Aims. The purpose of this study was to develop a convolutional neural network (CNN) for fracture detection, classification, and identification of greater tuberosity displacement ≥ 1 cm, neck-shaft angle (NSA) ≤ 100°, shaft translation, and articular fracture involvement, on plain radiographs. Methods. The CNN was trained and tested on radiographs sourced from 11 hospitals in Australia and externally validated on radiographs from the Netherlands. Each radiograph was paired with corresponding CT scans to serve as the reference standard based on dual independent evaluation by trained researchers and attending orthopaedic surgeons. Presence of a fracture, classification (non- to minimally displaced; two-part, multipart, and glenohumeral dislocation), and four characteristics were determined on 2D and 3D CT scans and subsequently allocated to each series of radiographs. Fracture characteristics included greater tuberosity displacement ≥ 1 cm, NSA ≤ 100°, shaft translation (0% to < 75%, 75% to 95%, > 95%), and the extent of articular involvement (0% to < 15%, 15% to 35%, or > 35%). Results. For detection and classification, the algorithm was trained on 1,709 radiographs (n = 803), tested on 567 radiographs (n = 244), and subsequently externally validated on 535 radiographs (n = 227). For characterization, healthy shoulders and glenohumeral dislocation were excluded. The overall accuracy for fracture detection was 94% (area under the receiver operating characteristic curve (AUC) = 0.98) and for classification 78% (AUC 0.68 to 0.93). Accuracy to detect greater tuberosity fracture displacement ≥ 1 cm was 35.0% (AUC 0.57). The CNN did not recognize NSAs ≤ 100° (AUC 0.42), nor fractures with ≥ 75% shaft translation (AUC 0.51 to 0.53), or with ≥ 15% articular involvement (AUC 0.48 to 0.49). For all objectives, the model’s performance on the external dataset showed similar accuracy levels. Conclusion. CNNs proficiently rule out proximal humerus fractures on plain radiographs. Despite rigorous training methodology based on CT imaging with multi-rater consensus to serve as the reference standard, artificial intelligence-driven classification is insufficient for clinical implementation. The CNN exhibited poor diagnostic ability to detect greater tuberosity displacement ≥ 1 cm and failed to identify NSAs ≤ 100°, shaft translations, or articular fractures. Cite this article: Bone Joint J 2024;106-B(11):1348–1360

The radiological evaluation of the anterolateral femoral head is an essential tool for the assessment of the cam type of femoroacetabular impingement. CT, MRI and frog lateral plain radiographs have all been suggested as imaging options for this type of lesion. The alpha angle is accepted as a reliable indicator of the cam type of impingement and may also be used as an assessment for the successful operative correction of the cam lesion. We studied the alpha angles of 32 consecutive patients with femoroacetabular impingement. The angle measured on frog lateral radiographs using templating tools was compared with that measured on CT scans in order to assess the reliability of the frog lateral view in analysing the alpha angle in cam impingement. A high interobserver reliability was noted for the assessment of the alpha angle on the frog lateral view with an intraclass correlation coefficient of 0.83. The mean alpha angle measured on the frog lateral view was 58.71° (32° to 83.3°) and that by CT was 65.11° (30° to 102°). A poor intraclass correlation coefficient (0.08) was noted between the measurements using the two systems. The frog lateral plain radiograph is not reliable for measuring the alpha angle. Various factors may be responsible for this such as the projection of the radiograph, the positioning of the patient and the quality of the image. CT may be necessary for accurate measurement of the alpha angle

