FE model radiographic densities were back calculated based on the same relationships used to calculate material properties from radiographic densities. The radiographic density of each element was assigned to all the sampling grid points within the element. The 3D array of radiographic densities was summed in the anteroposterior direction thereby creating a 2D array of radiographic densities. This 2D array was plotted giving an image analogous to anteroposterior patient radiographs. Similar to a patient radiograph denser material appeared lighter while less dense material appeared darker. The resulting synthetic radiographs were compared to patient radiographs and found to have similar patterns of dark and light regions. The synthetic radiographs were relatively easy to produce based on the FE model results, represented FE results in a manner easily comparable to patient radiographs, and represented FE results in a clinician friendly manner