Several radiological methods of measuring anteversion of the acetabular component after total hip replacement (THR) have been described. These studies used different definitions and reference planes to compare methods, allowing for misinterpretation of the results. We compared the reliability and accuracy of five current methods using plain radiographs (those of Lewinnek, Widmer, Liaw, Pradhan, and Woo and Morrey) with CT measurements, using the same definition and reference plane. We retrospectively studied the plain radiographs and CT scans in 84 hips of 84 patients who underwent primary THR. Intra- and inter-observer reliability were high for the measurement of inclination and anteversion with all methods on plain radiographs and CT scans. The measurements of inclination on plain radiographs were similar to the measurements using CT (p = 0.043). The mean difference between CT measurements was 0.6° (-5.9° to 6.8°). Measurements using Widmer’s method were the most similar to those using CT (p = 0.088), with a mean difference between CT measurements of -0.9° (-10.4° to 9.1°), whereas the other four methods differed significantly from those using CT (p < 0.001). This study has shown that Widmer’s method is the best for evaluating the anteversion of the acetabular component on plain radiographs. Cite this article: Bone Joint J 2014; 96-B:597–603

Plain radiographs of 67 acute spinal compression fractures in 49 patients were analysed by subjective and objective criteria, using CT scans as the diagnostic standard for the diagnosis of burst fracture. Discriminant analysis correctly predicted the type of fracture in 88% of cases. Burst fractures, however, were almost as frequently misdiagnosed as being wedge compression fractures using this technique, compared with the reading of 25 films from patients without previous information. A quarter of the injuries would have been misdiagnosed had reliance been placed solely on the plain radiographs. CT scans of all patients with acute spinal compression fractures should be considered to decrease this potentially serious diagnostic error

Introduction: The most widely accepted method for measuring bone mineral density (BMD) is Dual-energy X-ray Absorptionmetry (DXA). However, the need for relatively expensive equipment and trained personnel lower the accessibility of DXA as a routine screening tool. Plain pelvic X-ray radiography is a simple and inexpensive examination. In principal, the gray level of the bone in the X-ray radiograph is related to BMD. However, several factors render plain X-ray radiographs of the hip unsuitable for BMD measurements, mainly the variability in X-ray exposure levels and the soft tissue surrounding the bone. In this study, we aimed to develop new modifications of plain X-ray radiography of the proximal femur. Patients and methods: The study population consisted of 18 women with an average age of 77 years (range 57–96 years) who were hospitalized due to a low-energy fracture of the neck of the femur. Each patient’s contralateral hip was radiographed with an aluminium step-wedge positioned near the hip as a standard reference, using a computerized radiography system. A DXA examination of the same hip followed the plain radiograph. On each radiograph, regions of interest (ROI) were determined in concordance with the ROI of the DXA examination. The mean gray level was measured for each ROI. The neck-shaft angle and the femoral head diameter were also measured. Results: Comparing the gray levels of the plain radiograph with the BMD levels obtained by the DXA revealed a coefficient ratio of R=0.499. Correction of the gray levels using the step wedge as a standard reference revealed a ratio of R=0.576. If further correction was made with measurement of the soft tissue gray levels, a ratio of R=0.708 was obtained. Using the anatomical measurements (neck-shaft angle and femoral head diameter), a ratio of R=0.948 was obtained. Conclusion: This study shows that a plain digital radiograph of the pelvis can provide valuable information concerning the bone mineral content of the proximal femur, which is comparable to the results of the DXA examination. Ultimately, the research can lead to the development of a fast, available and relatively inexpensive technique to diagnose osteoporosis

Metal-on-metal total hip replacement has been targeted at younger patients with anticipated long-term survival, but the effect of the production of metal ions is a concern because of their possible toxicity to cells. We have reviewed the results of the use of the Ultima hybrid metal-on-metal total hip replacement, with a cemented polished tapered femoral component with a 28 mm diameter and a cobalt-chrome (CoCr) modular head, articulating with a 28 mm CoCr acetabular bearing surface secured in a titanium alloy uncemented shell. Between 1997 and 2004, 545 patients with 652 affected hips underwent replacement using this system. Up to 31 January 2008, 90 (13.8%) hips in 82 patients had been revised. Pain was the sole reason for revision in 44 hips (48.9%) of which 35 had normal plain radiographs. Peri-prosthetic fractures occurred in 17 hips (18.9%) with early dislocation in three (3.3%) and late dislocation in 16 (17.8%). Infection was found in nine hips (10.0%). At operation, a range of changes was noted including cavities containing cloudy fluid under pressure, necrotic soft tissues with avulsed tendons and denuded osteonecrotic upper femora. Corrosion was frequently observed on the retrieved cemented part of the femoral component. Typically, the peri-operative findings confirmed those found on pre-operative metal artefact reduction sequence MRI and histological examination showed severe necrosis. Metal artefact reduction sequence MRI proved to be useful when investigating these patients with pain in the absence of adverse plain radiological features

Radiographic evaluation of the anterolateral femoral head is an essential tool for the assessment of cam type of femoroacetabular impingement. Computerised tomography (CT), magnetic resonance imaging and frog lateral plain radiograph views have all been suggested as imaging options for this type of lesion. Alpha angle is accepted as a reliable indicator of cam type of impingement and this may also be used as an assessment tool for successful operative correction of the cam lesion. The aim of our study was to analyse the reliability of frog lateral view plain radiographs to analyse the alpha angle in cam femoroacetabular impingement. Thirty two patients who presented with femoroac-etabular impingement were studied. Interobserver reliability for assessment of alpha angles on frog lateral radiographic view was analysed using intraclass correlation coefficient. The alpha angles measured on frog lateral views using digital templating tools were compared to those measured on CT scans. A high interobserver reliability was noted for the assessment of alpha angles on frog lateral views with a correlation coefficient of 0.83. The average alpha angles measured on frog lateral views was 58.71 degrees (range 32 to 83.3). The average alpha angle measured on CT was 65.11 degrees (range 30 to 102). However, a poor correlation (Spearman r of 0.2) was noted between the measurements using the two systems. Frog lateral plain radiographs are not reliable predictors of alpha angle. Various factors may be responsible for this such as the projection of the radiographs, patient positioning and quality of images. CT imaging may be necessary for accurate prediction of alpha angle

The purpose of our study was to assess the reproducibility and reliability of traditional radiographic methods of diagnosing trochlear dysplasia compared with the gold standard of MRI. Plain radiographs and MRI scans of 36 knees in 28 patients with proven trochlear dysplasia were compared with 18 controls in a single surgeon's practice. The sulcus angle on MRI and axial radiographs was measured. The lateral radiograph was assessed for adequacy, the crossing sign and the trochlear bump sign. The mean axial (radiograph) and MRI sulcus angles in the dysplastic group were 145° and 158° respectively (p=0.0001) compared to 135° and 138° in the control group (p=0.09). The crossing sign was present in 34 out of 36 lateral radiographs in the dysplastic group and 8 out of 18 in the control group equating to a sensitivity of 94% and specificity of 56%. The quality of the lateral radiograph did not significantly alter the sensitivity or specificity of the crossing sign (p=0.01). The bump sign was present in 22 out of 36 lateral radiographs in the dysplastic group and 1 out of 18 in the control group equating to a sensitivity of 61% and specificity of 94%. Our study shows that an increased radiographic sulcus angle is reliable in diagnosing trochlear dysplasia but underestimates it. The bump sign is a reliable predictor of trochlear dysplasia. The crossing sign is sensitive but not specific in diagnosing dysplasia

Background. Lisfranc fracture dislocations are uncommon injuries, which frequently require surgical intervention. Currently, there is varying evidence on the diagnostic utility of plain radiographs (XR) and CT in identifying Lisfranc injuries and concomitant fractures. Our aim was to identify the utility of XR as compared to CT, with the nul hypothesis that there was no difference in fracture identification. Methods. A retrospective assessment of patients who had sustained a Lisfranc injury between 2013 and 2022 across two trauma centres within the United Kingdom who underwent surgery. Pre-operative XR and CT images were reviewed independently by 2 reviewers to identify the presence of associated fractures. Results. A total of 175 patients were included. Our assessment identified that XR images significantly under-diagnosed all metatarsal and midfoot fractures. The largest discrepancies between XR and CT in their rates of detection were in fractures of the cuboid (5.7% vs 28%, p<0.001), medial cuneiform (20% vs 51%, p=0.008), lateral cuneiform (4% vs 36%, p=0.113), second metatarsal (57% vs 82%, p<0.001), third metatarsal (37% vs 61%, p<0.001) and fourth metatarsal (26% vs 43%, p<0.001). As compared to CT, the sensitivity of XR was low. The lowest sensitivity for identification however was lateral foot injuries, specifically fractures of the lateral cuneiform (sensitivity 7.94%, specificity 97.3%), cuboid (sensitivity 18.37%, specificity 99.21%), fourth (sensitivity 46.7%, specificity 89.80%) and fifth metatarsal (sensitivity 45.00%, specificity 96.10%). Conclusion. From our analysis, we can determine that XR significantly under-diagnoses associated injuries in patient sustaining an unstable Lisfranc injury, with lateral foot injuries being the worst identified. We advised the use of CT imaging in all cases for appropriate surgical planning

Introduction Controversy exists regarding the value of lumbar plain x-ray imaging for patients with low back pain with or without radicular pain (. 1. ,. 2. ,. 3. ). Methods Plain film x-ray and CT imaging from thirty (30; 19M:11F) consecutive patients (aged 20–68 years; mean 42 years) presenting to a public hospital’s spinal pain clinic with low back pain +/− radicular pain, without a history suggesting ‘red flag’ pathology, was examined and measured to determine the incidence of retrolisthesis of L5 on S1 and any associated disc bulge/protrusion. Results Sixteen of the thirty patients (53%) had retrolisthesis of L5 on S1 ranging from 2–9 mm; these patients had either intervertebral disc bulging or protrusion on CT examination ranging from 3–7 mm into the spinal canal. Fourteen patients (47%) without retrolisthesis (control group) did not show any retrolisthesis and the CT did not show any bulge/protrusion. On categorizing x-ray and CT pathology as being present or not, the well positioned ie. true lateral plain x-ray film revealed a sensitivity and specificity of 100% ([95% Conf. Int. = [89%–100%]) for bulge/protrusion in this preliminary study. On taking into account the numerical values of x-ray and CT, a significant correlation (p< 0.001) was found. Discussion In this preliminary study, carefully positioned lateral lumbosacral x-ray films showing L5 on S1 retrolisthesis are highly suggestive of intervertebral disc bulge/protrusion, providing valuable guidance for consideration of lumbosacral CT of MRI examination that is likely to be contributory regarding such pathology

Introduction: Several factors render plain X-ray radiographs of the hip unsuitable for bone mineral density measurements, mainly variability in X-ray exposure levels and soft tissue surrounding the bone. We present modification of proximal femur digital radiographs to compensate for these interfering factors. Methods: The study population consisted of 99 women, in three groups: 1 – elderly, sustaining a fracture of the neck of the femur. 2 – elderly, without a fracture. 3 – young. Each patient’s hip was radiographed with a brass step-wedge for standard reference. Dual-Energy X-ray Absorptiometry (DEXA) of the same hip was performed. On each radiograph, Regions Of Interest (ROIs) of the proximal femur were determined in concordance with ROI of the DEXA, together with three soft tissue regions surrounding the bone. Mean gray level was measured for each ROI. Results: The difference in gray level of the ROI within the proximal femur was not statistically significant between the groups. Correction of bone gray level to exposure level by dividing the gray level of the ROI to that of the step wedge, resulted in statistically significant difference between group 1 and either group 2 or group 3. Similar results were obtained by correction of bone gray level to soft tissue gray level. Using this method, multiple R. 2. of 0.62 was found predicting the DEXA value from the gray level of each ROI. Conclusions: After correction to the exposure level and to the soft tissue surrounding the bone, a plain digital radiograph of the pelvis can provide valuable information concerning the bone mineral content of the proximal femur. These preliminary results warrant further research aimed at exploring the potential value of this fast, accessible and relatively inexpensive technique to diagnose osteoporosis and the prediction of future fractures

Introduction: With increasing availability of CT scans their use in the investigation of the subtalar joint increases, whilst we continue to use plain x-ray. Using a standardised reporting protocol, we graded x-rays and CT scans to compare the diagnosis made using each modality. Materials and Methods: An atlas and reporting system of the subtalar joint was designed using a modification of Kellgren and Lawrence’s system. 50 consecutive CT scans of the subtalar joint were identified and saved along with paired plain x-rays of the foot and ankle. All investigations were anonymised. Scans were excluded if there were no plain films or there was evidence of previous trauma. Orthopaedic surgeons were asked to report on the 50 CT scans and 50 plain radiographs using the reporting protocol, commenting on two components for each investigation; the anterior and middle facets and the posterior facet of the subtalar joint. Results: In 33% of cases the facets of the subtalar joint could not be appreciated from the plain x-rays. The difference between the modalities in reported grade of degeneration of the anterior and middle facets of the subtalar joint was statistically significant (p= 0.014) but not for the posterior facet (0.726). When looking at the Spearman correlation coefficient, the anterior and middle facets had no correlation (r = − 0.067) although the posterior facet did (r = 0.029). Discussion: When looking at the posterior facet of the subtalar joint plain x-rays and CT scans give comparable results. When looking at the anterior and middle facets the information gained from the plain x-rays bears no resemblance to that gained from the CT scans. Conclusion: The plain x-ray is an inaccurate, unreliable method of investigating degenerate pathology of the subtalar joint and should be superseded, and perhaps replaced, by the CT scan

Objective: The purpose of the present study was to assess whether clinicians are actually able to evaluate the mechanical status of lengthening callus from plain radiographs. Materials and Methods: 36 rats were employed in this study. Their left femurs were lengthened by 6 mm as a bone lengthening model. Rats were euthanized at 4 8 12 and 16 weeks after lengthening. Both femora were X-rayed and then bone density parameters (bone mineral content, bone mineral density and bone area) of lengthening callus were measured using pQCT. Three-point bending test was performed to determine the mechanical strength of the both bones. We defined the ratio of the strength of lengthening side to control side as estimated strength recovery rate (%). Then 20 orthopaedic surgeons evaluated only the X-ray photographs and tried to estimate the relative mechanical strength (%) of the affected side compared to the control side. Results: Between the recovery percentage of mechanical strength and bone mineral content, a positive simple correlation (R2=0.11, p< 0.05) was seen. No significant correlation was seen between the recovery percentage of mechanical strength estimated by orthopaedists and the mechanical strength measured by three-point bending test (qualified doctors: R2=0.0793 p=0.291 unqualified doctors: R2=0.0523 p=0.394). Discussion and conclusion: It became obvious that to estimate the strength of lengthening callus from plain radiographs alone is quite difficult as compared with the studies of the simple fracture model that have been reported until now

Plain radiography has traditionally been used to investigate and monitor patients with adolescent idiopathic scoliosis. The X-ray allows a calculation of the Cobb angle which measures the degree of lateral curvature in the coronal plane. ISIS2 is a surface topography system which has evolved from ISIS, but with much higher precision and speed. It measures the three dimensional shape of the back using structured light and digital photography. This system has the benefit of not requiring any radiation. Lateral asymmetry is the ISIS clinical parameter estimating the curve of the spine in the coronal plane. The aim of this study was to compare this parameter to the Cobb angle measured on plain X-ray. Twelve patients with idiopathic adolescent scoliosis underwent both a standing AP spine X-ray and an ISIS2 scan on multiple occasions. Both scan and X-ray were done within one month of each other. No patient underwent surgery during the study period. The Cobb angle and the degree of lateral asymmetry were calculated. Twelve patients mean age 12.5 years (range 10-16) were investigated using both ISIS2 and X-ray. They had a mean 2.3 (1-5) combined investigations allowing for 30 comparisons. The correlation between the two measurements was r =0.63 (p=0.0002). The Cobb angle measured on ISIS2 was less than that measured by radiograph in 27 out of 30 comparisons. The mean difference between the measurements was mean 6.4° with a standard deviation of 8.2° and 95% confidence interval of 3.3° to 9.4°. In adolescent idiopathic scoliosis, curve severity and rib hump severity are related but measure different aspects of spinal deformity. As expected, these relate closely but not precisely. ISIS2 offers the promise of monitoring scoliosis precisely, without adverse effects from radiation. The small numbers in this series focus on the group of patients with mild to moderate curves at risk of progression. In this group, ISIS2 was able to identify curve stability or progression, without exposing the subjects to radiation

Aims

To explore the clinical relevance of joint space width (JSW) narrowing on standardized-flexion (SF) radiographs in the assessment of cartilage degeneration in specific subregions seen on MRI sequences in knee osteoarthritis (OA) with neutral, valgus, and varus alignments, and potential planning of partial knee arthroplasty.

To evaluate and describe the plain radiographic changes observed with time in fusions using SiS-CaP. We describe, for the first time, 4 stages of bone substitute fusion mass (BSFM) radiographic appearance in relation to time post-op. Retrospective, radiological evaluation. Over 200 plain radiographs were evaluated. 70 consecutive fusions for degenerative spinal stenosis were included, in all cases performed by the same surgeon using the same operative technique. Follow-up was from 3 months to 2 years post-op. Radiographs were evaluated for the presence or absence of SiS-CaP granules, bone formation and for evidence of pseudarthrosis. Trends were seen within the BSFM with respect to time. At 6-12 weeks post-op a ‘homogenous granular stage’ indicates the presence of the unchanged SiS-CaP. At 12 weeks, small pockets appear within the BSFM in the ‘vacuolation stage’, indicating bioresorption of the graft. Vacuoles become increasingly radio-opaque indicating bone proliferation during the ‘homogenous lamellar stage’. At variable time between 6 months and 2 years, the BSFM becomes encapsulated in the ‘cortication stage’ visible as a sclerotic rim around the BSFM. We have seen a clear trend in the behaviour of the fusion mass in this case series. The radiological stages we have described above can be closely correlated with previously reported in-vitro and in-vivo studies looking at the micro-function of SiS-CaP. We hope that this description will help to judge the progress of graft incorporation and fusion. Further study of inter and intra-observer correlation will be required

Introduction

There are conflicting views when assessing the best imaging modality by which to assess long leg alignment pre and post operatively for patients’ receiving primary total hip replacements. It has been a long standing standard that long-leg radiographs are used for measuring and interpreting alignment of the lower limb, but recently it has been suggested that CT imaging may be a better option for this assessment.

In total hip replacement, orientation of the cup is critical to the stability of the prosthesis. A new method to determine the angle of planar anteversion is described. A simple mathematical formula uses the measurements taken from anteroposterior radiographs to calculate the planar anteversion without reference to tables or charts.

An experimental study in vitro has shown the efficacy of the formula in giving results which are within a clinically acceptable range.

The purpose of this study was to devise a simple but reliable radiological method of identifying a lumbosacral transitional vertebra (LSTV) with a solid bony bridge on sagittal MRI, which could then be applied to a lateral radiograph.

The vertical mid-vertebral angle (VMVA) and the vertical anterior vertebral angle (VAVA) of the three most caudal segments of the lumbar spine were measured on MRI and/or on a lateral radiograph in 92 patients with a LSTV and 94 controls, and the differences per segment (Diff-VMVA and Diff-VAVA) were calculated. The Diff-VMVA of the two most caudal vertebrae was significantly higher in the control group (25° (sd 8) than in patients with a LSTV (type 2a+b: 16° (sd 9), type 3a+b: -9° (sd 10), type 4: -5° (sd 7); p < 0.001). A Diff-VMVA of ≤ +10° identified a LSTV with a solid bony bridge (type 3+4) with a sensitivity of 100% and a specificity of 89% on MRI and a sensitivity of 94% and a specificity of 74% on a lateral radiograph. A sensitivity of 100% could be achieved with a cut-off value of 28° for the Diff-VAVA, but with a lower specificity (76%) on MRI than with Diff-VMVA.

Using this simple method (Diff-VMVA ≤ +10°), solid bony bridging of the posterior elements of a LSTV, and therefore the first adjacent mobile segment, can be easily identified without the need for additional imaging.

Cite this article: Bone Joint J 2013;95-B:1533–7.